## 3 Results and Discussion
### Load-Displacement Relationship  
The displacement of the RC member was measured at each load levels by the LVDT installed at the center of the RC member. The load-displacement curves of the RC members are shown in Figure 5. Furthermore, Table 7 shows the initial cracking load, yielding load, peak load, and displacement for each specimen. The initial cracking load could be specified at the end point of the linear relationship between the load and relative displacement of the RC members. Furthermore, the yielding load is determined from the reading values of the strain gauges placed on the reinforcing rebar at mid-span. The peak load is the maximum load of the load-displacement curve. As shown in Figure 5 and Table 7, the initial crack load was the largest for the 35 OPC-0 case, and it was affected by the water-binder ratio and heavyweight waste substitution ratio. In general, the yield point depends on the tensile capacity of the reinforcement. The yielding load is considered to be similar regardless of the heavyweight waste glass substitution ratio. However, the yield point is changed slightly, and there was no trend. Therefore, the structural test error was included. Meanwhile, the maximum load of the RC member was affected by the heavyweight waste glass substitution ratio. The load capacity of the RC member was reduced gradually on the large deformed stage when all the fine aggregate was replaced by heavyweight waste glass. Particularly, the 55 OPC case exhibited a relatively low strength than other W/B ratios; therefore, even if the heavyweight waste glass is substituted with only 50% of the fine aggregate, the load capacity \begin{table}
\begin{tabular}{c c c c c c c c c} \hline \hline
**Specimen ID** & \multicolumn{3}{c}{**35 OPC**} & \multicolumn{3}{c}{**45 OPC**} & \multicolumn{3}{c}{**55 OPC**} \\ \hline H.R & 0 & 50 & 100 & 0 & 50 & 100 & 0 & 50 & 100 \\ \hline Number of cracks (ea) & 5 & 5 & 7 & 5 & 6 & 6 & 7 & 6 & 4 \\ \hline Mean. crack spacing (mm) & 101.69 & 101.46 & 84.27 & 103.85 & 92.67 & 85.31 & 79.11 & 98.99 & 134.15 \\ \hline Area of compression & \multirow{2}{*}{710.6} & \multirow{2}{*}{1447.2} & \multirow{2}{*}{1120.7} & \multirow{2}{*}{9450.2} & \multirow{2}{*}{8668.7} & \multirow{2}{*}{11,988.7} & \multirow{2}{*}{3167.1} & \multirow{2}{*}{6250.3} & \multirow{2}{*}{9214.2} \\ crushing (mm\({}^{2}\)) & & & & & & & & \\ \hline Specimen ID & \multicolumn{3}{c}{45 FA20} & \multicolumn{3}{c}{45 BF550} \\ \hline H.R & 0 & 50 & 100 & 0 & 50 & 100 & \\ \hline Number of cracks (ea) & 4 & 7 & 6 & 6 & 7 & 7 \\ \hline Mean. crack spacing (mm) & 108.57 & 81.18 & 71.91 & 90.54 & 86.51 & 79.73 \\ \hline Area of compression & \multirow{2}{*}{-} & \multirow{2}{*}{2488.6} & \multirow{2}{*}{8917.2} & \multirow{2}{*}{-} & \multirow{2}{*}{1761.5} & \multirow{2}{*}{10521.2} \\ crushing (mm\({}^{2}\)) & & & & & & & \\ \hline \hline \end{tabular}
\end{table} 
Table 6: Results of experimental test for RC member (Crack). is reduced. The mineral admixture, however, improved the load capacity of the RC member substituted heavyweight waste glass as all the fine aggregate. The load-displacement curves of the RC members were affected by the heavyweight waste glass substitution ratio. However, the effect of heavyweight waste glass could be reduced using a relatively low water-binder ratio or mineral admixture.