A high-early-strength polycarboxylate water-reducer for subway segment concrete

Abstract

The invention relates to a high early strength type polycarboxylate water reducer for metro segment concrete. The water reducer is prepared from the following raw materials by weight percent: 30-50% of early strength type polycarboxylate water reducer mother liquor, 3-10% of water reducing excitant, 5-15% of early strength excitant, 0.05-0.5% of de-foaming agent, 2-10% of active catalyst, 0.05-0.5% of thixotropic agent and 20-59% of water. The invention aims to utilize the synergistic effect of the high early strength type polycarboxylate water reducer for metro segment concrete to various regulation techniques, such as, high dispersion, low air bleeding, high reaction speed and high reaction degree of concrete to promote the early strength of the concrete and meanwhile to shorten the setting time of the concrete and properly reduce the gas content of the concrete. The high early strength type polycarboxylate water reducer is especially suitable for the preparation of segment prefabricated concrete. The quick promotion of the early strength and the quick shortening of the settling time are both beneficial to the reducing of the de-molding time of the prefabricated concrete part and the increasing of the template turnover efficiency, so that the production efficiency of the prefabricated part is increased.

Description

technical field [0001] The invention belongs to the technical field of preparation of functional admixtures, and in particular relates to a high-early-strength polycarboxylate water-reducer for subway segment concrete. Background technique [0002] With the rapid development of society and technology, the subway is more and more favored by urban residents for its advantages of speed, punctuality, safety, comfort, large capacity, low energy consumption, and small pollution, and has become the main travel in people's daily life. one of the ways. At present, in the development process of the subway, more and more shield methods are used in the construction of subway projects, so the demand for concrete segments is increasing. The main factors affecting the quality and production efficiency of the segment: one is the bubble problem, which can affect the appearance and reduce the impermeability of the concrete; the other is the crack problem, which can affect the structure and w...

AI Technical Summary

Problems solved by technology

However, because the traditional polycarboxylate-based water reducer will delay the hydration of cement, the early strength of concrete will develop slowly, which limits its use in precast concrete and cold climates.

Patent application number 201310346345.8 discloses a high early strength polycarboxylate water reducer and its preparation method. The water reducer is made of methallyl polyoxyethylene ether, acrylamide, sodium methacrylate, Acrylic acid and acrylated alkanolamine and other monomers are polymerized under the action of initiators and chain transfer agents. This water reducer has problems such as single early strength mode, limited shortening of setting time, and no consideration of the impact on concrete thixotropy.

Patent application number 201610820468.4 discloses a coagulation-accelerating early-strength polycarboxylate-based water reducer for subway shield segments. This water reducer also has the technical problem of failing to consider the high thixotropy of subway segment concrete. At the same time, there is also the problem of high sensitivity of polycarboxylate water reducer

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