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Increasing road construction activities in Nigeria has led to increased demand for lateritic soil (LS), whose properties vary from one location to another, and. The properties of some of this laterite deposits along road alignment can be improved to enable it withstand traffic loads. This paper presents results of the laboratory evaluation of LS stabilised with oil palm fibre ash and cement blends, with a view to determine its suitability as flexible pavement construction material. The mixtures were subjected to British Standard heavy (modified Proctor) compaction energy to determine their strength characteristics. Test results show that the properties of LS improved with oil palm fibre ash and cement treatment. The maximum dry density decreased with corresponding increase in optimum moisture content as the cement content increased from 0% to 6% and the LS content of the mixtures decreased with increased oil palm fibre ash, at a fixed per cent of cement. The peaked California bearing ratio of 190.09% (soaked) recorded for the 80% LS + 14% OPFA + 6% C mix proportion, with 14th day unconfined compressive strength of 785.75 kN/m2, cohesion of 140 kN/m2 and angle of internal friction of 25°, can be used as a base material in road construction. Further work may be encouraged to assess resilient modulus of this material under cyclic load. [ABSTRACT FROM AUTHOR]

Massive sugarcane bagasse ash waste is generated from the combustion of fibrous residue of sugarcane. Also, highway reconstruction work generates large volume of reclaimed asphalt pavements that are disposed as waste. This paper present results of stabilization and laboratory evaluation of the characteristics of these wastes with a view to determine its suitability as flexible pavement material. The mixtures were subjected to reduced British standard light (reduced Proctor), British standard light (standard Proctor), West African standard and British standard heavy compactive efforts to determine the compaction characteristics, California bearing ratio, durability and water absorption characteristics of the mixes. Test results show that the properties of reclaimed asphalt pavements waste improved with sugarcane bagasse ash stabilisation. The maximum dry density decreased as the optimum moisture content increased with higher sugarcane bagasse ash contents in the mixes. Maximum California bearing ratio values of 28% (unsoaked) and 14% (soaked for 24 h) were recorded for 50% RAP + 50% SCBA mix that satisfied durability requirements and can be used as subgrade material in flexible pavement construction. This research is based on CBR determination. Further work may be encouraged to assess resilient modulus of this material under cyclic load. [ABSTRACT FROM AUTHOR]