超早期混凝土与结构物之间的切向作用机制  

Tangential interaction mechanism between very early-age concrete and structures

作　　者：崔溦[1] 杨娜娜[1] 宋慧芳[1] 

机构地区：[1]天津大学水利工程仿真与安全国家重点实验室,天津300072

出　　处：《水力发电学报》2016年第2期101-108,共8页Journal of Hydroelectric Engineering

基　　金：国家自然科学基金创新研究群体科学基金(51321065);国家自然科学基金(51279126);天津市自然科学基金(13JCQNJC06800)

摘　　要：超早期混凝土与结构物之间的相互作用受混凝土组分、结构物表面性态、水化时间、相对运动速度、润滑条件等诸多方面影响,其作用机制非常复杂。在理论分析的基础上,设计了一个可以测量不同条件下模板起拔力的模型试验,并对试验结果进行了分析,结果表明:早期混凝土与模板之间的切向作用主要由粘结力和摩擦力组成,初始切向力主要来源于水泥砂浆的粘结作用;随水灰比减小,切向力与时间相关性增加;随混凝土水化进程,初始切向力增加明显,且切向力变化与时间相关性亦有所增加;拔板速度变化对切向力影响较小;润滑剂的使用可明显减小初始切向力,并可使中后期切向力随时间基本保持不变。建立了一个混凝土与模板相互作用的细观模型,从细观角度对试验结果进行了解释。Interaction mechanism between very early-age concrete and structures is very complicated, as it is effected by composition of concrete, behavior of structure surface, setting time of concrete, demoulding velocity, and lubricating condition. In this study, we have designed and conducted model tests for the measurements of tangential force at the interface of concrete and formwork in different conditions and analyzed the test data. The experimental results showed that the tangential force had two components, i.e. frictional force and bonding force, and at initial stage it largely came from the bonding effect of cement mortar. Its correlation with time became stronger as water-cement ratio decreased, while along with concrete setting, it increased significantly and the correlation also slightly increased. Demoulding velocity had little influence on this force, while lubricant could help to decrease it at initial stage and keep it steady in mid-late stages. To interpret the experimental results, we developed a micromechanical model for the interaction mechanism between concrete and structures.

关 键 词：超早期混凝土 模板 切向作用力 模型试验 细观模型 

分 类 号：TU528[建筑科学—建筑技术科学]