低活性矿渣内养护水泥砂浆自收缩与电阻率的关系

以预吸水低活性矿渣替代细集料作为内养护材料，研究低活性矿渣内养护砂浆自收缩与电阻率的变化规律，揭示两者的关系。结果表明：随着低活性矿渣掺量的增加，砂浆早期强度降低幅度大，随着龄期的延长，砂浆中后期强度降低幅度小于早期，建议低活性矿渣的合适掺量取为细集料质量的15%~25%；低活性矿渣内养护对砂浆电阻率发展影响明显，凝结硬化前，浆体电阻率随低活性矿渣掺量的增大而增大；凝结硬化后，浆体电阻率随低活性矿渣掺量的增大而减小；低活性矿渣内养护能有效抑制浆体各阶段的自收缩，尤其在快速收缩阶段和短暂膨胀阶段作用最为明显，同时，36 h龄期后电阻率与自收缩有很好的对应关系，可通过电阻率发展趋势预测自收缩的变化情况。

Relationship between autogenous shrinkage and resistivity of cement mortar internal cured with low active slag

Using pre-absorbent low active slag as internal curing material instead of fine aggregate, the autogenous shrinkage and resistivity variation of low active slag internal curing mortar were studied, and the relationship between them was revealed. The results show that with increase of low active slag content, the early strength of mortar decreases greatly, with the extension of age, the strength reduction in the middle and late stages of mortar is smaller than that in the early stage. It is suggested that the appropriate content of low-activity slag is 15%-25% of the fine aggregate quality. The internal curing of low active slag has obvious influence on the resistivity development of mortar. Before setting hardening, the resistivity of mortar increases with the increase of low active slag content. After it, the slurry resistivity decreases with the increase of low active slag content. The internal curing of low active slag can effectively inhibit the autogenous shrinkage at various stages of the slurry, especially in the rapid shrinkage stage and transient expansion stage. At the same time, the resistivity after 36 h has a good correlation with autogenous shrinkage, and the change of autogenous shrinkage can be predicted by the development trend of resistivity.