Supplementary cementitious materials comprising chromite

Abstract

The present disclosure relates to supplementary cementitious materials (SCMs) comprising chromite. The present disclosure also relates to methods of forming the supplementary cementitious materials (SCMs) comprising chromite.

Description

[0001] Title: Supplementary Cementitious Materials comprising Chromite

[0002] FIELD OF THE INVENTION

[0003] The present disclosure relates to supplementary cementitious materials (SCMs) comprising chromite. The present disclosure also relates to methods of forming the supplementary cementitious materials (SCMs) comprising chromite.

[0004] BACKGROUND OF THE INVENTION

[0005] Air conditioning is a common method for cooling buildings. With increasing global temperatures, demand for air conditioning is expected to increase. However, a high energy input is required to power the air conditioning, which in turn reduces the carbon dioxide performance of buildings. There is therefore a need to improve the carbon dioxide performance of buildings. In particular, there is a need to improve the thermal performance of buildings to reduce air conditioning usage and consequently improve the carbon dioxide performance of buildings.

[0006] One way to cool a building is through using cement based materials. Cement based materials that are left exposed, or painted, inside a building absorb heat. This advantageously reduces the temperature of the building, whilst the temperature of the cement based materials only marginally increases. Owing to the temperature of the cement based materials only marginally increasing, the surface temperature of the cement based materials remains low. To remove the heat from the cement based materials, buildings are generally ventilated overnight with night air. Night air is generally cooler than daytime air. By ventilating the buildings overnight with night air, the heat from the cement based materials is removed and the cement based materials can then reabsorb heat during the next day.

[0007] To maximise the benefits of using cement based materials to cool a building, the following three characteristics of cement based materials need to be maximised: (1) a high specific heat capacity so that cement based materials have maximum heat absorption, (2) a high density (the heavier the cement based materials, the more heat that can be stored by volume), and (3) moderate thermal conductivity so thatthe rate in which heat flows in and out of the cement based materials is roughly in step with the daily heating and cooling cycle of the building.

[0008] By using cement based materials to cool a building, the carbon dioxide performance of buildings is improved because there is a reduced need for air conditioning.

[0009] Examples of cement based materials include concrete and / or masonry. Concrete traditionally comprises cement, aggregates and water. The cement in the concrete is the mineral glue that binds the different components in the concrete together. Some types of cement, such as Ordinary Portland cement, contain a material called “clinker”. Clinker is usually present at a high amount in the cement. For example, Ordinary Portland cement contains more than ninety percent by weight of clinker. The clinker production process requires grinding and calcining up to a temperature of 1450 °C a mixture of limestone, clays and other minor components. The mixture is then mixed with three to five percent by weight of gypsum to form cement. The predominant source of carbon dioxide emissions in the production of cement (and cement based materials generally) is the production of the clinker. For example, clinker production typically generates approximately 850 kg of carbon dioxide per ton of clinker produced. The high carbon dioxide emissions can be attributed to the combustion of fuel and the decomposition of limestone into calcium oxide and carbon dioxide during the production of the clinker.

[0010] In recent years, supplementary cementitious materials (SCMs) have been used in addition to or as a partial replacement of the clinker to reduce the carbon dioxide emissions associated with cement based materials. SCMs include materials such as ground granulated blast furnace slag, fly ash, glass powder, natural pozzolana, calcined clays, silica fume, pumice, opaline rock, metakaolin and burnt shale. The use of SCMs is advantageous from an environmental and energy conservation viewpoint. By partly replacing clinker with SCMs, the environmental impact of cement based materials is improved. This is because the carbon dioxide emissions associated with clinker production, and thus cement based material production, is reduced. SCMs can also be formed as byproducts in industrial processes, and the reuse of SCMs further improves the energy efficiency of the cement based materials. For at least these reasons, the carbon dioxide performance of a building is furtherimproved when a cementitious based material comprising SCMs is used in the building.

[0011] Further advantages associated with the use of SCMs in cement based materials include improved durability, reduced permeability and enhanced strength of cement based materials. For example, SCMs contribute to the properties of cement based materials through hydraulic or pozzolanic activity. As a further example, SCMs also affect the chemical and physical properties of cement based materials. SCMs improve the physical properties of cement based materials by reducing the water absorption and apparent porosity, thus increasing the durability of the cement based materials.

[0012] There is an increasing demand for SCMs and decreasing availability of some SCMs. There is therefore a need for finding new types and sources of SCMs.

[0013] There is a continued need for improved cement based materials, and therefore also SCMs, that improve the carbon dioxide performance of buildings. In particular, there is a continued need for SCMs that enhance thermal properties of buildings and, in turn, improve the carbon dioxide performance of buildings by increasing the cooling efficiency of the buildings.

[0014] SUMMARY OF THE INVENTION

[0015] The present disclosure relates to supplementary cementitious materials (SCMs) comprising chromite. The present disclosure also relates to methods of forming the supplementary cementitious materials (SCMs) comprising chromite.

[0016] Representative features of the present invention are set out in the following clauses, which stand alone or may be combined, in any combination, with one or more features disclosed in the text and / or figures of the specification.

[0017] The present invention is as set out in the following clauses:

[0018] 1. A supplementary cementitious material (SCM) comprising chromite.2. The supplementary cementitious material (SCM) of clause 1 , wherein the chromite is present at: from 0.01 to 25 weight percent; or, from 0.05 to 20 weight percent; or, from 0.1 to 15 weight percent of the total weight of the supplementary cementitious material (SCM).

[0019] 3. The supplementary cementitious material (SCM) of clause 1 or clause 2, wherein the supplementary cementitious material (SCM) is: ground granulated blast furnace slag; and / or, fly ash; and / or, burnt shale; and / or, glass powder; and / or, silica fume; and / or, natural pozzolana; and / or, calcined clays; and / or, pumice; and / or, opaline rock; and / or, metakaolin; and / or, olivine; and / or, carbonated olivine; and / or, a combination thereof.

[0020] 4. The supplementary cementitious material (SCM) of any one of clauses 1 to 3, wherein the supplementary cementitious material (SCM) comprises, or consists of, carbonated olivine.

[0021] 5. The supplementary cementitious material (SCM) of any one of clauses 1 to 3, wherein the supplementary cementitious material (SCM), comprises, or consists of, olivine and carbonated olivine.

[0022] 6. The supplementary cementitious material (SCM) of clause 5, wherein the olivine is present at: from 0.01 to 60 weight percent; or, from 0.05 to 55 weight percent; or, from 0.1 to 45 weight percent of the total weight of the supplementary cementitious material (SCM).

[0023] 7. The supplementary cementitious material (SCM) of clause 5 or clause 6, wherein the carbonated olivine is present at: from 1 to 99 weight percent; or, from 35 to 97 weight percent; or, from 40 to 95 weight percent of the total weight of the supplementary cementitious material (SCM).

[0024] 8. A method of preparing the supplementary cementitious material (SCM) of any one of clauses 1 to 7, the method comprising the steps of:

[0025] (a) providing a supplementary cementitious material (SCM),(b) providing a chromite, and

[0026] (c) combining the supplementary cementitious material and the chromite.

[0027] 9. The method of clause 8, wherein the supplementary cementitious material (SCM) comprises, or consists of, carbonated olivine.

[0028] 10. The method of clause 8, wherein the supplementary cementitious material (SCM) comprises, or consists of, olivine and carbonated olivine.

[0029] 11. The method of clause 10, wherein the olivine is present at: from 0.01 to 60 weight percent; or, from 0.05 to 55 weight percent; or, from 0.1 to 45 weight percent of the total weight of the supplementary cementitious material (SCM).

[0030] 12. The method of clause 10 or clause 11 , wherein the carbonated olivine is present at: from 1 to 99 weight percent; or, from 35 to 97 weight percent; or, from 40 to 95 weight percent of the total weight of the supplementary cementitious material (SCM).

