# Experimental Study on the Flexural Behavior of Alkali Activated Fly Ash Mortar Beams
## 2 Experimental Procedure  
### Design  
In the construction of the beams, the following dimensions were chosen: length L = 1500 mm, width b = 100 mm, and height h = 150 mm. For the longitudinal reinforcing bars, \(\phi\)6 (6 mm) and \(\phi\)8 sizes were assumed with a 10 mm cover. Transversal \(\phi\)4 stirrups were used (a reinforcement factory accepted to supply this special size). Taking into account the reduced covering, it was decided to use sand (maximum particle size of \(\text{Dmax}\leq 2\) mm) without coarse aggregates. It was intended that the reinforcement to be used, as well as the covering, would also be reduced in the same proportionality as the external dimensions of the beams.  
Taking into account the objectives of the test to be carried out, it was intended that the combination of the materials allowed to obtain approximately half of the beams reaching failures by the reinforcement, and the other half by crushing of the mortar. Keeping this in mind, for the five beams to be constructed with each material, the only parameter to be varied, as uniformly as possible, would be the percentage of the reinforcement, which should cover a range of usual values in construction. That is, in addition to the dimensions, the compressed longitudinal reinforcement, the transversal reinforcement and the material in each group of beams remained constant. Obviously, the failure of the middle beam of each group could occur either by the reinforced bars or by crushing of mortar. Table 1 shows the designations adopted for the beams. In this table, \(\phi\) indicates the number and diameter of the tensioned reinforcement of the beam, As the corresponding area, and \(\rho\) the percentage of tensioned reinforcement.  
One of the initial concerns was to obtain failure by bending and not by shear. Since the critical beam would be the one under the greatest loads, it was decided to fix an amount of stirrups, which would prevent shear failure for such beam, and to use the same amount of transverse reinforcement in all the beams. Following this option, identical conditions of material confinement in all beams would also be guaranteed. This parameter is very important in bending beams. This led to 4 mm diameter  
\begin{table}
\begin{tabular}{c c c c c} \hline \hline \multirow{2}{*}{**Binder**} & \multicolumn{3}{c}{**Longitudinal Reinforcing Bars**} & \multirow{2}{*}{**Label**} \\ \cline{2-2} \cline{4-5}  & \(\phi\) **[mm]** & **As [mm\({}^{2}\)]** & \(\rho\) **[\%]** & \\ \hline \multirow{5}{*}{Cement} & 2 \(\phi\) 6 & 56.5 & 0.38 & Insufficiently reinforced & Cem-2F6 \\ \cline{2-5}  & 3 \(\phi\) 6 & 84.8 & 0.57 & Lightly reinforced & Cem-3F6 \\ \cline{2-5}  & 4 \(\phi\) 6 & 113 & 0.75 & Bellow normally reinforced & Cem-4F6 \\ \cline{2-5}  & 3 \(\phi\) 8 & 151 & 1.01 & Normally reinforced & Cem-3F8 \\ \cline{2-5}  & 4 \(\phi\) 8 & 201 & 1.34 & Above normally reinforced & Cem-4F8 \\ \hline \multirow{5}{*}{Fly Ash} & 2 \(\phi\) 6 & 56.5 & 0.38 & Insufficiently reinforced & FA-2F6 \\ \cline{2-5}  & 3 \(\phi\) 6 & 84.8 & 0.57 & Lightly reinforced & FA-3F6 \\ \cline{1-1} \cline{2-5}  & 4 \(\phi\) 6 & 113 & 0.75 & Bellow normally reinforced & FA-4F6 \\ \cline{1-1} \cline{2-5}  & 3 \(\phi\) 8 & 151 & 1.01 & Normally reinforced & FA-3F8 \\ \cline{1-1} \cline{2-5}  & 4 \(\phi\) 8 & 201 & 1.34 & Above normally reinforced & FA-4F8 \\ \hline \hline \end{tabular}
\end{table}
Table 1: Designation of the beams.  
transverse reinforcement bars (\(\phi\)4) made by two branches stirrups spaced 70 mm. In the top of the beam, 2 \(\phi\) 6 longitudinal bars were used. Figure 1 shows the reinforcement before casting.