Field application of recycled glass pozzolan for concrete

The inconsistent supply of fly ash and relatively high cost of slag as supplementary cementitious materials (SCMs) in the Northeastern United States is of concern to the concrete industry. Fly ash is a by-product from coal-burning plants that are shutting down or converting to natural gas, and slag is a residue from steel production mainly outside of the United States. With the goal of contributing significantly to the implementation of sustainable high-performance concrete, this study focuses on the evaluation of mixture designs using recycled post-consumer glass as SCM for concrete, for three mixtures with 20, 30, and 40% glass pozzolan as cement replacements, as well as two other comparable mixtures with 30% fly ash and 40% slag. Following laboratory characterizations for fresh and hardened properties, the mixtures with 20 and 40% glass pozzolan were selected for implementation in a sidewalk project in Queens, NY. The field work involved evaluations of mixture production, placement, finishing, curing, compressive strength, and development of maturity curves from data loggers in concrete. This study offers great potential for benefitting the concrete and glass recycling industries.