Views: 280 Author: Site Editor Publish Time: 2017-11-08 Origin: Site
The 60th anniversary of AAC production in Poland is a perfect opportunity to draw up a short history of the production conditions and technological development of aerated concrete in Poland, from its origins to the present. This summary will also remind us about the people who have worked to develop the complicated production processes of AAC under enormous pressure of virtually unlimited demand of the building market, especially between 1951 and 1976, when the demand for AAC products in Poland was extremely strong. This paper also underlines the importance of scientifice and research sector, and especially of the Research and Development Centre of Concrete CEBET, which has contributed significantly to the development and present-day popularity of aerated concrete in Poland, Europe and throughout the world.
It all started in 1951, which marks the beginning of autoclaved aerated concrete in Poland. This new construction material has been relatively popular in Sweden, where it was produced since 1930s (Ytong -burnt lime technology, Siporex - cement -based technology) Aerated concrete has been known for its favourable thermal insulation performance, relatively high strength, high resistance to fire, and a friendly microclimate indoors. The launch of AAC production in Poland, consuming raw materials ready available on the domestic market, has contributed significantly to the rigorous recovery and development of the Polish economy post World War II. With the optimum structural and insulating properties of AAC, the new construction material has been quickly accepted and has become one of the most popular wall building materials in Poland. High energy efficiency and low consumption of raw materials in the production process as compared to other wall building materials has been another factor that contributed to AAC introduction on the domestic market.
2. ALL BEGINNINGS ARE DIFFICULT - RESEARCH SECTOR OVERCOMES DIFFICULTIES
The production of aerated concretes in Poland has begun with a Polish -Swedish cooperation, under which the production licence was granted and the first two experimental production lines partly furnished. Between 1951 and 1952, two small factories were commissioned in Reda (Ytong) and Aleksandrow Kujawski. These were experimental facilities for the Polish production technologies of aerated concrete and important training centres for new, large-scale production plants.
The beginnings of AAC production in Poland have been difficult, although based on licensed technologies from experienced Swedish companies. Raw materials available on the domestic market were quite different from the technological requirements of the licensed production methods. Polish engineers have been therefore working to customize the production technologies to the raw materials available in Poland. These difficulties have been overcome with joint efforts of Polish technology engineers, experts have been trained, and unique Polish production methods of aerated concrete have been developed, customized to different compositions of raw materials:
- Lightweight belite concrete (BLB),
- Aerated silicate-based concrete (PGS)
- Slow-setting silicate-based concrete (SW)
- Universal technology of AAC production UNIPOL.
The development of UNIPOL has been a major achievement. Apart from the use of a mixed binding material (lime and cement mixed with aggregate) and different types of aggregates (quartz sand and fly-ash), the production process has remained considerably flexible. In 1961, a patent was granted for the UNIPOL technology.
The technological works have been conducted by the Central Lightweight Materials Laboratory (Centralne Laboratorium Lekkich Tworzyw, CLLT) established in 1954 in Warsaw, and the Aerated Concrete Technological Workshop operating since 1955 under prof. Jozef Szamota. CLLT was the turning point in the production of aerated concrete in Poland. It has been conducting research and experiments to improve production technologies and applications of lightweight concretes. The Laboratory was managed by prof. Antoni Paprocki, Eng., PhD until 1963. The key members of Antoni Paprocki's team of experts are presented in the following cartoon.
The team which designed new AAC technologies was also supported by Waclaw Gora and Jerzy Domaszewski, Eng., MSc as well as Polish experts in cement production technologies from the AGH University of Science and Technology: prof.Jerzy Grzymek, PhD, prof. Wieslaw Kurdowski, PhD, and Stefan Pieczara, Eng. MSc. In 1971, the CLLT Laboratory was renamed into the Research and Development Centre of COncrete CEBET, presided over by Jerzy Widera, Eng., (1966 - 1981), and succeeded by Hanna Jatymowicz, PhD (1981 - 1990). Hanna Jatymowicz, PhD, used to be the Vice-Director for aerated concretes between 1954 and 1980.
