Cement and concrete compositions with 3D graphene carbons

Abstract

Cement compositions including ordinary Portland cement, a supplementary cementitious material (SCM) including one or more of, metakaolin, limestone, or gypsum in an amount of up to approximately 70% of a replacement level of ordinary Portland cement, and between approximately 0.05% by weight of cement (bwoc) and 2% bwoc of a carbon-based material including three-dimensional graphene flakes (3DG) carbons. Concrete compositions including the cement compositions with 3DG carbons. The 3DG carbons include aggregates of mesoporous carbon nanoparticles, which include one or more interconnected bundles of electrically conductive graphene layers. The 3DG carbons include oxygen containing functional groups or nano-silica particles disposed on one or more of the surfaces of the 3DG carbons or within the 3DG carbons.

Description

CEMENT AND CONCRETE COMPOSITIONS WITH 3D GRAPHENE CARBONS RELATED APPLICATIONS

[0001] This Patent Application claims priority to U.S. Provisional Patent Application No. 63 / 691,971 entitled “CEMENT AND CONCRETE COMPOSITIONS WITH 3D GRAPHENE CARBONS” filed on September 06, 2024, to U.S. Provisional Patent Application No. 63 / 634,852 entitled “CEMENT AND CONCRETE COMPOSITIONS WITH 3D GRAPHENE CARBONS” filed on April 16, 2024, to U.S. Patent Application No. 18 / 243,515 entitled “CEMENT COMPOSITIONS WITH 3D GRAPHENE CARBONS” filed on September 7, 2023, which is a continuation-in-part application claiming priority to International Patent Application No. PCT / US23 / 63476 entitled “CEMENT COMPOSITIONS WITH 3D GRAPHENE CARBONS” and filed on March 01, 2023, which claims priority to U.S. Provisional Patent Application No. 63 / 447,984 entitled “CEMENT COMPOSITIONS WITH 3D GRAPHENE CARBONS” filed on February 24, 2023, to U.S. Provisional Patent Application No. 63 / 316,597 entitled “USING 3D GRAPHENES TO REGULATE NUCLEATION AND TIME-LAPSED GROWTH DURING GELATION / FORMATION OF POLYMERIZED CHAINS IN CEMENTS” filed on March 4, 2022, all of which are assigned to the assignee hereof. The disclosures of all prior Applications are considered part of and are incorporated by reference in this Patent Application in their respective entireties. TECHNICAL FIELD

[0002] This disclosure relates generally to cement compositions, and, more particularly, to cement compositions that include a carbon-based material including three-dimensional graphene flakes. DESCRIPTION OF RELATED ART

[0003] Recent developments in cement compositions are focused on decreasing CO2 emissions of processes used for making and using cement. However, further improvements in cement compositions are desired.SUMMARY

[0004] This Summary is provided to introduce in a simplified form a selection of concepts that are further described below in the Detailed Description. This Summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to limit the scope of the claimed subject matter.

[0005] In some implementations, an example cement composition may include ordinary Portland cement, a supplementary cementitious material (“SCM”) including one or more of metakaolin, limestone, or gypsum in an amount between approximately 45% and approximately 70% replacement level of ordinary Portland cement, a superplasticizer in a concentration range of between approximately 0.05% by weight of cement (bwoc) and approximately 2% bwoc, and carbon-based material including three-dimensional graphene flakes (referred to as 3DG carbons in this disclosure) in amounts of between approximately 0.05% bwoc and approximately 2% bwoc. Each graphene flake may include few layers of graphene or multiple layers of graphene and may be characterized by a wavy or wrinkled morphology. The carbon-based material may include agglomerates of mesoporous carbon nanoparticles. The 3DG carbons may include a matrix of other allotropes of carbon including graphite with three-dimensional graphene flakes dispersed therein. In some aspects, the 3DG carbons may include oxygen containing functional groups disposed on one or more of the surfaces of the 3DG carbons or within the 3DG carbons. In some other aspects, an early age compressive strength measured using ASTM C109 at a hydration period of 3 days of the example cement composition may be greater than the corresponding minimum compressive strength requirement for hydraulic cements as specified under ASTM C1157. In some instances, the 3DG carbons including oxygen containing functional groups may be dispersed in water and added to the cement composition during hydration.

[0006] In some implementations, the mesoporous carbon nanoparticles in the example cement compositions may include one or more interconnected bundles of electrically conductive graphene layers. In some other implementations, the graphene layers may be arranged as one or more stacks. In some aspects, the one or more stacks may be connected to each other to define a 3D porous scaffold structure including mesopores. In some other aspects, the one or more stacks may be connected such that they are disposed substantially orthogonal to each other. In some aspects, the graphene layers may be characterized by a linear dimension of between about 50 nm to about 200 nm. In some other aspects, thegraphene layers may include one or more of single layer graphene (SLG), few layer graphene (FLG), or many layer graphene (MLG).

[0007] In some implementations, the 3DG carbons in the example cement compositions may be characterized by a Raman spectroscopy signature having an ID / IG ratio between approximately 0.95 and approximately 1.05. In some other implementations, the 3DG carbons may be characterized by a Brunauer–Emmett–Teller (BET) surface area measured using nitrogen gas of about 50 to 300 m2 / g.

[0008] In some implementations, the 3DG carbons in the example cement compositions may be characterized by a graphene to amorphous carbon ratio of between about 1% and 95%. In some other implementations, the 3DG carbons may be characterized by an electrical conductivity of between about 500 S / m and about 20,000 S / m when compressed at pressure of about 12,000 pounds per square inch (psi).

[0009] In some implementations, the oxygen containing functional groups may include one or more of epoxide (C–O–C), hydroxyl (–OH), ether (C–O–C), ketone (O–C=O), or carboxylic acid (–COOH) groups. In some aspects, the oxygen concentration associated with the oxygen containing functional groups may be between about 1 wt% and about 25 wt%. In some other aspects, the oxygen concentration associated with the oxygen containing functional groups disposed on the surface of the 3DG carbons may be between about 4 at% and about 5 at%.

[0010] In some implementations, the SCM in the example cement compositions may include (on a bwoc basis) between about 20 wt% and about 35 wt% metakaolin, between about 15% and about 40 wt% limestone, and between about 0.5 wt% and about 3.5 wt% gypsum.

[0011] In some implementations, the superplasticizer in the example cement compositions may include one or more of polycarboxylate ether, sulfonated naphthalene formaldehyde condensate, sulfonated melamine formaldehyde condensate, or acetone formaldehyde condensate.

[0012] In some implementations, an example method of making a mortar including any one of the cement compositions previously described may include mixing a cement blend with water at a water to cement ratio by weight of between approximately 0.3 and approximately 0.5 to form a first mixture. An example cement blend may include ordinary Portland cement, a supplementary cementitious material (“SCM”) including one or more of metakaolin, limestone, or gypsum in an amount between approximately 45% andapproximately 70% replacement level of ordinary Portland cement, and a superplasticizer in a concentration range of between approximately 0.05% bwoc and approximately 2% bwoc. In some implementations, the SCM may include between about 20 wt% and about 35 wt% metakaolin, between about 15% and about 40 wt% limestone, and between about 0.5 wt% and about 3.5 wt% gypsum, on a bwoc basis.

[0013] In some implementations, the example method may continue with mixing a suspension of 3DG carbons in water into the first mixture. The 3DG carbons may include any one or more of the carbon materials disclosed herein. For example, in some instances, the 3DG carbons may include one or more of oxygen containing functional groups or nano-silica particles disposed on one or more of the surfaces of the 3DG carbons or within the 3DG carbons. In some aspects, the amount of 3DG carbons in the example mortar may be between approximately 0.05% bwoc and approximately 2% bwoc.

[0014] In some implementations, the water absorption rate of the mortar measured using ASTM C1585 may be less than 1 mm at a square root time greater than 80 s1 / 2. The charge passed through value of the mortar measured using ASTM C1202 may be less than 200 coulombs after a curing period of 28 days. The non-steady state chloride migration coefficient of the mortar based on NT Build 492 tests may be less than 5 x 1012m2 / s after a curing period of 28 days.

[0015] In some implementations, an example cement composition may include ordinary Portland cement, a supplementary cementitious material (SCM) including one or more of metakaolin, limestone, or gypsum in an amount between approximately 45% and approximately 70% of a replacement level of ordinary Portland cement, a superplasticizer in a concentration range of between approximately 0.05% by weight of cement (bwoc) and 2% bwoc, and 3DG carbons in amounts of between approximately 0.05% bwoc and 2% bwoc. In some instances, the 3DG carbons may include nano-silica particles disposed on one or more of the surfaces of the 3DG carbons or within the 3DG carbons. In some other instance, an early age compressive strength of the example cement composition measured using ASTM C109 at a hydration period of 3 days may be greater than the corresponding minimum compressive strength requirement for hydraulic cements specified under ASTM C1157.

[0016] In some implementations, the 3DG carbons including nano-silica particles may be dispersed in water and added to the cement composition during hydration. In some instances, an example cement composition may further include oxygen containing functional groups disposed on one or more of the surfaces of the 3DG carbons or within the 3DG carbons.

[0017] In some implementations, an example a concrete composition may include between approximately 9 wt% and approximately 15 wt% ordinary Portland cement, between approximately 45 wt% and approximately 50 wt% coarse aggregates, between approximately 30 wt% and approximately 35 wt% fine aggregates, between approximately 5 wt% and approximately 10 wt% water and 3DG carbons in amounts of between approximately 0.05% bwoc and 0.5% bwoc. In some instances, the 3DG carbons may include one or more of nano- silica particles or oxygen containing functional groups disposed on one or more of the surfaces of the 3DG carbons or within the 3DG carbons. In some other instances, an example concrete composition may further include a superplasticizer in a concentration range of between approximately 0.05% bwoc and 2% bwoc.

[0018] In some implementations, an early age compressive strength of the example concrete composition measured using ASTM C39 at a hydration period of 7 days may be between about 4500 psi and 5000 psi. In some instances, an early age compressive strength of the example concrete composition measured using ASTM C39 at a hydration period of 7 days may be approximately 35% greater than the compressive strength of a corresponding concrete composition not including the 3DG carbons.

[0019] In some implementations, the average diameter of the coarse aggregates in the example concrete composition may be between approximately 0.375 in. and approximately 1.5 in. In some instances, the average diameter of the fine aggregates in the example concrete composition may be less than approximately 0.37 in.

[0020] In some implementations, an example cement composition may include ordinary Portland cement, a supplementary cementitious material (“SCM”) including pozzolan, in an amount corresponding to up to approximately 70% replacement level of ordinary Portland cement, and 3DG carbons. The amount of 3DG carbons may be between about 0.05% bwoc and 2% bwoc. The pozzolan may include between approximately 50 wt% and approximately 70 wt% SiO2, between approximately 10 wt% and 20 wt% Al2O3, and less than approximately 10 wt% each of Fe2O3and MgO. The loss on ignition (LOI) of the pozzolan may be less than approximately 10 wt%. The 3DG carbons may be characterized by a Raman spectroscopy signature having an ID / IG ratio between approximately 0.95 and approximately 1.05.

[0021] In some implementations, an example cement composition may include ordinary Portland cement, a SCM including one or more of metakaolin, slag, fly ash, pyroclastic ash, or limestone, in an amount corresponding to up to approximately 70% replacement level ofordinary Portland cement, and 3DG carbons. The amount of 3DG carbons may be between approximately 0.05% bwoc and approximately 2% bwoc. The amount of 3DG carbons may be between approximately 0.05% bwoc and approximately 1 % bwoc. The 3DG carbons may be surface functionalized with one or more of silicate compounds or nano-silica. The SCM may include between approximately 50 wt% and approximately 70 wt% SiO2, between approximately 10 wt% and approximately 20 wt% Al2O3, and less than approximately 10 wt% each of Fe2O3and MgO. The loss on ignition (LOI) of the SCM may be less than approximately 10 wt%. The 3DG carbons may be characterized by a Raman spectroscopy signature having an ID / IG ratio between approximately 0.95 and approximately 1.05. The 3DG carbons may be surface functionalized with one or more of silicon, sulfur, oxygen, nitrogen, silicon, lithium, sodium or potassium. The 3DG carbons surface functionalized with nano-silica may include between approximately 20 at. wt% and approximately 65 at. wt% Si, and between approximately 15 at. wt% and approximately 40 at. wt% O. The O / Si ratio of the 3DG carbons surface functionalized with nano-silica may be between approximately 1.5 and approximately 3.

[0022] In some implementations, an example cement composition may include ordinary Portland cement, a SCM including one or more of metakaolin, limestone, or gypsum, in an amount corresponding to up to approximately 70% replacement level of ordinary Portland cement, a superplasticizer in a concentration range of between approximately 0.05% by weight of cement (“bwoc”) and approximately 2% bwoc, and 3DG carbons. The amount of 3DG carbons may be between about 0.05% bwoc and 2% bwoc. The amount of 3DG carbons may be between about 0.05% bwoc and 1 % bwoc. The amount of gypsum may be between about 0.5 wt% and approximately 3.5 wt%. The superplasticizer may include a polycarboxylate ether, for example, Arkema’s Ethacryl product or BASF’s Liquiment product. The superplasticizer may be added to the cement paste during hydration as a dispersant. The example cement composition may further include rheology modifiers, that include, but are not limited to, hydroxyethylcellulose in a concentration range of between approximately 0.05% bwoc and approximately 1.0% bwoc. The 3DG carbons may be surface functionalized with one or more of silicate compounds or nano-silica. The SCM may include approximately 65 wt% metakaolin (or generally pozzolan), approximately 32 wt% limestone, and approximately 3 wt% gypsum. The SCM may include approximately 97 wt% of one or more of metakaolin or limestone, and approximately 3 wt% gypsum.

[0023] In some implementations, an example cement composition may include ordinary Portland cement, a supplementary cementitious material (SCM) including one or more of pyroclastic ash, slag, fly ash, metakaolin, or limestone in an amount corresponding to at least approximately 70% replacement level of ordinary Portland cement, and 3DG carbons. The amount of 3DG carbons may be between approximately 0.05% bwoc and approximately 2% bwoc. The amount of 3DG carbons may be between approximately 0.05% bwoc and approximately 1% bwoc. The 3DG carbons may include aggregates of carbon nanoparticles including graphene. The carbon nanoparticles may be characterized by a plurality of porous concentric shells including graphene, where each shell may enclose a porous carbon region. An interconnected porous network may be disposed in each carbon region and in fluid communication with contiguous carbon regions. The SCM may include between approximately 50 wt% and approximately 70 wt% SiO2, between approximately 10 wt% and 20 wt% Al2O3, and less than approximately 10 wt% each of Fe2O3 and MgO. The loss on ignition (LOI) of the pozzolan may be less than approximately 10 wt%. The 3DG carbons may be characterized by a Raman spectroscopy signature having an ID / IG ratio between about 0.95 and about 1.05. The size of the carbon nanoparticles may be between about 20 nm and about 750 nm. The size of the aggregates of carbon nanoparticles may be between about 50 nm and about 1500 nm. The size of the aggregates of carbon nanoparticles may be greater than about 2 µm. The 3DG carbons may surface etched using CO2 etching. The 3DG carbons may be surface oxidized or functionalized with ozone. The 3DG carbons may be surface functionalized with one or more of silicate compounds or nano-silica. The 3DG carbons surface functionalized with one or more of silicate compounds or nano-silica may include between approximately 20 at. wt% and approximately 65 at. wt% Si, and between approximately 15 at. wt% and approximately 40 at. wt% O. The O / Si ratio in the surface functionalized 3DG carbons may be between approximately 1.5 and approximately 3. The 3DG carbons may be surface functionalized with one or more of oxygen, nitrogen, silicon, sodium or potassium.

