Durability Evaluation of Single-Component Polyurethane-Bonded Porous Mixtures

Abstract

Pavement service and antiaging performance of single-component polyurethane-bonded porous mixtures (PPMs) were studied. The influence of the adhesive–aggregate ratio on PPM volumetric properties and pavement service performance was analyzed by testing PPM air voids, water permeability coefficients, dynamic and Marshall stabilities, Cantabro loss rates, −10°C bending-failure strains, and the British pendulum number (BPN20). Four-point bending fatigue tests conducted after ultraviolet (UV)-accelerated aging were used to characterize PPM antiaging performance. The results showed that PPM air voids and connected air voids were negatively linearly correlated with the adhesive–aggregate ratio. PPM and an open-graded friction course (OGFC) asphalt mixture, with identical connected air voids, did not have significantly different water permeability coefficients, indicating that polyurethane- or asphalt-film connected-pore surfaces did not significantly impact water permeability. PPM dynamic and Marshall stabilities, Cantabro loss rates, and −10°C bending-failure strains were much better than those of the OGFC asphalt mixture. These pavement service performance indicators increased, whereas BPN20 decreased with increasing adhesive–aggregate ratio. When the adhesive–aggregate ratio reached 5%–6%, there was an inflection point in the trend of the pavement service performance, which can be used as a criterion to determine the optimal adhesive content. After 1 simulated year of aging, changes in the PPM initial bending-stiffness modulus DSini and the antifatigue damageability DSini were significantly better than those of the OGFC. UV aging nonlinearly influenced PPM DSini and Ds. The influence of UV aging on DSini and DSini initially were large and, small and gradually decreased and increased, respectively.