Thermal and Bonding Behavior of Synthetic Thin Pavements for Concrete Bridge Decks

Road pavements for concrete bridge decks have the task to transmit vehicular loads, avoiding specific problems of sliding, debonding, rutting and potholes. Nowadays, the increasing vehicular loads and the traffic growth are producing new challenges for deck waterproofing covers, especially under severe environmental conditions. The research proposes an experimental investigation to evaluate the performance of different kinds of waterproofing and directly carriageway synthetic overlays for concrete deck. Epoxy-polyurethane and methacrylate resins, polymeric primers and high-performance aggregates were combined to constitute different multi-layer structures to be compared with a conventional thin asphalt pavement for bridge deck. Collaboration between concrete deck and covering layers was assessed through thermal contraction-expansion trials. Pull-off strength tests were executed to account the bonding behavior of the waterproofing layers under various conditions (after freeze-thaw, with deicing salts, in presence of pre-cracked concrete supports, with moisture). Mainly, synthetic overlays, rather than thin pavements, demonstrated good performance, even if some concerns were identified about the thermal collaboration of the materials. The most promising results in terms of thermal coefficients and adhesive bond were ensured by an overlay produced with the methacrylate resins and fractions of bauxite aggregate.