Experimental study on potential of oyster shell ash in structural strength improvement of lateritic soil for road construction

This study investigated the effect of oyster shell ash (OSA) on the geotechnical properties of lateritic soil. Laboratory studies were performed using lateritic soil treated with up to 15 % OSA. The result shows a decrease in maximum dry density (MDD) with corresponding increase in optimum moisture content (OMC). Unconfined compressive strength (UCS) values generally increased with increased OSA content and curing age, while resistance to loss in strength increased to peak of 18 % at the threshold of 6 % OSA content. Peak California bearing ratio (CBR) values (soaked and unsoaked) were obtained at a threshold of 6 % PSA content. The Fourier transformation infrared (FTIR) spectroscopy of the soil, OSA and soil + OSA blend show the distinctiveness of the relevant functional groups in relation to their specific band. The treated soil show H-O-H bending of water linked to 2Al3+, Si-O, Si-O-Si. The scan electron microscopy (SEM) and electron diffraction spectroscopy of treated soil revealed the formation of compounds responsible in strength improvement of the soil. Generally, OSA show significant strength improvement on the lateritic soil. This study has shown that OSA can be beneficially used in lateritic soil improvement and is also recommended as admixture in either lime or cement stabilization of deficient lateritic soil for use in road construction. © 2020, Chinese Society of Pavement Engineering. Production and hosting by Springer Nature.