First, what is the effect of water-reducing agent on concrete
Concrete construction, water-reducing agent will be added in it, the role of water-reducing agent is to reduce the amount of water required to achieve a certain collapse of concrete, with less water to achieve the required collapse, for concrete, water-reducing agent has four main functions:
1. lubrication
The polar hydrophilic groups in the superplasticizer are directionally adsorbed on the surface of cement particles and are easily associated with water molecules in the form of hydrogen bonds. The force of this hydrogen bond association is much greater than the molecular attraction between the water molecules and the cement particles. When the cement particles adsorb enough water-reducing agent, by means of the association between R-SO3θ and hydrogen bonds in water molecules, coupled with the hydrogen bond association between water molecules, a stable layer of solvent water film is formed on the surface of the cement particles, which plays a three-dimensional protection role, prevents the direct contact between the cement particles, and plays a lubricating role between the particles.
2.wetting effect
When the cement is mixed with water, the surface of the particles is wet by water, and its wetting condition has a great influence on the performance of the newly mixed commercial concrete. When this kind of diffusion wetting occurs naturally, the amount of surface free energy reduction can be calculated by the equation.
3.water reduction effect
The water-cement ratio of commercial concrete can be significantly reduced under the condition of maintaining fluidity by adding human water-reducing agent. The water reduction rate of the water reducing agent can reach 10% to 25%, while the water reducing rate of the ordinary water reducing agent is 5% to 15%, and the water reducing agent is also named for it. The reason of water reducing effect is mainly due to the adsorption and dispersion of commercial concrete on water reducing agent.
4.Plasticization
The fluidity of commercial concrete can be increased while keeping the water cement ratio unchanged by adding human water reducing agent. General water-reducing agent can increase the slump of newly mixed commercial concrete by more than 10cm while keeping the amount of cement unchanged, and the commercial concrete with slump of 25cm can be prepared with water-reducing agent.
二 , concrete without adding water reducer line
Agreed.
Superplasticizer is a kind of concrete admixture, without which concrete can also be formed, but the effect of the same strength level is not good, the concrete density without adding superplasticizer will be relatively low, and the permeability resistance will be correspondingly lower than that of adding superplasticizer. With the advancement of technology, water reducing agents have become the fifth essential concrete material in addition to cement, coarse aggregate, admixtures and water.
Under normal circumstances, if the construction project is on-site mixing concrete, there is no special need to add water reducer, in addition to high-rise buildings; If it is used for commercial mixing, water reducing agents are usually added.
