# Effect of Load Transfer Section to Toughness for Steel Fiber-Reinforced Concrete
## 1 Introduction
The evaluation methods based on absolute values do not have the same issue concerning the accurate selection of the initial crack point, but the end point corresponding to 1/150 of the span, which is usually selected in the test, is larger than the deflection limit that considers the usability of the regulations on fiber-reinforced concrete, and the difference in behavior before and after the initial crack occurrence can be distinguished; as such, the mixes with different load deflection curves cannot show the same toughness [8; 16]. Such a symptom results in a small amount of load reduction after the first peak load in the flexural load displacement graph of steel fiber-reinforced concrete [17]. The small-reduction section in the graph generated by the differences in the physical properties of the two materials determines the starting location of the nonlinear graph that continues, and therefore, the energy transfer capacity in the load transfer section is believed to greatly influence the nonlinear section, which occupies most of the graph. To improve the issues of the various toughness evaluation methods existing today, improvement measures should be applied equally to each specimen. Therefore, with the aim of evaluating the correlation in the overall toughness, this study conducted an assessment based on absolute values, and extracted a regression analysis model by analyzing the different load transfer properties based on the \begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**Name of** & **Dimensions of the** & **Rate of** & **Type of Loading** & **Maximum** & **Toughness** \\
**Standard** & **Specimen** & **(mm/min)** & **Arrangement** & **Measured** & **Measurement** \\ \hline JSC SF-4, & \multirow{2}{*}{\(100\times 100\times 300\)} & L/1500 to & \multirow{2}{*}{4-point bending test} & \multirow{2}{*}{L/150} & Energy absorbed up to a \\ JCI SF-4 & & & L/1300 & & deflection of L/150 mm \\ \hline EFNARC & \multirow{2}{*}{\(75\times 125\times 450\)} & \multirow{2}{*}{\(0.25\pm 0.05\)} & \multirow{2}{*}{4-point bending test} & \multirow{2}{*}{25} & Residual strength factors \\  & & & & & up to deflection of 1 and \\ \hline KS F 2566 & \multirow{2}{*}{\(100\times 100\times 400\)} & \multirow{2}{*}{0.1–0.2} & \multirow{2}{*}{4-point bending test} & \multirow{2}{*}{L/150} & Energy absorbed up to a \\  & & & & deflection of L/150 mm \\ \hline ASTM C & \multirow{2}{*}{\(100\times 100\times 400\)} & \multirow{2}{*}{0.05–0.10} & \multirow{2}{*}{4-point bending test/3-point bending test} & \multirow{2}{*}{L/150} & Energy absorbed up to a \\  & & & & bending test & \\ \hline French & \multirow{2}{*}{\(140\times 140\times 560\)} & \multirow{2}{*}{0.05–0.10} & \multirow{2}{*}{4-point bending test} & \multirow{2}{*}{2.8} & Ratio of load at deflection \\ Standard & & & & (0.7 mm, 1.4 mm, 2.8 mm) \\ P18-409 & & & & to load P \\ \hline ACI 544 & \multirow{2}{*}{\(100\times 100\times 350\)} & \multirow{2}{*}{0.05–0.10} & \multirow{2}{*}{4-point bending test} & \multirow{2}{*}{1.9} & Ratio of energy absorbed \\  & & & & bending test & up to deflection of 1.9 mm \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Experimental test methods and toughness characterization by various standards. fiber type and the variation of the fiber contents (by volume) in the load transfer process to fiber after the concrete matrix cracking, and by extracting the key factors contributing to fracture delay in the fiber section. The comparison with the reinforcing rebar is not meaningful in this study due to totally different stress distribution and feature mechanism compared to the fiber-reinforced concrete.