Special additive for inhibiting concrete alkali-aggregate reaction

Abstract

The invention relates to a concrete additive, particularly to a special additive for inhibiting a concrete alkali-aggregate reaction. Active fine powder is used as a carrier, and the multiple compounding technologies such as air entraining (lignosulfonate), water resistance (stearate), water reduction (lignin), early strengthening (nitrate) and the like are adopted. The cost of the additive is greatly lower than that of the foreign lithium salt additive. The doping amount of the inhibitor is 2-4% of cement aiming at high, medium and low activities of aggregate under different alkali content conditions, and the inhibitor has good inhibitory effect. The higher the activity of the aggregate alkali is, the more obvious the inhibitory effect is. The higher the content of concrete alkali is, the more obvious the inhibitory effect is. After the inhibitor is added into concrete, the overall performance is increased, the workability is improved, the slump loss is reduced, 28d strength is increased, the durability such as freezing resistance, seepage resistance and the like is increased, the harms of steel bar corrosion and the like do not occur, the service life of concrete is prolonged, the use safety of concrete is ensured, and the social benefit is great.

Description

[0001] technical field [0002] The invention relates to a concrete admixture, in particular to a special admixture for inhibiting concrete alkali-aggregate reaction. Background technique [0003] Durability is an important performance index of concrete, which is related to the service life and safety of concrete engineering. The alkali-aggregate reaction is caused by the destructive expansion reaction between the sand and stone aggregate in the concrete and the alkali in the system, resulting in the cracking and failure of the concrete structure. Moreover, because the damage of this reaction lasts for a long time and is irreparable, many scientists in the world call it the "cancer" of concrete. Since the destructive factor was discovered in the 1940s, it has caused a large number of engineering damages and huge losses. A series of projects in my country from the 1980s to the early 1990s also caused serious losses due to the damage of the alkali-aggregate reaction, such as...

AI Technical Summary

Problems solved by technology

[0006] Although foreign countries have successfully developed chemical admixtures to inhibit the alkali-aggregate reaction, only lithium salts have been developed, which are expensive and difficult to promote