Life Cycle Cost Assessment of Bitumen Stabilised Ballast: a novel maintenance strategy for railway track-bed

In railway sector, the high quality of the track is ensured by adequate construction methods and frequent maintenance. To reduce the maintenance frequency diverse techniques have been recently developed. Among others, bitumen stabilised ballast (BSB) represents an innovative solution designed to increase ballast service life and reduce overall maintenance burdens. This technology, which can be used for new track-beds as well as to reinforce existing ones, consists of the use of bitumen emulsion (BE) poured or sprayed at ambient temperature onto the ballast. The objective of the present work is to assess the economic feasibility, encompassing the estimation of the costs of the environmental impacts, of this innovative technology (BSB), compared to the traditional ballast (TB). This purpose is achieved using a lifecycle approach where economic and environmental impacts are combined to return an integrated model. Results of Life Cycle Cost Assessment carried out for the baseline scenarios (with respect to traffic level and quality level set for the infrastructure) indicated that: the BSB technology, used since the construction stage and during the routine tamping, can provide economical savings. Sensitivity analysis to main parameters affecting results showed that these savings can vary significantly, especially in relation to the traffic and the discount rate.