Thiol-isocyanate chemistry for autonomous self-healing of epoxy resins

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Investigation of the fracture cracking behavior of self-healing systems by use of optical and acoustic experimental methods

Nowadays the self-healing process efficiency in loaded structural materials is evaluated by studying the damage mechanisms. Based on fracture mechanics theories, the resistance to damage and the cracking recovery can be an indication of healing performance. Experimentally, the cracking behavior is quantified by measuring the fracture energy of the material during cracking and the fracture process zone area at which the damage is expanded. In literature, damage detection at loading stage of testing and damage recovery due to healing mechanisms at the reloading stage is monitored by application of several experimental (Non-) Destructive Methods. In this study, the Fracture Process Zone (FPZ) in different heterogeneous materials (polymer and cementitious composites) is visualized in strain and deformation (crack opening-close-reopening) profiles of the crack tip area by application of Digital Image Correlation (DIC) and the fracture energy released in different stages of cracking is quantified and located by Acoustic Emission (AE). The combination of the aforementioned optical and acoustic techniques can confirm the recovery of cracked specimens in which healing mechanisms are applied

Non-destructive inspection technologies for repair assessment in materials and structures

Aging infrastructure globally faces degradation, posing risks and requiring substantial repair investment. Strategic maintenance practices are crucial for evaluating structural conditions and ensuring sustainability. The growing demands on modern materials and structures necessitate enhanced health monitoring approaches. Shifting from reactive to proactive maintenance methodologies is paramount, due to lower investment while keeping the structural performance at acceptable standards. However, quantitative assurance of repair/reinforcement/retrofit programs or self-healing effect in structures is similarly crucial for the operation of the infrastructure. Non-destructive testing (NDT) techniques, such as ultrasound, acoustic emission, and optical methods, play a vital role in assessing structural health. Through real-world case studies, the effectiveness of repair in addition to damage assessment are evaluated, encouraging a more systematic approach to monitoring structural repair efficacy. The paper intends to address the research gap in monitoring the repair effectiveness in civil structures and materials and provides valuable insights to enhance repair strategies in civil engineering.Concrete Structure