بررسي ميزان افت ناشي از خشك شدگي در انواع بتن اليافي

چكيده انگليسي :

110 Investigation of drying shrinkage in various fiber concretes Amjad Alhamoud a alhamoud@cv iut ac ir 20 8 2018 Department of Civil Engineering Isfahan University of Technology Isfahan 84156 83111 Iran Degree M Sc Language Farsi Supervisor Dr Kiachehr Behfarnia kia@cc iut ac ir AbstractToday concrete is one of the most widely used construction materials Concrete enjoys severaladvantages over wood and steel and other construction materials such as flexibility in shaping fireresistance durability and ease of production and finally cheaper and more economical But alongwith these advantages there are also disadvantages such as heavy weight low tensile strength andhigh shrinkage In general shrinkage is considered as the commonest cause of cracking Instructural components which their deformation has been limited if related controls are notperformed contraction causes tension and as a result crack so that this can lead to incompetency ofservice durability and shear strength Research results have indicated that the ductility of concrete using fiber can be greatly increased Additionally an overall improvement in application of fiber is increase in tensile flexural and shearstrength Concrete cracking can be delayed and controlled with application of fibers in concreteSubsequently decrease shrinkage Compressive strength of concrete is increased by adding somekind of fibers to concrete mixtures This study investigates the application of Barchip and polypropylene fibers in concrete Also In thisthesis it is aimed to proceed to investigate experimentally and present an analytical model of dryingshrinkage of concrete contains these types of fibers and the factors effective on it In this study concrete mixtures with 0 4 0 6 and 0 8 volume percent of HPP fiber andpolypropylene fibers with two longs 6 and 12 mm were Provided Changes in shrinkage compressive strength and tensile strength were measured relative to the control sample Tomeasure of drying shrinkage of concrete 285 75 75 mm prism specimens were used basedon ASTM C157 standard for 33 mixed design The obtained results showed that thepolypropylene fibers were not effective in compressive strength tensile strength and dryingshrinkage compare to Barchip fibers Also By increase of content of polypropylene fibers to 0 8 drying shrinkage compressive strength and tensile strength decreases but by increase ofcontent of Barchip fibers compressive strength and tensile strength increases To investigateeffect of water to cement ratio amount of this parameter was selected 0 45 0 50 and 0 55 The more increase of water to cement ratio of concrete the more decrease of compressivestrength and tensile strength and also the more increase of drying shrinkage Increase ofdrying shrinkage rate in lower water to cement ratio is more obvious At last according tothe proposed models for ordinary concrete and experimental results a model is presentedto predict drying shrinkage in concretes of this research

حمود، امجد

بررسي ميزان افت ناشي از خشك شدگي در انواع بتن اليافي

بتن اليافي , پلي پروپيلن , بارچيپ , افت خشك‌شدگي , مدل تحليلي افت