Carbonation curing method for producing wet cast slag-based concrete products

Abstract

The present invention relates to a method for producing a wet-cast slag-based concrete product, in particular a wet-cast slag-based concrete product cast in a mold and / or in a mold placed in a curing chamber, preconditioned and cured with carbon dioxide, the wet-cast slag-based concrete product optionally being reinforced.

Description

[Technical Field]

[0001] The present invention relates to a method for producing a wet-cast slag-based concrete product, in particular a wet-cast slag-based concrete product cast in a mold and / or in a mold placed in a curing chamber, preconditioned and cured with carbon dioxide, the wet-cast slag-based concrete product optionally being reinforced. [Background technology]

[0002] Metallurgical slag is a large amount of waste material that is typically landfilled. Metallurgical slag can act as a binding material under the right conditions. There is a need to find new uses for metallurgical slag, including steelmaking slag. Summary of the Invention [Means for solving the problem]

[0003] This document describes the development of an optionally reinforced concrete product made from metallurgical slag and carbon dioxide as the primary binder by a wet casting process.

[0004] According to one aspect, there is provided a method for producing a wet-cast slag-based concrete product, the method comprising the steps of: providing a composition for a non-zero slump concrete, the composition comprising a slag-based binder, an aggregate, and water; mixing the slag-based binder, the aggregate, and the water to produce a workable non-zero slump concrete comprising a first water-to-binder weight ratio greater than 0.2; and casting / placing the non-zero slump concrete by transferring / consolidating the non-zero slump concrete into an airtight mold comprising at least one gas pipe / lance; and i) removing gas from the at least one gas lance. the preconditioning step of preconditioning the non-zero slump concrete in the mold using at least one of ii) an air flow / pressurized air, iii) a heater, and iv) a heating element wire embedded in the concrete to produce a conditioned slag-based intermediate having a second water-to-binder weight ratio less than the first water-to-binder weight ratio; the sealing step of sealing the airtight mold; the curing step of curing the conditioned slag-based intermediate using a gas containing carbon dioxide from at least one gas lance to activate the conditioned slag-based intermediate and produce a wet-cast slag-based concrete product; and the curing step of demolding the wet-cast slag-based concrete product.

[0005] According to another aspect, there is provided a method as described herein, wherein the casting step of the non-zero slump concrete does not include pressing / compacting.

[0006] According to yet another aspect, there is provided a method as described herein, wherein after curing, the hollow space in the at least one gas lance is filled with cement grout, steel fiber reinforced cement mortar, and cement paste.

[0007] According to yet another aspect, there is provided a method as described herein, wherein a gas lance may be inserted after the non-zero slump concrete is cast.

[0008] According to yet another aspect, there is provided a method, as herein described, wherein the slag based binder is slag free of or mixed with at least one other binder further selected from the group consisting of fly ash, burnt shale, silica fume, zeolite, GGBF (ground granulated blast furnace) slag, limestone powder, hydraulic cement, and non-hydraulic cement.

[0009] According to yet another aspect, there is provided a method, as described herein, wherein the slag is selected from the group consisting of steelmaking slag, stainless steelmaking slag, basic oxygen furnace sludge, blast furnace sludge, zinc, iron, copper industry by-products, and combinations thereof.

[0010] According to yet another aspect, there is provided a method as herein described, further comprising a reinforcing step of placing a reinforcing material in the gas-tight mold prior to the casting step.

[0011] According to yet another aspect, there is provided a method as described herein, wherein the reinforcement is carbon steel, stainless steel and / or fiber reinforced polymer (FRP) reinforced rebar.

[0012] According to yet another aspect, there is provided a method as described herein, wherein the cumulative calcium silicate content of the slag is at least 20% by weight.

[0013] According to yet another aspect, there is provided a method as described herein, wherein the preconditioning step increases the porosity of the wet cast slag-based concrete by at least 1% by volume.

[0014] According to yet another aspect, there is provided a method as described herein, wherein the non-zero slump concrete has a slump value in the range of 5 mm to 250 mm.

[0015] According to yet another aspect, there is provided a method as described herein, wherein the non-zero slump concrete has a compression modulus test for fresh concrete and should find a value in the range of 0.7 to 1.0.

[0016] According to yet another aspect, there is provided a method as described herein, wherein the steelmaking slag is selected from the group consisting of reduced steelmaking slag, oxidized steelmaking slag, converter steelmaking slag, electric arc furnace slag (EAF slag), basic oxygen furnace slag (BOF slag), ladle slag, fast-cooled steelmaking slag, and slow-cooled steelmaking slag, and combinations thereof.

[0017] According to yet another aspect, there is provided a method as described herein, wherein the wet cast slag-based concrete is further processed into a product selected from the group consisting of precast reinforced and non-reinforced concrete pipes, box culverts, drainage products, paving slabs, floor slabs, traffic barriers, walls, manholes, retaining walls, paving, tiles, and roofing sheets.

[0018] According to yet another aspect, there is provided a method as described herein, wherein the wet-cast slag-based concrete comprises a slag content of at least 5% by weight.

[0019] According to yet another aspect, there is provided a method, as described herein, wherein the non-zero slump concrete further comprises at least one accelerator, retarder, viscosity modifier, air entrainer, foaming agent, ASR (alkali silica reaction) inhibitor, washout prevention agent, rust inhibitor, shrinkage reducing agent, concrete crack reducing agent, plasticizer, superplasticizer, sealant, paint, coating, water reducer, water repellent, efflorescence control agent, polymer powder, polymer latex, and workability retention agent.

[0020] According to yet another aspect, there is provided a method, as described herein, wherein the non-zero slump concrete further comprises at least one of cellulose fibers, glass fibers, micro synthetic fibers, natural fibers, polypropylene (PP) fibers, polyvinyl alcohol (PVA) fibers, and steel fibers.

[0021] According to yet another aspect, there is provided a method as described herein, wherein the CO curing does not include an additional external heat / energy source.

[0022] According to yet another aspect, there is provided a method as described herein, wherein the deformed conditioned slag-based intermediate is cured in a chamber / enclosed space / container / room using a gas containing CO2 at a concentration of at least 5% by volume.

[0023] According to yet another aspect, there is provided a method for producing a wet-cast slag-based concrete product, the method including the steps of providing a non-zero slump concrete composition, the composition comprising a slag-based binder, an aggregate, and water; mixing the slag-based binder, the aggregate, and the water to produce a workable non-zero slump concrete having a first water-to-binder weight ratio greater than 0.2; and casting / placing the non-zero slump concrete by transferring / setting the non-zero slump concrete into an airtight mold, the mold including a mold wall and a plurality of inlets in the mold wall, the plurality of inlets optionally being closed to form a casting cavity for holding a slurry of the non-zero slump concrete. a preconditioning step of preconditioning the non-zero slump concrete in the mold using at least one of i) airflow / pressurized air through multiple inlets in the mold wall, ii) a heater, and iii) heating element wires embedded in the concrete to produce a conditioned slag-based intermediate having a second water-to-binder weight ratio less than the first water-to-binder weight ratio; a sealing step of sealing the mold; and a curing step of curing the conditioned slag-based intermediate with a gas containing carbon dioxide through multiple inlets in the mold wall connected to a gas source to activate the conditioned slag-based intermediate and produce a wet-cast slag-based concrete product, and demolding the wet-cast slag-based concrete product.

