Polycarboxylic acid water reducer for preparing fair-faced concrete

Abstract

The invention discloses a polycarboxylic acid water reducer for preparing fair-faced concrete. The water reducer is composed of following components in percentage by weight: 5.00% to 60.00% of polycarboxylic acid copolymer, 0.02% to 1.00% of slow-release antifoaming agent, 0.01% to 1.00% of antifoaming agent, 0.01% to 1.00% of air-entrainer, 0.00% to 10.00% of delayed coagulant, and the balance being water. The polycarboxylic acid water reducer for preparing fair-faced concrete has the characteristics of low mixing amount, low air-entraining, low consistency, continuous defoaming ability, and improvement on concrete uniformity, is capable of producing green concrete, which has the advantages of excellent construction performance, low consistency, and good concrete wrapping ability, and also can produce fair-faced concrete, which has a mirror-face effect.

Description

technical field [0001] The invention relates to the field of building material additives, in particular to a polycarboxylate water reducer for preparing concrete. Background technique [0002] Fair-faced concrete, also known as decorative concrete, gets its name because of its great decorative effect. It belongs to one-time pouring molding, without any external decoration, and directly uses the natural surface effect of cast-in-place concrete as the finish. It requires a smooth surface, uniform color, sharp edges and corners, and no damage and pollution. Foreign countries began to use fair-faced concrete as early as the Japanese Olympic Stadium in the 1960s, and later developed to the exterior walls of the Sydney Opera House, the Japanese National Grand Theater, the Paris Prehistoric Museum, and until the current elevated bridge decks and bridge columns in the light rail .... In China, fair-faced concrete technology was first applied to bridges, water conservancy projects,...

AI Technical Summary

Problems solved by technology

At present, general-purpose polycarboxylate water-reducers are used in the preparation of most clear-water concretes. The use of such water-reducers often has the following problems: when the polycarboxylate water-reducers used in pumping concrete are used in clear-water concrete, Good workability of fresh concrete can be obtained, but it is often achieved by introducing air bubbles, which will eventually cause more apparent air bubbles in the concrete. If defoamers are added on this basis, the initial workability of fresh concrete will be lost. It affects the construction quality of concrete, causing problems such as missing corners and construction holes; and if the polycarboxylate superplasticizer used in prefabricated parts is used, fresh concrete with low initial air content can be obtained, but because the initial slump of fair-faced concrete is greater than For prefabricated concrete, this kind of water reducing agent is easy to segregate and bleed the concrete under the condition of high fluidity, resulting in severe stratification and serious color difference in the appearance of concrete

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