高温影响下新老混凝土粘结的剪切性能试验研究

为了研究高温对新老混凝土粘结性能的影响,本文对既有混凝土经历高温后再与新混凝土粘结和新老混凝土粘结后再经历高温两种类型的Z形粘结试件进行了剪切试验研究,总结了影响粘结面剪切性能因素(温度、冷却方式、界面粗糙度和界面剂)的影响规律,提出了温度对粘结面剪切强度和剪应力滑移关系的影响计算公式,建立了高温后粘结剪切强度的多因素统一计算公式。在试验的基础上,分析了高温对新老混凝土粘结的损伤机理,并给出了火灾后混凝土结构进行粘结修补的建议。

Experimental research on shear behavior of young and old concrete bonding subjected to high temperature

In order to research the influence of high temperature on young and old concrete bonding performance, this paper presents the shear tests to study the two types of Z-shaped adhesive specimens: the old concrete was heated first then bonded to the younger one; the young and old concrete were bonded first then heated together. The influencing regularities of several main factors including temperature, cooling process, roughness of interface and interface adhesive on adhesive shear property were summarized. The calculation formulas of adhesive shear strength and shear stress-slipping relationship subjected to high temperature have been presented. The multi-factor unified formula for bonding shear strength has been established. Based on tests, the damage mechanism of high temperature to young and old concrete bonding was analyzed. Furthermore, the rational suggestions are put forward for bonding repair of concrete structures after fire.