[0024] In some implementations, an example method for regulating calcium-silicate- hydrate (“CSH”) nucleation and time-lapsed growth during the initial hydration of cement comprising may include providing one or more of the cement compositions as described in this disclosure that include 3DG carbons and mixing with water, where the water to cement ratio by weight may be approximately between about 0.3 and approximately 0.5.

[0025] In some implementations, an example liquid admixture may include a carbon- based material including three-dimensional graphene flakes (“3DG carbons”), wherein the 3DG carbons include nano-silica surface functional groups, a surfactant, and water. In some instances, a concentration of 3DG carbons in the liquid admixture may be about 100 g / liter.

[0026] In some implementations, the three-dimensional graphene flakes may include one or more few layer graphene (“FLG”), or many layer graphene (“MLG”). In some instances, the three-dimensional graphene flakes may include between about 5 and about 15 graphene layers in a stacked orientation.

[0027] In some implementations, the 3DG carbons may be characterized by a Raman spectroscopy signature having an ID / IGratio of less than 1. In some instances, the 3DG carbons may be characterized by a Raman spectroscopy signature having an I2D / IGratio of less than 1.

[0028] In some implementations, an average size of the 3DG carbons in the liquid admixture may be between about 90 nm and about 110 nm. In some other implementations, an example surfactant may include one or more of Ethacryl G or sodium dodecylbenzenesulfonate (SDBS).

[0029] In some implementations, another example liquid admixture may include a carbon-based material including three-dimensional graphene flakes (“3DG carbons”), wherein the 3DG carbons include nano-silica surface functional groups and oxygen functional groups, and water. The liquid admixture may be free of surfactants. In some instances, a concentration of 3DG carbons in the liquid admixture may be between about 3 g / liter and about 5 g / liter. In some implementations, the three-dimensional graphene flakes may include one or more few layer graphene (“FLG”), or many layer graphene (“MLG”). In some instances, the three-dimensional graphene flakes may include between about 5 and about 15 graphene layers in a stacked orientation. In some implementations, the 3DG carbons may be characterized by a Raman spectroscopy signature having an ID / IG ratio of less than 1. In some instances, the 3DG carbons may be characterized by a Raman spectroscopy signature having an I2D / IG ratio of less than 1. In some implementations, an average size of the 3DG carbons in the liquid admixture may be between about 90 nm and about 110 nm. In some other implementations, an example surfactant may include one or more of Ethacryl G or sodium dodecylbenzenesulfonate (SDBS).

[0030] The example liquid admixtures described above may be used in concrete formulations including formulations associated with high performance concrete and ultra-high performance concrete, and packaged concrete mixtures. Examples of packaged concrete include Quikrete®. An example liquid admixture may also be used in quick set cement formulations, for example Rapid Set®.

[0031] In some implementations, an example mortar composition may include any one of the cement compositions described in this disclosure and sand.

[0032] In some implementations, an example concrete composition may include any one of the cement compositions including 3DG carbons as described in this disclosure, and one or more of fine aggregates or coarse aggregates. In some instances, a compressive strength of concrete measured using ASTM C39 at a hydration period of 28 days may be at least about 1 MPa.

[0033] In some other implementations, the compressive strength of an example concrete formulation including 3DG carbons may be between about 1 MPa and about 55 MPa. Accordingly, the example concrete may be categorized as standard concrete.

[0034] In some implementations, the compressive strength of an example concrete formulation including 3DG carbons may be between about 30 MPa and about 100 MPa. Accordingly, the example concrete may be categorized as self-compacting concrete.

[0035] In some other implementations, the compressive strength of an example concrete formulation including 3DG carbons may be between about 40 MPa and about 130 MPa. Accordingly, the example concrete may be categorized as high strength concrete.

[0036] In some other implementations, the compressive strength of an example concrete formulation including 3DG carbons may be greater than 150 MPa. Accordingly, the example concrete may be categorized as ultra-high performance concrete.

[0037] In some implementations, an example cement formulation may include cementitious binder with a water to cementitious binder ratio of between about 0.15 and 0.3. In some instances, the cementitious binder may include Portland cement and a pozzolan.

[0038] In some implementations, an example cement formulation may include cementitious binder with a water to cementitious binder ratio of between about 0.15 and about 0.3. In some instances, the cementitious binder includes Portland cement, a pozzolan (for example, a material including blast furnace slag, fly ash, metakaolin, silica fume, or other similar nonlimiting example materials), and steel fiber.

[0039] In some implementations, an example cement formulation may include cementitious binder with a water to cementitious binder ratio of between about 0.15 andabout 0.3. In some instances, the cementitious binder may include Portland cement, a pozzolan (e.g., blast furnace slag, fly ash, metakaolin, silica fume, or other similar nonlimiting example materials), and a polymeric fiber (e.g., ultrahigh molecular weight polyethylene, polypropylene, polyethylene, polyvinyl alcohol, or other similar nonlimiting example polymeric fibers).

[0040] In some implementations, an example cement formulation may include cementitious binder with a water to cementitious binder ratio of between about 0.15 and about 0.3. In some instances, the cementitious binder may include Portland cement, a pozzolan (e.g., blast furnace slag, fly ash, metakaolin, silica fume, or other similar nonlimiting example materials), and carbon fiber.

[0041] In some implementations, an example cement formulation may include cementitious binder with a water to cementitious binder ratio of between about 0.15 and 0.3. In some instances, the cementitious binder may include Portland cement, a pozzolan (e.g., blast furnace slag, fly ash, metakaolin, silica fume, or other similar nonlimiting example materials), and plant fiber.

[0042] In some implementations, an example cement formulation may include cementitious binder with a water to cementitious binder ratio of between about 0.15 and about 0.3. In some instances, the cementitious binder may include Portland cement, a pozzolan (e.g., blast furnace slag, fly ash, metakaolin, silica fume, or other similar nonlimiting example materials), and basalt fiber.

[0043] In some implementations, an example cement formulation may include cementitious binder with a water to cementitious binder ratio of between about 0.15 and about 0.3. In some instances, the cementitious binder may include Portland cement, a pozzolan (e.g., blast furnace slag, fly ash, metakaolin, silica fume, or other similar nonlimiting example materials), and glass fiber.

[0044] Details of one or more implementations of the subject matter described in this disclosure are set forth in the accompanying drawings and the description below. Other features, aspects, and advantages will become apparent from the description, the drawings, and the claims. Note that the relative dimensions of the following figures may not be drawn to scale.BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Figure 1A shows a schematic diagram of a mesoporous nanoparticle in 3DG carbons, according to some implementations.

[0046] Figure 1B shows a diagram of nano-confinement of a dopant in the space between orthogonally joined graphene platelets of Figure 1A, according to some implementations.

[0047] Figure 2A shows another diagram of example 3-dimensional graphene (3DG) carbons, according to some implementations.

[0048] Figure 2B shows a transmission electron microscope (TEM) micrograph of 3DG carbons, according to some implementations.

[0049] Figure 2C shows a scanning electron microscope (SEM) micrograph of 3DG carbons, according to some implementations.

[0050] Figure 3 shows a diagram of calcium-aluminosilicate hydrates including polymerized fibrous materials supported by 3DG carbons, according to some implementations.

[0051] Figure 4 shows a box plot representation of compositions of pyroclastic ash supplementary cementitious material (SCM) with known pozzolanic activity.

[0052] Figure 5A shows micrographs of 3DG carbons functionalized with spherical nano- silica particles and “string of pearls” clusters, according to some implementations.

[0053] Figure 5B shows a scanning electron microscopy (“SEM”) micrograph of 3DG carbons functionalized with rod-shaped nano-silica particles and clusters, according to some implementations.

[0054] Figure 6A shows a SEM / EDS micrograph of 3DG carbons prior to functionalization, according to some implementations.

[0055] Figures 6B–6D show elemental composition maps measured during SEM / EDS analysis of 3DG carbons after nano-silica functionalization, according to some implementations.

[0056] Figure 7A shows elemental composition intensity (counts) measured during SEM / EDS analysis of 3DG carbons functionalized with nano-silica, according to some implementations.

[0057] Figure 7B shows a box plot of elemental composition distribution measured by SEM / EDS analysis of various 3DG carbons functionalized with nano-silica, according to some implementations.

[0058] Figure 8 shows a thermogram of example cement compositions functionalized with nano-silica, according to some implementations.

[0059] Figure 9A shows a diagram of an example primary carbon particle in 3DG carbons, according to some implementations.

[0060] Figure 9B shows a TEM image of primary particles and aggregates in 3DG carbons, according to some implementations.

[0061] Figure 9C shows a TEM image of 3DG carbon agglomerates, according to some implementations.

[0062] Figure 10 shows a diagram of another example primary carbon particle in 3DG carbons, according to some implementations.

[0063] Figure 11 shows a plot comparing the compressive strength of mortar samples including cement with varying 3DG carbon carbons, according to some implementations.

[0064] Figure 12 shows a plot comparing the early age compressive strength of mortar samples including cement with varying 3DG carbon carbons according to some implementations.

[0065] Figure 13 shows a plot comparing the water absorption rate of mortar samples including cement with varying amounts of 3DG carbons, according to some implementations.

[0066] Figure 14 shows a plot comparing the charge passed through mortar samples during rate of chloride ion penetration tests (“RCPT”) including cements with varying amounts of 3DG carbons, according to some implementations.

[0067] Figure 15 shows a plot comparing the non-steady state chloride migration coefficient during rate of chloride migration (“RCM”) tests through mortar samples including cements with varying amounts of 3DG carbons, according to some implementations.

[0068] Figure 16 shows a plot comparing the early age compressive strength of mortar samples including cement with varying amounts of 3DG carbons, according to some implementations.

[0069] Figure 17 shows a plot comparing heat flow calorimetric patterns associated with hydrating cement samples with varying amounts of 3DG carbons, according to some implementations.

[0070] Figure 18A shows a plot comparing heat flow calorimetric patterns associated with hydrating cement samples with varying amounts of 3DG carbons and ozone oxidized 3DG carbons, according to some implementations.

[0071] Figure 18B shows a plot comparing cumulative heat release over time associated with hydrating cement samples with varying amounts of 3DG carbons and ozone oxidized 3DG carbons, according to some implementations.

[0072] Figure 19A shows a plot comparing heat flow calorimetric patterns associated with hydrating cement samples with varying amounts of ozone oxidized 3DG carbons, according to some implementations.

[0073] Figure 19B shows a plot comparing cumulative heat release over time associated with hydrating cement samples with varying amounts of ozone oxidized 3DG carbons, according to some implementations.

[0074] Figure 20A shows a plot comparing heat flow calorimetric patterns associated with hydrating cement samples including 3DG carbons surface functionalized with nano- silica, according to some implementations.

[0075] Figure 20B shows a plot comparing cumulative heat release over time associated with hydrating cement samples including 3DG carbons surface functionalized with nano- silica, according to some implementations.

[0076] Figure 21 shows a plot comparing the compressive strength of concrete including 3DG carbons with that of a reference concrete as a function of time, according to some implementations.

[0077] Figure 22 shows another plot comparing the compressive strength of concrete including 3DG carbons with that of a reference concrete as a function of time, according to some implementations.

[0078] Figure 23 shows another plot comparing an increase in compressive strength of concrete including 3DG carbons relative to that of a reference concrete as a function of time, according to some implementations.

[0079] Figure 24 shows a plot comparing particle size distribution of 3DG carbons in a liquid admixture as a function of time, according to some implementations.

[0080] Figure 25A shows a scanning transmission electron microscopy (“STEM”) micrograph of 3DG carbons, according to some implementations.

[0081] Figure 25B shows an electron energy loss spectroscopy (“TEM-EELS”) micrograph of 3DG carbons, according to some implementations.

[0082] Like reference numbers and designations in the various drawings indicate like elements.DETAILED DESCRIPTION

[0083] The following description is directed to some example implementations for the purpose of describing the innovative aspects of this disclosure. However, a person having ordinary skill in the art will readily recognize that the teachings herein can be applied in a multitude of different ways. The described implementations can be implemented in cement compositions for a variety of applications and may be tailored to compensate for various performance related deficiencies. As such, the disclosed implementations are not to be limited by the examples provided herein, but rather encompass all implementations contemplated by the attached claims. Additionally, well-known elements of the disclosure will not be described in detail or will be omitted so as not to obscure the relevant details of the disclosure.

[0084] Various aspects of the novel compositions and methods are described more fully herein with reference to the accompanying drawings. These aspects are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art. Although some examples and aspects are described herein, many variations and permutations of these examples fall within the scope of the disclosure. Although some benefits and advantages of the various aspects are mentioned, the scope of the disclosure is not intended to be limited to benefits, uses, or objectives. The detailed description and drawings are merely illustrative of the disclosure rather than limiting, the scope of the disclosure being defined by the appended claims and equivalents thereof.

[0085] Ordinary Portland cement (“OPC”) is produced by calcining limestone (CaCO3) with clay (aluminosilicates) in a kiln at about 1500oC to form a sintered product commonly known as clinker. Portland cement is used as a cementitious material (binder) in cement products including concrete. ASTM standard specification (ASTM C150) requires that Portland cement “must have the following chemical compositions: aluminum oxide, ferric oxide, magnesium oxide, sulfur trioxide, tricalcium silicate (“C3S”), dicalcium silicate (“C2S”), tricalcium aluminate (“C3A”), and tetracalcium aluminoferrite.” When mixed with water, the calcium silicates and aluminates are hydrated via several hydration and gelation reactions to primarily form calcium-silicate-hydrate (“CSH”) paste, which gradually bonds sand and gravel particles in concrete together and hardens to form a solid water-resistant product via a process known as setting. After initial setting, concrete continues to harden and develop its mechanical strength over a period of about 30 days. About less than 5 wt% gypsum (hydrated calcium sulfate) may be added to clinker and ground to fine powder in aball mill. Gypsum is added primarily to retard the setting time of cement by slowing down the hydration rates of the C2S, C3S and C3A, and more importantly, the exothermic hydration of C3A by preventing “flash setting.”

