Modified polycarboxylic acid composite water reducing agent for steam-curing-free and steam-pressing-free PHC tubular pile

Abstract

The invention discloses a modified polycarboxylic acid composite water reducing agent for a steam-curing-free and steam-pressing-free PHC tubular pile. The modified polycarboxylic acid composite water reducing agent for the steam-curing-free and steam-pressing-free PHC tubular pile consists of the following raw materials in percentages by mass: 30-60% of a polycarboxylic acid water reducing agent and 70-40% of a polycarboxylic acid modified aliphatic water reducing agent, wherein the water reducing rate of the polycarboxylic acid water reducing agent is greater than or equal to 45%, and the polycarboxylic acid modified aliphatic water reducing agent is a polycarboxylic acid modified aliphatic water reducing agent disclosed in the patent of CN100340518. A viscosity reducer and a defoamer can also be added in the modified polycarboxylic acid composite water reducing agent, the addition amount of the viscosity reducer is 1-5% of the total mass of the polycarboxylic acid water reducing agent and the polycarboxylic acid modified aliphatic water reducing agent, and the addition amount of the defoamer is 0.2-1.0% of the total mass of the polycarboxylic acid water reducing agent and the polycarboxylic acid modified aliphatic water reducing agent. The modified polycarboxylic acid composite water reducing agent for the steam-curing-free and steam-pressing-free PHC tubular pile effectively reduces water-binder ratio of concrete, and has characteristics of quick dispersion and low viscidity to meet requirements of strength of concrete of the PHC tubular pile, so that a curing process of normal-pressure steam curing and high-temperature steam pressing for the concrete of the PHC tubular pile is omitted.

Description

technical field [0001] The invention relates to the technical field of concrete, in particular to a modified polycarboxylate composite water reducer for fully autoclaved autoclaved PHC pipe piles. Background technique [0002] In the production of PHC pipe piles, atmospheric pressure steam curing or autoclave pressure steam curing is the key process to determine the quality of PHC pipe piles. At present, there are two commonly used maintenance processes for the production of PHC pipe piles: one is the traditional production process, that is, the normal pressure steam is first cured at a temperature of 60°C to 70°C for 4h to 7h, then demoulded, and then placed in an autoclave. Continuing curing in the middle, the steam pressure is 0.9MPa ~ 1.0MPa, the steam temperature is about 180 degrees, and it lasts 7h ~ 10h; the second is to use non-autoclaved powder or ultrafine mineral powder to replace the mineral powder above S95 in the pipe pile concrete or ground Sand is only cure...

AI Technical Summary

Problems solved by technology

This method meets the requirement of avoiding autoclave curing, but uses expensive raw materials such as microbeads and silica fume, and at the same time, the water-cement ratio is too low, the concrete is viscous, and it is difficult to produce

On March 9, 2016, an authorized patent number CN105384409A "a kind of concrete for PHC pipe piles without autoclaving" was disclosed. 2-5% silica fume and our own patented special cement are used to increase the strength of concrete, and a small amount of sodium gluconate is added to control the slump loss of concrete, and at the same time, there is a strict gradation of sand and gravel in concrete Requirements, the pressure steaming process is eliminated, but the steaming process is also retained

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