The Advantages of Concrete Pavements in Tunnels

A 21 km long motorway is planned to be constructed through the western suburban of Stockholm. The motorway will mainly be localized in tunnels with a total length of 18 km. The intention is that the tunnel pavement shall be constructed as a jointed plain concrete pavement (JPCP) resting on an asphalt-treated base. Compared with the asphalt pavement, the concrete pavement has both advantages and disadvantages. Important advantages are load-carrying capacity, resistance to concentrated long-term loads and high temperatures, wear resistance, durability, and brightness. High durability means low maintenance costs. Weaknesses are brittleness in tension, shrinkage, high construction costs, and complicated repair if necessary. Some of the advantages and disadvantages change when the concrete pavement runs through a tunnel. The load-carrying capacity increases, the subgrade is more even, the thermal stresses are reduced, and the shrinkage is reduced whereas the importance of brightness and fire safety increases. The bright surface needs less energy for illumination and the consequences of a fire are much more severe in the tunnel than outdoors. The full paper discusses these factors and several minor ones more in detail. Recent studies show that the fuel consumption is less when a vehicle runs on a concrete pavement than on an asphalt pavement. Despite the fact that the difference is limited to 1 percent for personal cars and 2 percent for lorries, the savings in consumed fuel will be substantial during the service life due to very high anticipated number of vehicles.