## 3 Flexural Loading Tests of Precast Concrete Slab Joints  
### Details of Specimens and Experimental Parameters  
The specimens in the flexural loading tests are presented in Figure 5. Four specimens (Types A-D) were fabricated, and their specifications are listed in Table 3. Four loop reinforcements were arranged into the joint from two PCa slab members with a thickness of 220 mm. The concrete or PVA fiber-reinforced (PVA-FR) mortar was cast into the joint between the two PCa slab members. The joint of the Type A specimen was a conventional loop joint, while that of Types B-D was the proposed narrow loop joint. Therefore, the upper widths of the joints were set to 350 mm for the Type A specimen and 200 mm for Types B-D. Note that the joint was tapered for constructability.  
Figure 5: Test setup and specimen details: (**a**) side view; (**b**) plan view: from bottom of specimen and reinforcements whose strains were measured (red: loop reinforcements, yellow: transverse reinforcements and Pi-shape gauge locations; (**c**) strain gauge locations of loop reinforcements; (**d**) concrete gauge locations; (**e1,e2**) strain gauge locations of transverse reinforcements in Type A loop joint.  
Figure 6 shows the joints of (a) Type A and (b) Type B before casting the joint materials. The diameter of the loop reinforcements of all specimens was 19 mm (D19), and the transverse reinforcements in the joint of the Type A specimen had the same diameter. In the PCa slabs, the transverse spacing of the loop reinforcements was 150 mm, and the spacing of the transverse reinforcements was 125 mm. Furthermore, overlapping lengths of 130 and 170 mm were used for the Type B and C specimens, respectively, as presented in Table 3 and Figure 5c, to investigate the overlapping length of the loop reinforcements for the 200-mm width joint. Plain concrete was also used for the 200-mm width joint of the Type D specimen for comparison with the Type C specimen (PVA-FR mortar).  
A number of the transverse reinforcements in the Type A loop joint were designed by the formula proposed by [PERSON] (2016), which suggests that the crack stress of the loop joint in the transverse direction is about 40% of the tensile force in the longitudinal direction. The required transverse reinforcements in the loop were calculated using Equation (1). Equation (2) was used to calculate the required tensile force of the loop reinforcements in the longitudinal direction.  
\[f_{e,pure}\geq 1.5\cdot\frac{2Z}{5}\cdot\frac{1}{\sigma_{e}} \tag{1}\]  
\[Z=A_{s}\cdot\sigma_{s}\cdot 2 \tag{2}\]  
where  
\(f_{e,pure}\): required cross-sectional area of the transverse reinforcement,  
\(Z\): tensile force acting on the loop reinforcement,  
\(\sigma_{e}\): stress limit of the transverse reinforcement at the serviceability limit state (=120 N/mm\({}^{2}\)),  
\(A_{s}\): cross-sectional area of the loop reinforcement, and  
\(\sigma_{s}\): yield stress of the loop reinforcement (=345 N/mm\({}^{2}\)).  
According to Equations (1) and (2), 3.45 D19 reinforcements were required, and a total of six D19 reinforcements were provided.  
\begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Specimen Name** & **Joint Material** & \
\begin{tabular}{c} **Transverse** \\ **Reinforcement** \\ \end{tabular} & **Joint Width (mm)** &
\begin{tabular}{c} **Overlapping Width of the** \\ **Loop Reinforcements (mm)** \\ \end{tabular} \\ \hline Type A & Concrete & Added & 350 & 280 \\ Type B & PVA-FR mortar & None & 200 & 130 \\ Type C & PVA-FR mortar & None & 200 & 170 \\ Type D & Concrete & None & 200 & 170 \\ \hline \hline \end{tabular}
\end{table}
Table 3: Specifications of flexural loading test specimens.  
Figure 6: Joints before casting joint materials: (**a**) Type A; (**b**) Type B.