بررسي خصوصيات بتن با سنگ دانه ي سراميك پرسلان و الياف تحت اثر دما

چكيده انگليسي :

Mechanical properties of concrete with waste porcelain aggregates under elevated temperature Mahtab Talaei m talaeipashiri@cv iut ac ir Date of Submission February 2020 Department of Civil Engineering Isfahan University of Technology Isfahan 84156 83111 IranDegree M Sc Language FarsiSupervisors Dr Davood Mostofinejad dmostofi@cc iut ac ir AbstractNowadays the use of concrete in small and large structures due to its properties has become more andmore popular According to the use of concrete in a variety of structures including those exposed toelevated temperature it is important to improve the physical and chemical properties of concrete Underhigh temperature concrete undergoes physical and chemical changes which reduces its compressive tensile flexural strength and modulus of elasticity and can ultimately damage the structure Concretedeterioration continues for days and weeks after cooling causing the concrete to deteriorate more Asa result using refractory materials in concrete can increase the heat resistance of concrete Variousstudies have been carried out on the properties of concrete under high temperature In many of theseresearches ceramics have been used as aggregates in concrete to increase its heat resistance becausecalcareous aggregates generally decompose by heat and lose their strength Ceramic not only has a highstrength but also high resistance to heat The use of refractory cement as a replacement for Portlandcement also increases the heat resistance of concrete because the concrete made with ordinary Portlandcement loses its strength at temperatures above 600 C The use of polypropylene and steel fibers inconcrete prevents the phenomenon of concrete spalling and increases compressive tensile and flexuralstrength under high temperature In this research waste porcelain ceramic was used as aggregate inconcrete The use of ceramic waste in concrete not only prevents environmental pollution and reuse ofthis material but also improves the concrete properties In this study two types of polypropylene andsteel fibers as well as hybrid fibers a mixture of these two types and two types of ordinary Portlandcement and refractory cement was used In this study air entrained concrete has also been used as anoption to increase heat resistance of concrete For this purpose 220 specimens were made with 18mixing designs At first Specimens made with porcelain ceramic aggregates were placed in the furnaceat temperatures of 400 and 800 C After cooling compressive strength tensile strength weight lossand cracking assessment using fractal dimension were measured Then to investigate the degradationand deterioration of concrete after cooling the mixtures that had the highest compressive and tensilestrength were made with ceramic aggregate and alumina silicate aggregate and placed in the furnace at1000 C and their appearance changes cracking and deterioration were examined for 4 weeks Theresults showed that all samples compressive and tensile strength decreased with increasing temperature but their rate of decline was variable At 400 C samples containing Portland cement and at 800 C samples containing refractory cement showed higher strength Application of steel fibers increased theresistance of the specimens to heat and also reduced cracking The use of polypropylene fibers and air entrained concrete also prevented spalling phenomenon Key words Concrete high temperature heat resistance of concrete porcelain ceramic aggregate polypropylenefibers steel fibers air entrained concrete

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بررسي خصوصيات بتن با سنگ دانه ي سراميك پرسلان و الياف تحت اثر دما

بتن , حرارت , سراميك پرسلان , سيمان نسوز , الياف