A FIELD TRIAL OF WATERPROOFING SYSTEMS FOR CONCRETE BRIDGE DECKS

A wide range of waterproofing systems considered suitable by manufacturers for concrete bridge decks have been laid under experimentally controlled conditions on a concrete slab, then overlaid with hot asphaltic surfacings. These surfacings were removed and the effects of hot asphalt, bond, durability and waterproofing integrity of the membranes monitored over a three year period. Many of the systems, including some of those with a Roads and Bridges certificate for use, were found to be unsuitable or ineffective. Severe damage was often caused during the laying of the base course asphalt due to penetration of the hot aggregate into the membrane. The use of a sand carpet to protect membranes overcame this problem, but the interface bond between membrane and sand carpet was weaker than that for base course road surfacing materials. Where membranes were punctured or leaked, water transmission was much greater where there was poor bond between the concrete and the membrane. Resinous primers gave a better bond to the concrete than their bituminous counterparts.(A) For the covering abstract of the conference see IRRD 839047. (Author/TRRL)