Evolution with Time of the Thermomechanical Behaviour of Mixtures Containing Crumb Rubber Added by Dry Process

This study was conducted to assess the time evolution of the linear viscoelastic behaviour of bituminous mixtures containing crumb rubber added by dry process. For this purpose, three mixtures containing 0% or 4% of rubber and with neat 35/50 pen grade or SBS-modified bitumen were manufactured and stored for 15 months before being subjected to complex modulus tests. The results were compared to those obtained from a previous study that investigated the linear viscoelastic behaviour of identical materials but tested shortly after their production. The outcomes reveal no significant evolution for mixtures with neat 35/50 pen grade bitumen and 4% of crumb rubber. However, a potential evolution (ageing or bitumen-rubber interaction) is observed for mixtures with 4% of crumb rubber and SBS-modified bitumen. This study provides valuable insights into the long-term performance of rubber-modified bituminous mixtures, highlighting the need for further investigation into the factors influencing the material’s behaviour over time.