Designing a one-and-a-third seal using marginal aggregate by means of the modified tray test

Abstract

Paper presented at the 21st Annual South African Transport Conference 15 - 18 July 2002 "Towards building capacity and accelerating delivery", CSIR International Convention Centre, Pretoria, South Africa.

During February 2000, heavy rains in the Limpopo Province of South Africa, resulted in major floods causing severe damage to the road infrastructure. Road P278/1, from Wyliespoort to Sibasa, had to be closed as a result of wash-aways, damage to fills as well as mudslides in the Thate Vondo Pass. Emergency repairs and opening of the pass by removing the mudslides further damaged the surfacing and the layers of the road. Limited funds were allocated for emergency road repairs, patching and base reconstruction. Owing to the wide-ranging repair works that had to be undertaken at the time, the Northern Province Roads Agency (NPRA) experienced shortages in material resources, such as crushed stone for chip sealing. Special measures had to be taken to ensure that the quality of work was maintained despite the shortages. Hence, the NPRA requested consultants and CSIR-Transportek to investigate alternative designs for chip seals for, for instance, the reconstructed portions of P278/1.