Rehabilitation of Low Volume Flexible Pavements by White Topping-a Case Study

Abstract

In India the nature of overlay treatment in the name of maintenance on flexible pavements is generally Hot Mix Asphalt (HMA) as this technology is in for many years. Lack of interest in selecting different resurfacing alternative is seen in road contractors because of ease in construction of HMA overlay and experience gained by them in construction of HMA overlay. Whitetopping can be a very interesting resurfacing technique for existing asphalt pavements when rutting is the major distress on pavement surface. In the present work an attempt is made to evaluate the structural and functional condition of existing flexible pavements and provide a cost effective rehabilitation solution. A network of six urban roads coming under Tumkur Municipality is selected an extensive field, laboratory investigation, pavement analysis and design of rehabilitation alternative has been carried out. The field work consists of road inventory, traffic studies, MERLIN and BBD studies. PCI is computed based on selected distress parameters (Rut, Patch, Pothole, Cracks). In addition, IRI, BI and characteristics pavement deflections are computed from MERLIN and BBD surveys. Based on PCI, IRI, BI and deflection values pavement rehabilitation measures are considered. The summary of overall condition assessment on functional and structural evaluation in majority of the cases has resulted in 'resurfacing'. In the present study an attempt has been made to design whitetopping section and asphalt overlay as a minor rehabilitation alternative for the in-service flexible pavements. The whitetopping design has resulted in 5 thin whitetopping sections and 1 ultra-thin whitetopping section. Strengthening by asphalt overlay has resulted in different overlay thicknesses for selected roads. Finally cost comparison between whitetopping and asphalt overlay reveals that for majority of selected roads whitetopping proves to be a cost effective rehabilitation solution than the asphalt overlay.