Guidelines development for sustainable use of reactive/marginal/recycled aggregates in concrete construction

骨料组成和性能在很大程度上影响混凝土的力学性能和耐久性能。优质材料的短缺、新建筑的压力越来越大以及可持续发展做法的应用，将导致在混凝土建筑中更多地使用具有有害/边际性质或由回收/工业过程产生的集料。另一方面，S在1950-1970年代建造的大量混凝土结构由于不同的病理原因而处于令人震惊的状况，包括有害的骨料反应。由于公营部门财政紧绌，加上社会需求不断增加，大量老化的搭建物需要进行修补工程，以延长其使用年限。因此，我的研究目的是通过解决混凝土基础设施中有害的骨料反应引起的混凝土耐久性问题来促进可持续性。*在研究主题A中，将进行调查，以1)更好地了解有害骨料反应所涉及的机制，2)改进混凝土骨料的质量控制测试，以及3)制定更好的指导方针/标准，以设计使用这种骨料的长期结构。将从现有的现场测试样品中提取岩芯，这些样品由反应性聚集体制成，有预防措施和不采取预防措施，储存在北美和欧洲不同的暴露地点。然后，将对岩芯进行全面的微观结构/机械表征。将使用活性再生混凝土骨料和含硫化物骨料制造更多的现场测试试件，以进行长期的现场性能监测；同时，混凝土试件将浇注，并接受常规和新的实验室测试程序，以改善现场和实验室性能的相关性。*在研究主题B中，将优化现场检查方案和实验室方法，以量化受有害骨料反应影响的混凝土基础设施(特别是大体积混凝土)的当前状况和未来恶化的可能性。将检查以前为缓解劣化目的而处理过的各种结构，并就延长受ASR影响的结构的使用寿命的最佳措施提出建议。*拟议研究计划的优势和独创性在于：可获得用于验证混凝土集料质量控制新测试程序的长期现场性能数据、国内/国际范围内强大的合作者网络、成功实施指南和标准研究的历史，以及研究团队最有利的工作/培训环境，包括广泛的HQP。**

Aggregate composition and properties largely affect the mechanical and durability performance of concrete. The shortage in quality materials, the increasing pressure for new construction and the application of sustainable development practices will result in an increased use, in concrete construction, of aggregates with deleterious/marginal properties or resulting from recycling/industrial processes. On the other hand, a large number of concrete structures built in the 1950-1970's are in alarming conditions resulting from different pathologies, including deleterious aggregate reactions. Because of the tight financial situation in the public sector and ever-increasing social needs, a large number of ageing structures will require remedial work for extending their service life. The objective of my research is thus to contribute to sustainability by resolving concrete durability issues resulting from deleterious aggregate reactions in concrete infrastructure. ***In the Research Theme A, investigations will be carried out to 1) better understand the mechanisms involved in deleterious aggregate reactions, 2) improve QC tests for concrete aggregates, and 3) develop better guidelines/standards to design long-lasting structures with such aggregates. Cores will be extracted from existing field test specimens made with reactive aggregates, with and without preventive measures, and that were stored on different exposure sites across North America and Europe. The cores will then be subjected to full microstructural/mechanical characterization. Additional field test specimens will be manufactured with reactive recycled concrete aggregates and sulphide-bearing aggregates, with/without supplementary cementing materials, for long-term field performance monitoring; in parallel, concrete specimens will be cast and subjected to conventional and new laboratory test procedures for improving field and laboratory performance correlations. ***In Research Theme B, field inspection protocols and laboratory methodologies will be optimized for quantifying the current condition and the potential for future deterioration of concrete infrastructure (notably mass concrete) affected by deleterious aggregate reactions. Various structures that were previously treated for deterioration mitigation purposes will be inspected and recommendations developed on the best measures to apply to extend the service life of ASR-affected structures. ***The strength and originality of the proposed research program relate on the availability of long-term field performance data for validating new test procedures for QC of concrete aggregates, a strong network of collaborators on the national/international scenes, an history of successful implementation of the research into guidelines & standards, and most favourable work/training environment for the research team, including a wide array of HQP. **