[0024] According to yet another aspect, there is provided a method as described herein, wherein the casting step of the non-zero slump concrete does not include pressing / compacting.

[0025] According to yet another aspect, there is provided a method as described herein, wherein at least one perforated tube is optionally inserted through one of the inlets.

[0026] According to yet another aspect, there is provided a method as described herein, wherein at least one perforated tube is inserted into the interior of the gas-tight mold and traverses completely or partially to the opposing mold wall.

[0027] According to yet another aspect, there is provided a method, as herein described, wherein the slag based binder is slag free of or mixed with at least one other binder further selected from the group consisting of fly ash, burnt shale, silica fume, zeolite, GGBF (ground granulated blast furnace) slag, limestone powder, hydraulic cement, and non-hydraulic cement.

[0028] According to yet another aspect, there is provided a method, as described herein, wherein the slag is selected from the group consisting of steelmaking slag, stainless steelmaking slag, basic oxygen furnace sludge, blast furnace sludge, zinc, iron, copper industry by-products, and combinations thereof.

[0029] According to yet another aspect, there is provided a method as herein described, further comprising a reinforcing step of placing a reinforcing material in the gas-tight mold prior to the casting step.

[0030] According to yet another aspect, there is provided a method as described herein, wherein the reinforcement is carbon steel, stainless steel and / or FRP reinforced rebar.

[0031] According to yet another aspect, there is provided a method as described herein, wherein the cumulative calcium silicate content of the slag is at least 20% by weight.

[0032] According to yet another aspect, there is provided a method as described herein, wherein the preconditioning step increases the porosity of the wet cast slag-based concrete by at least 1% by volume.

[0033] According to yet another aspect, there is provided a method as described herein, wherein the non-zero slump concrete has a slump value in the range of 5 mm to 250 mm.

[0034] According to yet another aspect, there is provided a method as described herein, wherein the non-zero slump concrete has a compression modulus test for fresh concrete and should find a value in the range of 0.7 to 1.0.

[0035] According to yet another aspect, there is provided a method as described herein, wherein the steelmaking slag is selected from the group consisting of reduced steelmaking slag, oxidized steelmaking slag, converter steelmaking slag, electric arc furnace slag (EAF slag), basic oxygen furnace slag (BOF slag), ladle slag, fast-cooled steelmaking slag, and slow-cooled steelmaking slag, and combinations thereof.

[0036] According to yet another aspect, there is provided a method as described herein, wherein the wet cast slag-based concrete is further processed into a product selected from the group consisting of precast reinforced and non-reinforced concrete pipes, box culverts, drainage products, paving slabs, floor slabs, traffic barriers, walls, manholes, retaining walls, paving, tiles, and roofing sheets.

[0037] According to yet another aspect, there is provided a method as described herein, wherein the wet-cast slag-based concrete comprises a slag content of at least 5% by weight.

[0038] According to yet another aspect, there is provided a method, as described herein, wherein the non-zero slump concrete further comprises at least one accelerator, retarder, viscosity modifier, air entrainer, foaming agent, ASR (alkali silica reaction) inhibitor, washout prevention agent, rust inhibitor, shrinkage reducing agent, concrete crack reducing agent, plasticizer, superplasticizer, sealant, paint, coating, water reducer, water repellent, efflorescence control agent, polymer powder, polymer latex, and workability retention agent.

[0039] According to yet another aspect, there is provided a method, as described herein, wherein the non-zero slump concrete further comprises at least one of cellulose fibers, glass fibers, micro synthetic fibers, natural fibers, PP fibers, PVA fibers, and steel fibers.

[0040] According to yet another aspect, there is provided a method as described herein, wherein the CO curing does not include an additional external heat / energy source.

[0041] According to yet another aspect, there is provided a method as described herein, wherein the deformed conditioned slag-based intermediate is cured in a chamber / enclosed space / container / room using a gas containing CO2 at a concentration of at least 5% by volume.

[0042] According to yet another aspect, there is provided a method for producing a wet-cast slag-based concrete product, the method including the steps of providing a non-zero slump concrete composition, the composition including a slag-based binder, an aggregate, and water; mixing the slag-based binder, the aggregate, and the water to produce a workable non-zero slump concrete having a first water-to-binder weight ratio greater than 0.2; and casting / placing the non-zero slump concrete by transferring / setting the non-zero slump concrete into a mold, the mold including a mold wall defining an open top surface and a plurality of inlets in the mold wall, the plurality of inlets optionally being closed to retain the workable non-zero slump concrete. a casting / placement step of preconditioning the non-zero slump concrete in the mold using at least one of i) airflow / pressurized air through multiple inlets, ii) a heater, and iii) heating element wires embedded in the concrete to produce a conditioned slag-based intermediate having a second slag-to-water weight ratio less than the first slag-to-water weight ratio; and a curing step of curing the conditioned slag-based intermediate in a chamber / enclosed space / container / room using a gas containing carbon dioxide through multiple inlets in the mold wall and an open top surface to activate the conditioned slag-based intermediate and produce a wet-cast slag-based concrete product, and demolding the wet-cast slag-based concrete product.

[0043] According to yet another aspect, there is provided a method as described herein, wherein the casting step of the non-zero slump concrete does not include pressing / compacting.

[0044] According to yet another aspect, there is provided a method, as herein described, wherein the slag based binder is slag free of or mixed with at least one other binder further selected from the group consisting of fly ash, burnt shale, silica fume, zeolite, GGBF (ground granulated blast furnace) slag, limestone powder, hydraulic cement, and non-hydraulic cement.

[0045] According to yet another aspect, there is provided a method, as described herein, wherein the slag is selected from the group consisting of steelmaking slag, stainless steelmaking slag, basic oxygen furnace sludge, blast furnace sludge, zinc, iron, copper industry by-products, and combinations thereof.

[0046] According to yet another aspect, there is provided a method as herein described, further comprising a reinforcing step of placing a reinforcing material in the mold prior to the casting step.

[0047] According to yet another aspect, there is provided a method as described herein, wherein the reinforcement is carbon steel, stainless steel and / or FRP reinforced rebar.

[0048] According to yet another aspect, there is provided a method as described herein, wherein the cumulative calcium silicate content of the slag is at least 20% by weight.

[0049] According to yet another aspect, there is provided a method as described herein, wherein the preconditioning step increases the porosity of the wet cast slag-based concrete by at least 1% by volume.

[0050] According to yet another aspect, there is provided a method as described herein, wherein the non-zero slump concrete has a slump value in the range of 5 mm to 250 mm.

[0051] According to yet another aspect, there is provided a method as described herein, wherein the non-zero slump concrete has a compression modulus test for fresh concrete and should find a value in the range of 0.7 to 1.0.

[0052] According to yet another aspect, there is provided a method as described herein, wherein the steelmaking slag is selected from the group consisting of reduced steelmaking slag, oxidized steelmaking slag, converter steelmaking slag, electric arc furnace slag (EAF slag), basic oxygen furnace slag (BOF slag), ladle slag, fast-cooled steelmaking slag, and slow-cooled steelmaking slag, and combinations thereof.

[0053] According to yet another aspect, there is provided a method as described herein, wherein the wet cast slag-based concrete is further processed into a product selected from the group consisting of precast reinforced and non-reinforced concrete pipes, box culverts, drainage products, paving slabs, floor slabs, traffic barriers, walls, manholes, retaining walls, paving, tiles, and roofing sheets.

