The Jwaneng LTPP Experiment: Performance Over 14 Years and a Comparison Between Kalahari Sand- Asphalt and Calcrete Base Courses

Abstract

The Jwaneng long-term pavement performance base course experiment on the Kanye-Jwaneng road in Botswana consisted of 12 test sections of wet-mix and foamed Kalahari sand-asphalt and 11 test sections of mostly substandard calcrete base course with two control sections of gravel base, all under a double surface treatment. The purpose of the experiment was to evaluate various alternative base material quality designs for roads in the Kalahari where good quality gravels are scarce. Although the performance of most of the sand-asphalts and some of the calcretes was marred by construction defects, monitoring for 13 years and 0,4 ME80 showed that both types of base course were viable options for at least 1,0 ME80 and that untreated calcretes previously regarded as too inferior could be used as base course. The performance of the cement, lime and mechanically stabilized calcretes was inferior to that of their untreated equivalents.