AN IRREPLACEABLE MATERIAL

I wouldn’t like a situation where one of the two persons who invited me here would ask: “Why did you invite him here?”, and the other: “Why did you agree to that?” I will tell you something about the future, although these will be just some guidelines and forecasts. I am an old man and it is hard for me to talk about it. This morning, at the Cracovia Hotel, someone asked me whether I was this Nevill who wrote the book in 1973. When I confirmed, my interlocutor responded: “And I thought you were already dead,” – this was the story said by Professor Adam Neville, a world authority on concrete and author of the book Properties of Concrete, the first Polish edition of which coincided with the conference “Concrete at the turn of the new millennium”.

The Conference “Concrete at the turn of the new millennium” organized by Company POLSKI CEMENT and the Polish Cement and Lime Association took place on November, 9-10. Over 300 scientists, designers and technologists came to “Manggha” Centre of Japanese Art and Technology in Krakow. The Conference was also an opportunity to celebrate the 10th Anniversary of the Polish Cement and Lime Association.

CONCRETE: MODERN AND ECONOMICAL
‘Our conference has the character of a meeting of scientists with practitioners. It gathers the greatest manufacturers of cement, concrete, paving stones and prefabricated elements. Everyone perfectly understands the necessity of activities promoting concrete as a modern and economic construction material,’ said Andrzej Balcerek, the President of the Polish Cement and Lime Association during the conference opening ceremony.
The objective of the conference was exactly to demonstrate the present opportunities offered by concrete – a material that perfectly joins the construction and architectural functions.
In the opinion of Dr Jan Deja, the President of POLSKI CEMENT, concrete is presently high tech. ‘On the other hand, there is a general opinion that it is a primitive material and everyone can make it. We have gathered here to change this view,’ said President Deja.
The conference was divided into five theme blocks: technology of concrete, concrete in architecture, concrete in transport construction industry, durability of concrete and new generation concretes.

CONCRETE: IDEAL IN THEORY, IMPERFECT IN PRACTICE
A special guest at the conference was Professor Adam Neville from the UK. Professor Neville, a world authority on concrete, came to Krakow in relation to the promotion of the Polish version of his book Properties of Concrete. The book is the most popular worldwide monograph on technologies and properties of concrete. From the first edition in 1963, Prof. Neville has been systematically supplementing his work. It has been translated into twelve languages. Polish edition was publish for the first time in 1973. The present edition prepared by POLSKI CEMENT is therefore the second edition. It has been prepared on the basis of the fourth English edition. The book is designed for a broad range of readers: designers of concrete technologies and constructions, forces in charge of structure maintenance, concrete researchers and students of construction and similar departments.
During the conference, Prof. Neville delivered a lecture entitled “Considerations on durability of concrete structures”.
‘Concrete is a patient material. My wife believes that I am less patient than concrete. I want to tell you that for many years I was wrong as to consideration on durability of concretes and structures. Being an old man I do not have to worry that there will be a day when someone proves that I was wrong as I will no longer be there. When designing structures, I apply by parallel my favourite definition of the safety coefficient: the number of years to retirement plus two,’ said Prof. Adam Neville in his lecture. ‘The thing is that concrete is a great material, but the sum of all accompanying activities is insufficient. There is a general conviction that concrete can be laid by any fool. In many countries one does not even notice that the profession of a concrete maker requires training, exams and certifications. It is often believed that anyone who is free at the moment can be directed to casting or compacting of concrete. How to change that? In 1967 we changed the imperial system to metric system - SI. Our government then has a wise idea and ordered that all designs must be made in the new system. When an agency took a design project, it did not want to make it in old units even for their good customers. What conclusions can be drawn from that for our purposes? Perhaps agreements should contain a provision that the team for concrete casting must feature one qualified person. A year later an agreement may require that at least one third of employees have such qualifications. And so on, until there are no longer unqualified concrete-makers. We must take care of the properly qualified personnel dealing with concrete works. Then we will have proper techniques of concrete casting, compacting, finishing works and proper concrete maintenance. If we don’t do something about it now, concrete will be ideal in theory, but imperfect in practice.
What is necessary to ensure proper durability of concrete structures? ‘Application of appropriate components, together with various cement binders and admixtures, through good or very good performance, beginning from dosing, through mixing, transport, casting, compacting, until maintenance,’ said Prof. Neville. ‘We cannot assume that the achievement of the required strength will ensure the appropriate durability, but we also should not deal with durability only in the aspect of strength.’

CONCRETE: A DURABLE AND ECOLOGICAL MATERIAL
In very interesting lectures devoted to durability of concrete it was stressed that the key to the appropriate lifecycle of concrete lies in the technology of its performance and the appropriate composition of components of the concrete mixture.
‘The latest achievements in the area of high-performance concrete are a great step forward as concerns transforming concrete into a modern material of improved properties and durability,’ said Prof. Andrzej Brandt during the session on “New generation concretes”.
High-performance concrete is used for the highest buildings worldwide. According to Prof. Andrzej Ajdukiewicz, in the developed countries, present concrete, including HPC, is jokingly referred to as a 4D material, which stands for “difficult, dangerous, dirty and desperately underestimated”. ‘It is believed that with time it is possible to evolve the concrete technology towards the “high-tech” material group. So far, this may only refer to the technology of ultra- high-performance concretes, or UHPC,’ said Prof. Ajdukiewicz.

CONCRETE: STONE OF PRESENT TIMES
‘When dealing with concrete, we may talk about its technology, structure or architecture, but we cannot separate this triad,’ said Prof. Dariusz Kozłowski in his lecture entitled “Concrete and architecture. Gesamtkunstwerk by Carl Scarpa in San Vito di Altivole”. Lectures in the block “Concrete in architecture” were delivered by the best Polish architects.
‘One may think about concrete in the occupational-and-practical, theoretical, scientific or artistic aspect. Carlo Scarpa does not divide these domains. The Italian architect, the master of architectural detail, creates his concrete work with the sensitivity of an artist dealing with musical matter,’ said Prof. Kozłowski. ‘Concrete as a structure remains invisible in Scarpa’s architecture. It has a role of modern stone, worked with mastery, and in such a manner juxtaposed with other materials.
‘For architects who praise honesty in architecture, concrete is an irreplaceable material. However, when talking about reinforced concrete and concrete, one must state that it is good that Krakow was built before reinforced concrete was invented. It turns out that after ten years from the systemic transformation, there is no company in Poland which would perform architectural concrete well. There are attempts, yet each time this requires great effort,’ said Stefan Kuryłowicz. ‘On many investments, contractors claimed that there could not e.g. make the formwork, and we then had to resign from concrete. In turn, Japanese make perfect architectural concrete.’
According to Konrad Kucza-Kuczyński, authentic sculpting property of concrete offers opportunities of an architect’s dreams come true. ‘Unfortunately, concrete has not very good associations with residential building. Architects’ work has been burdened with the 170 Soviet house factories. Probably two generations grew in concrete blocks of apartments,’ said Konrad Kucza-Kuczyński. ‘Nevertheless, there are very interesting realisations of residential buildings even from the 1970s. In turn, the recent investigations use not only its varied texture, as we found out during the hundred years, but also the opportunity of authentic concrete sculpting. We do not know what the concrete in the residential architecture of the 21st century will look like. Will it be present there at all?’