MCi Carbon has used its carbon-mineralised Pozzlock material to replace 5% of the cement in a concrete field trial with Boral in New South Wales, showing a route to lower-clinker concrete for infrastructure.
MCi Carbon has completed a concrete field trial using Pozzlock, a low-carbon cementitious material made at its Myrtle demonstration plant in Newcastle, the Australian carbon technology company said on 23 July. The material replaced 5% of the cement in concrete produced with Boral at its Maldon Cement Works.
MCi Carbon’s process reacts carbon dioxide with mineral-rich feedstocks to form stable carbonates, producing a synthetic pozzolan that can partially replace clinker, the most emissions-intensive part of cement. The company said each tonne of its material can avoid about 0.5 tonnes of CO2 when used in concrete, on top of the carbon dioxide locked in during production.
The trial ran under a SmartCrete Cooperative Research Centre project with Transport for NSW and the University of Technology Sydney. Testing began with mortar and laboratory concrete work at the UTS Tech Lab, which measured workability, slump retention and compressive strength against a fly ash control mix, before moving to commercial-scale batching.
The final stage produced two truckloads back to back at Maldon, one using conventional fly ash and one using MCi’s material. Each yielded about 3.5 cubic metres of concrete that was pumped, placed and finished into a test slab. Fresh concrete properties, including slump retention, air content and density, were comparable, and early-age strength and drying shrinkage sat within the expected range.
The Myrtle plant, opened by Climate Change and Energy Minister Chris Bowen in June, is built to scale the technology from research to industrial output. “Producing Pozzlock at this scale is a critical step in our commercialisation journey,” said MCi Carbon founder and chief executive Marcus Dawe.
The trial used a 5% replacement rate, and the project has set out a path to test up to 10% in later work. For cement makers under pressure to cut clinker, validated supplementary materials that drop into existing batching give a near-term way to lower the carbon content of concrete.