[0054] According to yet another aspect, there is provided a method as described herein, wherein the wet-cast slag-based concrete comprises a slag content of at least 5% by weight.

[0055] According to yet another aspect, there is provided a method, as described herein, wherein the non-zero slump concrete further comprises at least one accelerator, retarder, viscosity modifier, air entrainer, foaming agent, ASR (alkali silica reaction) inhibitor, washout prevention agent, rust inhibitor, shrinkage reducing agent, concrete crack reducing agent, plasticizer, superplasticizer, sealant, paint, coating, water reducer, water repellent, efflorescence control agent, polymer powder, polymer latex, and workability retention agent.

[0056] According to yet another aspect, there is provided a method, as described herein, wherein the non-zero slump concrete further comprises at least one of cellulose fibers, glass fibers, micro synthetic fibers, natural fibers, PP fibers, PVA fibers, and steel fibers.

[0057] According to yet another aspect, there is provided a method as described herein, wherein the CO curing does not include an additional external heat / energy source.

[0058] According to yet another aspect, there is provided a method as described herein, wherein the conditioned slag-based intermediate is cured in a chamber / enclosed space / container / room using a gas containing CO2 at a concentration of at least 5% by volume. [Brief explanation of the drawings]

[0059] [Figure 1] FIG. 1 is a process block diagram illustrating a method for producing a wet-cast slag-based concrete product with casting, preconditioning, and CO2 curing performed in a closed mold with gas pipes / lances according to one embodiment described herein. [Figure 2] FIG. 2 is a front cross-sectional schematic view of the casting, preconditioning and CO2 curing steps in a closed mold according to one embodiment described in FIG. 1 herein. [Figure 3] FIG. 2 is a front cross-sectional schematic view of the casting, preconditioning and CO2 curing steps in a closed mold according to another embodiment described in FIG. 1 herein. [Figure 4] FIG. 1 is a process block diagram illustrating another method for manufacturing a wet-cast slag-based concrete product with casting, preconditioning, and CO2 curing performed in a sealed mold with multiple holes in the mold for gas entry, according to another embodiment described herein. [Figure 5] FIG. 5 is a front cross-sectional schematic diagram of the casting, preconditioning and CO2 curing steps in a closed mold according to one embodiment described herein in FIG. [Figure 6] FIG. 5 is a front cross-sectional schematic view of the casting, preconditioning and CO2 curing steps in a closed mold according to another embodiment described herein in FIG. [Figure 7] FIG. 1 is a process block diagram illustrating a further method for producing a wet-cast slag-based concrete product with casting, preconditioning, and CO2 curing performed in an open-top, non-sealed mold with multiple holes in the mold sidewalls, disposed within a curing chamber or sealed enclosure, according to another embodiment described herein. [Figure 8]FIG. 8 is a front cross-sectional schematic diagram of the casting, preconditioning, and CO curing steps in an unsealed mold in a curing chamber or other gas enclosure according to one embodiment described herein in FIG. DETAILED DESCRIPTION OF THE INVENTION

[0060] Reference is now made to the accompanying drawings, in which:

[0061] Traditionally, virgin sintered Portland cement is used as a binder in concrete production, and wet-cast cement-based precast concrete products are typically cured with heat and steam. In contrast, the wet-cast slag-based concrete of the present invention uses a by-product of a metallurgical plant, and in preferred embodiments, a by-product of a steel mill, as the primary binder, replacing Portland cement, in the production of concrete and precast products. Additionally, carbon dioxide is used as an activator to cure the concrete and is sequestered during the process. In preferred embodiments, no additional heat or steam is required during the CO2 curing process. The proposed wet-cast slag-based concrete products, optionally reinforced, may exhibit comparable or superior mechanical properties and durability compared to conventional cement-based precast products, while reducing greenhouse gas emissions into the atmosphere during their production. The proposed invention also reduces natural resource consumption because conventional cement is not used in slag-based concrete products and slag-based concrete products require a lower aggregate content. Finally, the production of optionally reinforced wet-cast slag-based concrete products according to the proposed invention has the potential to increase production rates in precast concrete production facilities.

[0062] [material] The primary binder in the production of wet cast slag-based concrete 56 is, in a preferred embodiment, slag derived from the production of steel or stainless steel. Other by-product materials from the production of zinc, iron, and copper can also be considered slag.

[0063] Various slags can be collected from steel plants that practice different steel production processes. Among the types of slag that can be incorporated as the primary binder in the production of the wet-cast slag-based concrete described herein are stainless steel slag, reduced steelmaking slag, oxidized steelmaking slag, converter steelmaking slag, electric arc furnace slag (EAF slag), basic oxygen furnace slag (BOF slag), ladle slag, fast-cooled steelmaking slag, slow-cooled steelmaking slag, basic oxygen furnace sludge, blast furnace sludge, and combinations thereof.

[0064] In a preferred embodiment, the slag has a calcium oxide weight content of more than 10%, preferably more than 15%, preferably more than 20%. In a preferred embodiment, the silica oxide weight content is more than 6%, preferably more than 8%, preferably more than 12%. In a preferred embodiment, the slag has a total iron oxide content of less than 40%, preferably less than 30%. In a preferred embodiment, the steelmaking slag has a cumulative calcium silicate content of at least 20% and a free lime concentration of less than 15%, preferably less than 7%. In a preferred embodiment, the slag has a bulk density of 1.0 to 2.0 g / cm. 3 The apparent density is in the range of 2.0 to 6.0 g / cm 3 can vary.

[0065] The slag may be ground to a smaller size (if necessary) before being incorporated into the wet-cast slag-based concrete mix described herein. Grinding of the slag can be accomplished using any mechanical machine, such as a ball mill, rod mill, autogenous mill, SAG mill, pebble mill, high-pressure grinding roll, VSI, or tower mill. The grinding process can be carried out wet or dry. While a dry size reduction process is preferred, if a wet process is selected to grind the slag, the ground slag can be fully or semi-dried after grinding. Passing the slag through a classifier is an alternative option to obtain slag with a smaller particle size / grain size. Classifiers used are known in the art and include, but are not limited to, screens, centrifuges, and cyclones.

[0066] The crushed or classified slag in preferred embodiments passes through mesh #10 (2000 microns), preferably mesh #50 (297 microns), preferably mesh #200 (74 microns), and preferably mesh #400 (37 microns), each of which can be used alone or in combination with at least one other binder. Sieves may be utilized to screen the slag either after crushing or before crushing. Thus, one or a combination of crushing and screening methods can be performed to obtain slag with an appropriate particle size distribution.

[0067] The slag must be at least 50m 2 / kg, preferably 150m / kg, preferably at least 200m 2 In a preferred embodiment, the slag in the slag-based wet concrete has 50 percent of the slag less than 200 microns (D50=200 μm), preferably less than 150 microns (D50=150 μm), preferably less than 100 microns (D50=100 μm), preferably less than 50 microns (D50=50 μm), preferably less than 25 microns (D50=25 μm), preferably less than 10 microns (D50=10 μm).

