Achieving a Lower Frictional Noise and Satisfactory Skid Resistance by Designing Surface Texture of SMA Asphalt Mixture

Abstract

Rougher surface texture on stone mastic asphalt (SMA) provides higher skid resistance, but mostly produces louder frictional noise. The objective of this paper was to design the surface texture which contributed to a lower noise and satisfactory skid resistance. Lab-mixed slabs with four aggregate gradations were compacted and cut into small test blocks, which were polished to obtain different texture levels. Frictional noise level (FNL) and British pendulum number (BPN) on unpolished slabs and polished blocks were simultaneously measured, and 3D surface textures were scanned. The relationships between surface texture and noise levels/skid resistance were analyzed. An optimal surface texture was established. The results showed that, a lower FNL and satisfactory BPN were achieved by designing surface texture, which was captured by the proposed cumulative curve of texture depth and were characterized by its parameter CR2 (cumulative ratio at 2mm of texture depth). BPNs decreased linearly with the increasing of CR2 and a minimal FNL was observed when CR2 value was between 73 and 77. These helped to build a quiet and safe SMA pavement.