This paper describes studies performed by TRL into the use of marginal
quality materials for road pavement construction in the tropics. In the studies a strategy involving four main stages was followed. These included; mapping the location and distribution of materials, determining their properties in the field and in the laboratory, assessing their performance in road construction and under traffic and preparing guidelines for-their use.
The studies were initiated to examine the use of locally abundant natural
gravels and weathered rocks as alternatives to conventional materials in
areas where the latter are unavailable or too expensive. Examples of studies of volcanic-derived gravels in Ethiopia and calcareous gravels in Botswana are used to illustrate the implementation of the strategy in practice.
PTRC. Proc of Seminar H, PTRC Transport and Planning Summer Annual meeting, University of Bath, 7-11 September 1987. TRL - Crowthorne, UK. pp. 29