The role of geotechnical zoning in the pavement reinforcement of old roads

Abstract

ln Portugal there are a significant number of old roads that are being subjected to benefaction works, to improve circulation comfort and security. Most of them have a deficient design according to the present traffic needs and the specifications of the Portuguese Road Administration (JAE), showing significant deterioration of the pavement, sometimes increased by the lack of appropriate maintenance. In this paper it is stressed the importance of the geotechnical zoning based on the study of the geology, hidrogeology, drainage and in the beahviour of the natural materials used in the construction and it's relationship with the deterioration observed in the old pavement. Examples are presented using the CBR and soil properties test results, traditionally used in Portugal in the design, and with a more comprehensive approach using all available information, including the old pavement structure and deterioration, to establish the geotechnical zoning along the road. It was possible to conclude that a detailed complete analysis of the field observations and of the laboratory data is an efficient way to create a geotechnical zoning, extremely important to design more realistic pavement reinforcement.