Avoiding & mitigating alkali-aggregate reaction (AAR) in concrete structures

避免

• 批准号: 506199-2016
• 负责人: MorettiSanchez, LeandroFrancisco
• 金额: $ 1.75万
• 依托单位: University of Ottawa
• 依托单位国家: 加拿大
• 项目类别: Collaborative Research and Development Grants
• 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=679562
• 关键词: Avoiding; mitigating; alkali; aggregate; reaction

Alkali-aggregate reaction (AAR) is one of the main processes affecting the durability of concrete infrastructure in Canada and worldwide. Over the years, several approaches and recommendations, including a comprehensive variety of laboratory test procedures, have been developed around the world to assess the potential alkali-reactivity of concrete aggregates and the effectiveness of preventive measures (e.g. control of the cement & concrete alkali content, use of supplementary cementing materials, etc.) before their use in the field. Despite some issues with some test procedures (e.g. long-term duration, alkali leaching, long-term correlation with field structures, evaluation of concrete mixtures, etc.) and the constant need for improvement in the various standards/protocols, the majority of experts agree that, in general, it is now possible to build new concrete infrastructure with minimum or even calculated/limited risk of AAR. However, there is currently no consensus about the most efficient method(s) (e.g. surface treatments for moisture control, chemical treatments, strengthening, stress relief, etc.) that should be implemented, and when, for the rehabilitation of AAR-affected concrete structures/structural members. In this context, a number of engineers and researchers around the globe have been trying to develop appraisal techniques and tools that are capable of either halting/mitigating further AAR development in service or at least appraising the current damage degree (diagnosis) and the potential of future distress (prognosis) of affected aging structures, both essential steps in selecting efficient rehabilitation methods and optimum application periods for critical aging infrastructure affected by AAR. In this context, this research project, in collaboration with Kryton, aims to evaluate existing commercial products and develop new product(s) for preventing and/or mitigating (i.e. physically, chemically or both) concrete deterioration caused by AAR in its initial, moderate and advanced phases. The scientific benefit of this CRD is very clear through the evaluation/development of current/new products for avoiding & mitigating AAR in the field. Moreover, Kryton will benefit from the collaboration and exchange with uOttawa researchers to appraise, develop and implement new products to the Canadian and global civil engineering market.

碱骨料反应（AAR）是影响加拿大和全球混凝土基础设施耐久性的主要过程之一。多年来，世界各地已经开发了多种方法和建议，包括各种全面的实验室测试程序，以评估混凝土骨料的潜在碱反应性以及预防措施的有效性（例如控制水泥和混凝土碱含量） 、使用辅助胶凝材料等）在现场使用之前。尽管某些测试程序存在一些问题（例如长期持续时间、碱浸出、与现场结构的长期相关性、混凝土混合物的评估等）以及各种标准/协议不断改进的需要，但大多数专家同意，一般来说，现在可以以最小甚至计算/有限的 AAR 风险建造新的混凝土基础设施。然而，目前对于修复受 AAR 影响的混凝土应采用的最有效方法（例如控制水分的表面处理、化学处理、强化、应力消除等）以及何时实施尚未达成共识。结构/结构构件。在此背景下，全球许多工程师和研究人员一直在尝试开发评估技术和工具，这些技术和工具能够阻止/减轻服役中 AAR 的进一步发展，或者至少评估当前的损坏程度（诊断）和潜在的损坏程度。受影响的老化结构的未来困境（预后），这都是选择有效修复方法的重要步骤，也是受 AAR 影响的关键老化基础设施的最佳使用期。在此背景下，该研究项目与 Kryton 合作，旨在评估现有的商业产品并开发新产品，以预防和/或减轻（即物理、化学或两者兼而有之）由 AAR 在其初始、中度阶段引起的混凝土劣化。和高级阶段。通过评估/开发当前/新产品以避免和减轻现场 AAR，该 CRD 的科学效益非常明显。此外，Kryton 还将受益于与渥太华大学研究人员的合作和交流，为加拿大和全球土木工​​程市场评估、开发和实施新产品。