Experts have introduced numerous improvements in AAC production, for example, they have managed to eliminate the process of clay powder degreasing by roasting it in roasting plants, and the clay was replaced by surfactants (used until present day). Moreover, molasses and sugar used in Swedish fly-ash technologies have been replaced with gypsum dihydrate, which balances concrete mix growth and binding time and provides for the optimum strength of aerated concrete.
3. DYNAMIC DEVELOPMENT
After the licence agreements have been terminated, the production of aerated ocncrete has been developed according to specific Polish technological methods and production line configurations at new production plants.
In orderto be able to improve the technical quality of aerated concrete produced at production plants which have become increasingly modern, the basic scientific, research and experimental tasks have been entrusted to the Research and Development Centre of Concrete CEBET, which acted in close cooperation with a specialist design center of aerated concrete production facilities, renamed into Concrete Industry Designing Office BIPRODEX in 1964, and Zjednoczenie ZERMB, the key producer and entity specializing in the construction of machines and installations for aerated concrete production facilities. The aerated concrete industry has continued to develop according to the same pattern until 1982, when industry-specific trade asociations were put into liquidation. Fortunately, the Research and Development Centre of Concrete CEBET has continued to exist, although its organizational background has changed considerably.
Research and design activities related to the new applications of aerated concrete have been still handled in close cooperation with the Research and Development Centre of Concrete CEBET, mainly by the Building Research Institute and the Research ＆ Design Ofiice of Housing Development (renamed into the General Construction Research and Design Center), responsible for the majority of new construction products introduced on the market.
Consequently, convenient conditions have been created for the development of AAC production formula and its applications. With each new production plant, the production process has been increasingly modern and closer to the global production standards prevailing at that time. The Polish school of aerated concrete has been borm, which has developed unique AAC production technologies used in Poland, all over Europe and in other countries around the world. The research centres, including the Research and Development Centre of Concrete CEBET, have been also involved in the supporting the export of Polish aerated concrete plants. Between 1956 and 1986, Poland exported 36 aerated concrete production plants with the total annuall production capacity of over 4 million m3 of AAC, mainly to Russia, Slovakia, Czech Republic, Mongolia, China, India, Egypt, Hungary, Romania, Germany and Irap. In order to avoid licence-related problems that Poland used to experience, CEBET has been conducting comprehensive tests of foreign raw materials in order to develop customized production technologies and formulas for the exported production plants. In late 1950s and at the beginning of 1960s, CEBET wasfitted with a research laboratory and other technical facilities to be able to carry out comprehensive experiments independently of the production plants. This is where new machines and equipment have been tested, i.e. cutting machines, new autoclaves for new production plants, and new shorter hydrothermal processing cycles of aerated concrete have been developed to the later introduced to the production lines. In the initial development period of aerated concrete production in Poland and in cooperation with "Bukowa" Lime Production Plant, the Research and Development Centre of Concrete CEBET has designed a lime burning technology to provide optimum lime parameters used in the production of aerated concrete, and has selected the best cement type (the belite concrete was no longer produced). The production of aerated concretes in Poland (and to some extent abroad-36 AAC production plants have been exported on a turnkey basis) has been developed by joint effort of thousands of people, both scientists and blue collar workers. The Polish school of aerated concrete has been created by prof.Antoni Paprocki, Eng., PhD (who also published a book entitled "Aerated Concretes") and Hanna Jatymowicz, PhD, with the contribution of Jerzy Widera, Eng., PhD (the Director of Research and Development Centre of Concrete CEBET between 1966-1981), prof.Jerzy Grzymek, Eng., PhD and prof.Wieslaw Kurdowski, Eng., PhD from the AGH University of Science and Technology. Their achievements in the development of AAC production technology have been later consolidated and further broadened by other scientists, process engineers, and designers of production systems and facilities, cooperating with CEBET in Warsaw, the building Research Institute in Warsaw, and the AGH University of Science and Technology, in particular: Janina Siejko, Eng., PhD, Genowefa Zapotoczna-Sytek, Eng., PhD (who wrote Autoclaved Aerated Concrete Technology along with Hanna Jatymowicz, PhD), prof.Jan Malolepszy, Eng., PhD, Seweryn Szewczyk, Eng. - Vice-President of Concrete Industry Association (Zjednoczenie Przemyslu Betonow), Andrzej Plodowski, Eng., PhD, Antoni Luba, Eng., MSc, Jerzy Pietkiewicz, Eng., MSc, Miroslaw Protasewicz, Eng., PhD, Antoni Luba, Eng., MSc, Jerzy Pietkiewicz, Eng., MSc, Miroslaw Protasewicz, Eng., MSc - designers of AAC production equipment, Jerzy Domaszewski, Eng., MSc - Deputy President of Design Ofiice for Concrete Industry Biprodex, and Wladyslaw Garczynski, Eng., MSc, designer at AAC production plant representing Biprodex.
