Paragraphs Environmental Design

Embodied Carbon of Concrete Mixes at Comparable Strength: An Analysis of Public Environmental Product Declarations

Original Research · Environmental Design · 2025, Volume 3, Issue 3: 98–115

DOI: 10.5281/zenodo.24162475

Adrian Luchini*

Raymond E. Maritz Professor of Architecture Emeritus, Washington University in St. Louis

*Correspondence: adrianluchini87@gmail.com

Received: May 2025 | Accepted: May 2025 | Published: July 2025

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Abstract

Comparing concrete environmental product declarations requires a defensible relationship between the quantity of material assessed and the performance expected from it. Compressive strength provides an accessible comparison variable, but identical strength labels do not establish identical construction requirements or service lives. This article presents an original descriptive reanalysis of two public declarations published before 1 December 2024: 48 normal-weight mixture scenarios in the National Ready Mixed Concrete Association’s 2022 industry-average declaration and all 29 mixtures in the DuPont plant table of CalPortland’s 2019 Washington declaration. The documents are analyzed separately because their product category rule versions and data contexts differ. The primary measure is cradle-to-gate global warming potential in kilograms of carbon dioxide equivalent per cubic metre. Within the six industry-model strength classes, the difference between the modeled zero-supplementary-cementitious-material reference and the lowest reported scenario is 36.07–39.18%, equivalent to 100.84–224.95 kg CO₂e/m³. Conversely, differences between the 40% fly-ash and 40% slag scenarios remain below 0.1%. The producer’s 4,000-psi and 5,000-psi groups exhibit substantial declared dispersion, but missing mixture-level performance information prevents interpreting those ranges as available substitution savings. Original calculations distinguish absolute carbon headroom, baseline-dependent percentage reductions, and deterministic ranking-reversal thresholds from statistical uncertainty. Dividing global warming potential by nominal strength adds no ranking information within an exact strength group and can conceal rising emissions per cubic metre across groups. The synthesis is a staged comparison method: establish accounting compatibility, establish application-specific performance eligibility, and then evaluate carbon differences at the relevant decision scale. Public declarations support useful screening decisions when their evidential limits remain attached to the results.

Keywords: concrete; embodied carbon; environmental product declaration; compressive strength; supplementary cementitious materials; comparative life cycle assessment

Citation

Luchini A. (2025). Embodied Carbon of Concrete Mixes at Comparable Strength: An Analysis of Public Environmental Product Declarations. Paragraphs Environmental Design, 3(3), 98–115. DOI: 10.5281/zenodo.24162475

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