Universtiy of Maribor2016 Spring SemesterTechnical Textiles
Instructor: Zoran Stjepanovi
A research about technical textiles that used in civil engineering applicationsIntroductionTecnical textiles used in construction of buildings are called buildtech. Textile materials used in buildings for so many years. Utilization of these materials is increased with the development of synthetic fibers. Today, these materials are widely used in airports, stadiums, sports halls, exhibition halls and shows centers, military and industrial warehouses and also at a lot of different areas like these places. Technical textiles are one of the faster-growing sectors of the global textile industry. High-added-value textile structures are replaced with traditional technologies. The efficient use of energy, materials and resources continues to be the driver for the industrial, construction and building sectors. Civil engineering applications have a huge effect on improving of peoples life such as planning, building and infrastructure. Technical textiles and composites play a big role in the construction sector, providing filters, reinforcement materials, webbings etc. These are the areas with high growth potential particularly in where the construction industries are carefree. So textiles, polymers and composite materials using in civil engineering applications began to be common more and more. Because of the plenty of advantages, textile materials are the one of the most important part at constructions. Some of those advantages are lightweight, strength and resilience, and resistant to chemicals, sunlight, pollutants. Technical textiles using as both permanent and temporary applications. More visible area of tents, marquees and awnings which they also can be built with aesthetic concerns. Lately those kind of textile applications called textile architecture.
Using areas and advantagesBecause of the so many good properties, technical textiles can be used at these areas; concrete reinforcement, faade foundation systems, interior constructions, insulations, proofing materials, visual protection, protection against the sun, building safety, textile membranes for roof construction, hoardings and signages, scaffolding nets, awnings and canopies, tarpaulins, architectural membranes and roofing materials.Buildtech products have to be durable and especially resilient. Important quality criteria are high UV resistance, sturdiness, resistance to wind and weather and to be light-weight. In addition to these properties, textile materials also with fair price. However, to meet the achievements, textiles used in civil engineering applications also have to have the properties such as; air conditioning, noise prevention, tear-resistant, water and vapor impermeable, anti-slip ensures safe installation, non-allergenic, bacteria resistant and rot-proof. The average weight of the textile material used in a standard building; is abut 1/30 of the weight of brick, steel or concrete. Thus, it needs less reinforcement so the cost is reduced. Also, manufacturing of textile materials is more easy and taking less time than traditional construction materials.
Fibers used in buildtechTechnical textiles generally made from synthetic fibres. 22% of the fibre consumption in the world is for manufacturing of technical textiles[Table1]. The most common ones are; high-tenacity polyester, glass fiber and nylon. Because of the tensile properties, strength and cost polyester is used more than the others. Also nylon fiber used for membranes sometimes but this fiber is more expensive than polyester(more durable at the same time). Glass is an incombustible textile fibre and has high tenacity too. It has been used for fire-retardant applications and also is commonly used in insulation of buildings. Because of its properties and low cost, glass fibre is widely used in the manufacture of reinforcement for composites. Glass fibers fairly resistant for tensions and they also and reflect the some of sun's rays and this provides to the keep structures cold. Glass fibre applications can be between 2 layers of concrete(as an insulation material)[Figure 2]. Also fabrics from glass fiber generally manufactured as nonwovens. [Figure 3]Polyethylene and polypropylene have a density less than that of water, which allows them to float as ropes, nets and other similar applications. The availability, low cost and good resistance to acid and alkaline environments of polypropylene has greatly influenced its growth and substantial use in geotextile applications.Hemp fibres with a higher durability than traditional cellulose fibres are more suited for this kind of application, and therefore a lot of research was performed about the use of hemp fibres as reinforcement for building materials based on cement.Some applications of other fibers are, HDPE(high density polyetylen) used for when really high resistance wanted. To achieve heat and sound isolation, hollow fibers are starting to be using. Composites generally have a bright future in building and construction. Current applications of glass reinforced materials, include wall panels, septic tanks and sanitary fittings. To prevent cracking of concrete, plaster and other building materials glass, polypropylene and acrylic fibres and textiles are using. More innovative use is now being made of glass in bridge construction. In Japan, carbon fibre is attracting a lot of interest as a possible reinforcement for earthquake-prone buildings although price is still an important constraint upon its more widespread use.(Handbook of Technical Textiles)
Technologies used in buildtechTextiles in this field; they must be resistant to degradation.to deformation and degradation under load, wind, water, sunlight or acid rain to in the case of a long time exposure of these factors. Also they have to be reflect or pass the sunlight according to using area. The vast majority of these properties are obtained by coating the base fabric used with a variety of chemicals. Generally plain constructions are used at woven fabrics because of their low hairiness, warp knit fabrics because they are strong, nonwoven fabrics which are produced needling method preferred because they are cheap and light-weight. Coated fabrics for waterproofing (and also to protect base fabric against sunlight and climate change), and coated fabrics for fire resistant which they are mostly polyvinyl chloride (PVC), polytetrafluoroethylene (PTFE) or silicone coated fabrics. Another technique for buildtechs is laminated fabrics. Laminated fabrics are preferred formed by vinyl film coating on woven or knitted polyester and nylon fabrics. They are cheaper than coated fabric, but the tensile strength, flexural and abrasion resistance lower.Unlike conventional construction methods, there are different innovative requires in new buildings. To achieve these properties, both new fiber and fabric types are discovering. Such as, fiberglass used 3 axial fabric or using friction hybrid yarn knitted spacer fabrics. Warp knitted fabrics are used as buildtech especially when strength is important. Using of fibers such as glass fibers, Kevlar fibers, strength is further increased. Also with using 3 axial knitting machines and with glass fiber, some fabrics are produced and they provide heat insulation. [Figure 4]Also in building sector, with aesthetic and strength concerns, there are starting to produce spacer fabrics for heat and sound insulations. To reinforce to concrete, also there are some sandwich structures which spacer fabrics and concrete are combined together. [Figure 5]
Examples for buildtechs Textile architectureMost people have at one time or another spent the night in a tent and have benefited from the protection provided by its fabric, while at the same time enjoying the sensation of being separated from nature by nothing more than a thin shell. Textile forms of habitation have a long history going back to palaeolithic times and represent an archetypal form of building which has endured to the present day. Textiles are light, easy to convert or dismantle, and they provide protection against wind, ultra-violet rays and rain.More fabrics are being used in buildings to provide solar protection. By adding textiles in architecture of a building not only can the UV rays be kept at bay but also a shade can be provided. Energy efficiency has also increased the use of textiles. From production and fabrication to the installation of membrane systems a lot of energy can be saved than using conventional concrete structures. Textile also provide a way of letting natural light being harnessed in a building by using translucent materials, thereby saving electricity and being environment friendly.Today, the textiles used in stadiums, sport complexes and fairs etc. generally are membranes they they are resistant to light and water and at the same time they are breathable. Modern architecture has rediscovered the principle of the tent as an architectural form and taken its development further not just for temporary structures but also for permanent buildings. Advanced and durable fabrics enable large areas to be spanned, which has turned their use into a highly specialised sector within the construction industry.When the textile elements are no longer required they can be folded up and stored compactly in a cupboard. In addition the fabrics are machine washable.In general, membranes used in building and construction field, are formed at both sides of the composite coated textile surface.[Figure 6] Two basic units forming the membrane; It is ground fabric and coatings. Ground fabric usually used in synthetic fibers and ground fabric acts as a carrier layer which provides structure and strength necessary to lift the entire load on the structure.
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