Crystalline nucleus early-strength polycarboxylic acid water reducer and preparation method thereof

Abstract

The invention relates to a crystalline nucleus early-strength polycarboxylic acid water reducer and a preparation method thereof. The water reducer comprises the following components in percentage byweight: 10-20% of tricalcium silicate, 20-30% of carboxylic acid vinyl copolymer and 50-70% of deionized water. The preparation method comprises the following steps: adding tricalcium silicate, carboxylic acid vinyl copolymer and deionized water into a ball mill according to proportion, adding zirconia grinding balls, and performing ball milling to obtain the crystalline nucleus early-strength polycarboxylic acid water reducer with a median particle size of less than or equal to 500nm. The crystalline nucleus early-strength polycarboxylic acid water reducer provided by the invention integratesthe advantages of the water reducer and the early-strength agent, the main raw materials are tricalcium silicate and polycarboxylic acid water reducer, which will not cause strength decreasing in thelater stage, the water reducer is mixed into ordinary portland cement mortar according to the mixing amount of 1.0-2.0%, so that the water reduction rate can reach more than 30% and the 12h strengthincrease ratio can reach more than 250%. The preparation method is simple in process, easy to control the process parameters and easy to popularize.

Description

technical field [0001] The invention belongs to the technical field of concrete admixtures, and relates to a crystal nucleus early-strength polycarboxylate water reducer and a preparation method thereof. Background technique [0002] Concrete early strength agent is a kind of concrete admixture, it can promote the early hydration of cement, improve the early strength of concrete, early strength agent can be divided into organic type, inorganic type and compound type according to the composition. Traditional early strength agents are mostly inorganic, such as chloride, sulfate and nitrite, but the addition of chloride ions will form an electrode potential between it and the steel bar, which will easily cause steel bar corrosion; Na in sulfate + and K + Does not participate in the cement hydration process, so its soluble salts will remain in the concrete system, and sodium or potassium salts are easy to precipitate from the surface after the concrete loses water and dry, and ...

AI Technical Summary

Problems solved by technology

Traditional early strength agents are mostly inorganic, such as chloride, sulfate and nitrite, but the addition of chloride ions will form an electrode potential between it and the steel bar, which will easily cause corrosion of the steel bar; Na in the sulfate + and K + Does not participate in the cement hydration process, so its soluble salts will remain in the concrete system, and sodium or potassium salts are easy to precipitate from the surface after the concrete loses water and dry, and even crystallize on the concrete surface, causing the concrete surface to expand and crack; Then developed organic early strength agents such as alcohol amines, calcium formate and composite early strength agents. Organic early strength agents themselves will not cause damage to concrete, but the reaction mechanism of organic concrete early strength agents is more complicated. , it is difficult to grasp the regularity of the early strength effect and the dosage of the agent, so it is rarely used alone in practical applications

In addition, the high price is also one of the restrictive factors that prevent the widespread use of organic accelerators.

[0003] Nowadays, water reducers and early strength agents are generally used in combination in concrete, and the mechanism of action of water reducers, especially polycarboxylate water reducers, is to adsorb on the surface of cement particles to provide dispersibility, but this also brings A certain degree of retardation makes it difficult to achieve super early strength

Images