Ahşap Testere Talaşlı Çimento Kompozitin Fiziksel Ve Mekanik Özelliklerinin İncelenmesi

Abstract

Gûnûmûz yapı malzemelerinden beklenen özellikler, doğadaki enerji ve malzeme kaynaklarının azalması, insanların daha iyi ortam koşul larında yaşama İsteği dolayısıyla, artmıştır. Bu sebeplerden, yapı malzemesinde ışı, ses, su yalıtımı, dayanıklılık, kullanılabilirlik gibi Özelliklerin yanı sıra malzemenin hafifliği ve inceliği de bu nitelikler kadar önem kazanmıştır. Bu da kompozit malzeme üretimi ve kulla nımı gereğini ortaya koymaktadır. Kompozit malzemeler üzerine yapılan araştırmalar ve uygulamalar günümüz yapılarında kompozit malzemelerin kullanımının arttığını göstermektedir. Yıllardır inşaatların iki ana malzemesi olarak kulla nılan ahşap ve çimentonun fiziki karışımından elde edilen ahşap yonga talaşlı çimento kompozitin yapılarda kullanımı birçok yönden istenen sonuçları vermiştir ve uygulamaları halen devam etmektedir. Ahşaptan dolayı olabilecek çürüme ve böceklenmeleri çimentonun bazik yapısı ve neme direnç özelliği engellemektedir. Öte yandan çimentonun soğuk görünüşünü doğaya özgü sıcaklığıyla kapayan ah şap, aynı zamanda kompozit malzemeye yangına karşı dayanıklılığı arttırıcı bir özellik verebilmektedir. Bu nedenler uyumlu malzeme ikilisi ahşap ve çimentodan ahşap testere talaşı ve çimentonun oluş turacağı bir kompozit yapı malzemesinin mekanik ve fiziksel özellik leri üzerinde bir araştırma yapmanın yararlı ve gerekli olduğunu or taya koymaktadır. Ahşap testere talaşlı çimento kompozit yapı malzemesinin mekanik ve fiziksel özelliklerinin incelenmesinde deneysel çalışma ağırlıklı bir araştırma yapılarak bu araştırmada hipotetik-dedüktif yöntem kullanılmıştır. Ahşap testere talaşlı hafif beton kompozit üzerinde yapılan deney lerden elde edilen sonuçlar, ahşap testere talaşı oranı arttıkça kom- pozitte mekanik dayanımların azaldığını göstermektedir. Eğilme dayanımı değerlerinin doğrusal karakterde, basınç dayanım değer lerinin ikinci dereceden bir eğriye bağlı olarak azaldığı saptanmış tır. Ahşap testere talaşı oranı arttıkça kompozitin birim hacim ağır lık değerlerinin doğrusal olarak azaldığı, % su emme miktarlarının ve su buharı geçirimliliğinin arttığı, fakat yine de kompozitin dolu tuğlaya göre çok yüksek su buharı difüzyonu direnç faktörü değerlerine sahip olduğu tespit edilmiştir.

