Description
Design of Pavement Reinforcements for Crack Reflection
Jorge Pais
Universidade do Minho, Departamento de Engenharia Civil, 4800-058 Guimarães, Portugal
Jorge Sousa
Consultores e Projetistas de Pavimentos, Rua Zona. Industrial 6A, Casais da Serra, 2665-305 Milharado, Portugal
jorge.b.sousa@gmail.com
ABSTRACT.
The national road network is stabilized and the construction of new roads, and consequently new pavements, will be increasingly reduced. In this way, pavements are no longer designed as new pavements considering the typical failure mechanisms (cracking due to fatigue due to repeated bending of the bituminous layers and permanent deformations due to the compression to which the pavement bed is subjected), but are instead designed as pavement reinforcements, considering the propagation of the cracking existing in the old pavement layers to the new pavement layers, that is, by the reflection of the cracks. This situation is already considered in the most recent version of the AASHTO method (Mechanistic-Empirical Pavement Design Guide). The consideration of crack reflection in a design method is covered by specific procedures not foreseen in the Burmister theory used to calculate forces in new pavements, usually using finite element models with the modeling of cracks in the bituminous layers. Furthermore, the development of a pavement design method requires the calibration of the results expressed in terms of pavement life based on laboratory results, on in situ behavior results, using appropriate calibration factors. In 2005, the authors developed a design method that considers crack reflection, a method calibrated for traditional mixtures and rubber-modified bitumen mixtures produced using the wet method. Having recently emerged bituminous mixtures with reacted and activated rubber (RAR), there was a need to update the method, and this work presents the most recent version of the method, which includes mixtures with bituminous mixtures with reacted and activated rubber, commonly known as RAR.
KEYWORDS: Pavement Design, Crack Reflection, Reacted and Activated Rubber, Design Method.
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