Ahşap testere talaşlı alçı kompozitler /
Yazar: FUNDA UZER
Danışman: PROF. DR. NİHAT TOYDEMİR
İstanbul Teknik Üniversitesi / Fen Bilimleri Enstitüsü
Derece: Yüksek Lisans, 1996
Konu: Mimarlık = Architecture
Dizin: Alçı = Plaster ; Kompozit malzemeler = Composite materials ; Yapı malzemeleri = Building materials

Özet:
ÖZET Kompozit malzemelerin yapılarda yaygın olarak kullanılması endüstriyel yöntemlerle üretilmeye başlanmasıyla gerçekleşmiştir. Özellikle yirminci yüzyıldan itibaren teknoloji ve malzeme bilimindeki gelişmeler sonucunda kompozit malzemelerin önemi ve kullanım alanı daha da genişlemiştir. "Ahşap testere talaşlı alçı kompozitler" adım taşıyan bu tez yedi bölümden oluşmaktadır: Birinci bölüm, çalışmanın amacını, yöntemim, kapsamını, sınırlarını ve deneysel çalışmalar sonucunda elde edilen sonuçlan içermektedir. İkinci bölümde, genel olarak, kompozit yapı malzemeleri, bu malzemelerin tasarım ve üretim esasları, sınıflandırılması, özellikleri ve kompozit yapı bileşenleri ele alınmıştır. Üçüncü bölüm, bu çalışmada bağlayıcı madde olarak kullanılan alçı ve üretimi hakkında verilen bilgileri içermektedir. Dördüncü bölümde ahşap testere talaşlı alçı kompozit malzemeyi oluşturan ana maddeler ele alınmıştır. Beşinci bölümde, alçıya değişik oranlarda ahşap testere talaşı katılması suretiyle oluşturulan ahşap testere talaşlı alçı kompozit malzemenin fiziksel ve mekanik özellikleri yapılan ön deneylerle araştırılmıştır. Altına bölüm, bu çalışmanın gerçekleştirilmesi için yapılan fiziksel ve mekanik deneyleri ve deney sonuçlarını içermektedir. Yedinci bölümde yapılan deney sonuçlarına bağlı olarak, alçıya katlan ahşap testere talaşı oranının kompozit malzemenin fiziksel ve mekanik dayanımlarına olan etkileri ve etkinlik dereceleri irdelenmektedir. Elde edilen bulgulara göre, sözkonusu kompozit malzemenin bileşimindeki talaş oranı arttıkça malzemenin ısı tutuculuk özelliği artmakta ve malzeme hafiflemektedir. Fakat buna karşın kompozit malzemenin çekme ve basınç mukavemetleri ve buhar difiizyon direnci azalmaktadır. XIV

Abstract:
SUMMARY The wide spread usage of composite materials in structures was realized after being manifactured by industrial methods. Especially since the twentieth century the importance and usage areas of composite materials have been developed more as a result of improvements in the technology and materials are especially very important for the modern architecture. The composite materials are used for the solution of structural problems such as heat, noise and humid as well as in the construction of section elements that can solve physical, mechanic and technologic problems of which structures may have. But it should be kept in mind that the composite materials are generally used for the heat isolation. The composite materials that have very wide usage areas in the developed countries are recently known in Turkey. As there are not many investigetions for the composite materials in the sufficient level, this thesis called "plaster composites with wooden saw shaving"becomes more important. This thesis consists of seven sections: The first section includes the aim, method, content and limits of the study, and results obtained as a result of experimental studies. This study has two purposes. The first purpose is to investigate how and how much the wooden saw shaving rate added to the plaster and additional drive retarding matter effect the physical and mechanical qualities of plaster composite material with wooden saw shaving, the second purpose is to investigate where and how the plaster material with wooden saw shaving that has the necessary physical and mechanical performance will be used in a structure. In the second section, generally the importance of composite materials, design and production principles of composite materials, classification of composite materials, peculiarities of composite materials and composite building elements are discussed. When meeting the sheltering needs of people, the importance of reducing the environment and air pollution, energy saving for the rational usage of energy reserves that continuously decrease and can not be renewed, increasing the beneficial areas of buildings that are constructed on the lands becoming more important as the urbanization has increased and composite materials to solve the important structural problems occur. For these reasons today usage of composite materials and investigation of composite building elements are very important subjects. XVThe composite materials are made by people. They occur physical mixture or composition of two or more materials. This mixture or composition is three dimensional. Peculiarity which is provided in the composite material must not be in elements which are occured the composite material. It is possible to divide the composite materials in to three groups; binder substance composites, fibre equipped composites and laminated composites. Materials such as cement binder with light aggregate composites, plaster binder with light aggregate composites, asphalt binder composites, rigid foamed composites and cement binder with heavy aggregate are binder substance composites, cement binder composites, polymer binder composites, asphalt binder composites and plaster binder composites are fibre equipped composites, laminated wood composites, laminated plastic composites, laminated glass composites, laminated metal composites and sandwich composites are laminated composites. Peculiarities such as sufficient mechanic resistance, impermeability, high non- flammability, rigidity, plaster conservation, non- putrefaction, inodorousity and cheapness are requested for composite materials. But it is impossible to collect all of these peculiarities in one material. The composite materials are high performanced materials that are used widely in modem architecture. They are generally used in heat, noise and humid isolation and used in construction as wall, floor and roof elements. The material proposed in this investigation is a composite material with plaster binder wooden saw shavings. The main substances which constitute the plaster composite with wooden saw shaving are discussed in the third section. These main substances are plaster and wooden saw shaving. The rawmaterial of the plaster is gypsum. The gypsum is a sedimentary rock consists of gypsum minerals. There exist 79. 