UCD School of Civil, Structural and Environmental Engineering

• Developing the coupled Falling Weight Deflectometer test for determining railway foundation integrity
• Recycled Waste in Highway Design and Construction
• Design of Stone Mastic Asphalt and Thin Surfacing Materials for Irish Roads

Developing the coupled Falling Weight Deflectometer test for determining railway foundation integrity
Amanda Gibney, Paul Fanning, Prithvi Raju Mandapalli

Funded by: Enterprise Ireland Innovation Partnerships Scheme, Company Partner: Pavement Management Services Ltd.

This research project is exploring the technical viability of the Coupled Falling Weight Deflectometer test, to assess the quality of rail foundations. An assessment of rail foundation quality is essential to determine the both the load capacity and safe train speed of railway systems. Earlier research has demonstrated the applicability of the Falling Weight Deflectometer (FWD) test to assess rail foundations only when the stiff rails have been detached from the underlying sleepers. Significant time and labour costs are associated with unclipping the rails from the sleepers, limiting the practical applicability of the test. In the proposed Coupled FWD test the rail and sleeper will remain attached. This new test procedure will be quicker, cheaper and more convenient than the current approach. The new system including the rail is, however, more complex and research is being carried out to assess whether the test can still yield accurate information about the foundation conditions. If found technically viable the industrial partner for the proposed project (PMS) would implement the method to compete for rail testing contracts. Policy makers across Europe are committed to developing rail infrastructure so the industrial partner is confident that a market exists for this test method.

Recycled Waste in Highway Design and Construction
Amanda Gibney, Michael Gilchrist, Ciaran McNally, Tom Webster, Amir Tabakovic, Donnchadh Casey, Lorraine Fitzsimons

Funded by: Enterprise Ireland Advanced Technologies Research Programme

Each year 2.7 million tonnes of construction waste are consigned to landfill, despite the inherent potential of large quantities of this waste to perform a role as part of a flexible pavement system. This project offers a solution for this waste management problem through the introduction of holistically sustainable highway construction methods. Selected waste streams are being characterized by their physical and mechanical properties and their performance assessed through laboratory testing. Constitutive models are being developed which will be used to predict in-service response. Full scale field testing is also being undertaken using instrumented road sections constructed using recycled materials.

Design of Stone Mastic Asphalt and Thin Surfacing Materials for Irish Roads
Amanda Gibney, Tom Webster, Caroline Butler

Funded by: Enterprise Ireland

Stone Mastic Asphalt (SMA) is a relative newcomer on the bituminous materials scene in Ireland although it has been in use in Germany for the past twenty years. From wheel tracking tests undertaken at UCD the superior resistance of SMA to permanent deformation has been confirmed without doubt in comparison to Hot Rolled Asphalt mixes. A number of issues including mix design, binder drainage the use of fibres and the use of polymer modified binders in the Irish context have been investigated in this project. In addition the development of surface texture over time is being monitored using a full scale on-site trial section.