Through its technical services arm – the Centre for Product Excellence – construction materials leader AfriSam has been showing what is possible when business collaborates with bright young minds at universities.
Partnering with the University of Johannesburg (UJ) in recent years, AfriSam has made its specialists and its laboratory facilities available to UJ for its students – for practical learning as well as to conduct research.
Earlier this year, that partnership led to two research papers being presented at the International Conference on Advances in Sustainable Construction Materials & Civil Engineering Systems, held at the University of Sharjah in the United Arab Emirates. Research for the papers was carried out at the Centre of Product Excellence by UJ Civil Engineering Science student Broadley Miller, and written up by Miller in conjunction with the department’s technical lecturer Johannes Bester and senior lecturer Deon Kruger.
The paper on using a concrete additive to eliminate returned concrete waste volumes – was particularly well received said Bester, who presented on behalf of the authors. The research investigates the effects of a recently developed two-component powdered product in separating returned fresh readymix into fine and coarse aggregates. The product, made from polymers and inorganic compounds, is mechanically mixed into returned concrete to achieve this result.
“This enables reuse of the returned concrete as aggregates for manufacturing new concrete,” says Bester. “The returned concrete waste is therefore eliminated, reducing virgin aggregate usage and reducing the environmental impact of returned concrete.”
The second paper explored the use of recycled aggregates as a replacement for virgin materials to manufacture concrete. They found that fine recycled aggregates have a much greater negative impact than coarse recycled aggregates.
“The presoaking procedure used was problematic when used with fine aggregates, causing a large quantity of excess water to be added to the concrete mix,” says Bester. “This study highlights the importance of planning the process of demolishing a structure to ensure that the best possible quality of recycled concrete aggregate can be extracted.”
