This paper presents a study of the behaviour of eight road binders(one reference bitumen and 7 modified bitumens) used in porousasphalt wearing courses of an experimental road built in 1985.The complex moduli as well as different other characteristicsof the binders were determined on the original binders and mixtures.A relationship between the complex modulus of binders and thatof the corresponding mixtures has been validated for the caseof modified bitumens. The complex moduli as well as differentother characteristics of the binders were determined after differentexposure times in a laboratory simulated long term ageing test.For some of the binders, these results were compared with theresults obtained on tbe binders extracted from cores on the mixes,in service for 12 years. It was investigated whether the complexmoduli of the aged mixes could be estimated on the basis of thatof the aged binder, with the help of the relationship betweenthe complex modulus of the binders and mixtures.