Sustainable Pavement Overlays Using Engineered Cementitious Composites

Abstract

──────────────── ─────── Abstract: Contributing nearly 5% of global anthropogenic greenhouse emissions through cement production alone, the concrete industry is a major contributor to global climate change. Automobiles and trucks that use concrete transportation infrastructure release another 30% of anthropogenic greenhouse emissions. Along with these atmospheric emissions, the construction, repair, and rehabilitation of concrete pavements rely on the production and flow of large quantities of concrete material and its constituents. To reduce environmental impact and improve the sustainability of pavement overlay systems, a class of materials called Engineered Cementitious Composites (ECC) is introduced to construct more sustainable, durable rigid pavement overlays. ECC overlays are designed to enhance sustainability in two ways. First, "greener" ECC materials incorporate high volumes of industrial waste to reduce the environmental impacts of material production. Fundamental micromechanics carefully guide this green material design to maintain pseudo-strain hardening material behavior under tension. This ductile behavior, over 500 times greater than conventional concrete, is critical to the second mechanism for sustainability enhancement. The ductility of ECC suppresses reflective cracking, a major cause of premature overlay failure, thereby increasing durability and reducing life-cycle maintenance. By incorporating industrial waste, over 70% of ECC virgin constituents have been replaced without reducing critical mechanical performance characteristics. When coupled with a possible 50% reduction in overlay thickness and extension of service life as compared to conventional concrete overlays, significant sustainability improvements have been modeled. These improvements are quantitatively measured using life cycle cost and life cycle assessment techniques.