OPTIMIZATION OF NIGER DELTA SOILS AS ROAD CONSTRUCTION MATERIALS: CASE STUDY TRIAL ROAD CONSTRUCTION IN SAMPOU TOWN, NIGERIA

摘要

This study attempted to find a lasting solution to road failures in the Niger Delta regionof Nigeria using different locally available stabilizing binder and additives to improve thequality of the soils in Sampou town. The region is prone to flooding and the soils areknown to be poor engineering materials especially for road construction. Dredged sandis usually used as a replacement for the excavated poor soil or as a surcharge on it.The laboratory investigations showed that the natural soil was a fat-clay with more than85% passing sieve 63 μm, it was classified as A-7-6 and CH and had very lowunsoaked and soaked CBR of 0.56% and 0.38% respectively. This natural soil wasstabilized with different composites of binder and additive: 5% drill cutting ash and 4.5%cement; 20% sand and 5% cement; 5% lateralite and 3% cement. Substantial increasein the CBR of more than 20% after soaking for 96 hours and 5 cycles of soaking anddrying for all the stabilized soils. Constructed trial sections suggested that thesecompositions can be adopted for use in the region for the improvement of the subgradesoils especially after heavy rains and in waterlogged areas.