## 3 Test Results
### Rupture of Cylindrical Specimens  
After completion of the modulus of elasticity tests, the compression tests were performed on the last 3 specimens. For this purpose, an AMSLER compression machine with a capacity of 500 tons was used.  
Table 6 shows the following data: the age of the sample at the time of testing; the compressive strength \(\sigma_{\mathrm{c1}}\) (Table 4); the corresponding value for cylindrical samples \(\sigma_{\mathrm{c2}}\); the modulus of elasticity E\({}_{2}\), previously determined; the effective load ratio in this test V; the time interval for loading \(\Delta\)T; the measured strain at rupture \(\varepsilon_{\mathrm{max}}\); the maximum force F\({}_{\mathrm{c}}\) measured in this compression test; the corresponding compressive strength \(\sigma_{\mathrm{c3}}\); the ratio \(\sigma_{\mathrm{c3}}/\sigma_{\mathrm{c2}}\); the modulus of elasticity E\({}_{31}\), measured up to 40% of the compressive strength; the ratio E\({}_{31}\)/E\({}_{2}\); and the secant modulus of elasticity E\({}_{32}\), measured up to 60% of the compressive strength and up to 80% E\({}_{33}\). The \(\sigma_{\mathrm{c2}}\) value was estimated from \(\sigma_{\mathrm{c1}}\) using [PERSON]'s [27] suggestions. Namely, [PERSON] suggests that the compressive strength of a 40 mm cube is about 10% greater than that of a 150 mm cube, and that the compressive strength of a cylinder is 80% of the corresponding value of a 150 mm cube.  
It should be noted that the load ratio of the MN sample was excessive. The higher values of the modulus of elasticity can be explained by that. Furthermore, in the record  
\begin{table}
\begin{tabular}{c c c c} \hline \hline
**Sample** & **MW2** & **MC** & **MN** \\ \hline Age [h] & 839 & 669 & 501 \\ \(\sigma_{\mathrm{c1}}\) [MPa] (40 mm \(\times\) 40 mm) & 35.1 & 36.3 & 35.5 \\ \(\sigma_{\mathrm{c2}}\) [MPa] (cylinder \(\phi\) = 107 mm) & 25.5 & 26.4 & 25.8 \\ E\({}_{\mathrm{2}}\) [GPa] & 17.3 & 19.5 & 18.2 \\ V [MPa/s] & 0.226 & 1.18 & 3.35 \\ \(\Delta\)T & 90 & 21 & 12 \\ \(\varepsilon_{\mathrm{max}}\) [\%] & 1.67 & 1.70 & 1.37 \\ Fc [KN] & 229 & 183 & 216 \\ \(\sigma_{\mathrm{c3}}\) [MPa] (actual) & 25.5 & 20.4 & 24.1 \\ \(\sigma_{\mathrm{c3}}\) / \(\sigma_{\mathrm{c2}}\) & 100\% & 77.2\% & 93.2\% \\ E\({}_{\mathrm{31}}\) [GPa] (actual) & 17.1 & 17.9 & 19.6 \\ E\({}_{\mathrm{31}}\) / E\({}_{\mathrm{2}}\) & 99\% & 92\% & 108\% \\ E\({}_{\mathrm{32}}\) [GPa] & 16.5 & 12.9 & 18.8 \\ E\({}_{\mathrm{33}}\) [GPa] & 15.6 & – & 17.2 \\ \hline \hline \end{tabular}
\end{table}
Table 6: Rupture of cylinder tests.  
Figure 12: Average values of the modulus of elasticity. MN sample.  
speed (1 Hz), the values before the maximum stress moment recorded, were a lesser amount of 2.9 MPa (stress) and 0.3% (strain). So, the lower values shown (\(\varepsilon_{\text{max}}\) and \(\sigma_{\text{c3}}\)) can definitely be explained by load ratio.  
For the MC sample, the results show the existence of prior ruptures. This is the conclusion that it is possible to draw from the lower values of \(\sigma_{\text{c2}}\), E\({}_{\text{31}}\), and E\({}_{\text{32}}\). With reference to Figure 11, it is now easy to see the E\({}_{\text{2}}\) reduction in the latest tests.  
Regarding the strain recorded at rupture: taking it as a comparative term, the assumed strain for the concrete (2%), in this case, is a little below this value. The secant modulus of elasticity (E\({}_{\text{32}}\) and E\({}_{\text{33}}\)) is another parameter for recording assurances. In fact, these values indicate an almost linear behavior, until rupture.  
The rupture was due to longitudinal cracks of the samples (Figure 13). Probably due to fatigue caused by loading/unloading cycles to which they have been subjected. It should be noted that the total number (\(\sim\)20) of tests was similar for all samples, with corresponding maximum stresses (between 0.8 MPa and 5.6 MPa). The only difference is that the MC sample was subjected to a higher number of tests in the first 100 h.