The National Ready Mixed Concrete Association has published Version 4 of its industry-wide concrete EPD, the document specifiers and Buy Clean programs use as the baseline for what an average ready-mix product emits. It replaces Version 3.2 from 2022 and draws on 1,238 plants, up from 489.
NRMCA announced the new LCA and EPD on Oct. 14. The EPD itself is registered with the International EPD System, carries an Oct. 9 version date and is valid through October 2031.
What changed in the industry-wide concrete EPD
The product list grew from 72 mixes to 120, and it’s sorted more finely than before. Normal-weight concrete is now split into air-entrained and non-air-entrained versions from 2,500 to 5,000 psi. High-strength mixes run to 12,000 psi, and structural lightweight covers 3,000 to 5,000 psi. Each strength is modeled at eight cementitious blends, from straight portland cement up to 50% slag, plus a ternary mix with 20% fly ash and 30% slag.
Each product also comes with standard deviations, percentiles and confidence intervals, which earlier versions didn’t publish. That’s useful for producers checking their own plant-specific EPDs against the average, and NRMCA says producers have issued nearly 90,000 of those.
WAP Sustainability, based in Brentwood, Tennessee, developed the LCA and EPD on its Theta Concrete software. The work follows version 3.0 of NSF’s concrete product category rule, which the International EPD System accepted on July 29.
Embodied carbon numbers for ready-mix concrete
A national-average 4,000 psi non-air-entrained mix with no fly ash or slag comes in at 330 kg of CO2e per cubic meter, cradle to gate. Swap in 50% slag and it drops to 216 kg. Across all 120 products, results run from 168 kg to 745 kg, and cement accounts for 38% to 97% of the raw-material carbon depending on the blend.
Version 3.2 listed the comparable straight-cement 4,000 psi mix at 384 kg. That’s a 14% drop on paper, and it lines up with the move to portland-limestone cement, which by May was 96% of blended cement shipments. NRMCA presents the new numbers as confirmation that members are cutting carbon.
Read the comparison with care. The two versions use different PCRs and different global warming methods (TRACI 2.1 in Version 3.2, IPCC AR5 in Version 4), and the new EPD’s own text says declarations aren’t comparable unless those match. Some of the 14% is real. Some of it is method.
Old data, long shelf life
Timing is the other catch. NRMCA told producers in 2023 that it would revise the EPD that year. It didn’t land until October 2026, the primary data comes from calendar 2023 and 2024 operations, and the document stays valid until 2031. Late in its life, this baseline will describe plants as they ran seven or eight years earlier.
That cuts in producers’ favor. Low-carbon concrete specs often key their GWP limits to the industry average, and engineers are already pushing code changes aimed at embodied carbon. If plants kept cutting after 2024, an average built on older data is easier to beat than it looks, and agencies writing caps from Version 4 should expect plant-specific EPDs to clear them with room to spare.