[0068] The free lime content of the slag may be reduced by any standard method known in the art before incorporation into the mix. Alternatively, the slag may be first aged to reduce the free calcium oxide (free lime) content of the slag and then incorporated into the mix. The slag content of wet-cast slag-based concrete should be 5% or more by weight of the concrete, preferably 20% or more by weight of wet-cast slag-based concrete or non-zero slump concrete compositions.

[0069] The slag-based binder may further comprise slag alone (i.e., slag without another binder), or a combination of slag with at least one other binder, such as a cementitious / pozzolanic material. As an example, slag can be mixed with at least one other binder to produce a slag-based binder further comprising fly ash, burnt shale, silica fume, zeolite, GGBF (ground granulated blast furnace) slag, limestone powder, hydraulic cement, non-hydraulic cement, and combinations thereof.

[0070] Various types of aggregates, including natural or artificial normal-weight and lightweight aggregates, can be incorporated into slag-based wet concrete products as fillers in the production of wet-cast slag-based concrete products. Examples of potential lightweight aggregates include natural lightweight aggregates (e.g., pumice), expanded clay aggregates, expanded shale aggregates, and expanded iron slag aggregates. Other usable aggregates include crushed stone, manufactured sand, gravel, sand, recycled aggregate, granite, limestone, quartz, chalk dust, marble dust, quartz sand, and artificial aggregates. These aggregates are incorporated into the mix as fine and / or coarse aggregates. The aggregate content can be as high as 90% by weight of the wet-cast slag-based concrete or non-zero slump concrete composition.

[0071] The proposed slag-based wet concrete is a workable concrete. To produce wet concrete (as opposed to zero-slump concrete), sufficient water should be added to the dry ingredients. The required water content depends on the particle size of the slag selected as the primary binder, the moisture content of the aggregate, and the binder content. Finer ground slag absorbs more water and therefore requires a higher water content to produce wet concrete. The water-to-binder ratio can be 0.9, preferably 0.8, preferably 0.7, preferably 0.6, preferably 0.5, preferably 0.4, preferably 0.3, or preferably 0.2. For example, for a binder consisting solely of slag with a D50 of 25 microns, a water-to-binder ratio of 0.4 can result in workable wet concrete. If the aggregate is very wet, adding water to the mix may not be necessary.

[0072] Chemical admixtures can be added to the mixture as needed to achieve specific properties. Possible chemical admixtures include, but are not limited to, accelerators, retarders, viscosity modifiers, air entrainers, foaming agents, alkali silica reaction (ASR) inhibitors, washout inhibitors, rust inhibitors, shrinkage reducers, crack reducers, plasticizers, superplasticizers, water reducers, water repellents, efflorescence control agents, and workability retention agents.

[0073] If desired, fibers can be added to slag-based wet concrete. One or a combination of cellulose fibers, glass fibers, micro-synthetic fibers, natural fibers, PP fibers, PVA fibers, and steel fibers can be incorporated into the mixture.

[0074] "Zero slump concrete" is defined as concrete with a stiff or very dry consistency that exhibits no measurable slump after removal of the slump cone. A standard exemplary slump test is ASTM C143 for hydraulic cement concrete. Non-zero slump concrete is concrete that is neither stiff nor very dry in consistency that exhibits a measurable slump after removal of the slump cone by a test such as ASTM C143. Slump values ​​herein are evaluated using the method described in the ASTM C143 standard.

[0075] The wet-cast slag-based concrete manufacturing process can be adapted to produce a variety of products, including, but not limited to, precast reinforced concrete pipe, box culverts, drainage products, paving slabs, floor slabs, traffic barriers, walls, manholes, precast non-reinforced concrete (plain) paving, retaining walls, tiles, and roofing sheets. Products shall meet local and national standards and regulations.

[0076] Referring to the figures, Figures 1, 4, and 7 presented herein illustrate three embodiments of process flow diagrams for manufacturing wet-cast slag-based concrete products. The three-digit reference numbers used in Figures 1, 4, and 7 include a single-digit prefix 1XX, 2XX, and 3XX, respectively. The two-digit reference number suffixes represent the same components in each of Figures 1, 4, and 7. That is, for example, reference numbers 120, 220, and 320 represent the casting unit operation in each of the process flow diagrams, specifically, in each of Figures 1, 4, and 7, respectively.

[0077] A) Closed mold with gas pipe / lance passing through the top / lid of the mold Referring to FIG. 1, a method 101 for producing a wet-cast slag-based concrete product 156 is outlined, with steps including casting in a sealed, gas-tight mold with at least one gas pipe / lance, preconditioning, and CO2 curing.

[0078] (i) Production of wet-cast slag-based concrete 156 The wet-cast slag-based concrete 156 method 101 provides a non-zero slump concrete 116 composition and begins by uniformly mixing 110 all components of the composition, including, but not limited to, slag 111 and any at least one other binder 113 (i.e., slag alone or slag and at least one other binder) that, when mixed, provides a slag-based binder 114, aggregate 115, chemical admixtures 117, fibers 119, and water 105. The water-to-binder ratio of the wet-cast slag-based concrete 156 used in the present invention should be higher than the water content of dry-cast or zero-slump concrete. In a preferred embodiment, the mixed non-zero slump concrete 116 has a first water-to-binder weight ratio greater than 0.2, preferably 0.25, preferably 0.3, preferably 0.35, preferably 0.4, preferably 0.45, preferably 0.5, preferably 0.55, preferably 0.6, or preferably 0.65. The terms "water to slag-based binder weight ratio" and "water to binder weight ratio" are equivalent.

[0079] The non-zero slump concrete 116 preferably has a slump range of 5 to 250 mm. The non-zero slump concrete 116 is preferably workable for at least 5 minutes. Mixing 110 should ensure that the non-zero slump concrete 116 shows no signs of separation or bleeding. In preferred embodiments, the non-zero slump concrete 116 has a compression modulus test range of 0.7 to 1.0. The temperature of the non-zero slump concrete 116 prior to casting is preferably 0°C to 30°C. In preferred embodiments, the fresh non-zero slump concrete 116 should have an air void content of no more than 15% by volume of concrete, as measured by any conventional method (an exemplary standard test is ASTM C231 for Air Content of Freshly Mixed Concrete by the Pressure Method). The compression modulus test is described in BS 1881-103:1993 and BS EN 12350-4:2009 (BS EN 12350-4:2009, Testing fresh concrete Part 4: Degree of compatibility). The properly mixed non-zero slump concrete 116 is now ready to be transferred to the casting 120.

[0080] (ii) reinforcement In a preferred embodiment, before casting the non-zero slump concrete 116, a mold is prepared and, if necessary, reinforcement materials such as carbon steel, stainless steel, and / or FRP reinforcing bars are placed in the airtight mold. The diameter of the reinforcing bars can vary from 5 mm to 60 mm, and the yield strength can range from 100 MPa to 2100 MPa. The reinforcement materials are designed in accordance with regulations and standards.

