LC³-Based Concrete with High Recycled Sand Content: Unveiling its Mechanical and Durability Potential

Developing green concrete with the employment of recycled fine aggregate (RFA) and limestone calcined Clay cement (LC³) could be a promising and economical method for the reduction of the environmental impact of buildings, by reducing CO₂ emission related to cement production and providing a viable alternative to natural resource depletion. This study was carried out to examine the mechanical and physical properties of LC³–based concrete, using different proportions of limestone, calcined clay, and cement clinker, with 100% natural coarse aggregates and 50 vol% of RFA substitution. The fresh state behavior was evaluated by the slump test, and the target slump was obtained by adjusting the superplasticizer dosage. The 28-day mechanical and durability properties including compressive strength, water absorption and capillary water absorption rate of different concretes were investigated. The results highlight that LC³ binders show better mechanical properties than reference commercial cement with both natural and recycled sands. Considering the superior mechanical properties and environmental advantages, combining LC³ binders with RFA for concrete production seems an effective approach for a sustainable development of the construction industry.