Lateritic Gravels in Sierra Leone Use in Road Construction

摘要

The use of lateritic gravels in road construction in Sierra Leone has been limited by specifications,rnprimarily as a result of their relatively high plasticity and fines content. This has resulted in the use ofrnmore expensive alternatives such as crushed rock, and aggregate- or cement-stabilized lateritic soils. Yet,rnno investigations have been conducted to date to evaluate the actual effect of these properties on thernperformance of pavements. It is proposed that such a study would lead to the modification of the currentrnspecifications to allow for more cost-effective road construction. As part of this study, specificationsrnfrom road projects over the past three decades were examined to reveal that in most cases they followedrnstandard specifications not necessarily appropriate for Sierra Leone.rnThe engineering properties of lateritic gravels from various areas of Sierra Leone were also analyzed, andrnit was noted that they generally exhibit adequate strengths for pavement construction. However, sincernthey tend to be unstable under repeated loads, it is proposed that their durability be evaluated byrnincorporating test sections along roads during construction. The analyses of the soil properties alsornrevealed the regional variations that seem to exist. These variations may result primarily from differencesrnin the parent rock, topography and degree of weathering, and it is proposed that a more thoroughrnunderstanding of these variations would contribute to the development of maps indicating the quality ofrnlateritic gravels throughout Sierra Leone.