拉应力对低水胶比混凝土抗碳化性能的影响

Influences of Tensile Stress on Anti-carbonation of Concrete with Low Water-Binder Ratio

为了更准确预测承载混凝土结构碳化耐久性,采用拉应力-碳化耦合加载装置及空气渗透测定仪研究了不同拉应力水平对90d龄期低水胶比混凝土碳化性能的影响规律.结果表明:材料层次和构件层次低水胶比混凝土碳化速度均随拉应力水平提高呈EXP指数增加,材料层次碳化速度明显高于构件层次混凝土碳化速度,随着拉应力水平的提高,材料层次与构件层次的碳化速度差值越来越大;低水胶比混凝土空气渗透系数与拉应力水平之间也呈EXP指数关系,这可从机理上解释不同拉应力水平对低水胶比混凝土碳化性能的影响规律.

In order to accurately evaluate anti-carbonation capability of loading concrete structures, the tensile loading devices coupling with carbonation were adopted to investigate the anti-carbonation capability of concrete with low water-binder ratio exposed to different tensile stress levels. The results show that the carbonation rate increases with the increased tensile stress levels at the mode of exponential function. The carbonation rate of concrete at material-level is higher than that at member-level and the difference gets much greater with the increased tensile stress levels. Moreover, the relationship between air permeability coefficient and tensile stress level could he used to explain the mechanism of effects of tensile stress level on anti-carbonation capability of concrete.