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Building on sand: the problem of resources in the construction industry

“Everyone in the construction industry is fully aware that using vast quantities of sand is a problem. It simply cannot go on like this.” Prof. Agathe Robisson, Director of the Building Materials and Materials Technology research unit at TU Wien, has a very succinct description for the current situation. Sand is the resource with the second highest consumption worldwide, trailing just water. But it is produced at a far slower rate than it is needed, and some of the expanding extraction sites are having drastic effects on the surrounding area, from groundwater salinisation and threats to biodiversity through land consumption to the burgeoning risk of storm surges when sand is extracted near the coast. Do alternatives even exist?

Sand is not always the same

The wording ‘scarcity of sand’ sounds peculiar initially if we consider the endless beaches and the numerous and sizeable deserts. However, the problem is that desert sand – which accounts for 95% of the world’s deposits – is too fine and smooth to enable the necessary cohesion for the production of concrete. UN figures indicate that the remaining 5% amount to 40 to 50 billion tonnes per year, two thirds of which end up in concrete mixers. But the problem at hand is not just the scarcity. The ongoing and unabated extraction of sand as a resource as described in the beginning is equally concerning. Extending the lifecycle of concrete would offer a potential solution: ‘Urban Mining’ (LINK to the glossary) is a term used to describe the circular economy in the construction industry.

Recycling possible, rethink necessary

“We need a circular economy and must use our building stock to achieve this goal!, says the material researcher Agathe Robisson. “Widespread recycling of building materials and mineral raw materials will become more important in Austria as well”, adds Christian Heiss from the Chair of Mining Engineering and Mineral Economics at Montanuniversität Leoben. Just taking a look at Germany emphasises the potential: According to the German Environment Agency, “the German economy uses around 1.3 billion tonnes of materials on the domestic market each year. Of these resources, metals and construction minerals in particular often remain in the infrastructures, buildings and everyday items for a long time. This means that immense stocks of materials have accumulated over decades and now present significant opportunities as sources of secondary raw materials. Although these secondary raw materials cannot always be reused for their original purpose, planning their deployment in good time would contribute significantly to satisfying primary demand. “Often they do not even need to have maintained their original quality, for instance in road or path construction”, says mining expert Christian Heiss. But urban mining – so the processing and recycling of materials from buildings and roads – still presents society and the construction industry with a challenge. The focus in this regard is on raw materials that tend to be used less frequently, which simplifies the recycling process. Christian Heiss: “People used to use 10 raw materials to build a house. But today, even a window contains a larger number than would have been needed for the whole house a century ago.”

Less is more – Can alternative construction materials step up?

Fewer types of material, less ‘fresh’ sand – might another approach even include less cement and concrete? The use of concrete in the history of construction dates back to Roman antiquity, and buildings in Turkey already contained mixtures of mortar around 10,000 years ago. But concrete did not experience its golden age until the 20th century. A change in mindset and a shift in focus to other, more sustainable construction materials would still be worthwhile. The 18th International Architecture Exhibition in Venice adopted the slogan ‘The Laboratory of the Future’ and addressed the issues of declining resources, climate change and more sustainability: There are auspicious projects that draw on wood, clay and bamboo. Besides that, there have been successful experiments with mycelium, the branched root of fungi, which have led in some cases to practical applications.

So there are alternatives. Our challenge as project developers is to adopt revolutionary and sustainable practices to meet current needs. It is an exiting and complex undertaking that we are only too pleased to accept. Current projects illustrate how we are proceeding

Read more (optional):

  1. 18th International Architecture Exhibition in Venice ‘Building the future’

Sand is becoming scarce – raw materials in the construction industry

Waste management and urban mining

Trend terms in the construction industry