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用轴心受拉混凝土试件 ,在标准条件下养护一个月后 ,进行了不同应力水平下轴心受拉徐变破坏试验 ,观测了混凝土在不同应力水平下的轴拉徐变变形过程 ,通过分析得到了对应于不同轴拉应力水平时的混凝土的徐变变形规律 .当持荷应力低于徐变长期强度时 ,混凝土在持续拉伸荷载作用下变形速度缓慢 ,并且不发生徐变破坏 ;当持荷应力高于徐变长期强度时 ,混凝土在持续拉伸荷载作用下的徐变变形随时间的增长不断增加 ,直至发生徐变破坏 .这类徐变变形过程一般可以分为3个阶段 (即徐变减速阶段、稳定徐变阶段和徐变加速阶段 ) .根据试验结果进一步得到了混凝土在轴拉荷载作用下的徐变变形表达式
Tensile concrete specimens with axial compression were tested under normal conditions for one month and then tested for tensile and creep failure under different stress levels. The creep deformation of concrete under different stress levels was observed and passed through The creep deformation law of concrete corresponding to different axial tensile stress level is obtained.When the load-bearing stress is lower than the creep long-term strength, the deformation speed of concrete under the continuous tensile load is slow and creep damage does not occur ; When the load-bearing stress is higher than the creep long-term strength, the creep deformation of concrete under constant tensile load increases with time until the creep failure occurs. Such creep deformation process can generally be divided into three (Ie, creep deceleration phase, steady creep phase and creep acceleration phase). According to the test results, the creep deformation of concrete under axial load is obtained