多因素耦合作用下海工高性能混凝土劣化过程研究

High performance marine concrete deterioration process under multi-factor coupling action

通过试验模拟研究了在不同环境条件下海工混凝土的抗压强度、轴拉性能、水溶性氯离子含量变化过程。结果表明:在低水胶比条件下,长龄期标养试件抗压强度高于干湿循环试件,而高水胶比条件下,标养试件强度低于干湿循环试件;无论是在干湿循环还是在标养条件下,试件的轴拉强度与极限拉伸值均随时间的增加而增加,试件的轴拉弹模随着养护时间的增加而降低;按照现行的试验方法,在腐蚀溶液与干湿循环耦合条件下,试验龄期1年内,试件的力学性能基本无变化,为提高试验效率,降低试验成本,现行的试验规程应用于高性能混凝土需重新修订;当试件承受超过50%极限拉应力时,混凝土表面开始产生微裂缝,加速腐蚀溶液的侵蚀速度;当构件承受的拉应力小于50%极限拉应力时,混凝土构件基本无破坏,腐蚀溶液对混凝土不存在加速破坏现象。

The changing process of marine concrete performances including compressive strength, axial tensile behavior, water - solubility chloride ion content were tested under different conditions. Results show that under the condition of low water binder ratio long term standard curing specimens＇compressive strength are higher than specimens which are cured under the dry - wet cycle.Bnt when the water binder ratio is higher,results are reverse.Nomatter in the condition of standard curing or in dry - wet cycle, specimens＇tensile strength and ultimate tension increase with the time ,but the tensile modulus of specimen is decrease with the time.According to the current tes- ting method and at the age of 1 year, the mechanical properties of the specimens have no change with the multi - factor combined effects of wet and dry cycles in corrosion solution.In order to improve test efficiency and reduce test cost,the current test specification for high performance concrete should be revised.When the specimen bears more than 50% ultimate tensile stress,concrete surface pro- duces many micro cracks, which accelerate the corrosion rate of erosion solution. When concrete component is subjected to tensile stress is less than 50% of maximum tensile stress, the concrete component has no damage and the corrosion solution does not accelerate the damage of concrete.