Modified calcium sulfoaluminate-calcium oxide concrete expansion agent and preparation method therefor

Abstract

The invention discloses a modified calcium sulfoaluminate-calcium oxide concrete expansion agent and a preparation method therefor and belongs to the technical field of production of compound concreteexpansion agents. The modified calcium sulfoaluminate-calcium oxide concrete expansion agent specifically comprises a calcium sulfoaluminate-calcium oxide expansion clinker and a modifier which are in a weight-ratio addition level of (80 to 90): (10 to 20), wherein the modifier is prepared from the following ingredients in parts by weight: 30-40 parts of sodium silicate, 10-15 parts of silane coupler, 10-15 parts of carboxymethyl cellulose, 5-10 parts of nano calcium carbonate and 20-45 parts of anhydrous ethanol. According to the modified calcium sulfoaluminate-calcium oxide concrete expansion agent and the preparation method therefor, through optimizing a proportioning ratio of green stock, the ratio of calcium sulfoaluminate to free calcium oxide in the expansion clinker can be in therange of (30: 50) to (50: 30); meanwhile, through modifying the expansion clinker with the modifier, the hydrating speed of the calcium oxide is lowered; and volume expansion resulting from hydrationof the calcium sulfoaluminate also plays a certain role in compensating later-stage contraction deformation of concrete, the volume of the concrete can be continuously and uniformly expanded, early-stage and later-stage contraction of the concrete can be effectively compensated, and thus, the strength of a concrete structure is guaranteed.

Description

technical field [0001] The invention relates to the technical field of composite concrete expansion agent production, in particular to a modified calcium sulfoaluminate-calcium oxide concrete expansion agent and a preparation method thereof. Background technique [0002] Concrete is a heterogeneous and brittle material. After pouring, the cement will emit a large amount of heat of hydration during the hydration process. Since the heat cannot be dissipated quickly, tensile stress will be caused on the surface and inside. When these tensile stresses exceed the limit of concrete When the tensile strength is increased, cracks will appear. Experimental research and engineering application show that introducing a certain amount of expansion agent into concrete can produce moderate expansion, which can effectively eliminate or reduce the shrinkage of concrete. At present, the most widely used expansion agents mainly include sulfoaluminate, calcium oxide and composite expansion age...

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