Laboratory evaluation of the physical properties of hot mix asphalt exposed to combustion

Abstract

The behavior of asphalt layers in the event of extreme fire conditions, especially critical in tunnels or underground garages, requires special attention and analysis. The asphalt pavement is flammable in the temperature range of 428 – 530 °C; fires can even occur after only 8 min, and, in addition to toxic smoke, harmful gases may appear as well. During a fire, the asphalt pavement becomes mechanically unstable. The properties and duration of the asphalt layers in fire depends not only on their mechanical properties, but also on the thermophysical properties of the aggregates. The aim of this paper is to examine the physical properties of asphalt mixtures for wearing pavement layers exposed to different combustion temperatures. Two groups of asphalt samples were made; one with stone aggregate (SA) and the other with waste glass as aggregate (WG). The air void content, the voids filled with bitumen, asphalt samples density and bitumen content were tested and analyzed after exposing the samples to temperatures of 470 °C, 495 °C and 520 °C. The results obtained showed improved resistance to high temperatures of asphalt mixtures with waste glass as an aggregate (WG) compared to mixtures with stone aggregate (SA).