Performance Evaluation of Low Volume Flexible Pavements - A Case Study

In a developing country like India, periodic evaluation of low volume urban roads is required to prioritize the order of maintenance and rehabilitation of the road network. This paper presents a typical case study of an urban road network of Tumkur City, Karnataka, India. Six roads stretches of the selected road network were investigated for traffic volume, functional and structural condition in terms of California bearing ratio (CBR) value of the subgrade soil, rebound deflection from Benkelman Beam Deflection(BBD) survey, International Roughness Index(IRI) using Machine for Evaluating Roughness using Low-cost Instrumentation(MERLIN) and condition rating based on extent of cracking, patching, rutting and potholes. The structural condition is evaluated using KENLAYER software to obtain the critical strains. Two of the existing measures of pavement condition are used to evaluate the pavement condition and to decide the order of maintenance priority for the selected road network. It is found that the two methods namely Pavement Condition Index (PCI) and Maintenance Priority Index (MPI) do not yield a satisfactory ranking of the maintenance requirement. A more comprehensive prioritization index called Modified Maintenance Priority Index (MMPI) is proposed and is found to give realistic ranking of the maintenance priority requirement of the selected road network.