高温作用后ECC力学性能和微观分析研究进展

Research progress on mechanical properties and microanalysis of ECC after exposed to elevated temperatures

高延性纤维增强水泥基复合材料(Engineered Cementitious Composites,ECC)因具备抗裂和增韧的优势成为新型建筑材料行业关注的热点。高温作用(火灾)后ECC性能衰减程度对于其在民用建筑中的进一步应用至关重要。本文基于已有的相关试验结果,对不同种类纤维增强ECC力学性能和微观分析的研究进展进行了综述。分析结果表明:当作用温度超过纤维的熔点,纤维会发生熔融进而使ECC的力学性能出现劣化;纤维熔融留下的孔洞减小了ECC高温爆裂发生的机率,提升了ECC的耐高温性能;内部的孔隙率变大以及C-S-H凝胶脱水是ECC强度损失的主要原因。

High ductility fiber reinforced Engineered Cementitious Composites(ECC) have become the focus of new building materials industry due to their advantages of crack resistance and toughness. The degradation degree of ECC performance after high temperature action(fire) is very important for its further application in civil buildings. In this paper, based on the existing test results, the research progress of mechanical properties and microscopic analysis of ECC reinforced by different kinds of fibers is reviewed. The analysis results show that when the operating temperature exceeds the melting point of the fiber, the fiber will melt and the mechanical properties of ECC will deteriorate. The holes left by fiber melting reduce the probability of high temperature bursting of ECC and improve the high temperature resistance of ECC. The increase of internal porosity and dehydration of C-S-H gel are the main reasons for ECC strength loss.