GB5® Mix design: A new approach for aggregate grading optimization for heavy duty flexible pavements

Abstract

Since 2008, EIFFAGE has developed an aggregate optimization method (maximum contact and minimum space between aggregate particles) combined with the use of special binders (pure, multigrade or polymer-modified bitumen depending on the traffic concerned), to formulate the high-performance asphalt bituminous mix known as GB5®. During that time, numerous roads designed for heavy traffic have been built using this innovative technique, representing more than 1,000,000 tons at the end of 2014, mainly in France and, more recently, in South Africa. This article presents the result of collaboration between IFSTTAR and EIFFAGE aimed at scientifically relating the specific characteristics of the aggregate skeleton of GB5® to its outstanding mechanical properties, via 2D-image analysis and complete mechanical characterization.