[0086] In addition to forming CSH, hydration typically forms a byproduct known as Portlandite, which is composed of calcium hydroxide (“CH”). Portlandite does not have cementitious properties and may cause an undesirable increase in the permeability of concrete to water, which reduces the mechanical strength of concrete. To mitigate this effect, supplementary cementitious materials (“SCM”) commonly known as pozzolans may be added to Portland cement or concrete prior to hydration, to react with CH and water during hydration via the pozzolanic reaction, which also has the beneficial effect of forming additional CSH cementitious compounds.

[0087] An SCM may be defined as “an inorganic material that contributes to the properties of a cementitious mixture through hydraulic or pozzolanic activity, or both.” See, for example, ASTM 2015, Paper FHWA-HIF-16-001, U.S. Department of Transportation. The type and amount of SCMs may be varied to reduce the amount of Portland cement in concrete (or increase the replacement levels of cement), without sacrificing mechanical strength. SCMs may contribute to the formation of cementitious materials by both hydraulic activity and pozzolanic activity. SCMs (and cements) that have hydraulic properties, harden during hydration, and that hardening process does not require drying. SCMs with pozzolanic activity require both water and CH as reactants to form CSH.

[0088] As previously described, undesirable CH produced by hydraulic activity (for example, hydration of Portland cement), may be consumed during pozzolanic activity provided by SCMs to produce additional amounts of cementitious compounds like CSH. Examples of SCMs may include fly ash (byproduct of coal fired furnaces), blast furnace slag, silica fume, and natural pozzolans like metakaolin. Other SCMs including slag may exhibit hydraulic activity and produce cementitious compounds during hydration. Slag cement does not exhibit pozzolanic activity but consumes CH by binding alkalis in its hydration products. Therefore, although it is a hydraulic cement, slag cement provides the benefits of a pozzolan. SCMs are also used to improve concrete performance in its fresh and hardened state and also to improve the workability, durability and strength of concrete.

[0089] The amount of fly ash in concrete may vary from 5% to 65% by mass of the cementitious materials. The amount of slag may vary from 20% to 70% by mass of the cementitious materials. The amount of silica fume may vary from 5% to 12% by mass ofcementitious materials. Natural pozzolans that exhibit pozzolanic activity may include metakaolin, calcined shale, or clay. The amount of metakaolin may vary from 5% to 70% by mass of cementitious materials. Higher amounts (percentage by mass) of calcined shale or clay may be used. See, for example, paper CIP30–SCMs, National Ready Mixed Concrete Association, 2000. While fly ash and slag increase initial set time and setting time of concrete, silica fume accelerates the hydration of Portland cement by providing nucleation sites for the formation of hydration products like CSH.

[0090] The cement industry contributes to about 8% of global greenhouse gas (CO2) emissions. About 90% of these emissions are produced during the high temperature calcination process of limestone and clay materials at amounts of about 0.8 tons CO2per ton of OPC, which includes the amount of CO2produced by combustion of fuels used to heat the kilns. Accounting for CO2 emissions from quarry-to-point-of-use, approximately 1 ton of CO2 is produced per ton of OPC. Therefore, considerable research and development has been directed to reduce the amount of Portland cement in concrete and increase the replacement levels of cement. As described above, using SCM additives is one approach to increase the replacement levels of cement and realize reductions in CO2 emissions.

[0091] Researchers at Exeter University (United Kingdom) have reported that graphene additives to cement may increase the replacement level of cement in concrete by as much as 50% and lead to significant reduction in CO2 emissions. Small amounts of graphene additives also increase the mechanical strength, durability, and the water resistance of concrete. Graphene is a single layer of carbon atoms arranged in a hexagonal structure. Atomically thin shards of graphene may be suspended in water during mixing concrete. Additionally, researchers at the University of Manchester (United Kingdom) have reported that graphene not only provides mechanical strength, but also acts as a catalyst surface for initiating hydration reactions, which provides a finished cement product with improved strength, durability, and corrosion resistance.

[0092] PureGraph®(First Graphene, United Kingdom) is a graphene nanoplatelet powder additives with particle size (Dv50) from 5 µm to 50 µm. The graphene nanoplatelets are produced by electrochemical exfoliation of graphite. The powders are not aggregated and may be dispersed in water and added to cement. Reports suggest that 0.01% to 0.05% of graphene nanoplatelet powders in cement compositions provide the same or better mechanical strength as Portland cement in cementitious products while reducing the amount of clinker required by about 20% to 30%. That is, the replacement level of OPC is about20% to 30%. As such, CO2emission reduction of about 20% is possible even with small amounts of graphene additives.

[0093] Reports suggest that graphene physically and chemically interacts with cementitious binders and improves adhesion between the graphene basal planes and cement gel by Van der Waals forces, which reinforces the hydrated structure by preventing cracks from developing at a nanoscale. Changes in porosity and hydration at the graphene-cement interface have also been observed. When used as a water-based admixture in typical cement- based mortar at dosing levels of less than 0.1%, graphene was found to increase compression strength by 34% increase in and tensile strength by 7%. However, graphene produced by exfoliation of graphite is an expensive boutique additive. Reports suggest that in volumes approaching about 5 tons, the price range of the graphene nanoplatelet powders may be about $250 / kg–$300 / kg, which is about 2000x the U.S. price of Portland cement (of about $125 / ton). Less expensive additives and cement compositions which offer higher replacement levels of Portland cement, and which lead to reduced setting time without reduction in mechanical strength are required.

[0094] In some implementations, an example cement composition may include ordinary Portland cement (“OPC”), one or more SCM additives, and 3DG carbons as additives or fillers. Any one of the SCMs or combination of SCMs previously described in this disclosure may be used to form cement compositions in accordance with aspects of the present disclosure. The amount of 3DG carbons may be between approximately 0.05% by weight of cement (bwoc) and 2% bwoc. The 3DG carbons may include aggregates of carbon nanoparticles having graphene nanoplatelets with an interconnected porous network. The 3DG carbons may include graphene nanoplatelets orthogonally joined to each other to form a 3D porous graphene scaffold structure. The graphene nanoplatelets may include one or more of single layer graphene (“SLG”), few layer graphene (FLG), or many layer graphene (“MLG”).

[0095] Figure 1A shows a schematic diagram of a mesoporous carbon nanoparticle 100A in 3DG carbons, according to some implementations. The 3DG carbons including agglomerates of nanoparticle 100A graphene flakes (as described below) may be produced by high throughput, low-cost, cracking of a hydrocarbon gas (including natural gas) in an atmospheric microwave plasma reactor. An example microwave plasma reactor that can be used to produce the 3DG carbons is disclosed in commonly-owned U.S. Pat. No. 9,767,992, which is incorporated by reference herein in its entirety. For example, 3DG carbons may beformed in-flight and grown by adding additional carbon-based materials derived from incoming carbon-containing gas within a microwave-plasma reaction chamber.

[0096] A plurality of primary carbon nanoparticles 100A produced by one or more methods including thermal cracking of a hydrocarbon gas or source material may be coalesced or joined to form aggregates of primary particles. An aggregate may be considered to be a discrete, colloidal entity that is the smallest dispersible unit composed of coalesced primary carbon nanoparticles. A primary carbon particle may be considered to be a spheroidal shaped, non-discreet component of an aggregate that is separable from the aggregate only by fracturing. The primary carbon particles may be connected together by one or more of Van der Waals forces, covalent bonds, ionic bonds, metallic bonds, or by other physical or chemical interactions. Additionally, a plurality of aggregates may be considered to be agglomerates. Since aggregates of at least 1 µm in size may be considered to be agglomerates, the term “aggregates” also includes “agglomerates” in this disclosure. A carbon nanoparticles aggregate may be characterized by a principal dimension (diameter, length, width) of greater than about 1 µm.

[0097] The carbon nanoparticles 100A may be or may include three-dimensional (“3D”) multi-modal mesoporous carbon nanoparticles. A mesoporous material, as generally understood and as referred to herein, includes a material containing pores with diameters between 2 nm and 50 nm, according to IUPAC nomenclature. For the purposes of comparison, IUPAC defines microporous material as a material having pores smaller than 2 nm in diameter and defines macroporous material as a material having pores larger than 50 nm in diameter. In some instances, mesoporous carbon particle 100A may be characterized by a three-dimensional (“3D”) hierarchical porous structure including pores 110. In some aspects, at least a portion of the hierarchical porous structure may further define a 3D open porous scaffold structure 120.

[0098] The nanoparticle 100A may include one or more interconnected bundles 130 of electrically conductive graphene platelets or sheets. Each interconnected bundle 130 may include one or more stacks 132 of graphene sheets. Each stack 132 may include a plurality of graphene layers 136 that are generally stacked horizontally as more clearly shown in stack 140. One or more stacks 132 of graphene sheets 136 may be arranged to form a 3D porous scaffold structure 120. That is, a plurality of stacks 132 of electrically conductive graphene layers 136 may be sintered together to define the 3D open porous scaffold structure 120 (which includes mesopores 110 in the example of Figure 1A). In some implementations, oneor more of the stacks 132 may be connected substantially orthogonal to each other. The open porous scaffold structure 120 may be configured to provide electrical conduction between contact points (not shown for simplicity) of the stacks of graphene sheets 136. In some implementations, each graphene layer 136 may be characterized by a diameter or linear dimension (“La”) of between about 50 nm to about 200 nm. The graphene stack 132 may include few layer graphene (“FLG”), which may be composed of 5 to 15 layers of graphene.

[0099] A plurality of primary carbon nanoparticles 100A may be coalesced or joined to form aggregates of primary particles. In this disclosure, 3DG carbons may include aggregates or agglomerates of mesoporous nanoparticles 100A. In some implementations, the example 3DG carbons described herein may be characterized by a Brunauer–Emmett–Teller (“BET”) surface area measured using nitrogen gas of about 50 to 300 m2 / g. In some implementations, the 3DG carbons may be characterized by a graphene to amorphous carbon ratio of between about 1% and 95%. In some implementations, the 3DG carbons may be characterized by a carbon purity of at least 99.9%. The 3DG carbons may be characterized by an electrical conductivity of between about 500 S / m and about 20,000 S / m when compressed at pressure of about 12,000 pounds per square inch (“psi”). Without being bound by any particular theory, the 3DG carbons including mesoporous nanoparticles as described herein may improve the mechanical strength of a cementitious product.

[0100] In some implementations, dopants including one or more of sulfates, silicates, or alkalis that beneficially impact cement hydration processes may be disposed on the surface of 3DG carbons including mesoporous nanoparticles 100A, may be micro-confined in the pores of the open porous scaffold structure 120, or may be nano-confined in the open porous scaffold structure 120.

[0101] Figure 1B shows a diagram 100B of nano-confinement of a dopant in the pores 110 disposed between orthogonally joined graphene layers 136, according to some implementations. In some instances, the dopants may be nano-confined in the 3D open porous scaffold structure 120 and released out as a function of time. Timed-release of nucleating agents may be tuned to impact the acceleration of the pozzolan reaction after the formation of Portlandite from the reaction of anhydrous calcium silicate with water. 3DG carbons including mesoporous nanoparticles 100A may also provide a flexible scaffold-type structure to manage material expansion and mitigate crack formation during hydration and curing of cement. In some configurations, the stack 132 may include one or more of singlelayer graphene (“SLG”), few layer graphene (“FLG”) defined as ranging from 5 to 15 layers of graphene, or many layer graphene (“MLG”).

[0102] In some implementations, mesoporous nanoparticles 100A may include a plurality of interconnected crinkled 3D graphene sheets, a plurality of non-hollow carbonaceous spherical particles (“NHCS”), flat graphene, wrinkled graphene, a plurality of carbon nanotubes (“CNTs”), or a plurality of carbon nano-onions (“CNOs”). In some implementations, mesoporous nanoparticles 100A may include wavy or flexible graphene layers that resemble crinkled paper and may be produced using microwave processes. The graphene layers may be flexible as they may be fused with each other at sp3type defects in the sp2graphene lattice structure.

[0103] Figure 2A shows a diagram of 3DG carbons 201 having porous interconnected graphene nanoplatelets (“GNP”) and a scaffolded structure, according to some implementations. Figure 2B shows a TEM micrograph 202 of the 3DG carbons 201, according to some implementations. As shown, the 3D few-layer graphene (“FLG”) flakes 201’, may be seen at 50 nm scale. FLG may refer to about 10 layers of graphene generally configured in a stacked orientation. Those skilled in the art will appreciate that the micrographs are shown by way of example only, and that other scales may exist without departing from the scope and spirit of the present implementations.

[0104] Figure 2C shows a SEM micrograph of 3DG carbons 203, according to other implementations. In some instances, plasma-based processing conditions applied or performed in a reactor including a microwave reactor may be adjusted with a high degree of tunability to achieve 3DG carbons and graphene-on-graphene densification to yield the complex 3DG carbons 203. The 3DG carbons 203 may be surface etched using methods including CO2etching to create pores on the external surface of the agglomerates 203’ and to increase the surface area of the 3DG carbons.

[0105] The 3DG carbons described herein and characterized using Raman spectroscopy show a high degree of order and uniformity of structure. In this disclosure, “graphene” refers to an allotrope of carbon in the form of a two-dimensional, atomic-scale, hexagonal lattice in which one atom forms each vertex. The carbon atoms in graphene may be sp2hybridized carbon atoms. Additionally, graphene has a Raman spectrum with two main peaks: a G- mode at approximately 1580 cm-1and a D mode at approximately 1350 cm-1(when using a 532 nm excitation laser). The 3DG carbons may be characterized by a Raman spectroscopy signature having an ID / IG ratio between approximately 0.95 and approximately 1.05.

[0106] Figure 3 shows a diagram of calcium-aluminosilicate hydrates 300 including polymerized fibrous materials 301 supported by 3DG carbons 304, according to some implementations. Without being bound by any particular theory, hydration of ordinary Portland cement (“OPC”) including gypsum (calcium sulfate dihydrate) may form random needle-like ettringite (calcium sulfo-aluminate), tobermorite (calcium silicate hydrate) and calcium-aluminosilicate hydrates (“CASH”) in the form of entangled and branched polymerized fibrous material 301 of silicates and aluminates. Polymerized fibrous material 301 may include polymerized amorphous alumino-silicates 302 and crystalline alumino- silicates 303. 3DG carbons 304 may be used as fillers or seeding agents to anchor or serve as a “bridging agent” between polymerized CASH fibers, thereby leading to in higher compressive and tensile strength and greater resistance to fracture during the setting of the hydrated cementitious product. The high surface area of 3DG carbons 304 may provide a high density of nucleating sites for CSH or CASH, which may then grow and polymerize to form fibrous material 301.

