Durable and sustainable overlay with ECC

While Portland cement concrete (PCC) overlay has been increasingly used as a rehabilitation technique for deteriorated PCC pavements in the last decade, reflective cracking places a major limit on its durability performance. The use of ultra ductile concrete named Engineered Cementitious Composite (ECC) should arrest such failure mode and greatly enhance the long term performance of the overlaid pavements. In this paper, we introduce and demonstrate this novel concept via experimental study on the reflective cracking resistance of small-scale ECC overlaid concrete beam. The ECC specimens totally eliminate the reflective cracking mode by developing extensive micro-cracks under flexural fatigue loading, in addition to a much enhanced MOR compared to controlled concrete specimen. Based on FEM analysis of the overlay system and fatigue performance of the ECC beam, a simplified design chart for ECC overlay is presented for use in practice and LCALCC analysis. The proposed ductile overlay approach should greatly enhance the durability and sustainability of the future pavement overlay