摘 要：为探究修复剂对高温后混凝土性能的改善作用，通过试验研究修复剂种类和用量、修复养护时间、修复方式、温度、混凝土强度等级以及降温方式等对混凝土抗压强度、强度修复因子Rf和抗渗修复因子Rc 的影响。结果表明，聚氨酯的修复效果最好，硫化硅橡胶的修复效果最差；修复剂用量越多修复效果越好，浸泡法比涂刷法的修复效果好，且浸泡时间越长修复效果越好；随着温度的升高，Rf 和Rc 逐渐增大，当温度超过700℃时，Rf 急剧增长，修复剂对混凝土强度和抗渗性能的改善作用明显增强；修复剂对C20混凝土的修复效果优于C60混凝土；修复养护时间越长，修复效果越好，自然降温后的Rf 和Rc大于洒水降温。高温修复后，裂缝处的Ca(OH)2含量大幅降低，水化硅酸钙和CaCO3晶体含量相对上升；修复作用使裂缝表面的CaCO3和Ca(OH)2结晶体向C-S-H凝胶转变。
Abstract: In order to explore the role of repair agent to improve the performance of concrete after high temperature, through test, the effects of repair agent type and amount, repair curing time, repair mode, temperature, concrete strength and cooling methods on concrete compressive strength, repair intensity factor Rf and impermeability repair factor Rc are studied. The results show that the repair effect of polyurethane was best, and the repair effects of silicone rubber was worst, the more repair dosage, the better restoration, and the immersion method is better than brushing method for repair effect, and the longer soaking, the better repair effect. As the temperature increases, Rf and Rc increases gradually, and when the temperature exceeds 700℃, Rf grows rapidly, and the repair agent can improve the concrete strength and impermeability significantly. The repair agent for C20 concrete is better than that of C60 concrete, the longer repair curing time, the better repair effect, and Rf and Rc of natural cooling are more than that of sprinkler cooling. After the high temperature repair, the Ca(OH)2 content at cracks significantly reduced, hydrated calcium silicate crystals and CaCO3 content increased, and CaCO3 and Ca(OH)2 crystals in the crack surface turned to C-S-H gel transition with repair effect.