[0031] 13. The method of any one of clauses 8 to 12, wherein the carbonated olivine is prepared by reacting olivine with carbon dioxide in the presence of water; optionally,

[0032] (a) wherein the olivine is reacted with the carbon dioxide in the presence of water at a pressure of from 10 to 300 bar; or, from 25 to 250 bar; or, from 50 to 200 bar; and / or,

[0033] (b) wherein the olivine is reacted with the carbon dioxide in the presence of water at a temperature of from 100 to 350 °C; or, from 125 to 325 °C; or, from 150 to 300 °C; and / or,

[0034] (c) wherein the olivine is reacted with the carbon dioxide in the presence of water at a pressure of from 50 to 200 bar and a temperature of 150 to 300 °C.

[0035] 14. A composite cement comprising the supplementary cementitious material (SCM) of any one of clauses 1 to 7.15. The composite cement of clause 14, wherein the composite cement comprises: the supplementary cementitious material (SCM) at: from 1 to 95 weight percent; or, from 3 to 75 weight percent; or, from 10 to 60 weight percent of the total weight of the composite cement.

[0036] 16. The composite cement of clause 14 or clause 15, wherein the composite cement comprises:

[0037] cement at: from 1 to 95 weight percent; or, from 30 to 90 weight percent; or, from 40 to 85 weight percent of the total weight of the composite cement.

[0038] 17. A cement based material comprising the composite cement of any one of clauses 14 to 16, wherein the cement based material further comprises:

[0039] an aggregate, and

[0040] water.

[0041] 18. The cement based material of clause 17, wherein the cement based material comprises:

[0042] the composite cement and water at a ratio of: from 0.1 :0.1 to 1:1; or, from 0.25:0.50 to 0.50:0.85; or, 0.35:0.65 of water to composite cement by weight; and the composite cement and aggregate at a ratio of: from 2:1 to 10:1 ; or, 3:1 to 6:1 of aggregate to composite cement by weight;

[0043] wherein any remainder is unavoidable impurities.

[0044] 19. Use of the supplementary cementitious material (SCM) of any one of clauses 1 to 7 for improving carbon dioxide performance of buildings.

[0045] The present invention is also as set out in the following clauses:

[0046] 1A. A supplementary cementitious material (SCM) comprising chromite.

[0047] 2A. The supplementary cementitious material (SCM) of clause 1 A, wherein the chromite is present at: from 0.01 to 50 weight percent; or, from 0.01 to 25 weight percent; or, from 0.05 to 20 weight percent; or, from 0.1 to 15 weight percent of the total weight of the supplementary cementitious material (SCM).3A. The supplementary cementitious material (SCM) of clause 1 A or clause 2A, wherein the supplementary cementitious material (SCM) is: ground granulated blast furnace slag; and / or, fly ash; and / or, burnt shale; and / or, glass powder; and / or, silica fume; and / or, natural pozzolana; and / or, calcined clays; and / or, pumice; and / or, opaline rock; and / or, metakaolin; and / or, olivine; and / or, carbonated olivine; and / or, a combination thereof; optionally, wherein the supplementary cementitious material (SCM) is a material with pozzolanic properties, wherein the material with pozzolanic properties is: ground granulated blast furnace slag; and / or, fly ash; and / or, burnt shale; and / or, glass powder; and / or, silica fume; and / or, natural pozzolana; and / or, calcined clays; and / or, pumice; and / or, opaline rock; and / or, metakaolin; and / or, carbonated olivine; and / or, a combination thereof.

[0048] 4A. The supplementary cementitious material (SCM) of any one of clauses 1 A to 3A, wherein the supplementary cementitious material (SCM) comprises, or consists of, carbonated olivine; optionally, wherein the carbonated olivine has a carbonation degree of: from 10 to 100 weight percent; or, from 40 to 99 weight percent; or, from 60 to 95 weight percent; or, from 75 to 90 weight percent of the total weight of the carbonated olivine based on the total amount of carbon dioxide released during thermal decomposition of the carbonated olivine as determined by thermogravimetric analysis (TGA).

[0049] 5A. The supplementary cementitious material (SCM) of any one of clauses 1 A to 3A, wherein the supplementary cementitious material (SCM), comprises, or consists of, olivine and carbonated olivine.

[0050] 6A. The supplementary cementitious material (SCM) of clause 5A, wherein the olivine is present at: from 0.01 to 60 weight percent; or, from 0.05 to 55 weight percent; or, from 0.1 to 45 weight percent of the total weight of the supplementary cementitious material (SCM); and / or,

[0051] wherein the carbonated olivine is present at: from 1 to 99 weight percent; or, from 35 to 97 weight percent; or, from 40 to 95 weight percent of the total weight of the supplementary cementitious material (SCM).7A. The supplementary cementitious material (SCM) of any one of clauses 1 A to 4A, wherein the supplementary cementitious material (SCM) comprises:

[0052] from 0.1 to 50 weight percent of the total weight of the supplementary cementitious material (SCM) is chromite; and

[0053] from 50 to 99.9 weight percent of the total weight of the supplementary cementitious material (SCM) is carbonated olivine, wherein the carbonated olivine has a carbonation degree of 10 weight percent or greater of the total weight of the carbonated olivine.

[0054] 8A. A method of preparing the supplementary cementitious material (SCM) of any one of clauses 1 A to 7A, the method comprising the steps of:

[0055] (a) providing a supplementary cementitious material (SCM),

[0056] (b) providing a chromite, and

[0057] (c) combining the supplementary cementitious material and the chromite.

[0058] 9A. The method of clause 8A, wherein the supplementary cementitious material (SCM) comprises, or consists of, carbonated olivine; optionally, wherein the supplementary cementitious material (SCM) is a material with pozzolanic properties, wherein the material with pozzolanic properties comprises, or consists of, carbonated olivine.

[0059] 10A. The method of clause 8A, wherein the supplementary cementitious material (SCM) comprises, or consists of, olivine and carbonated olivine; optionally,

[0060] wherein the supplementary cementitious material (SCM) is a material with pozzolanic properties, wherein the material with pozzolanic properties comprises, or consists of, olivine and carbonated olivine; optionally,

[0061] wherein the olivine is present at: from 0.01 to 60 weight percent; or, from 0.05 to 55 weight percent; or, from 0.1 to 45 weight percent of the total weight of the supplementary cementitious material (SCM); and / or,wherein the carbonated olivine is present at: from 1 to 99 weight percent; or, from 35 to 97 weight percent; or, from 40 to 95 weight percent of the total weight of the supplementary cementitious material (SCM).

[0062] 11A. The method of any one of clauses 8A to 10A, wherein the carbonated olivine is prepared by reacting olivine with carbon dioxide in the presence of water; optionally,

[0063] (a) wherein the olivine is reacted with the carbon dioxide in the presence of water at a pressure of from 10 to 300 bar; or, from 25 to 250 bar; or, from 50 to 200 bar; and / or,

[0064] (b) wherein the olivine is reacted with the carbon dioxide in the presence of water at a temperature of from 100 to 350 °C; or, from 125 to 325 °C; or, from 150 to 300 °C; or, from 100 to 300 °C; or, from 100 to 250 °C; and / or,

[0065] (c) wherein the olivine is reacted with the carbon dioxide in the presence of water at a pressure of from 50 to 200 bar and a temperature of 150 to 300 °C.

[0066] 12A. A composite cement comprising the supplementary cementitious material (SCM) of any one of clauses 1 A to 7A.

[0067] 13A. The composite cement of clause 12A, wherein the composite cement comprises:

[0068] the supplementary cementitious material (SCM) at: from 1 to 95 weight percent; or, from 3 to 75 weight percent; or, from 10 to 60 weight percent of the total weight of the composite cement; and / or,

[0069] wherein the composite cement comprises:

[0070] cement at: from 1 to 95 weight percent; or, from 30 to 90 weight percent; or, from 40 to 85 weight percent of the total weight of the composite cement.

[0071] 14A. A cement based material comprising the composite cement of clause 12A or clause 13A, wherein the cement based material further comprises:

[0072] an aggregate, andwater.

[0073] 15A. The cement based material of clause 14A, wherein the cement based material comprises:

[0074] the composite cement and water at a ratio of: from 0.1 :0.1 to 1:1; or, from 0.25:0.50 to 0.50:0.85; or, 0.35:0.65 of water to composite cement by weight; and the composite cement and aggregate at a ratio of: from 2:1 to 10:1 ; or, 3:1 to 6:1 of aggregate to composite cement by weight;

[0075] wherein any remainder is unavoidable impurities.

