Investigation of the quality of concrete used in prefabricated buildings and recommendation of new concrete material coefficient

The main aim of this study is to determine the quality of prefabricated concrete. Concrete compressive strength is the most important parameter of the concrete quality. The results of 7 and 28 days compressive strengths of concrete are used. The data of the study are collected from prefabricated building companies in Ankara, Konya, Aksaray and Malatya. The data belonging to C20, C25, C30, C35, C40, C45 and C50 concrete classes is separated and analyzed for each firms. The average values, standard deviations and coefficient of variations are calculated. To define the best fit distribution for compressive strength of concrete; The Chi-square and Kolmogorov-Smirnov tests are performed by using a commercial computer program called Easyfit. An uncertainty analysis are conducted based on the concrete compressive strength data and finally, the value of 1.35 are purposed as the new concrete material coefficient for prefabricated buildings.