PLASTICITY AND COMPACTION CHARACTERISTICS OF LATERITIC SOILS IN TOUNGO AREA, ADAMAWA STATE, NIGERIA

Abstract

The plasticity and compaction characteristics of lateritic soils in Toungo area, Adamawa State, Nigeria were investigated to establish their suitability as civil engineering construction materials. Ten disturbed samples were subjected to geochemical and geotechnical analyses. The dominant oxides ranges are: silica (SiO₂) (42.85 % to 45.34 %); aluminum oxide (Al₂O₃) (39.12 % to 39.20%); and iron-III-oxide (Fe₂O₃) (6.73 % to 8.96 %). The percentage fines, specific gravity SG and natural moisture content NMC ranges are (1.23% - 45.36 %), (2.57 - 2.64) and (11.65 % - 29.12 %) respectively. Samples TNG₈ and TNG₁₀ recorded more fines and higher NMC due to higher void ratio and clay in their void spaces. The liquid limits LL, plastic limits PL and plasticity index PI ranges are (17.25 % - 48.75 %), (13.15 % - 27.85 %) and (4.10 % - 20.90%) respectively. The ranges of maximum dry density MDD and optimum moisture content OMC are (2.830 g/cm³ - 4.15 g/cm³) and (6.15 % - 14.15 %) respectively. The soils are generally poorly graded and sandy clay with plastic fines. All the lateritic soil samples (except TNG₈ and TNG₁₀) are suitable as fill materials; only samples TNG₄, TNG₅ and TNG₉ are suitable as base and sub-base materials; samples TNG₁, TNG₂, TNG₃, TNG₆ and TNG₇ can be regarded as fair; while samples TNG₈ and TNG₁₀ can only be used after stabilization.