Project 1.1: Studies on the Fracture and Damage Behaviour of Cold Joints and Interfaces

Concrete remains the backbone of modern infrastructure, yet its durability is increasingly challenged by climate-induced stresses, environmental degradation, and fatigue-related failures. Repair and rehabilitation of concrete structures such as dams, bridges, and buildings often introduce interfaces between old and new materials, which are typically weaker and prone to cracking. Cold joints in mass concrete, inevitable in dam construction, act as bi-material interfaces and present critical sites for crack initiation and propagation. This study aims to investigate the fracture behaviour of such interfaces, focusing on Mode I and Mode II fracture toughness, fracture energy, and scaling effects using large-sized specimens with realistic aggregates. Experimental programs will employ advanced techniques including acoustic emission, digital imaging, and servo-controlled loading to capture microstructural changes under static, cyclic, and combined water–seismic loading. Analytical and computational models based on fracture and damage mechanics will be developed to simulate crack propagation, assess safety margins, and design effective repair systems. The research further seeks to establish failure envelopes for mixed-mode loading, propose remedial measures such as local post-tensioning, and validate findings on selected dams. Expected contributions include improved understanding of interface mechanics, development of repair materials and methodologies, guidelines for non-destructive and destructive testing, and computational frameworks for safety assessment. The outcomes will support preventive maintenance, reduce life-cycle costs, and enhance resilience of critical infrastructures. Capacity building through training of researchers and engineers in advanced testing and rehabilitation techniques will ensure long-term impact on dam safety and sustainability.