The present invention provides calcium sulphate-based product having reduced shrinkage after exposure to high temperatures, the product comprising gypsum, a pozzolan source e.g. in an amount between 4-27 wt %) and a metal salt additive in an amount between 0.5 and 10 wt %). The pozzolan source may be selected from a kaolinitic clay material, fly ash, rice husk ash, diatomaceous earths, volcanic ashes and pumices, micro-silica, silica fume and silicone oil, The metal salt additive may be a metal salt which decomposes between a temperature of 300-500° C. to yield a metal oxide, e.g. magnesium nitrate.

The present invention provides calcium sulphate-based product having reduced shrinkage after exposure to high temperatures, the product comprising gypsum, a pozzolan source e.g. in an amount between 4-27 wt %) and a metal salt additive in an amount between 0.5 and 10 wt %). The pozzolan source may be selected from a kaolinitic clay material, fly ash, rice husk ash, diatomaceous earths, volcanic ashes and pumices, micro-silica, silica fume and silicone oil, The metal salt additive may be a metal salt which decomposes between a temperature of 300-500° C. to yield a metal oxide, e.g. magnesium nitrate.

A two-component inorganic injection mortar system includes a curable aqueous-phase aluminous cement component A and an initiator component B in aqueous-phase for initiating the curing process. Component A includes at least one blocking agent which is phosphoric acid, metaphosphoric acid, phosphorous acid or phosphonic acid, at least one plasticizer and water. Component B includes an initiator, at least one retarder, at least one mineral filler and water. The curable aqueous-phase aluminous cement component A includes calcium aluminate cement having an average particle size in the range of from 0.5 to 15 μm. A two-component system, which is ready-for-use, can be used for chemical fastening of anchors, such as metal elements, or in mineral substrates, such as structures made of brickwork, concrete, pervious concrete or natural stone.

A two-component inorganic injection mortar system includes a curable aqueous-phase aluminous cement component A and an initiator component B in aqueous-phase for initiating the curing process. Component A includes at least one blocking agent which is phosphoric acid, metaphosphoric acid, phosphorous acid or phosphonic acid, at least one plasticizer and water. Component B includes an initiator, at least one retarder, at least one mineral filler and water. The curable aqueous-phase aluminous cement component A includes calcium aluminate cement having an average particle size in the range of from 0.5 to 15 μm. A two-component system, which is ready-for-use, can be used for chemical fastening of anchors, such as metal elements, or in mineral substrates, such as structures made of brickwork, concrete, pervious concrete or natural stone.

A cementitious composition with accelerated curing at low temperatures particularly at temperatures <5° C., especially at temperatures <0° C. The cementitious composition consists of 2 components with a first component A including at least one ordinary Portland cement, at least one cement selected from calcium aluminate cement and/or calcium sulfoaluminate cement, a powder P, selected from the group consisting of carbonates or hydrogen carbonates of alkali and/or alkaline earth metals, optionally aggregates, optionally other additives and a second component B comprising at least one accelerator, an anti-freeze agent, water, and optionally other additives. The composition shows increased development of compressive strength, maintain good workability, and have particularly low shrinkage, also when cured at temperatures <5° C., especially <0° C., and as low as −10° C.

A cementitious composition with accelerated curing at low temperatures particularly at temperatures <5° C., especially at temperatures <0° C. The cementitious composition consists of 2 components with a first component A including at least one ordinary Portland cement, at least one cement selected from calcium aluminate cement and/or calcium sulfoaluminate cement, a powder P, selected from the group consisting of carbonates or hydrogen carbonates of alkali and/or alkaline earth metals, optionally aggregates, optionally other additives and a second component B comprising at least one accelerator, an anti-freeze agent, water, and optionally other additives. The composition shows increased development of compressive strength, maintain good workability, and have particularly low shrinkage, also when cured at temperatures <5° C., especially <0° C., and as low as −10° C.

Method and composition for producing aggregates from cement and concrete, including residual or returned concrete. Exemplary methods involve the use of an aggregate-forming inducer that provides a surface anchoring site for cement paste to bond/adhere, such as shredded news print, cardboard, or mixtures thereof, and also including fiber materials such as polymers, glass, and other material fibers. The aggregate-forming inducer is mixed with fresh concrete until aggregates are formed.

Method and composition for producing aggregates from cement and concrete, including residual or returned concrete. Exemplary methods involve the use of an aggregate-forming inducer that provides a surface anchoring site for cement paste to bond/adhere, such as shredded news print, cardboard, or mixtures thereof, and also including fiber materials such as polymers, glass, and other material fibers. The aggregate-forming inducer is mixed with fresh concrete until aggregates are formed.

Provided is a concrete hardener composition. The concrete hardener composition includes a sodium silicate compound, an acid compound and a balance amount of solvent. The sodium silicate compound includes sodium silicate or a mixture of sodium silicate and sodium methylsilicate. The acid compound includes acetic acid, glycolic acid, ethylenediaminetetraacetic acid, tartaric acid, nitric acid, boric acid or a combination thereof. The solvent includes water or a mixed solution of water and polyol. Based on the total weight of the concrete hardener composition, the content of silicon is between 5 wt % and 15 wt %, and the content of the acid compound is between 2 wt % and 30 wt %.

Provided is a concrete hardener composition. The concrete hardener composition includes a sodium silicate compound, an acid compound and a balance amount of solvent. The sodium silicate compound includes sodium silicate or a mixture of sodium silicate and sodium methylsilicate. The acid compound includes acetic acid, glycolic acid, ethylenediaminetetraacetic acid, tartaric acid, nitric acid, boric acid or a combination thereof. The solvent includes water or a mixed solution of water and polyol. Based on the total weight of the concrete hardener composition, the content of silicon is between 5 wt % and 15 wt %, and the content of the acid compound is between 2 wt % and 30 wt %.