A kind of magnesia high-efficiency anti-cracking agent for cement concrete, its preparation method and application

Abstract

The invention discloses a magnesian efficient anti-cracking agent for cement concrete and a preparation method and application thereof. The magnesian efficient anti-cracking agent comprises a magnesian expanding component and a cement hydration heat regulating component filling pores inside the magnesian expanding component and covering the surface of the same, a mass ratio of the cement hydrationheat regulating component to the magnesian expanding component is 6:94-20:80, and the cement hydration heat regulating component is dextrin. The magnesian efficient anti-cracking agent overcomes adverse impact of high-activity magnesia expanding materials on concrete workability, and the problems that slump of concrete after being doped with high-activity magnesia is lowered and slump loss is bigare solved; expanding efficiency of high-activity magnesia is improved; inside pores impede contact area of cement alkaline solution, a cement hydration heat regulating material is slowly released, and temperature control effect is improved obviously when compared with the prior art.

Description

technical field [0001] The invention belongs to the technical field of concrete admixtures for building materials, and particularly relates to a magnesia, temperature-controlled high-efficiency anti-cracking agent for cement concrete, a preparation method and application thereof. Background technique [0002] Crack control of concrete is one of the most important problems in construction engineering, and temperature shrinkage crack is the most common form of concrete crack. After the concrete is poured, a large amount of hydration heat is generated due to the hydration of the cement, which increases the temperature of the concrete and generates thermal volume expansion. After reaching the maximum temperature, the concrete temperature will decrease from the maximum value to the ambient temperature as the heat is dissipated to the external environment. This temperature reduction will cause the concrete to shrink, and under the constraint conditions, when the tensile stress fo...

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Problems solved by technology

[0013] In the prior art, when magnesium oxide clinker (especially high-activity magnesium oxide) is mixed into concrete, there is an increase in the amount of water-reducing agent under the same slump condition, and the problems affecting workability such as accelerated loss of concrete slump; The heat of hydration regulating material prepared by dextrin in the technology is easy to be alkalized and dissolved under the condition of cement alkaline solution, and cannot be released slowly and fully exerts the heat of hydration regulating effect. The present invention provides a magnesium material for cement concrete. High-efficiency anti-cracking agent and preparation method thereof

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