摘要
为响应国家资源可持续发展战略方针,减少对天然骨料的依赖。以建筑垃圾破碎后的黏土砖(RCBA)和旧砂浆(OMA)取代天然粗骨料,研究不同取代率对再生混凝土力学性能影响,并进行破碎界面对比及微观机理分析,其中RCBA取代率为3%、6%、9%、12%、15%;OMA取代率为5%、10%、15%。结果表明:相较于普通混凝土,随着砖和旧砂浆含量增加,再生混凝土强度呈明显降低趋势,当砖和旧砂浆总含量为30%时,抗压强度下降了45.9%,劈裂抗拉强度下降了41%,且旧砂浆对再生混凝土强度的不利影响为砖的1.75倍;拟合所得再生混凝土立方体抗压强度与劈裂抗拉强度换算式相关性较好;再生混凝土试件破坏形态和普通混凝土类似,其遭受破坏时界面破坏和非界面破坏模式往往共存,但局部材料界面组成和应力传递更加复杂,其中天然骨料-新砂浆界面过渡区(ITZ)、天然骨料-旧砂浆ITZ、旧砂浆-新砂浆ITZ、旧砂浆块-新砂浆ITZ及低强度砖和旧砂浆共同组成再生混凝土薄弱区域,受力过程中最先破坏。
In response to the national strategic policy of sustainable development of resources,reduce the dependence on natural aggregates.It replaced natural coarse aggregates with crushed clay bricks(RCBA)and old mortar(OMA)from construction waste,and studied the effect of different substitution rates on the mechanical properties of recycled concrete.The comparison of crushing interfaces and microscopic mechanism analysis are conducted,with RCBA substitution rates of 3%,6%,9%,12%,and 15%;the replacement rates of OMA are 5%,10%,and 15%.The results show that compared to ordinary concrete,the strength of recycled concrete significantly decreases with increasing brick and old mortar content.when the total content of brick and old mortar is 30%,the compressive strength decreases by 45.9%and the splitting tensile strength decreases by 41%.Moreover,the adverse effect of old mortar on the strength of recycled concrete is 1.75 times that of brick;the recycled concrete obtained by fitting the cubic compressive strength and splitting tensile strength conversion formula correlation is good;recycled concrete specimen damage morphology and ordinary concrete is similar,which suffered damage when the interface damage and non-interfacial damage modes tend to coexist,but the local material interface composition and stress transfer is more complex,in which the natural aggregate-new mortar interface transition zone(ITZ),natural aggregate-old mortar ITZ,new mortar-old mortar ITZ,old mortar block-new mortar ITZ and low-strength brick and old mortar together constitute the weak region of recycled concrete,which is the first to be damaged during the stressing process.
作者
王磊
黄朝阳
邓雪莲
彭再晓
梁林
林登辉
黄珠芹
WANG Lei;HUANG Zhaoyang;DENG Xuelian;PENG Zaixiao;LIANG Lin;LIN Denghui;HUANG Zhuqin(Guangxi Key Laboratory of Green Building Materials and Construction Industrialization,Guilin 541004,China;College of Civil Engineering,Guilin University of Technology,Guilin 541004,China;CCCC First Highway Engineering Xiamen Engineering Co.,Ltd.,Xiamen 361021,China;Guangxi MESDA Engineering Machinery Equipment Co.,Ltd.,Nanning 530022,China)
出处
《混凝土》
北大核心
2025年第10期181-187,共7页
Concrete
基金
国家重点研发计划项目课题“建筑垃圾定向分类预处理技术和装备研究与工程示范”(2019YFC1906202)
广西高校中青年科研基础能力提升项目“建筑垃圾浆骨分离及骨料再利用研究”(2024KY0276)
广西绿色建材与建筑工业化重点实验室项目(桂科能19-J-21-27)。
关键词
砖
旧砂浆
再生混凝土
力学性能
破坏机理
brick
old mortar
recycled concrete
mechanical properties
failure mechanism
