A major focus point for AfriSam’s Centre of Product Excellence is its ongoing product development geared at using downstream materials such as slag, which is well known for its ability to enhance the performance of readymix concrete.
Slag is a by-product from the blast furnace iron manufacturing process, and when used in concrete it can substitute up to 80% of the Portland cement in the mix design. Not only is AfriSam enhancing the sustainability traits of its operation by using this industrial by-product, it is also significantly lowering the CO2 footprint of its cement making activities.
Mike McDonald, manager of AfriSam’s Centre of Product Excellence, points out that while the use of cement is only limited by the imagination, about a ton of CO2 is emitted into the environment for every ton of pure cement that is produced. Only a small percentage of this can be offset by traditional methods such as planting new trees.
“Intervention is, therefore, essential, and some of AfriSam’s milestones with hybrid products include the first commercialisation of a cement with a 42.5 strength class containing less than a 50% clinker component,” he says.
The incorporation of slag is further beneficial in that it improves the durability characteristics of cement, reducing permeability, improving resistance to chemical attack and inhibiting rebar corrosion. All these characteristics improve concrete towards becoming a more sustainable construction material.
Launched in 2010, AfriSam’s Eco Cement offers high workability while allowing a smooth, defect free finish for concrete, masonry and plasterwork. This high performance cement also reduces the heat of hydration in mass concrete.
McDonald says that he expects demand for better performing cements with a low clinker content to grow. This is considering the proposed introduction of a carbon tax in South Africa commencing in 2017, and the “green” building and infrastructure movements that have brought a heightened awareness of the embodied energy and carbon of building materials.
This is exactly why AfriSam has invested so much time and effort into presenting technical courses aimed at helping its customers better understand the product. Attention is also given to the correct use and application of concrete mixes incorporating these hybrid cements.
It is only a matter of time before South Africa sees a greater uptake of the low carbon footprint cements.