Development of specifications and guidelines for hot in-place recycling in Finland—outline and framework

For 25 years, the hot in-place recycling (HIP-RC) has been the major pavement preservation technique in high volume roads in Finland, and currently it constitutes ca. 50% of all road construction expenditures. The cost is ca. half of the mill and fill overlay as only up to 25% new material is consumed. With least traffic disruption, it provides a quick refill of the rutted pavement, which is abraded due to the use of studded tires. Studded tires are used for mitigating icy roads conditions in the wintertime. However, the reduced maintenance funding has created a need to re-evaluate and better standardize the method. Therefore, a REMIX research project has been initiated, which focuses on the identification of best practices for the HIP-RC by reviewing prior construction records and their usability for the planning of future recycling and by developing enhanced performance criteria for the end product. The four-year project closely follows roads at different stages in their life cycle, which gives a unique opportunity to observe and study pavement surfaces recycled multiple times. This article presets outline and framework for the project and gives results from the initial stage of the project.