[0076] 16A. Use of the supplementary cementitious material (SCM) of any one of clauses 1 A to 7A for improving carbon dioxide performance of buildings.

[0077] 17A. Use of the supplementary cementitious material (SCM) of any one of clauses 1 A to 7A for enhancing the thermal conductivity and volumetric heat capacity of cement based materials when compared to cement based materials based on only Portland cement (CEM I).

[0078] DETAILED DESCRIPTION

[0079] Embodiments of the claims may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein.

[0080] Embodiments of the invention are described below with reference to the accompanying drawings. The accompanying drawings illustrate various embodiments of systems, methods, and embodiments of various other aspects of the disclosure. Any person with ordinary skills in the art will appreciate that the illustrated element boundaries (e.g., boxes, groups of boxes, or other shapes) in the figures represent one example of the boundaries. It may be that in some examples one element may be designed as multiple elements or that multiple elements may be designed as one element. In some examples, an element shown as an internal component of one element may be implemented as an external component in another and vice versa. Furthermore, elements may not be drawn to scale. Nonlimiting and non-exhaustive descriptions are described with reference to the followingdrawings. The components in the figures are not necessarily to scale, emphasis instead being placed upon illustrating principles.

[0081] Figure 1 illustrates a comparative analysis of the influence of chromite on the thermal conductivity of various cementitious based materials after curing periods of 28 days and 56 days.

[0082] Figure 2 presents the evolution of thermal conductivity as a function of chromite content in cement based materials, in which 35 weight percent of the total weight of the cement is replaced with supplementary cementitious material (SCM), the SCM itself incorporating varying proportions of chromite.

[0083] Figure 3 shows the effect of chromite content on the heat capacity of a composition containing a 35 weight percent SCM replacement of the total weight of the cement based materials, wherein the SCM includes different levels of chromite.

[0084] The words "comprising," "having," "containing," and "including," and other forms thereof, are intended to be equivalent in meaning and be open ended in that an item or items following any one of these words is not meant to be an exhaustive listing of such item or items or meant to be limited to only the listed item or items. It must also be noted that as used herein and in the appended claims, the singular forms "a," "an," and "the" include plural references unless the context clearly dictates otherwise. Although any systems and methods similar or equivalent to those described herein can be used in the practice or testing of embodiments of the present disclosure, the preferred systems and methods are now described.

[0085] Some of the terms used to describe the present invention are set out below:

[0086] “Carbonated olivine” refers to a mix of magnesium carbonate defined by the chemical formula MgCOsand amorphous silica defined by the chemical formula SiO2. For example, carbonated olivine is a material obtained from the carbonation of natural olivine, as defined in the following description. During the carbonation, part of the magnesium in the natural olivine reacts with carbon dioxide to form magnesium carbonate (MgCOs) and part of the silica from the crystal structure in the naturalolivine is released to form amorphous silica (SiC ). Carbonated olivine may contain residual unreacted olivine.

[0087] “Carbonation” refers to a wet process of introducing carbon dioxide, within a high-pressure reactor, to transform magnesium and silica present in natural olivine into magnesium carbonate (MgCO3) and amorphous silica (SiO2), wherein the combination of the magnesium carbonate and amorphous silica is carbonated olivine. When the carbonation reaction does not reach full conversion, the resulting material contains unreacted olivine.

[0088] “Carbonation degree” refers to the proportion of a starting material (natural olivine) that is converted into carbonate-containing phases during reaction with carbon dioxide (CO2). The carbonation degree of olivine feedstock is determined by thermogravimetric analysis (TGA) based on the mass loss recorded between approximately 450 °C and 900 °C with release of carbon dioxide (CO2). Owing to the magnitude of the mass loss being directly proportional to the quantity of carbonate formed, the mass loss provides a quantitative measure of the extent of carbonation. For example, a carbonated olivine having a carbonation degree of 90 weight percent indicates that approximately 90 weight percent of the carbonated product is composed of magnesium carbonate (MgCO3) and amorphous silica (SiO2) and the remaining fraction consists of unreacted or partially reacted constituents such as magnesium orthosilicate (Mg2SiO4) and iron oxide (FeO and / or Fe2O3).

[0089] “Cement based materials” refers to a material that comprises cement and water. Cement based materials can further comprise aggregates (such as sand, gravel, crushed rocks, lightweight aggregates and / or a combination thereof), admixtures (such as water reducing agents, plasticizers, air entering agents, retarders, setting accelerators, rheology modifiers and / or a combination thereof), additives (such as pigments, fibers, fillers, reinforcing elements, self-healing agents and / or a combination thereof) and / or a combination thereof. Examples of cement based materials include, but are not limited to, concrete, masonry, mortars, plasters and known construction chemical products such as screed and / or tile adhesives.“Chromite” refers to a chromium rich mineral that belongs to the spinel group.

[0090] Chromite is an iron dominant species that is represented by the chemical formula FeCr2O4. Chromite may additionally contain Mg2+and trace amounts of Ti4+, wherein Fe2+is present at a higher amount than Mg2+, and Cr3+is present at a higher amount than Fe3+. Chromite forms a complete solid solution series with other members of the spinel group, e.g., chromite forms chromite-hercynite series, chromite-spinel series, chromite-magnetite series and chromite-magnesiochromite series.

[0091] “Composite cement” refers to a material that comprises a supplementary cementitious material and cement. The cement may be Ordinary Portland Cement (also known as CEM I). The composite cement may be used in cement based materials such as, but not limited to, concrete, masonry, mortars and known construction chemical products such as screed and / or tile adhesives. The composite cement can may be mixed with aggregates (such as sand, gravel, crushed rocks, lightweight aggregates and / or a combination thereof), water, admixtures (such as water reducing agents, plasticizers, air entering agents, retarders, setting accelerators, rheology modifiers and / or a combination thereof), additives (such as pigments, fibers, fillers, reinforcing elements, self-healing agents and / or a combination thereof) and / or a combination thereof to form a cement based material.

[0092] “Masonry” refers to a material that is constructed from cement based materials such as, but not limited to, stone, brick, tiles or a combination thereof.

[0093] “Olivine” refers to a magnesium iron silicate and is defined by the chemical formula: (Mg.Fe)2SiO4. The ratio of magnesium to iron varies between the two endmembers of the solid solution states for olivine: forsterite (Mg-endmember: Mg2SiO4) and fayalite (Fe-endmember: Fe2SiO4). Other names for olivine include chrysolite, serpentine, dunite, forsterite, magnesium iron silicate, magnesium iron solid solution silicate, forsterite-fayalite solid solution, nesosilicate, orthosilicate, ultramafic, alkali earth silicate, and, magnesium silicate.

[0094] “Portland cement” refers to a finely ground hydraulic binder made exclusively from Portland cement clinker and a small, controlled amount of calcium sulfate (such as gypsum) added only to regulate the setting time. In its 100% pure form, it contains nofillers, supplementary cementitious materials, pigments, or chemical additives, consisting solely of the characteristic clinker minerals — tricalcium silicate (C3S), dicalcium silicate (C2S), tricalcium aluminate (C3A), and tetracalcium aluminoferrite (C4AF) — formed by heating a precise mixture of limestone and clay-derived materials to clinkering temperature.

[0095] “Pozzolanic activity” refers to how quickly a mineral, such as a silicate (such as any compound of silica) and / or alumina, reacts with calcium (Ca2+) or calcium hydroxide (Ca(0H)2) in the presence of water to form compounds having cementitious properties. The compounds having cementitious properties include, but are not limited to, calcium silicate hydrates, calcium aluminate hydrates and calcium silicate aluminate hydrates. Pozzolanic activity can be measured by any method known in the art, such as the “activity index test” or the “ Frattini test”.

