High-efficiency CSA expansive agent is obtained by mixing suitable natural hard stone with special clinker mainly composed of calcium sulfoaluminate and CaO. CSA expansive agent is mainly mixed with ordinary cement. When mixed with ordinary cement in an appropriate ratio and hydrated, the cement mortar or concrete will expand in the early stage of hydration. When this expansive is restricted, the drying shrinkage can be minimized. In addition, when the ratio of shrinkage reducing admixture to ordinary cement increases, its high expansive quality makes it an ideal choice for prestressed concrete. CSA expansive agent is being used in various parts of the construction field and various concrete product manufacturers.
CSA expansive agent and ordinary cement must be fully and uniformly mixed with aggregate and water in a mechanical mixer, and the mixing time is slightly longer than ordinary concrete. In order to ensure the normal development of ettringite needle crystals, which is important to prevent shrinkage cracks during drying, it is recommended to spray water or film curing on the concrete surface at least 14 days after the concrete is poured.
1. Features of CSA expander: low alkalinity. The alkali content of CSA expansive agent is very low (R20<0.3%), which is beneficial to avoid AAR in concrete. In short-term stable expansive stage, the stable expansive period does not exceed 14 days without affecting the ultimate strength of concrete. The dosage is small and the expansive ability is strong. The general dosage of CSA expansive agent is 6-8% of the weight of ordinary cement, which is lower than other expansive agents such as UEA and CEA (the dosage is about 10-12% of the weight of cement).
2. Features of using CSA expansive agent: CSA expansive agent prevents cracking due to drying shrinkage and heat of hydration, and increases the water tightness of concrete, so it can be used for building waterproofing. CSA expansive agent can make high-strength concrete products through chemical prestress
