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

集料的组成和性能在很大程度上影响着混凝土的力学性能和耐久性能。由于优质材料短缺、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/边缘特性或来自回收/工业过程的骨料。另一方面，大量建于1950-1970年代的混凝土结构由于不同的病理学（包括有害的骨料反应）而处于令人担忧的状况。由于公营部门的财政紧绌，加上社会需求不断增加，大量老化的建筑物需要进行维修工程，以延长其使用寿命。因此，我的研究目标是通过解决混凝土基础设施中有害骨料反应导致的混凝土耐久性问题来促进可持续发展。* 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QC测试，以及3）制定更好的指导方针/标准，以设计具有此类骨料的长期结构。将从现有的现场测试样本中提取岩心，这些样本是用活性骨料制成的，有或没有预防措施，并储存在北美和欧洲的不同暴露地点。然后对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（含/不含辅助胶凝材料）制造额外的现场试验样本，用于长期现场性能监测;同时，将浇注混凝土样本，并进行常规和新的实验室试验程序，以改善现场和实验室性能相关性。* 在研究主题B中，将优化现场检查协议和实验室方法，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。将检查以前为缓解恶化而处理的各种结构，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与长期现场性能数据的可用性有关，这些数据用于验证混凝土骨料QC的新测试程序，在国家/国际舞台上强大的合作者网络，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. **