[0107] By kinetically controlling the hydration and authigenic formation of entangled, needle-like crystalline phases in the cementitious matrix, elasticity and toughness may be improved over conventional concrete. 3DG carbons 304 used in example cement compositions may further reduce the permeability of the hydrated cementitious product over and above the reduction in permeability possible with the use of only a pozzolan as SCM. 3DG carbons 304 when used as additives or fillers may also reduce shrinkage on cooling the cementitious product because 3DG carbons exhibit negative thermal expansion. That is, the 3DG carbons 304 increase in size when cooling and decrease in size when heating. In contrast, cementitious products without any 3DG carbons 304 are characterized by positive thermal expansion. Therefore, by varying the amount of 3DG carbons 304 used as fillers or additives, crack formation in the cementitious product due to repetitive ambient temperature thermal cycling may be reduced.

[0108] In some implementations, an example cement composition may include ordinary OPC, volcanic or pyroclastic (pozzolana) ash or metakaolin as a SCM at about 70% replacement level of OPC, and 3DG carbons. That is, about 70% of OPC by mass may be replaced by pyroclastic (pozzolana) ash. The replacement level of OPC with metakaolin may be greater than 70%. In this example cement composition, metakaolin having varying amounts of aluminosilicates may be considered to be an SCM with pozzolanic activity. OPC exhibits high autogenous temperature rise and corresponding high tensile shrinkage strainsduring the exothermic hydration process. In contrast, metakaolin including aluminosilicates, hydrate or gelate at lower temperatures and lower rates thereby reducing mechanical strains and micro-cracking and producing a more elastic and toughened cementitious product with higher chemical resistance, lower permeability to water and other chemicals. Without being bound by any particular theory, the 3DG carbons and functionalized 3DG carbons serve as nucleating agents for CSH and CASH formation, which helps to realize the 70% replacement of OPC in the example Portland cement / SCM blends as disclosed herein. Table 1 summarizes the anticipated benefits of cement compositions with 3DG carbons as fillers or additives.Table 1. Summary of benefits of cement composition including 3DG carbons

[0109] Figure 4 shows a box plot representation 400 of compositions of pyroclastic ash SCM with known pozzolanic activity. Pyroclastic ashes or pumices materials result from explosive eruptions and show higher pozzolanic activity. The eruption type largely depends on the magma viscosity which is related to the “acidity” (i.e., SiO2 content) of the magma. In general, more siliceous magma produces more explosive volcanism and products with better pozzolanic properties. Coarser highly vesicular pyroclastic material forms pumice-type deposits. Finely divided materials are transported further away from the volcanic source and are deposited as ash layers. Silica (SiO2) content in most natural pumices and ashes fall in the intermediate range (approximately 50–70 wt% SiO2) to acidic range (greater than approximately 70 wt% SiO2). The pyroclastic ash may include between approximately 50 wt% and approximately 70 wt% SiO2, between approximately 10 wt% and 20 wt% Al2O3, and less than approximately 10 wt% each of Fe2O3 and MgO. The loss on ignition (“LOI”) of the pyroclastic ash may be less than approximately 10 wt%.

[0110] The total alkali content may vary depending upon the regional type of volcanic activity and may reach at least approximately 11 wt% on an anhydrous basis in Neapolitan pozzolans. Pyroclastic ashes may contain Fe2O3, CaO, and MgO in minor proportions. Loss on ignition (“LOI”) may exceed approximately 10 wt% in some ashes. See, for example, Snellings et al., “Supplementary Cementitious Materials,” Reviews in Mineralogy and Geochemistry, May 2012, which is incorporated herein in its entirety.

[0111] As previously described, the addition of gypsum to OPC prevents flash setting during hydration; however, gypsum retards the setting of the cementitious product. 3DG carbons may be functionalized using various methods to include specific dopants. 3DG carbons may include sulfur or sulfates anchored on the surface as shown in the example of Figure 3 or may be micro-confined within the interconnected open porous scaffold structure 120 (as shown in Figure 1A) or nano-confined in the scaffold structure formed by orthogonally joined graphene nanoplatelets (as shown in Figure 1B). Sulfur compounds may be released in a controlled manner, that is, time released, into the CSH or CASH matrixduring hydration facilitated by the tortuous interconnected porous network of the 3DG carbons. Sulfur-doped 3DG carbons enable regulated, local and distributed introduction of sulfate during the hydration process, which in turn enables control of the hydration rate and mitigates fast hydration, or flash set which adds stiffness. Controlling the hydration rate of cement can enhance elasticity and toughness without compromising the strength of the cementitious product.

[0112] Similarly, release of alkalis including sodium or potassium from alkali–doped 3DG carbons may facilitate the formation of sodium aluminosilicate hydrate (“NASH”) chains, which in turn, may cross-link or entangle with CASH chains to enable strain hardening and strengthening of the cement matrix. Sodium hydroxide may behave as an alkali activator to reduce cement setting time and improve initial mechanical strength of the cement. Accordingly, in addition to sulfur, 3DG carbons may be doped with sodium, to offer synergistic benefits during initial hydration and setting processes.

[0113] In some implementations, an example cement composition may include ordinary Portland cement (“OPC”), volcanic or pyroclastic (pozzolana) ash with about 70% replacement level of OPC, and chemically functionalized 3DG carbons. An example cement composition may include 3DG carbons surface functionalized with an alkali including sodium. Another example cement composition may include 3DG carbons functionalized with sulfur oxide (S–O) species. 3DG carbons may be functionalized with elements including oxygen, nitrogen, silicon, or hardening agents.

[0114] 3DG carbons may be functionalized in situ – that is, within the reactor during the production of 3DG carbons. In some implementations, 3DG carbons may be functionalized using separate post-production processing steps. For example, 3DG carbons may be treated with ozone to surface oxidize the carbon. Harnessing the full potential of 3DG carbons requires uniform dispersion of 3DG carbons in hydrophilic and polar systems, for example in water, to mitigate agglomeration of the 3DG carbons within the cement, mortar or concrete formulations. Agglomeration or clumping may reduce the beneficial enhancement in mechanical properties due to the addition of 3DG carbons in cement, mortar, or concrete formulations. Surface functionalization of 3DG carbons may disperse, size separate, and stabilize the 3DG carbons in a hydrophilic system. In some aspects, the hydrophilic system associated with cement, mortar or concrete formulations may be free of surfactants. Ozone oxidation may produce oxygen-containing functional groups in and / or on the surfaces of 3DG carbons described herein. The oxygen containing functional groups on the 3DG carbons mayinclude one or more of epoxide (C–O–C, two carbons and oxygen forming a three-membered ring structure), hydroxyl (–OH), ether (C–O–C), ketone (O–C=O), or carboxylic acid (– COOH) groups. The approximate oxygen content associated with the oxygen containing functional groups and measured using instrumental gas analysis (IGA–O) may be between about 1 wt% and about 25 wt%. The approximate atomic content of oxygen (O)-containing functional groups may be between about 10 at% and 50 at%. Using X-ray photoelectron spectroscopy (“XPS”) composition measurements, the C–O–C functional group concentration on 3DG carbons may be between about 45 at% and 55 at%. The C–C functional groups concentration may be between about 45 at% and about 55 at% and the O- C=O functional group concentration may be between about 5 at% and about 10 at%. One or more of the example functional groups described herein may be disposed as surface functional groups on 3DG carbons. In other implementations, one or more of the example functional groups described herein may be disposed within the porous structure of the 3DG carbons.

[0115] In some implementations, 3DG carbons may be subjected to ozone oxidation in a fluidized bed reactor. A reactive ozone-treated oxidant gas may fluidize a bed of 3DG carbons at suitable process conditions to generate various oxygen-containing species or functional groups (as described above) on the surface of the 3DG carbons. The surface oxygen groups may mitigate clumping of the 3DG carbons in the hydrophilic system associated with cement, mortar or concrete formulations and may also enhance the reactivity of the 3DG carbons during post-processing or additional surface functionalization. In some implementations, the 2D / G ratio associated with the Raman spectra of ozone treated 3DG carbons may be about 0.7, which suggests that the graphene flakes in the 3DG carbons include multi-layer graphene. Additional properties associated with ozone functionalized graphene is described in Example 14 in this disclosure.

[0116] In some other implementations, the 3DG carbons including oxygen functional groups as described above may be further postprocessed to functionalize the oxidized surface of the carbon with silane through a modification of the Stobbe colloidal silica synthesis. Furthermore, the surfaces of 3DG carbons may be functionalized with silica, oxygen or nitrogen containing species which form bonds with polymers of the cementitious matrix, thus improving adhesion and providing strong binding to enhance the strength of cementitious product.

[0117] In some implementations, the 3DG carbons may be used without any post- production processing steps. In other implementations, the 3DG carbons may be subject to post-product processing steps. Example post-production processing steps may include one or more of mechanical processing steps including ball milling, grinding, attrition milling, micro fluidizing, or other processes to reduce particle size. Post-production processing steps may also include one or more exfoliation processes including sheer mixing, chemical etching, oxidizing (e.g., Hummer method), thermal annealing, doping by adding elements during annealing (e.g., sulfur, nitrogen), steaming, filtering, or lyophilizing, or other processes. Some other examples of post-production processing may include sintering processes including one or more of spark plasma sintering (“SPS”), direct current sintering, microwave sintering, or ultraviolet (“UV”) sintering, which may be conducted at high pressure and temperature in an inert gas. In some other implementations, multiple post-production processing methods may be used in any combination to achieve desired physical and chemical properties of the 3DG carbons. For example, post-production processing may yield functionalized 3DG carbons as disclosed herein.

[0118] In some implementations, the 3DG carbons may be subjected to post-production thermal annealing or sintering in an inert environment including nitrogen or argon and at elevated temperatures, and at atmospheric pressure, or under vacuum. Post-production processing temperatures may range from approximately 500°C to 2500°C, or from approximately 500°C to 1500°C, or from approximately 800°C to 1500°C, or from approximately 800°C to 1200°C, or from approximately 800°C to 1000°C, or from approximately 2000°C to 2400°C, or approximately at 800°C, or approximately at 1000°C, or approximately at 1500°C, or approximately at 2000°C, or approximately at 2400°C.

[0119] In some implementations, 3DG carbons may be doped with silicon during the production of 3DG carbons in a microwave reactor. Vaporized silicon precursors including one or more of hexamethyl disiloxane (HMDSO), hexamethyldisilazane (HMDSN), or other similar precursors, may be injected into the microwave reactor along with a hydrocarbon feedstock to produce 3DG carbons functionalized with silicon.

[0120] In some other implementations, 3DG carbons may be surface functionalized with silica containing functional groups including nano-silica or calcium-silicate hydrate (C-S-H or CSH). In some implementations, 3DG carbons may be surface functionalized with CSH groups or nanoparticles by treating with calcium nitrate – Ca(NO3)2 – and sodium silicate – Na2SiO3. Without being bound by any particular theory, CSH nanoparticles may be disposedat carboxylate (RCOO⁻) sites on the surface of the 3DG carbons. CSH nanoparticles on the surface of 3DG carbons may initiate CSH growth during hydration of cement. Additionally, CSH nanoparticles may also be docked or attached to graphene in 3DG carbons. Accordingly, CSH nanoparticles may also provide mechanical reinforcement of the cementitious composite.

[0121] In some implementations, nano-silica particles or nano-silica clusters may be covalently grafted on the surface of the 3DG carbons. In some instances, 3DG carbons surface functionalized with oxygen, for example, using ozone oxidation as previously described herein, may be treated with silica precursors including tetraethyl orthosilicate (TEOS), or similar precursors, to initiate the formation and growth of nano-silica at the oxygen sites on the surface of oxidized 3DG carbons. In some other instances, functional groups other than oxygen containing functional groups may be first anchored on the surface of 3DG carbons to initiate the growth of silica. Additional details are provided in Example 15 in this disclosure.

[0122] Silica functionalized 3DG carbons may also accelerate the setting of cement. As previously noted with respect to CSH functionalized 3DG carbons, nano-silica particles or nano-silica clusters may also provide mechanical reinforcement of the cementitious composite while improving the dispersion of 3DG carbons to accelerate nucleation of CSH during cement hydration.

[0123] In some implementations, an example cement composition may include ordinary Portland cement (“OPC”), one or more of pyroclastic ash or metakaolin (calcined clay) or limestone as SCMs, and 3DG carbons surface functionalized with nano-silica particles or clusters. The amount of 3DG carbons functionalized with nano-silica may be less than approximately 1 wt% of the cement composition. The replacement level of OPC by the SCMs may be at least approximately 70%. The replacement level of OPC by the SCMs may be approximately 80%. An example cement composition may include approximately 20% OPC, approximately 80% SCM (metakaolin and limestone) and less than approximately 1 wt% of 3DG carbons functionalized with nano-silica. OPC may conform to European standards EN 197-1 as CEM I 42.5R or the ASTM Type I standard. Metakaolin may be supplied by Burgess Pigment Company (Sandersville, GA) as Optipozz™ metakaolin. Limestone may be supplied by Omya, Inc. (Cincinnati, OH) as Durcal 15 powders.

[0124] Without being bound by any particular theory, nano-silica particles anchored in 3DG carbons surfaces, micro-confined in the 3DG carbons, or nano-confined in the openporous scaffold structure 120 (see Figure 1A) may act as a nucleating agent for CSH formed during the hydration process. Figure 5A shows micrographs 500A and 500A’ of 3DG carbons functionalized with spherical nano-silica particles and “string of pearls” clusters, according to some implementations. That is, nano-silica particles or nano-silica particle “string of pearls” clusters 501 and 511 in 3DG carbons in the example cement compositions may function as distributed catalytic sites, and as such, as seeding agents for CSH during hydration and subsequent growth of CSH polymeric chains in the cement matrix. The hydration process may be accelerated due to improved dissolution of C3S in water and acceleration of the pozzolanic activity of the SCMs to convert CH to CSH. Further 3DG carbons functionalized with nano-silica may anchor CSH polymeric chains and may provide structural reinforcement during hydration and setting.

[0125] Figure 5B shows a scanning electron microscopy (“SEM”) micrograph 500B of 3DG carbons functionalized with nano-silica particles and rod-shaped clusters, according to some implementations. As can be seen, and in contrast to the nano-silica particles shown in micrographs 500A and 500A, nano-silica particles 512 may be disposed as tubular or rod- shaped particles and clusters on the surface of 3DG carbons. Additional details related to the hydration of cement formulations including 3DG carbons surface functionalized with nano- silica are described in Example 10 in this disclosure.

