Evaluation and Rehabilitation of Composite Pavement on Motorway Network in Serbia

Abstract

In the eighties the pavements on motorway roads were built with the sub-base layer made with high strength of cement-treated aggregates. After a period of considerable fall of transit traffic and lack of maintenance ensued from the political isolation of the country, by the beginning of new century the transit traffic was returning on "arterial" road facilities in Serbia. This period was marked with extensive investments in road rehabilitation. It was required to prepare the model for pavement existing conditions assessment for about 450 km motorway network and planning of pavement maintenance within the short period. By measuring surface deflections with HWD Dynatest, and by having at hand reliable data on pavement structure, thus the basis was formed for creating the mechanical pavement model. After the analysis of pavement surface deflections, idealized models of future condition were established, so-called “pavement condition matrix”. That matrix includes three classes of foundation condition and six classes of pavement condition. Each homogenous section of the analyzed motorway network may be represented by one of models in “pavement condition matrix”. Those models define efective modules of particular layers (for calculation overlay), residual bearing capacity of relevant pavement layers, and other information, significant for calculation. A basis was made that way for calculation of overlay structure. A significant percentage of asphalt layers and cement-treated aggregates layers possess residual bearing capacity. That is the reason to design maintenance strategies through a concept of preventive maintenance for pavement structure within  design period of 20 years in service.