PH-Sensitive Microgels with Different Chemical Structures of Internal Curing of Cementitious Materials

Abstract

Cracking risk of cementitious materials remains one of the serious problems in the construction and highway field. Here, a series of pH-sensitive microgels with different anionic content and crosslinking density have been successfully synthesized and applied in cement mortar. The absorption behavior and pH sensitivity of microgel in aqueous solutions were determined. The effects of microgel on hydration degree, autogenous shrinkage, and compressive strength of cement mortar were studied. Experimental results indicate that the microgel exhibits less desorption in the pore solution and releases water timely in pH from 12–13. Despite the different anionic content of microgels, the addition of microgel with moderate crosslinking density is 0.19%∼0.31%, which can alleviate the autogenous shrinkage of cement mortar. The compressive strength of mortar can be increased by about 5.7 MPa by the microgels with low anionic content and moderate crosslinking density, thereby showing excellent internal curing effect.