The UK has a number of concrete roadways where the pavement remains structurally sound but the original surface has become worn, giving rise to a loss of skid resistance and texture depth. A number of treatments have been examined to reinstate the skid resistance properties, including asphalt overlays, hydro-blasting, high friction surfacing, longitudinal diamond grinding, transverse grinding, bush hammering, shot blasting, conventional and double helix extra fine milling. Three treatments: bush hammering, shot blasting, conventional and double helix extra fine milling, were carried out on sites in the south of England. This paper publishes details of the design and engineering analyses and the results of monitoring texture depth and skid resistance over two years. The fine milling was found to be the preferred treatment on the basis of the initial skid resistance performance, cost and productivity (eight lanes over five miles within 15 nights) and additional lengths of this treatment were carried out. After two years, the texture depth on all the sections has remained stable throughout the monitoring period. The sections subject to fine milling are performing well, with higher low speed skid resistance after treatment and high speed friction within the range expected on concrete surfaces. The other treatments result in lower texture depth and perform less well, both in their skid resistance and high speed friction. Some isolated lengths in the sections treated with fine milling remained untreated and show lower skid resistance; this requires close quality control in future applications.
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