[0081] (iii) Casting 120, Placement The punched hollow pipes / lances are placed in an airtight mold. Their geometric shape can be circular or rectangular, with a cross-sectional area of ​​10,000 mm per pipe. 2The diameter of the pipe / lance is less than 10 mm, and the wall thickness is greater than 0.5 mm. The pipe / lance material can be carbon steel, stainless steel, or alloy steel with a carbon content of 0.05% to 1.4%, and the pipe / lance has a yield strength of 100 MPa to 2100 MPa. The pipe / lance can be punched with a machine tool, a handheld device, or any tool that creates holes by shearing. In any embodiment, the pipe / lance may be made of a permeable screen / mesh material suitable for its function. The maximum hole dimension should be 10 mm, preferably 5 mm, or preferably 1 mm. The hole spacing, both vertically and horizontally, should not exceed 300 mm, preferably 200 mm, preferably 100 mm, or preferably 50 mm. In another example, the punched hollow pipe is made of aluminum or plastic. The pipe / lance is used to transfer gas into the non-zero slump concrete 116.

[0082] The raw, prepared non-zero slump concrete 116 is transferred by suitable means and cast into a mold prepared by any known method in the art. The mold can be made of steel, iron, aluminum, plastic, FRP, or other materials. The mold should be airtight and is sealed using a lid designed to cover and enclose the top of the mold with one of the possible mold materials or an airtight fabric. This lid is attached to the body of the mold with hinges, clamps, and / or bolts. Several precision-machined holes are cut into the lid to allow a punched hollow pipe / lance to pass through the mold lid. In another example, the pipe / lance can be inserted into the concrete / mold immediately after the concrete is cast. The lid can be initially attached to the mold before casting, or in another example, it can be attached to the mold after the concrete is cast.

[0083] The mold should be pre-lubricated prior to casting to facilitate the demolding process 130. The wet cast concrete or slag-based intermediate body 126 is hardened in the mold in 120 seconds or less by an internal or external vibrator. The wet cast concrete or slag-based intermediate body 126 does not need to be pressed or compacted in the mold; that is, the method in preferred embodiments does not include pressing or compacting. The moisture content of the slag-based intermediate body 126 must be reduced.

[0084] (iv) Advance adjustment140 The preconditioning 140 process step reduces the moisture content of the non-zero slump concrete 116 by removing water 142. Preconditioning can be performed in at least one of two ways. The first method involves introducing an airflow 141 through a hollow pipe / lance (FIG. 2). Alternatively, the airflow can be pressurized air. The preconditioning step does not require a lid. This preconditioning step continues until the initial water-to-binder content is reduced by up to 90%, preferably 80%, preferably 70%, preferably 60%, preferably 50%, preferably 40%, preferably 30%, preferably 20%, or preferably 10% as water vapor 142 escapes from the mold. The second method, in a preferred embodiment, uses heating element wires 143 embedded in the concrete. These wires are placed in the mold before the concrete is cast (FIG. 3). The wires may also be placed on a steel frame at 300 mm intervals along the height of the mold. The heating wires and frame are left in the concrete when the concrete is cast and after curing. An electric current can then be passed through the frame and wires. Alternatively, heaters can be used that can be installed over the exterior of the mold, such as underfloor heating mats or drum heaters. These elements heat the mold walls, ultimately increasing the evaporation process and reducing the moisture content of the concrete. The two methods can also be combined to include both drying air 141 and heating 143.

[0085] The preconditioning 140 step continues until the initial water to binder content is reduced by 90%, preferably 80%, preferably 70%, preferably 60%, preferably 50%, preferably 40%, preferably 30%, preferably 20%, preferably 10%, preferably 2% and a slag-based intermediate 126 is produced.

[0086] The increase in porosity determined in relation to the concrete volume produced by any of the above preconditioning methods in concrete is 70%, preferably 60%, preferably 50%, preferably 40%, preferably 30%, preferably 20%, preferably 10% or preferably 5% or preferably 1% of the concrete volume. After any method, the mould is sealed, taking note of the opening through which the hollow gas pipe / lance protrudes, the lid is closed and the mould is inspected for air tightness.

[0087] At the end of the preconditioning 140 process, the residual water in the concrete must be no less than 5% by weight of the initial water content, forming a conditioned slag-based intermediate 146 having a second water-to-binder weight ratio that is less than the first water-to-binder weight ratio of the non-zero slump concrete 116. After completion of the preconditioning step 140, the mold is hermetically sealed.

[0088] (v) CO2 activation / curing 150 The conditioned slag-based intermediate 146 is contacted with carbon dioxide, CO2, or a gas mixture thereof. Carbon dioxide 151 gas is introduced to cure the conditioned slag-based intermediate 146 at ambient temperature through a punched hollow pipe / lance at a purity of 5%, preferably 10%, preferably 20%, preferably 30%, preferably 40%, preferably 50%, preferably 60%, preferably 70%, preferably 80%, preferably 90%, or preferably 99.5%. The gauge pressure in the chamber / enclosure / vessel / room is gradually increased in the range of 0.1 psi to 100 psi. Although not shown, it is understood that some gas may escape the CO2 activation / curing step.

[0089] In this embodiment of the invention, the sealed mold also acts as a curing chamber. The mold remains pressurized with carbon dioxide for at least 10 minutes, although the CO2 curing process can continue for up to 48 hours. The temperature inside the mold increases by at least 1°C as a result of the exothermic accelerated curing reaction—the "CO2 activation process." At the end of the activation process, any remaining CO2 is vented and the lid is opened. The pipes / lances can be left in the concrete or removed from the concrete. It is understood that at least one gas lance leaves a hollow space that can be filled with cement grout, steel fiber reinforced cement mortar, cement paste, or polymer concrete. Filling of this gas lance occurs after CO2 curing or demolding.

[0090] (vi) Demoulding 130 Demolding occurs immediately after or after the CO2 activation process. The excess length of the punched hollow pipe / lance (if remaining in the concrete) is cut off and the hollow pipe or the created space is filled 155 with cement grout, steel fiber reinforced cement mortar, cement paste, polymer concrete or a combination thereof. The cement or polymer based filler material is allowed to cure for at least one hour.

[0091] Demolding 130 produces wet cast slag-based concrete 156.

[0092] B) A sealed mold with holes in the side wall of the mold Referring to FIG. 4, a method 201 for producing a wet-cast slag-based concrete product 256 is outlined, with steps including casting in a sealed mold with multiple holes in the mold for gas entry, preconditioning, and CO2 curing.

[0093] (i) Production of wet-cast slag-based concrete 256 The method 201 for manufacturing the wet-cast slag-based concrete 256 begins similarly to the method described above for the wet-cast slag-based concrete 156. The composition of the non-zero slump concrete 216 is uniformly mixed 210 with the components of the composition, again including, but not limited to, slag 211 and optionally at least one other binder 213 (providing the slag-based binder 214), aggregate 215, chemical admixtures 217, fibers 219, and water 205. All properties of the wet-cast slag-based concrete 256 are the same as those described above for the wet-cast slag-based concrete 256.

[0094] Mix 210 again ensures that the non-zero slump concrete 216 shows no signs of separation or bleeding.

[0095] (ii) reinforcement As previously described in FIG. 1 for wet cast slag-based concrete 156, wet cast slag-based concrete 256 optionally includes an airtight mold prepared with reinforcement as previously described.

[0096] (iii) Casting 220, Placement The mold for method 201 can again be made of steel, iron, aluminum, plastic, or FRP. The mold is preferably airtight and can be sealed using a lid designed with a top cover made of the materials described above after the non-zero slump concrete 256 is poured into it. The airtight mold lid is reattached to the mold body using a combination of hinges, clamps, and / or bolts. This embodiment of method 201 does not require the special openings in the mold lid for the gas pipes / lances of the previous embodiments.

