微掺碳纳米管泡沫混凝土特性演化规律研究  

Study on the Characteristic Evolution Law of Micro-Dosage Carbon Nanotube Foamed Concrete

作　　者：高航 GAO Hang(China Railway 19^(th)Bureau Group Third Engineering Co.Ltd.,Shenyang Liaoning 110000,China)

机构地区：[1]中铁十九局集团第三工程有限公司,辽宁沈阳110000

出　　处：《铁道建筑技术》2023年第2期23-26,99,共5页Railway Construction Technology

基　　金：国家自然科学基金项目(51974146、52174078)。

摘　　要：为研究以微掺量碳纳米管(CNTs)纤维制备的CNTs泡沫混凝土(CNTFC)作为隧道卸压吸能材料的适用性,联合单轴加载和数字散斑采集技术,通过室内试验研究不同CNTs纤维掺量对CNTFC试件受载变形特征影响规律,并结合SEM-EDS测试技术分析CNTFC试样强度形成机理;针对不同CNTs掺入率CNTFC试件应力-应变、位移场、最大剪应变场演化规律进行研究。结果表明:CNTFC材料极限应变远大于普通混凝土脆性材料的极限应变,随CNTs掺量增加CNTFC试件峰后在保持一定变形条件下仍能提供较高抗压阻力,该特性是围岩支护卸压材料必有性能;提出CNTFC试件变形局部化启动条件分为应变判定条件和应力判定条件,应变判定条件为达到峰值应变的86.7%,应力判定条件为达到峰值应力的80.1%,以应变条件作为CNTFC试件变形局部化启动判定条件更为合理;微观测试结果表明水泥基材料水化产物与CNTs纤维所形成的复杂网络结构使CNTFC试件宏观力学性能得以提高。In order to study the applicability of CNTs foamed concrete(CNTFC) prepared with micro-dosage carbon nanotube(CNTs) fibers as a tunnel pressure relief and energy absorbing material, this paper combined with uniaxial loading and digital speckle collection technology and make a study on the influence of different CNTs fiber content on the deformation characteristics of CNTFC materials under load through laboratory tests. The strength formation mechanism of CNTFC specimens was analyzed by SEM-EDS. The evolution law of stress-strain, displacement field and maximum shear strain field of CNTFC specimens with different CNTs incorporation rates was studied. The results show that the ultimate strain of CNTFC material is much larger than that of brittle materials such as ordinary concrete. With the increase of CNTs content, the CNTFC specimens can still provide higher compressive resistance under certain deformation conditions after the peak is maintained. This characteristic is the necessary performance of the surrounding rock support pressure relief material;it is proposed that the localized initiation conditions of CNTFC specimens deformation are divided into strain judgment conditions and stress judgment conditions. The strain judgment condition is 86.7% of the peak strain, and the stress judgment condition is 80.1% of the peak stress. It is suggested that using the strain condition as the judging condition is more reasonable for the localized deformation of the CNTFC specimens. Micro test shows that the hydration products of cement-based materials form a complex network structure with CNTs fibers, which improves the macro mechanical properties of CNTFC specimens.

关 键 词：碳纳米管 泡沫混凝土 数字散斑 受载变形 微观测试 室内试验 

分 类 号：TU528.01[建筑科学—建筑技术科学] TU502.6