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چكيده انگليسي :

108 Degree M Sc Language Farsi Dr M R Eftekhar eft @cc iut ac ir Abstract Nowadays the application of fibrous concrete because of its advantages has been widely used Among these benefits high energy absorption improvement in the non linear behavior of concrete and prevent the development of shrinkage cracks can be named On the other hand reinforcing the concrete with fibers is one of the ways to repair the flexural and tensile performance which due to fibers brittle mixture show elastic performance To date the different fibers have been used in concrete Such as glass plastics steel fibers can be named Although artificial fibers have been resulted acceptable solutions for strenghth parameters and plasticity behavior but because of disadvantages such the difficulty of production expensivity environmental effects etc limited in use are consistent the researchers are now investigating the use of natural fibers in concrete and various parameters related to the use of these fibers in concrete have been investigated The natural fibers are mainly cellulosice based that in the alkaline environment will not only reduce resistance but also have increased resistance Most studies on the use of natural fibers in the fiber cement panels is limited Therefore due to the growing consumption of artificial fibers in concrete according to the proper characteristics of natural fibers within the textile industry goods and compatible with the environment and the one hand increasing price of petroleum as a raw material for artificial fibers on the other hand also announced 2009 as the year of natural fibers of the United Nations the importance of research into natural fiber is double the use of Leafiran plant fibers from the leaves Louis australis used in the concrete mixture was evaluated in this study The fibers extracted by Mortazavi in the Faculty of Textile at Isfahan University of Technologyfor the first time In this study polypropylene fibers and Leafiran fibers were used separately in three percent of 0 3 0 5 and 0 7 with a length of 12 mm and changes in compressive strength tensile strength flexural strength water absorption were reviewed Before reviewing the mechanical strength parameters of fiberous concrete was observed that the addition of fibers to concrete reduce the effictivness of concrete so by adding lubricant to the mixture desire slump had been yielded Adding polypropylene fibers and Leafiran to the concrete mixture reduces the concrete compressive strength but fibers increases tensile and flexural strength Reduction in compressive strength due to addition of fibers in different percentages Leafiran is about 4 percent less than the same percentage of polypropylene fibers and also leafiran fibers polypropylene fibers Leafiran percent increase compared to the tensile strength and flexural result has more In the next stage of the research in order to optimize the Leafiran fiber length the lengths of 40 and 60 mm in the concrete used and better results were obtained In the samples containing fibers of polypropylene fibers to increase the percentage of water absorption of concrete dropped if this trend was reversed in the case of Leafiran fiber that because Leafiran is hydrophilic fiber Keywords fibrous concrete Leafiran fibers polypropylene fibers tensile strength compressive strength bending strength mortar concrete water absorption fibers Isfahan University of Technology Civil Engineering Department

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ارزيابي كاربرد الياف گياه لويي در مخلوط بتن

بتن اليافي , الياف ليفيران , الياف پلي پروپلين , مقاومت كششي , مقاومت فشاري , مقاومت خمشي ملات , جذب آب بتن اليافي