Selection Criteria of Polyurethane Resins to Seal Concrete Joints in Underwater Road Tunnels in the Montreal Area

Polyurethane resins are widely used in infrastructure repair technologies, particularly to stop water inflow in underground tunnels. However, the longevity of these chemical grouts is not well documented, as their application is relatively new. This is particularly true in Canada, and especially in the Montréal area, where tunnel walls are subject to many freezing and thawing cycles in one year, initiating some debonding and water inflow followed by ice formation. This presentation is dedicated to the characterization of various polyurethane resins under such environmental conditions. Special laboratory tests have been developed to measure the bonding strength and shrinkage of these resins injected into cracked concrete or in improperly sealed expansion joints. These traction tests and cyclic expansion/contraction tests illustrated the major role of environmental conditions (humidity and temperature) on the effectiveness of these resins. Several well-documented applications have been conducted during the rehabilitation of two major road tunnels in Montréal. The most effective imperviousness was obtained with a semi-rigid hydrophobic polyurethane resin, but it is also very important to specify how to prepare the fissures and how to inject these resins.