# Experimental Study on the Flexural Behavior of Alkali Activated Fly Ash Mortar Beams
## 3 Test Results
However, the modulus of elasticity in State II is noticeably smaller for the fly ash beam when compared to cement beam. This means that the first beam is more flexible than the second one. Table 4 shows some further information related to the tests. The \"curing\" refers to the age of the beam in the day of testing, \(\Delta\)T is the duration of the test, and \"failure by\" means the type of failure shown in the tests, whether by the tensioned reinforcement, \"As\", by crushing the compressed material, \"fc\", or by failure of the stirrups, \"V\". Thus, all beams were tested in the time ranging from 31 to 37 days. In the case of insufficiently reinforced or lightly reinforced beams, the failure occurred due to the failure of the tensioned reinforcement, as expected. In the other cases, the failures occurred due to crushing of the compressed material, except for the FA-3F8 beam, where the failure occurred in a shear crack, in this case due to insufficient connection of the stirrup to the surrounding material (this was observed during the visual inspection of the zone after the test). Figure 9: P-d experimental curves for beams Cem-4F8 and FA-4F8. Table 5 shows the values obtained from the curves of the tested beams. Some conclusions are obvious. For example, yield and maximum loads increase as the maximum pulling force on steel increases (due to higher values of the area of cross section of the sum of the longitudinal bars). However, there are some other important trends in this table. For example, although there are no significant variations in the rigidity of State I, at point Pcr, the crack load increases significantly with As, as it was theoretically demonstrated in a previous publication [32]. Another important aspect is the general idea that the ductility of a structure is related to the ductility of the steel bars. Assuming the dult/dy as an indicator of the ductility of a beam, it appears that a high ductility of the beams could occur with low ductility steel, as that used in this experimental program. As explained before [33; 34], ductility depends on other concrete confinement conditions, which could be much more important. Another important aspect concerns the K\({}_{\text{I}}\)/K\({}_{\text{II}}\) quotient. Eurocode 2, EC2 [35] proposes a value of 3 for this quotient. According to the results obtained for these five cement beams, this quotient can be related to the percentage of reinforcement, \(\rho\), or to the mechanical percentage of reinforcement, \(\omega\), through equations 1. The equations result from an adjustment of the results to an exponential curve (R\({}^{2}\) = 0.98). \begin{table}
\begin{tabular}{c c c c c c c c c c c} \hline \hline \multirow{2}{*}{**Beam**} & \multicolumn{2}{c}{**2F6**} & \multicolumn{2}{c}{**3F6**} & \multicolumn{2}{c}{**4F6**} & \multicolumn{2}{c}{**3F8**} & \multicolumn{2}{c}{**3F8**} \\ \cline{2-11}  & **Cem** & **FA** & **Cem** & **FA** & **Cem** & **FA** & **Cem** & **FA** & **Cem** & **FA** \\ \hline Curing [days] & 34 & 32 & 34 & 32 & 36 & 32 & 37 & 31 & 35 & 31 \\ \hline \(\Delta\)T (min) & 230 & 191 & 146 & 142 & 370 & 147 & 193 & 102 & 219 & 83 \\ \hline Failure by: & As & As & As & As & fc & fc & fc & fc & fc & V \\ \hline \(\Delta\)T = duration of test; As = failure by longitudinal steel bars; fc = failure by crushing of concrete; V—failure by shear (sfirrups). & & & & & & & & \\ \hline \hline \end{tabular}
\end{table} 
Table 4: Further information related with tests.