engleski

Comparison of Different Methods for Tensile Strength Testing of Geotextiles

Geosynthetics are synthetic materials manufactured as fabrics, nets or films, used in all the areas of building and civil engineering, such as road construction, bridges, tunnels, environment protection constructions, building construction etc. First important geosynthetics were various types of textile fabrics, commonly known as geotextiles. Geotextiles can be manufactured as woven, knitted, and recently most often encountered nonwoven constructions, and are used for various purposes, such as separation, reinforcement, filtering and drainage. To be properly used for these purposes, geotextiles should possess adequate properties. Mechanical properties, strength primarily, are of key importance for reinforcement. Numerous methods and procedures have been developed for the purpose of testing tensile properties of geotextiles, most of them standardised and defined within branch, national and international standards. The paper presented describes nonwoven geotextiles strength testing, for the materials used in tunnel construction. Breaking strength is determined employing three testing methods:  testing method with wide bands, according to ISO 10319/1993 Five lengthwise samples and five widthwise ones are prepared. Width of the samples is 200 mm + 1 mm, while their length should match the distance between dynamometer clamps 100 mm. The clamps move apart at the speed of 20 mm/min.  trapezoid method for determining resistance to tearing, according to ISO 9073-4/1997 The testing is performed on five samples, both by length and by width. Sample dimensions are 75 + 1 mm x 150  2 mm. Using special patterns, isosceles trapezium is drawn on each testing sample and a cut of 15 mm is do ne on a shorter parallel side. The sample is fastened into the clamps by its sides that are not parallel, with the cut halfway between the clamps. Clamp distance is 25 + 1 mm, while the speed of moving clamps apart is 100 mm/min.  Grab-test, according to ASTM D 5034 Testing is done on 5 lengthwise and 5 widthwise samples, dimensions of 100 + 3 mm x 150 + 3 mm. In loading the testing samples, only 1/4 of the sample width is taken by the clamps. Testing is done on nonwoven textile sample, manufactured from polypropylenefibres, with the surface mass of 470 g/m2. Investigation is performed to determine correlation of the results obtained using the above methods, as well as to find out whether it is possible to substitute a method with another one and obtain acceptable results. The investigation is performed by comparing the variants using the Bartlett test and comparing arithmetic means using the F-test.

tensile strength; geotextiles

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