The use of lateritic gravels in road construction in Sierra Leone has been limited by specifications, primarily as a result of their relatively high plasticity and fines content. This has resulted in the use of more expensive alternatives such as crushed rock, and aggregate- or cement-stabilized lateritic soils. Yet, no investigations have been conducted to date to evaluate the actual effect of these properties on the performance of pavements. It is proposed that such a study would lead to the modification of the current specifications to allow for more cost-effective road construction. As part of this study, specifications from road projects over the past three decades were examined to reveal that in most cases they followed standard specifications not necessarily appropriate for Sierra Leone. The engineering properties of lateritic gravels from various areas of Sierra Leone were also analyzed, and it was noted that they generally exhibit adequate strengths for pavement construction. However, since they tend to be unstable under repeated loads, it is proposed that their durability be evaluated by incorporating test sections along roads during construction. The analyses of the soil properties also revealed the regional variations that seem to exist. These variations may result primarily from differences in the parent rock, topography and degree of weathering, and it is proposed that a more thorough understanding of these variations would contribute to the development of maps indicating the quality of lateritic gravels throughout Sierra Leone. (A)
Samenvatting