摘要
为研究不同pH值硫酸钠溶液侵蚀作用下水泥砂浆断裂特性,开展了水泥砂浆材料力学试验、三点弯曲切口梁断裂试验和微观测试,结合侵蚀后试件物理力学性能、表观形态和细观结构特征,揭示不同pH值硫酸钠溶液侵蚀下水泥砂浆断裂韧度演化规律.结果表明,不同pH值硫酸钠溶液侵蚀下砂浆试件物理力学性能、断裂性能和微观结构演变过程均有所差异;当侵蚀溶液pH值为7和3时,试件起裂韧度和失稳断裂韧度随侵蚀时间先增大后减小,侵蚀180d到达峰值,270d后分别劣化了58.4%和41.2%;pH值为1时,试件两断裂参数随侵蚀时间持续劣化,240d后分别劣化了92.1%和79.9%.随溶液pH值减小,砂浆逐渐由发生溶出性侵蚀和硫酸盐侵蚀转化为酸性侵蚀主导的复合侵蚀,侵蚀劣化效应增强;相同侵蚀溶液下,试件断裂参数与抗拉强度线性相关,起裂韧度劣化幅度明显大于失稳断裂韧度.
In order to study the fracture characteristics of cement mortar under the attack of sodium sulfate solution with different pH values,the material mechanics tests,the fracture tests of three-point bending notched beam and microscopic tests of cement mortar were conducted.Combined with the physical and mechanical properties,apparent morphology and microstructure characteristics of the eroded specimens,the evolution mechanism of fracture toughness of cement mortar under sulfate attack with different pH values was revealed.The results show that the evolution process of physical and mechanical properties,fracture properties and microstructure of the mortar specimens under sulfate attack with different pH values are different.When the pH values of the erosion solution are 7 and 3,the initial fracture toughness and fracture toughness of the specimens increase first and then decrease with the erosion time.After 180 days of erosion,the two fracture parameters reach their peak values,and after 270 days,they deteriorate by 58.4%and 41.2%,respectively.When the pH value of the solution is 1,the two fracture parameters of the specimens continue to deteriorate with the erosion time,and after 240 days,they deteriorate by 92.1%and 79.9%,respectively.As the pH value of the solution decreases,the mortar gradually changes from dissolution erosion and sulfate erosion to composite erosion dominated by acid erosion,and the erosion deterioration effect is enhanced.Under the same erosion solution,the fracture parameters of the specimens are linearly correlated with their tensile strength.The deterioration of the initial fracture toughness of the specimen is significantly greater than that of the unstable fracture toughness.
作者
甘磊
沈振中
徐力群
刘得潭
GAN Lei;SHEN Zhenzhong;XU Liqun;LIU Detan(State Key Laboratory of Hydrology-Water Resources and Hydraulic Engineering,Hohai University,Nanjing,210098,China;College of Water Conservancy and Hydropower Engineering,Hohai University,Nanjing,210098,China)
出处
《应用基础与工程科学学报》
EI
CSCD
北大核心
2023年第3期690-702,共13页
Journal of Basic Science and Engineering
基金
国家自然科学基金项目(51609073)
江苏省自然科学基金项目(BK20201312)
关键词
水泥砂浆
硫酸钠溶液
pH值
物理力学特性
断裂韧度
微观结构
劣化
cement mortar
sodium sulfate solution
pH value
physical and mechanical properties
fracture toughness
microstructure
deterioration
作者简介
甘磊(1987—),男,教授.E-mail:ganlei2015@hhu.edu.cn;通信作者:徐力群(1983—),男,副教授.E-mail:xuliqun6.2@163.com
