Optimization of bituminous sub-ballast in railways infrastructures under sustainability criteria
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Pirozzolo, LucaEditorial
Universidad de Granada
Departamento
Universidad de Granada. Departamento de Ingeniería de la Construcción y Proyectos de IngenieríaMateria
Ferrocarril Materiales bituminosos Subbalasto Resistencia de materiales Asfalto Pavimentos de asfalto Caucho Reciclado Materiales de construcción Mecánica
Materia UDC
621 25
Date
2017Fecha lectura
2017-06-05Referencia bibliográfica
Pirozzolo, L. Optimization of bituminous sub-ballast in railways infrastructures under sustainability criteria. Granada: Universidad de Granada, 2017. [http://hdl.handle.net/10481/47126]
Sponsorship
Tesis Univ. Granada. Programa Oficial de Doctorado en: Ingeniería CivilAbstract
In recent years, the railway sector has focused on more sustainable constructive techniques and more
durable solutions such as the inclusion of bituminous sub-ballast in order to reduce track degradation
whilst improving its quality. The use of bituminous layer in railways tracks is regarded as an appropriate
solution for improving the strength of the section. In comparison with traditional granular sub-ballast,
these materials allow for both an increase in bearing capacity and greater protection of the substructure.
However, the fact that these materials are manufactured at a temperature of 160°C means that their
application can incur significant construction costs, along with a rise in pollution and energy consumption.
In this regard, there is a need for the use of new techniques to produce asphalt, such as the reuse of waste
materials or manufacturing with low-temperature technology, both of which allow for lower energy
expenditure without changing its in-service mechanical performance, as well as reducing the general costs
of this layer. In this context, this thesis therefore aims to, on the one hand, study the possibility of using
sustainable bituminous sub-ballast manufactured from waste materials such as crumb rubber, which is
recycled rubber produced from scrap tires and reclaimed asphalt pavement (RAP) from road pavement at
the end of their service life. A further aim is to study the possibility of using WMA manufactured at lower
temperatures, as bituminous sub-ballast. To this end, this thesis is focused on evaluating the mechanical
behaviour of bituminous materials (under both routine and adverse temperatures) in comparison with that
presented by conventional sub-ballast. In particular, performance is examined with respect to the main
requirements that need to be met by these materials (resistance to plastic and punching deformations,
bearing capacity, stress dissipation, cracking resistance, and waterproof properties) for their use in railway
tracks.
The results demonstrated that all the sustainable solutions studied, offer a suitable performance as subballast
for railways tracks from a mechanical behaviour point of view. In addition, they can offer advantages
such as reducing greenhouse emissions, fuel consumption and waste as in the case of HWMA 100% RAP.
furthermore, the use of rubberized bituminous mixtures (DRA and WRA) make more durable sub-ballast
layer, at the same time that allow for waste recovery. Finally, the use of WMA, despite its performances
was slightly lower respect the others solutions studied, achieved acceptable results for its use as a subballast
layer. Moreover, it is a solution that guarantees to reduce pollution and energy consumption thanks
to its ability to reduce mixing and compaction temperatures.