بررسي تاثير الياف و مواد پوزولاني بر روي خواص مكانيكي بتن مسلح شده با الياف شيشه

چكيده انگليسي :

143 The effect of fibers and pozzolanic materials on the mechanical properties of glass fiber reinforced concrete roozbeh katirai rzkatirai@yahoo com June 2 2015 Department of Civil Engineering Isfahan University of Technology Isfahan 84156 83111 Iran Degree M Sc language Farsi Supervisor Morteza madhkhan Email madhkhan@cc i ut ac irAbstractDamage and destruction of concrete depends on the formation of cracks and micro cracks By increasing ofloading micro cracks are connected together and create the cracks In order to solve this problem and create ahomogeneous situation in recent decades a number of thin filaments that spread throughout the volume ofconcrete is used which is called fibers Glass fibers are the most widely used fibers in concrete Glass fiberReinforced concrete is a composite material consisting of a mortar of hydraulic cement and fine aggregate sreinforced with glass fibers Using glass fibers in concrete improves the properties of concrete such asincreasing tensile strength flexural strength impact strength energy absorption improvement of nonlinearbehavior of concrete and ductility Since the properties of glass fiber reinforced concrete are in direct contactwith the conditions of glass fibers used in concrete the topices related to the performance of glass fiber duringthe time always have been considered by researchers During the time the factors such as alkaline environmentof concrete and cement hydration products damage the glass fibers cause the changes in the mechanicalproperties of glass fiber reinforced concrete In this study the alkali resistant glass fibers were used to reducethe effects of the alkaline environment of concrete and to prevent the damaging effects of cement hydration pozzolanic materials have been used with different percentages In this research to evaluate compressivestrength bending strength and toughness index of GFRC were performed with two methods of pre mixed andspray 15 mix designs with different percentages of glass fibers and pozzolanic materials micro silica metakaolin and nano silica in pre mixed method and 14 mix designs in spray method have been tested Bystuding the test results it can be concluded that the compressive strength of glass fiber reinforced concrete depends largely on the quality of the mortar It can be seen that the addition of glass fibers to the cement matrixreduces the compressive strength of concrete Also by adding pozzolanic materials reduction in the compressivestrength of glass fiber reinforced samples was at least The results show that the addition of glass fibers to thecement matrix significantly improves the modulus of rupture By increasing the amount of glass fiber modulusof rupture first rises and then declines Pozzolanic materials improve the modulus of rupture in glass fiberreinforced concrete Also with aging the reduction in modulus of rupture of GFRC containing pozzolanicmaterials is minimized In this study the area under the load deflection curve is used to obtain the toughness of glass fiber reinforcedconcrete Generally using glass fiber improves toughness of concrete The results show that with increasing theamount of glass fibers all three toughness indices increased However the increase of I5 is negligible In fact this shows that in the larger displacement more energy is absorbed by the glass fibers Using 10 and 15 metakaolin provides the highest mechanical properties for glass fiber reinforced concrete According to thisresearch the use of nano silica causes a reduction in compressive strength bending strength and toughness ofglass fiber reinforced concrete Key words Glass fiber reinforced concrete GFRC Micro silica Metakaolin Nano silica Compressivestrength Bending strength Toughness index

كتيرايي، روزبه

بررسي تاثير الياف و مواد پوزولاني بر روي خواص مكانيكي بتن مسلح شده با الياف شيشه

ميكرو سيليس , متاكائولين , نانو سيليس , مقاومت فشاري , مقاومت خمشي , شاخص طاقت