[0126] In some implementations, an example cement composition may include ordinary Portland cement (“OPC”), one or more of pyroclastic ash or metakaolin or limestone as SCMs, and 3DG carbons surface functionalized with one or more of nano-silica and oxygen. The amount of 3DG carbons functionalized with one or more of nano-silica or oxygen may be less than approximately 1 wt% of the cement composition. The replacement level of OPC may be approximately 70%. 3DG carbons doped with oxygen may also nucleate CSH seeds via covalent bonding. The replacement level of OPC by the SCMs and functionalized 3DG carbons may be approximately 80%. An example cement composite may include approximately 20% OPC, approximately 80% SCM (metakaolin and limestone) and less than approximately 1 wt% of functionalized 3DG carbons functionalized with nano-silica and / or oxygen. OPC may conform to European standards EN 197-1 as CEM I 42.5R or ASTM Type I Portland cement. Metakaolin may be supplied by Burgess Pigment Company (Sandersville, GA) as Optipozz™ metakaolin. Limestone may be supplied by Omya, Inc. (Cincinnati, OH) as Durcal 15 powders.

[0127] In some implementations, an example cement composition may include ordinary Portland cement (“OPC”), one or more of pyroclastic ash, gypsum, limestone or metakaolin as SCMs, and 3DG carbons surface functionalized with one or more of nano-silica and oxygen. The replacement level of OPC may be at least approximately 70%. The amount of 3DG carbons functionalized with one or more of nano-silica or oxygen may be less than approximately 1 wt% of the cement composition. The amount of gypsum may range from approximately 0.5 wt% to 3.5 wt% of the cement composition. A superplasticizer may be used to improve workability. Superplasticizers may be added to the cement paste in concentrations ranging from 0.05% bwoc to 2% bwoc. The superplasticizer may include a polycarboxylate ether, for example, Arkema’s Ethacryl product or BASF’s Liquiment product. The superplasticizer may be added to the cement paste during hydration as a dispersant.

[0128] The example cement composition may further include rheology modifiers, that include, but are not limited to, hydroxyethylcellulose in a concentration range of between approximately 0.05% bwoc and approximately 1.0% bwoc. The replacement level of OPC by the SCMs and functionalized 3DG carbons may be approximately 80%. An example cement composition may include approximately 20% OPC, approximately 80% SCM (metakaolin and limestone) and less than approximately 1 wt% of 3DG carbons functionalized with nano-silica and / or oxygen. OPC may conform to European standards EN 197-1 as CEM I 42.5R or ASTM Type I Portland cement.

[0129] In some implementations, an example cement composition may include ordinary Portland cement (“OPC”), one or more of pyroclastic ash, gypsum, or metakaolin as SCMs and 3DG carbons functionalized with one or more of nano-silica and oxygen. The replacement level of OPC may be at least approximately 70 wt%. The replacement level of OPC may be between approximately 70 wt% and approximately 80 wt%. An example SCM may include approximately 65 wt% metakaolin, approximately 32 wt% limestone, and approximately 3 wt% gypsum. A superplasticizer may be used to improve workability. The amount of 3DG carbons functionalized with one or more of nano-silica or oxygen may be less than approximately 1 wt% of the cement composition. OPC may conform to European standards EN 197-1 as CEM I 42.5R or ASTM Type I Portland cement. During initial hydration (cement slurry formation with water), the water to cement ratio may vary between approximately 0.3 and approximately 0.5.

[0130] 3DG carbons functionalized with nano-silica were analyzed using SEM / EDS for elemental analysis. Figure 6A shows a micrograph 600A of untreated 3DG carbons, and Figures 6B, 6C, and 6D show micrographs 600B, 600C and 600D that confirm the presence of O and Si elements on 3DG carbons that were functionalized by silica.

[0131] Figure 7A shows elemental composition intensity (counts) 700A measured during SEM / EDS analysis of 3DG carbons functionalized with nano-silica, according to some implementations, and Figure 7B shows a box plot 700B of elemental composition distribution measured by SEM / EDS analysis of various 3DG carbons functionalized with nano-silica, according to some implementations. Quantitative analysis of the elemental composition intensity may suggest an interquartile range for Si concentration of between approximately 22 at. wt% and approximately 64 at. wt%, with an average of approximately 44 at. wt%, and that for oxygen concentration of approximately between 18 at. wt% and approximately 38 at. wt%, with an average of approximately 29 at. wt%. The 3DG carbons surface functionalized with nano-silica may include between approximately 20 at. wt% and approximately 65 at. wt% Si, and between approximately 15 at. wt% and approximately 40 at. wt% O.

[0132] The presence of carbon during SEM / EDS analysis suggests that some areas of the 3DG carbons remain in an unfunctionalized state. The O / Si atomic ratio (not shown) had an interquartile range for Si concentration of between approximately 1.6 and approximately 2.8, with an average of approximately 2.5, which suggests that some elemental oxygen does not derive from silica (O / Si ratio of 2), but corresponds to oxygenated 3DG carbons (for example, graphene oxides). The O / Si ratio of 3DG carbons surface functionalized with nano- silica may be between approximately 1.5 and approximately 3.

[0133] Figure 8 shows a thermogram 800 of example cement compositions functionalized with nano-silica, according to some implementations. Samples of example cement compositions with 3DG carbons were subjected to thermogravimetry analysis (TGA). The example thermogram 800 of Figure 8 suggests that between approximately 250oC and 450oC, degradation of the chemical moiety that connects silica to the 3DG carbon surfaces occurs. Silanol groups present on the surface of nano-silica particles and clusters may degrade between approximately 450oC an approximately 700oC and carbon may degrade at between approximately 700oC and approximately 1000oC leaving behind inorganic silica residue.

[0134] In some implementations, an example method for regulating CSH nucleation and time-lapsed growth during the initial hydration of cement may include providing one or moreof the example compositions previously described and mixing and mixing with water, where the water to cement ratio by weight may be vary between approximately about 0.3 and about 0.5. For example, a cement composition may include ordinary Portland cement, a supplementary cementitious material (SCM) including one or more of metakaolin or limestone or gypsum in an amount corresponding to at least approximately 70% replacement level of ordinary Portland cement, and less than approximately 1 wt% of 3DG carbons. The 3DG carbons may include few layer graphene (“FLG”) nanoplatelets orthogonally joined to each other to form a 3D porous graphene scaffold structure, where the 3DG carbons are surface functionalized with one or more of nano-silica or oxygen. An SCM may include approximately 65 wt% metakaolin, approximately 32 wt% limestone, and approximately 3 wt% gypsum.

[0135] In some implementations, 3DG carbons may include aggregates of primary carbon particles that include carbon nano-onions (CNOs) and other allotropes. The primary carbon nanoparticles may include two or more connected multi-walled spherical fullerenes (MWSF). CNOs or multi-walled fullerenes are carbon nanoparticles, generally spherical in shape, and may include multiple concentric shells including graphene that defining a plurality of porous regions or zones nested within each other. The primary carbon nanoparticles may be characterized by a high degree of order (e.g., a Raman signature with an ID / IG ratio from 0.95 to 1.05), and a high purity (e.g., the ratio of carbon to other elements, other than H, is greater than 99.9%). Layers of graphene may coat the connected CNOs in each primary carbon nanoparticle. The one or more shells and carbonaceous regions may include sp2-hybridized carbon (indicative of graphene) and may have minor islands of amorphous sp3-hybridized carbon.

[0136] Synthesis and / or growth of 3DG carbons including CNOs may be produced by thermal cracking of hydrocarbon feedstock as disclosed in one or more of U.S. Pat. No. 9,862,602, U.S. Pat. No. 10,112,837, U.S. Pat. No. 11,053,121, and U.S. Pat. Pub. No. 2021 / 0292170, all of which are incorporated by reference herein in their respective entireties. The 3DG carbons including CNOs may also be surface functionalized as previously described herein.

[0137] Figure 9A shows a diagram of an example primary carbon nanoparticle 900A in 3DG carbons, according to some implementations. The primary carbon nanoparticle 900A includes an inner region 911 surrounded by an outer region 912. The outer region 912 includes an outer boundary 910 of the primary carbon particle 900A. The inner region 911may include a plurality of first pores 901 dispersed therein, and the outer region 912 may include a plurality of second pores 902 dispersed therein. The inner region 911 and outer region 912 may be interconnected by at least some of the first pores 901. The inner region 911 may be associated with a first pore density, and the outer region 912 may be associated with a second pore density that is different than the first pore density. The first pores 901 may be configured to confine dopants 916 to be released as a function of time (time release) during hydration of cement, and the second pores 902 may provide pathways or channels for transport of dopants 916 into and from the primary particle 900A (and for pre-loading dopants into the primary carbon particle 900A. Example primary carbon nanoparticles may be characterized by a size or principal dimension (diameter, length, width) of less than approximately 200 nm. In some instances, polysulfides 920 may be present within the primary carbon particle 900A.

[0138] Figure 9B shows a TEM image 900B of a carbon aggregate 930, according to some implementations. As shown, the carbon aggregate 930 may include a plurality of primary carbon nanoparticles 932 that resemble a “string-of-pearls.” In some implementations, the size or principal dimension of carbon aggregate 930 may be between about 50 nm and 500 nm. Primary carbon nanoparticles 932 may be of any shape, including one or more of spherical, spheroidal, dumbbell, cylindrical, elongated cylindrical type, rectangular prism, disk, wire, or irregular. In some implementations, the primary nanoparticles 932 may be formed of formed of concentric, well-ordered spheres of sp2- hybridized carbon atoms as contrasted with spheres of poorly-ordered, non-uniform, amorphous carbon particles. In the primary nanoparticles 932, pore sizes may gradually decrease along a radial direction from the center of the particle to the outer boundary of the particle. In some example implementations, a multi-shell CNO primary particle may be characterized by a range of pore sizes and pore distributions in each region. The primary nanoparticles 932 and / or carbonaceous layers may also include one or more of few layer graphene (FLG) interconnected platelets, multi-layer graphene (MLG) interconnected platelets, graphite, carbon nano-tubes (CNTs), flat graphene, or wrinkled graphene. The example primary carbon nanoparticles 932 may be characterized as non-hollow carbon spherical particles. In some other implementations, the primary carbon nanoparticles 910 may also include tri-zone particles.

[0139] Figures 9C shows a TEM image of 3-dimensional carbon agglomerates 900C, according to some implementations. The agglomerates 900C may be dispersed in any one ofthe example cement compositions previously described. In some instances, 3DG carbons that form the agglomerates 900C may be functionalized with one or more of oxygen containing functional groups, other functional groups, or atoms, as previously described.

[0140] Figure 10 shows a diagram of another example primary carbon nanoparticle 1000 in 3DG carbons, according to some implementations. The example primary carbon nanoparticle 1000 may include a first zone 1051 nested within a second zone 1052, which in turn is nested within a third zone 1053. The first zone 1051 may include pores having a size or principal dimension (diameter, length width) of less than approximately 40 nm, the second zone 1052 may include pores having a principal dimension of less than approximately 35 nm, and the third zone 1053 may include pores having a principal dimension of less than approximately 30 nm. In some instances, the pores 1061 within the first zone 1051 may be characterized as macropores, the pores 1062 within the second zone may be characterized as mesopores, and the pores 1063 within the third zone 1053 may be characterized as micropores.

[0141] In some aspects, the principal dimension D1 of first zone 1051 may be less than approximately 100 nm, the principal dimension D2 of second zone 1052 may be less than approximately 150 nm, and the principal dimension D3 of third zone 1053 may be approximately 200 nm. The relative dimensions, porosities, and electrical conductivities of the first zone 1051, the second zone 1052, and the third zone 1053 may be tuned by tuning reactor operating conditions to obtain desired particle or aggregate structure, porosity, and particle density. The first zone 1051 may have a density of carbonaceous material of less than approximately 1 g / cc. The third zone 1053 is bounded by an outer shell 1055 and may have a density of carbonaceous material between approximately less than 1 g / cc and 3.5 g / cc. The second zone 1052 may have a density of carbonaceous material between approximately 0.5 g / cc and 3 g / cc. The one or more shells and carbonaceous regions may include sp2- hybridized carbon (indicative of graphene) and may have minor islands of amorphous sp3- hybridized carbon.

[0142] In some implementations, an example cement composition may include between approximately 30 wt% and approximately 35 wt% ordinary Portland cement (“OPC”), approximately 45% by weight of cement (bwoc) metakaolin, approximately 20% bwoc limestone, approximately 5% bwoc gypsum, approximately 0.06% bwoc superplasticizer, and approximately 0.06% bwoc 3DG carbons. The superplasticizer may include a polycarboxylate ether, for example, Arkema’s Ethacryl product or BASF’s Liquimentproduct. The superplasticizer may be added to the cement paste during hydration as a dispersant. In some instances, an example cement composition may include about 70 wt% supplementary cementitious material (“SCM”) including metakaolin, limestone, and gypsum. Accordingly, the replacement level of OPC may be approximately 70%. In some other instances, 3DG carbons may be surface functionalized with one or more of nano-silica or oxygen groups. Examples of oxygen functional groups were previously described herein. The 3DG carbons including surface oxygen groups may nucleate CSH seeds via covalent bonding. In some implementations, the OPC may conform to European standards EN 197-1 as CEM I 42.5R or ASTM Type I Portland cement. Metakaolin may be supplied by Burgess Pigment Company (Sandersville, GA) as Optipozz™ metakaolin. Limestone may be supplied by Omya, Inc. (Cincinnati, OH) as Durcal 15 powders.

[0143] In some implementations, isothermal heat flow calorimetry may be used to examine, monitor, or otherwise analyze the heat released from a hydrating cement paste. The heat released from a hydrating cement may depend on one or more parameters including the fineness of cement and the composition of the cement admixture. The time associated with the appearance of an initial peak representative of the onset of hydration may be used to differentiate between various composition of cement. Additionally, an examination of heat flow may provide insight into the evolution of mechanical strength as the cement sets. Additional details are provided in Examples 7–10 in this disclosure.

[0144] In some implementations, any one of the previously described cement compositions may be formulated as one or more of ready-mix concrete, precast concrete, concrete blocks, concrete paver, concrete pipe, or concrete block, among other examples. Ready-mix concrete may account for approximately 50% to 60% of the global market for concrete products. In some instances, an example concrete composition may include approximately 14 wt% ordinary Portland cement, approximately 31 wt% fine aggregate, approximately 47 wt% coarse aggregate, and approximately 8 wt% water. An example fine aggregate may include sand. Example coarse aggregates may include one or more of gravel or crushed stone. In some implementations, the coarse aggregates may be characterized by an average diameter between approximately 0.375 in. and approximately 1.5 in. In some instances, example fine aggregates may include natural sand or crushed stone. In some implementations, the fine aggregates may be sized to pass through a 3 / 8 in. sieve. In some instances, the average diameter of fine aggregates may be less than approximately 9.5 mm (approximately 0.37 in.).

