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为了研究寒冷地区带缝工作的聚乙烯醇纤维增强水泥基复合材料(PVA-ECC)的抗(盐)冻性能,采用快冻法研究带有2种不同预制裂缝高度的PVA-ECC分别在淡水和氯盐中的抗冻性能;分析对比不同预制裂缝高度、粉煤灰掺量和冻融循环次数对PVA-ECC抗冻性能的影响;并对各个因素的影响机理进行了分析。研究结果表明:PVA-ECC在氯盐环境中的抗冻性能较差,表层剥落严重;粉煤灰掺量对PVA-ECC抗冻性能影响较大,粉煤灰掺量越高,PVA-ECC抗冻性越差;水冻时,125次冻融循环之前缝高对质量损失影响较大,缝高越大,质量损失率越大,125次冻融循环后,缝高对质量损失的影响不明显;无论是盐冻还是水冻,整个冻融循环过程中,缝高越大,动弹性模量降低得越多,抗冻性越差。
In order to study the freezing resistance of polyvinyl alcohol fiber reinforced cement-based composites (PVA-ECC) with stitches in cold areas, the fast freezing method was used to study the PVA-ECC with two different prefabricated crack heights in fresh water And chloride salt. The effects of different prefabricated crack height, fly ash content and freeze-thaw cycles on the freeze-thaw resistance of PVA-ECC were analyzed. The influence mechanism of each factor was also analyzed. The results show that PVA-ECC has poor frost resistance and severe spalling in the chloride environment. The content of fly ash greatly affects the frost resistance of PVA-ECC. The higher the content of fly ash, the higher the PVA-ECC The higher the seam height is, the greater the mass loss rate is. After 125 freeze-thaw cycles, the effect of seam height on mass loss Not obvious; whether salt or frozen water, the whole freeze-thaw cycle, the greater the seam height, the lower the dynamic elastic modulus, the worse the frost resistance.