Cracking response and service life prediction of flexible and semi-rigid road pavements implementing M-E PDG 2002 code

This study investigates the effectiveness of different construction approaches in relation to the major distress modes affecting flexible and semi-rigid pavement overlay system. Cracking predicting and its control are key components in design of new and exiting pavements. From this point of view the possibility of evaluating the damage by an incremental calculation over the entire target of design life is very interesting. The M-E PDG 2002 (Mechanistic-Empirical Pavement Design Guide v.1.003) software allows to assess the effectiveness of a trial design relating to performance criteria defined by the designer, predicting the service life of the considered pavement system. In particular, it shows the evolvement of structural distresses, as bottom-up fatigue (or alligator) cracking, surface-down fatigue (longitudinal) cracking, permanent deformations (rutting) and thermal cracking, through the design life, evaluating the influence of materials characteristics, thickness of layers, climate and traffic on pavement service life. In this paper the Authors show the results obtained using the above-mentioned software, adopting different pavements typologies (conventional, full-depth, semi-rigid, inverted-section), in order to determinate design solutions which are suitable for inhibiting or limiting the cracking phenomenon and the rutting, evaluating the influence of design parameters. In such way, the study offers useful suggestions that can be used by asphalt pavement designers to reduce in particular the possibility of premature cracking, so as to increase the service life of pavement system.