WASTE material from the construction sector can now be used in an innovative green building block used to build low-cost RDP houses through a Department of Science, Technology and Innovation (DSTI)’ Circular Economy Demonstration Fund aimed at demonstrating proven circular economy interventions, such as, technologies, innovative process improvements, social innovations that have not yet achieved scale or impact in South Africa.
This milestone was marked on 11 April 2025 in Hammersdale, KwaZulu-Natal by the Council for Scientific and Industrial Research (CSIR), who partnered with Use-It Beneficiation NPC and Key Bricks, to demonstrate the prototype.
Attendees were guided through the full lifecycle of the building block, from crushing waste glass and rubble to the finished interlocking block and, finally, its use in constructing a housing unit. The green block contains 70% recycled waste content, including crushed waste glass, and construction and demolition waste. The block itself is 100% recyclable.
Designed to interlock like LEGO® blocks, the block requires no cement between layers.
Each block features internal hollows, which when stacked, create channels for installation of electrical and water pipes, reducing the need to cut chasing, ensuring that the blocks remain intact.
Belinda Putterill, MD of Use-it says, “It’s not viable to transport waste glass from KZN to Gauteng for recycling, the margins on this are just too slim, resulting in a lot of this waste remaining uncollected and impacting the environment. We needed to find ways to use glass locally in KZN.” Cities, towns and villages across the country are also plagued with the illegal dumping of building rubble in open spaces.
CSIR project manager Aubrey Muswema says, “Not only is building with this innovative block cost-effective, but it also saves construction time and requires minimal labour and building experience. The top structure was put up by relatively unskilled labour from foundation stage to the roof within seven days – this is only possible because of the interlocking nature of the faceted blocks.
“By using waste as a resource, this interlocking block can unlock new business opportunities in the construction industry. Local businesses and value chains can benefit from the potential to generate additional revenue streams. It also has the potential to accelerate social relief efforts by addressing the country’s housing backlog, while helping to keep our cities, towns and villages clean,” says Muswema.
The block-making machine has been demonstrated to the private sector, municipal officials, housing-sector representatives and other SMMEs in the building sector.
Deputy Director-General at the DSTI, Dr Mmboneni Muofhe, says, “The work that has been done by all partners to date is commendable in demonstrating the principles of ‘reduce, re-use, recycle’, which in turn compels us to rethink the potential of everything that we use on a daily basis. We remain open to the possibility of more partners collaborating with us to demonstrate and scale circular innovations.”
“The aim of the Circular Economy Demonstration Fund,” says CSIR principal researcher and manager of Circular Innovation South Africa (CISA), Professor Linda Godfrey, “is to partner universities and science councils with the private sector, to help business and industry demonstrate, de-risk and scale circular innovations, and in so doing, unlock much needed socio-economic opportunities.”