[0096] “Supplementary cementitious materials” or “SCMs” refers to materials that partially replace clinker in cement. SCMs can have pozzolanic properties. Materials with pozzolanic properties are characterised by a content of reactive silica and / or alumina which form strength providing calcium silicate hydrates, calcium hydrates and / or calcium silicate aluminate hydrates when water is added. SCMs include both latent hydraulic and pozzolanic materials. However, unreactive or only slightly reactive materials, such as but not limited to limestone, are differentiated from SCMs. SCMs improve the durability and strength of the final product and reduce the permeability of the final product. Examples of SCMs include, but are not limited to, ground granulated blast furnace slag, fly ash, burnt shale, glass powder, silica fume, natural pozzolana, calcined clays, pumice, opaline rock, metakaolin, olivine and / or carbonated olivine.

[0097] Supplementary cementitious materials (SCMs) comprising chromite

[0098] In one example of the present disclosure, a SCM comprises chromite.

[0099] The chromite may be present at: from 0.01 to 50 weight percent; or, from 0.01 to 25 weight percent; or, from 0.05 to 20 weight percent; or, from 0.1 to 15 weight percentof the total weight of the SCM. Preferably, the chromite is present at from 0.1 to 15 weight percent of the total weight of the SCM.

[0100] The SCM may be: ground granulated blast furnace slag; and / or, fly ash; and / or, burnt shale; and / or, glass powder; and / or, silica fume; and / or, natural pozzolana; and / or, calcined clays; and / or, pumice; and / or, opaline rock; and / or, metakaolin; and / or, olivine; and / or, carbonated olivine; and / or, a combination thereof.

[0101] The SCM may be a material with pozzolanic properties. The material with pozzolanic properties may be: ground granulated blast furnace slag; and / or, fly ash; and / or, burnt shale; and / or, glass powder; and / or, silica fume; and / or, natural pozzolana; and / or, calcined clays; and / or, pumice; and / or, opaline rock; and / or, metakaolin; and / or, carbonated olivine; and / or, a combination thereof.

[0102] Preferably, the SCM is carbonated olivine. Alternatively, the SCM additionally comprises carbonated olivine.

[0103] Preferably, the carbonated olivine has a carbonation degree of: from 10 to 100 weight percent; or, from 10 to 100; or, from 40 to 99 weight percent; or, from 60 to 95 weight percent; or, from 75 to 90 weight percent of the total weight of the carbonated olivine based on the total amount of carbon dioxide released during thermal decomposition of the carbonated olivine as determined by thermogravimetric analysis (TGA).

[0104] Preferably, the SCM is carbonated olivine and the chromite is present at from 0.01 to 15 weight percent of the total weight of the SCM.

[0105] Preferably, the SCM is olivine and carbonated olivine. Preferably, the SCM is a mixture of olivine and carbonated olivine. When the SCM is olivine and carbonated olivine, or a mixture of olivine and carbonated olivine, the olivine may be present at: from 0.01 to 60 weight percent; or, from 0.05 to 55 weight percent; or, from 0.1 to 45 weight percent of the total weight of the SCM and the carbonated olivine may be present at: from 1 to 99 weight percent; or, from 35 to 97 weight percent; or, from 40 to 95 weight percent of the total weight of the SCM, wherein any remainder isunavoidable impurities. Preferably, the olivine is present at from 0.1 to 45 weight percent of the total weight of the SCM and the carbonated olivine is present at from 40 to 95 weight percent of the total weight of the SCM, wherein any remainder is unavoidable impurities.

[0106] Preferably, the SCM is olivine and carbonated olivine, or a mixture of olivine and carbonated olivine, and the olivine is present at from 0.1 to 45 weight percent of the total weight of the SCM, the carbonated olivine is present at from 40 to 95 weight percent of the total weight of the SCM and the chromite is present at from 0.01 to 15 weight percent of the total weight of the SCM, wherein any remainder is unavoidable impurities.

[0107] Preferably, the SCM is carbonated olivine and the carbonated olivine is present at from 50 to 99.9 weight percent of the total weight of the SCM and the chromite is present at from 0.1 to 50 weight percent of the total weight of the SCM and the carbonated olivine has a carbonation degree of 10 weight percent or greater of the total weight of the carbonated olivine.

[0108] Advantageously, a SCM comprising chromite can be used in cement based materials that have improved heat capacity, density and thermal conductivity compared to known cement based materials.

[0109] Method of making the supplementary cementitious material (SCM) carbonated olivine

[0110] In one example of the present disclosure, the SCM comprises, or consists of, carbonated olivine. The carbonated olivine is prepared by reacting olivine with carbon dioxide in the presence of water. The reaction can be represented with the following equation:

[0111] Mg2SiO4 + 2CO2 — 2MgCOs + SiO2

[0112] Preferably, the olivine is reacted with the carbon dioxide in the presence of water at a pressure of: from 10 to 300 bar; or, from 25 to 250 bar; or, from 50 to 200 bar.Preferably, the olivine is reacted with the carbon dioxide in the presence of water at a temperature of: from 100 to 350 °C; or, from 125 to 325 °C; or, from 150 to 300 °C. Preferably, the olivine is reacted with the carbon dioxide in the presence of water at a temperature of: from 100 to 350 °C; or, from 100 to 300 °C; or, from 100 to 250 °C.

[0113] Preferably, the olivine is reacted with the carbon dioxide in the presence of water at a pressure of from 50 to 200 bar and a temperature of from 150 to 300 °C.

[0114] Preferably, the olivine is reacted with the carbon dioxide in the presence of water at a pressure of from 50 to 200 bar and a temperature of from 100 to 250 °C.

[0115] Preferably, the olivine carbonation has a carbonation degree of carbonated olivine of: from 10 to 100; or, from 40 to 99 weight percent; or, from 60 to 95 weight percent; or from 75 to 90 weight percent of the total weight of the carbonated olivine based on the total amount of carbon dioxide released during thermal decomposition of the carbonated product as determined by thermogravimetric analysis (TGA).

[0116] Preferably, the olivine is crushed and milled into fine particles prior to the reaction with the carbon dioxide in the presence of water. Preferably, the olivine is milled to a particle size of: from 700 mesh (20 pm) to 50 mesh (300 pm); or, from 600 mesh (23 pm) to 100 mesh (150 pm); or, from 500 mesh (25 pm) to 170 mesh (90 pm).

[0117] Preferably, the olivine is crushed to a particle size of from 500 mesh (25 pm) to 170 mesh (90 pm).

[0118] The olivine may be reacted with the carbon dioxide in the presence of water and a catalyst. The catalyst may be a chelating agent. The chelating agent may be: oxalic acid; and / or, citric acid; and / or, fulvic acid; and / or, ethylenediaminetetraacetic acid (EDTA); and / or, nitrilotriacetic acid (NTA); and / or, a combination thereof. Preferably, the chelating agent is oxalic acid.

[0119] The olivine may be reacted with the carbon dioxide in the presence of water and a salt. The salt may act as a catalyst. The salt may be: sodium bicarbonate; and / or, sodium carbonate; and / or, sodium chloride; and / or a combination thereof.In one example of the present disclosure, the SCM carbonated olivine is prepared by a method set out in the paper titled “Kinetics and mechanism of mineral carbonation of olivine for CO2 sequestration” by F. Wang et al., Minerals Engineering 131 (2019), 185-197, which is hereby incorporated by reference in its entirety.

[0120] Method of making supplementary cementitious materials (SCMs) comprising chromite

[0121] In one example of the present disclosure, the SCM is made by a method that comprises the following steps:

[0122] (a) providing a SCM,

[0123] (b) providing a chromite, and

[0124] (c) combining the SCM and the chromite.

[0125] In another example of the present disclosure, the SCM is made by a method that comprises the following steps:

[0126] (a) providing a SCM, wherein the SCM is a material with pozzolanic properties,

[0127] (b) providing a chromite, and

[0128] (c) combining the SCM and the chromite.

[0129] Preferably, wherein the material with pozzolanic properties comprises, or consists of, carbonated olivine; or, carbonated olivine and olivine; or, a mixture of carbonated olivine and olivine.

[0130] Composite cement comprising the supplementary cementitious materials (SCMs) comprising chromite

[0131] In one example of the present disclosure, composite cement comprises a SCM comprising chromite.

