杨宏天,李北星,易浩,金德川

• 1:武汉理工大学硅酸盐建筑材料国家重点实验室

摘要(Abstract)：

【目的】为了探究再生微粉代粉煤灰作矿物掺合料制备再生混凝土的可行性，【方法】对比研究了原状再生微粉、磨细再生微粉以胶凝材料总质量的10%、20%、30%替代粉煤灰制备的再生混凝土的工作性、强度和耐久性，并测试了再生微粉对胶凝材料浆体水化热和混凝土孔结构的影响。【结果】结果显示：随着原状再生微粉掺量的增加，混凝土达到等坍落度所需减水剂掺量增加，再生微粉磨细后可以缓解这一不利影响；原状再生微粉掺量的增加，降低了混凝土强度、增加了吸水率和电通量，且抗折强度的降低幅度大于抗压强度，磨细再生微粉替代率在20%以内时，对混凝土上述性能的影响不大。随着再生微粉掺量的增加和细度的增大，胶凝材料的早期水化放热速率逐步加快，水化放热量不同程度提高，其中磨细再生微粉掺量20%时，胶凝材料的7 d水化热提高幅度最大，达9.5%;原状再生微粉替代率30%以内，或磨细再生微粉替代率为10%或30%时，水化热增幅均在5%以内。磨细再生微粉掺量20%以内有利于混凝土孔隙率的降低和孔径的细化，但当再生微粉掺量达30%时，混凝土中的孔径200 nm以上的多害孔显著增加，孔径发生了粗化。【结论】结果表明：再生微粉应磨细后使用，磨细再生微粉代粉煤灰配制对水化热温升有严格要求的混凝土时，其适宜掺量为胶凝材料的10%,配制普通混凝土时其掺量最高可达20%。

关键词(KeyWords)： 再生微粉;粉煤灰;混凝土;水化热;孔结构

Abstract:

Keywords:

基金项目(Foundation): 国家重点研发计划课题(2020YFC1909904)

作者(Author): 杨宏天,李北星,易浩,金德川

DOI: 10.13928/j.cnki.wrahe.2023.08.018

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