无机盐工业
主管:中海油天津化工研究设计院有限公司
主办:中海油天津化工研究设计院有限公司
   中海油炼油化工科学研究院(北京)有限公司
   中国化工学会无机酸碱盐专业委员会
ISSN 1006-4990 CN 12-1069/TQ

无机盐工业 ›› 2024, Vol. 56 ›› Issue (9): 75-81.doi: 10.19964/j.issn.1006-4990.2023-0472

• 研究与开发 • 上一篇    下一篇

再生细骨料对超高性能混凝土的力学与自收缩性能影响

刘慈军1(), 吴子杨2, 程书凯2,3(), 陈旭勇2,3   

  1. 1.宁波高等级公路建设管理中心,浙江 宁波 315099
    2.武汉工程大学土木工程与建筑学院,湖北 武汉 430073
    3.武汉工程大学绿色土木工程材料与结构湖北省工程研究中心,湖北 武汉 430073
  • 收稿日期:2023-09-28 出版日期:2024-09-10 发布日期:2024-09-26
  • 通讯作者: 程书凯(1989— ),男,硕士生导师,博士,研究方向为先进水泥基材料;E-mail:734157817@qq.com
  • 作者简介:刘慈军(1971— ),男,博士,主要从事超高性能混凝土桥梁结构的研究;E-mail:172294127@qq.com
  • 基金资助:
    国家自然科学基金资助项目(52208286);湖北省自然科学基金资助项目(2022CFB672);武汉知识创新专项-曙光计划项目(2022020801020362)

Effect of recycled fine aggregate on mechanical properties and autogenous shrinkage of ultra-high performance concrete

LIU Cijun1(), WU Ziyang2, CHENG Shukai2,3(), CHEN Xuyong2,3   

  1. 1.Ningbo High-grade Highway Construction Management Center,Ningbo 315099,China
    2.Civil Engineering and Architecture,Wuhan Institute of Technology,Wuhan 430073,China
    3.Hubei Provincial Engineering Research Center for Green;Civil Engineering Materials and Structures,Wuhan Institute of Technology,Wuhan 430073,China
  • Received:2023-09-28 Published:2024-09-10 Online:2024-09-26

摘要:

将再生细骨料应用于超高性能混凝土(UHPC)不仅能降低成本,还可实现建筑垃圾资源化利用。采用预湿状态再生细骨料制备UHPC,探究再生细骨料的粒径(0.6~<1.18 mm和1.18~2.36 mm)和不同掺量(10%、20%、30%和40%,均为体积分数)对UHPC的工作性能、力学性能、体积稳定性、抗氯离子渗透性能的影响,利用热重分析(TG-DTG)、显微硬度、压汞仪(MIP)和扫描电子显微镜(SEM)等测试方法揭示其影响机理。结果表明,再生细骨料的粒径和掺量是影响UHPC力学性能和体积稳定性的关键因素。随着预湿再生细骨料掺量增大,UHPC的流动性和自收缩值逐渐减小,但其抗压强度表现出先增大后降低的趋势,其中掺入20%预湿再生细骨料(粒径为1.18~2.36 mm)制备的UHPC性能更优,与未掺再生细骨料UHPC相比,其28 d抗压强度提升7.0%,7 d自收缩值降低了78.8%;预湿再生细骨料内养护效应有助于降低UHPC内部自干燥进程、提高水化反应程度、优化界面过度区组成结构、减少有害孔和多害孔数量。

关键词: 超高性能混凝土, 再生细骨料, 力学性能, 自收缩, 孔结构

Abstract:

The application of recycled fine aggregate to ultra-high performance concrete(UHPC) not only reduces its cost,but also realizes the resource utilization of construction waste.UHPC was prepared by pre-wet recycled fine aggregate(RFA).The effects of particle sizes(0.6~<1.18 mm and 1.18~2.36 mm) and replacement rates(10%,20%,30% and 40% of volume fraction) of pre-wetted treatment RFA on working performance,mechanical properties,volume stability and chloride ion penetration resistance of UHPC were investigated.The mechanism was revealed by microhardness,TG-DTG,MIP and SEM.The results showed that the particle size and content of recycled fine aggregate were the key factors that determined the workability,mechanical properties and shrinkage properties of UHPC.With the increase of RFA content,the fluidity and autougenous shrinking of UHPC were decreased gradually.But its compressive strength showed a trend of increasing firstly and then decreasing,among which UHPC prepared with 20% pre-wetted recycled fine aggregate(particle size of 1.18~2.36 mm) showed better performance.Compared with the control group,the 28 days compressive strength was increased by 7.0%,while the autougenous shrinking was decreased by 78.8%.The pre-wetted RFA released water into the UHPC matrix,reduced the internal self-drying process,and improved the degree of hydration reaction,which optimized the interface composition structure,and thus refined the internal pores of the matrix.

Key words: ultra-high performance concrete, recycled fine aggregate, mechanical properties, autougenous shrinkage, pore structure

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