[0145] In some implementations, the amount of 3DG carbons in an example concrete composition may be approximately 0.1% bwoc. In some other implementations, the amount of 3DG carbons in an example concrete composition may be less than 0.2% bwoc. In some instances, example concrete compositions including 3DG carbons may replace between approximately 20 wt% and approximately 30 wt% of cement with one or more of fine aggregates or coarse aggregates.

[0146] In some implementations, an example concrete composition including 3DG carbons may include between approximately 13 wt% and approximately 14 wt% ordinary Portland cement, approximately 47% coarse aggregates, approximately 31 wt% fine aggregates, approximately 8 wt% water, and approximately 0.06 wt% 3DG carbons (corresponding to 0.15% bwoc). In some other implementations, an example concrete composition including 3DG carbons may include between approximately 9 wt% and approximately 10 wt% ordinary Portland cement, approximately 51 wt% coarse aggregates, approximately 31 wt% fine aggregates, approximately 8 wt% water, and approximately 0.06 wt% 3DG carbons (corresponding to 0.15% bwoc).

[0147] In some implementations, an example concrete composition including 3DG carbons may include between approximately 9 wt% and 10 wt% ordinary Portland cement, approximately 51% coarse aggregates, approximately 31 wt% fine aggregates, approximately 8 wt% water, and approximately 0.02 wt% 3DG carbons (corresponding to 0.05% bwoc). EXAMPLES

[0148] In the examples described below, 3DG carbons were characterized by a surface oxygen concentration of between about 4 at% and 5 at% as measured by X-ray photoelectron spectroscopy (“XPS”). EXAMPLE 1. Compressive strength of mortar samples including cement compositions including the example 3DG carbons

[0149] Mortar samples (or specimens) of Dyckerhoff CEM I 42.5R Portland cement were prepared by mixing cement with water containing about 0.2 wt% (bwoc) BASF Liquiment 5581F superplasticizer, and at a water / cement ratio of about 0.485. To prepare a suspension of 3DG carbons in water, 3DG carbons was added to water in the appropriate quantity and sonicated in a Branson sonicating bath for 10 min. at a quantity sufficient to yield the targeted 3DG content (bwoc) in cement. The target 3DG content in cement compositions included0.1%, 0.2%, 0.25% and 1.0% bwoc. The suspension of 3DG carbons was then added to the mortar samples and mixed.

[0150] The compressive strength of the mortar samples including cement with varying 3DG carbon concentrations was measured using standard test protocol “Standard Test Method for Compressive Strength of Hydraulic Cement Mortars,” ASTM C109. Compressive strength was measured at 1, 3, 7, and 28 days.

[0151] Figure 11 shows a plot 1100 comparing the compressive strength of mortar samples including cement with varying amounts of 3DG carbons, according to some implementations. As can be seen, the addition of 3DG carbons increased the compressive strength of the mortar samples. At 28 days, the compressive strength of the mortar samples increased from about 3250 psi (sample with no 3DG carbons) to about 3625 psi (1% 3DG carbons bwoc), resulting in an increase of about 11.5% in compressive strength. EXAMPLE 2. Early age compressive strength of mortar samples including blended cement compositions including the example 3DG carbons.

[0152] Mortar samples (or specimens) of Dyckerhoff CEM I 42.5R Portland cement blended with metakaolin, limestone, and gypsum were prepared by mixing cement blends with water containing about 0.2 wt% (bwoc) BASF Liquiment 5581F superplasticizer, and at a water / cement ratio of about 0.485. To prepare a suspension of 3DG carbons in water, the 3DG carbons was added to water in the appropriate quantity and sonicated in a Branson sonicating bath for 10 min. at a quantity sufficient to yield the targeted 3DG content (bwoc) in cement. The target 3DG content in cement compositions included 0.05%, 0.1%, and 0.15% bwoc. The suspension of 3DG carbons was then added to the mortar samples and mixed. Mortar samples including the 3DG carbons included about 35% metakaolin, about 20% limestone, and about 3% gypsum (calcium sulfate dihydrate) on a bwoc basis. As such, the replacement level of cement in these test samples was about 55%. In addition, mortar samples using cement blends having no 3DG carbons were also prepared. A first reference sample included about 35% metakaolin, about 20% limestone, and about 3% gypsum on a bwoc basis. As such, the replacement level of cement in the first reference sample was about 55%. A second reference sample included about 30% metakaolin, 15% limestone and 3% gypsum on a bwoc basis. As such, the replacement level of cement in the second reference sample was about 45%.

[0153] The compressive strength of the mortar samples including cement with varying 3DG carbon contents was measured using standard test protocol “Standard Test Method forCompressive Strength of Hydraulic Cement Mortars,” ASTM C109. Compressive strength was measured at 1, 3, and 7 days. As a reference, the minimum compressive strength requirement according to “Standard Performance Specification for Hydraulic Cement,” ASTM C1157, for early age compressive strength of hydraulic cements for general construction at curing durations of 3 days and 7 days is approximately 2000 psi and approximately 3000 psi, respectively.

[0154] Figure 12 shows a plot 1200 comparing the early age compressive strength of mortar samples including cement with varying amounts of 3DG carbons, according to some implementations. As can be seen, the addition of between approximately 0.05% and 0.15% bwoc 3DG carbons increased the compressive strength of the mortar samples with a cement replacement level of about 55%. As such, 3DG carbons accelerates the setting of Portland cement. Additionally, the compressive strength of the example mortar compositions including 3DG carbons is greater than the minimum compressive strength requirements even at a cement replacement level of about 55%. As described below with reference to Example 3, mortar including 3DG carbons was characterized by reduced water absorption and chloride permeability, and accordingly, enhancement in durability, relative to mortar not including 3DG carbons.

[0155] Without being bound by any particular theory, the enhanced mechanical properties mortar including 3DG carbons may be attributed to one or more of reinforcing effect of graphene nanosheets in 3DG carbons or nucleation effect of graphene oxide with regards to the pozzolanic activity of supplementary cementitious materials (SCMs) including metakaolin. Graphene in 3DG carbons may nucleate, seed, and accelerate C-S-H growth through the pozzolanic reaction of the silicates in metakaolin with calcium hydroxide in the cement. Regulated gelation and formation of ‘entangled’ fiber macromolecules from dispersed 3DG carbon fillers may produce a high-strength geopolymer binder matrix. A geopolymer is generally an aluminosilicate inorganic polymer characterized by a covalently bonded, amorphous, or semi-crystalline matrix or network. EXAMPLE 3. Water absorption rates in mortar samples including blended cement compositions including the example 3DG carbons.

[0156] Mortar samples (or specimens) of Dyckerhoff CEM I 42.5R Portland cement blended with metakaolin, limestone, and gypsum were prepared by mixing cement blends with water containing about 0.2 wt% (bwoc) BASF Liquiment 5581F superplasticizer, and at a water / cement ratio of about 0.485. To prepare a suspension of 3DG carbons in water, the3DG carbons was added to water in the appropriate quantity and sonicated in a Branson sonicating bath for 10 min. at a quantity sufficient to yield the targeted 3DG content (bwoc) in cement. The target 3DG content in cement compositions was about 0.3% bwoc. The suspension of 3DG carbons was then added to the mortar samples and mixed. The composition of mortar samples prepared for testing is summarized in Table 2 below:Table 2. Composition of mortar samples bwoc prepared for water absorption tests

[0157] As such, the replacement level of cement in test samples R60-0 and R60-3 was about 60%. Water absorption rates of the mortar samples including cement with varying 3DG carbon contents were measured using standard test protocol “Standard Test Method for Measurement of Rate of Absorption of Water by Hydraulic-Cement Concretes,” ASTM C1585. For testing purposes, samples with compositions as shown in Table 1 were prepared as 4 in. (diameter) x 8 in. (length) cylinders and cured in limewater at about 23oC for 28 days. The cured samples were then cut into discs of about 2 inches thick.

[0158] Figure 13 shows a plot 1300 comparing the water absorption rate of mortar samples including cement with varying amounts of 3DG carbons, according to some implementations. As can be seen, the water absorption rate (initial sorptivity over the first 6 hours) of the reference sample and the sample without any 3DG carbons were found to be similar. However, with the addition of 0.3% 3DG carbons, the water absorption rate at x-axis values (square root of time in seconds) greater than about 80 (s1 / 2) of the R60-3 sample decreased by more than 100% to less than 1 mm at a square root time greater than 80 s1 / 2. EXAMPLE 4. Rate of chloride ion penetration tests (“RCPT”) in mortar samples including blended cement compositions including the example 3DG carbons

[0159] Mortar samples as described in Example 3 were subjected to RCPT tests using standard test protocol “Standard Test Method for Electrical Indication of Concrete’s Ability to Resist Chloride Ion Penetration,” ASTM C1202.

[0160] Figure 14 shows a plot 1400 comparing the charge passed through mortar samples during RCPT including cements with varying amounts of 3DG carbons, according to some implementations. As can be seen, the reference sample R0-0 showed the highest charge passed through value of about 7800 coulombs, which is indicative of high chloride ion penetration across the sample. Sample R60-0 showed a moderate charged passed through value of about 660 coulombs. In contrast, sample R60-3 including about 0.3% 3DG carbons, and with a 60% cement replacement showed the lowest charge passed through value of about 175 coulombs. These results demonstrate that cement compositions or mortars including 3DG carbons may significantly improve resistance to chloride penetration. EXAMPLE 5. Rapid chloride migration test (“RCM”) in mortar samples including blended cement compositions including the example 3DG carbons

[0161] Mortar samples as described in Example 3 were subjected to RCM tests using test protocol NT Build 492. During testing under NT Build 492, the samples were saturated in limewater. The NT Build 492 test protocol may be viewed as an alternative to ASTM C1202 and is generally used to examine non-steady state chlorine migration in mortar or concrete samples.

[0162] Figure 15 shows a plot 1500 comparing the non-steady state chloride migration coefficient during RCM tests through mortar samples including cements with varying amounts of 3DG carbons, according to some implementations. As can be seen, the non- steady state migration coefficient (“D”) for mortar sample R60-3 including 3DG carbons was less than 5 x 1012m2 / s, which corresponds to about 10x reduction in chloride permeability relative the chloride permeability associated with Portland cement (R0-0 sample). Additionally, the chloride permeability associated with the mortar sample R60-3 including 3DG carbons was about 3x lower than the chloride permeability associated with the mortar sample R60-0 that did not include 3DG carbons. The coefficient D may be considered to be an indicator of non-steady state chloride permeability and may be calculated using the equation shown in Figure 15. Additionally, mortar including 3DG carbons may also be characterized by reduced water absorption relative to pure Portland cement or mortar that does not include 3DG carbons. EXAMPLE 6. Early age compressive strength of mortar samples including the example 3DG carbons.

[0163] Mortar samples (or specimens) of ordinary Portland cement blended with metakaolin and limestone at 70% replacement levels were prepared by mixing the cement blends with water containing 3DG carbons. The 3DG content in the example samples included approximately 0.1% bwoc and approximately 0.15% bwoc. In addition, a reference sample including mortar using cement blends (70% replacement level) having no 3DG carbons was also formulated. The compressive strength of the mortar samples including cement with varying 3DG carbon contents was measured using standard test protocol “Standard Test Method for Compressive Strength of Hydraulic Cement Mortars,” ASTM C109. Compressive strength was measured at 1, 3, and 7 days.

[0164] Figure 16 shows a plot 1600 comparing the compressive strength of mortar samples including cement with varying amounts of 3DG carbons, according to some implementations. As can be seen, the compressive strength of the example mortar compositions including 3DG carbons was greater than the minimum compressive strength requirements under ASTM C1157 even at a cement replacement level of about 70%. As previously described herein, the minimum compressive strength requirement according to “Standard Performance Specification for Hydraulic Cement,” ASTM C1157, for early age compressive strength of hydraulic cements for general construction at curing durations of 3 days and 7 days is approximately 2000 psi and approximately 3000 psi, respectively. EXAMPLE 7. Isothermal heat flow calorimetry of hydrating cements including the example 3DG carbons.

[0165] Mortar samples of ordinary Portland cement blended with metakaolin and limestone as supplementary cementitious materials at 45% replacement levels were prepared by mixing the cement blends with water containing 3DG carbons. The 3DG content in the mortar samples included approximately 0.2% bwoc, and approximately 1.0% bwoc. In addition, a reference sample including mortar using cement blends (45% replacement level) having no 3DG carbons was also prepared.

[0166] Figure 17 shows a plot 1700 comparing heat flow calorimetric patterns associated with early age hydrating cement samples with varying amounts of 3DG carbons, according to some implementations. As can be seen from the onset of the hydration peaks 1701, the addition of 3DG carbons accelerates cement setting even at 45% cement replacement levels. Without being bound by any particular theory, the hydration peaks may be associated with the hydration of tricalcium silicate (“C3S”) in cement. Additionally, the heat flow (W / g) associated with the hydration peaks suggest that thermal power decreases with increasingamount of 3DG carbons in the cement samples, with heat flow decreasing from approximately 0.008 W / g for cement samples with no 3DG carbons to approximately 0.004 W / g for cement samples with approximately 1% bwoc 3DG carbons. EXAMPLE 8. Isothermal heat flow calorimetry of hydrating cements including 3DG carbons and ozone oxidized 3DG carbons.

[0167] Mortar samples (or specimens) of ordinary Portland cement were prepared by mixing cement with water including approximately 0.2% bwoc superplasticizer (Euclid Plastol 341) and 3DG carbons. The 3DG carbon content in cement samples was between approximately 0.1% bwoc and approximately 2% bwoc. A reference sample including mortar having no 3DG carbons was also prepared.

[0168] Additionally, mortar samples (or specimens) of ordinary Portland cement were prepared by mixing the cement blends with water containing approximately 0.2% bwoc superplasticizer (Euclid Plastol 341) and ozone oxidized 3DG carbons (“O3–3DG carbons”). The O3–3DG carbons content in cement samples was between approximately 0.1% bwoc and approximately 0.2% bwoc.

[0169] Figure 18A shows a plot 1800A comparing heat flow calorimetric patterns associated with hydrating cement samples with varying amounts of 3DG carbons and ozone oxidized 3DG carbons, according to some implementations. Figure 18B shows a plot 1800B comparing cumulative heat release over time associated with hydrating cement samples with varying amounts of 3DG carbons and ozone oxidized 3DG carbons, according to some implementations. As can be seen from plot 1800A, the heat flow (W / g) curves associated with samples including 3DG carbons (not ozone oxidized) show vertical stacking of the curves with the reference cement sample (no 3DG carbons) showing the lowest generated thermal power from cement hydration. Heat flow increases with increasing amounts of 3DG carbons in the cement samples.

[0170] Additionally, the heat flow patterns in plot 1800A suggest that the cement samples including O3–3DG carbons are characterized by higher heat flows (relative to that of non- oxidized 3DG carbons) even at low amounts of O3–3DG carbons of less than approximately 0.2% bwoc. Without being bound by any particular theory, ozone oxidation may produce oxygen-containing functional groups in and / or on the surfaces of 3DG carbons, which may increase the exothermicity associated with the hydration reactions and increase the mechanical strength of cement.

