Low-clinker and low-binder strategies for sustainable precast concrete: From literature review to industrial validation

The decarbonization of precast concrete is primarily driven by the reduction of clinker factor and total binder content. However, their implementation is constrained by stringent early-age requirements and rheological properties associated with industrial production cycles. This paper presents a critical review of low-clinker and low-binder strategies for precast concrete, with specific focus on their interaction with hydration kinetics, rheological behavior and process constraints. The literature analysis highlights that clinker reduction and binder optimization affect, respectively, early-age strength development and fresh-state performance, making their combined application particularly challenging. Various technological solutions are discussed, including composite binders, hydration control through chemical activation (e.g. nucleation seeding and tailored accelerating admixtures), and rheological optimization in low-paste systems through advanced superplasticizer design and particle packing strategies. To complement the review, a full-scale industrial validation is presented. Two concrete mixtures based on limestone calcined clay cement (LC 3 )-type binders, reduced binder content and targeted accelerating admixtures were implemented in the production of prestressed beams and lightweight sandwich panels under standard plant conditions. The results confirm that early-age requirements can be satisfied within typical demolding times, without modifying the production process or compromising element quality, while reducing the cradle-to-gate GWP by 18% for the prestressed beams and 13% for the sandwich panels, with negligible cost variation. The combined analysis demonstrates that low-clinker, reduced-binder strategies are technically viable for precast applications when mix design is adapted to process-driven constraints.