In this study, the effect of the ratio of cement binding sawdust, which is used in the production of composite construction material has been examined. Lessening of the energy and material resources in nature, the desire of people to live in better living conditions leads to the necessity of using a material which inheres more than one type of material. Not only the properties of material like heat, sound, water insulation, resistance, durability which is expected from a construction material but also the properties of lightness and slenderness have become important. In the construction of twentieth century, the elements used as nonload-carrying construction elements are expected to be light, slender, at least to carry its own weight, to be resistant to strokes. Additionally, as the material becomes slender and light, it becomes difficult to satisfy heat insulation properly. This fact shows the importance of the production and usage of composite material. The studies made on composite materials provides the usage of composite materials in various parts of constructions which are constructed nowadays. The examination of the physical and mechanical properties of composite materials which contain cement binding wooden sawdust was found to be useful and necessary because there is a similar material which is a composite material that contains cement binding wood shavings is being produced in Turkey. Wood and cement are always used as main construction materials In the constructions and it is still being used. Till the beginning of the 1920's wood and cement had been used seperately In the constructions. At those years there were some Investigations made on these materials In order to obtain a material which is composed of both of them. Some new physical and chemical properties were found at the end of the studies. At 1940 first panel with wooden fibers was produced by putting long wooden fibers into the cement. It has been seen that the use of wood shavings In the production of wood-cement composites is widespread. Today cement binding wood shaving panels are produced by mixing small amount of wood shavings into the cement. In Turkey, Turkish Standarts Enstltute (TSE) published TS5115 in 1985 in order to put standarts for the production of these panels. x Today's technology and needed material resources can easily be used in the production of this composite construction material. It has been seen that its production is more economical and easy for the purpose of heat insulation when compared to other alternative systems. This is a big advantage when the economy and energy resources of Turkey is taken into consideration. Because of these facts, the importance of the study on composite construction material is obvious. This composite material is the mixture of water, wood, cement and it is a modern construction material which has a big usage area in the constructions. The properties of wood like lightness, elasticity, workability and the properties of cement like resistancy to fire, water, moisture, insects give the composite good properties in order to be used as a construction material. In this study, three goals has been aimed by taking the above instructions into consideration: * The investigation of effect of sawdust ratio on the mechanical and physical properties of lightweight concrete composite material. * Production of a wall material, lightweight concrete composite material, whose mechanical strength is sufficient and who has an acceptable degree, of vapor diffisuion. * Experimental investigation of Portland cement, wooden sawdust which are needed for the production of this composite material and their production conditions. In the materalization of these three aims, hypothetic-deductive method has been used. There has been pre-experiments made to ascertain the limit of the wooden sawdust ratio in the specimen which would have been produced and to determine the conditions of experimental study. According to the results of the pre-experimental studies, an experiment program which is based on the change of wooden sawdust ratio has been programmed. The experiment program has been carried out successfully and good results for the production purposes have been obtained. xi A production method has been suggested according to the results obtained from experiments. Pre-experiment results provided good information about the agent, variation of agent, experiment conditions, specimen dimensions, specimen preparation conditions. The results obtained in this experimental study from 90 composite material specimens with 9 different wooden sawdust ratios and their mean values are given in tables. In the mean values, highest compression strength has been obtained in the specimens with %10 wooden sawdust ratio as 23 N/mm2, the least compression strength has been obtained in the specimens with %90 wooden sawdust ratio as 1 N/mm2. This situation shows that as the ratio of sawdust had been increased a decrease of %95.7 in the compression strength was observed. From the results obtained 90 bending experiments, mean values were calculated. The highest mean flexural strength has been obtained as 8 N/mm2 in the specimens with %10 sawdust ratio and the lowest mean flexural strength has been obtained in specimens with %90 wooden sawdust ratio as 0 N/mm2. These results show that as wooden sawdust ratio had been increased a %100 decrease in the flexural strength has been ascertained. The results obtained from static elasticity experiments have confirmed that as the wooden sawdust ratio increases mechanical strength of composite material decreases. In the specific volume calculation, as the wooden sawdust ratio had been increased, because of the increase in the ratio of material with decreased specific weight, specific volume values decreased linearly. In the 36 water absorbtion experiments, it has been ascertained that as the wooden sawdust ratio had been increased, the % water absorbtion of composite material naturally increased. The lowest mean water absorbtion value has, been obtained in the specimens with %10 wooden sawdust ratio as %18.1 and highest value has been obtained in the specimens with %90 wooden sawdust ratio as %77.9. in the water vapor diffusion experiments made on 9 different dimensioned specimens, the results obtained have showed that the specimen with %10 wooden sawdust ratio has diffused water vapor less than the other specimens. The u. values obtained has become -47.6520 for the specimens with %10 wooden sawdust ratio and -19.6692 for specimens with %90 wooden sawdust ratio. These values shows that cement composite construction material with wooden sawdust has less amount of water vapor diffusion xii capacity than the hallow brick as well as solid brick for every ratio of wooden sawdust. This experiment-based study has been composed of seven parts: In the first part, aim of study, method, scope and experimental study results have been explained. in the second part general properties of composite materials, conditions expected to be a composite material, classification, expected performances and composites used in heat insulation have been explained. In the third part, the main materials used in experimental studies has been examined. This part has been formed by the literature knowledge and experimental study on the cement and wooden sawdust production, their structure and various properties which are used in the formation of cement composite which contains wooden sawdust. In the fourth part the affect of variation of wooden sawdust ratio which is known to effect the physical and mechanical properties of lightweight concrete composite construction material has been examined by the pre-experiments. Fifth part contains the mechanical and physical experiments which have been made to materalize these studies. For this purpose 99 specimens has been used. On these specimens 90 specific weight experiment, 90 static elasticity experiment, 36 water absorbtion experiment, 90 bending experiment, 180 compression strength experiment, 9 vapor diffusion resistance factor experiment have been made. The results have been given in this part. Sixth part, is the part In which the effect of discussed wooden sawdust ratio changes on mechanical and physical properties of lightweight concrete composite construction material by the help of the obtained experiment results, has been commented on and appraised. According to the obtained results of experiments, as the added ratio of wooden sawdust into the cement had been increased, the mechanical strength of composite construction material decreased. The ascertained decrease In mechanical strength properties are: * Linear decrease in flexural strength. xiii * A decrease in compression strength and static elasticity modulus in the form of a second degree curve. Same situation has been ascertained in the specific volume values. As the amount of wooden sawdust ratio put into the cement had been increased water absorbtion and vapor diffusion decreased. Seventh part is the last part of this investigation, it contains the results obtained at the end of the study and the effect of wooden sawdust ratio whose effectiveness on the physical and mechanical properties of concrete composite construction material on the production of lightweight concrete composite construction material has been ascertained.