Multivariate Description of FRC Mechanical Performance
Six variables were considered as descriptors of the mechanical performance of each FRC mix: fc, fL, fR1, fR2, fR3 and fR4, all of them expressed in MPa.
After some preliminary analyses, it was observed that this number of variables needed to be reduced in order to correlate the material’s performance with the flexural creep parameters and the level of sustained load applied. A multivariate analysis was carried out in an effort to find a compromise between the reduction of the number of variables and the amount of information unaccounted for.
The Pearson correlation coefficients  between any pair of these six variables are shown in Table 2. Very strong correlations were observed between the residual flexural strength parameters (values between 0.902 and 0.978). On the other hand, the average compressive strength of concrete was practically uncorrelated to these parameters. The relationship between any of these and the limit of proportionality was less clear, as it was found to be slightly correlated to the compressive strength and moderately to the residual flexural strength parameters.