摘要
主要考虑混凝土的水灰比、新老混凝土浇筑间隔期和结合面处理方式的影响,基于超声无损检测和劈裂抗拉强度试验对结合面的黏结性能开展研究,并与整体混凝土进行对比。结果表明:超声波速受水灰比影响最大,受界面处理方式影响很小;超声波速相比首波波幅,可以更好地反映新老混凝土界面的黏结质量。水灰比越小,整体混凝土劈裂破坏后的界面处裂纹更少,界面更为完整,而新老混凝土劈裂后界面破损的程度更大;随着浇筑间隔期的增加,新老混凝土劈裂后的界面破坏越平整。整体试件的劈裂抗拉强度总是大于新老混凝土试件,随着水灰比的减小,两者的劈裂抗拉强度都在增加。涂抹水泥净浆的新老混凝土界面在劈裂后相对纯凿毛界面能够保持较为平整的界面状态,且劈裂抗拉强度也相对较大;纯凿毛的界面,劈裂后的状态与凿毛后的状态保持大致相同。
To study the bonding properties of old and new concrete,variables including water-cement ratio,casting interval between old and new concrete,and interface treatments were considered.Based on the ultrasonic non-destructive test and splitting tensile test,the bonding properties of the new-to-old concrete interface were investigated and compared with the monolithic concrete.The results indicated that ultrasonic wave velocity is the most influenced by the water-cement ratio,with minimal impact from the interface treatment.Compared to the first wave amplitude,ultrasonic wave velocity can better reflect the bonding quality of interface.A lower water-cement ratio results in fewer cracks at the interface in the monolithic concrete under tensile splitting tests,making the interface more intact,while the extent of interface damage after splitting of the old and new concrete is greater.With an increase in casting interval,the interface damage after the splitting of new and old concrete becomes flatter.The split tensile strength of the monolithic specimen is always greater than that of the old and new concrete specimens.As the water-cement ratio decreases,the splitting tensile strength of both types of specimens increases.The rough interface applied with cement paste,after undergoing splitting tensile tests,exhibits a relatively smoother interface compared to the artificially chiseled interface.Furthermore,the splitting tensile strength of this interface is relatively higher.The state of the artificially chiseled interface after splitting remains largely similar to its post-chiseled interface.
作者
张菊辉
盘奕彤
云辉
ZHANG Juhui;PAN Yitong;YUN Hui(College of Environment and Architecture,University of Shanghai for Science and Technology,Shanghai 200093,China)
出处
《混凝土》
2025年第8期90-95,103,共7页
Concrete
基金
国家自然科学基金(51408359)。
关键词
新老混凝土
劈裂抗拉
超声无损检测
黏结性能
new and old concrete
splitting tensile
ultrasonic non-destructive test
bonding strength
作者简介
第一作者:张菊辉(1981-),女,博士,副教授,研究方向:混凝土耐久性。联系地址:上海市杨浦区军工路516号上海理工大学环境与建筑学院207室(200093)。联系电话:13916437640。
