STUDY ON THE WATER VAPOR PERMEABILITY THROUGH GEOTEXTILES USED IN REPAIR / STABILIZING ROADS

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1 STUDY ON THE WATER VAPOR PERMEABILITY THROUGH GEOTEXTILES USED IN REPAIR / STABILIZING ROADS Dorin VLAD1, Alina-Mihaela COLDEA1, Anca-Mădălina IRIDON1 This paper presents an experimental researches regarding the influence of the raw material on the water vapor permeability through unconventional textile materials (geotextiles) used in repair / stabilizing roads. Moreover, sorption properties, including the ability to absorb water vapor, allows the realization of specific textile finishing and change physical properties during use, also can be established optimal storage conditions. For tests were used standard STAS Textiles. Determination of the water vapor permeability. We chose 10 different types of samples, according to raw material and thickness. KEY WORDS: geotextiles, water vapor permeability, polyester, polypropylene. ABSTRACT: 1. INTRODUCTION Geotextiles are permeable fabrics which, when used in association with soil, have the ability to separate, filter, reinforce, protect, or drain. Typically made from polypropylene or polyester, geotextile fabrics come in three basic forms: woven (resembling mail bag sacking), needle punched (resembling felt), or heat bonded (resembling ironed felt) [18]. Benefits from the use of geotextiles are [1, 18]: ă constructionă worksă areăexecutedă moreăsimplified,ă productivity increases; ă goodă economyă foră stonyă materials,ă wood,ă bitumen, fuels, because thickness of geotextiles reduce or replacement of rocky material layers up to cm; ătheătotalămassăofăhandled and transported materials decreases (up to 1000-fold); In general, the vast majority of geotextiles are made from polypropylene or polyester formed into fabrics as follows [19, 20]: woven monofilament (figure 1a), calendered woven monofilament (figure 1b), woven multifilament (figure 1c), woven staple (figure 1d), nonwoven continuous filament needlepunched (figure 1e), nonwoven resin bonded (figure 1f), woven slit-film multifilament, nonwoven continuous filament heat bonded, nonwoven staple needle-punched, other woven and nonwoven combinations, knitted. The four main polymer families most widely used as the raw material for geotextiles are: Polyester Polyamide Polypropylene Polyethylene 102 LucianăBlaga ăuniversityăofăsibiu,ăemilăciorană street, 4, Sibiu, Romania, dorin.vlad@ulbsibiu.ro 1 Figure 1. Basics raw fibers and structure for geotextiles materials The oldest of these is polyethylene, which was discovered in 1931 in the research laboratories of the ICI. Another group of polymers with a long production history is the polyamide family, the first of which was discovered in 1935.The next oldest of the four main polymer families relevant to geotextile manufacture is polyester which was first

2 announced in 1941.The most recent polymer family relevant to geotextiles to be developed was polypropylene, which was discovered in The comparative properties of these four polymer are shown in very general items in the table 1 [20, 21]. Table 1. Comparative properties of the polymers used to obtain geotextiles beaching or as mattress structures. They can even easily be placed under water. 2. SAMPLES For this paper were used polypropylene fibers for GEOSIN samples (figure 2) and polyester fibers for TERASIN NS samples (figure 3), with following properties: Figure 2. GEOSIN sample H: High; M: Medium; L: Low Because of this wide variety, they can be applied in at least five different ways [22]: 1.Separation - Geotextiles will prevent two soil layers of different particle sizes from mixing with each other, as is illustrated the image below. 2.Drainage - Geotextiles will efficiently collect superfluous water from structures, such as rainwater or surplus water, from the soil and discharge it. 3.Filtration - Geotextiles are an ideal interface for reverse filtration in the soil adjacent to the geotextile. In all soils water allows fine particles to be moved. Part of these particles will be halted at the filter interface; some will be halted within the filter itself while the rest will pass into the drain. The complex needle-punched structure of the geotextile enables the retention of fine particles without reducing the permeability of the drain. 4. Reinforcement - Heavy geotextiles can be used to reinforce earth structures by means of fill materials. Thanks to their high soil fabric friction coefficient and high tensile strength, they are an ideal reinforcement solution. 5. Protection - Geotextiles are an ideal protection from erosion of earth embankments by wave action, currents or repeated drawdown. A layer of geotextiles can be placed so as to prevent leaching of fine material. They can be used for rock Figure 3. TERASIN NS sample Geosin geotextiles are obtained by mechanically strengthening of mixed fibres, made from original polypropylene fibres of high tenacity. Are used for a very wide application, as reinforcement layers and reinforcing of the slope (for the variants with a superior mass), drainage for all types, separation layers, filters and in particular the covering of waste dumps of ash from thermal power plants, where is needed of a small diameter and a high permeability filter [3, 4]. NS Terasin geotextiles are obtained by mechanically strengthening fibrous of mixed fibres, made from polyester. As applications we can mention for both type of samples: road rehabilitation, unpaved roads, foundations and mechanical protection for pipelines, foundations for pillars, dikes for flood protection, embankment and protect banks, stabilization underground, ponds, pools, biotopes, swimming pools, sandy areas, playgrounds, alley access garages, courtyards. In the figures bellow can see the main use for this two types of geotextiles [23]: 103

