轴拉荷载作用对粉煤灰混凝土抗氯离子侵蚀性的影响

Influence of an applied uniaxial tensile stress on chloride penetration resistance of fly ash concrete

通过氯离子侵蚀试验,对轴拉荷载作用下粉煤灰混凝土抗氯离子侵蚀性能进行了研究。结果表明:采用适量的粉煤灰等量取代水泥可以改善混凝土的孔结构,增加混凝土的密实性,提高混凝土抵抗氯离子侵蚀的能力;但过高的粉煤灰掺量,反而对提高混凝土的抗渗性有不利影响。短期轴拉荷载作用后,由于混凝土内部微裂缝的扩展和形成,混凝土抗氯离子侵蚀的能力下降。拉应力水平越高,氯离子含量和侵蚀深度增加越明显。但同级荷载水平作用下,粉煤灰掺量对混凝土抵抗氯离子侵蚀能力的影响仍遵循前述规律,可见,材料组成是影响混凝土抗腐蚀能力的最主要因素。

The resistance to chloride penetration of fly ash concrete under uniaxial tensile load was studied through chloride penetration experiment.The result showed that using the right amount of fly ash as an equal replacment to cement could improve the pore structure of the concrete and increase the compactness of the concrete.Then improve the ability of concrete resistance to chloride penetration.However,much high fly ash content would have an adverse effect to improve the permeability resistance of concrete.After uniaxial tension unloaded,the chloride penetration resistance of fly ash concrete would be decreased due to the development and formation of internal microcracks.The higher the tensile stress level was,the higher the chloride concent was and the deeper the penetration depth was.Under the same grade of tensile load,the influence rule of fly ash replacement on the chloride penetration resistance of concrete was similar to that mentioned above.Thus it can be seen that material composition is the most important factor effecting the corrosion resistant ability of concrete.