超细粉煤灰形态对超高性能混凝土(UHPC)性能和结构的影响  

Effect of Ultrafine Fly Ash Morphology on Ultra-high Performance Concrete(UHPC)Properties and Structure

作　　者：贺雄飞 陈亚豪 张新东 朱绘美 李辉[3] HE Xiongfei;CHEN Yahao;ZHANG Xindong;ZHU Huimei;LI Hui(Key Laboratory of Intelligent Monitoring and Maintenance of Tunnel Structures in Guangdong Province,Guangzhou 511458,China;China Railway Tunnel Survey,Design and Research Institute Co.,Ltd.,Guangzhou 511458,China;School of Materials Science and Engineering,Xi an University of Architecture and Technology,Xi an 710055,China)

机构地区：[1]广东省隧道结构智能监控与维护企业重点实验室,广州511458 [2]中铁隧道勘察设计研究院有限公司,广州511458 [3]西安建筑科技大学材料科学与工程学院,西安710055

出　　处：《材料导报》2024年第S01期249-253,共5页Materials Reports

基　　金：中国中铁股份有限公司科技创新计划重大专项(2021-专项-06);中铁隧道局集团有限公司支持项目(隧研合2020-06)。

摘　　要：本工作分别以平均粒径相近但形态分别为球形和碎片状的超细粉煤灰(UFA)替代硅灰制备超高性能混凝土(UHPC),对比研究了超细粉煤灰形态对UHPC工作性能、力学性能及其中钢纤维分布的影响,并从水化产物和微观结构等方面探究了超细粉煤灰形态对UHPC性能的影响机理。结果表明:与球形UFA相比,碎片状UFA的比表面积和需水量更大、活性更高。具体表现为,用于制备UHPC时,球形UFA可明显提高UHPC的流动度,但会使钢纤维下沉,并会轻微降低UHPC的力学性能;碎片状UFA对UHPC流动度的提高作用稍小,但可提高其抗折强度,此外,碎片状UFA具有更显著的大孔填充作用,在掺加碎片状UFA的UHPC中观察不到宏观气孔缺陷。In this work,ultrafine fly ash(UFA)with similar average particle size but spherical shape and fragmental shape were used to prepare ultra-high performance concrete(UHPC)instead of silica fume.The effects of UFA morphology on UHPC performance,mechanical properties and distribution of steel fibers were studied.The influence mechanism of ultrafine fly ash on the properties of UHPC was investigated in terms of hydration products and microstructure.The results show that,compared with spherical UFA,fragmentary UFA has higher specific surface area,water demand and activity when the average particle size is similar.Therefore,when used to prepare UHPC,spherical UFA can obviously improve the fluidity of UHPC,but will make the steel fiber sink and slightly reduce the mechanical properties of UHPC.Fragmentary UFA has a little less effect on improving the fluidity of UHPC,but can improve its flexural strength.In addition,fragmentary UFA has a more significant effect on large pore filling,and no macroscopic porosity defects are observed in UHPC.

关 键 词：超高性能混凝土 超细粉煤灰 形态 工作性能 力学性能 结构 

分 类 号：TU528.31[建筑科学—建筑技术科学]