بررسي تاثير مواد پوزولاني مختلف بر روي دوام بتن مسلح شده با الياف شيشه تحت سيكل هاي يخ و ذوب

چكيده انگليسي :

126 The Study of Different Pozzolanic Materials Effects on Durability of Glass Fiber Reinforced Concrete Subjected to Freeze and Thaw Cycles HamidReza Rafiei hr rafiei@cv iut ac ir June 2 2015 Department of Civil Engineering Isfahan University of Technology Isfahan 84156 83111 IranDegree M Sc Language FarsiSupervisor Dr Morteza Madhkhan madhkhan@cc iut ac ir Email address AbstractPhysical and mechanical properties of concrete on the one hand and ease of its production of on the otherhand has made the concrete to the most widely used building materials industry the tensile strength ofconcrete is very low strengthening and improving Besides properties of concrete is one of the mostimportant things that has been the interest of scientific communities One of the new materials that has beenallocated special place in Strength concrete is glass fiber In fact Glass Fiber Reinforced Concrete GFRC isa composite that by using of glass fiber resistant to alkaline environments in the concrete mixture theirflexural and tensile strengths will be increased High ductility strength and resistance to cracking are theother properties of this concrete In this research the effect of Microsilica Metakaolin and Nanosilica on the durability of glass fiberreinforced subjected to the freeze and thaw cycles was investigated The amount of Microsilica wasconsidered 10 and 15 Nanosilica 0 75 and 1 5 and Metakaolin 10 and 15 by weight of cement The samples were made by two methods of premix and spray In the production of premixed samples thefiber content was 1 5 and 2 5 percent by volumetric weight of GFRC and in the production of spraysamples the amount of fibers was considered 4 and 6 percent by volumetric weight of GFRC Afterconstruction and curing of the samples in accordance with code ASTM C666 B they have been subjected tothe freeze and thaw Cycles For comparing the performance of the mix designs under the freeze and thawcycles Compressive strength tests Flexural Toughness and Flexural strength tests and study of length andweight changes after ending of freeze and thaw Cycles were performed Also the content of water absorptionwas studied as other effective parameter on glass fiber reinforced concrete durability The results showed that adding glass fiber to concrete lead to a low increase on compressive strength andincrease significantly the modulus of rupture and ductility Also the addition of pozzolanic materialsincluding metakaolin and microsilica in all mixes and also nanosilica with the rate of 0 75 percent to sampleswith glass fiber cause to increase the compressive strength modulus of rupture and ductility of samples after28 days and 150 and 300 freeze and thaw cycles But with increasing the amount of nanosilica from 0 75 to1 5 compressive strength modulus of rupture and ductility of samples decrease at all ages of tests The addition of glass fiber and pozzolanic materials including metakaolin and microsilica in all mixesand also nanosilica with 0 75 percent reduces compressive and flexural strengths drop after freeze and thawcycles According to the obtained results of water absorption it was found that adding glass fiber to concreteincreases the water absorption But adding metakaolin and nanosilica and specially microsilica reducessignificantly the amount of water absorption of fiber samples

رفيعي، حميدرضا

بررسي تاثير مواد پوزولاني مختلف بر روي دوام بتن مسلح شده با الياف شيشه تحت سيكل هاي يخ و ذوب

بتن اليافي , GFRC , خصوصيات مكانيكي و دوام