冻融循环作用后钢筋混凝土柱的偏心受压性能

Eccentric compressive behaviors of RC columns after freeze-thaw cycles

为了研究冻融循环作用对钢筋混凝土柱偏心受压性能的影响,对经历0,75,100,125,150次冻融循环作用后的立方体试块进行了抗压强度试验,并设计制作了30根钢筋混凝土柱,将其经历0,75,100,125,150次冻融循环作用后进行偏心受压静力试验.分析了混凝土相对抗压强度、质量损失率、相对动弹性模量与冻融循环次数的关系,研究了冻融循环次数、轴向力偏心距对钢筋混凝土柱偏心受压性能的影响.研究结果表明,随着冻融循环次数的增加,试验柱的开裂荷载和极限荷载都逐渐减小,极限变形逐渐增大,部分试件由大偏心受压破坏转变为小偏心受压破坏.现行混凝土结构设计规范关于钢筋混凝土偏心受压柱极限承载力的计算理论适用于冻融循环作用后的钢筋混凝土柱.

To investigate the eccentric compressive behaviors of reinforced concrete （RC） columns after freeze-thaw cycles, compressive strength tests of concrete cubes after 0, 75, 100, 125, 150 freeze-thaw cycles were carded out. Then, 30 RC columns were fabricated, and the corresponding static eccentric compressive experiments after 0, 75, 100, 125, 150 freeze-thaw cycles were carried out. The relationships between the relative compressive strength of concrete, mass loss rate, relative dynamic elastic modulus and the number of freeze-thaw cycles were analyzed, respectively. The in- fluences of the number of freeze-thaw cycles and the eccentric distance of axial force on the compres- sive behaviors of RC columns were studied. The results show that with the increase of the number of freeze-thaw cycles, both the cracking load and the ultimate load of RC columns decrease while the deflection increases gradually. Moreover, large eccentric compression failures of some specimens turn into small eccentric compression failure. The current concrete structure design code about the ul- timate load is still suitable for RC columns after freeze-thaw cycles.