基于体积稳定性的混凝土综合抗裂模型

基于非荷载作用下混凝土的开裂现象，系统分析了混凝土体积稳定性的控制参数及其影响因素，根据变形限制状态下混凝土因环境温湿度变化而产生的内应力具有粘弹性特征，推导了应力松弛系数的数学表达式．在综合考虑混凝土的抗拉强度、徐变特征以及环境温湿度变化引起的总应变的基础上，建立了混凝土的抗裂模型．提高混凝土的抗拉强度傅性模量比、降低混凝土的线膨胀系数和干燥收缩系数是保证混凝土体积稳定性、增强混凝土抗裂性能的有效途径．工程应用的结果验证了混凝土综合抗裂模型的可行性和合理性．

Comprehensive Crack-Resistance Model of Concrete Based upon Volume Stability

The control parameters and the influence factors of concrete volume stability are systemically analyzed on the basis of the cracking phenomena of concrete without applied load. According to the fact that the internal stress of concrete induced by the environmental changes such as temperature and moisture under confined deformation is viscoelastic, an expression of the coefficient of stress loss is proposed. Based upon tensile strength, creep property and total strain induced by the environmental changes such as temperature and moisture, a comprehensive crack-resistance model of concrete is set up. Increasing tensile strength to elastic modulus ratio, reducing coefficients of thermal expansion and dry shrinkage are efficient for improving volume stability and crack resistance of concrete. The feasibility and rationality of the comprehensive crack resistance model of concrete are validated by a case study.