Measuring aggregate and binder interaction by way of mixture tests before and after field ageing

Abstract

Mixture properties were measured before and after field ageing to evaluate how aggregates, binder and environmental effects interact. To isolate these effects, very simple mixes (usually comprising one aggregate source and one binder) were designed and tested. The results showed that clear differences existed before and after field ageing where the same binder was utilised with different aggregates. Aggregate effects were magnified by field ageing. The results agree with a literature review that has documented aggregates' influence in response to environmental effects such as ageing for many years. When combined with the literature reviewed, the data collected should help ongoing discussions within the asphalt industry related to mixture testing and how to capture environmental effects/ageing. To truly capture in-service conditions, mixture conditioning that can simulate the simultaneous effects of the environment, aggregates and binder is likely to be the most effective approach based on the data reported in this paper. This is especially true today where mixtures are often very complex and contain many virgin and post-consumer ingredients.