With the work and engagament of the aforementioned individuals and other experts, AAC production plants have been established and developed in Poland which represented state-of-the-art technologies at that time, offering high production capacities and highly advanced technologies based on practical experience gained in the operation of the first production plants in Reda and Aleksandrow Kujawski.
Between 1953 - 1962, 9 production plants were commissioned: Warszawa-Zeran, Laziska Gorne, Solec Kujawski, Lubartow, Lodz, Stalowa Wola, Bielsko Biala, Warszawa-Siekierki, and Skawina. Typical features of the new plants:
- production technologies of BLB, PGS, SW products,
- machines and installations partly based on solutions imported from Sweden (from 1959 - machines and installations designed by ZREMB),
- moulds: h = 24 cm, 600cm long,
- spring-type cutting machines,
- concrete density: 900 - 700 kg/m3 (in a dry condition),
- product protfolio; small-size construction elements, reinforced elements (post-autoclave and surface processing).
Based on further scientific achievements, 13 new production plants were commissioned between 1964 and 1971, representing a new Reda generation of production facilities (named after the first production plant representing a new generation plants, opened in 1964 in Reda. Reda-type production facilities: Reda II, Lidzbark Welski, Dlugi Kat I and II, Sniadowo, Powodowo, Milicz, Glogow Malopolski, Podniesno, Pila, Szczein Rurka, Gorzkowice, Zelislawice, Niegocin and a small plant in Stezyca. These new plants have been based on the Polish Unipol technology and new machines :Typical features of the new plants:
- moulds: h = 60 cm, 300 cm long,
- feed ＆ turn cutting machines (advanced),
- concrete density: 700 - 500 kg/m3,
- product portfolio; small-size and reinforced elements.
The quality of products produced at Reda-type plants have been significantly improved in terms of material parameters and its appearance.
At a later period, based on experiments and studies conducted at CEBET in cooperation with a variety of experts, the assumptions of 4 new generation Pulawy-type production plants have been developed (Pulawy, Kozienice, Lagisza, Bytow). The new type of plants was named after the first of 4 new plants in Pulawy, commissioned in 1971.
The Pulawy production plant was furnished with 60 cm x 600 cm moulds and a new type of cutting machine, KRG (tested at a special test stand in CEBET) for longitudinal, transverse and horizontal cutting of concrete blocks, maintaining optimal size tolerances. Unipol sand and fly-ash technology has been in use. The concrete density varied from 700 to 500 kg/m3. A production plant in Ostroleka was the only plant commisiioned in 1970 (in 1976) employing both, foreign and Polish solutions. Specific installations have been licensed by Calsilox, a Dutch company (transfer of concrete mix with a special gripping device from the moulding station to the cutting station). The installations were delivered by Skoda-Eksport from Czechoslovakia, and licensed by a Dutch company. The concrete density varied from 700 to 500 kg/m3. Product portfolio: small-size elements and reinforced planks.
