Development of sustainable, high strength slag based alkali activated pavement quality concrete using agro-industrial wastes: properties and life cycle analysis
Akhila Sheshadri, Shriram Marathe, Łukasz Sadowski
Abstract
Alkali-activated binder-based composites offer a sustainable alternative to cement-based systems, giving a conservational approach. This research incorporated rice-husk ash (RHA) and waste foundry sand (WFS) into ground-granulated-blast-furnace slag (GGBS)-based alkali-activated high-end pavement-quality concretes, optimising with air-curing for expressways, freeways and runway applications. This study promotes sustainable construction by efficiently utilising agro-industrial wastes (i.e., RHA, GGBS and WFS) promoting a global initiative to decrease environmental impact and to adopt eco-friendly pavement construction methods. This study systematically substitutes the primary binder-GGBS with RHA at 5% intervals. The binder was alkali-activated using measured amounts of liquid sodium silicate and sodium hydroxide flakes prepared at an activator modulus (Ms) of 1.25 by maintaining the sodium oxide dosage of 4.0% with respect to the total binder. In particular, 15% RHA (with 85% GGBS) and 20% WFS (with 80% river sand) satisfy mechanical design standards for workability and strength. A comprehensive life cycle analysis using extensive literature support assesses the environmental impact and sustainability of developed pavement quality composites, showing over 70% less energy use than Portland cement-based pavement mixes. Therefore, employing RHA and WFS in air-cured alkali-activated composite manufacture shows that agro-industrial waste components may be used to make sustainable, cost-effective pavement construction. This study effectively advocates for a shift towards environmentally responsible pavement construction, contributing to a greener, more sustainable future in concrete pavement engineering.