What is one challenge of using recycled materials in new asphalt mixes?

Using recycled materials in new asphalt mixes introduces the challenge of potential variability in material properties. This is primarily due to the fact that recycled materials, such as reclaimed asphalt pavement (RAP), may come from various sources and may have different aging, gradation, and binder content compared to virgin materials. As a result, when these recycled components are blended into new mixes, they can lead to inconsistencies in performance characteristics, such as strength, workability, and durability.

This variability can complicate the mix design process and affect the overall quality of the asphalt pavement. Engineers and contractors need to be particularly diligent in conducting proper testing and adjustments to ensure that the mix meets the required specifications and performs adequately under anticipated loads and environmental conditions. By understanding and addressing these potential variations, paving professionals can effectively incorporate recycled materials, contributing to sustainability while maintaining the integrity of the asphalt pavement.