## 3 Discussion of Results  
Considering the achieved load-deflection diagram (Figures 4-6), the calculated parameters were \(P_{max}\),\(f_{r}\), \(T\), and \(S.S\) of PC, SFRC, RC, and (R+S)C beams in marine atmosphere, tidal zone, and fresh water (according to Tables 4 and 5). In term of \(f_{r}\), \(T\) and \(S.S\) definitions: \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline  & \multicolumn{3}{c}{\(P_{max}\) (kN)} & \multicolumn{3}{c}{\(f_{r}\) (MPa)} \\ \cline{2-7}
**Mixture Index** & **28 (Days)** & **90 (Days)** & **180 (Days)** & **28 (Days)** & **90 (Days)** & **180 (Days)** \\ \hline PC (Tl) & 74.05 & 60.21 & 53.97 & 6.02 & 4.89 & 4.39 \\ Variation (\%) & 5.61 & 3.24 & 5.65 & 5.61 & 3.24 & 5.65 \\ SFRC (Tl-Un) & 108.43 & 80.64 & 67.04 & 8.81 & 6.55 & 5.45 \\ Variation (\%) & 4.63 & 5.61 & 3.35 & 4.63 & 5.61 & 3.35 \\ RC (Tl-Un) & 174.11 & 149.61 & 131.55 & 14.15 & 12.16 & 10.69 \\ Variation (\%) & 3.12 & 4.41 & 4.25 & 3.12 & 4.41 & 4.25 \\ (R+S)C (Tl-Un) & 198.54 & 170.16 & 156.02 & 16.13 & 13.83 & 12.68 \\ Variation (\%) & 4.15 & 3.31 & 2.59 & 4.15 & 3.31 & 2.59 \\ SFRC (Tl-Pr) & 69.66 & 55.55 & 50.44 & 5.66 & 4.51 & 4.10 \\ Variation (\%) & 2.61 & 2.59 & 3.35 & 2.61 & 2.59 & 3.35 \\ RC (Tl-Pr) & 180.03 & 141.65 & 125.29 & 14.63 & 11.51 & 10.18 \\ Variation (\%) & 4.59 & 6.61 & 2.65 & 4.59 & 6.61 & 2.65 \\ RC (MA-Pr) & 174.28 & 148.49 & 144.06 & 14.16 & 12.07 & 11.70 \\ Variation (\%) & 3.35 & 4.49 & 2.68 & 3.35 & 4.49 & 2.68 \\ RC (W-Pr) & 201.39 & 172.08 & 168.90 & 16.36 & 13.98 & 13.72 \\ Variation (\%) & 3.19 & 2.89 & 3.78 & 3.19 & 2.89 & 3.78 \\ (R+S)C (Tl-Pr) & 156.70 & 165.54 & 181.45 & 12.73 & 13.45 & 14.74 \\ Variation (\%) & 2.61 & 2.65 & 3.65 & 2.61 & 2.65 & 3.65 \\ (R+S)C (MA-Pr) & 158.47 & 168.93 & 183.10 & 12.88 & 13.73 & 14.88 \\ Variation (\%) & 5.41 & 5.42 & 3.25 & 5.41 & 5.42 & 3.25 \\ (R+S)C (W-Pr) & 167.01 & 195.11 & 205.78 & 13.57 & 15.85 & 16.72 \\ Variation (\%) & 2.65 & 3.54 & 1.12 & 2.65 & 3.54 & 1.12 \\ \hline \hline \end{tabular}
\end{table} 
Table 4: Maximum load capacity (\(P_{max}\)) and Flexural Strength (\(f_{r}\)) results. Figure 3: Beams condition in the Oman Sea. (**a**) Sea environment; (**b**) beams. As can be known, \(f_{r}\) as a flexural strength is calculated from \(P_{max}\) (Equation (1)) [22]:  
\[f_{r}=P_{max}L/bh^{2} \tag{1}\]  
where \(L\) is span length (650 mm), \(b\) is the average width (200 mm), and \(h\) is the average depth of the beam (200 mm). The \(T\) is a measure of the energy absorption capacity of the beam, which is calculated by the area of the load-deflection diagram up to a specific point, such as maximum deflection [23]. A comparison of the \(T\) cannot be easily carried out for beams with fiber and bar, as it is quite difficult to identify a maximum deflection. However, in this study for calculating the \(T\), maximum deflection was selected 15 mm for all of the beams. \(S.S\) values were determined as the slope of the load-deflection diagram following the initiation of flexural cracking, and were obtained by calculating the line slope between the two points corresponding to 50% and 80% of the \(P_{max}\) on the ascending branch of the load-deflection diagram [20]. After the determination of result data and plot of diagrams for each mixture series, the trend of diagrams was determined and drawn. Scatter of the diagrams was generally related to small changes in temperature and the humidity condition at the time of making the concrete and error in the sensitivity of machine sensors in the record of the diagram. The average flexural load-deflection diagram was shown in Figures 4-6. In following sections, by measured values from Load-Deflections diagram effect of steel fibers on \(P_{max},f_{r}\), \(T\) and \(S.S\) of PC and RC beams (un-cracked and pre-cracked) in marine atmosphere, tidal zone, and fresh water will be studied. In the water conditions, \(P_{max(\text{Pr-RC})28}\) and \(T_{\text{(Pr-RC)28}}\) by addition of steel fibers were decreased about 16%.