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

“无裂纹”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: 2016
• 资助国家: 加拿大
• 起止时间: 2016-01-01 至 2017-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=615569
• 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衰老。据估计，仅维修加拿大桥梁的辩方超过了80亿加元。导致结构寿命降低的关键因素是建筑材料的过早确定。我们的老龄化基础设施需要创新和耐用的材料，用于新的和康复项目。直接需要使用先进的非接触性非破坏性评估（NDE）技术来监测基础设施的健康，以预测结构的剩余寿命。 建议的计划 近年来，已经研究了使用碳纳米管（CNT）来增强水泥基材料。尽管传统上在宏观上表征了胶结成分，但要充分理解CNT的影响，但还必须在纳米级进行研究。拟议的计划将着重于研究纳米级的特征，以开发“纳米量表杂交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此组合所面临的问题。 UVIC上世界上最高的电子全息显微镜之一将用于研究增强分散和微观结构修饰。 水泥材料的早期行为极大地影响了其长期耐用性，因此将研究早期收缩率开裂潜力。 NHYFRCC的这种“自密封”和破解能力将使用适用的专利技术进行量化。 NHYFRCC在压缩，张力和挠曲方面的构成性能将进行投资。定义减少电阻抗（由于碳增强的存在）和尺寸变化之间关系的数学模型将开发以量化灵敏度能力。开发的材料将在UVIC的现有仪器测试工作台上用作薄覆盖层，以模拟桥甲板上的田间条件。将使用传感器，远程监控和NDE技术来监视两种材料（包括脱皮）的现场性能（包括剥离）。 好处 该研究计划将提高人们对在纳米级增强的胶结材料行为的基本理解。 NHYFRCC预计将是建筑行业的下一个重大突破，其适用性广泛，是薄薄的覆盖层，无裂纹，自我密封并且具有敏感性。 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个方面有关的专业培训和宝贵的经验。