[0132] The chromite may be present in the SCM at: from 0.01 to 50 weight percent; or, from 0.01 to 25 weight percent; or, from 0.05 to 20 weight percent; or, from 0.1 to 15weight percent of the total weight of the SCM. Preferably, the chromite is present in the SCM at from 0.1 to 15 weight percent of the total weight of the SCM.

[0133] The SCM may be: ground granulated blast furnace slag; and / or, fly ash; and / or, burnt shale; and / or, glass powder; and / or, silica fume; and / or, natural pozzolana; and / or, calcined clays; and / or, pumice; and / or, opaline rock; and / or, metakaolin; and / or, olivine; and / or, carbonated olivine; and / or, a combination thereof.

[0134] The SCM may be a material with pozzolanic properties. The material with pozzolanic properties may be: ground granulated blast furnace slag; and / or, fly ash; and / or, burnt shale; and / or, glass powder; and / or, silica fume; and / or, natural pozzolana; and / or, calcined clays; and / or, pumice; and / or, opaline rock; and / or, metakaolin; and / or, carbonated olivine; and / or, a combination thereof.

[0135] Preferably, the SCM is carbonated olivine. The carbonated olivine may have a carbonation degree of: from 10 to 100 weight percent; or, from 40 to 99 weight percent; or, from 60 to 95 weight percent; or, from 75 to 90 weight percent of the total weight of the carbonated olivine based on the total amount of carbon dioxide released during thermal decomposition of the carbonated olivine as determined by thermogravimetric analysis (TGA).

[0136] Preferably, the SCM is carbonated olivine and the chromite is present at from 0.01 to 15 weight percent of the total weight of the SCM (the remainder of the SCM being carbonated olivine and unavoidable impurities).

[0137] Preferably, the SCM is olivine and carbonated olivine, or a mixture of olivine and carbonated olivine. When the SCM is olivine and carbonated olivine, or a mixture of olivine and carbonated olivine, the olivine may be present at: from 0.01 to 60 weight percent; or, from 0.05 to 55 weight percent; or, from 0.1 to 45 weight percent of the total weight of the SCM and the carbonated olivine may be present at: from 1 to 99 weight percent; or, from 35 to 97 weight percent; or, from 40 to 95 weight percent of the total weight of the SCM, wherein any remainder is unavoidable impurities.

[0138] Preferably, the olivine is present at from 0.1 to 45 weight percent of the total weightof the SCM and the carbonated olivine is present at from 40 to 95 weight percent of the total weight of the SCM, wherein any remainder is unavoidable impurities.

[0139] Preferably, the SCM is olivine and carbonated olivine, or a mixture of olivine and carbonated olivine, and the olivine is present at from 0.1 to 45 weight percent of the total weight of the SCM, the carbonated olivine is present at from 40 to 95 weight percent of the total weight of the SCM and the chromite is present at from 0.01 to 15 weight percent of the total weight of the SCM, wherein any remainder is unavoidable impurities.

[0140] The composite cement may comprise the SCM at: from 1 to 95 weight percent; or, from 3 to 75 weight percent; or, from 10 to 60 weight percent of the total weight of the composite cement. Preferably, the composite cement comprises the SCM at from 10 to 60 weight percent of the total weight of the composite cement. The SCM includes chromite as set out above.

[0141] When the SCM is carbonated olivine, the composite cement may comprise the SCM (carbonated olivine) at from: 1 to 80 weight percent; or, from 5 to 70 weight percent; or, from 10 to 60 weight percent of the total weight of the composite cement.

[0142] Preferably, the composite cement comprises the SCM (carbonated olivine) at from 10 to 60 weight percent of the total weight of the composite cement. The SCM includes chromite as set out above.

[0143] When the SCM is carbonated olivine and olivine; or, a mixture of olivine and carbonated olivine, the composite cement may comprise the SCM at from: 1 to 80 weight percent; or, from 5 to 70 weight percent; or, from 10 to 60 weight percent of the total weight of the composite cement. Preferably, the composite cement comprises the SCM at from 10 to 60 weight percent of the total weight of the composite cement. The SCM includes chromite as set out above.

[0144] The composite cement may additionally comprise cement. The cement in the composite cement may be: Ordinary Portland cement; and / or, Portland pozzolana cement; and / or, rapid-hardening cement; and / or, quick-setting cement; and / or, low-heat cement; and / or, sulfate-resisting cement; and / or, blast furnace slag cement;and / or, high-alumina cement; and / or, white cement; and / or, coloured cement; and / or, air-entraining cement; and / or, expansive cement; and / or, hydrographic cement; and / or, Portland-limestone cement; and / or, a combination thereof. Preferably, the cement is Ordinary Portland cement.

[0145] The composite cement may comprise the cement at: from 1 to 95 weight percent; or, from 30 to 90 weight percent; or, from 40 to 85 weight percent of the total weight of the composite cement. Preferably, the composite cement comprises the cement at from 40 to 85 weight percent of the total weight of the composite cement.

[0146] Preferably, the composite cement comprises the SCM at from 10 to 60 weight percent of the total weight of the composite cement and cement at from 40 to 85 weight percent of the total weight of the composite cement, wherein the remainder is unavoidable impurities. The SCM includes chromite as set out above.

[0147] When the SCM is carbonated olivine, the composite cement preferably comprises the SCM at from 10 to 60 weight percent of the total weight of the composite cement and cement at from 40 to 85 weight percent of the total weight of the composite cement, wherein the remainder is unavoidable impurities. The SCM includes chromite as set out above.

[0148] When the SCM is carbonated olivine and olivine; or, a mixture of olivine and carbonated olivine, the composite cement preferably comprises the SCM at from: 10 to 60 weight percent of the total weight of the composite cement and cement at from 40 to 85 weight percent of the total weight of the composite cement, wherein the remainder is unavoidable impurities. The SCM includes chromite as set out above.

[0149] The composite cement may be mixed with aggregates and water to form a cement based material. Typically, the composite cement is mixed with water to form a cement paste and the cement paste is then mixed with aggregate(s) to generate a cement based material such as mortar and / or concrete.The aggregate may be: gravel; and / or, sand; and / or, slag; and / or, recycled concrete; and / or, crushed rock; and / or, ballast; and / or, lightweight aggregates; and / or, any combination thereof. Preferably, the aggregate is sand or gravel.

[0150] The cement based material may comprise the composite cement and aggregate at a ratio of: from 2:1 to 10:1 ; or, 3:1 to 6:1 of aggregate to composite cement by weight. Preferably, the cement based material comprises the composite cement and aggregate at a ratio of 3:1 to 6:1 of aggregate to composite cement by weight.

[0151] The cement based material may comprise the composite cement and water at a ratio of: from 0.1 :0.1 to 1:1; or, from 0.25:0.50 to 0.50:0.85; or, 0.35:0.65 of water to composite cement by weight. Preferably, the cement based material comprises the composite cement and water at a ratio of 0.35:0.65 of water to composite cement by weight.

[0152] Preferably, the cement based material comprises the composite cement and aggregate at a ratio of 3:1 to 6:1 of aggregate to composite cement by weight and composite cement and water at a ratio of 0.35:0.65 of water to composite cement by weight, wherein any remainder is unavoidable impurities. The composite cement comprises a SCM as set out above.

[0153] The cement based material may additionally comprise admixtures and / or additives. Preferably, the admixtures are: water reducing agents; and / or, plasticizers; and / or, air entering agents; and / or, retarders; and / or setting accelerators; and / or, rheology modifiers; and / or, a combination thereof. Preferably, the additives are: pigments; and / or, fibers; and / or, fillers; and / or, reinforcing elements; and / or, self-healing agents; and / or a combination thereof.

[0154] In one example of the present disclosure, the cement based material, mortar, comprises:

[0155] a composite cement that comprises SCM at from 10 to 60 weight percent of the total weight of the composite cement and cement at from 40 to 85 weight percent of the total weight of the composite cement,

[0156] an aggregate at a ratio of 3:1 of aggregate to composite cement by weight,water at a ratio of 0.35:0.65 of water to composite cement by weight, wherein any remainder is unavoidable impurities, and

[0157] wherein the SCM comprises chromite and wherein the SCM is carbonated olivine; or, wherein the SCM comprises carbonated olivine and chromite.