The production plant in Pulawy has been adapted to the production of small-size elements, and a comprehensive protfolio of reinforced elements.
In general, the product portfolio has been broadened along with new developments in th e AAC production technology. The first AAC plants in Poland produced concrete blocks and panels. With the development of production technology and in each new production plant, new types of reinforced elements have been introduced in response to the global trends and the requirements of the domestic construction industry. The new products have been implemented for use under the supervision of the Research and Development Centre COBPBO. Specific construction elements and their applications have been designed in close cooperation of experts from the Research and Development Centre of Concrete CEBET (Juliana Bodzaka, Eng., MSc) and the General Construction Research and Design Center COBPBO (prof.Bohdan Lewicki, Eng., PhD, Wladyslwa Sieradzki, Eng., Roman Gajownik, Eng., PhD) and the Aerated Concrete Production Plant supervised by the Concrete Industry Association. In late 1950s, medium-size reinforced elements have been introduced, and in 1960s and 1970s - a new portfolio of reinforced planks, 300 cm and later 600 cm long. In the years that followed, the production technologies and installations have been modernized to be able to further expand the AAC product portfolio with floor slabs, floor and roof slabs for single-family houses, partition walls and wall planks for single-family houses, industrial facilities, and public buildings (nurseries, kindergartens, motels, etc.)
The production of aerated concrete in Poland has been developing and expanding ever since 1951 until 1989. The period 1960 - 1975 marks the most dynamic development of production capacities - the production volume rose from 0.7 million m3 in 1960 up to 5 million m3 w in 1975. Between 1951 and 1976, Poland produced over 25 million m3 of aerated concrete, and built hundreds of thousands of blocks of flats. The development of AAC can be attributed to the engagement of people representing the research sector and the construction industry. After 1978, the production fell slightly due to the deterioration of production capacities of AAC production plants caused by waer and tear and lack of investment.
From the beginning of 1970s until the beginning of 1980s, AAC production intensification and development has slowed down since the Polish authorities decided to focus on the construction of "factories of houses" in response to the huge needs of the Polish society. The production AAC and small-size elements have been side-tracked for several years. However, still over 280000 flats were built in 1978 - a record which has never been equalled.
Please be reminded that the Polish economy has been centrally planned and controlled until 1989.
Another era of multi-family housing in Poland has been dominated by large-size integrated ready-made AAC panels (production plants in Pulawy, Lagisze).
A variety of anti-corrosive coatings have been designed and introduced by the Research and Development Centre of Concrete CEBET (latex0cement, asphalt, Berox coatings.) The works on new coatings of reinforced elements have been supervised by Hanna Jatymowicz, PhD and Krystyna Walczak, Eng., PhD.
Still, the share of reinforced elements has been small and amouted to 2% of the total AAC construction volume. The demand for small-size elements has been so high that the production plants were not particularly interested in expanding the product portfolio (which required a most disciplined approach to the production process and excellent quality raw materials), although the production formulas and technologies of new products have been already designed.
The research sector continued to improve the aerated concrete production technologies in order to reduce the amounts of raw materials, energy and labour consumed by the production process, along with the introduction of new raw materials, in particular:
- experiments on introducing a separation process in the raw material milling station;
- designing and introducing a polyurethane coating (EPU) in wet mills, pumps;
- designing and introducing a keyboard cutting machine, and a station where concrete mix excess was removed;
- modernization of sludge milling station;
- modernization of autoclaved and reducing autoclave corrosion (anti-corrosion coatings, structural solutions);
- automation and optimization of autoclave processing and systems operating on waste heat;
- automation of concrete mix pre-processing and metering stations;
- development and implementation of an aluminium paste formula in AAC production.
Fly-ash concrete formulas have been also continued to be developed since fly-ash has been one of the main raw materials in a variety of AAC production plants. The experiments and research have been implemented for both, existing and planned AAC production plants. Detailed physical and chemical requirements for fly ashes have been determined. All research activities, laboratory tests and comprehensive technical processing using different fly ashes have taken place at CEBET facilities.
