Superplasticizer is essentially a kind of building materials, in use will produce foam and bubble and other sol bubbles, and they have different characteristics and formation mechanism, is caused by ionic superplasticizer. After adding the superplasticizer to the concrete, the superplasticizer will be adsorbed on the surface of cement particles.
Generally, about 80% of the superplasticizer will be adsorbed by cement particles, which can keep the aggregation state without diffusion for a long time.Without superplasticizer in concrete , concrete will have a certain amount of air (2% or so), the size of the bubbles formed is uneven, and the distribution is very uneven.When superplasticizer is added to concrete, the distribution of concrete parameters can maintain good properties and improve the working performance of concrete, such as tensile strength of concrete.
In addition, adding superplasticizer in concrete mixing can help reduce the water consumption in concrete mixing, and the tiny sol air bubbles generated can help fill in the micro pores inside concrete, significantly improve the impermeability of concrete, and enhance its chemical corrosion resistance and aging resistance.The water-reducing agent can be integrated into the free water migration of internal materials, which is helpful to ease hydrostatic pressure and enhance the ability of concrete to resist repeated freezing-thawing cycle.
Water-reducing agent can slow down the hydration reaction rate of cement in the middle and late stage, improve the strength of cement and enhance its anti-expansion performance.Therefore, when mixing concrete, in addition to considering sand, stone, cement and other conventional materials, appropriate addition of a certain amount of water reducer to improve the performance of concrete.