Valorization of Agro-Waste for Mechanical Properties’ Improvement of Lateritic Soil for Sustainable Construction

Obianyo, Ifeyinwa Ijeoma (2020-09-06)

Main Thesis


This study presents the results of a combined theoretical, experimental and statistical study of the mechanical performance of stabilized lateritic soil for sustainable construction applications. The lateritic soil was stabilized with different percentage of bone ash (5%, 10%, 15% and 20%),hydrated lime (3%, 9% and 15%) for the project I whereas four different matrices with bone ash content of 0, 3, 6 and 9% of the weight of lateritic soil were used for the lateritic soil stabilization in project II. The bone ash and palm bunch ash were added to the soil sample in equal proportion at a varying proportion of 0%, 2%, 4% and 6% by weight of the soil in project III. Lateritic brick samples obtained were cured at different temperature and ages. The effects of these stabilizers on the morphology and mechanical properties of the composite were investigated using Scanning Electron Microscopy and Universal Testing Machine respectively. The microstructural analysis gave a morphology with reduced porosity for the stabilized soil samples whereas, the results of the compressive strength tests indicated that the compressive strength of the lateritic soil was improved by the addition of the different stabilizers. The study also presents the prediction of compressive strength of stabilized bricks using Multivariate statistical models. Non-linear and mixed models with higher R2 performed better than the linear model in predicting the compressive strength of the stabilized bricks. The mixed model with R2 of 97% was identified as the best-fit model in predicting the compressive strength of the stabilized bricks. The results indicate that agro waste (cow bone and palm bunch) can be valorized through conversion to ash which can be used as an effective stabilizer for lateritic soil. Also, it can be used for making bricks with higher compressive strength compared to conventional stabilizers. The implications of the results for potential applications in the making of lateritic bricks for the construction of sustainable and affordable buildings include lower building costs, bricks with high compressive strength and reduction in the use of cement for building construction.