الفهرس | Only 14 pages are availabe for public view |
Abstract One of the underlying inciples of fracture mechanics is that unstable fracture occurs when the stress intensity. factor at the crack tip reaches a critical value . This value for mode I deformation and small crack tip plastic deformation is designated Krc. Krc represents the inherent ability of a material to withstand a given stress - field intensity at the crack tip .. and resist progressive tensile crack extension under plane strain conditions . In the present work, the fracture behavior of concrete beams reinforced by steel bars and steel fibers was investigated. The effect of fiber volume fraction, notch - depth and different types of coarse aggregate on the fracture toughness of concrete beam specimens of dimensions 6 x 15 x 65 cm and reinforced with different areas of steel bars were studied The used fiber volume fraction were 0.0 and 1.0 % , the notch / depth ratios were 0.1 , 0.3 , 0.5 and steel bars reinforcement areas were 20 6 mm and 2 0 8 mm. Two different types of coarse aggregate used in the mIX (dolomite and gravel). The flexural strength of unnotched beams of the same dimensions , splitting tensile strength of standard cylinders and compressive strength of standard cubes were measured for the considered fiber volume fraction and for the two types of coarse aggregate mentioned above. |