高强混凝土经轴压和硫酸盐侵蚀后的力学性能

对经历不同程度轴压荷载的高强混凝土试件(尺寸为100 mm SymboltB@ 100 mm SymboltB@ 300 mm)进行硫酸盐长期浸泡和干湿循环试验，并在180 d侵蚀后对其进行单轴压缩试验。分析不同侵蚀方式下，硫酸盐浓度大小及历史荷载水平对峰值应力、峰值应变、弹性模量、应力-应变曲线等的影响。结果表明：在相同历史荷载水平下，随着硫酸盐溶液浓度的增加，侵蚀方式是长期浸泡时，峰值应变先减小后增加，峰值应力、弹性模量则先增大后减小；而侵蚀方式是干湿循环条件时，随硫酸盐溶液浓度的增大，峰值应变持续增加，峰值应力、弹性模量则不断减小。在相同硫酸盐溶液浓度下，随着历史荷载的增大，长期浸泡及干湿循环侵蚀方式下，其峰值应变均增加，峰值应力及弹性模量均降低。引入叠加效应系数K来表征硫酸盐侵蚀与单轴历史荷载作用2个因素的联合交互作用,分析表明，荷载历史与硫酸盐腐蚀联合作用对混凝土的损伤起到相互促进的作用。

Mechanical Properties of High-strength Concrete Subjected to Axial Compression and Sulfate Attack

Sulfate resistance tests including long-term immersion test and dry-wet cycle test were conducted on highstrength concrete specimens (100 mm ×100 mm ×300 mm) under different axial loading.Through uniaxial compression experiments on the concrete specimens that have exposed to sulfate attack for 180 days,the effects of sulfate concentration and historical load on parameters such as peak stress,peak strain,elastic modulus and stressstrain curve were analyzed.Results revealed that under the same historical load,parameter changes in the presence of long-term immersion were different from those of dry-wet cycle.In long-term erosion,with the increase of concentration of sulfate solution,peak strain decreased firstly and then increased,whereas peak stress and elastic modulus increased firstly and then decreased.On the contrary,in dry-wet cycles,with the increase of concentration of sulfate solution,peak strain increased,whereas peak stress and elastic modulus continuously decreased.Furthermore,under a given concentration of sulfate solution,with the increase of historical load,peak strain increased whereas peak stress and elastic modulus decreased both in long-term erosion and dry-wet cycles.A superposition effect coefficient K wich describes the joint effect of sulfate attack and uniaxial historical load was introduced,and the results indicated that damage was usually promoted by the combined effect of loading history and sulfate attack.