中南大学学报（自然科学版）2023，Vol.54Issue(12)：4860-4869,10.DOI:10.11817/j.issn.1672-7207.2023.12.023
盐冻交替作用下混凝土强度与细观孔结构关系
Relationship between strength and fine-scale pore structure of concrete under effect of salt-freezing alternation
摘要
Abstract
To explore the quantitative correlation between macroscopic strength and fine pore structure parameters of concrete under the alternating effects of sulphate solution erosion and freeze-thaw cycle(salt freezing),the salt freezing alternating tests,mechanical property tests and pore structure analysis were conducted.Firstly,the alternating tests with different mass fraction of sulphate and the number of freeze-thaw cycles were designed.Secondly,the evolution of the compressive strength,tensile strength,grayscale histogram,pore size distribution,porosity,and evolution patterns of fractal dimension under the influence of salt freezing were analyzed.Finally,the quantitative relationships between concrete porosity,pore fractal dimension and strengths were established.The results show that the macroscopic strength of concrete under salt-freezing is closely related with the evolution of fine-scale pore structure.The compressive strength and splitting tensile strength of concrete gradually decrease with the increase of salt-freezing cycles.Compared with the sulfate with mass fraction of 3%and 6%,the freeze-thaw action of the sulfate with mass fraction of 9%deteriorates concrete more severely,and the compressive and splitting tensile strengths decrease by 45.5%and 47.5%,respectively,at 8 salt-freezing cycles.With the increase of salt-freezing cycles,the grayness value of concrete CT images and pore fractal dimension gradually decrease,while the porosity gradually increases.The mean grayness value and pore fractal dimension decrease by 13.82%and 6.06%,respectively,compared with the initial state at 8 salt-freezing cycles,and the porosity increases to 7.3%.The evolution models of fine-scale pore structure and macroscopic strength under the effect of salt-freezing alternation are well correlated,and the R2 is greater than 0.887.关键词
硫酸盐侵蚀/冻融循环/交替作用/混凝土强度/孔结构/演化规律Key words
sulfate erosion/freeze-thaw cycle/alternating action/concrete strength/pore structure/evolution law分类
建筑与水利引用本文复制引用
甘磊,冯先伟,沈振中,陈官运..盐冻交替作用下混凝土强度与细观孔结构关系[J].中南大学学报（自然科学版）,2023,54(12):4860-4869,10.基金项目
国家自然科学基金资助项目(52379123,52179130) （52379123,52179130）
江苏省自然科学基金资助项目(BK20201312)(Projects(52379123,52179130)supported by the National Natural Science Foundation of China （BK20201312）
Project(BK20201312)supported by the Natural Science Foundation of Jiangsu Province) （BK20201312）
