Sedir Ağacının (Cedrus libani) Farklı Kısımlarından Üretilmiş Alçı Esaslı Levhaların Özellikleri. 1. Bölüm. Fiziksel ve Mekanik Özellikler

Öz

Bu çalışmada, odun ilavesinin, alçı esaslı levhalarda su alma (WA) ve kalınlığına şişme (TS) özelliğini azaltıcı etki gösterdiği bulunmuştur. En düşük su alma oranı %41,56 ile sedir kabuk/ibre karışımından (KaI3; 3:2, ağırlık: ağırlık) üretilmiş levhalarda gözlemlenmiştir. Sadece kabuk-alçı (SKa6) ve kozalak-alçı (SKo6) ve ibre-alçı (SI6) karışımından üretilmiş deneme levhalarının kalınlığına şişme oranları sırasıyla %33,70, %21,70 ve %18,85, hesaplanmıştır. Ayrıca, yüzey sertlik (Shore D) değerleri genellikle levha karışımındaki odun oranı ile pozitif, fakat doğal yaşlandırma işlemine tutulmuş levhalarda ise negatif ilişkisi olduğu ve % -6.9 (SKa1) ile %-30.3 (SKa2) arasında azalmalar belirlenmiştir. Sedir odun/kozalak, (SKo); sedir odun/ibre (SI) ve sedir kozalak/ibre (KoI) karışımlarından üretilmiş levhaların yapışma direnç değerleri (IB), standart değer olan 0.28 N/mm2 den daha düşük hesaplanmıştır. En yüksek yapışma direnci 0.48 N/mm2 olarak 1:4 (ağırlık/ağırlık) oranında sedir odun/sedir kabuk (SKa5) örneğinde belirlenmiştir. En yüksek eğilme direnci ise (MOR) 1.32 N/mm2 olarak 4:1 (ağırlık/ağırlık) oranında sedir odun/sedir kabuk (SKa5) örneğinde belirlenmiştir. Bu mekanik değerler deneysel levha hazırlama aşamaları ile yakından ilişkili olduğu zira çok basamaklı proseslerde (ıslatma, taslak oluşturma, presleme ve kurutma), ilave edilen güçlendirme elamanlarının etkisini engelleyerek matris yapıda uygun direnç oluşumunu etkileyebilirler.

Anahtar Kelimeler

• Sedir odunu
• kozalak
• ibre
• alçı levha
• yapışma direnci
• MOR
• MOE.

Properties of Gypsum Boards Made with Cedrus Tree (Cedrus libani) Components. Part 1. Physical and Mechanical Properties

Abstract

In this study, it was found that the addition of wood had a reducing effect on water absorption (WA) and thickness swelling (TS) properties in gypsum-based boards. The lowest WA value of 41.56% was found sample prepared with cedrus’s bark/needle mixture (KaI3; 3:2 by weight). It has also been realized that experimental boards made only bark-gypsum (SKa6), cone-gypsum (SKo6) and needle-gypsum (SI6) proportions show Thickness Swelling (TS) values of 33.70%, 21.70% and 18.85%, respectively. However, the surface hardness (Shore D) has usually correlated with wood content but natural weathering negatively effects hardness that lowering from -6.9% (SKa1) to -30.3% (SKa2) in all typse experimental boards. It was found that panels produced with cedrus wood/cone (SKo); cedrus wood/needle (SI) and cedrus cone/needle (KoI) proportions have no higher values than standard Internal Bond (IB) value of 0.28 N/mm2. But the highest IB value of 0.48 N/mm2 was observed for a sample of SKa5 that produced with a ratio of 1:4 by cedrus wood/bark proportions (w/w). Moreover, the highest bending strength (MOR) values of 1.32 N/mm2 were calculated with SKa2 sample that produced with ratio of 4:1 by cedrus wood/bark proportions (w/w). These mechanical properties are probably related to experimental board manufacturing process, which consists of multi stage processing (slushing, soaking, formation, pressing and drying) may effect hindering reinforcement elements to develop the network matrix strength properly.

Keywords

• Cedrus wood
• cone
• needle
• gypsum board
• internal bond
• MOR
• MOE

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