摘要
为揭示直剪作用下早龄期再生混凝土的破坏机理与力学性能,将取代率和养护龄期作为研究参数,制作了27个立方体试件进行剪切试验,观察了试件断面形态,获得了试件的剪力-剪切位移曲线,分析了取代率和龄期对直剪强度、峰值位移和剪切模量的影响规律。结果表明:龄期t=3 d时,主要为骨料与水泥基体之间的黏结破坏;t=7 d、28 d时,主要为界面黏结破坏和骨料剪断破坏2种破坏形式;t<7 d时,取代率越大,抗剪强度越大,峰值位移越小;当t=28 d时,取代率越大,抗剪强度越小,峰值位移越大;相较于t=3 d的抗剪强度,t=7 d、28 d的抗剪强度提高幅度分别为20.70%和75.40%。龄期较短或较长时,取代率对损伤影响均较大,t=7 d时,取代率对损伤影响最小。最后,提出了不同龄期下再生混凝土直剪强度计算公式。
Twenty-seven cube specimens were made for shear test with substitution rate and curing age as study parameters to reveal the failure mechanism and mechanical properties of early recycled concrete under direct shear action.The section shape of the specimen was observed;the shear forcedisplacement curve of the specimen was obtained;and the effects of substitution rate and age on direct shear strength,peak displacement and shear modulus were analyzed.The results show that when t=3 d,the damage is mainly caused by the bond between aggregate and cement matrix;when t=7 d or 28 d,the failure modes are mainly interface bond failure and aggregate shear failure.When t<7 d,the shear strength increases and the peak displacement decreases with the increase of substitution rate.When t=28 d,the shear strength decreases and the peak displacement increases with the increase of substitution rate.The shear strength improves by 20.70%and 75.40%respectively when t=7 d or 28 d.The effect of substitution rate on damage is great when the age is short or long,and the effect of substitution rate on damage is minimal when the age is 7 d.Finally,the formulas for calculating the direct shear strength of recycled concrete at different ages are put forward.
作者
姜锐
张绍松
陈宇良
黄芳玮
徐鸿飞
JIANG Rui;ZHANG Shaosong;CHEN Yuliang;HUANG Fangwei;XU Hongfei(School of Architecture and Civil Engineering,Guangxi University of Science and Technology,Liuzhou 545006,China;Liuzhou Orient Engineering Rubber Products Co.,Ltd.,Liuzhou 545005,China)
出处
《广西科技大学学报》
2022年第4期16-22,43,共8页
Journal of Guangxi University of Science and Technology
基金
国家自然科学基金项目(51908141)
广西自然科学基金项目(2019GXNSFBA245030)
广西科技大学研究生教育创新计划项目(GKYC202131)资助。
关键词
早龄期
再生混凝土
直剪作用
破坏形态
力学性能
损伤机理
early age
recycled concrete
direct shear
failure mode
mechanical properties
damage mechanism
