Water reducer, also known as dispersant plasticizer, is a widely used admixture, mainly used in the mixing of concrete. Water reducing agents can improve the structure and process of concrete, increase workability and hardening performance, and can also save cement, save energy, increase strength, shorten the construction period, speed up turnover, etc.
Water reducing agent can reduce water consumption per unit without affecting concrete workability. Or in the condition of not changing the unit water consumption, can improve the workability of concrete, or have the above two effects at the same time, and do not significantly change the gas content. At present, the concrete water reducing agent used are surfactants, belonging to anionic surfactants. After the cement and water mix, produce hydration reaction, along with some flocculation structure which contains a lot of mixing water, which reduces the workability of fresh concrete (also known as the workability, mainly refers to the fresh concrete in the construction, that is, in the process of mixing, transportation, watering can keep even, dense and not stratified segregation phenomenon performance). In the construction, in order to maintain the required workability, it is necessary to increase the amount of water mixing. As a result of the increase of water quantity can make cement stone structure form excessive pores, which seriously affect the physical and mechanical properties of hardened concrete. If this encased water can be released, the water use of concrete can be greatly reduced. In the process of preparing concrete, adding proper amount of water reducing agent can play such a role well. According to the composition of materials, water reducing agent can be divided into water sulfonate, polynuclear aromatic salts and water-soluble resin sulfonate. Sort by setting time it can be divided into standard type, early strength and retarding type. In accordance with the participation of composition, it can be divided into ordinary water reducers, superplasticizers, early strength water reducer and air-entraining water reducing agent.
The main effect of water reducing agent on concrete:
- Keep the concrete water consumption constant, which can increase the fluidity of the mixture
- Keep fluidity, the amount of cement unchanged, reduce water consumption, reduce the water-cement ratio, and increase the strength of concrete.
- Keep the strength and fluidity unchanged, and reduce the amount of cement used when reducing water, which can save cement.