Effect of temperature and traffic on mix-design of bituminous asphalt for railway sub-ballast layer

Abstract

A wide integrated research has been carried out to assess the suitability of bituminous mixtures as the sub-ballast layer in railways. The influence of temperature on the mechanical characteristics and thermal susceptibility of the bituminous conglomerate—which forms sub-ballast layer of railway lines—has provided the motivation for carrying out a measurement of the thermal cycles in this layer. The evaluation of the average seasonal temperatures has proven to be well interpolated by sinusoidal functions, of which characteristic parameters are determined. To expand the validity of the study in different weather situations apart from Sicily, where the experiment was held, we proceeded to apply the Barber’s temperature model, used to validate pavement structures, which proved to be effective for the railway superstructure. A reference bituminous mixture according the Italian standard was used applying the Superpave mix design. This article illustrates the results obtained after different simulations, following the evaluation of the average seasonal temperatures.