Comparing Brazilian Flexible Pavements Design Method to AASHTO Design Procedure

Abstract

This work aims to assess flexible pavements designed with the conventional Brazilian method of DNIT comparting to the newest SisPavBR software developed at UFRJ and also the AASHTOWare Pavement, which implements the design method proposed by AASHTO ME, NCHRP 1-37A. To accomplish such task, BR116/RS traffic volume and characteristics were used; nonetheless, it was necessary to create traffic volume bands (N), provided that the DNIT method does not account for vehicles arrangement of axle weight in the same fashion as SisPavBR and AASHTOWare. It was also assessed the construction cost of the kilometer of pavement designed by each method. As a result, while pavements designed by the DNIT required a surfacing thickness of 12.5 cm, SisPavBR required 19.5 cm for the same surface and AASHTO, 40 cm. Similarly, construction cost was higher for the design using AASHTOWare and SisPavBR, when compared to the official method. In addition, an analysis of the pavement life cycle for the pavement designed by the DNIT method behaved well below expected in both analyzes, reaching a case scenario of a 2 months life span. Unmistakably, the need to discuss the evolution of the official method to a more modern approach and aligned to the current Pavement mechanics concept.