1 % calcium sulphate and 20.9 % water in the composition. Gypsum is rarely in the pure situation. Generally it includes clay, silica and iron compounds in vast amounts. When it is pure its colour is white. But when it includes foreign matters its colour may be grey, brown or pink. Gypsum is a half light permeable or it is transparent. Plaster is a structure (construction) material of which formula is CaS04.2H20, obtained by heating gypsum, evaporating 75% of the crystal water in the structure and grinding it, and it gains binding peculiarity again by being harden when mixed with water. This situation is inconvenient for treatment procedures.Plaster has a high heat conservation, resistance to flame and humidity and noise arrangement peculiarity. In the fourth section it was investigated whether the plaster used in this study conforms to TS 370. Normal consistency determination was made. Firstly 200 gr. plaster was weighed. It was put in a metal container. 100 gr. water was added to plaster in metal container and mixed for two minutes. Then this mixture was placed in to special device without waiting and space of mixture was flatted. After being got wet the borer of device, it was placed on surface of mixture. Its needle was adjusted on zero point, then the needle was got free. In tins situation borer fell to 34 mm. In next stage the same processes were repeated with 110 gr. water. In this XVIsituation borer fell to 29 mm. According to TS 370, if water which is needed for mixture is used, the borer will fall to 28-32 mm. So the result of experiments done shown that, water which is as much as 55% of the quantity of plaster used must be used. Later physical and mechanical peculiarities of the plaster were determined. And then the physical peculiarities of wooden saw shavings were determined. In the fifth section, the physical and mechanical peculiarities of plaster composite material with wooden saw shavings obtained by adding wooden saw shavings to the plaster in various rates are investigated as a result of pre-experiments.The pre- experiments were earned out for purpose of determining the experiment conditions and possibilities and providing more correct experiment results. In order to perform the experiments, shapes and dimensions of experiment samples were decided first. Then experiment samples were produced. The produced samples were dried until they become fix weighted and waited for 28 days. Firstly unit weight experiments were earned out on the experiment samples. According to the results of these experiments, unit weight values decreased from the second degree depending on a parabolic curve when the shavings rate added to the plaster was increased. Then ultravoice experiments were performed. By the results of the ultravoice experiments, the elasticity module (E) decreased when the shavings rate increased. After the physical peculiarities were determined, the mechanical resistances of experiment samples were fixed. According to the results of bending and pressure experiments, it was determine that bending and pressure resistances decreased as a parabol quality when the shavings rate added to the plaster was increased. It was determined as a result of pre-experiments that the rate of wooden saw shavings added to plaster effect the physical and mechanical resistances of composite material greatly. The sixth section includes the physical and mechanical experiments performed to realize this study. 100 unit weight, 100 ultravoice, 40 water suction, 100 bending, and 200 pressure experiments were performed on almost 100 prismatic samples produced for this purpose. Besides 9 steam permeability coefficient experiments were carried out on 9 circular samples. Results and graphics related to these experiments are given in this section. Experiments were carried out according to the principles accepted at the pre- experiments. Results obtained as a result of pre-experiments established the data for the main experiments. Experiment samples were produced, dried and waited for 28 days as in the pre-experiments. Firstly unit weight, ultravoice and water suction experiments were performed in the main experiments to determine the physical peculiarities, and bending, pressure, and steam permeability coefficient experiments for mechanical resistance. One of the important physical peculiarities of the materials is unit weight. Unit weight is the unit volume weight with material vacuum. The unit weight of material is calculated with methods which are known in physics. For unit weight experiments, firstly weights of all samples produced are weighed by means of xvusensitive balance. After taking samples from mould, their volumes are calculated by multiplying their weight in normal laboratory conditions by their dimensions. The unit weight of the sample is calculated by dividing weight by volume and the arithmetic mean of unit weights is calculated for every wooden saw shaving rate. Then the graphic which shows the change of the unit weight is drawn according to the change of saw shaving / plaster rate. In this experimental study, after calculating the unit weight values, the ultravoice experiments of all the samples are done. So the forehead parts of the samples are flattened and these parts are greased for filling vacuums. After all these steps ultravoice measures of the samples are done. For static elasticity module calculation, firstly velocity is calculated by Velocity = Length / Time formula. Next static V2 A elasticity modules (E) are calculated as N/m2 by E = formula and the S arithmetic mean of static elasticity modules is calculated for every wooden saw shaving rate. Then the graphic which shows the change of the static elasticity module is drawn according to the change of saw shaving / plaster rate. After the ultravoice experiments water suction experiments are done. 4 water suction experiments are done for every type. So forty water suction experiments are done totally. In this experiment the samples are sunk into water until 1/4 of their height firstly, 2 hours later until 1/2 of their height, 2 hours later until 3/4 of their height and 