Because of the different types of concrete additives, the effects are also different. The general function is to improve the fluidity of the corresponding concrete when the water consumption per cubic meter of concrete or the cement consumption does not change; when the cement consumption remains the same or the concrete slump remains unchanged, the water consumption can be achieved.
Decrease, the strength of concrete is also improved, and the durability of concrete is improved; under the condition of unchanged design strength and constant slump of concrete, it can save cement consumption and reduce cost.
Early strength agent is to improve the early strength of concrete, which is mostly used in emergency repair projects and winter construction; water reducing agent has the effect of reducing water and strengthening while maintaining the consistency of concrete; air-entraining agent mainly reduces the production of concrete during mixing Bleeding segregation caused by air bubbles can improve the workability of concrete; retarder can delay the setting time of concrete, and has the effect of retarding and reducing water. It is mainly used for mass concrete, concrete construction under hot weather conditions or long distance Transported concrete.
Analysis of the influence of admixture water reducer on concrete performance.
Concrete admixture water reducer is mainly composed of surfactants. This surfactant is an anionic surfactant. In fact, the concrete alkali water agent does not have a chemical effect with cement. Its effect on concrete mainly reflects the plasticization of fresh concrete.
Plasticization is the wetting effect, the absorption and dispersion effect and the lubrication effect. The admixture water reducer has the functions of adsorption, dispersion, lubrication and wetting, so it is easy to mix the concrete evenly with a relatively small amount of water, so that the workability of the fresh concrete is improved. This is the admixture water reducer Plasticizing effect on fresh concrete.
Analysis of the influence of admixture air-entraining agent on concrete performance admixture air-entraining agent can introduce a large number of tiny and independent small bubbles into concrete, which can greatly improve the workability of concrete. In terms of the effect of air-entraining agent on the performance of hardened concrete, the strength of concrete will also increase correspondingly from the analysis of water-reducing efficiency; but from the perspective of air-entraining, the strength of concrete generally decreases.
Therefore, the modulus of elasticity of concrete mixed with air-entraining agent or air-entraining water-reducing agent is lower than that without air-entraining agent, and the reduction is greater than the change in strength. The reason is that there are a large number of tiny bubbles in the cement paste, which reduces the elastic modulus of the paste.