Incinerator residue for roads

Abstract

A study was conducted by the authors to assess the feasibility of using incinerator residue in road construction. Residues from Singapore incinerators were characterized. Various combinations of mixes comprising local clayey-silty-sandy soil and incinerator residue with or without lime were tested for their suitability for use as road subbase/subgrade. Also, bituminous mixes comprising varying proportions of incinerator residue and granitic aggregates were tested to determine their suitability in road surfacings. This study has revealed that the incinerator residue, although inferior in quality as compared to granitic aggregates for use in dense bituminous mixes for road surfacings, has properties that justify applications in areas where high-quality aggregate is not required. The road subgrade soils can be economically stabilized by using an admixture of incinerator residue from 50 to 75% along with as low as 2.5 to 5% lime. For bituminous mixes, the optimum binder requirement of 10 to 12% makes it quite expensive. However, the use of incinerator residue as unbound base or subbase material with or without blending with natural aggregates is feasible. The incinerator residue also has the potential for use as a free-draining friction course using only 4 to 5% bitumen. Because of its compatibility to bitumen adhesion, stripping is considerably resisted.