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2.1概述热应力计算和预测裂缝危险性需要输入许多数据,如混凝土热的性质和力学性质。然而,最重要的混凝土早期性能,如弹性模量和应力松弛,是在一个很宽的范围持续变化的。这些性质的发展变化无法用普遍适用的方程式预测,因而混凝土早期的应力计算很容易出错。在近几年中,人们尝试了两种新方法。2.1.1试验室的约束应力试验采用专用设备(开裂试验架或温度应力试验机)直接检测由温度变化和收缩引起的混凝土约束应力与开裂倾
2.1 OVERVIEW CALCULATION OF THERMAL STRESS AND PREDICTION OF CRACK RISK It is necessary to input many data such as the thermal and mechanical properties of concrete. However, the most important early properties of concrete, such as modulus of elasticity and stress relaxation, continue to vary over a wide range of areas. The development and changes of these properties can not be predicted by universally applicable equations, so early concrete stress calculations are prone to error. In recent years, people have tried two new methods. 2.1.1 Constraints in the laboratory Stress tests using special equipment (cracking test rack or temperature stress testing machine) directly detected by the temperature changes and shrinkage caused by the constraints of concrete confinement and cracking