Increasing Mechanical Strength of Ignimbrite Rocks

Abstract

Ignimbrite is a type of pyroclastic rock that is formed by the volcanic lava. With the explosion of the Nemrut crater in the city of Bitlis, the lava sprawling around it has cooled down. Because of these cooling, pyroclastic rocks, known as Ahlat stones (AS), were formed in the region. The compressive and bending strength of natural Ahlat stone is very low. In this study, the compressive and bending strength of natural Ahlat stone has been increased by the applications of drying oven curing and combined curing. Natural AS samples were cut into sizes of 150×150×150 mm for compressive test and of 100×100×400 mm for bending test. No cure was applied to some of the natural Ahlat stone samples brought from the quarry, which were selected as reference samples. 10 different cure types were applied to other natural Ahlat stones with the same characteristics as Reference Ahlat stone. These 10 different curing types included air curing, standard water curing, 4 drying oven curing types and 4 combined curing types. After curing, all samples were subjected to compressive and bending tests. Average compressive strength of the reference samples was found to be 9.8 MPa, and its bending strength was found to be 1.6 MPa. The highest average compressive strength of Ahlat stone was found to be 19.2 MPa after 3 days of drying oven curing at 200oC. The highest average bending strength of Ahlat stone was found to be 3.2 MPa after 3 days of drying oven curing at 200oC. The results of the study showed that the compressive and bending strength of the natural Ahlat stone can be increased to approximately 2 times after 3 days of drying oven curing at 200oC.

Keywords

• Ignimbrite rocks,Heat treatments,Drying oven curing,Combined curing,Compressive strength,Bending strength

İgnimbirit Kayaçlarının Mekanik Dayanımının Artırılması

Öz

İgnimbirit, volkanik lavlar tarafından oluşturulan piroklastik bir kayaç türüdür. Bitlis ilinde Nemrut kraterinin patlamasıyla etrafa yayılan lavlar soğumuştur. Bu soğuma nedeniyle bölgede Ahlat taşı (AT) olarak bilinen piroklastik kayaçlar oluşmuştur. Doğal Ahlat taşının basınç ve eğilme dayanımı çok düşüktür. Bu çalışmada, etüv kürü ve kombine kür uygulamalarıyla doğal Ahlat taşının basınç ve eğilme dayanımı arttırılmıştır. Doğal AT numuneleri basınç deneyi için 150×150×150 mm ve eğilme deneyi için 100×100×400 mm boyutlarında kesilmiştir. Taş ocağından getirilen ve referans örnekleri olarak seçilen doğal Ahlat taşı numunelerinin hiçbirine kür uygulanmamıştır. Referans Ahlat taşı ile aynı özelliklere sahip diğer doğal Ahlat taşlarına ise 10 farklı kür tipi uygulandı. Bu 10 farklı kür tipi; hava kürü, standart su kürü, 4 tip etüv kürü ve 4 tip kombine kürü içermektedir. Kür sonrası tüm numunelere basınç ve eğilme deneyi uygulandı. Referans numunelerinin ortalama basınç dayanımı 9,8 MPa ve ortalama eğilme dayanımı 1,6 MPa olarak bulundu. Ahlat taşının en yüksek ortalama basınç dayanımı, 200oC' de 3 günlük etüv küründen sonra 19,2 MPa olarak bulundu. Ahlat taşının en yüksek ortalama eğilme dayanımı, 200oC' de 3 günlük etüv küründen sonra 3,2 MPa olarak bulundu. Çalışma sonuçları, doğal Ahlat taşının basınç ve eğilme dayanımının, 200oC' de 3 günlük etüv küründen sonra yaklaşık iki katına çıkarılabileceğini gösterdi.

Anahtar Kelimeler

• İgnimbirit kayaç,Isıl işlemler,Etüv kürü,Kombine kür,Basınç dayanımı,Eğilme dayanımı

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