بررسي آزمايشگاهي تاثير انواع پوزولان بر دوام بتن خود متراكم معمولي و اليافي در برابر چرخه هاي يخ و ذوب

چكيده انگليسي :

An Experimental Study on the Effect of Pozzolans on Durability of Conventional and Fiber Reinforced Self Compacting Concrete in Frost Exposure Mohammad Ali Asgari Renani asgarimail@yahoo com April 19 2012 Department of 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 is a new type of concrete to which considerable importance has beenattached by researchers manufactures and users because of specific characteristics that have shown in freshstate and it is now being frequently used in the world With respect to characteristics expected by selfcompacting concrete and in order to achieve self compactibility it is essential to use more powder materialsin it in comparison with conventional concrete To do so pozzolans are generally used to make SCC Service life of concrete is a time that in which concrete is sufficiently strong to the design load and concretedurability is one of the factors that has considerable influence on the service life of concrete a durableconcrete has more resistant to chemical and physical attacks Freezing and thawing is one of the physicaldestructive factor and if a concrete has not enough resistance regarding freeze thaw cycles it will deterioratein a time period much shorter than its service life by being exposed to their attacks This research aims toinvestigate and compare the pozzolans effects on Frost resistance of conventional and fiber reinforced selfcompacting concrete The effect of freezing and thawing on concrete can be analyzed through measuringcompressive strength and length weight and water absorption changes in concrete samples Water cementratio is one of the most important parameter that has a considerable effect on frost resistance of concrete Hence water cement ratio was considered constant in this study The pozzolans used in this study weresilicafume metakaolin and zeolit and the polypropylene fibers were used to reinforce the concrete The mixtures were divided into two groups These two groups of mixtures contained 0 and 0 1 polypropylene fibers PP by volume respectively The single binder was made by 100 type I Portland cement The binary binders contained silica fume 5 10 Metakaolin 5 10 and Zeolite 5 10 that werereplaced with the same weight of cement In addition in order to a better study of the effect of fibers onconcrete durability on frost resistance the volumetric fiber ratios of 0 05 and 0 15 were only used in themixtures containing 10 silicafume To investigation the combined effect of pozzolans 3 mixtures withcombining 3 above mentioned pozzolans were made 5 of each pozzolans was used in any combination Therefore 19 mixtures were obtained that with respect to the number of required specimen to conduct theexperiments 18 totally 342 cubic specimens with dimensions of 10 cm were made The specimens weretested under freezing and thawing conditions according to ASTM C666 B standard To compare the mixturesagainst freeze thaw cycles the change in length weight and water absorption ratio and compressive strengthof specimens were analyzed The results show that replacing percentage of cement with a pozzolan can have a positive and remarkableinfluence on frost resistant of SCC Among the pozzolans used in this study the silicafume had the greatestimpact of compressive strength Although Zeolit had no effect on increase of compressive strength adesirable performance against freeze thaw perceived in this regard Use of fibers PP for the purpose ofconcrete durability against freeze and thaw have been positive assessed Key words Self compacting concrete SCC Concrete durability Freeze and thaw Pozzolan Polypropylene fiber

عسگري رناني، محمدعلي

بررسي آزمايشگاهي تاثير انواع پوزولان بر دوام بتن خود متراكم معمولي و اليافي در برابر چرخه هاي يخ و ذوب

دوام بتن در برابر يخ و ذوب , الياف پلي پروپيلن