Resumen
With inherent advantages in environmental performance, land use, energy consumption and safety, railways are an essential component of a competitive and resource-efficient transport system. However, railways have still to face several important drawbacks in order to reinforce its competitiveness against the road mode. Reducing maintenance costs has been appointed as one key goal of Infrastructure Managers (IMs), as Western Europe spends annually between ?15 and ?25bn to maintain and renew a railway network of about 225,000 km (FP7 Mainline Project, 2011-2014). Future prospects of mobility growth (passenger-km is to be doubled in 40 years) will increase maintenance needs, evincing the need of innovative solutions that downsize maintenance costs. The increasing demand of higher axle loads and higher speeds has led to the improvement of track components (e.g. harder and heavier rails, pre-stressed sleepers, etc.). However, there has not been a significant change in ballast aggregates, even though it is the main cost-driver of maintenance costs. In this context, NEOBALLAST emerges as a high-performing, long-lasting and eco-friendly ballast aggregate solution designed to overcome two of the most important drawbacks of railway tracks: track degradation and noise and vibrations (N&V). Whilst the former is the main trigger of maintenance and eventually renewal works, thus representing one of the main cost drivers for IMs, the latter has become an issue of paramount importance not only to IMs but the whole EU, since according to the European Environment Agency rail noise affects around 12 million people during day time (55dBA) and 9 million at night (50dBA). NEOBALLAST is a research project funded by MINECO (Spanish Ministry of Economy and Competitiveness) carried out by COMSA, MAPEI, UPC and ADIF. NEOBALLAST benefits have been proven in an extensive laboratory campaign involving both reduced and large-scale testing. This paper will summarize the results obtained in terms of mechanical and vibration mitigation performance of NEOBALLAST aggregates itself and their behaviour as a whole.