## 3 Experimental Results
### Beam Performance
Figure 8: Graphical representation of the probabilistic density function (PDF) obtained from the simulation results together with the values obtained from the experimental tests of the six beams (B1–B6): (**a**) maximum load; and (**b**) deflection. The behaviour of all tested beams is within the PDF obtained from the simulation. For the case of the maximum load, the experimental results are close to the modal value. Only beams B3 and B4 are slightly further away from this central value. In the case of deflection, the experimental results are further apart and in all cases exceed the modal value of deflection. One of the reasons for this greater dispersion is the greater number of probabilistic parameters involved in this simulation. In addition, the difficulty of predicting deflection in reinforced concrete is greater because parameters such as the effective moment of inertia or the moment to cause cracking are less accurately estimated. Even some factors such as creep or shrinkage are not taken into account in the theoretical analytical models for calculating deflection. In any case, all the results were within the range predicted by the reliability analysis, so it can be assumed that the model is valid and reliable. From the reliability analysis and the probability of failure corresponding to each load and deflection, the percentile in which the behaviour of each beam is located was calculated. The results of the maximum load and deflection of each beam, together with their corresponding, are shown in Table 3.  
The following criteria were used to calculate the percentiles: higher maximum load values correspond to better behaviour and lower percentiles; higher deflection values correspond to worse behaviour and higher percentiles. The results obtained in calculating the percentiles allow us to quantify the above for the behaviour of the experimental tests. The experimental results for maximum load show percentiles close to the mean, except for specimen B4, which is in the last decile. The experimental deflection results show higher percentiles, mostly in the last quartile. It should be noted that the analytical models used did not include safety coefficients, so it is understandable that the results are not in the first percentiles. Other factors other than the main properties obtained experimentally, such as creep or shrinkage deformation, which should be taken into account to improve the accuracy of the model, were also not included. In addition, all the tests were within an acceptable range, as none of them exceeded what could be considered a limit of 5%. In order to understand which variables are most relevant in the theoretical analytical performance model of recycled concrete, a Sobol sensitivity analysis was carried out. As the prediction of deflection was the most complex model with the most variables and the most dispersed behaviour, the analysis was performed on this model. The same analytical model used for the reliability-based design analysis was employed, with input variables including the compressive strength, tensile strength, and modulus of elasticity of the recycled concrete, as well as the coefficient for calculating the effective moment of inertia. Similarly, the variability of these parameters was introduced by means of their corresponding PDF. In order to carry out this sensitivity analysis, a total of \(10^{6}\) simulations were carried out using MCS. For each of these simulations, the input parameters were given a random value based on the distributions and ranges obtained in the experimental tests. The variances of the input parameters were analysed with respect to the variance of the model outputs, which allowed Sobol indices to be obtained. The results of this analysis