A modified calcium oxide cement concrete expansion agent and its preparation method

Abstract

The invention discloses a modified calcium oxide cement concrete expansion agent. The expansion agent is composed of a phenolic resin, a modified rosin resin and a calcium oxide expansion clinker. The phenolic resin and the modified rosin resin work together to wrap the The surface of the calcium oxide-based expanded clinker, wherein the phenolic resin and the modified rosin resin account for 0.01%-10% of the total mass of the modified calcium oxide-based cement concrete expansion agent. Calcium oxide expansion clinker is modified by a specific ratio of phenolic resin and modified rosin resin to effectively adjust the hydration process of the anti-crack expansion agent. The modified rosin resin is water-soluble and compatible with the phenolic resin. The combination can not only ensure the expansion rate in the early stage, but also slowly release the expansion agent in the later stage, which can significantly improve the durability of concrete.

Description

technical field [0001] The invention belongs to the field of concrete building materials, in particular to a modified calcium oxide cement concrete expansion agent and a preparation method thereof. Background technique [0002] Cement concrete is currently the largest building material in the world, with low price and wide application. However, cement concrete is easy to shrink and crack, and the cracks will cause the steel bars in the concrete to corrode, shorten the service life of the engineering structure, and seriously affect the durability of the concrete. In order to solve the problem that cement concrete is easy to shrink and crack, researchers have invented expansive cement or cement concrete expansion agent. [0003] Since the invention of expansive cement in France in the 1930s, especially since Japan separated the expansive component on the basis of expansive cement as a separate expansion agent, the concrete expansive agent has gradually developed into the larg...

AI Technical Summary

Problems solved by technology

The modification method of the calcium oxide expansion agent protects the expansion agent to a certain extent, but because the fatty acid can be oxidized and decomposed into CO 2 and H 2 O, it is easy to cause the expansive agent to be consumed before the concrete develops strength

[0006] Calcium oxide as an expanded clinker was first invented and popularized in Japan. There are relatively few domestic studies on using calcium oxide as an expanded clinker. One reason is that the expanded clinker is prone to moisture absorption and fails, and the storage period of the clinker is short. The shelf life of the finished expansion agent is short; another main reason is that the calcium oxide expansion agent hydrates rapidly, and most of the expansion energy is consumed in the plastic stage before the strength of the concrete, doing useless work; it is necessary to improve the calcium oxide expansion agent, how to delay The contact between calcium oxide expansion agent and water, reducing its ineffective consumption in the plastic stage of cement concrete, and increasing the effective expansion energy of concrete after hardening is one of the difficulties in the research and performance improvement of expansion agents.

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