'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: 2019
• 资助国家: 加拿大
• 起止时间: 2019-01-01 至 2020-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=679612
• 关键词: Crack; free; smart; self; sealing

NECESSITY***Infrastructure 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 PROGRAM***In 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.******BENEFITS***This 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.**

必要性***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了 80 亿美元，导致结构寿命缩短的一个关键因素是建筑材料的过早老化。新建和修复项目的基础设施创新需求和耐用材料迫切需要使用先进的非接触式无损评估 (NDE) 技术来监测我们的基础设施的健康状况，以预测结构的安全剩余寿命。******建议的项目***近年来，人们对使用碳纳米管（CNT）增强水泥基材料进行了研究，虽然传统上是在宏观尺度上表征水泥基复合材料，但为了充分了解碳纳米管的影响，还必须在宏观尺度上进行研究。拟议的计划将重点研究纳米尺度的特性，以开发“纳米级混合纤维增强水泥复合材料”（NHyFRCC），碳纳米管和微碳纤维的混合组合将允许降低。维多利亚大学世界上放大率最高的电子全息显微镜之一将用于研究增强材料的分散和微观结构改性。******水泥材料的早期行为影响很大。将使用 NHyFRCC 发明的专利技术对其长期耐久性以及早期收缩开裂潜力进行研究。申请人。*****将研究 NHyFRCC 在压缩、拉伸和弯曲方面的本构特性，并将开发一个数学模型来定义电阻抗降低（由于碳增强材料的存在）与尺寸变化之间的关系。所开发的材料将作为薄层覆盖在维多利亚大学现有的仪器测试台上，以模拟桥面上两种材料的现场性能（包括脱粘），并使用传感器进行远程监控。监测和 NDE 技术包括加拿大的一款便携式激光扫描测振仪 (LSV)。******优点***该研究计划将增进对纳米级增强水泥材料行为的基本了解，预计将成为纳米级增强水泥材料的基础。 LSV 是建筑行业的下一个重大突破，具有广泛的适用性，具有无裂缝、自密封且具有传感功能的薄覆盖层，这将改变我们评估高素质人员（包括毕业生和专业人员）状况的方式。本科生将获得与基础设施管理各个方面相关的专门培训和宝贵经验。**