New production technologies of aerated concrete have been developed using fly ashes from hard coal combustion, brown coal from dry ash removal, fly ash from burrows, and waste gypsum from power engineering and chemical industry. CEBET has been cooperating with AAC production plants to develop a waste-free desulphurization process in in-house boiler-rooms, industrial waste utilization, a safe aluminium pre-processing and metering station, as well as improved formulas of lightweight concrete with post-production waste management.
CEBET also continued to invent new applications of lightweight aerated concrete at the research facilities of CEBET, and later during implementation tests at production plants. Production, storage and transportation recommendations for lightweight concrete have been also developed.
Based on the outcomes of research conducted by CEBET on lightweight concrete types, a new production plant of high-quality aluminium powder Benda-Lutz - Skawina has been designed.
In addition, exemplary implementations in single-family houses have been shown at the Permanent Construction Exhibition, involving lightweight concretes and low thermal conductivity mortars developed by the Research and Development Centre of Concrete CEBET.
The authorities in Poland have been at that time focused primarily on the "Factories of houses", and the managers of underfunded concrete plants have attempted to obtain funds to develop and modernize the AAC production industry. Concrete Producers Association was established in 1982 from the Concrete Industry Association, managed by Stanislaw Petrykowski, the President, and Seweryn Szewczyk, Vice-President, along with numerous managers of production plants: Romuald Sadowski - former Director of Prefabet Gorzkowice; Wlodzimierz Kedziorek - former Director of Prefabet Warszawa; Wojciech Gumkowski - former Director of Prefabet Gdansk; Tadeusz Pawlowicz - former Director of Prefabet Elk; Stefan Matuszkiewicz - former Director of Prefabet Powodowo; Jerzy Zebrowski - former Director of Faelbet Warszawa; Ryszard Smilek - former Director of Prefabet Skawina; Edward Myszka - former Deputy Director of Prefabet Warszawa - subsequently the President of Faelbet Warszawa; Roman Muszynski - former Director of Prefabet Lidzbark Welski; and Mieczyslwa Sobonia, a co-author of this paper, The subsidies were awarded in a Dicision no.8 of the Minister of Construction and Construction Products Industry of 30 th June 1983. Each aerated concrete block sold has been co-funded by the government. The funds collected have been intended for the renovation of production plants and further research. As a result, the production capacities of AAC production plants have been partly restored, and two new production plants have been commissioned.
The production volumes of aerated concrete have been on the rise until 1989 to drop between 1990 and 1992 as a result of an economic crisis that affected the Polish construction industry. Despite the downturn, the research sector has continued its development works on AAC products, technologies and production installations. The Research and Development Centre of Concrete CEBET continued to work on the computerrization of AAC production process (pre-processing and metering of starting materials, remote settings, identification of bases, moulds, and casts, process visualization, automatic measurements of the properties of raw materials, semi-finished products and finished products). In the earlier period, Polish researchs have been cooperating with experts from Czechoslovakia. Some of the new solutions have been introduced when the older types of production plants havebeen modernized and renovated.
4. NEW GENERATION PRODUCTS
From the middle of the 1990s, the Polish aerated concrete construction plants have been renovated and modernized. The modernization process has correlated with the improvement in the financial standing of companies in Poland as a result of economic and political changes, technological solutions which have been already available, and with the establishment of the Concrete Producers Association in 1994 with a separate Aerated Concrete Section. At the beginning, the Association has been establishing professional and personal relations and sharing experience among concrete producers, having in mind the enormous effort that needed to be contributed by the concrete industry in general and by each concrete producer individually. The AAC Section was first presided over by Maciej Burasiewicz - the Director of PREFABET Warszawa, and then, until the end of 2009, Jerzy Michalak - the Driector of PREFBET Sniadowo, followed by Jacek Kosim - the President of PREFABET Group, and currently Marek Malecki - the President of SOLEBT Group. Soon after the Association was established, the technical and technological undertakings have been implemented mainly by senior managers of concrete production plants, which later proved very successful. AAC Section members used to visiti the AAC production plants on a regular basis to the best experience and know-how. This successful period lasted until 1998 and brought about many achievements in the AAC production sector. Until then, AAC producers have been implementing numerous patented and innovative solutions in close cooperation with CEBET.
