A digital design method for asphalt mixtures that incorporates aggregate geometry

• Published in: Construction & building materials 2024-02, Vol.416, p.135281, Article 135281
• Main Authors: Awuah, Frank K.A., Garcia-Hernandez, Alvaro, Valentin, Jan
• Format: Article
• Language: English
• Subjects: 3D modelling; Aggregate geometry; Asphalt mixtures; Bitumen; Digital design; Marshall test; Mastic; Workability
• ISSN: 0950-0618; 1879-0526
• DOI: 10.1016/j.conbuildmat.2024.135281

This paper presents a new Data-Driven digital method for selecting aggregates and bitumen content in hot mix asphalts (HMA) to achieve desired properties such as air voids content, workability, Marshall stability, and Marshall flow through a streamlined process. The proposed method consists of three steps: first, Dynamic Image Analysis is used to extract the geometric characteristics of the aggregates in asphalt mixtures. Second, physics engine software is used to assist estimating the number of aggregates and volume of mastic (bitumen, filler, and aggregates with Min Feret < 2 mm) in a fixed 250 g of asphalt mixtures. The generated number of aggregates and volume of mastic correspond to the aggregate gradation and bitumen content in the mixture. Third, the number of aggregates and volume of mastic that meet the desired properties are obtained based on correlations between the air voids content, workability, Marshall stability, Marshall flow, and the number of aggregates and volume of mastic. The proposed method achieved a 94% predictive accuracy for nine mixtures with consistent aggregate and bitumen. However, in a sensitivity analysis involving diverse asphalt mixtures, the predictive accuracy decreased to 78%. The authors have demonstrated that the number of aggregates, informed by their shapes, and volume of mastic significantly influence HMA performance and should be carefully controlled in future asphalt mix design, especially in creating realistic digital HMA representations. The proposed digital approach is expected to minimise the need for time-consuming and laborious physical and mechanical tests to determine the properties of new asphalt mixtures. [Display omitted] •Realistic aggregate gradations have been digitally generated in a physics engine software to design asphalt mixtures quickly.•These gradations fully incorporate the geometry of constituent aggregates.•The new digital design method achieved 94% accuracy in predicting the properties of their real counterparts.•3D models are generated to visualise aggregate distribution in designed mixtures before physical manufacturing begins.•The method has the potential to be utilised by autonomous machines for rapidly selecting asphalt recipes for road repairs.