Understanding the effect of compaction energies on the strength indices and durability of oyster shell ash-lateritic soil mixtures for use in road works

Abstract

The current study examined the use of experimental and statistical approach to assess the influence of compaction energies on geotechnical behaviour of lateritic soil stabilized with up to 15 % oyster shell ash (OSA) by weight of the dry samples. The outcomes portray that the maximum dry densities (MDDs) of both untreated and treated soil samples decreased with increased compactive efforts whereas the optimum moisture content (OMCs) reduced. California bearing ratio, CBR (soaked and unsoaked) and unconfined compressive strength, UCS (7 and 28 days) values increased with higher compactive effort and OSA content. The statistical results indicated that OSA content, compactive energy (CE), plasticity index (PI) and percentage fine content (PF) have effect on the strength characteristics of lateritic soil. Generally, the study indicated that OSA content up to 9 % and higher compactive effort is adequate for enhancing the geotechnical behaviour of lateritic soil. However, rather than use OSA as stand-alone additive, it is recommended that cement or lime be used as admixture in OSA-lateritic soil so as to provide an effective hydraulically bound material for construction application.

Keywords

• lateritic soil
• oyster shell ash
• compaction energies
• strength characteristics
• durability
• statistical analysis