Summary
- Brett Group confirms Capital Concrete designed, tested and supplied foundation mixes for a major East London data centre, working with McLaren and Keltbray.
- The supplier says much of the concrete was specified as DC4 for sulphate-bearing ground, with about 70% cement replacement by GGBS in some mixes.
- Capital also reports using CarbonCure in its standard mixes, but provides no independently verified project-wide embodied-carbon saving.
Capital Concrete has detailed the specialist mixes it designed and supplied for piling and foundation work at a major East London data centre project, including concrete specified for aggressive ground conditions and selected formulations with approximately 70% cement replacement using ground granulated blast-furnace slag (GGBS).
Parent company Brett Group says Capital Concrete developed and tested the mixes alongside McLaren Construction and specialist contractor Keltbray. A separate construction trade report identifies the project as Ada Infrastructure‘s Docklands campus in the Royal Docks. Ada confirms construction began in February on the first of three planned data centre buildings at the site.
Capital says much of the supplied material was specified as DC4 concrete to withstand challenging sulphate ground conditions. Some applications replace approximately 70% of the cement with GGBS, a supplementary cementitious material produced from ironmaking slag. The figure concerns selected mixes, not every foundation element or the total volume of concrete placed across the campus.
The developer describes the completed campus as providing 210MW of capacity across three 70MW buildings, with the first building expected to be ready for service in mid-2028. That is planned facility capacity, not an operating load or confirmation that all three stages have been commissioned. The material announcement concerns work underway at the construction stage.
Ground conditions shape the foundation specification
DC4 is a design chemical class used in British concrete specification for exposure to aggressive ground conditions. It reflects the chemical-resistance requirement for a concrete mix; it is not a new data centre material category. Concrete in piles and other buried structural elements must satisfy the ground investigation and the relevant structural specification before being accepted for use.
GGBS replaces part of the Portland cement content in a binder system. Depending on the formulation and exposure, higher replacement proportions can improve resistance to certain chemical attacks while reducing the proportion of clinker-intensive cement. Strength development, curing conditions and early-age performance still have to meet the construction programme. High GGBS content is therefore a design decision subject to testing rather than evidence that one recipe will suit every element.
Capital says its laboratory and quality-control procedures were used to prepare mixes for different piling and foundation applications. It supplied the concrete from its Silvertown plant, near the Royal Docks construction site. Local batching reduces the journey between production and placement, although the company has not published a quantified transport-emissions saving for this contract. Construction trade reporting rates the Silvertown wet-batch plant at 200 cubic metres per hour. That describes the plant’s nominal production capacity, not the quantity of concrete actually delivered to Ada’s site.
The reported groundworks involve continuous flight auger piling by Keltbray and bi-modulus column work by Menard. These methods perform different ground-support functions and should not be conflated with a novel concrete technology. Their specification depends on load transfer, ground conditions and settlement limits rather than the eventual use of the buildings for computing.
Lower-carbon claims remain supplier-reported
Brett Group also says Capital incorporated CarbonCure technology into its standard concrete mixes associated with the project. The process introduces captured carbon dioxide during batching and is designed to mineralise it in the concrete. That is separate from the substitution of GGBS for Portland cement, and the two approaches cannot be assumed to provide additive carbon savings without a consistent assessment of the final mix.
The supplier states that its high-GGBS formulations reduce embodied carbon compared with conventional mixes. However, it has not provided a quantified project-wide result, delivery volumes by mix, an independently verified lifecycle assessment or a baseline against which the overall saving can be calculated. Describing the specification as lower carbon is supportable as the supplier’s account; assigning a precise percentage reduction to the entire campus would not be.
Ada has separately identified lower-carbon energy and environmental features in its campus design, alongside air- and liquid-cooled computing infrastructure. The foundation mix selection is one element of a much larger construction programme involving buildings, power equipment and supporting infrastructure. The concrete specification does not establish the site’s eventual operational energy efficiency.
The confirmed supplier role, DC4 requirements and selected GGBS ratios provide a practical account of how ground conditions and material choices are being addressed during construction. The full structural and environmental performance of the work will depend on the tested mixes and completed site programme rather than supplier claims alone.
