Composite expanding agent for cement-based non-shrinkage grouting material

Abstract

The invention discloses a composite expanding agent for a cement-based non-shrinkage grouting material. The composite expanding agent is prepared by the following raw materials in weight proportion through dry-mixing: 45 to 60 parts of calcium aluminate powder, 20 to 40 parts of anhydrite, 0.4 to 0.8 part of azo compound, 0.4 to 1.2 parts of lithium-containing compound, 6 to 16 parts of calcium hydroxide and 0 to 1.5 parts of additive. The composite expanding agent prepared in the invention is stable in property and high in efficiency, and has excellent rigid expanding and plastic expanding properties; when the composite expanding agent is used in the cement-based non-shrinkage grouting material, the high expanding rate can be obtained by a small adding amount; the drying shrinkage of the cement at the later period is compensated effectively, the cracking is avoided, consequently, the strength of the grouting material is improved, and furthermore, the stabilizing time is short and the dependence on wet maintaining is low; in addition, the preparation method is simple, the source of raw materials is wide, and the cost is low, therefore, the composite expanding agent is suitable for industrialized production.

Description

technical field [0001] The invention belongs to the technical field of cement-based material admixtures, and in particular relates to a composite expansion agent for cement-based non-shrinkage grouting materials. Background technique [0002] Cement-based non-shrinkage grouting material has the characteristics of good self-flow, rapid hardening, high strength, micro-expansion, non-toxic and harmless, no aging, no pollution, anti-rust, convenient construction, etc. It is widely used for anchoring anchor bolts, fixing nuclear power equipment, Secondary grouting of equipment foundation, reinforcement and transformation of embedded reinforced concrete structures, crack treatment of old concrete structures, etc. In order to obtain ideal reinforcement, anchorage and crack treatment effects, in addition to good fluidity, fluidity retention performance and strength performance requirements, cement-based grouting materials need to produce a certain plastic expansion before setting an...

AI Technical Summary

Problems solved by technology

Chinese patent CN102491669C discloses a kind of p-nitrobenzene diazonium fluoroborate, iminodiacetonitrile, N, N-dicyclohexyl-2-phenylbuthiazole sulfenamide compound as gas-generating components, hard The preparation method of a special plastic expansion agent with fatty acid ester as the coating component and potassium hydroxide or lithium hydroxide as the catalytic component can realize the high-efficiency plastic expansion of 3 hours and meet the requirements of the difference between the vertical expansion rate of 3 hours and 24 hours. At the same time, the release of hydrogen gas is also avoided, but this method requires a complicated preparation process, and the difference in the vertical expansion rate between 24h and 3h is actually produced by the plastic expansion of the gas, resulting in a lower compressive strength of the grout

[0005] In addition, the ettringite expansion source cannot provide effective plastic expansion, and the plastic expansion or insufficient rigid expansion of the grouting material cannot achieve the expected use effect. Therefore, the cement-based non-shrinking grouting material with excellent performance needs to have both high-efficiency plastic expansion and rigidity. expand

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