EFFECT OF NOTCH/DEPTH RATIO ON FRACTURE BEHAVIOUR OF PLAIN CONCRETE

摘要

An experimental investigation on the influence of pre-crack depth, maximum aggregate and specimen size on the fracture behavior of concrete is presented in this paper. Over 200 specimens were tested in the quasi-static cyclic mode of testing. Four different sizes of wedge-splitting concrete specimens were prepared with dimensions varying from (width x total depth x thickness) 210 x 210 x 25 mm to 1680 x 1680 x 200 mm and five different maximum aggregate sizes of 4.75, 9.5, 19, 38, and 76 mm and initial notch/depth ratios of 0.15 and 0.30. Generally, the values associated with the peak load, and toughness (R-curves) were noticeably lower for the long-notch specimens than those of short-notch specimens. The crack trajectory deviated more from the rectilinear path in the specimens with larger aggregate size and the deviation in short-notch specimens was noticeably more than that in long-notch specimens. For same size specimens, an increase in aggregate size resulted in an increase in crack mouth opening displacement (CMOD) and it was more pronounced in short-notch specimens than in long-notch specimens. Less energy absorption in the fracture zone was observed in long-notch specimens than in short-notch specimens that can be characterized by the crack surface interaction (friction).