Dealing with critical aging infrastructures: challenges and research needs

民用基础设施对于社会至关重要，它连接国家的企业、社区和人民，推动经济发展并提高人类的生活质量。一方面，加拿大和世界范围内 1960 年代至 1980 年代建造的许多老化结构都呈现出明显的损坏迹象，这些迹象是由许多有害的损坏机制造成的，例如碱骨料反应 (AAR)、延迟钙矾石形成 (DEF)、硫酸盐侵蚀、钢材腐蚀、冷冻和解冻循环等。为了保证其设计使用寿命内的性能，甚至延长其预期寿命，工程师需要高效可靠的工具来关联机械性能和物理完整性的降低。以及受影响材料（诊断）对其结构后果的耐久性。这些信息对于确定进一步恶化的可能性（预后）和选择及时有效的管理措施至关重要。另一方面，考虑到对可持续和有弹性的基础设施的需求，以及未来几十年保护自然资源的压力，必须使用生态高效/环境友好的材料建造新结构，同时优化工业过程和拆除已达到预期使用寿命的基础设施产生的材料的回收。因此，当前研究计划的目标在于开发A）优化的创新工具，用于老化混凝土基础设施的状况评估和未来行为预测； B）了解材料损伤与受各种病理影响的混凝土构件/结构的结构性能/行为之间相互作用的技术知识； C）针对不良、老化基础设施的时间相关性能模型，允许对此类结构采取可靠和及时的管理行动； D) 生态高效/环境友好的高性能混凝土配合比设计，以实现建筑业的可持续和弹性发展。拟议研究的结果将有助于开发测试程序、模型和行为法则，以及可靠的管理建议/实践，以延长新混凝土结构的设计寿命或老化混凝土结构的使用寿命。

Civil infrastructure is critical for society, connecting the nation's businesses, communities and people, driving the economy and improving the quality of life of human beings. On one hand, numerous aging structures built in the 1960's to 1980's in Canada and worldwide present clear signs of distress caused by numerous harmful damage mechanisms such as alkali-aggregate reaction (AAR), delayed ettringite formation (DEF), sulfate attack, steel corrosion, freezing and thawing cycles, etc. To guarantee performance over their designed service lives, or even to extend their expected life spans, engineers need efficient and reliable tools for correlating the reductions in mechanical properties, physical integrity and durability of affected materials (diagnosis) to their structural consequences. This information is critical in determining the potential for further deterioration (prognosis) and selecting timely and efficient management actions. On the other hand, considering the need for sustainable and resilient infrastructure, as well as the pressure to preserve natural resources for the decades to come, it is essential that new structures are built with eco-efficient/environmentally friendly materials, while optimizing the recycling of materials resulting from industrial processes and demolition of infrastructure having reached their expected service life. Therefore, the objectives of the current research program lie in the development of A) optimized innovative tools for condition assessment and prediction of future behaviour of aging concrete infrastructure; B) technical knowledge for understanding the interactions between the material's distress and the structural performance/behaviour of concrete members/structures affected by various pathologies; C) time-dependent performance models for distressed, aging infrastructure allowing for reliable and timely management actions for such structures; and D) eco-efficient/environmentally friendly high performance concrete mix designs for the sustainable and resilient development of the construction industry. The results of the proposed research will contribute to the development of testing procedures, models and behavioural laws as well as reliable management recommendations/practices for either extending the design life of new concrete constructions or the service lives of aging concrete structures.