Concrete and mortar deterioration and fracture: a forensic approach

混凝土和砂浆的劣化和断裂：法医方法

基本信息

批准号：
RGPIN-2020-07116
负责人：
Peterson, Karl
金额：
$ 1.89万
依托单位：
University of Toronto
依托单位国家：
加拿大
项目类别：
Discovery Grants Program - Individual
财政年份：
2021
资助国家：
加拿大
起止时间：
2021-01-01 至 2022-12-31
项目状态：
已结题

来源：
https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=741604
关键词：
Concrete mortar deterioration fracture forensic

项目摘要

Concrete and mortar deterioration and fracture: a forensic approach This research aims to improve understanding of the complex combinations of factors that lead to deterioration from a microscopic perspective, and to devise solutions for more durable concrete and mortar based infrastructure. An important focus of this effort will be to unite factors that involve artisanship, choice of materials, and environmental exposure with load-induced stresses, to better understand the development of fracture networks, through a combination of microstructural analysis, experiment, and fracture modeling. This approach requires detailed characterization of not only the mineralogy, chemistry, and distribution of the constituents within the concrete or mortar, but also detailed characterization of the fractures themselves. The research program relies on 3D and 2D imaging techniques well-suited to fracture characterization: x-ray computed tomography followed by thin sectioning and examination by optical microscopy. This combination allows for detailed crack mapping that spans both the macro and micro-level. The same samples are further interrogated under a scanning electron microscope and by indentation, allowing for micro to nano level chemical and micro mechanical exploration of cementitious and aggregate components. Together these techniques provide a thorough assessment that allows for interpretation of manifestations of concrete and mortar deterioration. This forensic approach builds on research efforts currently underway, including investigations of (1) the influence of coarse aggregate on concrete strength, (2) crack development in protective concrete coatings for pipelines, and (3) the restoration, rehabilitation, and preservation of historic masonry. The research will advance understanding of the roles binder and aggregate play under load-induced concrete fracture, the interaction of concrete fracture networks with aggressive solutions in subsurface environments, and bond strength development in restoration mortars. These outcomes will inform and improve practices around concrete and mortar mix design, and support the construction industry's efforts to meet the many challenges of maintaining and creating tomorrow's concrete and masonry based infrastructure.

混凝土和砂浆的劣化和断裂：法医方法本研究旨在从微观角度提高对导致劣化的复杂因素组合的理解，并为更耐用的混凝土和砂浆基础设施设计解决方案。这项工作的一个重要重点是将涉及工艺、材料选择和环境暴露与载荷引起的应力的因素结合起来，通过微观结构分析、实验和断裂建模的结合，更好地了解断裂网络的发展。这种方法不仅需要对混凝土或砂浆内成分的矿物学、化学和分布进行详细表征，还需要对裂缝本身进行详细表征。该研究项目依赖于非常适合断裂表征的 3D 和 2D 成像技术：X 射线计算机断层扫描，然后进行薄切片和光学显微镜检查。这种组合可以实现宏观和微观层面的详细裂纹映射。相同的样品在扫描电子显微镜下和通过压痕进行进一步研究，从而可以对水泥和骨料成分进行微米到纳米级的化学和微观机械探索。这些技术共同提供了全面的评估，可以解释混凝土和砂浆劣化的表现。这种法证方法建立在目前正在进行的研究工作的基础上，包括以下方面的调查：(1) 粗骨料对混凝土强度的影响，(2) 管道保护性混凝土涂层的裂缝发展，以及 (3) 历史遗迹的恢复、修复和保存石工。该研究将加深对粘合剂和骨料在荷载引起的混凝土断裂下所起的作用、混凝土断裂网络与地下环境中侵蚀性溶液的相互作用以及修复砂浆中粘结强度发展的理解。这些成果将为混凝土和砂浆配合比设计提供信息并改进实践，并支持建筑行业努力应对维护和创建未来混凝土和砖石基础设施的诸多挑战。