Characterization and Design Criteria for Recycled Warm Mix in Plant -Case Study

Abstract

Half warm mix asphalt recycling (HWMR) is a promising new technique for reclaimed asphalt pavement (RAP) recycling under development in Portugal. The technique is based in mix recycling RAP at low temperatures, between 70ºC and 100ºC. An attempt to apply this technique was made for the first time at EN 244 road, in the stretch between Ponte de Sôr and close to Gavião. The project was initially conceived by “Direcção de Estradas de Portalegre”. The solution was found to be most appropriated for the rehabilitation of the existing asphalt pavement, both from the economical and environmental points of view. Although initially the mixing temperature was supposed to be between 70ºC and 100ºC, higher mixing temperatures were adopted later, during plant production, therefore Warm Mix Recycling (WMR) was used instead of HWMR..

This paper presents the preliminary results of a research project concerning design and performance of WMR / HWMR, using the mix asphalt recycling technique applied at EN244 road as a case study. The aim of this preliminary research work is to recommend design parameters for half warm mix asphalt recycling,. Tests were preformed using laboratory compacted specimens and specimens extracted directly from thepavement in order to establish a mix design criteria (Marshall Stability, Immersion-compression test and Stiffness) and mix performance (Resistance to fatigue with four-point bending test on prismatic shaped specimens and Permanent deformation with Wheel Tracking).