## 3 Results and Discussion  
### Fresh Properties  
The self-compacting properties of the concretes were determined according to the standards set by [28; 29; 30]. The fluidity of the concretes was measured using the slump flow test based on the flow measurements. According to [28], concretes can be classified by their flow as SF1 (between 550 and 650 mm), SF2 (between 660 and 750 mm), or SF3 (between 760 and 850 mm), with each class having a specific application. As shown in Figure 5, the SCLC-EC and SCLC-SBA50 concretes were classified as SF2, suitable for most reinforced concrete applications, while the SCLC-SBA90 and SCLC-SMR37 concretes were classified as SF1, recommended for structures with low reinforcement rates, self-compacting concretes that require pumping, and/or structures that demand little horizontal flow. The difference in flow between SCLC-EC and the other concretes can be attributed to the low density of the expanded clay aggregate and its vitreous surface, resulting in easier flow of the cementitious matrix due to the rolling action of the aggregates [17]. Similarly, although the aggregate in SCLC-SBA90 had a higher density than the aggregate in SCLC-SMR37, the greater flow of SCLC-SBA90 can be explained by its water absorption. The [35] states that ideal water absorption values for lightweight aggregates typically range from 5% to 25%. Thus, while the SBA90 aggregate had a water absorption of 15%, which facilitated better homogenization between the aggregate and the cementitious matrix and was closer to the expanded clay's absorption of 14%, the SMR37 aggregate had a water absorption rate of 2.5%, which made it more difficult to bond quickly with the cement paste. Figure 5: Flow of the concretes studied. In Figure 6, the results of the flow time test (T500), which measured the apparent viscosity of the concrete, are presented. Apparent viscosity is related to the consistency of the mixture and directly influences the concrete's resistance to flow. According to the results, all the concretes were classified as VS2, making them suitable for most common applications. This classification also indicates a thixotropic effect, meaning the concrete exerted less pressure on the forms and had improved resistance to segregation, as per the definitions established by [28]. In agreement with [PERSON] et al. [21], Figure 7 shows a relationship between the increase in fine aggregate consumption and the viscosity of the concretes. As the amount of sand in the mixture increased, the flow time also increased, a result of the density differences between the aggregates and the cementitious matrix [27; 28]. Figure 6: Apparent viscosity of the concretes in the T500 test. Figure 7: Relationship between fine aggregate consumption and the viscosity of the concretes. In [PERSON] et al. [29], it was observed that, despite the concretes having the same viscosity classification, mixtures with higher amounts of mineral additions, particularly metakaolin, exhibited higher viscosity values. In the present study, although the amount of metakaolin was the same for all mixes, a directly proportional relationship between the increase in viscosity and the amount of fines in the mixture was noted. Additionally, [PERSON] et al. [30] and [PERSON] [23], found an inverse relationship between the volumetric amount of lightweight aggregates and flow time in their studies. However, in the results obtained in this study, the opposite was observed: increasing the amount of aggregates in the mix increased the flow time. This behaviour was consistent across all mixtures, except for SCLC-SMR37, which can be explained by the low absorption rate of the aggregates that prevented complete homogenization with the matrix. Figure 8 illustrates the behaviour of the concretes during the slump flow test, which provided the visual stability index. This qualitative parameter evaluated concrete's resistance to segregation and/or bleeding.