在冻融或腐蚀环境下混凝土使用寿命预测方法Ⅰ--损伤演化方程与损伤失效模式

SERVICE LIFE PREDICTION METHOD OF CONCRETE SUBJECTED TO FREEZING-THAWING CYCLES AND/OR CHEMICAL ATTACK I-DAMAGE DEVELOPMENT EQUATION AND DEGRADATION MODE

借助损伤力学的原理,通过系统实验研究了混凝土在冻融或腐蚀条件下损伤失效过程的规律与特点。结果表明:混凝土的损伤失效过程可以分为单段损伤模式和双段损伤模式,其损伤曲线主要有直线型、抛物线型和直线—抛物线复合型等3种形式。在此基础上,建立了具有普适意义的混凝土损伤演化方程,提出了损伤速度和损伤加速度的新概念。借助SPSS10.0软件的"聚类与判别分析"模块,得到混凝土损伤失效模式的线性判别函数。通过实验对单一冻融因素作用下混凝土损伤失效模式进行了验证,取得满意的效果。

Based on the results of systematic experiments, the damage development and the characteristics of concrete subjected to freezing-thawing cycles and/or chemical attack were investigated by the principles of damage mechanics. The results show that dam- age of concrete can be represented by either a single-section damage model or a double-section damage model, and the damage curves include a straight line, parabola line and the combination of straight and parabola lines. Based on the results, two new concepts, namely, damage velocity and damage acceleration, were defined and a damage development equation, which can be universally applied, was proposed. By using the clustering and differentiate module of SPSS soiftware, a linear differentiating function, which can be used in the differentiation of concrete damage mode, was obtained. The validity of the damage mode differentiating function was established by data obtained through freezing-thawing experiments.