Evaluating the mechanical performance of Flemish bituminous mixtures containing RA by statistical analysis

Currently, reclaimed asphalt (RA) is considered as one of the most recyclable materials in the construction industry of the developed countries. The purpose of this paper is to investigate the effect of RA on manufactured mixtures in Flanders and to define a correlation between RA and mechanical performance through the statistical spectrum. In this study a statistical analysis was carried out on a dataset of 74 bituminous mixtures, certified in Flanders (2009-2016). A bivariate correlation analysis was used to determine the influential factors and the impact on the performance of mixtures. In addition, the determination of the effect of RA on major mechanical properties was evaluated by an independent-samples T-test analysis. Finally, a prediction model was fitted using the multiple linear regression analysis. The main result of the comparison within the mechanical properties showed that for this dataset the mixtures with RA exhibit at least equal mechanical properties compared to mixtures without RA. The correlation analysis provided insight on the influential factors of the mechanical properties, such as a significant linear correlation between binder properties (penetration and softening point) and mechanical properties (stiffness, fatigue and wheel rutting). Moreover, the multiple linear regression (MLR) analysis quantitatively described the influence of mix properties on mechanical properties.