Chinese Academy of Sciences

Liwei Zhang

Yan Wang

Xiaochun Li

Manguang Gan

Kaiyuan Mei

The present disclosure provides a modified montmorillonite self-repairing agent and a preparation method and use thereof, and belongs to the technical field of cement repairing materials. Montmorillonite is mixed with water, such that water is fully adsorbed between montmorillonite layers. The structure of montmorillonite is modified by supercritical COtreatment at a temperature of 50-60° C. and a pressure of 8-12 MPa, and the self-repairing efficiency of cement is improved by adding the modified montmorillonite into cement. Supercritical COis adsorbed by montmorillonite, such that the montmorillonite is activated and an interlayer distance is increased to improve the repairing efficiency. When a crack is formed in cement, the adsorbed supercritical COin montmorillonite is released into the crack and combined with positive ions to generate carbonate deposition, such that the crack is sealed and the self-repairing activity of the cement is improved. Results of examples show that carbonate microcrystals are generated in the modified montmorillonite self-repairing agent provided by the present disclosure. The generated carbonate microcrystals serve as 'active sites' that induce additional carbonate precipitation, which is beneficial for crack sealing.

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Wuhan, China

Liwei Zhang