An application of the S-VECD approach to analyse the performance of asphalt pavements with cold recycled materials

Pavements incorporating cold recycled material (CRM) mixtures are currently designed mostly using empirical methods. This study applies the mechanistic-based simplified viscoelastic continuum damage analysis and FlexPAVETM performance simulations to design pavements in which CRM mixtures produced using bitumen emulsion and cement replace either the aggregate base course or the lower part of the asphalt concrete (AC) surface course. A two-stage design procedure is adopted: the CRM course is modelled as viscoelastic and fatigue-prone until cracking (stage one) and as linear elastic afterwards (stage two). The results show that using a CRM course to replace the aggregate base significantly improves performance, reducing overall damage in the AC surfacing to about one-third. Replacing the lower part of the AC course with a CRM course provides equivalent performance, if a 25% to 50% thickness increase is adopted. These findings support the development of a mechanistic-based design approach for asphalt pavements, incorporating fatigue-prone CRM mixtures.