干湿循环下废弃纤维再生混凝土氯离子传输性能

Chloride Transport Performance of Waste Fiber Recycled Concrete under Dry-Wet Cycles

研究了干湿循环次数、再生粗骨料取代率、废弃纤维体积分数对废弃纤维再生混凝土氯离子传输性能的影响,并分析了氯离子的传输机理.结果表明:干湿循环下,随着再生粗骨料取代率的增加,再生混凝土抗氯离子侵蚀能力降低,掺入废弃纤维能够提高其抗氯离子侵蚀能力;干湿循环条件对不同再生粗骨料取代率试件中自由氯离子含量影响更显著,且自由氯离子含量随侵蚀深度增加先增大后减小;自由氯离子含量与总氯离子含量呈线性相关,氯离子结合能力系数的精确度为0.001;在实际工程的耐久性能设计中,可忽略再生粗骨料取代率和废弃纤维体积分数对氯离子结合能力的影响.

The effects of dry‑wet cycles,replacement rate of recycled coarse aggregates and volume fraction of waste fiber on chloride transport performance of waste fiber recycled concrete were studied,and the chloride transport mechanism was analyzed.The results show that with the increase of replacement rate of recycled coarse aggregate,the chloride erosion resistance of recycled concrete becomes smaller under dry‑wet cycles.The addition of waste fiber can improve the resistance of chloride erosion of the recycled concrete.The dry‑wet cycled condition show a more significant effect on the content of free chloride ion with different recycled aggregate replacement rates.Under the dry‑wet cycles,the content of free chloride increases first and then decreases with the increase of the erosion depth.There is a linear correlation between free and total chloride content,and the accuracy of coefficient representing chloride binding capacity is 0.001.In the actual engineering durability design,the effects of replacement rate of recycled coarse aggregate and the volume fraction of waste fiber on chloride binding capacity can be ignored.