LAUSR

The depletion of natural resources forces the construction industry to explore using cleaner recycled material as replacements of virgin construction materials. A new eco-friendly chip seal pavement, in which the mineral aggregate was replaced by crumb rubber obtained from scrap tires, was investigated in this study. A total of 142 chip seal specimens were prepared and tested to investigate the impact of using recycled rubber aggregate on the chip seal's micro and macro texture and their impacts on the skid resistance. The microtexture of the new proposed recycled aggregate was examined using a high-resolution 3D digital microscope. The macrotexture of the new chip seal pavement was examined using image processing and sand patch methods. The skid resistance of the new chip seal under both ambient and elevated temperatures was then explored. Two types of emulsions, two types of asphalt cement binders, two types of mineral aggregate as well as two types of recycled crumb rubber were involved in the examined test matrix. This study concluded that the crumb rubber can be used in the chip seal as partial or full replacement of mineral aggregates. Using crumb rubber has a significant impact on improving both macrotexture and microtexture of chip seal. In addition, the low thermal conductivity of crumb rubber helped the chip seal resist elevated temperature without significant loss in skid resistance. A 3D geometrical model was then proposed to simulate the aggregate embedment so it can be used to design the required binder application rate that provides adequate embedment depth and skid resistance.