The hydration heat of cement is the main reason for the early temperature change of concrete. The thermal conductivity of concrete is very low, and the heat released by early hydration of cement is concentrated in the concrete and is not easy to spread. In the cooling stage, the internal temperature of concrete drops to the ambient temperature, and this generates large shrinkage stress. When the shrinkage stress is greater than the tensile strength of concrete, cracks will appear on the concrete surface. In order to ensure the quality of concrete engineering, besides taking appropriate heat reduction measures during construction, it is also necessary to regulate the hydration heat of cement.

To solve the problem of concrete temperature crack and the engineering demand of reducing hydration temperature rise, Sanyuan has carried out the research and development of hydration heat inhibitor and related product technology. It is widely used in the research and development of water temperature rise inhibitor in the construction industry, and has a good prospect in the field of initial temperature rise inhibition of concrete. The material is continuously dissolved and adsorbed on the surface of cement particles in cement alkaline solution. After C₃A reaction in cement is completed, it can significantly inhibit the hydration rate of C₃S in cement particles for 1~2d, effectively regulate the hydration process of cement in acceleration period, avoid concentrated heat release, and reduce the early heat release rate, so as to reduce the internal temperature rise and internal and external temperature difference of concrete. It prevents and controls the development of early temperature cracks in concrete, so as to reduce the risk of concrete cracking.

Cement 7d hydration heat curve

The main innovations of the project are as follows.

lA new type of concrete chemical admixture, hydration heat inhibitor, is developed, which can effectively reduce the internal temperature rise of concrete, reduce the temperature cracks in the early stage of concrete, improve the strength of concrete in the middle and late stage, and play a good effect of temperature control and crack resistance.

lThe concrete preparation guide of hydration heat inhibitor is formed, the engineering application data is summarized, and the application mode of hydration heat inhibitor is standardized.

lA temperature rise measuring device for hydration heat of cement paste is invented. The device has the advantages of simple structure, convenient operation and less demand for labor and raw materials. It is very suitable for the needs of more test formulas and rapid results in the laboratory.

The application of hydration heat inhibitor in cement and concrete can reduce the cracking probability and prolong the service life of the project without changing the concrete raw materials and construction technology. It is an important technical route for the sustainable development of cement concrete industry.

Compared with traditional organic admixtures, hydration heat inhibitors are green and environment-friendly inorganic products, which can improve the safety performance of concrete without any negative effects. Hydration heat inhibitor is suitable for all kinds of structures, especially for projects with large environmental temperature difference, complex corrosive environment and strict requirements for concrete crack resistance. It has a broad application prospect. The product has been applied in many projects in the fields of power construction, water conservancy, transportation, industrial and civil construction, nuclear power and military industry in China. Many engineering applications show that hydration heat inhibitor can effectively reduce the internal temperature rise of concrete and reduce the number of early cracks in concrete.

Cracks of concrete 

Wuhan Sanyuan Special Building Materials Co., Ltd