A special slow-release and controllable polycarboxylate water reducer for crtsⅢ plate self-compacting concrete

Abstract

A preparing method of a slow-release controllable polycarboxylic acid water reducer specially used for self-compacting concrete for CRTSIII type plates is disclosed. The water reducer is prepared by compounding highly-water-reducing type polycarboxylic acid water reducer master batch, I type slow-release polycarboxylic acid water reducer master batch, 2 type slow-release polycarboxylic acid water reducer master batch, 3 type slow-release polycarboxylic acid water reducer master batch, a slow release controlling agent, a retarder, a liquid phase concrete thixotropic agent, a foam stabilizer, a defoamer and an air entraining agent. The water reducer specially used for self-compacting concrete is provided, reduces sensitivity of water using amounts of concrete, improves system performance stability, reduces thixotropic changes and has technical advantages of high water reduction rate, low doping amount, high cement variety adaptability, and the like. Construction difficulties of the self-compacting concrete for the CRTSIII type plates are completely overcome, construction and operation time of concrete is prolonged, and the problem that the self-compacting concrete is high in loss in a construction process is overcome, so that preparation and construction costs of the self-compacting concrete are largely reduced and economic benefit is obvious.

Description

technical field [0001] The invention belongs to the technical field of concrete admixtures, and in particular relates to the preparation of a slow-release and controllable polycarboxylate water reducer specially used for CRTS III plate self-compacting concrete. Background technique [0002] Self-compacting concrete (SCC) has excellent working performance, is free from vibration, and is easy to construct, and has become one of the focuses in the field of high-performance concrete technology. Compared with traditional concrete, self-compacting concrete has excellent fluidity, and self-compacting formwork can be realized without external vibration; at the same time, it also has good anti-segregation performance and gap passing performance, which is convenient for densely reinforced members, thin-walled members and The construction of concealed works ensures that the concrete is dense and uniform after construction, and improves its mechanical properties and durability; due to i...

AI Technical Summary

Problems solved by technology

[0004] At present, domestic and foreign admixture synthesis and preparation technologies have not yet achieved regular release of water-reducing efficiency under different temperature conditions, high-temperature long-term slump retention of self-compacting concrete, concrete thixotropic stability, and low sensitivity to concrete water consumption.

CN103086634B discloses a method for preparing a special water reducing agent for self-compacting concrete of high-speed railway ballastless track. The fluidity of self-compacting concrete prepared by this method is kept for 4 hours, but the problems of stable thixotropic performance and sensitivity to water consumption of concrete are not solved , and the functional design of the molecular structure of the mother liquor has not been used to form the release of the water-reducing efficiency to the response law of the pH value and the ambient temperature; CN100545120C discloses a preparation method of a special admixture for self-compacting concrete, although it improves the self-compacting concrete. Rheological properties and volume stability properties, but the use of naphthalene-based mother liquor does not meet the requirements of mandatory application of polycarboxylic acid in railway high-performance admixtures

These admixtures only focus on improving a certain performance of self-compacting concrete, and cannot fully meet the performance requirements of CRTSSⅢ-type slab filling layer construction for self-compacting concrete performance. The fluidity can be maintained for up to 5 hours under the condition of ℃), and the process requires the concrete to have low sensitivity to water consumption, stable system performance, and small thixotropic changes

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