The modernization process involved automation and computerization of the pre-processing, metering and cutting processes (milling, dosing and cutting stations), which proved decisive for the size precision and high-quality of finished products.
Moreover, palletizing and packaging processes have been introduced in product reload sections. At the cutting station modernization process has been jointly financed of AAC producers, members of the Association, and designed by AAC experts (cutting stations of 3 and 6 m long blocks). PREFABET Kolbuszowa S.A. - currently SOLBET Kolbuszowa S.A. has specialized in cutting 3 m long blocks, whereas SOLBET ZREMB S.A. operated cutting stations of 6 m long blocks. The modernization process of AAC production plants and of the cutting stations in particular has been the turning point in the modernization of the AAC production technology in general. AAC production plants have started to produce new generation construction products, including profiled elements representing the highest construction standard (measuring accuracy of +/_ 1.0 - 1.5 mm, for 1 - 3 mm thin joints). Reinforced aerated concrete lintels have been also introduced (Gold Medal at the BUDMA International Construction Fare in Poznan for SOLBET), which considerably simplified the construction process.
Along with aerate dconcrete production plants and in cooperation with the Building Research Institute in Warsaw, CEBET has undertaken efforts to design and introduce new AAC applications. Accordingly, CEBET has been conducted comprehensive studies on brickwork made of AAC blocks, co-financed by AAC producers. On the basis of the study results, the current properties of AAC blocks have been defined and compared to the present-day requirements laid down by new industrial standards (strength parameters, thermal properties, sound reduction performance, fire resistance, etc.). Polish products were shown to be equally successful as aerated concrete elements produced in West European countries. The new generation products (presented at numerous conferences) combined with thin joint and low thermal conductivity mortar technologies can be used in the construction of buildings which meet the most demanding energy efficiency requirements.
In analysing AAC production technologies, the production process and the applications of aerated concretes were found to contribute to reduced CO2 and NOx emissions, and to comply with the requirements on sustainable development.
Despite the global economic crisis in 2008 and 2009 and production drop in numerous sectors of the Polish economy, the aerated concrete production was down by mere 11.1% and 20%, respectively, against the production peak in 2007 of 5.55 million m3.
Aerated concrete has been a very attractive product commonly used in the construction of walls (approximate share of 41%), and international companies have started investing in the Polish AAC production plants, which considerably changed the organization and ownership structure of the Polish AAC production plants, which considerably changed the organization and ownership structure of the Polish AAC production sector. SOLBET Group remains the leading producer of aerated concrete in Poland, followed by H+H, XELLA and PREFABET GROUP. In 2009, two modern AAC production plants were commissioned (Reda III of the PREFABET Group, and BRUK-BET).
There are currently 32 AAC production plants operating in Poland. The density of AAC products varies from 300 kg/m3 to 1000 kg/m3. However, CEBET and the AGH University of Science and Technology along with concrete producers continue their efforts to reduce the concrete density. In addition, research teams from CEBET and AGH University of Science and Technology, in cooperation with the Institute of Power Engineering have been conducting comprehensive studies on new generation fly ashes (produced of carbon and biomass combustion, and carbon combustion in fluid boilers) of different characteristics as compared to siliceous fly ashes produced using the traditional combustion methods. The studies conducted so far have been awarded a gold medal with distinction at the 4th International Warsaw Exhibition of Innovations IWIS 2010, and a silver medal at BRUSSELS INNOVA 2010, the World Exhibition on Invention, the 59th Research and New Technologies.
