Variation of Fracture Parameters of Concrete with Size – An Experimental Study

Fracture mechanics is a field of solid mechanics interested with the behaviour of materials under certain loads their distribution and finally the fracture criteria of given materials.This Paper evaluates size dependency of fracture parameters, fracture energy (Gf) and fracture process zone effective length (Cf) of concrete concluded as per Bazant’s size effect method. Fracture mechanics standards are powerfully applied to the quasi-brittle materials like concrete. Behaviour of concrete ruled by the fracture parameters fracture energy (Gf) and fracture process zone effective length (Cf) the brittleness of plain concrete depends upon these fracture parameters (Gf ,Cf).The fracture parameters were concluded by calculating the ultimate load on geometrically similar notched plain concrete beams samples. Beams are tested with dissimilar precast notch depths (a/d=0.15,0.30,0.45) below three point bending in UTM over load deflection curve. 9 beams samples with 3 similar samples are tested in each size of the beams the numbers of beams approved is 27.The change in both fracture parameters fracture energy (Gf) and fracture process zone effective length (Cf) of concrete which are dependent on specimen size and notch depth was estimated by Bazant’s size effect method. Fracture energy and fracture process zone effective length (Gf ,Cf) calculated from size effect method of Bazant’s is found to be decreasing with increasing notch-depth ratios.The fracture parameters fracture energy and fracture process zone effective length of concrete (Gf ,Cf) is found to be increasing with increasing the specimen size for same notch depth ratio. The variation in critical stress intensity factor (KI) with different size and notch-depth ratio is also observed.