Tests campaign analysis to evaluate the capability of fragmentation test to characterize recycled asphalt pavement (RAP) material

Cold and hot recycling of reclaimed asphalt pavement (RAP) is increasingly gaining in popularity worldwide due to the need to increase the sustainability of asphalt pavement, both from environmental and economic perspectives. Despite the increasing of use of these techniques, we are still faced with the problem of correctly characterizing RAP. In the framework of the RILEM TC 237-SIB TG6, a Round Robin Test (RRT) was performed in order to evaluate the capacity of the fragmentation test to characterize RAP materials. A total of 5 laboratories located in 4 different countries were involved in the testing program. This paper focuses on the presentation of the fragmentation test method and the results of the RRT performed on different sources of RAP. To differentiate RAP materials in terms of size alteration vulnerability, fragmentation tests were performed at three different temperatures (5, 20 and 40 °C) on different sources of RAP. Fragmentation testing consists in evaluating the amount of materials passing through a control sieve of a coarse uniform RAP material after a fixed series of strokes carried out with a normalized falling mass. Results show that fragmentation is reduced when the testing temperature increases. Fragmentation tests performed on natural aggregates indicate that they do not vary with the testing temperature, and such test results are a function of the amount of foreign matter in the RAP. The results also show that the test is suitable for differentiating RAP materials from different sources.