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- 混凝土与制品
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再生微粉复合胶凝体系C40混凝土的制备及性能研究
作者：杜磊1，2，郭启龙1，2，高敏1，2，马稚童1，2，华亮1，2，陈业照1，2，杨然1，2
（1.西北民族大学 土木工程学院，甘肃 兰州 730124；2.甘肃省新型建材与建筑节能重点实验室，甘肃 兰州 730124）
摘要：为了提高建筑垃圾的利用率，将再生微粉与粉煤灰按照不同质量比复掺后作为复合胶凝材料，取代部分水泥制备C40混凝土。研究了复合胶凝材料取代率、再生微粉掺量及研磨时间对C40混凝土坍落度、吸水率及抗压强度的影响规律和作用机理。结果表明，拌合物坍落度随复合胶凝材料取代率的增加而增大，随再生微粉掺量的增加而减小。取代率为10%和20%时，混凝土的抗压强度随再生微粉掺量的增加而降低，气孔率和吸水率在取代率为20%且再生微粉掺量为30%时达到最低。经过研磨的再生微粉会导致C40混凝土坍落度、气孔率和吸水率降低以及抗压强度提高。综合而言，最佳研磨时间为5 h。
关键词：再生微粉；复合胶凝材料；吸水率；抗压强度；研磨时间
中图分类号：TU528.041 文献标识码：A 文章编号：1001-702X（2022）10-0059-06
Preparation and properties of C40 concrete with composite cementitious system of recycled micro powder
DU Lei1，2，GUO Qilong1，2，GAO Min1，2，MA Zhitong1，2，HUA Liang1，2，CHEN Yezhao1，2，YANG Ran1，2
（1.College of Civil Engineering，Northwest University for Nationalities，Lanzhou 730124，China；
2.Gansu Key Laboratory of New Building Materials and Building Energy Conservation，Lanzhou 730124，China）
Abstract：In order to improve the utilization rate of construction waste，C40 concrete is prepared by mixing recycled micro powder and fly ash according to different mass ratios as composite cementitious materials，replacing part of cement. The influence rules and mechanism of composite cementitious material substitution rate，recycled micro powder content and grinding time on the slump，water absorption and compressive strength of C40 concrete are revealed. The results show that the slump increases with the increase of the replacement rate of composite cementitious materials，and decreases with the increase of the amount of recycled micro powder. When the substitution rate is 10% and 20%，the compressive strength decreases with the increase of recycled micro powder content，and the porosity and water absorption reach the lowest when the substitution rate is 20% and the recycled micro powder content is 30%. The milled recycled micro powder will reduce the slump，porosity and water absorption of C40 concrete and improve the compressive strength. In terms of comprehensive performance，the best grinding time is 5 h.
Key words：recycled micro powder，composite cementitious material，water absorption，compressive strength，grinding time