DialogPunkt Xanten: Gravel and its possible alternatives in house construction

In cooperation with our project, the town of Xanten hosted the first of six events at DialogPunkt Xanten. Christiane Otto-Böhm, member of staff of the Building and Planning Department in the Wesel district administration, spoke about the ‘Gravel turnaround for our homes’ and hit the mark. Florian Gaisrucker, our Innovation Manager Society, made the initial connection: ‘Sustainability is not just synonymous with “green”. One of the topics we address in our ‘DialogPunkte’ is the sustainable design of our cities. This also includes the conscious use of resources and building materials.’

Grappling with a finite resource

Christiane Otto-Böhm summed it up right at the beginning of her presentation: ‘The controversy over gravel’. With 80 per cent, gravel and sand are the most important components of concrete, which has established itself in the construction industry as a flexible and easy-to-produce building material. However, the gravel and sand deposits in Germany are not evenly distributed. Formed during the Ice Age, there are huge deposits in the Lower Rhine region, among others. Of the 275 million tonnes of gravel mined in Germany each year, approximately 13 million tonnes or 6 million cubic metres are extracted in the district of Wesel. Gravel and sand have been mined in the district of Wesel for over 120 years. During this time, some 5,100 hectares of land have been excavated. Around half of this area has been backfilled or stockpiled. 90 lakes were left behind. According to Christiane Otto-Böhm, more than 45 per cent of these standing bodies of water are not being put to any visible use. This leads to resentment among some sections of the population.

Unlike alternative building materials from the plant world, for example, gravel is a finite raw material and does not grow back. In short: ‘’Once it’s gone, it’s gone‘’. This is also recognised by the district of Wesel, which is committed to the sustainable use of the local raw materials gravel and sand. The public sector accounts for the greatest demand in the construction industry, which is where the district of Wesel comes in with its ‘Gravel Turnaround’ project. ‘We are aware that we cannot do without gravel as an important building material. There is also no single alternative to replace gravel,’ Christiane Otto-Böhm argued in favour of a differentiated approach to the topic and presented various options for reducing gravel consumption. She went into detail about processing options as well as the advantages and disadvantages.

Her proposed solutions:

• Replace gravel with recycled concrete in concrete production – with the same final quality
• Save concrete in house construction by using fibre-reinforced concrete, filigree and hollow core slabs, 3D printing or prefabricated concrete parts, for example
• Use alternative building materials such as wood, clay and hemp. These three materials are centuries-old and tried-and-tested materials that are once again emerging from their niche existence.

She urged all future house builders and amateur DIY enthusiasts to consciously consider building materials, determine the pros and cons for themselves individually and plan ahead.

‘Questions were possible at any time during the presentation and there was also a lively discussion afterwards,’ says Florian Gaisrucker, looking back on the event with satisfaction. Pauline Becker from TIX – Touristen Information Xanten was also pleased with the good reception of the first DialogPunkt Xanten event and is looking forward to the upcoming evenings. On 4 March, Akke Wilmes, energy consultant at the NRW consumer advice centre in the district of Wesel, will be a guest for a workshop on the subject of ‘Electricity from my balcony’.