Cleaning up plastic waste by turning it into building materials

If 27-year-old Nzambi Matee was to take something you don’t need in your house, she would go for your plastics. Not to dispose of them, but because she has a noble idea on making good use of them.

Ms Matee, a Bachelor of science in Physics graduate from JKUAT, and a material scientist, is the founder of G-Jenge Makers Ltd.
The aim of the Nairobi-based social enterprise, she explains, is to address the prevailing issues of plastic waste pollution.

She does this by recycling and upcycling waste plastic into strong and beautiful construction products such as paving bricks, paving tiles, hatch and manhole covers.

“We use polymers from plastics and rubber to make building products,” she says.

Through partnerships with skilled and unskilled youth and women’s groups, Ms Matee and her two co-founders are able to collect plastic waste from the community around Industrial Area and South B neighbourhoods.

Strength of materials
The co-founders are Ms Paula Aschenbrenner, an environmental physicist based in Germany and Ms Margret Matee, the board adviser.

The latter happens to be Nzambi’s mother, of whom the daughter says: “She brings on board 20 years of experience in business management”, to explain why she was brought on board.

After collection, the plastic waste is sorted, cleaned and then crashed before being put into an extruder machine where the polymers are heated and combined with sand and a hardener in a process referred to as extrusion.

At the moment, G-Jenge Makers is producing paving blocks to prove the concept and strength of the materials. They are also producing bricks for affordable house construction.

Brick colour and shape

She says: “After casting the columns, construction work becomes easy. Since bricks are already pre-moulded and pre-cast, it is only a matter of stacking them together using steel beams to reinforce them. This eliminates the need for mortar and makes the process less laborious.”

According Ms Matee, pre-casting allows the client to customise their houses to taste in terms of brick colour and shape, and even match the pavers.

Also, the resulting house is sturdy, less costly and consumes little time during construction, since no time is lost in mixing mortar and placing it between bricks. There is also no time needed for curing.

All these efforts lead to a reduction in time and construction cost. “If all goes according to plan, we expect to build a two-bedroom house in one month, at a cost of Sh800,000,” Ms Matee says.

Kenyans are not known to embrace alternative methods of construction, afraid that they could be inferior to conventional methods that they are familiar with. This explains why Portland concrete (cement-based concrete) has dominated at the expense of polymer concrete (a type of concrete that uses polymers to replace lime-type cements as a binder), despite the latter penetrating other countries.

Ms Matee is banking on the renewed commitment to affordable housing to push the idea through the market.

“The concept and science behind making buildings and reinforcing them with polymer is as old as time. A good example is the Colosseum, an oval amphitheatre in the heart of Rome, Italy. It is the largest amphitheatre ever built and now a heritage building,” says Ms Matee says.

Its builders used cement concrete and reinforced that with polymer, she adds.

Most people favour Portland cement concrete because of its arguably adhesive nature and the strength when it comes to binding the sand and the ballast, but Ms Matee says polymer concrete is even stronger and less brittle.

“If you were to hit a building constructed using Portland concrete with a wrecking ball, it would shutter almost immediately. However, a house built with polymer-based concrete will behave like a plastic, bending for a long time before shuttering,” she says.

“I consider myself a futurist”, Ms Matee says, and adds:

“It is estimated that by 2050, the world’s population will be somewhere around 8.6 billion people, with about 1.3 billion of these living in Africa. Already, decent affordable housing is a problem and when you look at it, apart from land, the cost of materials is the other factor that pushed construction costs up, yet we have so many resources like plastics that we have not exploited.”

By converting plastic waste into useful products, she points out, Ms Matee has found her purpose in life. She told DN2 that she resigned from a prime job with a major petroleum company to chase her dreams, much to the disapproval of family and friends.

Cleaning the environment

She has since received training on how to make building materials from plastics at Wastson Institute in USA and the Germany-based European Organization for Nuclear Research, also known as CERN.

“This is my little way of killing two birds with one stone. Other than cleaning the environment, we will be providing shelter, which is a human need,” she says.

Ms Matee revealed that she is working closely with chamas (groups) keen on providing affordable housing. This is a market-penetration strategy, which is already bearing fruit. She told DN2 that she has 34 orders to run this year.

At ShelterTech Accelerator, a Habitat For Humanity’s start-ups acceleration programme happening at Strathmore University-based iBiz Africa, Ms Matee, alongside other young people, is gunning for the top prize: a Sh5,000,000 worth of investment into her business and a chance to pitch to investors.

Besides the co-partners, she has a staff of three, who are brought on board on a need basis.

Ms Matee believes that if young people, like her, were to be accorded the necessary support from the government and private entities during their baby steps, they would not only create employment for other young people, but they would also help the country find local solutions to local problems.