Influence of high temperature on properties of materials used in bridge asphalt pavement structures

Abstract

Bridge deck surface might exceptionally become exposed to extreme high temperature conditions during fires caused, for example by vehicle failures. Bituminous binders and asphalt mixtures are thermoplastic components of surfacing and waterproofing layers, which means that their properties vary depending on the temperature. These materials, when exposed to high temperature conditions, may lose their viscoelastic properties, resulting in failure of pavement. This paper presents the results of experimental research and analyses of the effect of exposure to high temperature for a short period of time on the behaviour of bitumens and asphalt mixtures used for installation of waterproofing layers and bridge deck surfacing courses. The following materials were subjected to thermal conditioning under this research: bituminous waterproofing membranes, traditional mastic (M), mastic asphalt enriched with chippings (SMA-MA), stone mastic asphalt (SMA), mastic asphalt (MA) and asphalt concrete (AC). The temperature of 250°C was found to be the limit above which the bituminous binders permanently lose their viscoelastic properties, this resulting in irrecoverable damage of pavement. It is possible to obtain bridge deck surfaces featuring increased resistance to high temperature exposure during fire by appropriately designing the pavement structure, selecting adequate materials and choosing optimum installation method.