Study on thermal parameters of asphalt concrete for countermeasures against high surface temperature of pavement in tunnel

Abstract

It is reported that the surface temperature of asphalt pavement in a road tunnel in an urban area in summer days gets hot especially when the tunnel is long and the traffic volume is heavy. Since the asphalt pavement absorbs a large amount of heat generated by vehicles and keeps it for a long time, a high-temperature environment in the tunnel also continues for a long time. This phenomenon brings uncomfortableness for users, especially for motor-bikers and maintenance workers. On this background, this study aims to estimate the thermal parameters of the various types of asphalt concrete and investigate their effects on a high-temperature pavement surface. Six types of asphalt concrete specimens were tested in a wind-tunnel where a hot temperature air inside was generated by a forced circulation boiler system. Thermal parameters: specific heat capacity, heat conductivity, heat diffusivity, and heat transfer coefficients were analysed using a one-dimensional partial differential heat transfer equation and a finite difference approximation method. Additionally, the effects of different basement boundary conditions and water spray on the surface temperature were investigated to find effective countermeasures to decrease the surface temperature of asphalt concrete in the tunnel.

Keywords:

• Asphalt concrete
• thermal property
• heat transfer
• road tunnel
• finite difference method

Disclosure statement

No potential conflict of interest was reported by the authors.