杂散电流与受压荷载耦合作用下混凝土中的氯离子传输性能

为研究水工混凝土结构在杂散电流与荷载作用下的氯离子传输特性的变化,本文对埋置钢筋的混凝土试件分别设计了杂散电流单独作用以及和压缩荷载共同作用下的电化学腐蚀试验,对不同电流和荷载条件下的氯离子传输特性以及混凝土孔隙结构进行测试,研究了杂散电流和压缩荷载对氯离子传输的影响。试验结果表明:混凝土内的钢筋会促进杂散电流对氯离子传输的加速效应。当压缩荷载一定,随着杂散电流增大,混凝土试件内的氯离子含量明显增加。当杂散电流一定,随着荷载的增大,混凝土试件内的氯离子的传输速率会出现先降低后提高的情况,传输速率开始提高的临界应力水平大致为0.4。此外,在已有研究和试验结果的基础上,推导了考虑压缩荷载和杂散电流作用下的氯离子传输模型,该模型结果与试验数据有较好的一致性。

Influence of stray current and compressive loading on chloride transport in hydraulic structure

In order to study the chloride transport properties of hydraulic concrete structures under the combined action of stray currents and loading, so as to provide references for the durability prediction of hydraulic structures, the electrochemical corrosion tests of concrete specimens with embedded steel bars were designed respectively under the action of stray current alone and combined with compressive loading in this paper. The chloride transport properties and concrete pore structure under different current and loading conditions were tested,and the effects of stray current and compressive loading on chloride transport were studied. The results show that the steel in the concrete will promote the acceleration effect of stray current on the transport of chloride ions. The critical stress level at which the transport rate begins to increase is approximately 0.4. In addition, on the basis of the existing research and test results, the prediction model of chloride transport in concrete under stray current and sustained compressive loading is established and verified by the experimental measurements. It provides reference for durability research and life prediction of hydraulic structure.