Application of greener engineered cementitious composites for sustainable pavement overlay design

Pavement rehabilitation is a subject that has continuously worried transport authorities. Many old pavements in service nowadays are approaching the end of their design service lives and are in dire need of major repair to continue serving. Both conventional Portland cement concrete and asphalt have been used in the rehabilitation of existing deteriorated concrete and hot-mix asphalt pavements. Although these solutions may provide a reasonable performance when well designed and constructed, a critical limitation on their service life is the occurrence of reflective cracks. None of the current repair techniques can totally eliminate this problem. However, recent data suggests that some advanced fiber reinforced composites, made with polimeric microfibers, known as Engineered Cementitious Composites (ECC), may advantageously be used to create a thin, durable and cost-effective overlay. This paper focuses on the development and characterisation of an ECC mixture made with high tenacity polypropylene fibers, which are less costly than PVA fibers originally used to develop ECCs. An experimental investigation was combined with a finite element analysis, in order to assess the performance of this new material, which is marked by its strain hardening behavior. Furthermore, a Life Cycle Assessment (LCA) exercise and a Life Cycle Cost (LCC) analysis were carried out to demonstrate that this kind of rehabilitation solution leads to a more sustainable overlay design.