One of the main aims of C-Probe’s technology is creating sustainable resilience for the built environment through corrosion mitigation. A significant part of this is reusing and recycling existing infrastructure, retaining vital embodied and operational carbon and preventing the release of emissions through construction. Embodied carbon is becoming an increasing priority within the built environment, especially as the UK Government will be considering how they can tackle it within their upcoming building strategy. Although emissions can be decreased using low carbon build materials and methods, it is restoring our existing building stock that needs to become a higher priority in the lead up to NetZero and COP26.
In fact, The Architects’ Journal has been recently campaigning this issue whilst urging ministers to insist that the existing buildings are refurbished, rather than demolished. The journal has calculated that the difference between expanding the old buildings and replacing them amounts to 19,180 tonnes of CO2 – that’s the equivalent of 4,171 passenger cars driven for a year.
So, why is embodied carbon so important? Embodied carbon is the carbon footprint of a material and is often measured from cradle to gate. Embodied carbon will consider how many greenhouse gases (GHGs) are released throughout the supply chain and includes the extraction of materials from the ground, transport, refining, processing, assembly, in-use (of the product) and finally its end-of-life profile.
The release of harmful carbon can be caused by structural corrosion, an issue that is not highlighted enough within the industry. Existing Grade II buildings and infrastructure such as bridges and piers are under constant repair cycles, and this is due to moisture ingress to the external cover that can cause damage by initiating corrosion as rust products expand 8-10x the volume of metal loss at the surface. NACE found in one of their studies that corrosion is the cause of 70% of infrastructure damage in western economies. C-Probe looks to tackle this common problem through their low carbon cement products and whole life smart monitoring and control systems which are retrofitted to existing structures, both of which tackle embodied carbon simultaneously.
The manufacture and implementation of materials are key to the amount of embodied carbon within a structure. LoCem® is used by C-Probe as an alternative to Portland cement but is specifically formulated to act as an impressed current cathodic protection (ICCP) anode cement to offer whole life control of corrosion in all structures not possible with Portland cements. These novel binders are repurposed industrial waste by-products with no heat offering during production giving over 90% CO2e saving compared to CEM I. From this low emissions platform, mix designs have been formulated as products with the objective of ease of installation using traditional construction methods by contractors familiar with using cementitious materials.
The use of LoCem® in both restoration and new construction helps to effectively preserve the amount of embodied carbon within a structure, whilst offering higher resilience for a very long time. To put in context of how effective C-Probe’s products are in retaining embodied carbon, here are key calculations from an upcoming project of the repair of a large concrete plaza deck:
• The deck slabs have a footprint of some 40,000m3 with 18,500m3 of some 600mm thickness requiring full or partial demolition and reconstruction before C-Probe’s corrosion protection are installed to the full project.
• This represents an initial loss of embodied carbon - based on literature figures for Portland concrete and steel at 430kg CO2e/m3 - of 4,773 tonnes of CO2e.
• If the project had been undertaken before the damage had got this significant, then all this embodied carbon would have been saved.
• Without the corrosion protection then the remaining in-tact deck of 21,500m3 or 5,547 tonnes of CO2e would be at risk but will now be saved.
• The full project will receive corrosion control that preserves 10,320 tonnes of CO2e and futureproofs the property by online control and performance reporting for its whole life.
C-Probe’s main innovation is not only sustainable in its manufacture, but also in the way it restores infrastructure. Using LoCem® as both an anode and repair material prevents deconstruction of existing structures, and partnering this with embedded sensors and service life tracking allows owners have full control in preventing future corrosion issues indefinitely.
Blending the sustainable benefits of AACM’s and infrastructure control technology will help to eventually replace conventional construction chemicals for repairing structures and replace concrete mix designs for new build. Overall, it will help to provide a continuous improvement path for a low carbon future in the built environment.