Early-strength polycarboxylate superplasticizer and preparation method thereof

Abstract

The invention discloses an early-strength polycarboxylate superplasticizer, which is prepared through aqueous solution polymerization on 75-90% of monomer A, 0.5-2.0% of monomer B, 0.8-3.2% of monomer C, 5-20% of monomer D and 1-3.5% of monomer E under action of an oxidation-reduction system. A preparation method comprises the following steps: 1) putting the monomer A, the monomer B and the monomer E into a reaction kettle, heating to 30 DEG C, stirring to uniformly dissolve into water, heating to 50 DEG C and adding an oxidant; 2) respectively dripping a mixed aqueous solution of the monomer C and the monomer D and a mixed aqueous solution of a reductant and a chain transfer agent, dripping off within 2-4 hours at the same time, maintaining the temperature at 50 DEG C, and further stirring for 1 hour; and 3) cooling to room temperature, adding water and liquid alkali, and regulating pH to 5-6.5 and the solid content to about 40%. The early-strength polycarboxylate superplasticizer has significant early strength enhancing performance, and the middle strength and the later strength thereof are stably improved; and the preparation method is easy to operate, short in production cycle and low in cost.

Description

technical field [0001] The invention belongs to the technical field of concrete admixtures in building materials, in particular to an early-strength polycarboxylate high-performance water reducer, and in particular to a preparation method of the water reducer. Background technique [0002] Compared with traditional naphthalene-based and melamine-based water-reducing agents, polycarboxylate-based water-reducing agents have gradually become a new generation of water-reducing agents that are widely researched and used due to their advantages such as low dosage, high water-reducing rate, and good cement adaptability. . With the rise of my country's nuclear power, water conservancy, bridges, tunnels and other large-scale infrastructure, especially the planning and implementation of the national railway passenger dedicated network project, the market demand for polycarboxylate water reducers continues to grow. At present, the common polycarboxylate superplasticizer has a certain ...

AI Technical Summary

Problems solved by technology

When inorganic salt or organic early strength agent is used for physical compounding with polycarboxylate-based water-reducer, not only is it prone to delamination, flatulence, poor storage stability, etc., but it will also reduce the water-reducing performance of polycarboxylate-based water-reducer

Sulfates in inorganic salts will greatly increase the alkali content, resulting in potential alkali-aggregate reaction hazards, and sulfates have a negative impact on the later strength of concrete; chloride salts are restricted because they are easy to cause corrosion of steel bars; alcohol amines in organic matter are early-strength The early strength effect is not obvious when the agent is mixed alone, the price is expensive and the dosage is not easy to control

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