电阻率法研究引气剂对水泥浆体化学收缩及氯离子渗透性的影响

研究了引气剂对硅酸盐水泥浆体的电阻率、化学收缩、物理力学性能及氯离子渗透性的影响。结果表明,掺入引气剂使水泥浆体的流动度增大,凝结时间延长,早期水化速率加快,化学收缩增大。水泥浆体的电阻率在凝结前随着引气剂掺量的增加而增大,在硬化后则随着掺量的增加而减小。在28d龄期时,0.04%掺量内的引气剂对硬化浆体的抗压强度影响较小,其强度损失率低于5%,氯离子迁移系数随掺量的增大而减小。随引气剂掺量的变化,水泥浆体的电阻率与化学收缩、抗压强度和氯离子迁移系数均存在很好的定量关系。通过水泥浆体的电阻率发展曲线可以预测其化学收缩、强度与氯离子渗透性的变化规律。

Research on effect of chemical shrinkage and chloride permeability of cement pastes with air entraining agent by electrical resistivity method

The evolution of electrical resistivity, chemical shrinkage, physical and mechanical properties and chloride permeability of the Portland cement pastes with air entraining agent were studied. The results show that the air entraining agent is added to increase the fluidity of the cement pastes and prolong the setting time, the early hydration rate and chemical shrinkage increases. With the increase of dosage of air entraining agent, the electrical resistivity of the cement pastes increases before setting and decreases after hardened. At 28 d, the dosages of air entraining agent have a little effect on the compressive strength of the hardened pastes within 0.04%, and its loss rate is less than 5%, the chloride diffusion coefficient decreases as its dosage increases. With the change of the dosage of air entraining agent, the electrical resistivity of cement pastes has a good quantitative relationship with chemical shrinkage, compressive strength and chloride diffusion coefficient. The variation of the chemical shrinkage, strength and chloride permeability can be predicted by the electrical resistivity development curve of the cement pastes.