Friday 24 July 2020
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 17th 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.