After mixing cement with water, hydration reaction occurs and flocculent structure appears, which wraps a lot of mixing water, thus reducing the workability of fresh concrete (also known as workability, mainly refers to the construction of fresh concrete, that is, in the process of mixing, transportation and irrigation, it can maintain uniformity, compactness without stratification and separation. Analyzing the performance of phenomena. In order to maintain the required workability in construction, it is necessary to increase the mixing water volume accordingly. As the increase of water volume will cause excessive voids in the cement-stone structure, which will seriously affect the physical and mechanical properties of hardened concrete. If these wrapped water can be released, the water consumption of concrete will be greatly reduced. In the process of preparing concrete, adding a proper amount of water reducing agent can play such a good role.
When water reducer is added into concrete, hydrophobic groups of polycarboxylic acid superplasticizer liquids are adsorbed on the surface of cement particles, while hydrophilic groups are adsorbed on the surface of cement particles, forming monomolecular or multi-molecular layer adsorbing films. Because of the directional adsorption of surfactants, the surface of cement particles has the same symbolic charge. Under the action of homogeneous repulsion, not only can the cement-water system be in a relatively stable suspension state, but also the flocculating structure formed in the initial stage of water addition can be dispersed and disintegrated, so that the flocculating structure can be formed in the flocculating structure. Water is released to reduce water consumption. After adding water reducing agent, not only the workability of fresh concrete can be improved, but also the pore volume of cement paste can be significantly reduced, the cement paste is more compact and the compressive strength of concrete can be significantly improved due to the dramatic decrease of water cement ratio in concrete. The addition of water reducing agent also affects the hydration rate and setting time of cement. These properties are very important in practice.