Player on a rough field

Once conceived for eternity, building materials such as concrete and asphalt must now keep up with the times. Both products face similar challenges, such as an environmentally friendly, resource-efficient production and significantly lower CO₂ emissions. Pietro Lura, who heads the new "Concrete & Asphalt" lab at Empa, has made this transformation his mission. The research activities of his team – cement chemistry, concrete technology, asphalt and road construction – thus fit perfectly with the objectives of Empa's research focus area, "Sustainable Built Environment". After all, the quality of our built environment is an essential factor for a sustainable society. This includes high-quality and at the same time affordable buildings as living and working space, modern transportation networks and a reliable supply of energy, water and information.

Not an easy task when you consider that concrete and asphalt, with an annual demand of over 4.5 billion tonnes, represent the lion's share of all materials used worldwide. Admittedly, this enormous quantity accounts for a large proportion of global CO₂ emissions. "But that's precisely why optimized material properties directly translate into an enormous reduction in the CO₂ pollution caused by these building materials," explains civil engineer Lura.

Thematically, there are plenty of synergies within concrete and asphalt research because both building materials are confronted with similar challenges. Central topics include the use of alternative ingredients and previously unused secondary raw materials from industrial processes as well as the implementation of efficient recycling processes.

Cement and bitumen, the binding agents on which concrete and asphalt are based, have indeed been used since ancient times. Today, however, research is breaking completely new ground in order to analyze the chemical properties of these highly complex materials, to optimize construction materials or even to equip them with completely new properties. Both fields rely on the latest methods, for example from digitalization (artificial intelligence, machine learning, big data and computer simulations), manufacturing technology (additive manufacturing) and the field of material characterization. "Our goal is to implement the principles of recycling management by developing new composite materials, enabling the cross-recycling of asphalt and concrete, and analyzing alternative binders," says Lura, adding: "An exciting task in a globally ever-growing market.

As the father of three sons, the sustainability of his research is also a matter close to Lura's heart, which at the same time meets the requirements of the United Nations Environment Program (UNEP): New cement-based materials that are more climate-friendly and cheaper are to be developed and used immediately. The cement industry currently accounts for around seven percent of global CO₂ emissions. However, this is likely to increase in future, as demand in Asia and increasingly also in Africa is growing, while production in Europe is stable. When Empa researchers work on the development of new cement- and bitumen-based materials, their aim is to produce less of the harmful climate gas – or even to banish CO₂ from the atmosphere. Currently, around 700 kilograms of CO₂ are released during the production of every ton of cement.

For Lura, driving innovation is a familiar concept, given his experience with inventions from the perspective of a patent examiner from his time at the European Patent Office in Munich. "This is a long-term strategy that will have a strong positive impact on the sustainability of the construction industry," he says. For instance, his team is investigating reduced burning temperatures and modified raw material recipes for building materials. Alternative ingredients such as blast furnace slags or waste products from the electronics industry are being screened for their availability and material properties. And for concrete and asphalt, the recycling process for demolished buildings and road surfaces can still be significantly optimized. To ensure that such approaches do not end up as niche products, new eco-building materials must ultimately meet the same requirements as conventional products, for example in terms of durability and strength.

And in yet another area, Lura sees its activity as a "binder": connecting research with the public. For example, he was editor-in-chief of the renowned technical journal "Materials and Structures" for many years. But Lura goes one step further, because he has always advocated the principle of "open access", i.e. free access to the results of publicly funded research. Researchers should be connected to the world, and the world should have insight into their research. Lura: "It's important to make advances in the scientific community available to the public."

As head of a rather large lab, the researcher certainly misses doing research himself; this is usually his team's task. Nevertheless, Lura stays on the ball when he contributes his ideas and sees them grow into new experiments, technologies or material compositions. It is an exciting time for him to see how globally important decisions for the future of the construction industry are about to be made.