摘要
针对高寒、高盐地区混凝土材料损伤劣化的问题,开展不同质量分数硫酸盐溶液侵蚀和冻融循环作用下混凝土侵蚀及力学特性试验,分析混凝土试件表观形态及质量变化、抗压强度、劈裂抗拉强度和相对动弹性模量等的演化过程,揭示硫酸盐侵蚀和冻融循环作用下混凝土损伤演化规律.结果表明:在硫酸盐侵蚀初期,混凝土内部硫酸盐与水泥水化物生成侵蚀物,可填充混凝土初始缝隙,随侵蚀物积累,试件逐渐产生微裂缝和贯穿型裂缝,其基本力学性能呈先增长后下降的趋势;硫酸盐侵蚀与冻融循环交替作用下混凝土力学性能呈下降趋势,硫酸钠溶液在侵蚀初期对冻融损害起抑制作用,随侵蚀历时增加,硫酸盐侵蚀与冻融循环相互促进,混凝土损伤演化过程可分为加速损伤、缓慢损伤和快速损伤三个阶段;盐冻交替循环8次后的混凝土试件抗压和抗拉强度较单硫酸盐侵蚀情况降低约40%,混凝土在盐冻循环作用下的损伤程度较单一硫酸盐侵蚀作用更严重.
In view of the damage and deterioration of concrete materials in high-cold and high-salt areas,the erosion experiments and material mechanics tests of hydraulic concrete under sulfate solution erosion with different mass concentrations and freeze-thaw cycles were carried out to analyze the evolution process of apparent form and mass change,compressive strength,splitting tensile strength and relative dynamic elastic modulus of concrete specimens.Results show that in the initial stage of sulfate attack,the erosion material is formed by the reaction of sulfate and cement hydrate inside the concrete,which can fill the initial cracks of the concrete.With the accumulation of the erosion material,the specimens gradually produce micro-cracks and penetrative cracks,whose basic mechanical properties show a trend of increasing first and then decreasing.The mechanical properties of concrete show a downward trend under the alternating action of sulfate attack and freeze-thaw cycle,and the freeze-thaw damage is inhibited by sodium sulfate solution at the initial stage of erosion.With the increase of erosion duration,sulfate attack and freeze-thaw cycle promote each other,and concrete damage evolution process can be divided into three stages,which are accelerated damage,slow damage and rapid damage.The compressive strength and tensile strength of concrete specimens after 8 times of salt-freezing alternate cycle are reduced by about 40%compared with that of single sulfate attack,and the damage degree of concrete under the action of salt-freezing cycle is more serious than that of single sulfate attack.
作者
甘磊
刘源
沈振中
陈官运
GAN Lei;LIU Yuan;SHEN Zhenzhong;CHEN Guanyun(College of Water Conservancy and Hydropower Engineering,Hohai University,Nanjing 210098,China)
出处
《华中科技大学学报（自然科学版）》
EI
CAS
CSCD
北大核心
2023年第11期134-141,共8页
Journal of Huazhong University of Science and Technology(Natural Science Edition)
基金
国家自然科学基金资助项目(52379123,52179130)
江苏省自然科学基金资助项目(BK20201312)。
关键词
水工混凝土
硫酸盐侵蚀
冻融循环
力学性能
损伤演化
hydraulic concrete
sulfate attack
freeze-thaw cycle
mechanical property
damage evolution
