Importance of pavement rehabilitation design in Bangladesh

The Roads and Highways Department of Bangladesh manages its road assets with a cost-effective maintenance programme using the HDM-4 model. However, it has been observed that some of the thin maintenance overlay treatments have not been functioning well in recent years for a sample of roads. Repeated overlays were suggested by the HDM-4 within 2 years for these roads. As a result, the existing structural strengths of these roads were checked by deflection data using a Benkelman beam, and strengthening overlay (thick overlay) thicknesses were derived using the Asphalt Institute rehabilitation design chart. An example to determine the required thickness of overlay using the Asphalt Institute rehabilitation design chart is presented herein. It was checked for consistency using the American Association of State Highway and Transportation Officials equation. Finally, treatment intervention criteria were chosen using the HDM-4 to determine the optimum thicknesses of strengthening overlay for structurally weak roads in Bangladesh.