Ultra-low Carbon Concrete Trial

Global cement production is widely acknowledged to account for ~8% of anthropogenic carbon dioxide (“CO₂”) emissions*. While Byrne Bros. continues to use cement replacements, their potential to entirely replace CEM I (commonly known as Ordinary Portland Cement (“OPC”)) is limited. Accordingly, alternative technologies are required to further reduce the embodied CO₂e of concrete.

Working in collaboration with Wagners, Capital Concrete, OTB Concrete, Thornton Tomasetti and Canary Wharf Contractors, Byrne Bros. successfully poured our first trial of Wagner’s EFC^® at Canary Wharf’s new district, Wood Wharf on Tuesday 17^th March 2020.

Wagners’ EFC^® geopolymer concrete utilises a binder of chemically activated Supplementary Cementitious Materials, GGBS and PFA to eliminate the use of CEM I within concrete mixes. Capital Concrete provided a C40/50 EFC^® mix for the trial, which was used for blinding, and has allowed a range of plastic and hardened concrete testing to be completed, including consistency, development of strength, temperature and density.

When compared with a typical CEM IIIA C40/50 mix (510kg/m³ binder, 50% GGBS), the EFC^® mix resulted in a 45.6% (121.5kg/m³) decrease in embodied CO₂e**, and achieved an equivalent 28 day compressive strength of 62.5N/mm²***. Furthermore, the EFC^® mix accomplished a compressive strength of 18.8N/mm² after 1 day. This trial highlights the significant potential operational benefits and embodied CO₂e savings of Wagners’ EFC^®, particularly when replacing higher strength-grade CEM I based concrete.

Due to the promise of ultra-low carbon concretes, Byrne Bros. will continue to engage with our supply chain and consultants to maximise their use, and to help facilitate their progression to becoming a mainstream material.

_{*Chatham House Report, 2018, Making Concrete Change: Innovation in Low-carbon Cement and Concrete.}

_{**Calculated using Wagners’ data and data taken from the OPC product’s Environmental Product Declaration.}

_{***Compressive strength data provided by Holiday Concrete Testing.}