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针对MMA基混凝土修补材料固化时的高收缩性,研究了低收缩剂PVAc对MMA基混凝土修补材料固化收缩的改善作用。采用红外光谱分析(IR)、扫描电镜分析(SEM)、体积收缩和黏结强度实验对改性修补材料进行了结构和性能分析。结果表明:当PVAc树脂溶液掺量为12%时,MMA基混凝土修补材料的体积收缩率最低,为3.5%;改性修补材料黏结强度最高达到4.8 MPa,断裂面产生在砂浆试件内部。阐述了低收缩添加剂减缩机理,PVAc颗粒在修补材料固化时,周围产生微孔隙,从而减少固化收缩。
Aiming at the high shrinkage of MMA-based concrete repairing materials during curing, the effect of low shrinkage agent PVAc on the curing shrinkage of MMA-based concrete repairing materials was studied. The structure and properties of modified materials were analyzed by infrared spectroscopy (IR), scanning electron microscopy (SEM), volume shrinkage and bond strength. The results show that when the content of PVAc resin solution is 12%, the volume shrinkage of MMA-based concrete repair material is the lowest, 3.5%. The bond strength of the modified repair material reaches up to 4.8 MPa, and the fracture surface is generated inside the mortar specimen. The shrinkage mechanism of low shrinkage additive was expounded. When PVAc particles were cured, micropores were formed around them to reduce the curing shrinkage.