[0097] Two different types of airtight molds are presented for two different construction methods of two embodiments of method 201. In the schematic embodiment of FIG. 5, the mold has multiple small holes in the side walls. The maximum diameter of these holes must not exceed 10 mm. The spacing between adjacent holes must not exceed 300 mm both vertically and horizontally. In a second embodiment of method 201 shown in FIG. 6, the airtight mold has multiple small but large holes in the side walls (maximum spacing between large holes is 500 mm, 400 mm, 300 mm, preferably 200 mm, preferably 100 mm, preferably 50 mm), which contain at least one perforated pipe passing through the large mold side wall hole. The diameter of the large hole in the mold wall must be in the range of 10 mm to 200 mm. The hole is optionally closed to hold the fresh non-zero slump concrete. The perforated pipe placed in the mold wall is made of steel, FRP, stainless steel, plastic, or aluminum. These perforated tubes optionally traverse the interior of the mold until they reach the opposite side or terminate at a certain distance within the mold. The cross section, spacing, and area of ​​the tubes correspond to the holes in the side wall. The perforated tubes are gas permeable and define a number of orifices, preferably with a maximum spacing of 30 mm between each orifice. The perforated tubes may be inserted into the interior of the gas-tight mold and traverse completely or partially to the opposite mold wall. The hollow space left in the perforated tubes and the holes in the side wall can be sealed by methods known to those skilled in the art.

[0098] The perforated pipes placed in the mold walls may have wall thicknesses exceeding 0.5 mm. The perforated pipes can be made of carbon steel, stainless steel, or alloy steel with a carbon content of 0.05% to 1.4% and a strength of 100 MPa to 2100 MPa. The perforated pipes can be punched with a mechanical tool, a handheld device, or any tool that creates holes by shearing, or with a suitable permeable screen material. The maximum hole size should be 10 mm, preferably 5 mm, or preferably 1 mm. In another example, the perforated pipes are made of aluminum or plastic. The perforated pipes are used to transfer gases into the non-zero slump concrete 216. The perforated pipes can be placed in the mold before the concrete is cast, or inserted through larger holes after the concrete is cast.

[0099] The raw, prepared non-zero slump concrete 216 is transferred to a mold prepared by any known method in the art. The mold, which should again be airtight, is sealed using a lid designed to cover and enclose the top of the mold with one of the possible mold materials or an airtight fabric. This lid is attached to the body of the mold with hinges, clamps, and / or bolts.

[0100] The mold is again pre-lubricated prior to casting to facilitate the demolding process 230. The wet cast concrete or slag-based intermediate body 226 is hardened in the mold in 120 seconds or less by internal or external vibrators. The wet cast concrete or slag-based intermediate body 126 does not need to be pressed or compacted in the mold; that is, the method in preferred embodiments does not include pressing or compacting. The moisture content of the slag-based intermediate body 226 must be reduced.

[0101] (iv) Pre-adjustment240 The preconditioning 240 process step again reduces the moisture content of the slag-based intermediate body 226. Preconditioning can be performed in at least one of two ways. First, airflow 241 is introduced through multiple openings in the mold wall (FIG. 5). In another example, the airflow can be pressurized air. This preconditioning step, as in method 101, reduces the initial water-to-binder content. In another embodiment, heating elements / wires 243 are used. These wires can be placed outside the mold before casting the wet-cast slag-based concrete 226 (FIG. 5) or embedded within the slag-based intermediate body 226. The wires can be placed on a steel frame at 300 mm intervals along the height of the mold. The heating elements / wires can also be floor heating mats or drum heaters installed to cover the exterior of the mold. These elements heat the mold walls, ultimately increasing the evaporation process and reducing the moisture content of the slag-based intermediate body 226. The two embodiments for reducing humidity can also be combined to simultaneously use both drying and heating 243 of the air 241 .

[0102] The preconditioning 240 step continues to release water vapor 242 until the initial water to binder content is reduced as in step 140 .

[0103] The increase in porosity determined relative to the volume of concrete produced by any of the above preconditioning methods in concrete is 70%, preferably 60%, preferably 50%, preferably 40%, preferably 30%, preferably 20%, preferably 10% or preferably 5% or preferably 1% of the volume of concrete. After any embodiment, the mold lid is closed and the mold is inspected for airtightness, taking note of the opening in the mold wall for the perforated tube in the case of the embodiment shown in Figure 6.

[0104] At the end of the preconditioning 240 process, the residual water in the concrete must be no less than 5% by weight of the initial water content, forming a conditioned slag-based intermediate 246 having a second water-to-binder weight ratio that is less than the first water-to-binder weight ratio of the non-zero slump concrete 216. After completion of the preconditioning step 240, the mold is hermetically sealed.

[0105] (v) CO2 activation / curing 250 The conditioned slag-based intermediate 246 in the mold is contacted with carbon dioxide, CO, or a gas containing CO. A hole in the side of the mold is connected to a CO source via a pipe. Carbon dioxide 251 gas is introduced to cure the conditioned slag-based intermediate 146, with CO being 5%, preferably 10%, preferably 20%, preferably 30%, preferably 40%, preferably 50%, preferably 60%, preferably 70%, preferably 80%, preferably 90%, or preferably 99.5% pure, and injected into the conditioned slag-based intermediate 246 at ambient temperature through a sidewall opening in the mold. The gauge pressure of the gas is gradually increased, optionally ranging from 0.1 psi to 100 psi. Although not shown, it is understood that some gas may escape the mold during the CO activation / curing step.

[0106] In this embodiment of the invention, the sealed mold also acts as a curing chamber. The mold remains pressurized with carbon dioxide for at least 10 minutes, but the CO2 curing process can continue for up to 48 hours. The temperature inside the mold increases by at least 1°C as a result of the exothermic accelerated curing reaction - the "CO2 activation process." At the end of the activation process, any remaining CO2 is vented and the lid is opened.

[0107] (vi) Demoulding 230 Demolding occurs immediately or shortly after the completion of the CO activation process. The perforated pipe can be left in the concrete or removed from the concrete. Any excess length of pipe from the mold sidewalls is cut off and the space is filled 255 with cement grout, steel fiber reinforced cement mortar, cement paste, polymer concrete, or a combination thereof. The cement or polymer-based filler material in the pipe is allowed to cure for at least one hour.

[0108] Demolding 230 produces wet cast slag-based concrete 256.

[0109] C) Open mold with gas supply to the curing chamber or enclosure 7, there is shown a method 301 for producing a wet-cast slag-based concrete product 356, which includes casting, preconditioning and CO2 curing steps in an open mold with multiple mold cavities, placed in a curing chamber or other enclosure. The enclosure can be at least one of a chamber, an enclosed space, a container and a room.

[0110] (i) Production of wet-cast slag-based concrete 356 Similar to methods 101 and 201, method 301 for producing wet-cast slag-based concrete 356 provides a composition for non-zero slump concrete 316 and begins with uniformly mixing 310 all components of the composition, including, but not limited to, slag 311 and optionally at least one other binder 313 (providing slag-based binder 314), aggregate 315, chemical admixtures 317, fibers 319, and water 305. The water-to-binder ratio of wet-cast slag-based concrete 356 used in the present invention should be higher than the water content of dry-cast or zero-slump concrete. In preferred embodiments, the mixed non-zero-slump concrete 316 has a first water-to-binder weight ratio greater than 0.2, preferably 0.25, preferably 0.3, preferably 0.35, preferably 0.4, preferably 0.45, preferably 0.5, preferably 0.55, preferably 0.6, or preferably 0.65. The terms "water to slag-based binder weight ratio" and "water to binder weight ratio" are equivalent.

