Idea fromEurope nowaKiwi reality
but also the roof. ‘‘This is another reason why the potential cost savings in house building are so huge as it simplifies the whole building process.’’
Aside from making good use of a waste material which cannot otherwise be recycled, he says EPS does not contain any chlorofluorocarbons and hydro fluorocarbons so does not harm the ozone layer. The environmental benefits don’t stop there either.
‘‘It also has no nutritive value. It won’t trigger fungus or any other bacteria growth and has no dangerous effect on plants or animals.’’
Axis has already had plenty of interest in his lightweight concrete from some major players in the building sector, construction industry and housing companies.
‘‘From every angle you look at it, with this product everyone is winning. It makes construction of buildings faster, more efficient as well as clean and green, ’’ says Axis.
Sustainable building: When Dimitris Axis emigrated to New Zealand from his native Greece 26 years ago, he did not imagine he would end up developing his own type of concrete.
‘‘My first love was natural stones. I supplied marble and granite to the building industry.’’
However, after a trip back to Europe in 2008, he began thinking about the possibilities of better and more economic ways of building houses.
‘‘When I returned to Europe I noticed how extensively lightweight concrete was used in the construction industry and realised it was the way of the future.’’
Once back in New Zealand in 2009, he studied for his Quantity Surveyor National Diploma and at the same time he began to ponder how to introduce lightweight concrete to New Zealand. The biggest challenge he faced was finding a substitute for pumice stone used extensively to make lightweight concrete in Europe but which isn’t widely available in New Zealand.
This was when he hit upon the idea of using old polystyrene instead. He began experimenting, largely by hand, using buckets to mix cement and polystyrene granules known as EPS. These are bonded using a combination of water and a range of additives. These ‘‘glue’’ the cement and polystyrene beads together. The product has been subject to numerous independent laboratory tests to assess its strength and durability which Axis says have yielded excellent results.
With the support of PHP Contractors and a range of other people and companies, Axis has been able to set up a commercial production facility in Middleton which incorporates several unique pieces of plant and equipment built specifically to make the lightweight concrete.
The production process starts with recycling the old polystyrene, delivered to the factory by Waste Management which has a supply contract with Axis. The polystyrene is broken down into the bead-like EPS components by being fed into a machine with rotating knives. The EPS is then stored in a silo and repackaged from there into half cubic metre bags. The concrete is made up in batches by mixing the polystyrene with cement, water and the adhesive additives in a large trough fitted with a rotating augur like a giant cake mixer.
Once mixed, the concrete destined to be made into panels is poured into amould and left to dry out. The completed blocks are 2400mm by 600mm by 600mm. The blocks are cut using a specialised cutting machine with adjustable horizontal and vertical cutting blades. This allows a wide range of thicknesses and shapes to be cut from a block depending on the end use. Concrete destined for filling in situ formwork wall modules will be mixed on site and pumped directly into the form work.