Synergistic effects of Nano-TiO₂ in GGBS-based low-clinker concrete: Mechanical performance, microstructural evolution, and life cycle assessment

The increase in Environmental burden and depletion of the natural resources associated with cement manufacturing has intensified alternative search options for concrete production without affecting his performance. While previous studies have individualistically examined nano-titanium dioxide (NT) or and ground granulated blast-furnace slag (GGBS) modified concretes, partial research has methodically studied their synergistic interface from both mechanistic and life-cycle sustainability perspectives. As a result, this study explored the combined impact of NT on the strength, microstructure, and sustainability of concrete. Owing to its extremely small size and photocatalytic properties, NT enhances hydration kinetics, refines the pore structure, and offers self-cleaning capabilities. GGBS contributes to long-term strength development and eco-efficiency through pozzolanic activity. Concrete mixtures were created by adding 2% NT with varying levels of GGBS replacement (10–50%) and were evaluated for their mechanical properties, durability, and environmental impact. Standard tests for compressive, split-tensile, and flexural strengths were conducted at 7, 28, and 90 d, along with SEM, XRD, and life cycle assessment (LCA) analyses. The results showed that NT significantly improved the early age strength owing to the nucleation and micro filler effects, whereas GGBS enhanced the long-term performance. The optimal mix, consisting of 2% NT with 30% GGBS (NCG30), achieved superior compressive strength (38.12 MPa at 28 days) and flexural performance compared to traditional concrete. Microstructural analyses confirmed the presence of refined hydration products and reduced porosity at optimal proportions. The LCA findings indicated a significant reduction in the relative global warming potential and resource depletion for NT–GGBS concrete, with NCG30 offering the best strength-to-cost and strength-to-GWP ratios. This research highlights that combining NT and GGBS leads to concrete that is high-performing, economical, and environmentally friendly. This combined approach offers a feasible solution to lessen dependence on cement, enhance durability, and minimize ecological impact, thus promoting a transition to more sustainable building practices.