Abstract
Concrete mix designs are evaluated against multiple technical and environmental criteria, including consistency, compressive strength, water–cement ratio, durability requirements, cement content and global warming potential (GWP). This study focuses on two resource- and climate-related quantities: cement content and GWP per cubic metre. Although both are relevant, they do not indicate the amount of cement or associated GWP per unit of achieved compressive strength. The proposed indicators are therefore intended as supplementary screening measures and do not provide evidence of compliance with durability or other technical requirements. This study proposes and evaluates a paired strength-normalised screening approach based on two indicators: cement intensity, = /,, and GWP intensity, = /,, where is the specified assessment age. The experimental assessment covered six medium-workability concrete mixtures designed for target compressive strengths of 35, 40 and 45 MPa. At each target-strength level, one composition was proportioned using the modified Bolomey three-equation method, an empirical procedure combining a strength–water–cement-ratio relationship, water-demand calculation and absolute-volume balance, while the corresponding composition was proportioned using Abrams’ law. All mixtures were prepared using CEM I 42.5 R, rounded natural aggregates and water, without chemical admixtures or separately added supplementary cementitious materials. Six 150 × 150 × 150 mm cube specimens were cast from each mixture and tested at 28 days; therefore, t = 28 days for the experimental dataset analysed in this study. The environmental assessment was recalculated using a consistent scenario-based cradle-to-gate boundary comprising constituent production (A1), transport to the concrete plant (A2) and concrete-mix production (A3). All six mixtures achieved their target compressive strengths, but substantial differences were observed in the amounts of cement and A1–A3 GWP associated with one MPa of measured mean strength. The largest difference occurred at the target-strength level of 45 MPa, where the composition designed using the modified Bolomey three-equation method exhibited approximately 80% higher cement The indicators identify concrete compositions in which the achieved strength is associated with comparatively high cement consumption or A1–A3 GWP. However, low or values do not demonstrate that a composition is technically acceptable or durable. The indicators should therefore supplement, rather than replace, verification of strength, workability, water–cement ratio, exposure-class requirements and durability performance.