Hazır beton tesislerinin verimlililk araştırması

Abstract

İİk olarak 1903 yılında Almanya'da üretilen hazır beton, geleneksel şantiye betonuna olan üstünlükleri nedenile, Amerika ve Avrupa'da yaygın olarak kullanılmaktadır. Ülkemizde ise, ilk olarak Ankara'da 1976 -1977 yıllarında kurulan hazır beton firması, yüklenicilerimizin ilgisizliği karşısında kısa bir süre üretim yapıp faaliyetine son vermek zorunda kalmıştır. 5. Beş Yıllık Kalkınma Planına dayanarak kaliteli inşaat malzemelerinin özendirilmesi, bütçe dışında oluşturulan toplu konut fonu kanalı ile inşaat sektörüne kaynak aktarılması, hazır beton tesislerinin sayısını artırmıştır. İlerleyen yıllarda, yerli ve yabancı çimento yatırımcıların pazarlama ve katma değer artırıcı özelliği nedenile bu sektöre yatırım yapmaları, fiyatların geleneksel şantiye betonu düzeyine inmesine (rekabet) neden olmuştur. Hazır beton firmalarının rekabet nedenile karlı işletmeler olabilmesi ancak tesislerin kuruluş aşamasında hazırlanan fizibilite çalışmasına (istem / kapasite dengesi) ve kurulduktan sonraki verimliliğine bağlıdır. İstanbul'da faaliyet gösteren hazır beton tesislerinin verimliliğini ölçmeye yönelik olan bu araştırma, ilgili kişi ve kuruluşların (Hazır Beton Üreticileri Derneği) desteğile saha çalışmasına dayalı olarak yürütülmüştür. Anketler sonucu elde edilen bulgular, tesislerin teknolojilerine, kuruluş yerlerine, taşıma uzaklıklarına, yatırımcılarına (yüklenici, agrega satıcısı, yerli ve yabancı çimento üreticileri) göre değerlendirilmiştir. Bununla beraber, kamu yönetiminin verimlilik üzerine etkileri de incelenerek çelişkiler açıklanmıştır. Sektörde başlayan kartelleşme bazı firmalar için verimliliğin yararına, diğerlerinde ise (yükleniciler) zararına olmaktadır. İkinci tür firmaların faaliyetlerine devam etmelerinin en büyük nedeni, kendi inşaatlarında beton kullanmaları ve devletin kuruluş aşamasındaki özendirmeleridir. Sektör hızla gelişmesine karşın, bağımsız girişimciler için (yüklenici, çimento ve agrega üreticileri dışında) çekici olmaktan uzaklaşmıştır.

Fresh concrete that is prepared and mixed outside of the site (and delivered at mixed state) is called ready-mixed concrete. The term of ready-mixed concrete not only means industrial concrete but also it should be sold to a contractor as a good. Therefore, if a contractor makes his own concrete at his industrial plant, it does not mean that he is using ready-mixed concrete. There are many advantages of ready-mixed concrete over traditional concrete. The most important of them are given below: a) The faults because of human factor does not exist at the production of ready-mixed concrete. b) The material loss is minimum. c) Not existence of the concrete plant on a site saves place for the contractor. d) It is not necessary qualified workers on the site. e) The strength of ready-mixed concrete is very high compared to the traditional concrete. f) Buying by wholesale of raw materials is economic for ready- mixed concrete producers. g) The ready-mixed concrete may be used even the weather conditions are very bad. h) Kraft cost vanishes if the ready-mixed concrete is used. The research made at sites, where the traditional concrete is used in 1991, shows that the concrete strength is under the acceptable limits. However, the ready-mixed concrete is not used widely even the many advantages it has. Therefore, government improved the uses of ready- mixed concrete by making laws and acts. The most important of them were given below in chronological order i) Prime minister Turgut ÖZAL created a concept called "Dwelling Fund", ii) Transportation of the ready-mixed concrete plants to Turkey was permitted to contractors who were in North Africa and Middle East, iii) Government sold the cement factories to French investors. As a result of this block-selling, French investors enter the ready- VI mixed concrete sector to sell their cement because of value added of this product. These laws and acts encouraged the contractors to use the ready- mixed concrete. When it is examined in the viewpoint of price of ready- mixed concrete, it is obvious that the ready-mixed concrete should be expensive compared to the traditional concrete because of the machines and equipment. However, the price of ready-mixed concrete with respect to price of cement is continuously decreasing. 1.00 0.75- x 0.50- 0.25- 0.90 0.90 0.90 ü 0-87 İ0.86 İ0.87 I0.83 0.80 (0.77 0.77 0.77,_0.73_ Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec W Figure 1 : The ratio of ready-mixed concrete price to cement price (1992). For the analyzing of this decreasing price, a prestudy was made at Construction Management Division, Civil Engineering Faculty, Technical University of Istanbul. The subject of this prestudy was "profitability of ready-mixed concrete plants". Istanbul branch of Society of Civil Engineering organizes a congress about national concrete, since 1992. The subject of the third one, in 1 994, was about ready-mixed concrete. Therefore, Turkish Ready-Mixed Concrete Association announced that they would support the researches about this subject. This situation encouraged the researcher to research about "Profitability and Productivity Analysis of Ready-Mixed Concrete Plants". Researcher interviewed with some members of this association. After these interviews it is concluded that it is not possible to study about profitability because of the inexistance of standard accounting system. Therefore, the subject of this research was limited to only "Productivity Analysis of Ready-Mixed Concrete Plants". After this limitation, the researcher interviewed with the general secretary of association. The association wanted to create a database about production technology of ready-mixed concrete. Then, a questionnaire form was prepared by using the questionnaire form of British Ready-Mixed Concrete Association- (B.R.M.C.A.), Quality Vll Assurance Certificate of Turkish Institute of Standard, and research report of European Ready-Mixed Concrete Organization (E.R.M.C.O.). These questionnaire forms were filled by 13 ready-mixed concrete companies' staff, and 28 ready-mixed concrete plants' staff thanks to researcher and 10 students who were studying undergraduate thesis at Construction Management Division. While the questionnaire forms were filling, it was seen that the data given by staff of the companies and plants, which are not organized, are not reliable. Statistical data about ready-mixed concrete has been published since 1 992, however European Ready-Mixed Concrete Organization (E.R.M.C.O.) began to publish the same kind of statistical data many years ago. The units of a ready-mixed concrete plant are a building, concrete central with adequate capacity, transmixers, concrete pumps, trucks, laboratories, maintenance center, and offices. There are three types of ready-mixed concrete central, namely vertical, horizontal, and movable central. The horizontal ones are divided into two subgroups, star shaped and inline shaped. Each type has some advantages over others in some conditions (winter conditions, storage volume, weighting capacities, etc.) ( n P = ere2 lai-A.+StyBjfT Po = theoretical capacity at ei, e2, a, b = 1.0 P = annually plant capacity en = external factor (ei < 1.0) e2 = internal factor (e2 < 1.0) a = worker quality b = machine quality A = number of hand workers B] = weight of concrete central (in ton) B2 = weight of transmixer (in ton) B3 = weight of pump (in ton) T = G x h = working days per year x working hours per day This basic relation gives an ideational approach instead of numerical approach. Internal and external factors and the quality of workers and machines should increase in order to increase the productivity of plant. The relation given above shows that internal and external factors are more important than the quality of workers and machines.