EVALUATION OF INSITU GEOTECHNICAL PROPERTIES OF ROAD PAVEMENT LAYERS MATERIAL: A CASE STUDY OF MINNA–BIDA ROAD.

Abstract

The intrinsic suitability of some lateritic soils as materials for construction of layers for flexible pavements is evaluated herein. The pavement layers assessed were the base course, sub-base and sub-grade. Laboratory results of samples from these layers show that the CBR values of the sub-grade materials met the requirement while about 40% and 70% of the locations for sub-base and base materials respectively, presented CBR values less than those specified by the local code of Nigeria. Also, the fine proportions as required were significantly absent. This resulted into failure of the road along its profile at many sections, such as the roadway and shoulders. It was noted that the fine proportions would have been leached away due to inadequate drainage facilities at the failed road sections or rather poor quality control during construction. A total reconstruction with adequate drainage facilities is suggested for this road due to its importance in Nigeria, and with the adequate materials.