Twenty-nine-year-old Kenyan woman invents way to turn plastic waste into bricks ‘stronger than concrete’

Nzambi Matee is the 29-year-old inventor and founder of Gjenge Makers, which manufactures affordable building blocks. In 2020, the United Nations Young Champions of the Earth Program selected Matee as a regional winner.

“Plastic waste is not just a Kenya problem, but it’s a worldwide problem,” Matee told World Architecture. “Here [in] Nairobi we generate about 500 metric tons of plastic waste every single day and only a fraction of that is recycled.”

With a background in material science, Matee quit her job in 2017 as a data analyst and set up a lab in her mother’s backyard. It was here that she started working on the perfect formula of plastic and sand to create her bricks.

“I shut down my social life for a year and put all my savings into this,” Matee told World Architecture. “My friends were worried.” Eventually, Matee invented the machine that converts plastic waste into pavement blocks. Now, Gjenge Makers gets its plastic from packaging factories or purchases it from recyclers.

The company mixes the plastic waste with sand at very high temperatures using an extruder and then compresses it into the pavement block. “Plastic is fibrous in nature, so therefore, the brick ends up having a stronger compression strength,” Matee told World Architecture. “We right now have a capacity of producing 1,000 to 15,000 bricks a day.”

Matee said the company had already recycled 20 metric tons and is aiming to reach 50 metric tons by the end of the next financial year. The affordable bricks cost about $7.70 per square meter.