A kind of progressive expansion liquid expansion agent and preparation method thereof

Abstract

The invention discloses a step-by-step expansion liquid expansion agent and a preparation method thereof. The liquid expansion agent is prepared by the following steps: Step 1: Weigh the mixture of nano-magnesium oxide powder, butanol, Span 80 and water at 30 Stir at a constant temperature of ~40°C for 1 hour; step 2: heat up to 50~70°C, add polyacryl alcohol 400, simethicone and shrinkage reducing components in sequence, and stir for 1~2 hours; step 3: add polyacrylamide, stir for 1 hour ~2h, aging at constant temperature for 1h, and cooling to room temperature to obtain a step-by-step expansion liquid expansion agent. The expansion component in the liquid expansion agent of the present invention is formed by modifying and mixing magnesium oxide powder fired at different temperatures of 700°C, 900°C and 1100°C. The magnesium oxide powder is mixed and ground to the nanometer level, and fired in three different The hydration time of magnesium oxide powder at different temperatures can achieve the effect of gradual expansion; compounding with shrinkage reducing components can significantly increase the volume expansion of concrete, reduce the volume shrinkage of concrete, and improve the crack resistance and impermeability of concrete.

Description

technical field

[0001] The invention belongs to the technical field of building materials, and relates to an expansion agent, in particular to a liquid expansion agent with a high expansion rate and a preparation method thereof. Background technique

[0002] During the pouring and hardening process of cement-based cementitious materials, volume shrinkage will be caused by chemical shrinkage, cold shrinkage and dry shrinkage, and even cracking of the material will occur in severe cases. Add fiber, pulverized fly ash or slag powder and expansion agent into concrete to solve the shrinkage and cracking problems of concrete. However, fiber-mixed concrete is cumbersome and costly, and the amount of finely ground fly ash and slag powder is large, which requires high cost and cannot completely solve the shrinkage and cracking of concrete. However, expansion agent is a kind of chemical additive. When mixed into concrete, when the concrete sets and hardens, it expands and blocks capi...

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