The Concrete Yearbook is a very important source of information for engineers involved in the planning, design, analysis and construction of concrete structures. It is published on a yearly basis and offers chapters devoted to various, highly topical subjects. Every chapter provides extensive, up-to-date information written by renowned experts in the areas concerned. The subjects change every year and may return in later years for an updated treatment. This publication strategy guarantees that not only is the latest knowledge presented, but that the choice of topics itself meets readers' demands for up-to-date news.

For decades, the themes chosen have been treated in such a way that, on the one hand, the reader gets background information and, on the other, becomes familiar with the practical experience, methods and rules needed to put this knowledge into practice. For practising engineers, this is an optimum combination. In order to find adequate solutions for the wide scope of everyday or special problems, engineering practice requires knowledge of the rules and recommendations as well as an understanding of the theories or assumptions behind them.

During the history of the Concrete Yearbook, an interesting development has taken place. In the early editions, themes of interest were chosen on an ad hoc basis. Meanwhile, however, the building industry has gone through a remarkable evolution. Whereas in the past attention focused predominantly on matters concerning structural safety and serviceability, nowadays there is an increasing awareness of our responsibility with regard to society in a broader sense. This is reflected, for example, in the wish to avoid problems related to the limited durability of structures. Expensive repairs to structures have been, and unfortunately still are, necessary because in the past our awareness of the deterioration processes affecting concrete and reinforcing steel was inadequate. Therefore, structural design should now focus on building structures with sufficient reliability and serviceability for a specified period of time, without substantial maintenance costs. Moreover, we are confronted by a legacy of older structures that must be assessed with regard to their suitability to carry safely the increased loads often applied to them today. In this respect, several aspects of structural engineering have to be considered in an interrelated way, such as risk, functionality, serviceability, deterioration processes, strengthening techniques, monitoring, dismantlement, adaptability and recycling of structures and structural materials plus the introduction of modern high-performance materials. The significance of sustainability has also been recognized. This must be added to the awareness that design should focus not just on individual structures and their service lives, but on their function in a wider context as well, i.e. harmony with their environment, acceptance by society, responsible use of resources, low energy consumption and economy. Construction processes must also become cleaner, cause less environmental impact and pollution.

The editors of the Concrete Yearbook have clearly recognized these and other trends and now offer a selection of coherent subjects that reside under the common ‘umbrella’ of a broader societal development of great relevance. In order to be able to cope with the corresponding challenges, the reader can find information on progress in technology, theoretical methods, new research findings, new ideas on design and construction, developments in production and assessment and conservation strategies. The current selection of topics and the way they are treated makes the Concrete Yearbook a splendid opportunity for engineers to find out about and stay abreast of developments in engineering knowledge, practical experience and concepts in the field of the design of concrete structures on an international level.

Prof. Dr. Ir. Dr.-Ing. h. c. Joost Walraven, TU Delft

Honorary president of the international concrete federation fib

Univ.-Prof. Dr.-Ing. Stephan Freudenstein has been a full professor at the Chair and Institute of Road, Railway and Airfield Construction at the Technical University of Munich and director of the test institute of the same name in Pasing, Munich, since 2008. After graduating in civil engineering at TU Munich in 1995 and working at Heilit + Woerner Bau AG, Stephan Freudenstein became a research associate at TU Munich's Chair and Institute of Road, Railway and Airfield Construction in 1997. In 2002 he joined Pfleiderer Infrastrukturtechnik GmbH, now known as RAILONE GmbH, in Neumarkt in der Oberpfalz, Germany. While there, he headed up the technology and development department. He was responsible for prestressed concrete sleepers and the technical side of various ballastless track projects in Germany and farther afield. The main focus of Prof. Freudenstein's research is the structural design of road and rail superstructure systems and aviation surfaces. He is a member of numerous German and European technical standard committees and committees of independent experts.

Dr.-Ing. Konstantin Geisler graduated in civil engineering at TU Munich in 2010. He was awarded his doctorate by that university in 2016 and now works in academic research at TU Munich's Chair and Institute of Road, Railway and Airfield Construction.

Dipl.-Ing. Tristan Mölter studied civil engineering at TU Munich. Since 2000 he has been responsible for noise control, bridge equipment and provisional bridges at the technology and plant management department of DB Netz AG in Munich. He is the chair of the structural engineering commission (FA KIB) at VDEI (association of German railway engineers) and a member of numerous German and European technical standard committees and committees of independent experts.

Dipl.-Ing. Michael Mißler studied civil engineering at TU Darmstadt. Since 1999 he has been responsible for ballastless track engineering in the track technology management department of DB Netz AG in Frankfurt/Main, Germany. Further more he is one of the responsible persons for the subjects of track elasticity and track stability at DB. He is a member of numerous German and European technical standard committees and committees of independent experts.

Dipl.-Ing. Christian Stolz studied civil engineering at Cologne's University of Applied Sciences. Since 2010 he has been responsible for ballastless track engineering in the track technology management department of DB Netz AG in Frankfurt/Main, Germany. He is a member of numerous German and European technical standard committees, e.g. DIN Standards Committee Railway NA 087-00-01 AA ‘Infrastructure’, DIN subcommittee ‘Ballastless track’ and CEN TC 256/SC 1/WG 46 ‘Ballastless Track’.