The Hoopstad long-term road pavement performance (LTPP) experiment was constructed in 1962 as part of the road P 21/3 on Route R700 between Hoopstad and Bultfontein in the Free State Province of South Africa. The purpose of the experiment was to evaluate the performance as base course of a fine-grained, non-plastic, A-2-4(0), aeolian, Kalahari-type sand stabilized with various amounts of ordinary and portland blast furnace cement, lignosulfonate, tar and bitumen in comparison with “crusher-run” graded crushed stone and neat, unstabilized sand as control sections. In this report the performance of the stabilized sections is reported in comparison with the neat sand and crusher run sections.
Whilst there is a dearth of performance- and traffic- related information over the years, the fact remains that in June 2017, after 55 years and some 1.5M E80/lane, all the sections were still there and carrying traffic, none had been rehabilitated, and none appears to have ever exhibited structural failures. Neat or weakly cemented designs using Kalahari sand in all layers offer tremendous potential for the construction of relatively inexpensive, all-weather, sealed low volume roads in the vast area of arid and semiarid southern Africa in which similar sands and a scarcity of gravel and rock occur.
This project is funded by DFID under the Applied Research on Rural Roads and Transport Services through Community Access Programmes in Africa and Asia (AFCAP2 and AsCAP)
Netterberg, F. (2017). The Hoopstad Stabilized Kalahari Sand LTPP Experiment After 55 Years – Volume 1: Final Report. London: ReCAP for DFID.
Published 18 December 2017