3 Figures 4. Railways applications standard atmosphere, after which it reweighed (weight m2). Figures 5. Civil applications and gardens Figure 8. Assembly glass+water+sample Is calculated the vapor permeability after 24 h and 48 h as a percentage [%] by using the relation 1 and 2. Figures 6. Basement drainage applications m1 = initial weight of assembly: glass + water + sample. m2 = weight of assembly: glass + water + sample after 24h. m3 = weight of assembly: glass + water + sample after 48h. S [m2] evaporation surface; The diameter of the glass mouth: 80mm => r = 40mm Surface:ăSă=ăπr2 = 3,14 x (40mm)2 = 5,024 mm2 4. RESULTS AND CONCLUSION Figure 7. Roads application 3. METHOD AND PROCEDURE In the table 2 and 3 are shown the results according to raw material, thickness and period of test (24h and 48h) Table 2. The values of water vapor permeability for the same thickness, but different raw material. To assess the vapor diffusion transfer we used as direct indicators, vapor permeability Pv[g] and Pv [%]. Measurements are made according to STAS Textiles. Determination of the permeability to water vapor - modified. According to this method, in a Herzfeld glass (1) was placed 75 ml of distilled water and the mouth of the glass is covered with the analyzed sample (3) and fixed with a ring (2). The assembly of glass, water and fabric (weight m1) was weighed, then kept for 24 hours in 104

4 Table 3. Values of vapor permeability, after 24h and 48h TERASIN NS 150 and the lowest, for the sample TERASIN 600 NS Table 3. Figure 9. The histogram of vapor permeability for TERASIN NS samples, after 24h and 48h From 24 to 48 hours, vapor permeability values increased by a percentage, between 41-52%, figures 9 and 10. The water vapor permeability is inversely proportional to the thickness (increases with decreasing thickness) in both types of samples Table 3, figures 9 and 10. For the same thickness but different raw material, we have higher values by 0.78% and 0.22% for samples of polypropylene (GEOSIN) Table REFERENCES Figure 10. The histogram of vapor permeability for GEOSIN samples, after 24h and 48h Analyzing the obtained results is observed that: 1. Loretta Batali Geotextile, CURS ANUL II, MASTERăINGINERIEăGEOTEHNIC 2. Dorin VLAD Metrologieăînătextileă piel rieă 1 ă laboratory notes, Sibiu, hp, Access date: august sin.php, Access date: September hp, Access date: august sin.php, Access date: September Access date: September Apetrei Dimitrie-Lucian, Hritcan MihaitaMarian Geotextileă șiă utilizareaă loră prezentare The highest value of vapor permeability after 24 hours was registered in the case of sample 105

5 PowerPoint,ă Universitateaă Tehnic ă Gheorgheă Asachi ădinăiaşi 9. F râm,ă Danielaă - Confortulă şiă funcțiileă produseloră textileă şiă dină piele,ă Edituraă Performantica,ăIași F râm,ă Danielaă - Confortulă şiă funcțiileă produseloră textileă şiă dină piele,ă Îndrumară deă laborator,ăedituraăperformantica,ăiașiă F râm,ă Danielaă - Confort si performanta in sport, Ed. Performantica, Iasi Grebennikov, S.F.; Kynin, A.T. Water vapor sorption mechanism and hygroscopicity of textile materials, Fibre Chemistry, vol.35, nr.5, e2, july McCullough, E.A.; Kwon, M.; Shim, H. - A comparison of standard methods for measuring water vapor permeability of fabrics, Measurement and Textile Technology 2003, 14, rii:ăaugustă SR EN ISO 15496: Materiale textile. M surareaă permeabilit țiiă laă vaporiiă deă ap ă aă materialelorătextileăînăscopulăcontroluluiăcalit ții. 15. Mazadul Hasan Sheshir Nonwovens, Southeast University, Department of Textile Engineering, I/A 251,252 Tejgaon Dhaka, Bangladesh 16. S. Rajesh Kumar Nonwoven manufacturing needle punching technique. 17. Manualul Inginerului Textilist, Editura AGIR,ăBucurești,ă Access date: September Robert M. Koerner Designing with Geosynthetics, tiles.htm, Access date: September John N.W.M, Geotextiles, extiles-industry/faq/what-are-the-5-mainfunctions-of-geotextiles, Access date: September