Keywords: bituminous sub-ballast, warm mix asphalt, hot mix asphalt, granular sub-ballast, mechanical performance, railway infrastructure.

Bituminous sub-ballast is becoming a common solution in railway tracks since this layer allows for the increase in bearing capacity and at the same time higher substructure protection (lower permeability and greater capacity to dissipate stress) is obtained compared with the conventional solution of granular sub-ballast. However, the application of bituminous sub-ballast could involve a notable increase in construction costs as well as environmental problems associated with the use of Hot Mix Asphalt (HMA) that are commonly manufactured at temperatures around 160 degrees C. Thus, this paper presents an initial study about the potentiality of using Warm Mix Asphalt (WMA), produced at a temperature 25 degrees C lower, as bituminous sub-ballast in railway infrastructure, which would lead to a decrease in fuel consumption and in gases emitted into the atmosphere. With this purpose, this paper focuses on the evaluation of the mechanical performance of WMA (in comparison with conventional bituminous sub-ballast and traditional granular sub-ballast) under diverse load conditions that can occur during the service life of bituminous sub-ballast in railway tracks. Results showed that WMA generally presents a comparable mechanical behaviour to conventional HMA sub-ballast at the time that better performance than traditional granular sub-ballast, which makes it as a potential material due to its economic and environmental benefits.

purchase the full-text of this paper (price £22)

go to the previous paper
go to the next paper
return to the table of contents
return to the book description
purchase this book (price £85 +P&P)