Nazmi ŞENGÜN, Göhan EKİNCİOĞLU, Deniz AKBAY, Raşit ALTINDAĞ

SEDİMANTER KARBONATLI KAYAÇLARDA ÖRNEK BOYUTUNUN YOĞUN YÜK ALTINDA BÜKÜLME DAYANIMINA ETKİSİ

Eğilme dayanımı, doğal yapı taşlarının uygulama alanı seçiminde kullanılan önemli bir mekanik özelliktir. Ülkemizde doğal taşların eğilme dayanımları Avrupa Birliği'ne uygun olarak hazırlanan deney standartlarına göre belirlenmektedir. TS EN 12372 standardına göre doğal taşların eğilme dayanımı tayini için önerilen deney numunesi ölçüleri 50×50×300 mm'dir. Ancak binalarda yer ve duvar döşemesi uygulamalarında genellikle 20-30 mm kalınlığında plakalar kullanılmaktadır. Pratikte 50 mm kalınlığındaki plakaların çok nadir kullanılmasının yanında 50 mm kalınlığında test numunesi hazırlamak da zahmetli ve zaman alıcı bir işlemdir. Bu çalışmada, iki farklı boyutta hazırlanan deney numunelerinin kullanılması durumunda örnek boyutunun karbonatlı kayaçların eğilme dayanımlarını ne kadar etkilediği araştırılmıştır. Aynı kayaya ait farklı boyutlarda hazırlanan deney numunelerinden elde edilen eğilme dayanımı değerlerinin birbirine çok yakın olduğu görülmüştür. Ayrıca kaya numunesi üzerinde oluşan gerilme dağılımları ANSYS Workbench 2020 R1 ile analiz edilmiştir. Aynı yüke maruz kalan farklı boyutlarda hazırlanmış numunelerde gerilme dağılımlarının aynı bölgelerde meydana geldiği, yoğunlaştığı tespit edilmiştir.

THE EFFECT OF SAMPLE SIZE ON THE FLEXURAL STRENGTH OF SEDİMENTARY CARBONATE ROCKS UNDER CONCENTRATED LOAD

Flexural strength is an important mechanical property used in the selection of the application area of natural building stones. The flexural strength of natural stones in our country is determined according to the test standards prepared by the European Union. According to TS EN 12372, the recommended test sample dimensions for the determination of the flexural strength of natural stones are 50×50×300 mm. However, generally, 20-30 mm thick plates are used in flooring, cladding, and exterior applications in buildings. In practice, 50 mm thick plates are rarely used, as well as preparing 50 mm thick test samples is a laborious and time-consuming process. In this study, it has been investigated how much the sample size affects the flexural strength of sedimentary carbonate rocks when using test samples prepared in two different sizes. It has been observed that the flexural strength values obtained from the test samples prepared in different sizes of the same rock are very close to each other. Besides, the stress distributions formed on the rock sample were analyzed with ANSYS Workbench 2020 R1. It has been determined that the stress distributions in the samples prepared in different sizes, exposed to the same load, occur in the same regions, and concentrate.

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