How to Select CSA Cement Additive

CSA cement has a fast hydration speed, and the ettringite formed in the early hydration stage will quickly cover the water reducing agent on the cement particle surface, which reduces the effective content of water reducing components in the cement slurry. The superficial area of ettringite is much larger than that of cement particles, and ettringite also has strong adsorption to water-reducing components, which leads to a high mixing content of saturation point of water reducing components.

Although CSA cement has good characteristics such as early strength, high strength, freeze resistance, anti-permeability, corrosion resistance, and low alkalinity, the problems in great slump loss of CSA cement concrete, unmanageable setting time, and poor slurry fluidity make it difficult to meet the construction requirements in practical engineering, which seriously hinders the widespread use of CSA cement.

Generally speaking, although the retarded components can affect the early strength of CSA cement, they can appropriately improve the later strength. The early strength of CSA cement has a certain adverse effect on its later strength development. From the results of the study, boric acid is the most recommended retarded component for CSA cement.

There are adaptability problems between water reducer and CSA cement, so it is necessary to preferentially select the type of water-reducing agent with better dispersing effect, slump protection, and strengthening effect.

For CSA cement, it should be effective to solve the problems in the practical application of CSA cement by the compound mixing of water reducing agent components, retarded components, early strength agent components composition, and other necessary components, however, due to the special mineral composition and hydration process of CSA cement, mature measures for Portland series cement cannot be completely copied in the specific compound mixing scheme for CSA cement.