Geopolymer protective coatings for concrete

Protective coatings are being used to seal and protect the concrete surfaces. The most common coatings are based on organic matrices. Their main drawback is their inability to release vapor pressure buildup that causes damage in the concrete and delamination of the coatings. This paper deals with the performance of a new inorganic fireproof coating based on Geopolymers. The coatings, which comprise the next generation of barrier and strengthening systems, have been developed and used successfully to coat concrete and wood structural members. The coatings are less permeable than concrete thus slowing the flow of water through the weakened exterior surfaces but are not impermeable like the organic coatings. One of their advantages is that vapor pressure is released because they do not form a film. In strengthening applications, the matrices form a strong bond between the surface of the concrete and the fiber reinforcement. The results presented here focus on the durability of these fireproof coatings. Experiments were conducted both in the laboratory and in the field using bridge substructures.