Investigatingin situstress-dependent behaviour of foamed asphalt-treated pavement materials

Abstract The present research study aims to investigate whether increases in the applied load have an impact on the modulus and the in situ behaviour of foamed asphalt (FA)-treated materials used as base layer in pavements that have been cold in-depth recycled. For this purpose, falling weight deflectometer (FWD) measurements were conducted, using varying load levels and subsequently back-calculation procedures were performed to estimate the layer moduli for each load level in order to investigate the possible stress-dependent and non-linear behaviour of the FA-treated layer material. The pavement response at each load level and therefore the critical strains in the body of the FA layer were calculated. A fibre optic sensors system was used for in situ strain measurements. The relation between the calculated, as well as, the measured strains and the applied FWD loads was used as another criterion of the possible non-linear behaviour of the FA layer. Analysis results did not indicate an in situ stress-dependent behaviour of the FA material. Keywords: cold recyclingfoamed asphaltstress-dependentFWDfibre optic sensors Acknowledgements The authors thank to the Greek Ministry of Infrastructure, Transport and Networks for their support. Also they would like to thank Professor Guy Doré (University of Laval) and his colleagues for their valuable contribution in the framework of the development of the FOS Systems.