[0111] The non-zero slump concrete 316 preferably has a slump range of 5 to 250 mm. The non-zero slump concrete 316 is preferably workable for at least 5 minutes. Mixing 310 should ensure that the non-zero slump concrete 316 shows no signs of separation or bleeding. In preferred embodiments, the non-zero slump concrete 316 has a compression modulus test range of 0.7 to 1.0. The temperature of the non-zero slump concrete 316 prior to casting is preferably 0°C to 30°C. In preferred embodiments, the fresh non-zero slump concrete 316 should have an air void content of no more than 15% by volume of concrete, as measured by any conventional method (an exemplary standard test is ASTM C231 for Air Content of Freshly Mixed Concrete by the Pressure Method). The compression modulus test is described in BS 1881-103:1993 and BS EN 12350-4:2009 (BS EN 12350-4:2009, Testing fresh concrete Part 4: Degree of compatibility). The properly mixed non-zero slump concrete 316 is now ready to be transferred to the casting 320.

[0112] (ii) reinforcement In a preferred embodiment, before casting the non-zero slump concrete 316, a mold is prepared and, if necessary, reinforcement materials such as carbon steel, stainless steel, and / or FRP reinforcing bars are placed in the mold. The diameter of the reinforcing bars can vary from 5 mm to 60 mm, and the yield strength can range from 100 MPa to 2100 MPa. The reinforcement materials are designed in accordance with regulations and standards.

[0113] (iii) Casting 320, Placement The sidewalls of the mold contain a plurality of openings. Interestingly, the mold for this embodiment of method 301 is neither airtight nor lidless. The mold may be made of steel, iron, aluminum, plastic, or FRP. Alternatively, an existing concrete mold may be adjusted by drilling holes in the wall. The plurality of openings are preferably 1-500 mm in diameter, or the openings are at least 1 mm. 2 The mold may have any shape with a surface area of ​​0.05 mm or less. The openings in the mold sidewalls allow air (and subsequently CO2) to enter the mold while it is in the curing chamber or other enclosure. As shown in FIG. 8, the space between each of the openings in any direction is preferably less than 1000 mm. Optionally, the openings can be temporarily filled with plugs to prevent the green non-zero slump concrete 316 from leaking out of the mold during transfer; rubber plugs are a common choice. If plugs are used, they should be removed before allowing gas passage for the preconditioning step 340 and the carbonation curing step 350, respectively.

[0114] The fresh prepared non-zero slump concrete 316 is transferred by suitable means and cast into molds prepared by any known method in the art.

[0115] The mold should be pre-lubricated prior to casting to facilitate the demolding process 330. The wet cast concrete or slag-based intermediate body 326 is hardened in the mold in 120 seconds or less by internal or external vibrators. The wet cast concrete or slag-based intermediate body 126 does not need to be pressed or compacted in the mold; that is, the method in preferred embodiments does not include pressing or compacting. The moisture content of the slag-based intermediate body 326 must be reduced.

[0116] (iv) Pre-adjustment 340 The preconditioning 340 process step reduces the moisture content 342 (now of the slag-based intermediate 326). Preconditioning can be accomplished in at least one of two ways. The first method involves introducing a stream of air or pressurized air 341 inside or outside the curing chamber or enclosure. A further embodiment method uses heating elements / wires 343. These wires are placed on or near the mold walls before the concrete 320 is cast (FIG. 7). Optionally, the wires are placed on a steel frame at 300 mm intervals along the height of the mold. The heating wires and frame are left in the concrete during casting and after curing. An electric current can then be passed through the frame and wires. The heating elements / wires can also be underfloor heating mats or drum heaters placed over the exterior of the mold. These elements heat the mold walls, ultimately increasing the evaporation process and reducing the moisture content of the concrete. The two methods can also be combined to include both drying air 341 and heating 343.

[0117] The preconditioning 340 step continues until the initial water to binder content is reduced by up to 90%, preferably 80%, preferably 70%, preferably 60%, preferably 50%, preferably 40%, preferably 30%, preferably 20%, preferably 10% or preferably 2%.

[0118] The increase in porosity determined relative to the volume of concrete produced by any of the above preconditioning methods in concrete is 70%, preferably 60%, preferably 50%, preferably 40%, preferably 30%, preferably 20%, preferably 10%, or preferably 5%, or preferably 1% of the volume of concrete. After either method, attention / inspection of multiple openings ensures that air is in contact with the slag-based intermediate 326.

[0119] At the end of the preconditioning 340 process, the residual water in the concrete must be not less than 5% by weight of the initial water content, forming a conditioned slag-based intermediate 346 having a second water-to-binder weight ratio that is less than the first water-to-binder weight ratio of the non-zero slump concrete 316.

[0120] (v) CO2 activation / curing 350 The conditioned slag-based intermediate 346 is contacted with carbon dioxide, CO, or a gas containing CO from a curing chamber or suitable gas enclosure. Carbon dioxide 351 gas is introduced to cure the conditioned slag-based intermediate 346 at ambient temperature, at a purity of 5%, preferably 10%, preferably 20%, preferably 30%, preferably 40%, preferably 50%, preferably 60%, preferably 70%, preferably 80%, preferably 90%, or preferably 99.5% from the atmosphere of the curing chamber or enclosure through multiple openings in the sidewall of the mold. The gauge pressure of the chamber / enclosure / container / room is gradually increased, ranging from 0.1 psi to 100 psi. Although not shown, it is understood that some gas may escape from the mold during the CO activation / curing step.

[0121] In this embodiment of the invention, the mold remains pressurized with carbon dioxide for at least 10 minutes, although the CO2 curing process can continue for up to 48 hours. The temperature within the mold increases by at least 1°C as a result of the exothermic accelerated curing reaction - i.e., the "CO2 activation process." At the end of the activation process, any remaining CO2 is vented from the curing chamber or enclosure.

[0122] FIG. 8 illustrates the casting 320, preconditioning 340, and CO2 curing 350 steps in a cross-sectional front view of an unsealed mold according to one embodiment of the method 301 described herein in FIG.

[0123] (vi) Demoulding 330 Demolding occurs immediately after or immediately following the CO2 activation process.

[0124] Demolding 330 produces wet cast slag-based concrete 356 .

[0125] Some parameters for producing one cubic meter of concrete according to the method described herein are given below.