With a few exceptions, AAC producers are members of the Polish AAC Producers Association, which has been actively participating in the activities of the European Autoclaved Aerated Concrete Association EAACA.
The total AAC production volume in member states of EAACA amounted to 16300 thousand cubic meter in 2009, and approx. 40 million cubic meter worldwide. Poland is the leading producer of AAC in Europe, with a 10% share in the global production.
- The development of autoclaved aerated concrete in Poland, especially between 1960 and 1976, has been driven by huge deficit of construction materials in the period of redevelopment after World War II, along with exceptionally favourable construction and insulating properties of AAC. The decision to introduce AAC production in Poland brought about a very positive outcome.
- The establishment of the Cntral Laboratory for Lightweight Materials, later renamed into Research and Development Centre of Ceramics and Building Materials CEBET in 1971 was the turning point in the history of AAC production in Poland. CEBET has been responsible for implementing the basic research, development and implementation activities supporting the technical development and improvement of the AAC industry. Within the past 60 years, CEBET activities have contributed to a large extent to the development of AAC production sector, in close cooperation with a number of research and design centers, including AGH University of Science and Technology in Krakow, BOPRODEX, Zjednoczenie ZREMB, Association of Concrete Industry (Zjednoczenie Przemyslu Betonow), ITB, Building Research Institute and the Research ＆Design Office of Housing Development (Biuro Studiow i Projektow Typowych Budownictwa Mieszkaniowego) (later renamed into COBP Bud. Ogolnego). In activities related to the export of AAC production technologies and facilities, CEBET along with other research centers has been cooperating with POLIMEX-CEKOP and FABEX-ZREMB. Within the past few years, AAC research sector (CEBET, AGH University of Science and Technology) has been cooperating with AAC production plants and the Concrete Producers Association in research activities and implementations.
On behalf of other researchers from the Research and Development Centre of Concrete CEBET, recently renamed into Concrete Research Center CEBET at the Institute of Ceranmices and Construction Materials ICiMB, presided over by Stanislaw
Traczyk, PhD, we here by declare and confirm our willingness to continue our cooperation with the Concrete Producers Association, concrete production plants, and other research centers.
- The initial 20 years of AAC in Poland, in the reconstruction period after World War II, the main efforts have been devoted to providing sufficient volumes and quality of aerated concrete;
- With each new production facility, the production process has been increasingly modern and closer to the global standards prevailing at that time. As many as 36 turnkey production facilities have been exported, which was an unprecedented project supervised by POLIMEX-CEKOP and FABEX-ZREMB. In late 1980s, when the Polish construction sector collapsed, the AAC sector stagnated and the modernization process of AAC production plants came to a halt.
- In mid 1990s, the AAC production plants have started to renovate and modernize to produce new generation products exhibiting excellent tolerance properties, high-quality appearance and optimum technical parameters.
- AAC continues to develop. Its technical properties are continually improved, and the demand for AAC products has been increasing, driven by sustainable development requirements. AAC products have been successfully applied in the construction of energy-efficient and passive houses.
- In the years to come, AAC needs to be further developed in consideration of following factors:
1. Increased share of lightweight and ultra lightweight concretes, especially as a non-combustible and safe insulating material. It would be perhaps possible to further improve admixtures to increase the strength of AAC matrix and to further reduce AAC densities.
2. Continued efforts to cut down energy consumption in AAC production to make it more energy efficient.
3. Comeback of prefabricated reinforced AAC elements.
4. Popularization of innovations in AAC applications among designers, investors (bad workmanship can severely affect the image of AAC).
5. Research activities involving new raw materials in the light of the contemporary market tendencies in Poland (new generation ashes, multi-components cements,etc.)
In addition to the foregoing, highly qualified personnel need to be educated and trained at research centres and aerated concrete production plants under close cooperation with the concrete industry and the academic sector. Cooperation in this respect has been already initiated by the Concrete Producers Association and the Department of Construction Materials Technology at the AHG University of Science and Technology in Krakow.