Retarder matched with magnesia expansive agent and preparation method thereof

Abstract

The invention relates to a set retarder compatible with a magnesium oxide expansion agent, which is prepared by mass percentage of the following substances: 5%~10% of ammonium oxalate; 10%~20% of ammonium phosphate; 20%~20% of ammonium citrate 30%; the balance is water. The invention also relates to a preparation method of the retarder. The retarder compatible with the magnesia expansion agent provided by the present invention can not only improve the initial fluidity of the cement slurry mixed with the magnesia expansion agent, but also can significantly improve the fluidity retention ability of the cement slurry after 60 minutes, and has excellent retarding effect; it can delay the early hydration of magnesia expansion agent, improve the work performance of magnesia concrete, and not reduce the reactivity of magnesia expansion agent, so as to ensure that its expansion performance is not weakened; The preparation method of the retarder compatible with the magnesium expansion agent has the characteristics of convenient procurement of raw materials, simple and easy preparation process, and convenient popularization and application.

Description

technical field [0001] The invention belongs to the technical field of concrete admixtures, and in particular relates to a retarder compatible with a magnesium oxide expansion agent and a preparation method thereof. Background technique [0002] After the concrete is poured, due to the large amount of heat of hydration generated by the hydration of the cement, the temperature of the concrete rises, resulting in volumetric thermal expansion. After reaching the maximum temperature, as the heat dissipates to the external environment, the temperature will drop from the maximum value to a stable or quasi-stable value, and temperature shrinkage stress will be generated. When the shrinkage stress exceeds the ultimate tensile strength of concrete, it will lead to concrete cracking . In the construction of water conservancy and hydropower projects, the temperature shrinkage crack of mass concrete is one of the key factors affecting the quality and durability of the project. Chinese...

AI Technical Summary

Problems solved by technology

Obviously, when this retarder and magnesium oxide expansion agent are used in combination, the magnesium oxide expansion agent will lose its reactivity, resulting in a decrease in its expansion performance.

Moreover, the aluminum hydroxide disclosed in this patent is a relatively insoluble substance, which is easy to precipitate out of the mixed solution, which brings difficulties to use

Images