The performance of stabilized pebble bases under light urban traffic in Luanda, Republic of Angola

Abstract

A housing project with 24 km of residential streets, on a site 8 km south of the city of Luanda in Angola, known as the Nova Vida Project was constructed in 2001. A stabilized natural pebble river gravel mixed with red sand was used as the base and subbase layers. Since the performance of this pavement structure was unknown, a study was executed to determine the performance after five years. This paper presents the evaluation of the performance of selected roads in this development. The paper first presents a brief geotechnical and geological overview of the Luso and Muceque/Quelo Red Sands and their road construction properties. Thereafter the as-constructed laboratory test results are presented, and finally the structural performance of the stabilized pebble material is predicted based on the behaviour during the first five years. The dynamic cone penetrometer (DCP) results demonstrated that the structural life of the pavements will exceed the structural design period (design pavement life) of 15 years before reaching a rut depth of 20 mm, if the assumed conditions prevail during the implementation of the proposed maintenance programme. This conclusion was confirmed by the South African mechanistic design analysis.