摘要
为了充分发挥纳米材料在提升再生混凝土基本性能方面的作用,分别采用SiO2,Al2O3,CaCO3和石墨烯(GNP)4种纳米材料与减水剂、水混合,经30 min超声分散后添加适量水泥制成纳米强化浆液,然后将再生骨料浸泡于浆液中30 min,筛分晾干后形成纳米强化再生骨料。对采用此种骨料制备的混凝土进行抗压性能测试和微观结构检测。结果表明:采用超声分散后的纳米浆液能够有效包裹于再生骨料的表面,使其界面过渡区的微观结构得到改善;纳米强化浆液浸泡粗骨料的方式能有效地提高再生混凝土的抗压强度,其中浸泡于0.2%纳米SiO2强化浆液、取代率为50%的纳米强化再生混凝土抗压强度最高,分别比未强化的再生混凝土和普通混凝土提高24.3%,33.1%;纳米材料填充了混凝土内的部分孔隙,提高了再生混凝土的密实度。所得结果可为再生混凝土的性能提升提供技术支持。
In order to effectively improve the basic performance of nano-materials in recycled concrete,ultrasonic technology was introduced.Four different types of nano-materials(SiO2,Al2O3,CaCO3 and GNP)were investigated respectively.Firstly,the nano-material was mixed with water reducer and water.After 30 min of ultrasonic dispersion,nano-strengthened slurry was obtained with proper amount of cement.Then the recycled aggregate was soaked in the slurry for 30 min.Finally,nano-enhanced recycled aggregate was gained after screening and drying.Compressive strength and microstructure of the recycled coarse aggregate concrete were tested.The results show that the nano-slurry after ultrasonic dispersion can effectively wrap around recycled aggregate and improve the microstructure of interface transition zone.Immersing coarse aggregate in nano-enhanced slurry can effectively increase the compressive strength of recycled coarse aggregate concrete.The compressive strength of nano-reinforced recycled concrete immersed in 0.2%nano-SiO2 reinforced slurry with 50%substitution of recycled coarse aggregate is 24.3%and 33.1%higher than unreinforced recycled concrete and ordinary concrete respectively.The nano-material fills up some original pores in the concrete and improves the compactness of the recycled concrete.The results obtained are considerably valuable for the performance improvement in recycled concrete.
作者
延永东
徐鹏飞
姚嘉诚
陆春华
袁天军
YAN Yong-dong;XU Peng-fei;YAO Jia-cheng;LU Chun-hua;YUAN Tian-jun(School of Civil Engineering and Mechanics,Jiangsu University,Zhenjiang 212013,Jiangsu,China;Third Engineering Co.Ltd of CCCC Fourth Highway Engineering Co.Ltd,Beijing 100123,China)
出处
《建筑科学与工程学报》
CAS
北大核心
2020年第5期124-131,共8页
Journal of Architecture and Civil Engineering
基金
国家自然科学基金项目(51608233,51778272,51878319)。
关键词
再生混凝土
骨料强化
纳米技术
超声分散
界面过渡区
recycled aggregate concrete
aggregate strengthening
nano-technology
ultrasonic dispersion
interfacial transition zone
