Interface Shear Performance between Porous Polyurethane Mixture and Asphalt Sublayer

Abstract

This paper aims to study interface shear performance between porous polyurethane mixture (PPM) and asphalt mixture with different adhesive materials. Polyurethane, epoxy resin, and SBS (styrene–butadiene–styrene) modified asphalt were selected as adhesive materials to fabricate composite specimens. The interface shear strength and shear fatigue life of composite specimen was measured using inclined shear test. The research results emphasizes that it is necessary to apply adhesive material to the interface between PPM and asphalt mixture, since the untreated interface shear strength is smaller than the ones between two asphalt mixtures. The interface shear strength is affected by the thickness of adhesive layer, temperature, and freezing–thaw condition. In general, the greatest interface shear strength was achieved by using epoxy resin followed by polyurethane and then SBS modified asphalt at 25 °C as the adhesive layer thickness is the same. However, the interface shear strengths of composite specimen with three adhesive materials are similar to each other at high and low temperatures (60 °C and −18 °C) or after freezing–thaw cycles. On the other hand, the composite specimen with epoxy resin as adhesive material has the longest fatigue life; while the SBS modified asphalt has the least fatigue life at 25 °C. The research findings can help select the appropriate adhesive materials and increase the durability and service life of pavement when PPM is used as road surface layer for safety and noise reduction.