# Experimental Study on the Flexural Behavior of Alkali Activated Fly Ash Mortar Beams
## 3 Test Results
\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}  & **[PERSON]** & **FA** & **[PERSON]** & **FA** & **[PERSON]** & **FA** & **[PERSON]** & **FA** & **Cem** & **FA** \\ \hline P\({}_{\text{cr}}\) [kN] & 5.73 & – & 7.87 & – & 8.55 & – & 9.47 & – & 10.6 & – \\ \hline d\({}_{\text{cr}}\) [mm] & 0.34 & – & 0.49 & – & 0.60 & – & 0.59 & – & 0.73 & – \\ \hline K\({}_{\text{I}}\) [kN/mm] & 19.7 & – & 17.2 & – & 16.7 & – & 15.9 & – & 16.8 & – \\ \hline P\({}_{\text{y}}\) [kN] & 15.0 & 13.8 & 23 & 19.2 & 29.0 & – & 39.2 & 34.9 & 51.6 & 45.5 \\ \hline d\({}_{\text{y}}\) [mm] & 4.70 & 12.1 & 6.29 & 9.54 & 6.21 & – & 5.68 & 15.3 & 6.42 & 24.3 \\ \hline K\({}_{\text{II}}\) [kN/mm] & 2.50 & 1.36 & 3.48 & 2.25 & 4.27 & – & 5.86 & 2.37 & 7.41 & 1.91 \\ \hline P\({}_{\text{y}}\)/P\({}_{\text{cr}}\) & 2.61 & – & 2.92 & – & 3.40 & – & 4.14 & – & 4.86 & – \\ \hline K\({}_{\text{I}}\)/K\({}_{\text{II}}\) & 7.87 & – & 4.93 & – & 3.83 & – & 2.7 & – & 2.26 & – \\ \hline P\({}_{\text{max}}\) [kN] & 21.0 & 19.7 & 28.8 & 21.5 & 38.9 & \textasciasci{}asci{}asci{}asci{}asci{}asci{}asci{}asci{}asci{}asci{}asci{}asci{}asci{}asci{}asci{}asci{}asci{}asci{}asci{}asci{}asci{}asci{}asci{}{}asci{}asci{}asci{}asci{}asci{}{}asci{}asci{}asci{}asci{}asci{}{}asci{}asci{}asci{}{}asci{}asci{}asci{}{}asci{}asci{}{}asci{}asci{}{}asci{}asci{}{}asci{}asci{}{}asci{}{}asci{}asci{}{}asci{}{}asci{}asci{}{}asci{}{}asci{}{}asci{}{}asci{}{}asci{}{  
Figure 11: P-d curves for beams Cem-3F6 e FA-3F6. Figure 12: P-d curves for beams Cem-4F6 e FA-4F6. Figure 10: P-d curves for beams Cem-2F6 and FA-2F6. In the case of fly ash beams, the discrepancies between the theoretical curves and the experimental curves are more significant. Assuming that the behavior of the steel bars is correct (the reinforcing bars of cement beams were the same as those of fly ash beams), these discrepancies can only be originated from the variability of the mortar material (fly ash), which in fact was confirmed in the laboratory. Beam FA-4F8 was the one that showed the highest degree of initial cracking. In Figure 12, for beam 4F6, there is no experimental curve for the ash beam, as previously mentioned. However, the experimental curves can be presented on the assumption that the fly ash material was similar to the remaining fly ash beams. The curves called \"Theor. 2\" corresponded to the behavior of the beams if the behavior of the material was the one verified in the tests of the \(40\times 40\times 160\) mm prisms, and of the cubes, namely in terms of compressive strength, tensile strength, and modulus of elasticity (as mentioned before, the beams were already cracked before testing). There are important aspects to this prediction. Firstly, for low levels of loading, the curves of the fly ash beams are close to those of the cement beams. In a second aspect, it appears that the beams show lower maximum loads. However, the worse aspect of their behavior when compared to the cement beams, is a very low ductility, since their ultimate load (85% Pmax) occurs for very small deformations (L/dult \(\sim\) 140). For comparison, all the cement beams were at least 5 times more ductile.