COVER STORY
Quality aggregate at the heart of construction success
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uality and consistency of aggregate will make or break a project’s success – be it in roadbuilding, readymix, concrete product manufacture or asphalt,” says Amit Dawneerangen, GM: Sales and Product Technical at AfriSam. The construction materials leader highlights the extraordinary lengths that are necessary to ensure that aggregate delivers a long-term return on investment. “This includes standard quality control testing on-site at each of our operations,” says Dawneerangen. “Our laboratory staff conduct tests on product as it is produced and stockpiled. The product is given the green light for dispatch only after being subjected to a grading analysis and flakiness index, as well as calculations to determine the fineness and grading modulus.” The fineness modulus is particularly important for sand used in the manufacture of concrete, as this measures the level of fines and influences the water requirement of the mix. These fines affect both the quality and cost of concrete. The relevance of the grading modulus is mainly in relation to G5-type material for road construction. Specifications for the road material will be detailed in the road design and must be met for the contractor to achieve the required compaction of the road material.
“The categories of aggregate available vary widely, according to their specific applications,” he says. “With our range of rock types at our quarries around the country, we also test these at independent, SANAS-accredited laboratories on an annual basis.”
Bedrock of planning, compliance The foundation for AfriSam’s sustainability, reliability and product quality is rooted in decades of good planning and regulatory compliance, says Glenn Johnson, GM: Construction Materials & Aggregates Operations at AfriSam. “A reliable and consistent aggregate value chain begins many years before any stone is actually delivered,” says Johnson. “Extensive research and planning goes into finding, licensing and establishing a quarry with suitable geology and mineralogy, which is close enough to current and future markets.” These mineral deposits must be registered with the Department of Mineral Resources and Energy, and must remain compliant with a range of demanding regulations. Without the careful selection of the correct type of deposit, he emphasises, it is impossible to produce the quality of material demanded by the various users of construction materials. “With AfriSam’s legacy going back over eight decades, we have plenty of valuable experience in establishing and operating quarries to the
All too often, the quality of aggregate is overlooked in favour of price – a choice that can cost the engineer, contractor and end-user dearly in the long run.
The application of compulsory standards in construction remains a cornerstone of building the country’s infrastructure
highest standards,” he says. “Only in this way can we provide ongoing assurance to customers that we have the right resources for their needs, now and into the future.”
Managing quarry reserves Reserve management is therefore a critical element of AfriSam’s sustainability to ensure that there are adequate reserves of quality products – in close proximity to where they are required by the market. The amount of preparation, discussion and planning that goes on behind the scenes is extensive, he notes. “Cheaper products are often available through producers working a temporary borrow pit or unregulated deposits, but this is where quality can be compromised,” he says. “The danger is that substandard aggregate finds its way into infrastructure and buildings.” This, in turn, affects long-term value for money as structures may not last as long as expected – placing an added financial burden on the end-client or the contractor for unexpected maintenance and repairs. In a worst-case scenario, structures could even
Reserve management is a critical element of AfriSam’s sustainability, to ensure that there are adequate reserves of quality products