[0158] Preferably, the cement is Ordinary Portland cement and the aggregate is sand or gravel.

[0159] Preferably, the chromite is present at from 0.01 to 15 weight percent of the total weight of the SCM.

[0160] In one example of the present disclosure, the cement based material, mortar, comprises:

[0161] a composite cement that comprises SCM at from 10 to 60 weight percent of the total weight of the composite cement and cement at from 40 to 85 weight percent of the total weight of the composite cement,

[0162] an aggregate at a ratio of 3:1 of aggregate to composite cement by weight, water at a ratio of 0.35:0.65 of water to composite cement by weight, wherein any remainder is unavoidable impurities, and

[0163] wherein the SCM comprises chromite and wherein the SCM is olivine and carbonated olivine; or, wherein the SCM comprises a mixture of olivine, carbonated olivine and chromite.

[0164] Preferably, the cement is Ordinary Portland cement and the aggregate is sand or gravel.

[0165] Preferably, chromite is present at from 0.01 to 15 weight percent of the total weight of the SCM.

[0166] Preferably, the olivine is present at from 0.1 to 45 weight percent of the total weight of the SCM and the carbonated olivine is present at from 40 to 95 weight percent of the total weight of the SCM and any remainder is unavoidable impurities.In one example of the present disclosure, the cement based material, concrete, comprises:

[0167] a composite cement that comprises SCM at from 10 to 60 weight percent of the total weight of the composite cement and cement at from 40 to 85 weight percent of the total weight of the composite cement,

[0168] an aggregate at a ratio of 6:1 of aggregate to composite cement by weight, water at a ratio of 0.35:0.65 of water to composite cement by weight, wherein any remainder is unavoidable impurities, and

[0169] wherein the SCM comprises chromite and wherein the SCM is carbonated olivine; or, wherein the SCM comprises carbonated olivine and chromite.

[0170] Preferably, the cement is Ordinary Portland cement (CEM I) and the aggregate is sand.

[0171] Preferably, the chromite is present at from 0.01 to 15 weight percent of the total weight of the SCM.

[0172] In one example of the present disclosure, the cement based material, concrete, comprises:

[0173] a composite cement that comprises SCM at from 10 to 60 weight percent of the total weight of the composite cement and cement at from 40 to 85 weight percent of the total weight of the composite cement

[0174] an aggregate at a ratio of 6:1 of aggregate to composite cement by weight, water at a ratio of 0.35:0.65 of water to composite cement by weight, wherein any remainder is unavoidable impurities, and

[0175] wherein the SCM comprises chromite and wherein the SCM is olivine and carbonated olivine; or, wherein the SCM comprises a mixture of olivine, carbonated olivine and chromite.

[0176] Preferably, the cement is Ordinary Portland cement (CEM I) and the aggregate is sand.

[0177] Preferably, the chromite is present at from 0.01 to 15 weight percent of the total weight of the SCM.Preferably, the olivine is present at from 0.1 to 45 weight percent of the total weight of the SCM and the carbonated olivine is present at from 40 to 95 weight percent of the total weight of the SCM and any remainder is unavoidable impurities.

[0178] EXAMPLES

[0179] The following are non-limiting examples that discuss, with reference to tables and figures, the advantages of the present invention. The examples set forth herein are merely examples among other possible examples.

[0180] Example 1: Chemical composition of chromite

[0181] In this non-limiting example, the chemical composition of chromite was analysed using x-ray fluorescence (XRF, such as on an Axios, Malvern Panalytical). The results are shown in Table 1, with any remainder being unavoidable impurities or chemicals unable to be observed with the XRF analysis.

[0182] Table 1: Chemical composition of chromite.

[0183] Chemical Unit Value

[0184] Cr20s % m / m 44

[0185] AI2O3 % m / m 14

[0186] FeO % m / m 25

[0187] MgO % m / m 11

[0188] SiO2% m / m 4

[0189]

[0190] Example 2: Measuring thermal conductivity and heat capacity of chromite powder blended with carbonated olivine

[0191] In this non-limiting example, thermal conductivity and heat capacity was measured on five cementitious based materials, wherein the cementitious based materials were in paste form. The cementitious based materials comprised Portland cement partiallysubstituted with carbonated olivine (OC), chromite (CR), or a blend thereof. The compositions of the five cementitious based materials are set out in Table 2.

[0192] Table 2: The compositions of the five cementitious based materials, wherein wt% is weight percent of the total weight of the cementitious based material (as a paste).

[0193] 2.5 wt% OC 5 wt% OC Components Reference 5 wt% CR 5wt% OC

[0194] 2.5 wt% CR 5 wt% CR Portland cement

[0195] 200 190 190 190 180 (Cem I) (g)

[0196] Chromite

[0197] - 10 - 5 10 powder (g)

[0198] Carbonated

[0199] - - 10 5 10 olivine (g)

[0200] Water (g) 100 100 100 100 100

[0201]

[0202] Preparation

[0203] The starting material (olivine) had a magnesium oxide (MgO) content of 49.3 weight percent, a silica (SiC ) content of 41.6 weight percent and an iron oxide (FeO) content of 7.6 weight percent of the total weight of the starting material (olivine) measured by XRF analysis (Axios, Malvern Panalytical). The starting material (olivine) had an olivine content of 89.4 weight percent of the total weight of the starting material (olivine), as measured by XRD analysis (Bruker D2 Phaser instrument). The starting material (olivine) had a D50 of 7pm (measured by laser diffraction, Sympatec Helos).

[0204] The starting material (olivine) was subjected to a carbonated reaction in the presence of carbon dioxide. The carbonation reaction was undertaken via a wet process using a high-pressure reactor. The carbonation reaction was preformed using a carbon dioxide purity of 99.7 percent for four hours at 200 °C and 180 bar in the presence of sodium bicarbonate (NaHCOs).Analysis of the resulting carbonated product, carbonated olivine, indicated a carbonation degree of 90 weight percent of the total weight of the carbonated olivine. In particular, the 90 weight percent of the product consisted of magnesium carbonate (MgCO3) and silicon dioxide (SiO2). The remaining 10 weight percent of the resulting carbonated product comprised unreacted or partially reacted components, including magnesium silicate (Mg2SiO4) and minor metal oxide constituents such as ferric oxide (FeO).

[0205] The carbonation degree was calculated based on mass loss determined by Thermogravimetric analysis (TGA-Mettler Toledo TGA / DSC 3+) in the temperature range 450 °C to 900 °C. In this temperature range, magnesium carbonate in the solid carbonated product decomposes and carbon dioxide was released.

[0206] 2MgCOs + SiO2 -> 2MgO+ SiO2 + 2CO2

[0207] The release of carbon dioxide from the solid carbonated product resulted in a loss in mass of the solid material. The magnitude of the mass loss was directly proportional to the amount of carbonate formed, thereby providing a quantitative measure of the extent of carbonation.

[0208] The carbonated olivine had a magnesium carbonate (MgCOs) content of 60.0 weight percent and an amorphous silica (SiO2) content of 28.6 weight percent of the total weight of the carbonated olivine, measured by XRD analysis (Bruker D2 Phaser instrument). The remaining part of the carbonated olivine included unreacted materials.

[0209] Mineralogical measurements were performed with XRD analysis using Rietveld quantification method.

[0210] Chromite feedstock was milled and sieved to obtain a particle size below 100 pm. Both the carbonated olivine and chromite fractions exhibited a median particle size (D50) of approximately 20 pm.Mixing and cement based material (as a paste) production

[0211] Prior to preparation of the cement based material in a paste, the carbonated olivine and chromite were homogenized to ensure uniform distribution. The cement based material in paste form was formulated using a water-to-cement based material ratio (w / c) of 0:5. The cement based material pastes were cast into cylindrical moulds with a diameter of 6 cm, demoulded after 24 hours, and subsequently cured in a moist environment until the designated testing age.

[0212] Cement based material (as a paste) conditioning

[0213] Before characterisation, all cement based materials (as pastes) were dried to a constant mass to eliminate moisture variability. Surfaces intended for contact with the thermal sensor were mechanically cleaned to remove loose particulates and to ensure consistent thermal interface conditions.