2 hours later completely. So they are waited into water for 24 hours. Then weights in water and water satiated weights of the forty samples whose dry weights are known are calculated. The water quantity which is sucked by samples, volume of the samples, samples' water suction and unit weights of the samples are found with these datas. In next step the arithmetic mean of water suction quantiies is found for every wooden saw shaving rate. Then the graphic which shows the change of the water suction quantity is drawn according to the change of saw shaving / plaster rate. After physical experiments firstly bending resistance experiments are done for finding mechanic resistances of samples. In these experiments fulcrum distance of bending press is 10.0 cm. and a caoutchouc layer is placed on prismatic samples. Then force is started to apply. In bending experiments, load is applied in the middle of the distance. So bending resistance values are calculated according to breaking forces in experiments done. The bending resistance values are calculated as N/mm2 3 P 1 by a, = r formula and the arithmetic mean of bending resistance values is J e 2bh2 calculated for every wooden saw shaving rate. Then the graphic which shows the change of bending resistance is drawn according to the change of saw shaving/plaster rate. In experimental study, pressure resistance experiments are done on every samples which are seperated two groups according to the result of bending experiments. The pressure force is applied after putting a 4.0/4.0 cm. brass layer on the prismatic sample and calculation of the pressure area is found by multiplying width of the xvuisamples by 4 cm. dimension of brass layer. So pressure resistance values are P calculated as N/mm2 by ob = - formula according to the breaking loads in A experiments done and the arithmetic mean of pressure values is calculated for every wooden saw shaving rate. Then the graphic which shows the change of pressure resistance is drawn according to the change of saw shaving/plaster rate. For the steam permeability coefficients experiments, 2 circular samples with 6.50 cm. diameter and 1.00-1.50 cm. thickness are produced for every wooden saw shaving rate. Then circular samples produced are flattened. Their diameters and thicknesses are measured. Next styropors with 2 cm. thickness are cut and placed at the bottom of plastic containers in which the circular samples will be placed. Some calcium clorür is put on these styropors for sucking humidity. Then the circular samples are placed on plastic containers. The paraffin is rubbed on the parts which touch the container and forehead parte of the samples. The experiment samples which are occured on this way are balanced once in 24 hours. The balancing is repeated until the difference between last measurement and previous measurement is constant. After the steam permeability coefficients experiments the calculation of steam diffusion resistance values is done. Then the graphic which shows the change of steam diffusion resistance value is drawn according to the change of saw shaving/plaster rate. Values obtained as a result of unit weight ultravoice and water suction experiments gave general information about the physical peculiarities of composite material, and values obtained as a result of bending and pressure experiments about mechanical resistances of composite material. Humid regulation effect of the said material was determined as a result of steam permeability coefficient experiment. Depending on the experiment results performed in the seventh section, the effects and effectiveness degrees of wooden saw shavings rate added to the plaster to the physical and mechanical resistances of composite material were examined. According to the obtained findings, increment of the shavings rate added to plaster provides decrement for the physical and mechanical resistances as a second degree curve quality. However increment of the shavings rate added to plaster provides increment to the heat conservation peculiarity as a second degree curve quality. In other words, as the shavings rate in the compound of said composite material is increased, the heat conservative peculiarity of the material increases and material becomes light. But the pulling and pressure resistances of the material and steam diffusion resistance of it decrease. According to these results it should be obtained on optimum solution by developing the peculiarities of the material by considering its usage purpose and usage place. Because it is impossible for a composite material to have all the requested peculiarities. The composite material has lots of general peculiarities. ît has enough pressure resistance. That is why it is suitable for usage in floors and roofs. In case the resistance is not enough a preservative layer must be placed on the composite material. But this material can not withstand pulling stretch because of its low sixbending resistance. Therefore it must not be used in the places which are to be bent in constructions like in console tables. Due to its structure with vacuum it has low steam permeability resistance. The peculiarity provide to this material high respiration capacity in buildings. However, it is unsuitable to be used in wet spaces. Otherwise the condensation which will occur on surface of material may cause moldiness problems. Plaster composite with wooden saw shaving material provides a low heat conductivity value by means of micro and macro vacuum in its structure. This peculiarity ensures the material opportunity of being used as a heat isolation material. It could also be used in wall, floor and roof as a heat isolation material. But it should be protected from point load, diffused load and water with rigid layers which have definite thickness. This material is carried, applied and shaped easily, because it is a light material. It is durable against fire and flame. When it bums, it never gives off poison gas. The results of physical and mechanical experiments done shown that the composite material has high performances. Besides this seventh last section includes evaluation of the obtained results according to the hypothesis, suggestions and other results as a result of investigation. XX