Reinforced concrete slabs strengthened with externally bonded carbon fibre-reinforced polymer strips under long-term environmental exposure and sustained loading. Part 1: Outdoor experiments

Abstract

Carbon fibre-reinforced polymers (CFRPs) can be used to increase the load-bearing capacity of concrete bridge deck slabs and their lateral cantilevers. In this study, experiments were performed to explore the long-term performances of loaded RC slabs strengthened on the top surface using non-prestressed and prestressed externally bonded (EB) CFRP strips. A real bridge application was simulated by applying mastic asphalt on the top surface. The effects of four years of outdoor exposure to elevated temperatures and solar radiation were considered. The results show that specimens strengthened with non-prestressed EB CFRP strips exhibit satisfactory behaviours, but a substantial increase in strain is shown in the CFRP strips over time. A slab strengthened with prestressed EB CFRP strips anchored with a so-called gradient anchorage experiences premature failure, owing to elevated temperatures and sustained loads.

Keywords

• Concrete slabs CFRP strengthening
• Temperature and sustained load long-term effects
• Prestressed composites strips using the gradient anchorage
• Concretebridges
• Viscoelastic behaviour