Self-repairing functional additive for concrete and preparation method of functional additive

Abstract

The invention belongs to the field of building materials and particularly relates to a self-repairing functional additive for concrete and a preparation method of the functional additive. The functional additive is prepared by mixing the following raw materials in parts by weight: 40-60 parts of a polybasic ion complexing agent, 40-50 parts of calcium hydrogen phosohate and 1-5 parts of water-absorbent resin. The functional additive has the advantages of strong self-repairing capacity, good self-repairing effect on wide fissures, high repairing speed and the like, does not has a delayed coagulation effect, is relatively strong in practicability and has relatively strong application and promotion values in the self-repairing field of concrete.

Description

technical field [0001] The invention belongs to the field of building materials, and in particular relates to a concrete self-repairing functional admixture and a preparation method thereof. Background technique [0002] As an important basic building material, cement concrete has been widely used in housing construction, road construction, subway tunnels, bridges, reservoir dams, hydropower stations, docks and other fields. However, concrete is a porous and brittle material, which is prone to internal damage and cracks due to external environmental factors. Damage and cracks will reduce the strength of concrete, aggravate the chemical erosion of concrete, freeze-thaw damage, corrosion of steel bars and alkali-aggregate reaction, and seriously reduce the durability of concrete structures. [0003] In order to improve the durability of concrete structures, more and more attention has been paid to the self-healing technology of concrete damage and cracks. Existing concrete s...

AI Technical Summary

Problems solved by technology

But existing concrete self-repairing function admixture all exists: (1) the sodium citrate that uses, sodium gluconate have very strong inhibitory action to the hydration of cement, belong to typical cement concrete retarder, a small amount of adding will greatly Prolong the setting time of concrete; (2) The chelated products formed by the reaction of sodium citrate, sodium gluconate, etc. (3) There are less free calcium ions and silicate ions in concrete, and the amount of chelated calcium ions such as sodium citrate and sodium gluconate is small, and the ability to carry calcium ions to cracks is weak. Wide cracks cannot be self-repaired; (4) Sodium citrate, sodium gluconate, etc. have a chelation reaction with calcium ions and migrate into the cracks, and the reaction between functional admixtures and silicate ions requires moisture or moisture. However, the self-healing of cracks takes a long time, and the moisture retention capacity of concrete is very weak, and the internal moisture evaporates quickly. Once there is no moisture or moisture in the concrete, the self-healing reaction will stop, and it is difficult to achieve a good repair

The existence of these problems seriously limits the application of functional admixtures in concrete self-healing

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