In a significant step for the company, laboratory test work has confirmed Green360 Technology’s new high-reactivity metakaolin is well suited to producing low-carbon cement and high-performance structural concrete.
The company produced metakaolin samples from its kaolin resources and deposits that exceed the quality benchmarks of other metakaolin products currently available in Australia.
Metakaolin is a sought-after component of low-carbon cements. The anhydrous aluminosilicate is produced via the thermal decomposition of kaolin, a naturally occurring clay containing kaolinite and traces of quartz and other minerals.
The kaolin is baked in a kiln at high temperatures for about 90 minutes. This causes a chemical change, transforming the material into metakaolin, which can react with water and calcium hydroxide to form cement.
By successfully producing the reactive metakaolin, Green360 has completed the first leg of the new product’s development pathway.
The company ran lab tests on its new product in partnership with Murdoch University in Perth, using infrared spectroscopy and X-ray diffraction analysis.
The analysis confirmed the complete mineral transformation of kaolin into an amorphous compound suitable for use in high-performance concrete.
Amorphous minerals lack an organised, repeating internal crystalline structure, potentially making them stronger than their crystalline counterparts.
This enhanced strength particularly applies to finely ground metakaolin products used with coarse cement components, such as sand and gravel.
Green360 Technologies executive chairman Aaron Banks said: “The successful production of metakaolin from our resources and deposits is a significant milestone for the company. This achievement allows us to rapidly pursue testing and optimisation of low-carbon cement formulations utilising our own metakaolin and industrial byproducts to ultimately deliver low-cost, low-carbon alternatives to traditional Portland cement.”
Murdoch’s testwork has shown that Green360’s metakaolin has a very high amorphous content, greater than 88 per cent and a correspondingly very low residual crystalline content, placing the company’s product among the highest quality available.
The company says other Australian metakaolin products typically range from 55 per cent to 75 per cent amorphous content, depending on their source material, quality and processing conditions.
In general, the addition of metakaolin contributes to a denser microstructure in concrete, which increases the durability and longevity of structures in which it is used.
This attribute makes the material suitable to partially replace traditional ordinary Portland cement (OPC) and for use in premium structural concretes for specific high-strength applications.
Importantly, metakaolin production emits far less carbon dioxide than OPC manufacturing.
Also, in a beneficial double whammy, metakaolin replaces some of the OPC that would otherwise be used in concrete, eliminating some of its vast carbon dioxide emissions.
Other additives such as fly-ash and furnace slag are often added to cements, but they are typically coarser and have varying consistencies, strengths and reactivities.
Green360 is progressing to the next development stage of its new high-quality metakaolin, kicking off real-world commercial-scale concrete trials with its joint-venture partner PERMAcast.
The company is designing its metakaolin/cement formulations in cooperation with both Murdoch University and PERMAcast to meet Australian standards.
The company has already begun its trial batches using the new formulations, which will be subject to key short and long-term performance tests, including workability, ease of finishing, slump retention, temperature sensitivity and setting times.
The test regimen will also examine the new cement/concrete compatibility with other additives such as plasticisers, to ensure it will perform to real-world precast standards.
Green360 will also run parallel test comparisons with other typical standard industry concrete formulations, including OPC with slag and fly-ash cement fillers.
These trials are a key step in validating the performance of the company’s metakaolin-based low-carbon cement formulations in commercial concrete products.
Green360 is making significant strides towards the development and commercialisation of high-quality, low-cost, low-carbon cement formulations, which will address growing pressure for the cement and concrete industry to cut its high carbon footprint.
With its breakthrough high-quality metakaolin, the company looks like it is well on the way to playing its part in the green initiative.
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By Doug Bright
