Skid resistance of gap graded hot-mix asphalt with added crumb rubber

Road surface condition is a critical factor that determines road safety. The paved surface of the road should have sufficient skid resistance to enable a vehicle passing over it to accelerate and stop/brake safely and comfortably. Gap graded hot-mix asphalt is generally used as a non-structural and an impermeable layer to protect the structural layers. The hot rolled sheet (HRS) asphalt mixture has larger cavities that require more asphalt compared to other asphalt pavement types. The addition of crumb rubber (CR) to the asphalt mixture was carried out using the dry mixture method, and the resulting mixture was added to the aggregate. This study utilizes gap graded asphalt pavements containing natural asphalt from a processed product called Asbuton Retona blend 55. CR was added to the asphalt mixture in proportions of 0.5%, 1%, 1.5%, and 2%. This added material improves the performance of the asphalt mixture. The skid resistance of the paved surface layer studied herein used the British pendulum tester for pavement surface temperature variations of 25 °C, 30 °C, 35 °C, 40 °C, 45 °C, and 50 °C. Utilization of CR derived from used tire rubber powder provides the benefit of reusing waste materials that can help preserve the environment. The gap graded hot-mix asphalt with added CR and asphalt modified Asbuton Retona blend 55 has shown an improvement in the skid number. These results show that the hot-mix asphalt pavement with modified asphalt is more impermeable and provides better slip resistance.