Reducing carbon footprint through binder content optimization in durable performance-based concrete overlays

Abstract Common failure mechanisms in bridge deck overlays include early-age cracking, chloride ingress, and degradation from harsh environmental conditions. To address these issues, performance-based, durable, and sustainable concrete mixtures are needed. This study evaluated eight concrete overlay mixtures designed to improve durability, reduce early-age cracking, and extend the service life of bridge deck overlays in Texas, while also reducing cement and water demand. The mixtures incorporated three cement types, ordinary portland cement (OPC), portland limestone cement (PLC), and calcium sulfoaluminate cement (CSA), combined with supplementary materials such as fly ash, silica fume, latex, and polymer additives. Aggregate structure optimization was performed using the Power 45 and Tarantula methods to minimize paste content and enhance packing density. Fresh and hardened properties of the mixtures were assessed at multiple ages. Key findings show that CSA cement mixtures achieved the fastest initial setting (3.5 h), and the highest early-age compressive strength (45.2 MPa at 7 days). The addition of latex delayed the setting time by only 0.5 h but significantly improved tensile strength by up to 18%. PLC cement mixtures containing fly ash exhibited improved workability (slump increase from 75 to 110 mm) and extended setting times by 2–3 h, while combining fly ash with silica fume refined the pore structure and reduced chloride migration by up to 52% compared to control OPC mixtures. CSA-polymer mixtures demonstrated the highest durability, achieving a 56-day surface resistivity increase of 186.8% and the lowest chloride migration coefficient (2.42 × 10⁻ 10 m2/s) compared to conventional OPC mixtures.