基于微观结构分析的高性能混凝土高温后抗压强度试验研究

EXPERIMENTAL STUDIES ON COMPRESSIVE STRENGTH OF HPC SUBJECT TO HIGH-TEMPERATURE BASED ON MICROSTRUCTURE ANALYSIS

对高温作用后的高性能混凝土进行微观结构扫描电镜试验及抗压强度试验,研究高性能混凝土微观组织结构与其宏观力学性能之间的关系。试验结果表明,混凝土微观结构的变化与其宏观力学性能一致,随温度的升高,混凝土集料从致密逐渐变得疏松,裂纹逐渐增多,裂纹宽度变大,且相互贯通,宏观力学性能随之下降。合成纤维熔化后在基体中留下可减轻混凝土内部蒸汽压力的孔道,从而降低了高温对混凝土的损伤。

The experiment of microstructure SEM and compressive strength of HPC after exposure to high temperatures was performed and the relationship between microstructure and mechanical properties of HPC was investigated. The results show that the variation of microstructure in concrete is in conformity with the change in mechanical properties. With the temperature increased, concrete aggregates change from compact to loose, the microcrack is increased and interconnected in quantity and width, and the mechanical properties are decreased accordingly. The vapor pressure of inner-concrete is decreased due to interconnected pores after polypropylene fiber melted, which can alleviate the damage of high temperature to concrete.