18-05-2012, 04:37 PM
CONCRETE CONSTRUCTION INDUSTRY – CEMENT BASED
MATERIALS AND CIVIL INFRASTRUCTURE – (CBM-CI)
CONCRETE CONSTRUCTION INDUSTRY.pdf (Size: 171.18 KB / Downloads: 112)
ABSTRACT
An analysis of the concrete construction industry in Turkey is presented.
The growth trends of the cement manufacturing and ready mixed concrete production
industries are discussed. The expected impact of the new regulations on CE marking of
cement and aggregates, and G marking of ready mixed concrete on the construction industry
are briefly presented. Increasing demands for high-rise buildings in Turkey and contracting
services in foreign countries are discussed. Some examples from application are given on
the use of mineral admixtures, steel fiber reinforced concrete, and self-consolidating concrete.
The state-of-the-art of the research on these applications is discussed in detail. The Marmara
Bosphorus Crossing Project, the deepest immersed tube tunnel in the world, is presented
as an important example of record-breaking mega projects in Turkey.
INTRODUCTION
The cement manufacturing and concrete production industries are significant components
of the Turkish economy. Both industries have been experiencing a growth trend due to the
increasing demand for public housing and high-rise office buildings. New regulations on
the production of concrete and materials used for concrete have been introduced due to
agreement with the EU Customs Union. Increasing demands for high-rise buildings in
Turkey and contracting services in foreign countries demonstrate the quality of the services
offered by the construction industry. On the other hand, the industry demands research on
special applications of concrete, such as self-consolidating (also called self-compacting)
steel fiber reinforced concrete and concrete mixture design with one or more mineral
Dr. M. A. Tasdemir and Dr. Y. Akkaya
THE CONSTRUCTION SECTOR IN TURKEY
The construction sector is known as a “locomotive sector” in Turkey due to it dominating
more than 200 subsidiary sectors. The sector consists of companies engaged in construction
of housing, buildings for nonresidential purposes, and infrastructure; these constitute 60%,
20%, and 20% of the sector, respectively [1]. According to the Turkish Statistics Institute,
in the first nine months of the year 2006, a growth rate of 20.8% was attained in the
construction sector. In the first quarter of 2006, a growth rate of 25.9% was accomplished
[2]. Although the growth rate in the construction sector in 2005 was 21.5%, the share of
the sector in the GNP (Gross National Product) was 4.2%, which is still under the levels
of 5.2% and 4.6% that had been attained in the years 2001 and 2002, respectively [1].
CONTRACTING SERVICES IN FOREIGN COUNTRIES
The values of foreign contracts awarded in 2003 and in 2004 were 3.4 and 5.8 billion USD,
respectively. The service provided to foreign countries by Turkish contractors has increased
rapidly. The value of contracts in foreign countries awarded in 2005 was 9.3 billion dollars.
The target for 2007 is more than 15 billion dollars. In the last 35 years, Turkish contractors
have realized approximately 3500 projects in 65 different countries. The total cost of these
contracts is about 75 billion dollars. In recent years, Turkish contractors have proved their
quality of services, reasonable prices and their emphasis on customer satisfaction all over
the world. Turkey is in third place in the world after the United States and China [1].SUMMARY AND CONCLUSIONS
After the 1999 earthquake in Turkey, the cement and concrete production industries started
to exhibit a fast growth trend. The demand for public housing, high-rise office buildings,
and infrastructural construction projects is increasing. Meanwhile, the EU Customs Union
Agreement imposes new regulations on the production of concrete and materials used for
concrete. Turkish contracting services in foreign countries also exhibit a growing trend.
The growth in the concrete industry is also reflected in academic research through
collaborations. Strategic infrastructural investments, such as the Marmara Bosphorus
Crossing Project, have teamed up with ITU for the development and quality control of high
performance concrete with a controlled cracking risk. Research on special applications
such as steel fiber reinforced self-consolidating concrete and ultrahigh performance steel
fiber reinforced composites has resulted in new product developments.
The cost of the steel fibers used in the production of SFRCs is also important from an
application point of view. Therefore, the volume fraction of steel fiber must be minimized
to obtain an economical mixture by maximizing the equivalent flexural tensile strengths.
Thus, numerical optimization can optimize any combination of either factors or responses.
The price of steel fibers with high aspect ratios is higher than that of the lower ones, but
their performances are contrary to their prices. SFRC producers should seek an optimum
solution since the designer is interested in the equivalent flexural tensile strength, but not
in the price. Additionally, in the determination of the performance classes of SFRCs, the
concrete strength, ductility, durability, and workability in the fresh state will be of concern.