effects of hybrid fiber on flexural behavior of green rc beams in oman sea

Steel rebar corrosion because of the cracks in marine reinforced concrete (rc) structures is the main type of deterioration that leads to decrease the loadcarrying capacity, ductility, and service life. the use of different fibers such as steel fiber (sf), glass fiber (gf), and polypropylene fiber (pf) in rc beams can reduce the cracks and increase the loadbearing capacity and toughness of rc beams. moreover, it seems that rc beams containing hybrid of sf, gf, and pf have been higher flexural capacity and toughness rather than rc composites with only one type of fiber. however, the role of mono or hybrid fiber will be depended on environmental conditions. consequently, loadbearing capacity and toughness of green rc beam with 15% metakaolin (mk) as a cement replacement, containing sf, pf, gf, (s+p)f, and (s+g)f as fibers, at 28, 90, and 180 days in tidal zone of oman sea were determined. the dimension of the beams was 200×200×750 mm. the fibers included macro and microfibers. macro fiber was steel with 50 mm length. microfibers were gf and pf with 12 mm length. results indicated that by the addition of pf, gf, sf, (s+p)f, and (s+g)f to rc beams the loadbearing capacity and toughness are increased up to 41%. meanwhile, the hybrid effect of fiber was more than the mono one.