Recycling of porous asphalt mixtures with PMB to increase sustainable use of non-renewable materials

Abstract

In the Netherlands, porous asphalt (PA) is extensively used as a surfacing layer on motorways to reduce the noise level. Due to the high voids content, the binder in porous asphalt mixture ages strongly and normally PA has a service life around 7 to 12 years. To design a PA mixture by using part reclaimed-PA mixture containing polymer modified bitumen (PMB) is a big challenge for this type of mixture. The involvement of PMB makes it even more complicated. In this study, an ”old” SBS polymer modified bitumen (PMB) obtained from reclaimed porous asphalt (RA) was blended with two virgin binders, one normal penetration grade bitumen and one soft PMB at two ratios. The blending effect was investigated in terms of the rheological properties in order to investigate the potential and the possibilities for recycling porous asphalt with PMB into a new PA mixture with similar or even the same quality as the virgin PA. The results indicate that both the logPen. Model and the S.P. model can be used to predict the full blending effect for PMB RA plus virgin Pen. grade binders and PMB RA plus virgin PMB binders. It should be noted that the logPen. Model is at logarithmic scale and the S.P. model at linear scale. Although recycling PA mixture may benefit more from the addition of virgin PMB because it improves high-temperature permanent deformation resistance, low-temperature cracking and drainage resistance during transportation, it will also consume more energy due to the higher mixing and compaction temperatures for blended binders.