应力和氯盐环境下海工混凝土的碳化性能

Carbonation Performance of Marine Concrete under Stress and Chloride Environment

配制两种水胶比的海工高性能混凝土试件,开展了氯盐-碳化干湿循环试验以及拉应力-氯盐-碳化干湿循环试验,通过测试分析混凝土抗压强度和碳化深度,研究了应力和氯盐环境下海工混凝土的碳化性能。试验结果表明:氯盐-碳化干湿循环条件下,混凝土抗压强度呈现先增大后降低的现象,长期的碳化作用会引起抗压强度的降低;存在一个与抗压强度有关的临界碳化深度,碳化作用在达到临界碳化深度之前可以提高抗压强度,达到临界碳化深度之后则会降低抗压强度。在拉应力-氯盐-碳化干湿循环条件下,拉应力和氯离子侵蚀均会增大混凝土的碳化速度,两者同时作用时,对碳化速度的增大作用会相互叠加。

Two groups marine engineering high-performance concrete samples with different W∕B ratio were prepared.Two dry-wet cycling tests about the interactive environment with chloride ion and carbonation and the multiple environmentwith tensile stress, chloride ion and carbonation were designed. The compression strength and the carbonation depth wereanalyzed to research the carbonation performance of marine concrete under the chloride environment and stress. The resultsshow that the compression strength is increased at early period and then decreased gradually under the dry-wet cyclingcondition about chloride and carbonation; a critical carbonation depth related to the compression strength is existed,carbonation can improve the compression strength before the critical carbonation depth and reduce the compression strengthafter the critical carbonation depth. Under the dry-wet cycling condition about tensile stress, chloride and carbonation, bothtensile stress and chloride ion can increase the carbonation speed, these promotion can overlay each other.