'Crack-free' and smart `self-sealing' composites with improved microstructure, early-age properties, and durability

“无裂纹”和智能“自密封”复合材料具有改进的微观结构、早期性能和耐用性

• 批准号: RGPIN-2016-05219
• 负责人: Gupta, Rishi
• 金额: $ 1.75万
• 依托单位: University of Victoria
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2022
• 资助国家: 加拿大
• 起止时间: 2022-01-01 至 2023-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=760185
• 关键词: Crack; free; smart; self; sealing

NECESSITYInfrastructure in Canada and around the world is aging rapidly. According to estimates, the deficit to repair Canadian bridges alone has exceeded $8 billion. A key factor responsible for the reduced life of structures is premature deterioration of construction materials. Our aging infrastructure needs innovative and durable materials for new and rehabilitation projects. There is a dire need to monitor health of our infrastructure using advanced non-contact Non-destructive Evaluation (NDE) techniques to predict safe remaining life of structures.PROPOSED PROGRAMIn recent years, use of Carbon Nanotubes (CNTs) to reinforce cement-based materials has been investigated. While cementitious composites are traditionally characterized at the macroscale, for full understanding of the influence of CNTs, studies must also be conducted at the nanoscale. The proposed program will focus on studying characteristics at the nanoscale to develop “Nano Scale Hybrid Fiber Reinforced Cement Composites” (NHyFRCC). Hybrid combinations of CNTs and micro carbon fibers will allow lowering the cost while addressing issues faced with mixing and dispersing this combination. One of world's highest magnification electron holography microscope at UVic will be utilized to study the reinforcement dispersion and microstructure modification.Early-age behavior of cementitious materials greatly influences its long-term durability, hence early-age shrinkage cracking potential will be studied. This self-sealing' and crack arresting ability of NHyFRCC will be quantified using a patented technique invented by the applicant.Constitutive properties of NHyFRCC in compression, tension, and flexure will be investigated. A mathematical model defining the relationship between the reduced electrical impedance (due to presence of carbon reinforcement) and dimension change will be developed to quantify the sensing capabilities. The developed material will be applied as a thin overlay on an existing instrumented test bench at UVic to simulate field conditions on a bridge deck. Field performance of both materials (including debonding) from the substrate will be monitored using sensors, remote monitoring, and NDE techniques including one of its kind portable Laser Scanning Vibrometer (LSV) in Canada.BENEFITSThis research program will advance the fundamental understanding about the behavior of cementitious materials reinforced at the nanoscale. NHyFRCC is expected to be the next major breakthrough in the construction industry with wide applicability as a thin overlay that is crack-free, self-sealing and has sensing capabilities. The use of LSV will change the way we assess condition of our aging infrastructure. Highly qualified personnel including graduate and undergraduate students will gain specialized training and valuable experience related to various aspects of infrastructure management.

加拿大和世界各地的基础设施正在迅速老化。据估计，仅修复加拿大桥梁的赤字就超过80亿美元。造成建筑物寿命缩短的一个关键因素是建筑材料的过早劣化。我们老化的基础设施需要创新和耐用的材料用于新的和修复项目。利用先进的非接触式非破坏性评估（NDE）技术来预测建筑物的安全剩余寿命，对基础设施的健康状况进行监测是一项迫切的需求。虽然传统上水泥基复合材料的特点是在宏观尺度上，充分了解碳纳米管的影响，研究也必须在纳米尺度上进行。该计划将专注于研究纳米级的特性，以开发“纳米级混合纤维增强水泥复合材料”（NHyFRCC）。CNT和微碳纤维的混合组合将允许降低成本，同时解决混合和分散这种组合所面临的问题。利用UVic世界上最高放大倍数的电子全息显微镜，研究水泥基材料的早期性能对水泥基材料的长期耐久性有很大影响，因此将研究水泥基材料的早期收缩开裂潜力。将使用申请人发明的专利技术来量化NHyFRCC的这种自密封和止裂能力。将研究NHyFRCC在压缩、拉伸和弯曲时的本构特性。一个数学模型定义之间的关系，降低电阻抗（由于碳增强的存在）和尺寸变化将开发量化的传感能力。开发的材料将作为一个薄的覆盖在现有的仪器测试台在UVic模拟现场条件下的桥面。这两种材料（包括脱粘）从基板的现场性能将使用传感器，远程监控和无损检测技术，包括其在加拿大的便携式激光扫描测振仪（LSV）之一进行监测。NHyFRCC有望成为建筑行业的下一个重大突破，作为一种无裂缝、自密封和具有传感能力的薄覆盖层，具有广泛的适用性。LSV的使用将改变我们评估老化基础设施状况的方式。包括研究生和本科生在内的高素质人员将获得与基础设施管理各方面有关的专门培训和宝贵经验。