19.09.2019

No sand, no concrete

Interview with Ulrich Nolting and Martin Möllmann

Most people assume sand is one of the most plentiful resources on Earth. Yet supplies are actually limited. Nevertheless these tiny grains of quartz are the most commonly used natural resource, after water. Sand is also behind the worldwide boom in the building industry. For without sand, you have no concrete. We talked to Ulrich Nolting and Martin Möllmann about the consumption and procurement of sand and possible alternatives.

The United Nations’ environment program is sounding the alarm. Worldwide supplies of sand are dwindling. What is the industry in Germany saying?
Nolting: Sand is the term used for a sediment with a grain size of between 0.063 and 2 mm. Basically sand can consist of all kinds of materials. We distinguish here between building sands and industrial sands such as quartz sand. Building sand, unlike quartz sand, is available right across Germany, with only a few regional exceptions. Unfortunately there are all sorts of restrictions and requirements. The problem is not availability, but the general framework. The onus is on the politicians to change this.

How much sand do you need to produce one cubic meter of concrete?
Möllmann: Beton besteht aus groben und feinen Gesteinskörnungen, Zement und Wasser. Gewichtsmäßig haben die groben Gesteinskörnungen wie zum Beispiel Kies oder Splitt den größten Anteil. Gleich danach kommen die feinen Gesteinskörnungen, das ist der Sand. Um einen Kubikmeter Beton zu produzieren, benötigt man rund 700 kg Sand (trocken, ohne Eigenfeuchte).

Where does Dyckerhoff get its sand from?
Möllmann: Dyckerhoff betreibt in Deutschland und den Benelux-Ländern Transportbetonwerke, davon allein in Deutschland rund 110 Anlagen. Wo immer es möglich ist, verwenden wir lokale Sande. In unseren Kernmärkten, wie zum Beispiel der Rhein-Main-Region, verfügen wir über eigene Rohstoffvorkommen. Parallel arbeiten wir mit unserem Wilhelm-Dyckerhoff-Institut daran, Abbruch- und Recyclingmaterial so aufzubereiten, dass es in unseren Betonrezepturen eingesetzt werden kann. Die Lieferung der Sande ins Transportbetonwerk erfolgt meist über die Straße. Für unsere Werke im Rhein-Main-Gebiet und im Emsland spielt aber auch das Binnenschiff als Transportmittel eine wichtige Rolle.

Are there particular environmental standards that apply to you regarding the procurement of sand?
Möllmann: Beim Abbau von Sand ist die Bindung durch die Gesetzeslage in den jeweiligen Bundesländern sehr eng. Hier spielen vor allem lokale Naturschutz- und Wassergesetze eine Rolle. Jeder Sandabbau richtet sich nach den Genehmigungen vor Ort. Der Bedarf scheint enorm. Allein für die Hamburger Elbphilharmonie sind angeblich 63.000 Kubikmeter Beton verbaut worden …
Nolting: … und mit diesem Beton ist ein Wahrzeichen entstanden, das Hamburg mittlerweile prägt. Eine Ikone der Architektur. Der sinnvolle Einsatz von Ressourcen ist immer dann nachhaltig, wenn diese langfristig genutzt und anschließend recycelt, also wieder­verwendet werden können. Bei einer Lebensdauer von Gebäuden von 80 Jahren und mehr ist das so. Insofern sind die rund 44.000 Tonnen Sand bei der Elbphilharmonie erstklassig eingesetzt.

Demand for concrete seems insatiable. For the new philharmonic concert hall, the Elbphilharmonie, in Hamburg, it is reported that 63,000 cubic meters of concrete were needed …
Nolting: … and with this concrete a real landmark has been created that is shaping the image of Hamburg. It is an icon of contemporary architecture. Sensible use of resources is sustainable when these resources are used long term and then recycled, in other words they can be used again. With a lifetime of 80 years for buildings, this is more than met. In those terms, firstclass use was made of the 44,000 tonnes or so of sand that went into the Elbphilharmonie.

How much sand does Dyckerhoff need each year?
Möllmann: In 2018 Dyckerhoff produced around 4.5 million cubic meters of concrete in Germany, Luxembourg and the Netherlands. For that, around 3.2 million tonnes of sand were needed.

Sand is not just sand. Sand that is too fine—desert sand, for example—is clearly not usable in the production of concrete …
Nolting: That is correct. It is estimated that up to 95 percent of the sand available worldwide cannot be considered for industrial purposes. Desert sand, for example, is not suitable for processing into concrete because the grains have been worn down too smoothly by wind and weather. Current research, however, is looking at this theme and we are not excluding the possibility that in this area, too, innovative solutions and applications will emerge.

Have you had any problems in procurement?
Möllmann: The only problems we had and still have are in logistics. In the dry summer of 2018 many rivers had low levels of water for months. On the Rhine and on other waterways there were times when shipping was halted entirely, or only permitted with reduced load. And, because we supply sand to some of our readymix concrete plants by water, at times production at some of our facilities was only possible in restricted quantities, or at much higher cost. Some of the logistics operations had to be moved to the roads temporarily. Which brings me to an everpresent problem in procurement: The haulage companies have great difficulties in finding suitable truck drivers. So, in transport operations, bottlenecks are happening more and more, and that can have an impact on supplies of sand.

Recycling building rubble—is that an alternative to extracting natural sand?
Nolting: Today the mineral component in building waste is almost all recycled, so it is reused and flows back into the resource cycle. Recycled aggregate is increasingly being used, including in concrete. Thanks to the standards introduced in 2017 (DIN 4226101 and 102) we no longer have to go through the complicated process of applying for general building supervisory approval or obtaining casebycase approval on environmental compatibility. But we must be realistic here. In future we will only be able to master the building challenges of the future by using recycled material.

Is research being conducted into types of concrete that do not need sand?
Nolting: We are doing research in all directions on concrete for the future. And of course looking very closely at how to optimize the quantity of sand.

 

Ulrich Nolting has been Managing Director of the InformationsZentrum Beton GmbH since 2015. A specialist in reinforced concrete, Ulrich Nolting also has qualifications in advertising technology and the advertising industry (Dipl.-Wirt.-Ing.) and in international marketing (Dipl.-Exp.-Wirt). Following positions in advertising agencies and printing businesses, he was assistant to the Managing Director of Südwest Zement GmbH from 1995 to 1999, where from 2000 to 2001 he was also an authorized signatory. In 2002 he became Managing Director of Beton Marketing Süd GmbH.

 

Martin Möllmann has held various positions at Dyckerhoff since 1991. Today he is a Director, responsible for the areas of product marketing and sales of special cements—above all Dyckerhoff Weiss and CSA cements—in the business area Germany / Western Europe. A graduate in construction engineering and business, Möllmann is also engaged on a voluntary basis in professional training in the concrete industry and is a board member of the Informationsgemeinschaft Betonwerkstein e.V.

 

title picture ©Hauke Hass