A kind of micro-expansion concrete and preparation method thereof

Abstract

The application relates to the field of concrete, and specifically discloses a micro-expansion concrete and a preparation method thereof. A slightly expansive concrete, comprising the following raw materials in parts by weight: gravel: 850-930, sand: 790-910, cement: 280-360, admixture: 85-135, ettringite-based expansion agent: 25-35 , pumping agent: 6-12, inhibitor: 31-44, drinking water: 150-210, the inhibitor is compounded by chitosan, capsule wall material and pH regulator; its preparation method is: Crushed stone, sand and cement are added to the mixer, after stirring for 5 minutes, add admixture and ettringite-based expansion agent, after stirring for 5 minutes, add pumping agent and drinking water, after stirring for 10 minutes, add inhibitor, and stir for 4 minutes to obtain micro-expansion concrete . The micro-expansion concrete of the present application can be used for pouring large-volume concrete, and has the advantages of reducing secondary generation of ettringite and reducing cracking of large-volume concrete.

Description

technical field [0001] The invention relates to the concrete field, more specifically, it relates to a kind of micro-expansion concrete and a preparation method thereof. Background technique [0002] Micro-expansion concrete refers to the addition of a certain expansion agent to ordinary concrete, so that the concrete can expand to a certain extent during the hydration period by relying on the action of the expansion agent, thereby making up for the shrinkage of the concrete, preventing concrete cracks, and improving concrete performance. Purpose. [0003] Authorized notification number is that the Chinese invention patent of CN102674735B discloses a kind of non-shrinkage cement mineral admixture, comprises alunite, coal cinder and gypsum, also comprises foaming agent and waterproofing agent, and its each component mass percent is alunite: coal cinder: Gypsum: foaming agent: waterproofing agent = 20-30%: 40-60%: 10-20%: 1-5%: 0.1-0.3%, the sum of each component is 100%, usi...

AI Technical Summary

Problems solved by technology

[0004] When the above-mentioned non-shrinkage cement mineral admixture is used in the production of mass concrete, the following problems exist: when the cement hydration releases heat, the internal temperature of the mass concrete continues to rise up to 80°C, and at this temperature, the ettringite decomposes into monosulfide Calcium aluminum sulfate hydrate, aluminum ions and sulfate ions, aluminum ions and sulfate ions are adsorbed by the C-S-H gel produced by cement hydration at this temperature, when the temperature drops to room temperature, aluminum ions and sulfate ions are condensed from C-S-H The glue is detached and the secondary formation of ettringite with monosulfide-type hydrated aluminum calcium sulfate causes expansion. At this time, the cement has completed hydration and hardened, and the volume expansion of the formed ettringite causes cracking in the concrete.

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