Highway Research Record

VI. RESEARCH WORK DONE IN ACADEMIC INSTITUTIONS RELATED TO THESIS WORK
A. HIGHWAY PLANNING, MANAGEMENT, PERFORMANCE EVALUATION AND INSTRUMENTATION
Overlay Alternatives on Flexible Pavement – A case study

Date of Start:December 2004
Shri G. S. Institute of Technology & Science, Indore (R)

Scope and Objective
(i) To study the present traffic condition on the existing Indore Ring Road
(ii) To investigate the structural adequacy of the existing flexible pavement using Benkelman Beam Deflections
(iii) To propose and design the different types of the overlays on the structural adequate pavement
(iv) Cost Evaluation of different overlays and their comparison

Methodology
In this dissetation work the rebound deflection measurements are taken using Benkelman beam apparatus and design of different overlays has been done. The Flexible Overlay design has been carried out as per IRC:81-1997. The Rigid Overlay has been done in the same procedure as for the new pavement given by IRC:58-2002. In the recent years a newer technology similar to rigid overlay with lower thickness has emerged known as Ultra-Thin White topping (UTW). This UTW has been designed based on “Development of Design Guide for UTW”.

Findings and Conclusions
The flexible overlay on section-1 is 206 mm and on section-2 is 220 mm, these thickness are normally assumed to be high. This suggests that the pavement suffered a regular periodic maintenance. The rigid overlay thickness is 32 cm and the UTW overlay thickness is 10.2 cm. The above values suggest that the UTW thickness is very less when compared to flexible and rigid overlay.
The LCCA for 12% discount rate suggests that flexible overlay becomes costlier then rigid and UTW overlay, due to its heavy maintenance inflow over the life period. The rigid overlay and UTW has less cost and the UTW is cheaper amongst all. Hence the best alternative is to provide UTW which is highly economical and beneficial.