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 steelpolypropylene 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.
In recent years, extensive studies have been conducted to ensure the safety and stability of concrete dams. The development of numerical methods in considering more factors affecting the response of dams and also increasing the accuracy of calculation methods has played an important role in ensuring the safety of concrete dams. Therefore, one of the most important points in the design and analysis of concrete dams is to predict the location of cracks, expand it, investigate the phenomenon of hydraulic failure, consider the pressure caused by the infiltration of reservoir water into cracks and joints in static and dynamic states, and find solutions prevention of dam destruction due to this phenomenon. In the study of the effect of tensile strength, with increasing tensile strength, the reservoir water level increases at the beginning of cracking and the final reservoir water level increases, but there is no linear relationship between tensile strength and the two responses. In general, in examining the refractive energy parameter in each of the states with and without taking into account the water pressure inside the crack, the results of the mentioned models are slightly different from each other, but comparing the results shows that in nonlinear analysis considering water pressure inside the crack failure energy change has a greater impact on the results of these models.
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 load-bearing 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, load-bearing 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 load-bearing capacity and toughness are increased up to 41%. Meanwhile, the hybrid effect of fiber was more than the mono one.
In a year, millions of forms of plastic are produced, and approximately, half of the generated plastics are used once only. Incorrect and insufficient management of these waste materials causes adverse effects on the nature of the soil, water, humans, and animals’ life. One type of waste plastic is metalized plastic waste (MPW), which is used mainly in different types of food packaging productions, and there is no appropriate technology for reusing it all over the world. In this paper, the effect of MPW as a fiber by 0.5% and 1% on compressive, flexural load capacity, and toughness of green concrete containing 7.5% and 15% silica fume or natural zeolite in Oman Sea tidal zone environment at 28, 90, and 180 days was investigated. The results indicate that by adding the MPW fiber, the compressive strength and maximum flexural load capacity of green concrete were decreased 25% and 15%, respectively. Meanwhile, the effect of MPW fiber on concrete containing 15% silica fume was greater than 7.5% silica fume concrete. Flexural toughness of natural zeolite concrete containing 0.5% MPW fiber was up to 510.9% greater than the observed one. Moreover, the toughness of green concrete containing 1% MPW fiber and zeolite was up to 35% greater than 0.5% MPW concrete. Meanwhile, the effect of MPW fiber on flexural toughness of concrete containing 15% natural zeolite was greater than 7.5% natural zeolite concrete.
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