## 3 Results and Discussion
### Overview and Chloride Penetration Resistance Classification  
The comparisons between the \(D_{cl,IT}\) and the \(D_{cl,WDT}\) with the \(D_{cl,RCMT}\) for all the concrete compositions considered in this study are presented in Figure 14. As discussed, regarding the influence of the type of binder (Section 3.1), a higher R2 was obtained between the \(D_{cl}\) from different tests when concretes with FA incorporation were not considered (Figure 14). This confirms the slow-reactive nature of FA. Therefore, excluding concrete with FA, the RCMT performed at 28 days was able to sort concrete with distinct long-term chloride penetration behaviour, for concretes with different types of binder and aggregate. For concretes with high w/b and porous LWA, the trend is diverted from the linear regression line (Figure 14). Therefore, the relation between tests was more adequate  
Figure 12: Penetration parameters \(K_{cr,IT}\) (**a**) and \(K_{cr,WDT}\) (**b**) as a function of w/b (different types of aggregate). Figure 13: Comparison between \(D_{cl,IT}\) (**a**) and \(D_{cl,WDT}\) (**b**) with \(D_{cl,RCMT}\) (different types of aggregate). for concrete with w/b up to 0.45. Additionally, the \(D_{cl,RCMT}\) varied through a wider range (about 25 \(\times\) 10\({}^{-12}\) m\({}^{2}\)/s) than both \(D_{cl,IT}\) and \(D_{cl,WDT}\) (about 10 \(\times\) 10\({}^{-12}\) m\({}^{2}\)/s), indicating a higher sensibility of the RCMT to diffusion coefficient variations caused by different concrete compositions than the IT or the WDT. A higher R\({}^{2}\) was found when the \(D_{cl,RCMT}\) was correlated with the \(K_{cr,IT}\) and the \(K_{cr,WDT}\), as shown in Figure 15. This means that the RCMT was able to distinguish the chloride penetration resistance of concretes with different w/b, types of binder and types of aggregate of very distinct porosity. Comparing Figure 15 with Figure 9, in general, the type of aggregate had less influence on the relation between tests than the type of binder, since the R\({}^{2}\) remained similar. Contrarily to the comparison made with the \(D_{cl,IT}\) and the \(D_{cl,WDT}\) (Figure 14), the \(D_{cl,RCMT}\) varied in a narrower range than the \(K_{cr,IT}\) and the \(K_{cr,WDT}\). Therefore, a small variation of the \(D_{cl,RCMT}\) results in a more relevant change of the \(K_{cr}\). However, as shown in Figure 16a, in a small range, the variability between tests hinders a precise differentiation of concrete performance from the \(D_{cl,RCMT}\). Indeed, despite the reasonable correlation between tests, the concrete performance did not always follow the same trend. For example, concrete with 6%SF and a w/b of 0.55 presented a lower \(D_{cl,RCMT}\) but a higher \(K_{cr,WDT}\) and \(D_{cl,WDT}\) than concrete with a w/b of 0.35 and 30% LF. This is explained by the different exposure and test conditions. Nevertheless, Figure 16b shows a reasonable correlation between the \(K_{cr,IT}\) and the \(K_{cr,WDT}\), which, as mentioned, can be justified by the similar exposure test conditions. Figure 14: Comparison between \(D_{cl,IT}\) (**a**) or \(D_{cl,WDT}\) (**b**) and \(D_{cl,RCMT}\) for all concrete compositions, except those with FA incorporation. Figure 15: Comparison between \(K_{cr,IT}\) (**a**) or \(K_{cr,WDT}\) (**b**) and \(D_{cl,RCMT}\) for all concrete compositions, except those with FA incorporation. As discussed, a small variation of \(D_{cl,RCMT}\) may correspond to a relevant change of the \(K_{cr}\). Therefore, the defined classes overlap in some ranges, so that concretes of different grades may present similar or even an opposite chloride penetration resistance to that suggested from RCMT classes (Figure 17). Nevertheless, the division in various RCMT classes was able to distinguish concretes with significant differences of chloride penetration resistance, based on \(K_{cr}\). Except for FA concrete, the same ranking of concrete chloride penetration resistance obtained from RCMT was generally maintained after performing long-term tests simulating real exposure conditions.