The Efficiency of Waterproofing Coatings and Sealers to Mitigate ASR-Induced Expansion and Deterioration in Aging Concrete

Alkali-silica reaction (ASR) is one of the main causes of damage in aging concrete structures, resulting in microcracking, loss of material integrity, and reduced functionality. Despite its widespread occurrence, there is still no consensus on the most effective ways to mitigate or rehabilitate structures or members affected by ASR. While various waterproofing materials have shown promise, their effectiveness is limited by the continued progression of ASR and the formation of new cracks. Self-healing waterproofing materials have been introduced recently, but their performance under physicochemical distress mechanisms is poorly understood. This study aims to evaluate the ability of three types of surface treatments, silane/siloxane high-performance penetrating sealers, crystalline waterproofing coating mixtures with self-healing properties and with or without fibers, to mitigate concrete deterioration caused by ASR in its early and moderate stages. The effectiveness of these treatments in mitigating ASR is assessed using microscopic analysis. The results indicate that surface treatments alter the kinetics of ASR and that the induced expansion results in the loss of mechanical properties and microscopic features.