Author(s)

F. Lancieri, A. Marradi & S. Mannucci

Abstract

This paper describes the results of the experimental measurements carried out during 2001 and 2005 on two secondary roads built in 1998 using C&D aggregates for subgrade and subbase layers. Field data included structural data in the form of nondestructive testing (NDT) performed with a Falling Weight Deflectometer and laser profilometer, visual condition survey, traffic measurements and construction and maintenance history data. The FWD deflection measurements were analysed to determine modulus values for the various pavement layers while profile data were used to calculate evenness index (IRI). Deflection tests performed in 2001 showed that in-situ pavement performance was better than expected. This performance improvement was explained by self-cementing properties. Field tests repeated in 2005 revealed a meaningful difference in the structural behavior of the road pavements examined: the first, subjected to heavy vehicles, showed a marked improvement in backcalculated moduli of the subbase pavement layer while the second, not subjected to heavy vehicles, maintained practically the same values of layer moduli. These field tests were integrated with laboratory tests performed in order to investigate the time evolution of mechanical characteristics of C&D materials and to evaluate the influence of compaction techniques on the improvement in resistance recorded with the gyratory compactor. The data and results presented confirm that road construction could offer a reliable use for C&D waste recycling. Keywords: C&D , unbound layers, FWD, back analysis, gyratory compactor.

Keywords

C&D , unbound layers, FWD, back analysis, gyratory compactor.