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چكيده انگليسي :

The Effect of Pozzolans on Durability of Self Consolidating Concrete in Magnesium Sulfate Environment Omid Farshadfar Omid1197@yahoo com May 2011 Civil Engineering Isfahan University of Technology Isfahan 84156 83111 IranDegree M Sc language FarsiSupervisor K Behfarnia Email Kia@cc iut ac irAbstractSelf compacting concrete SCC also referred to as self consolidating concrete is able to flow and consolidate underits own weight and fill the workform without need for vibration It is cohesive enough to fill the spaces of almostany size and shape without segregation or bleeding This makes SCC particularly useful wherever placing isdifficult such as in heavily reinforced concrete members or in complicated workforms The main differencebetween self consolidating concrete and regular concrete is the fresh properties of them Workability of SCC isdescribed in terms of filling ability passing ability and stability and is characterized by specific testing methods Obtaining these features makes SCC a mix with less coarse aggregates and more binder than regular concrete Themain goal of this research was to study the effect of pozzolans on the durability of SCC in the sulfate environment Sulfate effects on SCC could be studied by measuring the variation of compressive strength volume and weight ofspecimens Thus to control the effect of magnesium sulfate consistency on the durability of concrete two solution of5 and 10 of magnesium sulfate were made Twenty two SCC mixtures with water to cementitious materials ratio W CM of 0 38 were prepared using single and binary binders The mixtures were divided into two groups Thesetwo groups of mixtures contained 0 and 0 1 poly propylene fibers PP by volume respectively The single binderwas made by 100 type I Portland cement The binary binders contained silica fume 5 10 15 metakaolin 5 10 15 and Zeolite 5 10 15 that were replaced with the same weight of cement Difference betweencompressive strength volume and weight after 3 6 and 9 months of specimens those were immersed in the 5 and10 magnesium sulfate with the specimens those were immersed in water were noticed Also some specimens weresubjected to wet and dry cycles to study the durability of the concrete under wet and dry condition Microstructureimages of four different types of concretes which had 10 silica fume 10 metakaoline 10 zeolite and withoutpozzolan were observed by SEM test Also the EDX analyses were carried out to show the ingredients of fourdifferent concretes after being nine months in the 10 sulfate magnesium solution To perform a statistics analysisof the data which had obtained from the experimental program variance analysis was carried out by using SASsoftware Results of the analysis showed that using silica fume would reduce the durability of concrete in themagnesium sulfate environment It is also concluded that both metakaoline and zeolite would increase durability ofthe concrete but the effect of metakaoline is more than that of zeolite It was seen that using PP fibers would reducethe volume increase and weight decrease of the specimens were immersed in the magnesium sulfate solution Effectof the silica fume metakaoline and zeolite on the fresh and mechanical properties of the SCC specimens with andwithout PP fibers is also considered in this research The slump flow T50 and V funnel test were carried out fordetermining the properties of fresh concrete It was seen that using VMA is necessary for gaining the stability ofmetakaoline concrete Zeolite would decrease the fluidity and increase the stability of the SCC and PP fiber wouldincrease its viscosity Key Words Self Consolidating Concrete Silica fume Metakaoline Zeolite Poly Propylene MagnesiumSulfate

فرشادفر، اميد

بررسي تاثير انواع پوزولان بر دوام بتن خود متراكم در برابر محيط سولفات منيزيم

ميكروسيليس , بتاكائولن , زئوليت , الياف پلي پروپيلن