Investigation into the Geotechnical Properties of Selected Lateritic Soils from Minna as Pavement Materials

Abstract

This study presents an evaluation of some geotechnical properties of selected lateritic soil samples around Minna, Niger State for pavement application. Sixteen (16) lateritic soil samples were collected from five borrow pits within the study area. The samples were subjected to physical, mineralogical, index, compaction and strength properties tests. The samples were further characterized according to AASHTO and USC systems. The natural moisture content values of samples ranged between 2.03-34.24%.Specific gravity values were in the range of 2.47-2.70 while bulk density ranged between 1.76-2.09g/cm3.The particle size analysis showed that ten(10) of the lateritic soil samples were gap-graded while six(6) were poorly graded. Eleven (11) of the samples had more than 35% of their constituent passing sieve No.200 (0.075 mm), while five (5) of the samples have less than 35% fines content. The compaction relationship of samples compacted at British Standard Light energy gave values between 1.52-1.96g/cm3 and 9.2 - 20.6% for MDD and OMC respectively. Strength property evaluation of samples revealed an average unsoaked CBR value of 11.78% with a range of 0.1–5 kPa for unconfined compressive strength. Results from XRD showed that all samples except PG3 contain Kaolinite mineral in varying proportion. Quartz mineral were found in the range of 20.83-76.45%.Clay minerals were generally less than 7%. Based on plasticity index and liquid limit requirements, five (5) of the test samples are suitable for base course application, while only one (1) samples met the requirements as sub-grade material. Ten (10) of the samples will require some forms of treatment to improve or remedy their engineering deficiencies in pavement or other applications.