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.

The present invention corresponds to a cement formulation based on sulfoaluminate comprising a specific Ye'elimite crystal proportion having enhanced mechanical resistance, setting and low CO2 emission features. A concrete obtained when mixing said formulation with water and gypsum is further described, having a superior performance at initial ages compared to concrete obtained from Portland cement.

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.

Composition comprising a polyphosphate, an amine and an inorganic sulfate compound for enhancing the workability and/or the strength development of hydraulic binders comprising a cement and a high water demand supplementary cementitious material and/or a high water demand filler.

Composition comprising a polyphosphate, an amine and an inorganic sulfate compound for enhancing the workability and/or the strength development of hydraulic binders comprising a cement and a high water demand supplementary cementitious material and/or a high water demand filler.

The present disclosure provides a hydraulic phosphogypsum (PG)-based cementitious material, and a preparation method and use thereof, belonging to the technical field of cementitious materials. The present disclosure provides a hydraulic PG-based cementitious material, including the following raw materials: modified PG particles and an auxiliary active powder, where the modified PG particles have a dosage of 50 wt % to 95 wt %; the modified PG particles are obtained by conducting modification on original PG particles through a calcareous material, and the calcareous material has a mass 3% to 5% of that of the original PG particles; and the original PG particles have typical dimensions of: a length of 50 m to 200 m and an aspect ratio of 1.5 to 5; and at least 80% of materials in the auxiliary active powder have a particle size of less than or equal to 60 m. In the present disclosure, the hydraulic PG-based cementitious material adopts a particle accumulation method of gap grading. The modified PG particles have a dosage up to 95 wt %, and can form a hydraulic structure after hydration. Therefore, the cementitious material can be applied in various occasions.

The present invention relates to a rapid-setting hydraulic binder composition and, more specifically, to a hydraulic binder composition, which contains tricalcium aluminate (C3A) and dodecacalcium heptaaluminate (C12A7), and thus is rapidly set, has an easily adjustable setting time, and is bio-friendly.

The present invention relates to a rapid-setting hydraulic binder composition and, more specifically, to a hydraulic binder composition, which contains tricalcium aluminate (C3A) and dodecacalcium heptaaluminate (C12A7), and thus is rapidly set, has an easily adjustable setting time, and is bio-friendly.