MAN-MADE AGGREGATES

A patented process has been developed to produce sand-based granules as a replacement for quarried sand in concrete production offering interesting environmental and technical benefits.

Quarried sand is becoming an increasingly scarce resource, with approximately 40-billion tonnes used by the global concrete industry each year. The environmental impact of excessive quarrying is severe, leading to habitat destruction and the disruption of ecosystems and livelihoods.

This innovative process developed by Munich-based German company, Multicon GmbH, combines fine rock flour, fine and desert sands, mineral binders and specialised additives to create pressure-resistant granules suitable for concrete production. These custom-made pellets, ranging in size from 0 to 16 mm, are optimally graded to improve concrete performance. By using the granules alongside high-speed mixing technology, it is possible to produce high-quality concrete that is up to 25% lighter, hardens faster and in most cases achieves greater strength within 24 hours compared to conventional concrete.

Traditional cement production generates vast amounts of carbon dioxide. The newly developed dual concrete mixing technology has been shown to reduce CO₂ emissions by up to 50%, making the production of high-quality concrete more environmentally friendly and cost-effective. This advancement makes it possible to significantly lower carbon emissions per cubic metre of concrete by optimising cement usage.

It facilitates the production of multi-material cements, enabling the widespread application of high-quality, lower-carbon concrete. In regions experiencing rapid urban development there has been growing interest in these technologies particularly for manufacturing CO₂-reduced concretes and processing desert sands. Long-term agreements have already been established with major cement manufacturers, supporting the transition to more sustainable construction materials. If widely adopted this technology could contribute significantly to reducing the construction industry’s carbon footprint.

This advanced processing technology allows previously unusable sand deposits to be converted into high-performance gravel aggregates with optimised grading curves and mix compositions. These granules can then be used in suspension-based concrete formulations to achieve superior strength and durability.

Processing facilities equipped with high-performance mixers can manufacture both the necessary sand and gravel on-site, reducing reliance on expensive and environmentally harmful aggregate transportation. This localisation of material production is expected to have significant cost and sustainability benefits, particularly in regions where traditional aggregate sources are limited.

Desert sand, historically unsuitable for construction due to its fine, round and smooth particles, can now be transformed into a valuable resource. This breakthrough opens up new possibilities for sustainable concrete production, particularly in regions with abundant desert sand deposits like the Northern Cape and Namibia among others.

The processing of previously unused fine sands is also being explored and show promising results indicating potential for broader application and more useable sand sources.