Recycled-Glass Blends in Pavement Base/Subbase Applications: Laboratory and Field Evaluation

This paper presents the findings of a field and laboratory evaluation on the use of recycled glass blends as unbound pavement base/subbase materials. The parent recycled aggregates studied in this research were Fine Recycled Glass (FRG), Recycled Concrete Aggregate (RCA) and Waste Rock (WR). The geotechnical performance of the recycled aggregate blends of particular interest in this research were FRG blended with RCA (FRG/RCA) and FRG blended with WR (FRG/WR) in pavement base applications. The geotechnical performance of a trial road pavement was assessed by means of initial laboratory tests and subsequently field tests. The initial laboratory experimental programme included specialized geotechnical tests including Repeated Load Triaxial and triaxial tests to characterize the recycled materials. The subsequent trial road pavement constructed comprised of 7 different sections of FRG blends in the pavement base varying from 10 to 30% recycled glass content as well as 2 control sections with RCA and WR. Field tests were undertaken with nuclear density gauges and Clegg Impact Hammers to assess the performance of the various trial pavement sections. The recycled glass blend with 20% glass content was found to be the optimum level, where the blended material was workable, and also had sufficiently high strength. The field testing results indicated that FRG blends are suitable in pavement subbase applications and is a viable additive when used in limited proportions with other recycled aggregates in pavement subbases. FRG blends may however not fully meet specified requirements as a pavement base material.