GEOTECHNICAL PROPERTIES OF LIME AND BAMBOO STEM ASH STABILIZED SOILS FOR ROAD CONSTRUCTION IN SOUTH-WESTERN NIGERIA

Abstract

The state of any road layer today and in the future is primarily dictated by the soil beneath its foundation, and knowing enough about the Engineering qualities of soil and the sub-soil condition is crucial in foundation design. This research looked at the geotechnical qualities of soils stabilized with Lime-and-Bamboo Stem Ash (BSA) mixture. Soil samples were obtained from each state in the study area and transported to the laboratory, where they were stabilized with 6% lime and 0 to 10% BSA. California Bearing Ratio (CBR), Compaction, Unconfined Compressive Strength (UCS), and Triaxial tests were performed on the combined samples. The local additive was also subjected to a chemical examination. The results showed that BSA additive has a high SiO2 content. As BSA content increases, all strength properties (Maximum Dry Density (MDD), CBR, UCS, Cohesion (C), Shear strength (S) and Angle of Internal Friction (ϕ)) increase and reached peak at 6% BSA content, thereafter decrease; however, Optimum Moisture Content (OMC) decreases. The peak values are 2475 kg/m3, 58.53%, 45.32%, 638.9 kN/m2, 137 kN/m2, 290.57 kN/m2 and 41° for MDD, soaked CBR, unsoaked CBR, UCS, C, S and Ø respectively. After going through the process, almost all of the unsuitable soil samples became suitable for use as pavement layer materials. As a result, a mixture of 6% lime and 6% BSA content is strongly recommended for soil improvement, particularly for road construction in South-Western Nigeria.