بررسي آزمايشگاهي دوام رو سازي هاي بتني متخلخل

چكيده انگليسي :

Experimental Study of Durability of Pervious Concrete A R Hejazi hejaziahmad@gmail com Date of Submission April 13 2011 Department Collage of Civil Engineering Isfahan University of Technology Isfahan 84156 83111 Iran Degree M Sc Language FarsiSupervisor Dr K Behfarnia kia@cc iut ac ir Dr M Abtahi mabtahi@cc iut ac ir AbstractPortland cement pervious concrete PCPC is one of the many kinds of concrete PCPC mixture hasno or a little 0 20 fine aggregate The main specification of this kind of concrete is the highpermeability of it because of its connected void structure with void content of 15 30 ACICommittee 522 The most important advantage of PCPC is controlling storm water pollution at thesource controlling storm water runoff reducing tyre spray and reducing hydroplaning One of theapplications of PCPC is in pavements Low compressive strength of PCPC is one of thedisadvantages of PCPC For this reason pervious concrete pavement is used in low traffic areassuch as parking lots sidewalks and other paved areas On other hand there is no enough study onsulfate attack on PCPC and this subject is mentioned in ACI522R Due to pavement application ofPCPC it seems that scrutiny of sulfate attack is very important By using a method similar toASTM C1012 durability of PCPC in magnesium sulfate solution was measured For mixturedesign ACI211 3R method was used This report explained selecting proportion of materials forzero slump concretes The work was aimed at studying the effects of various factors including fibrecontent silica fume content and w c ratio of PCPC samples A mechanism was handled tomeasuring permeability It was based on falling head of water on pervious concrete and by usingDarcy equation k permeability coefficient was calculated The obtained results show that theapplication of polypropylene fibres in pervious concrete will statistically increase the compressivestrength and durability considerably and using silica fume in PCPC decrease them Using 0 9Kg m3 polypropylene fibers in pervious concrete mixture improved compressive strength 25 88 But adding 1 5 kg m3 cause inverse effect Polypropylene fibers in pervious concrete author risingvoid content and permeability Also usage of silica fume in pervious concrete mixture has similareffect By increasing permeability intensity of destruction in magnesium sulfate was more Insofaras specimens were included 10 silica fume was destructed completely at the end of period of 135days Also by attack of sulfate ion to C S H and creation of M S H in attendance of silica fume theweakness was occurred in pervious concrete intently Only the mixture was included 0 9 kg m3polypropylene fibers has compressive strength at the end of 180days period Decay of PCPCstarted from corners and extended to other points by creation of cracks In other hand by increasingdensity of magnesium sulfate solution from 5 to 10 a reduction was occurred in durability ofpervious concrete And durability of specimens was declined by elapsing time from 90 days to 135and 180 days Another outcome of this research is bad effect of superplasticizer to perviousconcrete Superplasticizer causes a heterogeneous in mixture and occasion flowing paste The pastewas clogged voids of pervious concrete and reduces permeability KEYWORDS pervious concrete durability polypropylene sulfate attack permeability compressive strength

حسين زاده حجازي، احمدرضا

بررسي آزمايشگاهي دوام رو سازي هاي بتني متخلخل

نفوذپذيري , الياف پلي پروپيلن , حمله سولفات