环境因素对砂浆裂缝自愈合的影响

Influence of Environmental Conditions on Self-healing of Mortar Cracks

设计在自然空气、相对湿度95%、干湿循环和浸水4种不同环境中的自修复条件,探究它们对水泥砂浆裂缝自愈合的影响;采用光学显微镜观察、超声波脉冲速度以及相对动弹性模量测试手段表征砂浆裂缝在不同环境中的自修复效率,利用热重分析和微观形貌分析研究自愈合产物的类型及作用机理。结果表明:液态水的存在有利于未水化水泥颗粒的继续水化和碳酸钙的结晶沉淀;干湿循环和浸水环境能使宽度约为250μm的裂缝完全愈合,而空气和相对湿度95%的环境中的裂缝愈合效果较差。

Four different types of self-healing environmental conditions of air, relative humidity of 95%, dry-wet cycles, and water-immersion were designed to explore the self-healing effect of mortar cracks. The self-healing effect of mortar cracks in different environments was characterized by using the optical micrograph observation, ultrasonic pulse velocity, and relative dynamic elastic modulus. The types of self-healing products and the formation mechanisms were studied by using thermal gravimetry and micro-morphology analyses. The results show that the liquid water is conducive to the continued hydration of the unhydrated cement particles and is also beneficial to the precipitation of calcium carbonate. Dry-wet cycles and water immersion conditions make the cracks around 250 μm healed completely. The self-healing effects in the air and relative humidity of 95% conditions are poor.