一、前言拉力下混凝土的应力应变(σt—ε)行为对弄清混凝土材料的内部结构与力学行为的关系有着重要意义。尽管直接拉伸试验比较困难,国外一些学者仍就此做了不少工作。但到目前为止,对拉力下混凝土σt—ε行为的描述尚不一致,认识也不统一。国内在这方面 I. Introduction The behavior of stress and strain (σt-ε) of concrete under tension is important to understand the relationship between internal structure and mechanical behavior of concrete materials. Although direct tensile tests are difficult, some foreign scholars have done a lot of work on this. But so far, the description of the behavior of concrete σt-ε under tension has not been consistent and the understanding is not uniform. Domestic in this area