South African aggregate producers are drawing up plans to formalise the aggregate recycling industry to ensure that previously used materials are given new life.
The Aggregate and Sand Producers Association of Southern Africa (Aspasa) held a workshop on aggregate recycling at which Aspasa director Nico Pienaar said aggregate recycling will become an important means of reducing the environmental impact of quarrying and construction.
He added that, as resources become scarcer in built-up areas, the use of recycled aggregates could offset rising transport costs of transporting virgin aggregates into the cities.
Pienaar explained that aggregates are the most mined minerals in the world, driven by building professionals’ requirements for concrete mixes, road surfaces, railway ballast or decorative purposes.”
Virgin aggregates are of the purest quality and have known characteristics. However, when recycled, the aggregates used in building materials are altered with the addition of concrete, fines and chemicals.
“Therefore, for it to become a viable product, we need to establish and implement quality control procedure wherein we can establish that the recycled material can be used in exactly the same way as a non-waste, that it can be stored and used with no worse environmental impacts than the material it is intended to replace, and that it conforms to the same specification as aggregate products,” Pienaar explained.
A working committee has already been formed in the Western Cape, and best practice are being compiled for the inclusion of secondary materials in road layers and how and when to substitute virgin materials. Concrete specifications are also being examined to include the use of recycled materials and the effect on durability.
Pienaar noted that guidelines are also being put in place to assist recyclers in working within the parameters of legislation and best practices as dictated by various professional bodies within the construction industry.
Pienaar concluded that recycled aggregates will play an important role in offsetting the rising price of virgin aggregates and companies and municipalities should think twice about relegating all building waste to landfill sites.
