荷载历史和硫酸盐干湿循环侵蚀作用下混凝土抗压性能试验研究

Experimental study on compressive behaviors of concrete subjected to loading history and sulfate attack in wet-dry cycle environment

为研究荷载历史及硫酸盐干湿循环侵蚀对混凝土单轴抗压性能的影响,对经历不同荷载历史(0、25%、50%极限抗压强度)和不同浓度(5%、10%)硫酸盐干湿循环作用下混凝土试件进行单轴压缩试验,考察材料弹性模量、抗压强度、峰值应变和应力应变关系等力学性能的变化规律。试验结果表明,经历硫酸盐干湿循环侵蚀后的混凝土纵向裂缝数量变多,表层剥落严重;经历硫酸盐侵蚀的混凝土应力应变全曲线形状变得扁平,下降段变得平缓;随着硫酸盐溶液浓度的增大,混凝土抗压强度和弹性模量均降低,但峰值应变增大;相同浓度下,混凝土的抗压强度和弹性模量随着应力水平的增大有降低的趋势,但降低的幅值不明显,峰值应变有增大的趋势。

In order to investigate the impacts of loading history and sulfate attack in wet-dry cycle environment on the properties of con- crete under uniaxial compressive stress state,the uniaxial compressive tests on concrete specimens which have been experienced different stress levels （0,25% and 50% of their compressive strength） and concentrations of sulfate solution （5% and 10%） were carried out.Mechani- cal characteristics of material such as elastic modulus, compressive strength, peak strain and stress-strain curve were analyzed.Experimen- tal results showed that the number of vertical cracks in concrete subjected to the cyclic sulfate attack became more and the surface spalled badly.The shapes of the stress-strain curves subjected to sulfate attack became flat, the descending parts became smoother.With the increase of solution concentration, the concrete compressive strength and elastic modulus decreased, whereas the peak strain increased.The concrete compressive strength and elastic modulus had no obvious trend of decrease with the stress levels increasing in the same solution concentra- tion,whereas the peak strain had a trend of increase.