Cold Recycling in Major Highway Rehabilitation: A Case Study from Greece on Design and Performance

Abstract: GEK TERNA S.A , in collaboration with Loudon International (Loudons) successfully executed a Cold In-Place Recycling project, utilising Bitumen Stabilised Material (BSM) Technology along the E-65 Highway near Lamia and Kamena Vourla in Greece in July 2023. The project included two main sections, with the larger portion concentrated near Kamena Vourla (km180+000 to km185+000) and a smaller segment adjacent to Lamia (km212+000 and km214+500). The design provisioned for 30 million E80’s and the in-situ recycling was confined to the heavier trafficked slow lanes of both the left- and right-branches.

The primary goal of this initiative was to construct a project utilising the existing asphalt and granular support layers for the creation of a new non-continuously bound BSM base layer, as an alternative to the conventional rehabilitation solution using mill and replace Hot Mix Asphalt (HMA). The completed cold recycling pavement had to comply with the Concessions strict KPI’s requirements, and the early life performance of the road has been measured numerous since construction was completed. This data allows excellent results and insight into the performance of cold recycling on major highways. It confirms that cold recycling solutions can effectively compete with the performance of HMA while reducing the costs and material requirements.

As a supplementary outcome the project's implementation of BSM technology had various eco-friendly benefits, resulting in noteworthy natural resource and carbon emission savings.

In the road construction industry, prioritising carbon emission reduction and the reuse of construction materials holds significant importance. Firstly, by reducing carbon emissions, the industry can contribute to tackling climate change and while aligning itself for compliance with the stringent regulatory and policy frameworks set by various Government Departments. Cold recycling, and BSM specifically, has significant potential to support the industry's role in achieving global sustainability goals, while also reflecting the principles of a circular economy.

This paper seeks to provide a summary of the project's design approach, the early life measured performance and the realised benefits of using cold recycling technology, with a specific focus on comparing the conventional HMA rehabilitation approach to BSM and cold in-place recycling. Through this comparative analysis, it was possible to estimate and report the amount of CO2 savings that was achieved on this specific project, confirming the potential benefits of cold recycling technology.