Nominee
Ultra-low GWP structural concrete mix designs
Category
Innovative Product or Service
Description
In 2022, Miller & Long produced ultra-low embodied carbon structural concrete mixes for use on our commercial projects. These mixes utilize a ternary blend of Portland Limestone Cement, Slag, and Pozzotive® Ground Glass Pozzolan (GGP) as well as a sophisticated blend of admixtures to allow them to act like normal concrete mixes in strength gain and workability. These mixes all have at least a 50% replacement and at least a 40%-60% improvement in Global Warming Potential against any baseline with room for improvement.
These proprietary mixes have been tested in labs for two years running and we’re continually making improvements to ensure maximum GWP reductions and performance.
We’re utilizing these mixes on two projects currently with three more starting by mid-2023.
Miller & Long is an NRMCA member.
Evidence
Preliminary EPDs for the mixes run in the low 190s (kg CO2) for 4000 psi to the low 200s for high strength mixes. The values for Pozzotive® alone are just above 5 kg CO2 in each mix design even considering a significant distance for truck freight. Because these mixes are produced at one of Miller & Long’s portable batch plant sites, there are no EPDs yet available for them. However, preliminary values have been provided by ClimateEarth and will be validated in 2023.
These proprietary mixes have been placed on two projects and even achieved the required strength results for 3-day stripping elevated slab elements (3750 psi for 5000 psi required) as well as all other structural elements in the projects thus far (up to and including 10,000 psi for vertical elements).
See pictures of Pozzotive® samples and slab placement at a current project where these mixes are being utilized.
Images (click to expand)
