This study explored the potentials of sodium hydroxide (NaOH) for the improvement of the properties of lateritic soil (LS) intended for use as construction material for rural roads in the North-eastern part of Nigeria. The soil was classified as A-6(13) and CL according to the American Association of State Highway and Transport Officials (AASHTO M 145-2012) and the Unified Soil Classification System (ASTM D 2487-2011). The soil is treated to evaluate the effectiveness of NaOH in treating lateritic soil with 1, 3 and 7 molar concentration of NaOH and compacted using two methods of compaction, the British Standard Light (BSL) and British Standard Heavy (BSH). Unconfined compressive strength (UCS) and Californian bearing ratio (CBR) tests were conducted on the compacted specimens. The results obtained show a general improvement in the engineering properties of the soil with increase in molar concentration of NaOH, particularly, when compacted at the BSH energy level. The maximum 7 days UCS values of 909 kN/m2 and 1106 kN/m2 were obtained at 7 molar concentration for the BSL and BSH energy levels. These values are within the range of 750 – 1500 kN/m2 UCS value specified by the Nigerian General Specification (2013) for sub-base materials. In the case of the CBR, at 3 and 7 molar concentrations for BSH effort, CBR values of 33% and 38% were recorded while 34% CBR value was recorded at 7 molar concentration for BSL effort, these values also met the minimum requirement of 30% CBR specified by the Nigerian General Specification for sub-base construction.Keywords— Lateritic, Sodium hydroxide, Soil, Rural roads.
Performance Evaluation of the Effect of Sodium Hydroxide on Geotechnical Properties of Lateritic Soil for Rural Road Construction