Performance evaluation of patch repairs on historic concrete structures (PEPS): a bibliographic review of patch repair durability

Concrete repair and, more specifically, patch repair, is a complex process, which still presents challenges and results in durability issues. Durability of a patch repair is affected by many factors occurring throughout the repair process, such as diagnosis of the existing structure, design of the repair material, surface preparation, workmanship, loading, and exposure conditions [1]. Each phenomenon should be individually understood, but, for an efficient and durable repair, a holistic approach is advisable as every parameter is likely to affect several other variables in a different way [2]. This topic is abundant in the scientific literature related to contemporary concrete structures, but few are dedicated to historic concrete. All the considerations for modern buildings are relevant for concrete heritage, but additional specific requirements must be considered in order to preserve its cultural significance. The purpose of this bibliographic study is to highlight the key factors for evaluating the performance of concrete patch repair in the peculiar context of cultural heritage. Particular focus is put on compatibility issues between the repair system and the original historic material.