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چكيده انگليسي :

Evaluation of Fiber Low Cement Self Compacting Concrete Seysd Amir Najafi Almousavi a najafi@cv iut ac ir June 8 2015 Department of Civil Engineering Isfahan University of Technology Isfahan 84156 83111 IranDegree M Sc Language FarsiSupervisor Mohammad Reza Eftekhar Assist Prof eft@cc iut ac irAbstractSelf compacting concrete Features especially in the fresh phase the necessity of using relatively highamounts of cement in this material is inevitable High consumption of cement in addition to increasingeconomical costs environmental pollution and excessive energy consumption followed difficulties dueshrinkage of concrete and increase degree of hydration that are not favorable Nowadays need to reduction ofcement consumption by adopting various methods or replacement part of cement with material that does notjeopardize cement paste performance in terms of strength and durability everyone has been proven In thisresearch the feature of low cement self compacting concrete is studied Much previous research has beendone to reduce the consumption of cement more focused on the replacement of cement with filler materialsand other adhesive materials such as limestone and pozzolans For achievement to the purposes of research in addition to replacement part of cement with other filler materials has also been noted to particle sizedistribution materials especially to optimized packing density of aggregates In this regard among of curvesand models of packing density of aggregates has used of modified Anderson curve for achieve to the bestparticle size distribution and highest density In this study first the effect of parameters such as the size oflimestone powder sizes 40 and 150 microns the length of the fiber 6 and 12 mm the percentage of use ofpolypropylene fiber 0 05 0 1 0 15 and 0 2 volumetric weight percent of fiber the percentage of volumetricreplacement of natural zeolite with cement 15 20 and 25 per cent and the distribution modulus of aggregatein modified Anderson curve 0 2 0 4 0 3 0 25 and 0 5 on the fresh and hardened properties of selfcompacting mortar has been studied Then flexural and compressive samples of concrete based on optimummixing of the mortar designs resulting from the first step of research built and has been tested In study of theproperties of fresh mortar mini slump flow and mini V funnel test and for self compacting concrete slumpflow tests T50 test v funnel and visual stability index VSI has been examined The results of tests in thisresearch shows that suitable distribution modulus of aggregate for achievement to desirable fresh andhardened properties in self compacting concrete is in the range of 0 25 0 3 Concrete made on the basis ofaggregate distribution modulus equal 0 5 show suitable hardened and weak fresh properties As well as insome cases bleeding and particle segregation observed Self compacting concrete containing 0 1 percentpolypropylene fibers has more flexural and compressive strength than concrete without fiber Replacing 15 of cement volume with zeolite increase compressive and flexural strength of self compacting concrete thoughthe slump flow of concrete containing zeolite and fiber reduce and concrete viscosity increases In thisresearch reduction of self compacting concrete powder down to 300 kg per cubic meter also is studied Theresults of this part of research show that in samples with the amount of powder less than 400 kg the freshproperties of self compacting concrete well not respect and to preserve the properties of concrete withinacceptable and standards scopes proper use of water and super plasticizer is necessary Key Words Self compacting concrete Fiber Zeolite Modified Anderson curve Aggregate Optimum Packing Density

نجفي الموسوي، امير

ارزيابي بتن هاي خودمتراكم كم سيمان اليافي

الياف , زئوليت , منحني اصلاح شده اندرسون , چگالي چيدمان بهينه ي سنگ دانه