Enhancing Geotechnical Properties of Lateritic Clay with Sawdust Ash-Lime Stabilizer

Abstract

One important means of refining the geotechnical characteristics of soils is stabilization. This research sought to improve the geotechnical properties of lateritic clayey soil using sawdust ash-lime (SDAL) stabilizer. Soil-SDAL mixtures were made, after collecting lateritic clay samples and preparing mixtures of lime and sawdust ash in a ratio of 1:2. SDAL mixtures were added to the lateritic clay in increasing percentages from 0 to 10%. The materials’ index properties were determined, and compaction of the Soil-SDAL mixtures was done using four compactive efforts namely Reduced British Standard Light (RBSL), Standard Proctor (SP), West African Standard (WAS), and Modified Proctor (MP). Unconfined compressive strength (UCS) tests were performed on the Soil-SDAL mixtures as well. Results of the tests showed that the soil could be classified as an A-7-5(7) soil with a 13.7% plasticity index. The plasticity index increased with the addition of SDAL mixtures up to 6% after which there was a gradual decline. Meanwhile, maximum dry density (MDD) decreased while optimum moisture content (OMC) increased with SDAL addition. Unconfined compressive strength (UCS) of the soil increased from 38.58kN/m2 at 0% SDAL to a maximum of 129.63kN/m2 at 6% SDAL, after which there was a gradual decrease. Similar trends were noticed at all compactive efforts, indicating consistency in the performance of the stabilizer. Optimum results were achieved at 6% SDAL content, with Modified Proctor compactive effort giving the maximum value of 1,860kg/m3 MDD. The results prove that sawdust ash-lime mixture offers tremendous abilities in improving lateritic clay soil properties.