Affiliation:
1. State University of Feira de Santana
Abstract
The dimensional instability of vegetable fibers due to hygroscopicity results in a gradual loss of adherence in cement based composites which, when in service, are submitted to a natural variation of humidity. Such an effect reduces the contribution of the fiber as a reinforcement and can cause the early rupture of the material. In this work, a treatment of the sisal fibers is performed with the applying of wetting-drying cycles in order to alter their crystalline structure and improve the dimensional stability of the fiber to withstand the variation of humidity: 6, 10, 20, 30 and 34 cycles were applied in order to evaluate the effect on the properties of fiber; a tensile test, the morphological characterization (MEV) and the evaluation of the chemical structure of fiber were carried out. The effect of the treatment on fiber-matrix behavior was evaluated using the pull-out test. Embedded lengths of 16, 20, 30, 40 and 44 mm were defined through a factorial design and used in the test. It is verified that the use of 10 wetting-drying cycles causes less damage to the tensile strength and the elastic modulus of the fiber and contributes to a better adherence with the matrix, with an increase of up to 23 % compared with the untreated fiber. The statistical analysis of the interaction effect between the studied factors, using 2K factorial design with central composite design, indicates that the number of cycles can be decreased when using a longer length of the embedded fiber.Keywords: wetting-drying cycles, pull out test, tensile strength..
Publisher
Trans Tech Publications, Ltd.
Subject
Mechanical Engineering,Mechanics of Materials,General Materials Science
Reference19 articles.
1. H.E. Gram. Natural fibre concrete roofing. In: NATURAL FIBRE REINFORCED CEMENT AND CONCRETE, V. 5, Anais… Edited by R.N. Swamy, Blackie and Son Ltd, London, 1988: 257-285.
2. H.E. Gram. Durability of natural fibers in concrete, Swedish cement and concrete research institute, Research Fo. 1: 83, Stockolm. 1983, 255p.
3. R.D. Toledo Filho, K. Ghavami, G.L. England and K. Scrinever. Development of vegetable fibre-mortar composites of improved durability. Cement And Concrete Composites. v. 25, n. 2, pp.185-196, (2003).
4. G.H.D. Tonoli, S.F. Santos, W.N. Santos and H. Savastano Jr. Thermal performance of sisal fiber-cement roofing tiles for rural constructions, Scientia Agricola. Piracicaba, v. 68, n. 1, pp.1-7, January/February (2011).
5. J. Fiorelli, R. Schmidt, C.Y. Kawabata, C.E.L. Oliveira, Savastano Jr and J.A. Rossignolo. Eficiência térmica de telhas onduladas de fibrocimento aplicadas em abrigos individuais para bezerros expostos ao sol e à sombra. Ciência Rural. Santa Maria, v. 42, n. 1, pp.64-7, (2012).
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