Aspects of the invention include a method of producing a cement material comprising step of: first reacting a calcium-bearing starting material with a first acid to produce an aqueous first calcium salt; second reacting the aqueous first calcium salt with a second acid to produce a solid second calcium salt; wherein the second acid is different from the first acid and the second calcium salt is different from the first calcium salt; and thermally treating the second calcium salt to produce a first cement material. Preferably, but not necessarily, during the second reacting step, reaction between the first calcium salt and the second acid regenerates the first acid.

Aspects of the invention include a method of producing a cement material comprising step of: first reacting a calcium-bearing starting material with a first acid to produce an aqueous first calcium salt; second reacting the aqueous first calcium salt with a second acid to produce a solid second calcium salt; wherein the second acid is different from the first acid and the second calcium salt is different from the first calcium salt; and thermally treating the second calcium salt to produce a first cement material. Preferably, but not necessarily, during the second reacting step, reaction between the first calcium salt and the second acid regenerates the first acid.

The present disclosure concerns an aluminosilicate having a Blaine fineness of about 500 m.sup.2/kg to about 3000 m.sup.2/kg and/or a specific surface area of about 4 m.sup.2/g to about 20 m.sup.2/g, as well as the uses thereof. The present disclosure also comprises a dry cementing composition and a mortar or concrete composition, the compositions comprising said aluminosilicate. The present disclosure also comprises a process for the manufacture of aluminosilicate. The process comprises: roasting a spodumene concentrate in an acid medium; leaching the acidic roast spodumene concentrate so as to obtain a mixture comprising a solid comprising the aluminosilicate and a leachate; and separating the aluminosilicate from the leachate in an acid medium, wherein said aluminosilicate contains a calcium concentration of less than about 5%.

The present disclosure concerns an aluminosilicate having a Blaine fineness of about 500 m.sup.2/kg to about 3000 m.sup.2/kg and/or a specific surface area of about 4 m.sup.2/g to about 20 m.sup.2/g, as well as the uses thereof. The present disclosure also comprises a dry cementing composition and a mortar or concrete composition, the compositions comprising said aluminosilicate. The present disclosure also comprises a process for the manufacture of aluminosilicate. The process comprises: roasting a spodumene concentrate in an acid medium; leaching the acidic roast spodumene concentrate so as to obtain a mixture comprising a solid comprising the aluminosilicate and a leachate; and separating the aluminosilicate from the leachate in an acid medium, wherein said aluminosilicate contains a calcium concentration of less than about 5%.

A method of producing a supplementary cementitious material, includes providing at least one waste material selected from quarry sludge, aggregate washing sludge and road cleaning sludge, removing excess water from said waste material so as to provide a dry waste material, and either: mixing the dry waste material with a source of calcium sulphate to obtain a raw material mixture, and calcining the raw material mixture at a temperature of 700-900 C. to obtain the supplementary cementitious material, or: calcining the dry waste material at a temperature of 700-900 C. to obtain a calcined waste material, and mixing the calcined waste material with a calcined source of calcium sulphate to obtain the supplementary cementitious material.

A method of producing a supplementary cementitious material, includes providing at least one waste material selected from quarry sludge, aggregate washing sludge and road cleaning sludge, removing excess water from said waste material so as to provide a dry waste material, and either: mixing the dry waste material with a source of calcium sulphate to obtain a raw material mixture, and calcining the raw material mixture at a temperature of 700-900 C. to obtain the supplementary cementitious material, or: calcining the dry waste material at a temperature of 700-900 C. to obtain a calcined waste material, and mixing the calcined waste material with a calcined source of calcium sulphate to obtain the supplementary cementitious material.

A shrinkage compensating concrete does not require restraint. The expansive forces developed during hydration compensate for concrete shrinkage, obviating the need for any added internal or external restraint element. Using this new shrinkage compensating concrete, substantially crack-free slabs may be built without using restraining steel bars, fibers, or other separate restraining element. The shrinkage compensating concrete includes a cement that develops internal expansive forces that never exceed the tensile strength of the concrete, such that the internal expansion compensates for the concrete shrinkage. The expansive cement may be an ASTMS, M or S cement, or other expansive cements may also be used.

A shrinkage compensating concrete does not require restraint. The expansive forces developed during hydration compensate for concrete shrinkage, obviating the need for any added internal or external restraint element. Using this new shrinkage compensating concrete, substantially crack-free slabs may be built without using restraining steel bars, fibers, or other separate restraining element. The shrinkage compensating concrete includes a cement that develops internal expansive forces that never exceed the tensile strength of the concrete, such that the internal expansion compensates for the concrete shrinkage. The expansive cement may be an ASTMS, M or S cement, or other expansive cements may also be used.

Aspects of the invention include a method of producing a cement material comprising step of: first reacting a calcium-bearing starting material with a first acid to produce an aqueous first calcium salt; second reacting the aqueous first calcium salt with a second acid to produce a solid second calcium salt; wherein the second acid is different from the first acid and the second calcium salt is different from the first calcium salt; and thermally treating the second calcium salt to produce a first cement material. Preferably, but not necessarily, during the second reacting step, reaction between the first calcium salt and the second acid regenerates the first acid.

Aspects of the invention include a method of producing a cement material comprising step of: first reacting a calcium-bearing starting material with a first acid to produce an aqueous first calcium salt; second reacting the aqueous first calcium salt with a second acid to produce a solid second calcium salt; wherein the second acid is different from the first acid and the second calcium salt is different from the first calcium salt; and thermally treating the second calcium salt to produce a first cement material. Preferably, but not necessarily, during the second reacting step, reaction between the first calcium salt and the second acid regenerates the first acid.