‘Green’ concrete nets maker $3.5m grant
A $3.5 million grant from a government environmental fund is set to firm up a Hamilton company’s quest for a better concrete that can help cut construction sector carbon emissions.
Every tonne of cement takes about 900kg of CO2 to produce but Dr Bram Smith, through his Hamilton-based company Kayasand, claims he can reduce the emissions by 60kg for every cubic metre of concrete that cement is used in.
This is by diminishing the use of the cement in concrete. The trick, he says, is manufactured sand. Get it right, and the savings in cement costs could be huge.
Kayasand, a distributor of sand manufacturing technology, is working to produce more sustainable concrete and has set up its first plant in Waikato.
It has also pulled in $3.5m from New Zealand Green Investment Finance (NZGIF), a Crown-owned green investment bank established to lower greenhouse gas emissions, and a further $1.8m from private investors.
The company’s technology removes water and sand mining from the concrete equation – both resources that inflict a major toll on the environment.
Smith, who is Kayasand’s general manager, says their technology can reduce or in some cases eliminate the need for natural sand dredging.
It uses by-products and recycled materials such as quarry crusher dust and recycled glass to manufacture sand of such quality that it makes stronger concrete than natural sand when mixed with cement, he says.
The company’s goal is to reduce carbon emissions from concrete production by up to 20% using this method.
The technology is based on a New Zealand invention that was developed in Japan and used in over 300 plants across Japan,
China, India, and Australia.
Smith said their process is dry, as opposed to the current method, which uses water to process crusher dust.
‘‘There’s a lot of demand for aggregates, for example around Auckland at the moment, and a bit of an aggregate shortage.’’
And there was no shortage of rock in the ground and the quarries were going after it.
‘‘You’ve got to get aggregates from somewhere for buildings, roads and that sort of stuff.
‘‘Concrete gets potentially a bit of a bad rap because of the environmental impact, but a building that’s built with concrete lasts for 100 years ... it’s waterproof, it’s fireproof.
‘‘There are lots of upsides to concrete and we just need to mitigate the harm that it does.’’
As demand for concrete – the most popular building material in the world – grew, the impact of harvesting the material grew alongside it.
Smith said people were becoming more aware and concerned at the same time.
‘‘The majority of emissions from concrete production come from making the cement to bind the concrete together.’’
The challenges for companies like Kayasand are around consenting issues and investment.
Kayasand’s first high-tech manufacturing demonstration plant in Waikato is expected to open next month and it plans to be operating 40 plants in New Zealand and Australia by 2030.