受力状态下混凝土试件碳化试验研究

Experimental Research on Carbonation of Forced Concrete Specimens

摘要:

为了研究混凝土桥梁的碳化规律，采用加速碳化试验方法，进行了碳化环境下受力状态混凝土试件的耐久性试验，分析了碳化混凝土结构的退化机理和规律。结果表明：拉、压应力分别加快和减缓了混凝土碳化的速率，且应力变化越大，碳化速率的改变就越大；桥梁常用C50强度混凝土的碳化深度远小于低强度混凝土，但C50强度混凝土受拉时的相对碳化深度大于低强度混凝土。根据试验结果修正了现有混凝土碳化深度预测模型中的工作应力影响系数。当混凝土桥梁的裂缝宽度满足规范要求时，裂缝对混凝土碳化的影响很小；预应力混凝土桥梁的耐久性能优于钢筋混凝土桥梁。

Abstract:

For the purpose of research on carbonation regularity of concrete bridges, the durability experiments of forced concrete specimens in accelerated carbonation corrosive environments were carried out. The degradation mechanism of carbonized concrete structure was analyzed. The results show that tensile or compressive stress can accelerate or slow down carbonation rate, respectively. Larger changes of stress will cause larger changes of carbonation rate. The carbonation depth of bridge-common used C50 strength concrete is far smaller than low strength concrete but the relative carbonation depth of C50 strength concrete applied tensile stress is larger than low strength concrete. According to the tests, the working stress influence coefficient in existing concrete carbonation depth prediction model was modified. The crack in concrete bridges has little effect on concrete carbonation if its width can meet standard requirements, and the durable performance of prestressed concrete bridges is better than reinforced concrete bridges.