Empa develops matrix for tailor-made asphalt

Roads are exposed to stresses including heavy trucks, heat, cold and rain. For this reason, researchers are developing road surfaces that can withstand theses stresses for as long as possible. However, no type of asphalt is perfect for every kind of road.   

“A busy road in a moderate climatic zone requires different characteristics than a rarely used mountain road that has to last even during the cold winter,” explained Empa in a statement.  

Asphalt is composed of rock of different grain sizes and the binder bitumen, a black sticky mass obtained from crude oil. Thanks to modern technologies, it can be produced to suit specific conditions. During the process, the manufacturer first defines what properties the asphalt should have and selects the ingredients in terms of quality and quantity. The finished asphalt mix is then artificially aged and tested for its desired properties, with improvements made and renewed testing undertaken should it not fulfil these requirements.

Empa researcher Martin Zaumanis has now developed a matrix that can help determine exactly how the asphalt must be improved to meet the desired characteristics. The matrix describes the influence of various parameters on six desired properties: resistance to ruts, moisture, thermal and load-induced cracks, rigidity and workability. It should help future asphalt designers to meet the properties of the road surface in as few steps as possible.