Experimental Study on the Effects of Heat and Heating Duration on Expansive Soils Plasticity Determination From Parts of Southeastern Nigeria

Using the residual soils collected from Abakaliki Metropolis as a case study, the aim of this work was to evaluate the effect of heat and heating duration on Atterberg Limit (Plastic limit and Liquid limit) test results. Additionally, the study sought to determine if the engineering testing settings for soils in laboratories could be statistically optimized to account for any anticipated or unforeseen events and whether the optimized soil testing findings might take the place of laboratory-generated data. The five samples from Abakaliki metropolis were tested using particle size distribution and Atterberg's Limit tests. The samples were found to be mostly fines according to the gradation curves, with substantial quantities of gravel and silt as well as clay-sized particle. The results of the samples' liquid and plastic limits vary from 30 to 68 and 24 to 47, respectively, having plasticity index between 6 to 18. Statistically, the correlation coefficient (R²) indicate that residual soils must be heated under the standard conditions (for 24 hours at 105°C). Therefore, in order to account for any anticipated or unknown events, the engineering tests conditions of soils within the laboratory cannot be statistically optimized, and optimized soil testing findings cannot take the place of laboratory generated results.