Performance Investigation and Internal-Structure Analysis of Polyurethane Bonded Mixture on Highway Steel Bridge

Abstract

This study investigated the feasibility of applying a polyurethane-bonded mixture (PUM) on the pavement overlay for construction or maintenance. Styrene butadiene styrene (SBS) asphalt and epoxy asphalt, the two most common and widely adopted mix designs for highway steel bridge pavement, were selected for a comparative study. First, the performance evaluations and failure analysis of the asphalt mixture and PUM were investigated comprehensively, in terms of low-temperature property, rutting, fatigue, and freeze-thaw resistance. The results showed that the dynamic stability of PUM was over 30,000 cycles/mm and fatigue life was over one million cycles under 800 με. The tensile strength ratio (TSR) value was higher than 90%, which also indicated an excellent freeze-thaw resistance. Then, bond and shear strengths between the steel plate and the mixture were evaluated for the interlayer of the steel bridge pavement structure. X-ray CT scan analysis was adopted to visualize the internal structure of various mixtures, and the average void diameter of PUM was 0.569 mm. Finally, a statistical analysis was conducted for Kendall consistency and Grey correlation. This research established that PUM is a cost-effective and long-lasting solution for pavement overlay on highway steel-bridge.