## 3 Results and Discussion
### Influence of the Type of Aggregate on the Chloride Penetration Resistance  
The variation of the \(D_{d,RCMT}\) with the w/b for NWC and LWAC is presented in Figure 10. Although aggregates with very distinct porosities were considered, the \(D_{d,RCMT}\) was affected little by the type of aggregate. For concretes with similar composition, the maximum variability was lower than 15%, which is under the maximum variability reported for this test [5]. The low influence of the type of LWA was also found by other authors, concluding that the chloride penetration resistance is mainly influenced by the paste quality [10; 54; 55; 56]. However, LWAC with more porous LWA (Leca) showed slightly higher \(D_{cl,RCMT}\) for all w/b. This may be related with the greater participation of LWA when saturated concrete is tested and chloride ions are allowed to migrate through continuous passes [39; 74]. On the other hand, when concretes are allowed to dry and LWA are emptied by internal curing, their participation in chloride migration is decreased, especially in low w/b concrete, where the aggregates are protected by a denser paste [54]. However, since the RCMT is performed in cut specimens, aggregates near the surface are more easily accessed and penetration becomes more relevant. In fact, in Figure 11, the participation of Leca in high w/b concrete seems to have been slightly higher than in low w/b concrete. Nevertheless, according to the classification of Gjerv [33] (Table 1), the chloride penetration resistance of LWAC was comparable to that of NWC, being considered as concrete of moderate quality for w/b up to 0.45. The classification of Gjerv [33] was not able to distinguish the worse quality of LWAC with more porous aggregates in high w/b concretes (Table 5). However, concretes with w/b over 0.55 are not common in chloride exposure environments. Figure 11: Chloride diffusion coefficient, \(D_{d,IT}\) (**a**) and \(D_{d,WDT}\) (**b**) as a function of w/b (different types of aggregates). Figure 10: Chloride migration coefficient at 28 days, \(D_{cl,RCMT}\), as a function of w/b. The results of the \(D_{d,II}\) and the \(D_{d,WDT}\) taking into account different types of aggregates are presented in Figure 11. Contrary to other studies [52; 53; 54], the \(D_{d}\) was affected by the type of aggregate. In this case, LWAC with porous LWA always led to higher \(D_{d}\), confirming the trend of the RCMT. This behaviour was more markedly observed in the IT (Figure 11a), because as discussed, if concretes are saturated the participation of porous aggregates becomes more evident, especially in high w/b concrete. In fact, in these IT, concrete was kept saturated since their production, reducing the opportunity of LWA to release their water by internal curing. In this case, the high w/b imply less dense pastes surrounding LWA and also a lower relevance of self-desiccation, and, hence, of the activation of the internal curing mechanism. Moreover, in high w/b concretes, LWA near the concrete surface are easily saturated by water permeability, which allow their participation in chloride diffusion. This phenomenon is more relevant in the present study, because penetration occurred perpendicular to the casting surface, where surface LWA were less protected by a mortar layer. The obtained results corroborate the study of [PERSON] et al. [39], concerning the monitorisation of different types of concrete exposed to real marine environment for 5 years. The authors found a lower chloride penetration resistance of LWAC than of NWC, during the first months of exposure, but the difference tended to be diluted over time, when inner concrete at greater depths were progressively involved. This is also in line with the results reported by [PERSON] and [PERSON] [73], indicating that LWAC and NWC presented similar chloride resistance, after 25 years of exposure to harsh marine environment. In opposition, during the WDT, the concrete surface was allowed to dry, which promoted the partial emptying of the LWA.