Construction World August 2021

AfriSam’s National Operations Manager for readymix. “Ideally, a readymix company should have strict internal processes that are linked to quality accreditations such as ISO:9001,” says Wearne. “Frequent calibration needs to be done internally – at AfriSam this happens every two weeks – while an external calibration is done twice a year.” He notes that the modern technology in AfriSam’s batching plants allows the direct downloading of the concrete technologists’ mix designs, which are automatically implemented without human intervention or error. The system also flags any deviation from the pre-set volumes and parameters directly to management. Tough conditions The difficult economic climate has certainly not made the buying choices of contractors any easier. As the construction sector has shrunk, so competition has risen leading contractors to trim costs across the board. This has been a key factor affecting the readymix market, where some suppliers have cut quality corners in an effort to sell their product as cheaply as possible, says Dawneerangen. “For contractors who are under pressure, it is clearly very tempting to procure at the lowest cost,” he says. “But there is a careful balance to be struck here, as a compromise on readymix quality carries serious risk – not just for a project but for the sustainability of a contractor’s business.” To avoid the vicious cycle of narrow construction margins impacting on the readymix business, companies like AfriSam have squared up to the challenge of controlling their own costs in response to customer needs – while still maintaining the highest standards. Enabling progress It is also worth remembering that the integrity of South Africa’s concrete infrastructure and buildings has benefitted hugely from the growth of readymix as a delivery channel for bulk concrete. While much of Africa still relies on site-batching for construction work, the local industry has increasingly used readymix – recognising the value in its consistency and performance. “The guaranteed quality and service that come with readymix have allowed contractors to leave the concrete side of the business to us, where we have become the experts in this field,” he says. “This has also opened the door to the rapid development of complex mixes, complete with admixtures and other innovations.” He emphasises that concrete technology has evolved considerably, becoming a science in its own right. Contractors and designers have therefore been able to specify highly specialised concrete mixes, especially for large projects – relying heavily on the technical expertise and experience of established, well-resourced readymix providers.

“With fewer of these mega-projects now on the table, it is generally the ‘run of the mill’ concretes such as the standard 30 MPa mixes, that are predominantly in demand which many providers can reliably deliver,” says Dawneerangen. “However, even here there is no room for complacency, as strict standards should always apply, and this requires

the right equipment and procedures.” Not just a commodity

He highlights that the end-quality of concrete is largely influenced by the input materials – including cement, aggregate, sand, water and admixtures – all of which have their own relevant SANS requirements. Cement, for instance, must comply with SANS 50197 while standards for aggregate and sand are defined in SANS 1083. “It is vital that the consistency of each ingredient is ensured throughout a project, as this is the basis of the consistency of the concrete itself,” he says. “At our AfriSam product technical laboratories, we test the quality and consistency of input materials, and use these results to assist in the monitoring in concrete performance on site.” For contractors, reliable and on-time delivery of readymix is paramount in keeping projects progressing smoothly, so suppliers must be able to demonstrate the capacity and flexibility of their truck fleets and scheduling systems. “A customer’s trust in the quality of a readymix product must extend from its input material, through its manufacturing, its efficient placement and finally its performance,” he concludes. “A weakness at any stage presents potentially unmanageable risk for them.” 

Concrete technology has evolved considerably, becoming a science in its own right.

Left: The end-quality of concrete is largely influenced by the input materials including cement, aggregate, sand, water and admixtures. Right: AfriSam is regularly brought in – at a relatively late stage – to salvage projects which have run into difficulty because another readymix provider has not been able to meet the standards required.

21 CONSTRUCTION WORLD AUGUST 2021