Expansive agent for preventing concrete from cracking

Abstract

The invention relates to a concrete anti-cracking expansion agent, a concrete anti-cracking expansion agent. Its notable feature is that in the process of cement coagulation and hydration reaction, the expansion speed is compatible with the cement reaction speed, and the product provides appropriate expansion force. , to offset the volume shrinkage caused by cement hydration reaction, so as to achieve the purpose of preventing concrete cracking. The invention has the advantages of high expansion energy, stable performance, low alkali content, low dosage, low production cost, excellent product performance and technical indicators complying with national standards. The expansion rate of the concrete anti-crack expansion agent is basically the same as the cement hydration reaction rate. The expansion rate is moderate in each period of the concrete curing reaction, and the long-term performance of the concrete is stable, which can effectively prevent the appearance of concrete cracks. ideal admixture.

Description

Technical field: [0001] The present invention is a concrete and mortar technology field, especially a concrete crack anti -inflated agent involving concrete cracking technology. Background technique [0002] In the early stages of condensation and hydration, a chemical reaction will generate crystal compounds. Since the crystallization compound is smaller than the volume of the raw material, it will cause the concrete volume to shrink.Cracking concrete. [0003] The concrete expansion agent occurs when the concrete starts to shrink or causes micro -expansion before starting to shrink, and applies compressive stress to the concrete component to offset, weaken or balances the stress caused by shrinkageThe purpose of appearing and avoiding cracking. [0004] At present, most of the expansion agents on the market are calcium alum stones prefabricated by burn kaolin, alum stones, ground stones, aluminum slag, aluminum calcium chroma or calcium sulfate clinker and gypsum.Speed and conc...

AI Technical Summary

Problems solved by technology

[0004] Most expansion agents on the market are calcined kaolin, alunite, dickite, aluminum slag, calcium aluminate clinker or calcium sulfoaluminate clinker and gypsum The prepared ettringite expansion agent has disadvantages such as low expansion energy, mismatch between the expansion rate and the hydration reaction rate of concrete condensation nuclei, large dosage, and high alkali content, which can easily cause alkali-aggregate reaction; Calcium oxide expansion agents have disadvantages such as too fast expansion speed, short expansion time, incongruity between expansion and concrete shrinkage rates, and difficulty in preservation; magnesium oxide expansion agents with MgO as the main component have the disadvantages of slow expansion speed and slow expansion start time. It is far behind the start time of concrete shrinkage, and cannot play the role of anti-cracking and other disadvantages

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