Description
The deterioration of the South African road network is considered to be primarily the result of a lack of timely maintenance intervention on the ageing existing infrastructure. Bitumen-rubber chip seals have been hugely successful in restoring the integrity of these badly deteriorated roads. In life-cycle assessments conducted over the past 25 years, bitumen-rubber has proven itself as the most cost-effective modified binder in the South African bituminous product spectrum. The objective of this paper is to present case studies and performance of unusual projects where bitumen-rubber was used successfully in single and double seals, in order to demonstrate the solution of the problem, as well as the suitability of the technology by means of an evaluation with the Treatment Performance Capacity (TPC) approach. The paper will give a brief overview of the design approach of bitumen-rubber chip seals. Thereafter several case studies will be presented to provide the background for the evaluation with the TPC approach. The case studies will demonstrate that although bitumen-rubber single seals provide a useful action on badly deteriorated roads, bitumen-rubber double seals are more costeffective and have a longer life than single seals. This view is supported by the TPC analyses.
