应力和干湿循环共同作用下硫酸根在混凝土中传输试验研究

Experiment on Sulfate-ion Diffusion in Concrete under Combined Actions of Stress and Wetting-Drying Cycles

对混凝土试件施加应力后,按一定周期将其在硫酸钠溶液中浸泡,再风干形成干湿循环作用。采用钻芯、分层切片、研磨提取水泥石粉末样本进行化学分析,测定不同深度处混凝土的硫酸根离子含量;研究在干湿循环作用下,混凝土受到的拉应力、压应力对硫酸根离子在混凝土内传输的影响规律。结果表明:拉应力对硫酸根离子由外部侵蚀溶液向混凝土内的传输具有加速效果,且随拉应力水平的增加而增大;压应力对硫酸根离子在混凝土内的传输具有一定的抑制作用,但与压应力水平没有确切的相关性。

After the concrete specimens were exerted in stress states, they were immersed into suifate sodium solution and then air dried according to certainly period. That forms the action of wetting-drying cycles. The samples were made by drilling,cutting into slices and grinding into powder,and tested by the chemical analysis method. The sulfate-ion content in different depth of the concrete specimens were measured, the effects of tensile stress and compressive stress on diffusion of sulfate-ion in concrete were studied. It is proved that the sul- fate-ion diffusion from outer solution into concrete is accelerated by the tensile stress ,and tends to be quicker with the increase of stress level. Oppositely, it is confined by the compressive stress, but no certain relationships with the level of it.