Suitability of Municipal Solid Waste Incineration Bottom Ash as Sub-Base Material for Construction of Road T

Abstract

Incineration bottom ash is a form of ash produced in incineration facilities and this material is discharged from the moving grate of municipal solid waste incinerators. Geotechnical investigation is one of the effective means of detecting and solving pre, syn and post constructional problems. The geotechnical properties of incineration bottom ash and their suitability as sub-base and base materials for road construction have been evaluated. All analyses were carried out in accordance with the British Standard Institution. The natural moisture content ranged from 10.20% to 10.27%, specific gravity ranged from 2.36 to 2.39, liquid limits ranged from 40.50% to 41.00%, all samples were non plastic. The maximum dry density ranged from 1.81 mg/m3 to 2.39 mg/m3 while the optimum moisture content varied from 9.21% to 9.29%. The particle size distribution for percentage passing BS sieve size 200 (0.075 mm) ranged from 0.66% to 0.69% and fall under-fine grained silt sand samples according to the USC system. The california bearing ratio was low at 6% for all samples which makes them fail for use as sub-base materials, thereby requiring application of stabilizing agent such as cement, lime, gravel, etc before use for road construction. The evaluation reveals that all the samples of incineration bottom ash contain no plastics, Maximum Dry Densities (MDD) and Optimum Moisture Contents (OMC) are lower. The samples of incineration bottom ash were classified as A-2-7, group index 0, granular based and are suitable for use as sub-base materials for road construction when compared to the standards prescribed by American Association of State Highway and Transport Officials system (AASHTO 1986), Unified Soil Classification System (USCS) and Federal Ministry of Works and Housing (1997) for use of materials as sub-base materials for road construction. The information obtained from the geotechnical properties of incineration bottom ash obtained from Halden Nigeria Limited, Golden Years Nigeria Limited and Boskel Nigeria Limited will serve as baseline information for use as a sub-base material for road construction and as supporting data for waste to road resources material