[0126] Steel slag content = 600 kg, first water / binder ratio = 0.35, slump = 5 mm, preconditioning method = air flow

[0127] Steel slag content = 500 kg, limestone powder = 50 kg, first water / binder ratio = 0.55, slump = 200 mm, preconditioning method = air flow

[0128] Stainless steel slag content = 350 kg, first water / binder ratio = 0.45, polymer powder = 50 kg, hydraulic cement = 30 kg, fly ash = 200 kg, slump = 100 mm, preconditioning method = pressurized air

[0129] Steel slag content = 400 kg, non-hydraulic cement = 100 kg, first water / binder ratio = 0.4, preconditioning method = heater

[0130] Stainless steel slag content = 480 kg, first water / binder ratio = 0.45, silica fume = 20 kg, rust inhibitor = 5 kg, preconditioning method = heating element wire

[0131] Steel slag content = 650 kg, first water / binder ratio = 0.45, air-entraining admixture = 2 liters, slump = 120 mm, preconditioning method = heating element wire

[0132] Steel slag content = 700 kg, first water / binder ratio = 0.45, steel fiber = 80 kg, viscosity adjusting admixture = 1 liter, slump = 50 mm, preconditioning method = air flow

[0133] Steel slag content = 1200 kg, first water / binder ratio = 0.30, superplasticizer = 15 liters, water repellent = 5 liters, slump = 150 mm, preconditioning method = pressurized air

[0134] The foregoing description is merely exemplary, and those skilled in the art will understand that changes can be made to the described embodiments without departing from the disclosed invention. Still other modifications that fall within the scope of the invention will be apparent to those skilled in the art in light of a review of the present disclosure, and such modifications are intended to fall within the scope of the appended claims.

Claims

1. 1. A method for producing a wet-cast slag-based concrete product, said method comprising: 1) providing a slag-based binder, aggregate, and water; 2) mixing the slag-based binder, the aggregate, and the water to produce a workable non-zero slump concrete composition comprising a first water-to-slag-based binder weight ratio greater than 0.2 and having a slump value in the range of 5 mm to 250 mm and a compaction coefficient in the range of 0.7 to 1.0; 3) a) a casting step of casting and / or placing the non-zero slump concrete composition by transferring and / or hardening the non-zero slump concrete composition into an airtight mold, the airtight mold comprising at least one gas pipe and / or lance; or b) a casting step of casting and / or placing the non-zero slump concrete composition by transferring and / or hardening the non-zero slump concrete composition into an airtight mold, the casting step further comprising inserting at least one gas pipe and / or lance into the non-zero slump concrete composition; or c) a casting step of casting and / or placing the non-zero slump concrete composition by transferring and / or hardening the non-zero slump concrete composition into an airtight mold, the mold comprising a mold wall and a plurality of inlets in the mold wall, the plurality of inlets being optionally closed to retain the non-zero slump concrete composition; or d) casting and / or placing the non-zero slump concrete composition by transferring and / or solidifying the non-zero slump concrete composition into a mold, the mold including a mold wall defining an open top surface and a plurality of inlets in the mold wall, the plurality of inlets optionally being closed to retain the non-zero slump concrete composition; 4) preconditioning the non-zero slump concrete composition in the mold using at least one of: i) airflow and / or pressurized air from the at least one gas pipe and / or lance or through the plurality of inlets in the mold wall; ii) a heater; and iii) a heating element wire embedded in the non-zero slump concrete composition to produce a preconditioned slag-based intermediate body comprising a second water to slag-based binder weight ratio less than the first water to slag-based binder weight ratio. 5) when the casting step is casting step 3a), 3b) or 3c), a sealing step of sealing the gas-tight mold; 6) a)-b) when the casting step is casting step 3a) or 3b), from the at least one gas pipe and / or lance, or c) through the inlets in the mold wall when the casting step is casting step 3c); or d) when the casting step is casting step 3d), curing the pre-conditioned slag-based intermediate with a gas containing carbon dioxide in a chamber / enclosed space / container / room through the multiple inlets in the mold wall and the open top surface to produce a molded wet-cast slag-based concrete product; and 7) demolding the molded wet-cast slag-based concrete product to provide the wet-cast slag-based concrete product.

2. 10. The method of claim 1, wherein the casting step of the non-zero slump concrete composition does not include pressing / compaction.

3. A method as described in claim 1 or 2, wherein the curing step is curing step 6a) or 6b), and further comprising, after the curing step, a step of filling hollow spaces in the at least one gas pipe and / or lance with cement grout, steel fiber reinforced cement mortar and / or cement paste.

4. A method according to any one of claims 1 to 3, wherein the casting step is casting step 3a) and the gas pipe and / or lance are inserted after casting the non-zero slump concrete composition.

5. 3. The method of claim 1 or 2, wherein in the curing step 6c), a perforated tube is inserted through at least one of the plurality of inlets in the mold wall.

6. 6. The method of claim 5, wherein the perforated tube is inserted into the interior of the gas-tight mold and traverses completely or partially to the opposite mold wall.

7. 7. The method according to any one of claims 1 to 6, wherein the slag-based binder is slag free of or mixed with at least one other binder selected from the group consisting of fly ash, burnt shale, silica fume, zeolite, GGBF (ground granulated blast furnace) slag, limestone powder, hydraulic cement and non-hydraulic cement.

8. 8. The method of claim 7, wherein the slag is selected from the group consisting of steelmaking slag, stainless steelmaking slag, basic oxygen furnace sludge, blast furnace sludge, by-products of zinc, iron, copper production, and combinations thereof.

9. The method according to any one of claims 1 to 8, further comprising a reinforcing step of placing a reinforcing material in the gas-tight mold before the casting step.

10. The method of claim 9, wherein the reinforcing material is carbon steel, stainless steel and / or FRP reinforced rebar.

11. 11. The method according to any one of claims 1 to 10, wherein the cumulative calcium silicate content of the slag-based binder is at least 20% by weight.

12. The method according to any one of claims 1 to 11, wherein the preconditioning step is carried out to increase the porosity of the preconditioned slag-based intermediate body by at least 1% of its volume.

13. 13. The method of any one of claims 1 to 12, wherein the slag-based binder is a steelmaking slag selected from the group consisting of reduced steelmaking slag, oxidized steelmaking slag, converter steelmaking slag, electric arc furnace (EAF) slag, basic oxygen furnace (BOF) slag, ladle slag, fast-cooled steelmaking slag, and slow-cooled steelmaking slag, and combinations thereof.

14. 14. The method of any one of claims 1 to 13, wherein the wet-cast slag-based concrete product is selected from the group consisting of precast reinforced and non-reinforced concrete pipes, box culverts, drainage products, paving slabs, floor slabs, traffic barriers, walls, manholes, retaining walls, paving, tiles and roofing materials.

15. 15. The method of any one of claims 1 to 14, wherein the non-zero slump concrete composition comprises a slag content of at least 5% by weight.

16. 16. The method of any one of claims 1 to 15, wherein the non-zero slump concrete composition further comprises at least one of an accelerator, a retarder, a viscosity modifier, an air entrainer, a foaming agent, an ASR (alkali silica reaction) inhibitor, a washout inhibitor, a rust inhibitor, a shrinkage reducing agent, a concrete crack reducing agent, a plasticizer, a superplasticizer, a sealant, a paint, a coating, a water reducer, a water repellent, an efflorescence control agent, a polymer powder, a polymer latex, and a workability retention agent.

17. 17. The method of any one of claims 1 to 16, wherein the non-zero slump concrete composition further comprises at least one of cellulose fibers, glass fibers, micro synthetic fibers, natural fibers, PP fibers, PVA fibers, and steel fibers.

18. A method according to any one of claims 1 to 17, wherein the curing step does not include an additional external heat source and / or energy source.

19. The carbon dioxide-containing gas has a concentration of at least 5% by volume of CO ２ The method according to any one of claims 1 to 18, wherein the gas contains

Images