Disclosed are a mixed shrinkage reducing agent for concrete and a preparation method thereof. The mixed shrinkage reducing agent for concrete includes the following components in parts by weight: 35-45 of alkali modified diatomite, 15-22 of magnesium oxide, 13-20 of vermiculite, 8-11 of borax, 3-9 of sodium hexametaphosphate, and 7-13 of citric acid modified starch. The mixed shrinkage reducing agent for concrete according to the present application is used as an admixture to be mixed into cement for preparing concrete.

Disclosed are a mixed shrinkage reducing agent for concrete and a preparation method thereof. The mixed shrinkage reducing agent for concrete includes the following components in parts by weight: 35-45 of alkali modified diatomite, 15-22 of magnesium oxide, 13-20 of vermiculite, 8-11 of borax, 3-9 of sodium hexametaphosphate, and 7-13 of citric acid modified starch. The mixed shrinkage reducing agent for concrete according to the present application is used as an admixture to be mixed into cement for preparing concrete.

Provided herein are methods and compositions for carbonation of recycled concrete aggregates (RCA) to produce carbonated RCA. In addition, uses of the carbonated RCA, such as in building materials, and building materials containing RCA, are included. Carbonation of RCA may be used alone or may be used in combination with other carbonation processes associated with concrete manufacture, such as carbonation of wet concrete mixes and/or carbonation of concrete wash water.

Provided herein are methods and compositions for carbonation of recycled concrete aggregates (RCA) to produce carbonated RCA. In addition, uses of the carbonated RCA, such as in building materials, and building materials containing RCA, are included. Carbonation of RCA may be used alone or may be used in combination with other carbonation processes associated with concrete manufacture, such as carbonation of wet concrete mixes and/or carbonation of concrete wash water.

The object of the present invention is a novel admixture comprising a hardening accelerator for hydraulic compositions based on Portland cement and other supplementary cementitious materials.

The object of the present invention is a novel admixture comprising a hardening accelerator for hydraulic compositions based on Portland cement and other supplementary cementitious materials.

Cementitious compositions have an oxidatively degraded polysaccharide as a water reducing agent to provide similar water reducing properties to cementitious composition formulated with lignosulfonates. The oxidatively degraded polysaccharides have the advantage over lignosulfonates of a lower price and a more consistent quality and are expected to be compatible with polycarboxylatether cement additives. Further, methods for the preparation of corresponding cementitious compositions, appropriate oxidatively degraded polysaccharides and methods for producing the same, as well as the use of oxidatively degraded polysaccharides as water reducing agents in cementitious compositions.

Cementitious compositions have an oxidatively degraded polysaccharide as a water reducing agent to provide similar water reducing properties to cementitious composition formulated with lignosulfonates. The oxidatively degraded polysaccharides have the advantage over lignosulfonates of a lower price and a more consistent quality and are expected to be compatible with polycarboxylatether cement additives. Further, methods for the preparation of corresponding cementitious compositions, appropriate oxidatively degraded polysaccharides and methods for producing the same, as well as the use of oxidatively degraded polysaccharides as water reducing agents in cementitious compositions.

A method for treating aggregate to be used in cement is designed to perform surface treatment on aggregate by bringing fine bubble water containing fine bubbles into contact with the aggregate. The treated aggregate is used as a material for ready-mixed concrete to prepare concrete. The fine bubble water is produced by a high-speed swirling method, a pressure releasing method, or a combination thereof. The dispersibility of the aggregate is improved by the surface treatment.

A method for treating aggregate to be used in cement is designed to perform surface treatment on aggregate by bringing fine bubble water containing fine bubbles into contact with the aggregate. The treated aggregate is used as a material for ready-mixed concrete to prepare concrete. The fine bubble water is produced by a high-speed swirling method, a pressure releasing method, or a combination thereof. The dispersibility of the aggregate is improved by the surface treatment.