Pavement thickness, surface evenness and construction practice

The structural performance and the riding quality of a road are strongly influenced by the accurate and uniform laying of the pavement materials to the appropriate design thickness. The report describes an investigation into the effectiveness of level-control procedures currently used in road construction to achieve the required thicknesses and surface regularity. Measurements of surface profile and thickness of pavement were made, during construction, on 38 randomly selected 100-metre lengths from two flexible and three rigid roads. Analysis of the measurements showed that the mean layer thicknesses were generally at or near the required thickness but that layer thickness varied considerably along the test lengths, particularly for the concrete pavements. On flexible roads, the results showed that the profiles of the lower layers influenced the evenness of the finished surface. On rigid construction the evenness of the finished surfaces was found to be independent of the profile of the sub-base. It is suggested that better methods of controlling the laying of pavement materials would improve the uniformity of performance of both flexible and rigid roads and would improve the riding quality of flexible roads. (A)