摘要
针对现有混凝土耐久性室内试验研究与实际结构服役状态不一致问题，试验研究了持续稳定压荷载长期作用下不同受荷水平混凝土中氯离子的输运规律，以及徐变对氯离子输运的影响。试验结果表明：持续稳定压荷载长期作用下，混凝土徐变变形随荷载水平提高而增大；混凝土渗透性开始提高的临界应力水平为0．3—0．4；混凝土的表观氯离子扩散系数随着徐变变形的增大先略有降低然后迅速增大。不同持载状态下的试验研究结果表明：持载状态对混凝土中氯离子的输运有着较大影响，应力水平高于0．4时，持续稳定荷载长期作用下徐变增大了混凝土的损伤，导致低应力水平作用下混凝土提前劣化，高应力水平下混凝土加速劣化。此外，受压混凝土超声波速的变化趋势与氯离子输运规律表现出了较好的一致性，可作为氯盐环境下混凝土耐久性能评价的检测指标。
To solve the inconsistency problem of concrete durability evaluation under different conditions of laboratory test and actual service environment, an experiment was carried out in this paper to study the chloride permeability of concrete subjected to long-term sustained compressive loads, and the influence of concrete creep on the chloride transportation. The test results show that under the condition of long-term sustained and steady compressive loads, the creep strain of concrete increases with the increase of loading level, and the threshold stress level for significant deterioration is 0.3-0.4. The chloride permeability of con- crete decreases slightly first and then increases rapidly with the increases of creep strain. The comparisons of test results under different sustained compression states show that beyond the stress level of 0.4, the accumulated creep deformation due to the action of long-term sustained and steady loading enhances the concrete damage, leading to an earlier deterioration at low stress level and accelerated the deterioration at high stress level, which indicates that long-term sustained loading has a significant effect on the chloride ions penetration. In addition, the results of ultrasonic velocity test are consistent with those of chloride ions test, which confirm that the ultrasonic pulse velocity can be used to detect or determine the chloride transportation of concrete.
出处
《水利学报》
EI
CSCD
北大核心
2015年第8期974-980,共7页
Journal of Hydraulic Engineering
基金
国家自然科学基金资助项目(51178417
51378456)
浙江省自然科学基金重点项目(LZ13E080001)
留学归国人员择优基金资助项目
浙江大学海洋交叉引导基金资助项目
关键词
压荷载
耐久性
超声波速
氯离子
徐变
compressive load
durability
ultrasonic velocity
chloride ion
creep
