Complete substitution of natural aggregates with industrial wastes in road subbase: A field study

Feasibility of complete substitution of natural aggregate by copper and steel industry wastes in subbase layer of flexible pavements was investigated by field monitoring for two years. Performance of nine test sections of three different thicknesses constructed using three waste mixes was compared with a conventional control section. The waste mixes used were flyash+5% lime, 80% flyash+20% granulated blast furnace slag, and 70% copper slag+30% flyash. Effect of pavement overloading and torrential rains on subbase moduli, service life and surface roughness were evaluated using falling weight deflectometer and bump integrator. Resilient moduli of core samples from pavement were compared with laboratory samples to estimate 'lab-to-field' effectiveness. With up to 140% higher service life, 23% lower surface roughness, 15% savings in construction cost and 50% reduction in annual greenhouse gas emissions, test sections exhibited superior structural, functional and economic perfor-mance compared to the control section with no environmental concerns.