[0171] Turning to plot 1800B, the cumulative thermal patterns also show vertical stacking of the curves with the reference cement sample (no 3DG carbons) showing the lowest cumulative thermal power from cement hydration. Additionally, the cumulative flow patterns in plot 1800B suggest that the cement samples including O3–3DG carbons are characterized by higher heat flows (relative to that of non-oxidized 3DG carbons with the exception of samples including 2% bwoc) even at low amounts of O3– 3DG carbons of less than approximately 0.2% bwoc. EXAMPLE 9. Isothermal heat flow calorimetry of hydrating cements including ozone oxidized 3DG carbons.

[0172] To further examine the beneficial effect of ozone oxidized 3DG carbons in cement, mortar samples (or specimens) of Portland cement were prepared by mixing the cement blends with water containing approximately 0.2% bwoc superplasticizer (Euclid Plastol 341). The ozone oxidized 3DG carbon content in cement samples was between approximately 0.1% bwoc and approximately 2% bwoc. A reference sample including mortar using cement blends having no 3DG carbons was also prepared.

[0173] Figure 19A shows a plot 1900A comparing heat flow calorimetric patterns associated with hydrating cement samples with varying amounts of ozone oxidized 3DG carbons, according to some implementations. Figure 19B shows a plot 1900B comparing cumulative heat release over time associated with hydrating cement samples with varying amounts of ozone oxidized 3DG carbons, according to some implementations. As can be seen from plot 1900A, the heat flow patterns suggest that the cement samples including ozone oxidized 3DG carbons (“O3”) are characterized by higher heat flows (relative to that of non-oxidized 3DG carbons) with heat flow increasing with increasing amounts of ozone oxidized 3DG carbons.

[0174] Turning to plot 1900B, the cumulative thermal patterns also suggest vertical stacking of the curves with the reference cement sample (no 3DG carbons) showing the lowest cumulative thermal power from cement hydration. Additionally, the cumulative thermal power appears to increase with increasing amounts of ozone oxidized 3DG carbons in cement. EXAMPLE 10. Isothermal heat flow calorimetry of hydrating cements including 3DG carbons surface functionalized with nano-silica.

[0175] To examine the beneficial effect of cement including 3DG carbons surface functionalized with nano-silica, mortar samples of Portland cement were prepared by mixing the cement blends with water containing 3DG carbons surface functionalized with nano- silica. A reference sample including mortar using cement blends having no 3DG carbons was also prepared.

[0176] Figure 20A shows a plot 2000A comparing heat flow calorimetric patterns associated with hydrating cement samples including 3DG carbons surface functionalized with nano-silica, according to some implementations. Figure 20B shows a plot 2000B comparing cumulative heat release over time associated with hydrating cement samples including 3DG carbons surface functionalized with nano-silica, according to some implementations. Nano- silica may be disposed as a “string of pearls” on the surface of 3DG carbons as shown in Figure 5A. Nano-silica may also be disposed as rods or tubes as shown in Figure 5B.

[0177] As can be seen from plot 2000A, the heat flow patterns suggest that the cement samples including 3DG carbons surface functionalized with nano-silica are characterized by higher heat flows (relative to that of the reference cement composition) as the average size of nano-silica particles decreased from approximately 50 nm to approximately 5 nm. with heat flow increasing with decreasing particle diameter. Without being bound by any particular theory, decreasing the nano-silica particle size on the surface of 3DG carbons may increase the exothermicity associated with the hydration reactions and increase the mechanical strength of cement.

[0178] Turning to plot 2000B, the cumulative thermal patterns also suggest vertical stacking of the curves, with the reference cement sample containing no 3DG carbons showing the lowest cumulative thermal power from cement hydration. Additionally, the cumulative thermal power appears to increase with decreasing size of the nano-silica particles. As previously described herein, nano-silica particles may function as distributed catalytic sites, and as such, as seeding agents for CSH during hydration and subsequent growth of CSH polymeric chains in the cement matrix. The hydration process may be accelerated due to improved dissolution of C3S in water and acceleration of the pozzolanic activity of the SCMs to convert CH to CSH. Further 3DG carbons functionalized with nano-silica may anchor CSH polymeric chains and may provide structural reinforcement during hydration and setting. EXAMPLE 11. Compressive strength of concrete including the example 3DG carbons.

[0179] Concrete samples were prepared including 3DG carbons at approximately 0.15% bwoc and EthacrylTM(Arkema) as a superplasticizer (“Sample A”). The concrete samples were subjected to compressive strength testing using standard test protocol “Standard Test Method for Compressive Strength of Cylindrical Concrete Specimens,” ASTM C39.

[0180] Figure 21 shows a plot 2100 comparing the compressive strength of concrete including 3DG carbons with that of reference concrete as a function of time, according to some implementations. The amount of 3DG carbons in the concrete formulation was approximately 0.02 wt% (approximately 0.15% bwoc). The composition of the reference concrete samples was approximately 14 wt% cement, approximately 31 wt% fine aggregate, approximately 47 wt% coarse aggregate, and approximately 8 wt% water. The compressive strength of concrete including 3DG carbons was approximately 2250 psi at 1 day-curing, which corresponds to approximately 55% increase in compressive strength compared to that of the reference concrete samples. The compressive strength of concrete including 3DG carbons was approximately 4000 psi at 3 days-curing, which corresponds to approximately 48% increase in compressive strength compared to that of the reference concrete samples. The compressive strength of concrete including 3DG carbons at 7 days was between approximately 4500 psi and approximately 5000 psi, which corresponds to an approximately 37%increase in compressive strength compared to that of the reference concrete samples.

[0181] Accordingly, concrete including low concentrations of 3DG carbons (approximately 0.02 wt% or 0.15% bwoc) may be characterized by an increase in compressive strength of at least 25% compared to the compressive strength of reference concrete samples without 3DG carbons. Concrete compositions including 3DG carbons may enable the replacement of Portland cement using supplementary cementitious materials (SCMs) and increased quantities of aggregates in the formulation and may significantly reduce the production cost of concrete. Concrete including 3DG carbons may also reduce carbon footprint associated with the production of concrete and may increase the lifespan of concrete in various applications.

[0182] As previously described with reference to mortar samples including 3DG carbons (see Example 5), concrete including 3DG carbons may also be characterized by reduced water absorption and chloride permeability relative to pure Portland cement or mortar that does not include 3DG carbons.

[0183] Without being bound by any particular theory, the composition of concrete including 3DG carbons may be tuned to further increase mechanical properties, for example,increasing compressive strength to meet the requirements of high-performance concrete (“HPC”). In general, high-performance concrete may refer to concrete with a 28-day compressive strength of at least 70 MPa (about 10,200 psi). Concrete formulated with 3DG carbons may increase the lifespan of concrete roads and bridges. Concrete formulated with 3DG carbons may also substantially reduce the need for remedial repair of transportation structures. EXAMPLE 12. Compressive strength of concrete including the example 3DG carbons.

[0184] Concrete samples were prepared including 3DG carbons at approximately 0.1% bwoc and EthacrylTM(Arkema) as a superplasticizer (“Sample B”). The concrete samples were subjected to compressive strength testing using standard test protocol “Standard Test Method for Compressive Strength of Cylindrical Concrete Specimens,” ASTM C39.

[0185] Figure 22 shows a plot 2200 comparing the compressive strength of concrete including 3DG carbons with that of reference concrete as a function of time, according to some implementations. The composition of concrete samples Sample A and the composition of the reference concrete samples were previously described under Example 11. As can be seen, the compressive strength of concrete including 3DG carbons at approximately 0.1% bwoc (Sample B) at both 1-day and 3-day periods was higher than that of the reference concrete sample. The compressive strength of concrete Sample B at a period of 3 days was between approximately 3000 psi and approximately 3250 psi, which corresponds to an approximately 30% increase in compressive strength compared to that of the reference concrete samples. EXAMPLE 13. Effect of additives on the properties of concrete including the example 3DG carbons.

[0186] Concrete samples, Sample C (approximately 0.15% bwoc 3DG carbons) and Sample D (approximately 0.1% bwoc 3DG carbons) were formulated using BASF’s Liquiment®product as the superplasticizer. In all other aspects, the composition of Sample C was similar to that of Sample A (concrete including approximately 0.15% bwoc 3DG carbons) and the composition of Sample D was similar to that of Sample B (concrete including approximately 0.1% bwoc 3DG carbons) as previously described with respect to Examples 11 and 12. The concrete samples were subjected to compressive strength testing using standard test protocol “Standard Test Method for Compressive Strength of Cylindrical Concrete Specimens,” ASTM C39.

[0187] Figure 23 shows a plot 2300 comparing the increase in compressive strength of concrete including 3DG carbons relative to the compressive strength of a reference concrete as a function of time, according to some implementations. The composition of the reference concrete was previously described under Example 11. As can be seen, the increase in compressive strength corresponding to each of the samples A–D relative to the compressive strength of the reference concrete sample suggests that the compressive strength of concrete may also be tuned by the choice of superplasticizer material. EXAMPLE 14. Characterization of 3DG carbons.

[0188] 3DG carbon samples produced by processing a hydrocarbon gas in a microwave reactor, as previously described herein, were examined using Raman spectroscopy, X-ray diffraction (XRD), BET surface area analysis, X-ray fluorescence (XRF), and instrumental gas analysis (IGA–O). Table 3 summarizes the analytical results of four 3DG carbons, namely, Si65, Si67, Si68, Si69, before and after ozone oxidation. Additionally, properties associated with an ozone treated sample “O3-OEXT214,” and an untreated 3DG carbons sample Si61 are also shown in Table 3. In Table 3, ozone oxidized 3DG carbons samples are identified by the pre-fix (“O3”). Table 3. Properties of 3DG carbons before and after ozone oxidation.

[0189] As can be seen, the 2D / G intensity ratio of the 3DG carbons samples (associated with the Raman spectra of 3DG carbons) was less than 1, which suggests that the grapheneflakes in the 3DG carbons includes multiple graphene layers. The number of graphene layers estimated using XRD analysis was between 9 and 13. The D / G intensity ratio of the 3DG carbon samples was less than 1, which suggests that the graphene flakes have a low defect density. The increase in the D / G intensity ratio of the ozone treated 3DG carbons relative to the respective untreated 3D carbons samples supports the presence of surface functional groups.

[0190] The BET surface area of the 3DG carbon samples was between about 100 m2 / g and about 400 m2 / g. The approximate oxygen content associated with oxygen containing functional groups and measured using instrumental gas analysis (IGA–O) of the ozone treated 3DG carbons samples was between about 3 wt% and about 7 wt%. EXAMPLE 15. Surface functionalization of 3DG carbons with nano-silica surface functional groups.

[0191] 3DG carbons samples were treated with tetraethyl orthosilicate (TEOS) to generate surface nano-silica functional groups. In some cases, 3DG carbon samples were ozone oxidized to generate oxygen functional groups prior to treatment with TEOS. The 3DG carbons samples were added to water at a concentration of about 10 g / L, homogenized with a high-sheer mixer for about 5 min. at about 12000 rpm, and sonicated using an ultrasound sonicator using 10 second pulses for about 20 min. The pH of the admixture was adjusted to 9–10 pH by adding, for example, ammonium hydroxide. No surfactant was used during preparation of liquid admixtures including ozone oxidized 3DG carbons. The suspension was then centrifuged for about 45 min. under up to 25,300G force. The supernatant was collected and analyzed for particle size using dynamic light scattering (DLS), and for nano-silica functionalized 3DG carbon yield using UV-Vis spectroscopy.

[0192] A surfactant was used during preparation of liquid admixtures including 3DG carbons samples that were not subjected to ozone oxidation. The surfactant was added after high-shear mixing and prior to ultrasonication. Example surfactants included Ethacryl G or sodium dodecylbenzenesulfonate (SDBS). After centrifugation, the supernatant liquid admixture including 3DG carbons was filtered and collected. Optionally, the supernatant liquid admixture including 3DG carbons may be resuspended in low volumes of water to increase nano-silica functionalized 3DG carbons yield, to improve the stability of the 3DG carbons in the liquid admixture. Stability may be monitored by monitoring the particle size of the 3DG carbons in the liquid admixture as a function of time. Well dispersed 3DGcarbons (that is, negligible clumping of 3DG carbons) are deemed to be stable with no significant change in particle size as a function of time.

[0193] Table 4 summarizes particle size analysis of 3DG carbons including nano-silica surface functional groups, in the supernatant liquid admixture and in the sediment or pellet after centrifugation, as described above. 0.1% SDBS was used as the surfactant. As can be seen, after centrifugation for about 45 min., 3DG carbons were separated into the supernatant liquid. The average particle size of the 3DG carbons in the supernatant liquid admixture was about 100 nm.

[0194] In Table 4, ozone oxidized 3DG carbons including nano-silica functionalization samples are identified with an “O3-” suffix. In liquid admixture formulations including 3DG carbons including oxygen functional groups, no surfactant was used. After centrifugation for about 45 min., 3DG carbons were separated into the supernatant liquid. The average particle size of the 3DG carbons in the supernatant liquid admixture was about 100 nm.Table 4. Particle size analysis of 3DG carbons in the supernatant liquid admixture and in the sediment or pellet after centrifugation at different centrifugation times.

[0195] Table 5 shows particle size and supernatant liquid admixture yields for 3DG carbons and ozone oxidized 3DG carbons produced using the methods previously described under Example 15. In both cases, the 3DG carbons include nano-silica surface functionalgroups. SDBS was used as the surfactant during preparation of the liquid admixture including 3DG carbons (not ozone oxidized). The concentration of SDBS in the liquid was about 0.2%.Table 5. Supernatant liquid admixture yields.

[0196] As can be seen the particle size of the 3DG carbons in both cases was between about 90 nm and about 120 nm. The yield of the supernatant liquid admixture measured after centrifugation was between about 40% and about 45% in the presence of the SDBS surfactant. The yield of the supernatant liquid admixture including ozone oxidized 3DG carbons (SDBS surfactant was not used) measured after centrifugation was between about 20% and about 30%. The yield is measured from the ratio of the optical density of visible light (550 nm wavelength) of the suspension before centrifugation and of the supernatant after centrifugation. In some instances, the samples may be diluted by about 500x to get the visible optical density with a standard UV / Vis spectrometer. EXAMPLE 16. Stability of ozone oxidized 3DG carbons with nano-silica surface functional groups.

[0197] Liquid admixtures of ozone oxidized 3DG carbons including nano-silica functional groups were prepared, as described above under Example 15 for stability tests over 30 days. Stability may be monitored by monitoring the particle size of the 3DG carbons in the liquid admixture as a function of time. Well dispersed 3DG carbons (that is, negligible clumping of 3DG carbons) are deemed to be stable with no significant change in particle size as a function of time.

