– Our goal is to develop a simulation method for loading, spreading and compaction of unbound aggregate materials in road construction, a method that is ultimately intended to contribute to improving the Swedish road network, with increased service life and reduced maintenance, higher cost efficiency and improved environmental aspects. The results from the initial part of the project are so interesting that we have developed a wider application for funding for the continuation and expansion of the project. And fortunately, Vinnova / InfraSweden 2030 has approved our application for a continuation until 2021, so step two is now running.
This is how Johannes Quist, responsible researcher at Fraunhofer-Chalmers Centre, currently summarizes the project DigiRoad.
The initial project, called "Simulation and Visualization of Road Construction", was a collaboration between the Chalmers Area of Advance Building Futures, Fraunhofer Chalmers Centre for Industrial Mathematics (FCC) and the company NCC AB. With the new research application, the project has been renamed "DigiRoad", and additional partners have been added to form a consortium, in addition to the previous partners, Volvo CE and Dynapac as well as the research group Chalmers Rock Processing Systems are now also a part of the project team.
In road construction, the road body is usually built up of several, bound and unbound layers of rock material. Depending on how these layers are constructed and on the nature of the rock material, the characteristics of the road, such as bearing capacity, functionality and life expectancy, can vary and be varied. The processes are studied systematically, and areas that are investigated include the thickness of the different layers, the size distribution and segregation effects, and the material to be used and how the compaction of the material should be carried out. Today, planning takes place on a more general level.
A tool making it possible to evaluate in advance by simulation
The aim of the project is a tool that enables simulation in advance of sub-processes in the road construction process, in order to enable concrete measures to be made that can streamline Swedish road production, both in terms of quality and cost.
– To evaluate segregation and packing behaviour experimentally has always been difficult," Johannes continues. The evaluations are today limited to what is physically measurable in the field. The purpose of the ongoing research project is to develop a tool that allows for advance simulation of the process, and with a very high resolution - down on the level of individual particles.
The simulation method used is Discrete Element Method (DEM), or "Particle Simulation" as Johannes calls it in everyday language.
– We hope to be able to develop road construction technology on a number of different levels within the consortium. The capability is not limited to simulating for optimization of the unbound aggregate layers, we also look at possibilities for optimizing machine geometry, both in terms of quantity and quality, for example in the handling and transport of the rock material.
Johannes Quist, Fraunhofer Chalmers Centre.
In the first phase of the project, we worked mainly in digital environments, but in stage two of the project, the idea is to proceed with full scale testing, using full-scale machinery and validating the method through experiments in the field.
We who work with the project see the great potential and usability of the method, and we are all very much looking forward to the continuation of the project
and the tough challenges that await.
Video: Fraunhofer Chalmers Centre
Text: Agneta Olsson