Effect of Water Reducer on Shrinkage Cracking of Commercial Concrete

2019-08-30 17:10:20

With the continuous improvement of society and productivity technology, in the construction industry, the quality and performance requirements of concrete are more stringent, and the quality of the building is directly affected by the performance of concrete.

The invention of concrete admixtures has greatly improved this problem.The commercial concrete added with the water reducing agent has greatly improved the working performance, improved the strength of the concrete, and enhanced the durability and service life of the concrete, which is a great achievement for the construction industry.

Water reducing agents are widely used in various key infrastructures, especially high-rise buildings, super high-rise buildings, high-speed railways, highways, subway stations, nuclear power plants, etc., which promote the rapid development and strong protection of construction industry.

The water reducing agent is an additive which can significantly reduce or greatly reduce the concrete mixing water during the concrete mixing process, improve the fluidity and the strength of the concrete.Practice has proved that if the water-reducing agent is added to the concrete, if the strength is not required to be increased, the amount of cement can be greatly reduced, and the compactness of the concrete can be improved.Therefore, the water reducing agent is an indispensable additive material in commercial concrete.

In order to further improve the economic benefits of commercial concrete, concrete production enterprises like to use water-reducing agents with higher water-reducing properties to improve the strength of concrete or to greatly reduce the amount of cement and reduce production costs.

In fact, this is a major misunderstanding. Although water reduction is beneficial to improve the compressive strength of concrete, excessive water reduction can also adversely affect the flexural strength of concrete.

Although proper water reduction is conducive to reducing the concrete shrinkage rate, it must be noted that when designing the concrete mix ratio, the water reducing function of the superplasticizer has been considered, and the water-to-binder ratio of the general design is low, such as further reduction. The amount of water used will increase the concrete shrinkage and increase the concrete shrinkage.

When the commercial concrete greatly reduces the amount of cement, although the compressive strength is not lowered, the tensile strength decreases as the volume of the hardened cement stone in the concrete decreases.

Due to the reduction in the amount of cement, the concrete grout layer is too thin, which will cause more microcracks in the concrete.Of course, microcracks have little effect on concrete compressive strength, but the effects on concrete tensile and other properties cannot be underestimated.The large reduction in cementitious materials also affects the elastic modulus and creep of the concrete, making the concrete more susceptible to cracking.When producing commercial concrete, the concrete water reduction rate and the amount of cementitious materials must be considered comprehensively. Never reduce water or excessively reduce the cementitious material.

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