Effect of the Addition of Zeolites on the Resistance to Permanent Deformations of Mastic Asphalt Bridge Pavement

Abstract

The mastic asphalt mixture (MA) is one of the first mineral and asphalt mixtures used in history. Its composition and structure allow it (the mixture) to be produced both in industrial conditions (in mineral and asphalt mixing plants) and in field conditions—in mobile boilers (especially when the produced mixture is used to repair damaged surface). The high proportion of the sand fraction makes the mixture highly workable, allowing it to be laid/incorporated without special equipment. MA, however, also has some drawbacks. The asphalt content is higher than in other mixtures, which can make it prone to plastic deformation. Mastic asphalt requires higher processing temperatures than other “hot” mixtures. Mastic asphalt mixtures are installed as road pavement layers and, because of their high density, as the protective layer on roof felt isolation on bridge decks. The high temperature of embedding creates a risk of damaging the roof felt, as its typical temperature resistance is lower than 180 °C, whereas the temperature of the mastic asphalt mixture is higher. The use of zeolites can enable reconciliation of technological requirements of mastic asphalt and asphalt roof isolation. The mixes MA 8 and MA 11 containing 0 and 5% of two types of zeolites and asphalt binders 35/50 or elastomer-SBS-modified asphalt binder PMB 25/55-60 were used in the research. Laboratory tests revealed that the addition of a 5% amount of zeolite by asphalt mass makes it possible to reduce the mastic asphalt laying temperature by up to 30 °C, which seems to be very important from ecological, economical, and pavement durability points of view.