Waste materials and biproducts from various industries can be a good alternative source of pavement materials. This will reduce the demand for natural aggregates. Instead of dumping as landfill, using these materials in pavements will significantly contribute to obtaining climate neutrality and circular economy. However, based on the sources, the properties of these materials can vary widely. Knowledge and experience regarding the suitability and performance of these waste materials in pavements is not as extensive as conventional materials. Hence, prior to employing in pavement constructions, it is necessary to investigate the mechanical properties of these materials in a systematic manner and to create guidelines for their usage.
In this study, recycled materials from four different sources were investigated as alternatives for pavement constructions. Two of the materials were coarse fractions of the bottom ash from two incineration plants. The other two materials were crushed concrete from demolished constructions and material from road scalpings. Both laboratory and full-scale accelerated tests were conducted. The objectives were to compare their relative performances and to obtain and calibrate the material properties for further design using a pavement design tool ERAPave.
The laboratory investigations were based on repeated load triaxial (RLT) testing. From the RLT tests, the stiffness and permanent deformation properties as well as the model parameters used in ERAPave for each of these materials were evaluated.
For the full-scale accelerated tests, four instrumented test structures were built where all the layers were identical except for the subbase layers which were composed of each of the alternative materials. These structures were then tested employing a heavy vehicle simulator (HVS). During the passages of the wheel of the HVS, development of the surface rutting as well as deformations and stresses in the different layers were registered.
In both laboratory and full-scale tests, results indicated that the crushed concrete performed the best which is comparable to well-graded crushed rock aggregates. Material from road scalpings demonstrated the weakest performance followed by the two bottom ash materials.
Linköping: Statens väg- och transportforskningsinstitut , 2024. p. 425-426