Waste Products as Highway Materials in Flexible Pavement System

The purpose of this study is to investigate the use of industrial by-product mixtures as construction materials. Fly ash, which is a by-product of coal combustion, is mixed with fine-grained material, a by-product from an aggregate processing operation. Neither material exhibits satisfactory engineering properties by itself. However, if combined, the resulting material properties are improved and potential applications may be found within pavements, structural fill for embankment construction, or as backfill behind abutments and retaining walls. For this paper, the materials are investigated for use as highway materials within a flexible pavement system. In order to demonstrate the benefit of the material mixture toward improvement of overall pavement performance, predicted pavement lives for structures having subgrades consisting of aggregate waste, fly ash, and a mixture of aggregate waste and fly ash are compared.