高延性水泥基材料(ECC)开裂后渗透性研究综述

Summary of research on the permeability of Engineered Cementitious Composites(ECC)after cracking

高延性水泥基材料(ECC)是突破了传统混凝土脆性及应变软化属性的变革性的工程结构材料,该材料的拉伸延性与裂纹控制功能决定其适用于构件拉应力区带裂纹服役。开裂ECC的裂纹宽度对于工程耐久性至关重要,如何在保留材料延性的同时更有效地降低裂纹宽度是进一步提升ECC耐久性的关键。文章总结了该材料自研发以来取得的多种裂纹调控方法,指出其裂宽自控能力与延性的不匹配问题,分析了裂纹宽度、纤维掺量、纤维混杂等因素对开裂水泥基材料渗透性的影响,综述了ECC材料独特的开裂渗透规律及其理论预测模型,进一步提出混杂高模量纤维协同聚乙烯醇纤维调控微裂纹的方法,以期为ECC开裂抗渗性与延性的匹配设计、ECC结构的耐久性提升提供借鉴。

Engineered Cementitious Composites(ECC)is a revolutionary engineering structural material that breaks through the brittleness and strain-softening properties of traditional concrete.The tensile ductility and crack control ability of the material result in its applicability to the tensile part of structural members in cracked state.The crack width of cracked ECC is very important for engineering durability,and how to reduce the crack width more effectively while retaining its ductility is the key to further improving the durability of ECC.This article summarizes various crack control methods that obtained since the development of ECC,points out the mismatch between crack width control ability and ductility,analyzes the influence of crack width,fiber content,fiber hybridization and other factors on the permeability of cracked ECC,and reviews the unique cracking permeability law of ECC and its theoretical prediction model.Meanwhile,a regulation method of microcrack through blending high-modulus fiber and PVA fiber is further proposed to provide references for matching of cracking resistance and ductility of ECC,and improving the durability of ECC structure.