چكيده به لاتين
One of the major damages in marine concrete structures is the entry of aggressive ion into the structures through the cracks and bar corrosion. Bonding between bar and concrete with corrosion will be reduced and consequently flexural strength, ductility and service life will be decreased. Using the fibers is one of the delays in cracking or reducing the crack width in concrete. It seems that by reducing the crack width, fibers delay the entry of the aggressive ions and improve the durability and bending behavior of reinforced concrete.
To do so, in the present thesis, the effect of steel, polypropylene and glass fibers on flexural behavior of conventional reinforced concrete in three different environments such as fresh water, atmospheric and tidal zone were studied. Also, bending behavior of steel fiber reinforced concrete beams with different water to cement ratios, cracks and fiber lengths in tidal zone were evaluated. Based on results in bending discussion, in three environments, the greatest improvement in flexural behavior of conventional reinforced concrete was related to the addition of steel fibers. The beams containing bar and glass fibers had the minimum of flexural strength. On the other hand, in marine structures and tidal zone, if water to cement ratio is changed from 0.5 to 0.4, in order to fix the flexural strength, fiber lengths can be increased. In average residual strength section, by changing the environment from fresh water to marine tidal zone and increase of fiber length, the reduction of average residual strength will be more.
Keywords: steel fiber, glass fiber, polypropylene fiber, flexural strength, toughness.