[0198] Table 6 summarizes particle size analysis of 3DG carbons in the supernatant liquid admixture over a period of 7 days. The 3DG carbons sample with the “O3-2x” prefix was prepared by filtering the 3DG carbons from the liquid admixture and resuspending the 3DG carbons in water. In both cases, the centrifugation time associated with preparing the liquid admixture was about 45 min.

[0199] As can be seen, the particle size of the ozone oxidized 3DG carbons was stable at between about 90 nm and about 100 nm after 7 days even in the absence of a surfactant. Theconcentration of 3DG carbons in the liquid mixture was about 2 g / liter. Additionally, the particle size of the resuspended 3DG carbons was stable at about 120 nm after 7 days even in the absence of a surfactant. The concentration of 3DG carbons in the liquid mixture was between about 3 g / liter and about 5 g / liter.Table 6. Stability of 3DG carbons in liquid admixture.

[0200] Figure 24 shows a plot 2400 comparing particle size distribution of 3DG carbons in a liquid admixture as a function of time, according to some implementations. The 3DG carbons samples included surface nano-silica functional groups, but were not ozone oxidized prior to nano-silica functionalization. As such, the liquid admixture included SDBS as a surfactant. The particle size distribution of 3DG carbons samples associated with liquid admixtures after storing for 0 days (that is, as prepared), 20 days, and 30 days was measured. As can be seen, the particle size of 3DG carbons was stable at between about 90 nm and about 110 nm over the 30-day period. EXAMPLE 17. Morphology of nano-silica surface functionalized 3DG carbons.

[0201] Figure 25A shows a scanning transmission electron microscopy (“STEM”) micrograph 2500A of 3DG carbons, according to some implementations. Figure 25B shows an electron energy loss spectroscopy (“TEM-EELS”) micrograph 2500B of 3DG carbons, according to some implementations. As shown in micrograph 2500A, 3DG carbons may include one or more graphene flakes 2501 that may include few layers of graphene or multiple layers of graphene. Additionally, graphene flakes 2501 may be characterized by a wavy or wrinkled morphology. Graphene flakes 2501 may include carbon regions 2502, which are represented as bright areas in micrograph 2500A, and as red regions in micrograph 2500B. As can be seen in micrograph 2500B, TEM-EELS analysis confirmed the presence of silicon as silica functional groups or particles (“SiOx”) 2503 disposed on the surfaces of 3DG carbon, where the SiOx particles 2503 are shown as green areas. The average size ofnano-silica particles 2503 may be between about 5 nm and about 10 nm. Additionally, as can be seen in micrograph 2500B, TEM-EELS analysis also confirmed the presence of oxygen containing surface functional groups 2504 disposed on carbon surfaces, where the functional groups including oxygen bound to carbon surfaces are shown as blue dots.

[0202] As used herein, a phrase referring to “at least one of” or “one or more of” a list of items refers to any combination of those items, including single members. For example, “at least one of: a, b, or c” is intended to cover the possibilities of: a only, b only, c only, a combination of a and b, a combination of a and c, a combination of b and c, and a combination of a and b and c. Unless otherwise specified in this disclosure, for construing the scope of the term “about” or “approximately,” the error bounds associated with the values (dimensions, operating conditions etc.) disclosed is ± 10% of the values indicated in this disclosure. As used herein, a “cement composition” also includes a “hydrating cement composition.” Accordingly, the example 3DG carbons disclosed herein, including the surface functionalized 3DG carbons, may be dispersed in water and added to a cement composition or mortar composition during the hydration process. The error bounds associated with the values disclosed as percentages is ± 1% of the percentages indicated. The word “substantially” used before a specific word includes the meanings “considerable in extent to that which is specified,” and “largely but not wholly that which is specified.”

[0203] Various modifications to the implementations described in this disclosure may be readily apparent to persons having ordinary skill in the art, and the generic principles defined herein may be applied to other implementations without departing from the spirit or scope of this disclosure. Thus, the claims are not intended to be limited to the implementations shown herein but are to be accorded the widest scope consistent with this disclosure, the principles and the novel features disclosed herein.

[0204] Additionally, various features that are described in this specification in the context of separate implementations also can be implemented in combination in a single implementation. Conversely, various features that are described in the context of a single implementation also can be implemented in multiple implementations separately or in any suitable subcombination. As such, although features may be described above in combination with one another, and even initially claimed as such, one or more features from a claimed combination can in some cases be excised from the combination, and the claimed combination may be directed to a subcombination or variation of a subcombination.

[0205] Similarly, while operations are depicted in the drawings in a particular order, this should not be understood as requiring that such operations be performed in the particular order shown or in sequential order, or that all illustrated operations be performed, to achieve desirable results. Further, the drawings may schematically depict one more example processes in the form of a flowchart or flow diagram. However, other operations that are not depicted can be incorporated in the example processes that are schematically illustrated. For example, one or more additional operations can be performed before, after, simultaneously, or between any of the illustrated operations. In some circumstances, multitasking and parallel processing may be advantageous. Moreover, the separation of various system components in the implementations described above should not be understood as requiring such separation in all implementations, and it should be understood that the described program components and systems can generally be integrated together in a single product or packaged into multiple products.

Claims

CLAIMS What is claimed is:

1. A cement composition including: ordinary Portland cement; a supplementary cementitious material (SCM) including one or more of metakaolin, limestone, or gypsum in an amount between approximately 45% and approximately 70% of a replacement level of ordinary Portland cement; a superplasticizer in a concentration range of between approximately 0.05% by weight of cement (bwoc) and 2% bwoc; and a carbon-based material including three-dimensional graphene flakes (3DG carbons) in amounts of between approximately 0.05% bwoc and 2% bwoc, wherein the 3DG carbons include one or more of oxygen containing functional groups or nano-silica particles disposed on one or more of the surfaces of the 3DG carbons or within the 3DG carbons.

2. The cement composition of claim 1, wherein an early age compressive strength of the cement composition measured using ASTM C109 at a hydration period of 3 days is greater than the corresponding minimum compressive strength requirement for hydraulic cements as specified by ASTM C1157.

3. The cement composition of claim 1, wherein the 3DG carbons including oxygen containing functional groups are dispersed in water and added to the cement composition during hydration.

4. The cement composition of claim 1, wherein the 3DG carbons include one or more interconnected bundles of electrically conductive graphene layers.

5. The cement composition of claim 4, wherein the graphene layers are arranged as one or more stacks connected to each other to define a 3D porous scaffold structure including mesopores.

6. The cement composition of claim 5, wherein the one or more stacks are disposed substantially orthogonal to each other.

7. The cement composition of claim 4, wherein the graphene layers are characterized by a linear dimension of between approximately 50 nm and 200 nm.

8. The cement composition of claim 7, wherein the graphene layers include one or more of single layer graphene (SLG), few layer graphene (FLG), or many layer graphene (MLG).

9. The cement composition of claim 1, wherein the 3DG carbons are characterized by a Raman spectroscopy signature having an ID / IG ratio of less than 1.

10. The cement composition of claim 1, wherein the 3DG carbons are characterized by a Brunauer–Emmett–Teller (BET) surface area between approximately 50 m2 / g and 300 m2 / g measured using nitrogen gas.

11. The cement composition of claim 1, wherein the 3DG carbons are characterized by a graphene to amorphous carbon ratio of between approximately 1% and 95%.

12. The cement composition of claim 1, wherein the 3DG carbons are characterized by an electrical conductivity of between approximately 500 S / m and 20,000 S / m when compressed at pressure of approximately 12,000 pounds per square inch (psi).

13. The cement composition of claim 1, wherein the oxygen containing functional groups includes one or more of epoxide (C–O–C), hydroxyl (–OH), ether (C–O–C), ketone (O–C=O), or carboxylic acid (–COOH) groups.

14. The cement composition of claim 1, wherein an oxygen concentration associated with the oxygen containing functional groups is between approximately 1 wt% and 25 wt%.

15. The cement composition of claim 1, wherein an oxygen concentration associated with the oxygen containing functional groups disposed on the surface of the 3DG carbons is between approximately 4 at% and 5 at%.

16. The cement composition of claim 1, wherein the SCM includes between about 20 wt% and about 35 wt% metakaolin bwoc, between approximately 15% and 40 wt% limestone bwoc, and between approximately 0.5 wt% and 3.5 wt% gypsum bwoc.

17. The cement composition of claim 1, wherein the superplasticizer includes one or more of polycarboxylate ether, sulfonated naphthalene formaldehyde condensate, sulfonated melamine formaldehyde condensate, or acetone formaldehyde condensate.

18. The cement composition of claim 1, wherein the 3DG carbons are dispersed in water and added to the cement composition during hydration.

19. A mortar composition including: the cement composition of claim 1; and sand.

20. A concrete composition including: the cement composition of claim 1; and one or more of fine aggregates or coarse aggregates, wherein a compressive strength measured using ASTM C39 at a hydration period of 28 days is at least about 1 MPa.

21. The concrete composition of claim 1, wherein the compressive strength is between about 1 MPa and about 55 MPa.

22. The concrete composition of claim 1, wherein the compressive strength is between about 30 MPa and about 100 MPa.

23. The concrete composition of claim 1, wherein the compressive strength is between about 40 MPa and about 130 MPa.

24. The concrete composition of claim 1, wherein the compressive strength is between about 100 MPa and about 150 MPa.

25. The concrete composition of claim 1, wherein the compressive strength is greater than 150 MPa.

26. A method of making a mortar including a cement composition, the method including: forming a first mixture by mixing a cement blend with water at a water to cement ratio by weight of between approximately 0.3 and 0.5, wherein the cement blend includes: ordinary Portland cement; a supplementary cementitious material (SCM) including one or more of metakaolin, limestone, or gypsum in an amount between approximately 45% and approximately 70% of a replacement level of ordinary Portland cement; and a superplasticizer in a concentration range of between approximately 0.05% by weight of cement (bwoc) and 2% bwoc; and mixing a suspension of carbon-based material including three-dimensional graphene flakes (3DG carbons) in water into the first mixture, wherein the 3DG carbons include one or more of oxygen containing functional groups or nano-silica particles disposed on one or more of the surfaces of the 3DG carbons or within the 3DG carbons.

27. The method of claim 26, wherein an amount of 3DG carbons in the mortar is between approximately 0.05% bwoc and 2% bwoc.

28. The method of claim 26, wherein the SCM includes between approximately 20 wt% and 35 wt% metakaolin bwoc, between approximately 15% and 40 wt% limestone bwoc, and between approximately 0.5 wt% and 3.5 wt% gypsum bwoc.

29. The method of claim 28, wherein a water absorption rate of the mortar measured using ASTM C1585 is less than 1 mm at a square root time greater than 80 s1 / 2.

30. The method of claim 28, wherein a charge passed through value of the mortar measured using ASTM C1202 is less than 200 coulombs after a curing period of 28 days.

31. The method of claim 28, wherein a non-steady state chloride migration coefficient of the mortar based on NT Build 492 tests is less than 5 x 1012m2 / s after a curing period of 28 days.

32. A concrete composition including: a base composition including: between approximately 9 wt% and approximately 15 wt% ordinary Portland cement; between approximately 45 wt% and approximately 50 wt% coarse aggregates; between approximately 30 wt% and approximately 35 wt% fine aggregates; and between approximately 5 wt% and approximately 10 wt% water; and a carbon-based material including three-dimensional graphene flakes (3DG carbons) in amounts of between approximately 0.05% bwoc and 0.5% bwoc, wherein the 3DG carbons include one or more of nano-silica particles or oxygen containing functional groups disposed on one or more of the surfaces of the 3DG carbons or within the 3DG carbons.

33. The concrete composition of claim 32, further including a superplasticizer in a concentration range of between approximately 0.05% bwoc and 2% bwoc.

34. The concrete composition of claim 32, wherein an early age compressive strength of the concrete composition measured using ASTM C39 at a hydration period of 7 days is between about 4500 psi and 5000 psi.

35. The concrete composition of claim 32, wherein an early age compressive strength of the concrete composition measured using ASTM C39 at a hydration period of 7 days is approximately 35% greater than the compressive strength of concrete including the base composition but not the 3DG carbons.

36. The concrete composition of claim 32, wherein an average diameter of the coarse aggregates is between approximately 0.375 in. and approximately 1.5 in.

37. The concrete composition of claim 32, wherein an average diameter of the fine aggregates is less than approximately 0.37 in.

38. A liquid admixture including:a carbon-based material including three-dimensional graphene flakes (3DG carbons), wherein the 3DG carbons include nano-silica surface functional groups; a surfactant; and water, wherein a concentration of 3DG carbons in the liquid admixture is about 100 g / liter.

39. The liquid admixture of claim 38, wherein the three-dimensional graphene flakes include one or more few layer graphene (FLG), or many layer graphene (MLG).

40. The liquid admixture of claim 38, wherein the three-dimensional graphene flakes include between about 5 and about 15 graphene layers.

41. The liquid admixture of claim 38, wherein the 3DG carbons are characterized by a Raman spectroscopy signature having an ID / IGratio of less than 1.

42. The liquid admixture of claim 38, wherein the 3DG carbons are characterized by a Raman spectroscopy signature having an I2D / IG ratio of less than 1.

43. The liquid admixture of claim 38, wherein an average size of the 3DG carbons is between about 90 nm and about 110 nm.

44. The liquid admixture of claim 38, wherein the surfactant includes one or more of Ethacryl G or sodium dodecylbenzenesulfonate (SDBS).

45. A liquid admixture including: a carbon-based material including three-dimensional graphene flakes (3DG carbons), wherein the 3DG carbons include nano-silica surface functional groups and oxygen functional groups; and water, wherein a concentration of 3DG carbons in the liquid admixture is between about 3 g / liter and about 5 g / liter.

46. The liquid admixture of claim 45, wherein the three-dimensional graphene flakes include one or more few layer graphene (FLG), or many layer graphene (MLG).

47. The liquid admixture of claim 45, wherein the three-dimensional graphene flakes include between about 5 and about 15 graphene layers.

48. The liquid admixture of claim 45, wherein the 3DG carbons are characterized by a Raman spectroscopy signature having an ID / IG ratio of less than 1.

49. The liquid admixture of claim 45, wherein the 3DG carbons are characterized by a Raman spectroscopy signature having an I2D / IGratio of less than 1.

50. The liquid admixture of claim 45, wherein an average size of the 3DG carbons is between about 90 nm and about 110 nm.

51. A grinding aid associated with cement manufacturing processes, wherein the grind aid includes the liquid admixture of claim 38.

52. A grinding aid associated with cement manufacturing processes, wherein the grind aid includes the liquid admixture of claim 45.

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