弯曲荷载作用下硫酸钙晶须混凝土碳化研究

钢筋混凝土桥梁在服役期间，梁体受荷载作用可能会产生开裂，这种开裂会使外界环境的侵蚀作用更加严重。文章开展弯曲荷载作用下硫酸钙晶须混凝土的碳化试验研究，分析加载级别、硫酸钙晶须掺量对混凝土碳化速率的影响。试验结果表明：掺加硫酸钙晶须的混凝土抵抗碳化的能力比普通混凝土有明显提升；随着晶须掺量的增加，混凝土抵抗碳化的能力有所下降；弯曲荷载作用下，试件受压区碳化深度明显小于受拉区碳化深度，并随着弯曲荷载的增加，差距更为显著；基于硫酸钙晶须在混凝土中的荷载分担作用和弯曲荷载作用下混凝土梁截面的受力特性，考虑应力在截面上的不均匀分布，建立弯曲荷载作用下硫酸钙晶须混凝土的碳化计算公式。

Research on carbonation of CSW concrete under flexural loadings

In-service reinforced concrete bridges are prone to cracking under service loads, which would aggregate the corrosion from its environment. In this paper, experiment were conducted to study the carbonization of calcium whisker concrete under flexural loads, in which the influence of loading level and whisker quantity on the carbonization rates of concrete was analyzed. The research results indicate that the calcium whisker concrete has significantly improved anti carbonization performance than the plain concrete. As the quantity of whisker increases, the anti-carbonization performance drop slightly. The carbonization depth in the compression zone of the bending specimens are found obviously smaller than that in the tension zone, and this discrepancy grows with the flexural loads. Considering the whisker’s contribution to the stress and the stress distribution in the cross. section of a flexural specimen, a time-dependent carbonization model is established.