Strength and permanent deformation properties of demolition wastes, glass, and plastics stabilized with foamed bitumen for pavement bases

Abstract

Foamed bitumen (FB) stabilization is an in-place soil improvement technique that has become popular in recent times. Nevertheless, a lack of understanding exists about the strength and deformation responses of FB stabilized recycled demolition wastes in pavements. This paper aims to introduce the application of FB stabilized recycled demolition waste blends with glass and plastic in the pavement base layer. A suite of laboratory tests was undertaken to evaluate the indirect tensile strength, unconfined compressive strength, California bearing ratio, and permanent deformation behavior of FB stabilized blends. Recycled concrete aggregate (RCA) was blended with recycled glass (RG), recycled plastic (RP), and reclaimed asphalt pavement (RAP) in various percentages and the performance of the FB stabilized blends were characterized through extensive experimental testing. A multi-stage repeated load triaxial (RLT) testing procedure was adopted to evaluate the permanent deformation behavior of the unbound and FB stabilized blends under various stress levels. The ITS, UCS, and CBR values exhibited decreasing trends with increasing the RAP, RG, and RP contents. The permanent deformation of the blends was found to be reduced as a result of FB stabilization, most notably for the blends with higher percentages of RAP, RG, and RP. The permanent deformation responses of the blends were ranked using the shakedown concept that indicated the FB stabilized demolition wastes exhibited relatively stable responses under cyclic loads. The deformation response of the blends with 50%RAP and 7%RP changed from incremental collapse to plastic creep as a result of FB stabilization. The results indicated that the FB stabilization of recycled aggregates is a suitable practice for developing more sustainable roads with enhanced ductility and resistance to rutting.