[0214] Thermal Property Measurement

[0215] Thermal conductivity and heat capacity measurements were performed using a C-Therm Trident analyser equipped with a Flex TPS module, employing the Transient Plane Source (TPS) method. The sensor was positioned between two geometrically identical cement based material pastes in a “sandwich” configuration to promote symmetric and uniform heat flow during testing.

[0216] A low-power heating pulse was applied to the sensor, which serves simultaneously as a heat source and a resistance-based temperature probe, consistent with the TPS operating principle in which the sensor’s resistance change is monitored to determine its transient temperature rise.The resulting temperature-time response was fitted using the TPS analytical model to obtain the material’s thermal conductivity (k) and thermal diffusivity (a). Volumetric Heat Capacity (p C) was then calculated according to:

[0217]

[0218] All measurements were conducted under ambient laboratory conditions.

[0219] For each cement based materials (as pastes), three independent measurements were conducted. The cement based materials (as pastes) were rotated between replicates to minimise contact bias.

[0220] Results: (1) Thermal conductivity measurements

[0221] The results of the thermal conductivity measurements of the cement based materials (as pastes) are shown in Figure 1.

[0222] Experimental evaluation of the cement based materials incorporating chromite and carbonated olivine (as a paste) demonstrated a clear, quantifiable, and controllable influence on thermal conductivity as a function of chromite content. As illustrated in Figure 1 , at 28 days, chromite provided a strong increase contribution of approximately +0.018 W / m K per 1 weight percent of chromite, whereas carbonated olivine imparted a modest negative effect of approximately -0.010 W / m K per 1 weight percent of carbonated olivine.

[0223] At 56 days, the influence of chromite increased to approximately +0.022 W / m K per 1 weight percent of chromite, while the effect of carbonated olivine became neutral, indicating age-dependent stabilization of the microstructure of the cement based material (as a paste). Cement based materials (as a paste) containing a blend of carbonated olivine and chromite (2.5 weight percent carbonated olivine +2.5 weight percent chromite, and 5 weight percent carbonated olivine +5 weight percent chromite) closely followed the linear superposition of the single-additive trends within±0.01 W / m K, confirming predictable, additive behaviour and the absence of adverse synergistic interactions across the tested cement based materials (as a paste).

[0224] The results established a reliable method for dose-responsive tuning of thermal conductivity in the matrices of cement based materials. Cement based materials (as a paste) containing 5-10 weight percent chromite achieved approximately 6-13% higher thermal conductivity at both 28 and 56 days relative to unmodified cement based materials (as pastes), with the final value adjustable through the chromite: carbonated olivine ratio. This controllable relationship enabled targeted design of cement-based materials, providing valuable design freedom for thermally functional construction elements and infrastructure applications requiring faster heat transfer and temperature equalization.

[0225] Results: (2) Volumetric Heat Capacity (p-C)

[0226] The results for volumetric heat capacity measurements are shown in Table 3.

[0227] As shown in Table 3, experimental testing of cementitious based materials (as a paste) incorporating a carbonated olivine and chromite demonstrated that chromite inclusion provides a pronounced increase in heat storage capacity (volumetric heat capacity) compared with both the reference cement based material (as a paste) and the cement based material (as a paste) containing only carbonated olivine as an SCM.

[0228] Table 3: Percentual increase of volumetric heat capacity of different compositions of cement based materials (as a paste) compared to the reference sample, wherein wt% is weight percent of the total weight of the cement based material (as a paste), CR is chromite and OC is carbonated olivine.

[0229] Composition % Increase vs Reference Reference —

[0230] 2.5 wt% CR + 2.5 wt% OC +0.08

[0231] 5 wt% CR + 5 wt% OC +0.18

[0232] 5 wt% OC +0.28

[0233]

[0234] 5 wt% CR +0.31

[0235]

[0236] At 28 days, the reference paste exhibited a volumetric heat capacity of approximately 2.44 MJ / m3K, while substitution with 5 weight percent carbonated olivine increased the volumetric heat capacity to 2.72 MJ / m3K. Under the same replacement level, 5 weight percent of chromite further elevated the volumetric heat capacity to 2.75 MJ / m3K, representing the highest enhancement among all evaluated mixtures and confirming chromite’s superior contribution to thermal mass.

[0237] Cement based materials (as pastes) containing both chromite and carbonated olivine (e.g., 2.5 weight percent carbonated olivine + 2.5 weight percent chromite, and 5 weight percent carbonated olivine + 5 weight percent chromite) yielded intermediate values in the range of 2.52-2.62 MJ / m3K, consistently reflecting the proportional influence of the chromite fraction. These results demonstrated that chromite, rather than carbonated olivine, was the dominant factor controlling heat-capacity gains within blended SCM systems. Without being bound by theory, this improvement can be attributed to chromite’s high density, favourable intrinsic material heat capacity, and its tendency to promote a denser, lower-porosity microstructure, thereby increasing the composite’s ability to store thermal energy per unit volume.

[0238] Accordingly, chromite acts as a functional amplifier of the SCM, enabling heat storage capacities beyond those achievable with carbonated olivine alone. This behaviour positions chromite-containing SCMs as advantageous for cementitious based materials designed for thermal buffering, thermal-energy storage, and temperature-regulation applications, where elevated thermal mass, predictable performance, and stable early-age behaviour are critical. The ability to enhance volumetric heat capacity through controlled chromite addition provides a valuable design parameter for engineering thermally functional construction materials.

[0239] Example 3: Measuring thermal conductivity and heat capacity of cement based materials, wherein the cement based materials comprise 35 weight percent SCM composed of carbonated olivine and chromite.In this non-limiting example, thermal conductivity and volumetric heat capacity tests were performed on three cement based materials (as pastes) comprising Portland cement and in which 35 weight percent of the Portland cement was replaced with blends of carbonated olivine (OC) and chromite (CR). The composition of the three cement based materials (as pastes) is set out in Table 4.

[0240] Table 4. The compositions of the three cementitious based materials, wherein wt% is weight percent of the total weight of the cementitious based material (as a paste).

[0241] Components 35 wt% OC 35 wt% OC 35 wt% OC (wt%) 5 wt% CR 10 wt% CR 20 wt% CR Portland cement

[0242] 65 65 65

[0243] (Cem I)

[0244] Chromite powder 5 10 20 Carbonated

[0245] 30 25 15

[0246] olivine

[0247]

[0248] Preparation

[0249] The carbonated olivine was produced as described in Example 2, obtaining 90 weight percent carbonation of the total weight of the carbonated olivine. The carbonated olivine had a magnesium carbonate (MgCOs) content of 60.0 weight percent and an amorphous silica (SiC ) content of 28.6 weight percent of the total weight of the carbonated olivine, measured by XRD analysis (Bruker D2 Phaser instrument). The remaining part of the carbonated olivine included unreacted materials such as silicate phases.

[0250] Chromite feedstock was milled and sieved to obtain a particle size below 100 pm. Both the carbonated olivine and chromite fractions exhibited a median particle size (D50) of approximately 20 pm.

[0251] The mixing and cement paste production, sample conditioning and thermal property measurement were performed as in Example 2.Results: (1) Thermal conductivity measurement

[0252] The results of the thermal conductivity measurements of the cement based materials (as a paste) are shown in Figure 2.

[0253] As can be seen in Figure 2, cementitious based materials (as pastes) in which 35 weight percent of the cement is replaced by an SCM blend containing chromite exhibited a clear, monotonic, and dose-responsive increase in thermal conductivity as the chromite fraction within the SCM is increased from 5 weight percent to 20 weight percent (measured at 21 days). Across this substitution window, thermal conductivity increased by approximately 4-6%, corresponding to absolute gains of +0.03 to +0.04 W / m K. When expressed as incremental material coefficients, chromite contributed approximately +0.002 to +0.0027 W / m K per 1% chromite within the SCM, or +0.004 to +0.007W / m K per 1% chromite when normalised to total binder mass. These values demonstrated that chromite effectively enhanced solid-state heat-transfer pathways, consistent with chromite’s inherently high thermal conductivity relative to hydrated cementitious phases.

