Zeotech is hailing encouraging results from pilot trials on the use of its AusPozz high-reactivity metakaolin product in concrete.

It said phase one trials carried out with building materials firm Holcim Australia demonstrated that AusPozz could be used to decarbonise concrete while improving strength gain and reducing shrinkage compared to controls.

The company delivered 400kg of AusPozz to Holcim last quarter to begin low-carbon concrete pilot trials and 300kg to several other potential customers.

This was produced using kaolin from the company’s Toondoon project, about 200km south-west of Bundaberg.

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The pilot trials evaluated several different mix designs using AusPozz at a 25 per cent binder replacement rate compared to control samples containing standard GP cement and a blend using fly ash.

The results demonstrated an increase in strength gain over 7, 28 and 56 days from samples produced using AusPozz compared to the controls.

AusPozz was also shown to improve concrete performance by reducing shrinkage by 22 per cent at 21 days and 29 per cent at 56 days compared to cement-only binder.

Zeotech said the encouraging results had led to a further sample of AusPozz being delivered to Holcim in February to undertake phase two concrete trials in the lab and field for further commercial validation.

“Our pilot concrete trial results with Holcim are extremely promising, as the goal was to use AusPozz to decarbonise concrete by cement binder substitution without detriment to concrete properties,” Zeotech, chief executive officer James Marsh said.

“However, this test work indicates that AusPozz could offer potential technical advantages in strength and shrinkage improvements that open up more significant opportunities.”