Carbon-storing concrete floor reaches commercial scale

Holcim, Paebbl, and GOLDBECK have delivered a commercial-scale industrial floor slab in southern Germany using carbon-storing ready-mix concrete.

The 420 sq m floor was installed at an e-commerce logistics facility and used a Holcim concrete mix incorporating Paebbl Rebond, a supplementary cementitious material produced through accelerated CO2 mineralisation. The mix replaced 15% of traditional cement and reduced embodied carbon by 13% compared with the reference CEM II/B-M mix.

The final concrete met the full C30/37 strength specification and was placed using standard construction methods. The project also permanently stored 886kg of CO2 through mineralisation across the slab area, while moving from concept to implementation in less than six months.

Paebbl Rebond is produced by turning captured CO2 into a stable mineral powder composed primarily of magnesium carbonate and silicon dioxide. Used as a partial cement replacement, the material is designed to reduce the carbon intensity of concrete while locking carbon into solid form.

Holcim’s Offenburg plant produced the ready-mix concrete, integrating Rebond into a standard mix design. Laboratory testing was carried out at the Holcim Innovation Center in Lyon, with plant trials in southern Germany assessing workability, air content, bleeding behaviour, and practical handling. GOLDBECK managed the construction and placement, confirming that the mix behaved in line with standard site requirements, including setting time and finishing behaviour.

The slab takes carbon-storing concrete out of the narrow category of trial material and into a commercial construction sequence. It was not delivered as a specialist laboratory pour requiring a different site process. It moved through a conventional value chain from materials development, testing, batching, delivery, placement, finishing, and verification.

That distinction is central to concrete decarbonisation. Many lower-carbon materials show promise under controlled conditions but struggle when exposed to construction schedules, contractor warranty requirements, plant processes, weather, site access, finishing tolerances, and client risk appetite. A material that can lower embodied carbon without changing placement methods has a clearer route to adoption than one requiring specialist handling on every project.

The floor slab also sits within a broader materials shift already visible in the UK and Europe. IN Site recently covered FP McCann’s graphene roof tile trials, another example of manufacturers testing whether low-carbon or performance-enhancing materials can move from research into practical construction products.

Concrete remains one of the most difficult materials to decarbonise because cement production is energy-intensive and chemically emissions-heavy. Supplementary cementitious materials, calcined clays, carbon curing, recycled aggregates, alternative binders, and mineralisation technologies are all being developed to reduce that impact. The strongest candidates will be those that can be specified, insured, batched, transported, placed, and warranted within normal construction workflows.

The German slab does not solve the carbon challenge on its own. A 13% reduction is useful, but the wider industry still has to address cement production, transport, structural design efficiency, over-specification, waste, and end-of-life recovery. It does show how value-chain cooperation can accelerate adoption when materials innovators, ready-mix suppliers, and contractors align around a defined application.

Industrial floors are a logical early market. They use large concrete volumes, have defined performance requirements, and are common across logistics, manufacturing, and commercial buildings. If carbon-storing mixes can be repeated reliably in these applications, the pathway to larger slabs, foundations, precast elements, and structural uses becomes easier to test.