[0254] Results: (2) Volumetric Heat Capacity (p-C)

[0255] The same compositions also showed a proportional increase in volumetric heat capacity, with measured improvements in volumetric heat capacity of approximately 2-4%, equivalent to +0.06 to +0.08 MJ / m3K relative to the cement based material containing 25 weight percent carbonated olivine and 5 weight percent chromite, as shown in Figure 3. On a per-increment basis, these enhancements correspond to approximately +0.004 to +0.005 MJ / m3K per 1% chromite within the SCM, or +0.01 to +0.015 MJ / m3K per 1% chromite relative to the total binder mass. The improvement is attributed to chromite’s high-density, high-heat-capacity mineral composition, which increased both the mass and the specific heat contribution of the solid phase, thereby elevating the composite’s heat-storage capacity per unit volume.Therefore, the results show that at a fixed 35 weight percent cement replacement level, adjusting the chromite fraction within the SCM provides a single-variable control mechanism for tuning both heat-storage capacity and thermal conductivity. This dual enhancement increases the thermal diffusivity of the composite — enabling faster heat equilibration — while simultaneously raising overall thermal mass, enabling the material to store more energy per unit volume. The combined effect yields cementitious materials with improved thermophysical responsiveness and stability, making chromite-containing SCMs particularly advantageous for thermal buffering, thermal-energy-storage, and temperature-regulation applications in concrete construction.

[0256] The features disclosed in the foregoing description, or the following claims, or the accompanying drawings, expressed in their specific forms or in terms of a means for performing the disclosed function, or a method or process for attaining the disclosed result, as appropriate, may, separately, or in any combination of such features, be utilized for realizing the invention in diverse forms thereof.

[0257] Although certain example aspects of the invention have been described, the scope of the appended claims is not intended to be limited solely to these examples. The claims are to be construed literally, purposively, and / or to encompass equivalents

Claims

CLAIMS1. A supplementary cementitious material (SCM) comprising chromite.

2. The supplementary cementitious material (SCM) of claim 1 , wherein the chromite is present at: from 0.01 to 50 weight percent; or, from 0.01 to 25 weight percent; or, from 0.05 to 20 weight percent; or, from 0.1 to 15 weight percent of the total weight of the supplementary cementitious material (SCM).

3. The supplementary cementitious material (SCM) of claim 1 or claim 2, wherein the supplementary cementitious material (SCM) is: ground granulated blast furnace slag; and / or, fly ash; and / or, burnt shale; and / or, glass powder; and / or, silica fume; and / or, natural pozzolana; and / or, calcined clays; and / or, pumice; and / or, opaline rock; and / or, metakaolin; and / or, olivine; and / or, carbonated olivine; and / or, a combination thereof; optionally, wherein the supplementary cementitious material (SCM) is a material with pozzolanic properties, wherein the material with pozzolanic properties is: ground granulated blast furnace slag; and / or, fly ash; and / or, burnt shale; and / or, glass powder; and / or, silica fume; and / or, natural pozzolana; and / or, calcined clays; and / or, pumice; and / or, opaline rock; and / or, metakaolin; and / or, carbonated olivine; and / or, a combination thereof.

4. The supplementary cementitious material (SCM) of any one of claims 1 to 3, wherein the supplementary cementitious material (SCM) comprises, or consists of, carbonated olivine; optionally, wherein the carbonated olivine has a carbonation degree of: from 10 to 100 weight percent; or, from 40 to 99 weight percent; or, from 60 to 95 weight percent; or, from 75 to 90 weight percent of the total weight of the carbonated olivine based on the total amount of carbon dioxide released during thermal decomposition of the carbonated olivine as determined by thermogravimetric analysis (TGA).

5. The supplementary cementitious material (SCM) of any one of claims 1 to 3, wherein the supplementary cementitious material (SCM), comprises, or consists of, olivine and carbonated olivine.

356. The supplementary cementitious material (SCM) of claim 5, wherein the olivine is present at: from 0.01 to 60 weight percent; or, from 0.05 to 55 weight percent; or, from 0.1 to 45 weight percent of the total weight of the supplementary cementitious material (SCM); and / or,wherein the carbonated olivine is present at: from 1 to 99 weight percent; or, from 35 to 97 weight percent; or, from 40 to 95 weight percent of the total weight of the supplementary cementitious material (SCM).

7. The supplementary cementitious material (SCM) of any one of claims 1 to 4, wherein the supplementary cementitious material (SCM) comprises:from 0.1 to 50 weight percent of the total weight of the supplementary cementitious material (SCM) is chromite; andfrom 50 to 99.9 weight percent of the total weight of the supplementary cementitious material (SCM) is carbonated olivine, wherein the carbonated olivine has a carbonation degree of 10 weight percent or greater of the total weight of the carbonated olivine.

8. A method of preparing the supplementary cementitious material (SCM) of any one of claims 1 to 7, the method comprising the steps of:(a) providing a supplementary cementitious material (SCM),(b) providing a chromite, and(c) combining the supplementary cementitious material and the chromite.

9. The method of claim 8, wherein the supplementary cementitious material (SCM) comprises, or consists of, carbonated olivine; optionally, wherein the supplementary cementitious material (SCM) is a material with pozzolanic properties, wherein the material with pozzolanic properties comprises, or consists of, carbonated olivine.

10. The method of claim 8, wherein the supplementary cementitious material (SCM) comprises, or consists of, olivine and carbonated olivine; optionally,36wherein the supplementary cementitious material (SCM) is a material with pozzolanic properties, wherein the material with pozzolanic properties comprises, or consists of, olivine and carbonated olivine; optionally,wherein the olivine is present at: from 0.01 to 60 weight percent; or, from 0.05 to 55 weight percent; or, from 0.1 to 45 weight percent of the total weight of the supplementary cementitious material (SCM); and / or,wherein the carbonated olivine is present at: from 1 to 99 weight percent; or, from 35 to 97 weight percent; or, from 40 to 95 weight percent of the total weight of the supplementary cementitious material (SCM).

11. The method of any one of claims 8 to 10, wherein the carbonated olivine is prepared by reacting olivine with carbon dioxide in the presence of water; optionally,(a) wherein the olivine is reacted with the carbon dioxide in the presence of water at a pressure of from 10 to 300 bar; or, from 25 to 250 bar; or, from 50 to 200 bar; and / or,(b) wherein the olivine is reacted with the carbon dioxide in the presence of water at a temperature of from 100 to 350 °C; or, from 125 to 325 °C; or, from 150 to 300 °C; or, from 100 to 300 °C; or, from 100 to 250 °C; and / or,(c) wherein the olivine is reacted with the carbon dioxide in the presence of water at a pressure of from 50 to 200 bar and a temperature of 150 to 300 °C.

12. A composite cement comprising the supplementary cementitious material (SCM) of any one of claims 1 to 7.

13. The composite cement of claim 12, wherein the composite cement comprises: the supplementary cementitious material (SCM) at: from 1 to 95 weight percent; or, from 3 to 75 weight percent; or, from 10 to 60 weight percent of the total weight of the composite cement; and / or,wherein the composite cement comprises:cement at: from 1 to 95 weight percent; or, from 30 to 90 weight percent; or, from 40 to 85 weight percent of the total weight of the composite cement.

14. A cement based material comprising the composite cement of claim 12 or claim 13, wherein the cement based material further comprises:an aggregate, andwater.

15. The cement based material of claim 14, wherein the cement based material comprises:the composite cement and water at a ratio of: from 0.1 :0.1 to 1:1; or, from 0.25:0.50 to 0.50:0.85; or, 0.35:0.65 of water to composite cement by weight; and the composite cement and aggregate at a ratio of: from 2:1 to 10:1 ; or, 3:1 to 6:1 of aggregate to composite cement by weight;wherein any remainder is unavoidable impurities.

16. Use of the supplementary cementitious material (SCM) of any one of claims 1 to 7 for improving carbon dioxide performance of buildings.

17. Use of the supplementary cementitious material (SCM) of any one of claims 1 to 7 for enhancing the thermal conductivity and volumetric heat capacity of cement based materials when compared to cement based materials based on only Portland cement (CEM I).

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