B.ahmet YAŞAR, Mehmet Metin KOSE, Sila AVĞIN, Hüseyin TEMİZ

Düşük Dayanımlı Betonların Elastisite Modülünün Bulunması

Bu çalışma, düşük mukavemetli betonun esneklik modülünü deneysel olarak belirlemeyi ve yeni elastisite modülü denklemlerini önermeyi amaçlamaktadır. Elastisite modülü ile ilgili çalışmalar genellikle normal ve yüksek dayanımlı beton numuneleri için gerçekleştirilmiştir. Elastisite modülü, statik ve dinamik elastisite modülü olarak belirlenebilir. Bu çalışmada 64 beton test örneği hazırlanmıştır. Gerilme-birim şekil değiştirme çerçevesi üzerine 38 numune yerleştirilmiş ve statik elastisite modülünü belirlemek için basınç testine tabi tutulmuştur. Karakteristik beton basınç dayanımlarının %40, %45 ve%50'si TS-500, ACI 318-11 ve CEB 2004'e göre düşük mukavemetli betonun statik elastisite modülünü belirlemek için gerilim-gerinim eğrisinde ikinci bir nokta olarak kullanılmıştır. Statik elastisite modülü değerleri standart denklemleri ile karşılaştırılmış ve üç standardın düşük dayanımlı beton için daha yüksek esneklik modülü değerleri verdiği görülmüştür. 26 beton numunesinin dinamik elastisite modülleri ultrasonik test cihazı kullanılarak belirlenmiştir. Dinamik elastisite modülü değerleri Hermit fonksiyonu ile karşılaştırılmıştır. Hermit fonksiyonunun daha yüksek elastisite modülü değerleri verdiği gözlenmiştir. Bu nedenle, yapılan deney sonuçlarına göre düşük dayanımlı betonun statik ve dinamik elastisite modülü için regresyon analizi kullanılarak yeni denklemler, önerilmiştir.

Anahtar Kelimeler:

Düşük dayanımlı beton, Statik elastisite modülü, Dinamik elastisite modülü

Determination of Elasticity Modulus For Low Strength Concrete

This study aims to experimentally determine the elasticity modulus of low strength concrete and propose new elasticity modulus equations. Studies on elasticity modulus have been generally carried out for normal and high strength concrete samples. The elasticity modulus can be determined as static and dynamic elasticity modulus. 64 concrete test samples were prepared in this study. 38 samples were placed on the stress-strain frame and subjected to the compression test to determine static elasticity modulus. 40%, 45% and 50% of the characteristic concrete compressive strengths were used as a second point on the stress-strain curve to determine the static elasticity modulus of low strength concrete according to TS 500, ACI 318-11 and CEB 2004, respectively. Static elasticity modulus values were compared with three code equations and it was observed that three codes yield higher elasticity modulus values for low strength concrete. Dynamic elasticity modules of 26 concrete samples were determined using an ultrasonic test device. Dynamic elasticity modulus values were compared with Hermit function. It was observed that Hermit function also gives higher elasticity modulus values. Therefore, new equations for static and dynamic elasticity modulus of low strength concrete were proposed based on the experiment results using regression analysis.

Keywords:

Low strength concrete, Static elasticity modulus, Dynamic elasticity modulus,

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