A novel method of predicting shear strength of fiber?reinforced high?strength concrete based on cube specimens: part?1

摘要

Shear failure in concrete structures is sudden and catastrophic. From past few decades, the shear behavior of concrete of variouskinds is studied but even today there is no one universally accepted single shear test setup acceptable to all wide rangeof concrete. In this study, a novel method of predicting shear strength is proposed. From the literature and different standardcodes, it is found that, shear strength of plain concrete becomes constant beyond certain compressive strength which ismentioned differently in various codes and researchers. The aim was to improve the shear strength of HSC by using crimpedsteel fibers (CSF). In this part of investigation, two aspect ratios, i.e., 60 and 100, with four fiber dosages of 0, 0.25, 0.50,and 0.75 by volume of concrete were considered for improving shear strength of concrete compressive strength rangingfrom 50 to 80 MPa. To understand the significance of size of aggregates, two different nominal sizes viz., 12.5 and 20 mm,were considered. A total number of 378 specimens, which includes cubes and cylinders were cast and tested to determine thecompressive strength, shear strength, and split tensile strength of HSC. From experimental results, it was found that, the idealdosage of steel fibers for HSC was 0.50 and 0.75 for improvement of compressive strength, shear strength, and for split tensilestrength, respectively. Further, it was found that 12.5-mm aggregate provides greater compressive, split tensile, and shearstrengths compared to 20-mm aggregate. Fibers with aspect ratio 100 were shown to improve the compressive, split tensile,and shear strengths. The experimental shear strength results are compared with various models proposed on different sheartest setups and found Khanlou et al., and Khaloo and Kim models are in good co-relation with experimental shear strength.Except for Sharma model, various models proposed on deep beams are not in good correlation with experimental results.