碳纳米管改性固废混凝土的制备及其工作性能研究  

Preparation and performance study ofcarbon nanotube modified solid waste concrete

作　　者：刘京红 冯鹏龙 杨晋荣 张彦 张凌博 尚伟 LIU Jinghong;FENG Penglong;YANG Jinrong;ZHANG Yan;ZHANG Lingbo;SHANG Wei(School of Civil Engineering,Tianjin Chengjian University,Tianjin,300384,China;China Railway Construction Group Co.,Ltd.,Beijing 100040,China)

机构地区：[1]天津城建大学土木工程学院,天津300384 [2]中铁建设集团有限公司,北京100040

出　　处：《功能材料》2025年第1期1223-1229,共7页Journal of Functional Materials

基　　金：天津市自然科学基金项目(21JCYBJC00730,23JCQNJC00850)。

摘　　要：以固废混凝土为再生粗骨料,采用50%的铁尾矿砂取代天然河砂,选取多壁碳纳米管(CNTs)为纳米增强材料,制备出碳纳米管改性铁尾矿砂再生骨料混凝土。通过力学性能、吸水率、SEM(电子扫描显微镜)等表征测试,探究碳纳米管掺量、再生粗骨料替代率对混凝土性能的影响,建立了固废混凝土抗压强度预测公式并验证了该公式的可行性。分析结果表明,制备固废混凝土时掺加适量CNTs,混凝土力学强度呈抛物线型先增后减的规律;通过SEM试验发现,适量CNTs能够改变混凝土的微观界面结构,加快早期水化进程,同时优化其孔隙分布,进而形成更高密度的基体。为改善固废混凝土性能和固废资源化利用提供了新途径。Using solid waste concrete with primary strength of C30 as recycled coarse aggregate,50%iron tail sand was used to replace natural river sand,and multi-walled carbon nanotubes(CNTs)were selected as nano-reinforced materials to prepare carbon nanotube modified iron tail sand reclaimed aggregate concrete.Through mechanical properties,water absorption,SEM(electron scanning microscope)and other characterization tests,the effects of carbon nanotube content and recycled coarse aggregate replacement rate on concrete properties were investigated.The test results show that CNTs were incorporated directly into the concrete mixing process,resulting in concrete with compressive,flexural,and splitting tensile strengths that exhibited a parabolic trend,initially increasing and then decreasing as they cure over time.When the amount of CNTs added 01%,the flexural strength and compressive strength of recycled concrete containing iron tailings reach the relatively highest values.The splitting tensile strength of recycled concrete containing iron tailings reache the highest value when 0.15%of CNTs added.The SEM test showed that appropriate CNTs could change the micro-interface structure of concrete,accelerate the early hydration process,and reduce the slump degree of concrete mixture.CNTs,as the nucleation site of cement hydration reaction,increased the reaction rate of cement in the hydration process.Combined with mesh filling and bridging,the toughness of the concrete was significantly improved,while the pore distribution optimized to form a higher density matrix.When using carbon nanotubes to enhance recycled coarse aggregates,the content of carbon nanotubes should not exceed 0.20%(mass fraction).Excessive CNTs content would cause the matrix to reunite,forming loose weak areas,which in the deterioration of the performance of the concrete.The prediction formula of compressive strength of solid waste concrete was established,and the feasibility of the formula was verified,which provided different methods for the numerical simulati

关 键 词：再生粗骨料 工作性能 微观形貌 碳纳米管 铁尾矿砂 

分 类 号：TU528[建筑科学—建筑技术科学]