Calcium silicate-based cements and concretes are disclosed, which result in concrete compositions that have an increased durability. A cement product includes a plurality of particles of a carbonatable calcium silicate cement and a hydrophobic organic acid, or a salt thereof, or a silane, or a polysiloxane.

A cement composition is provided. The cement composition comprises: a microcapsule and cement. The microcapsule is provided with a core-shell structure having i) a core containing a water-repellent organosilicon material selected from the group consisting of organosilanes, organosilane partial condensation products, and branched siloxane resins, and ii) a shell of a silicon-based network polymer containing a silica unit. The microcapsule is included at 0.01 to less than 0.5 parts by weight per 100 parts by weight of the cement. Thus, it is possible to provide a cement composition that can provide a cured product having high strength, as well as excellent air content stability, substance penetration prevention, drying shrinkage, and freeze-thaw resistance.

A method for making a carbonated precast concrete product includes: obtaining a mixture including at least one binder material, an aggregate, and water; molding the mixture into a molded intermediate; demolding the molded intermediate to obtain a demolded intermediate, the demolded intermediate having a first water-to-binder ratio; conditioning the demolded intermediate to provide a conditioned article having a second water-to-binder ratio less than the first water-to-binder ratio of the demolded intermediate; moisturizing at least one surface of the conditioned article with an aqueous medium, thereby causing a weight gain of the conditioned article and providing a moisturized product, a first portion of the moisturized product having a third water-to-binder ratio greater than a fourth water-to-binder ratio of a remainder of the moisturized product; and curing the moisturized product with carbon dioxide to obtain the carbonated precast concrete product.

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 invention relates to a mineral binder suitable for use in binding aggregate in a mineral mortar or concrete mixture, said binder comprising the following components:

a) at least 40 wt % of calcined kaolinitic clay and ultrafine crushed CDW,
wherein the ratio between calcined clay and ultrafine crushed CDW is between 3:7 and 1:1 (w/w),
b) optionally 2-50 wt. % of a chemical activator; and
wherein the calcined kaolinitic clay, the ultrafine crushed CDW and the optionally present chemical activator are present in a combined amount of at least 90 wt. %, based on the total weight of the binder. The invention further relates to mineral mortar or concrete mixtures based on this mineral binder, as well as building units made from these mixtures.

A method for making a carbonated precast concrete product includes: obtaining a mixture including at least one binder material, an aggregate, and water; molding the mixture into a molded intermediate; demolding the molded intermediate to obtain a demolded intermediate, the demolded intermediate having a first water-to-binder ratio; conditioning the demolded intermediate to provide a conditioned article having a second water-to-binder ratio less than the first water-to-binder ratio of the demolded intermediate; moisturizing at least one surface of the conditioned article with an aqueous medium, thereby causing a weight gain of the conditioned article and providing a moisturized product, a first portion of the moisturized product having a third water-to-binder ratio greater than a fourth water-to-binder ratio of a remainder of the moisturized product; and curing the moisturized product with carbon dioxide to obtain the carbonated precast concrete product.

A precast concrete molded body is provided, which is a cured product of a concrete composition. The concrete composition comprises: a microcapsule; cement; and at least one type of aggregate. The microcapsule is provided with a core-shell structure having i) a core made of a water repellent organosilicon material selected from the group consisting of organosilanes, organosilane partial condensation products, and branched siloxane resins, and ii) a shell made of a silicon-based network polymer containing silica units. The concrete composition contains 0.01 to less than 0.5 parts by weight of microcapsules per 100 parts by weight of cement. Thereby, a precast concrete molded body can be provided, having high strength, as well as at least one of the following properties: air content stability, substance penetration prevention, and freeze-thaw resistance.

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 invention relates to use of nano-fibrillar cellulose as an gas-entrainment stabilizer, which when used in cementitious materials, provides improved gas pore structure quality and/or stability and/or robustness with regard to water content variation. The invention further relates to a method for stabilizing gasentrainment of cementitious materials and to a method for providing cementitious material with improved air pore structure quality and/or stability and/or robustness with regard to water content variation.

A method of expanding expandable polymeric microspheres including contacting an aqueous slurry including unexpanded, expandable polymeric microspheres with heat in-situ during manufacture of a cementitious composition or article, wherein the aqueous slurry optionally further includes an admixture therefor. A method of manufacturing a cementitious composition or article includes: (i) contacting an aqueous slurry of unexpanded, expandable polymeric microspheres with heat proximate to and/or during said manufacturing of the cementitious composition to create expanded polymeric microspheres; (ii) pre-wetting the expanded polymeric microspheres; and (iii) mixing the pre-wetted, expanded polymeric microspheres with cement and water to form the cementitious composition, wherein the aqueous slurry optionally further comprises an admixture therefor.