SIZE EFFECT OF PLAIN CONCRETE BEAMSVAN EXPERIMENTAL STUDY

T. Muralidhara Rao, T.D.Gunneswara Rao

Abstract: The paper analyses the size dependency of the fracture energy (GF) and the effective length of fracture process zone (Cf) of concrete determined as per the Bazant’s Size effect method and RILEM Work-of-fracture methods. The fracture parameters (GF,Cf) are determined by measuring the maximum loads of geometrically similar notched plain concrete (M25) specimens of different sizes in a size ratio of 1:5 with different pre-cast notch depths (a/d=0.15, 0.30 and 0.45) under three point bending through load-deflection curves. In each notch depth ratio, 15 beams are cast and tested with 03 similar specimens in each size of the beams. Total beams tested are 45.The variation of both the fracture energy and the effective length of fracture process zone as a function of the specimen size and notch depth is determined using Bazant’s Size effect method and RILEM Work-of-fracture method. Fracture energy and Fracture process zone length determined by Size effect method are found to be decreasing with the increasing notch depth ratios. Fracture energy calculated using Work-of-fracture method is increasing with the increase in size of specimen and decreasing with the increasing notch depth ratios

Keywords: Brittleness number, Characteristic size, Crack length, Effective length of fracture process of zone, Fracture parameters, Fracture energy, Notch-depth ratio, Size effect

DOI: https://doi.org/10.15623/ijret.2013.0206023