Blending as a Strategy for Reusing Municipal Solid Waste Incinerator Ash in Road-Base Construction

Abstract

Bottom and combined ash samples from municipal solid waste incinerator (MSWI) facilities in Florida were compared with industry aggregate standards to determine suitability for use as a road base. Although MSWI ashes tested in this work generally conformed to these standards for bearing strength (i.e., limerock bearing ratios above 100%), blending with commercially available aggregates is proposed as a strategy for improving overall material homogeneity and quantity. This work presents that MSWI ash can exhibit acceptable parameters defined in existing specifications for road-base materials on their own or by blending with commercially available aggregates, bolstering existing supplies of base materials while contributing to landfill diversion. The overall trend for bearing strength decreases with increasing MSWI bottom ash replacement (except for recycled asphalt pavement), but there appears to be a positive correlation between blend coefficients of uniformity (Cu) and bearing strength (R2=0.5290). This suggests that gradation and material types may be parameters for identifying potential blends for advanced testing and developing quality control and assurance standards for material production and construction.