粉煤灰对高强混凝土抗盐冻性能的影响研究

Study on effects of fly ash on the salt freezing resistance of high strength concrete

研究了高强混凝土在浓度为4%NaCl溶液中冻融循环后的性能退化,分析了粉煤灰掺量对高强混凝土盐冻环境下耐久性的影响规律。结果表明:随着粉煤灰掺量的增加,混凝土表面损伤越来越明显。随着冻融循环次数的上升,试样的质量损失率逐渐上升,且上升趋势越来越明显。在相同冻融循环次数下,随着粉煤灰掺量的增加,试样的质量损失率逐渐上升。粉煤灰掺量越高,混凝土的相对动弹性模量下降越明显。随着粉煤灰掺量的增加,混凝土的初始抗压强度逐渐下降。在同一循环次数下,粉煤灰掺量越高,混凝土的抗压强度下降越明显。根据试验结果提出了粉煤灰混凝土在盐冻环境下的质量损失模型,与试验结果吻合良好。

The performance degradation of high-strength concrete after freeze-thaw cycles in 4%NaCl solution was studied,and the effects of fly ash content on durability of high-strength concrete under salt freezing environment were analyzed.Results showed that with the increase of fly ash content,the surface damage of concrete was more and more obvious.With the increase of the number of freeze-thaw cycles,the mass loss rate of samples increases gradually,and the increase trend was becoming more and more obvious.Under the same number of freezing and thawing cycles,the mass loss rate of samples increased with the increase of fly ash content.The higher fly ash content was,the more obvious the relative dynamic elastic modulus of concrete decreased.With the increase of fly ash content,the initial compressive strength of concrete gradually decreases.Under the same cycle times,the higher fly ash content was,the more obvious compressive strength of concrete decreased.According to the test results,the mass loss equation of fly ash concrete under salt freezing environment was put forward,which is in good agreement with the test results.