This article reviews the use of bitumen mixtures in pavement surfacing applications across the world. The first case study concerns the resurfacing of the Avonmouth Bridge in south-west England, which required a surfacing that would provide long life, water penetration resistance and skid resistance. A Swiss-designed gussasphalt product was used, containing sands, limestone filler, Trinidad Lake Asphalt granules and the polymer-modified binder Nypol 45MA. The material is delivered on site in mobile heating units and spread and gritted by the finisher, followed by rolling. Another new additive, Rediset WMX, from manufacturer AkzoNobel, has been used in the state of Texas, USA, and tested in Europe in the product Norway WAM-Foam, which reduces carbon dioxide emissions, enhances low temperature flexibility and features savings of fuel in manufacture. Trinidad Lake Asphalt is now produced in pellet form for wider end-use applications, including warm mix technology. Another warm mix additive is Sasobit, a high-melt polymethylene from manufacturer Sasol Wax. Originally used to produce rut-resistant mixtures, it features increased stiffness, and has been used successfully with reclaimed asphalt pavement. Manufacturer DuPont produces Elvaloy reactive elastomeric terpolymer resin and Entira Bond with styrene/butadiene, with increased resistance to cracking and fatigue.
Abstract