Strength of Different Fiber Reinforced Concrete in Marine Environment

In this paper, the compressive strength, tensile strength and growing rate of compressive strength in 3, 7, 28 and 90 day ages for steel, polypropylene and hybrid steel-polypropylene fiber reinforced concrete with different water to binder ratios (0.4 and 0.5) in a real marine condition and tidal zone were determined. Moreover, regarding a large number of gathered data from the other researches, new equations between compressive strength, tensile strength and elasticity modulus for different types of steel fiber reinforced concrete were proposed. Finally, proposed equations were compared and verified for a marine environment. Based on marine environment results, compressive strength of polypropylene and hybrid steel-polypropylene fiber reinforced concrete were about 18 % and 5 % greater than plain concrete in 90 day ages, respectively and steel fibers had not meaningful effect on compressive strength in 90 day ages. By increasing the water to binder ratio, the compressive strength of plain concrete and steel fiber reinforced concrete was decreased about 18 % and 25 %, respectively. Also in 28 and 90 days, steel fiber reinforced concrete tensile strength was increased about 15 % in 0.4 water to binder ratio and 20 % in 0.5 water to binder ratio rather than plain concrete. Effect of steel fiber in increment of plain concrete tensile strength in 0.5 water to binder ratio was higher than 0.4. Steel fiber reinforced concrete elasticity modulus was lower than related plain concrete and with increasing the compressive strength, the difference between elasticity modulus of steel fiber reinforced concrete and plain concrete was decreased.