## 3 Results and Discussion
### Durability to Wear: Bolme Test  
The reactivity (pozzolanicity) of the studied materials exerts an important effect on the formation of gels, thus leading to the evaluated porosities and mechanical strength. Moreover, they are important in understanding the abrasion performance of the proposed alkali-activated materials and hybrid systems after 28 days of curing. Figure 5a,b shows the height and volume losses of each system, respectively, evaluated after the wear test of mortars at the age of 28 days. Results from the Bohme tests are usually evaluated according to height loss (Figure 5a). It is worth highlighting the behavior of AAS-WG, with about half of the height loss than CEM I. This excellent performance can be clearly understood, taking into account the highest strength and lowest porosity of AAS-WG (Figure 4). Moreover, the other alkali-activated material  
(AAS-N) and hybrid materials manufactured from slag (HS-3% and HS-5%) also lost less height than CEM I. These materials are slightly less strong, and their porosity is similar to CEM I (Figure 4). However, the positive compactness of their gels (C-S-H and C-A-S-H) seems to play an important role in the adhesion of sand particles and on the performance of these materials. Hybrid materials with fly ash and ceramic wastes lost more thickness than CEM I, probably related to their higher porosity and less strength (Figure 4) due to the previously explained lack of formation of N-A-S-H gel. From the results of the mass loss and density of each mortar (Table 4), the volume loss of each system after the wear test was also calculated, highlighting the results in Figure 5b. There are slight changes in the trends in comparison to those observed for height loss (Figure 5a). Difference between both measurements can be mainly related to the detachment of sand particles, which affect mass loss more than height. The fact that the abrasion performance of AAS-N worsens can be related to the lower adhesion of sand particles to the C-A-S-H gel than to C-S-H of CEM I. This effect can also be appreciated in AAS-WG. The excellent results of AAS-WG agree with the positive effect of using sodium silicate as an activator found in the literature, being able to promote better abrasion resistances than CEM I Portland cement [30], which does not occur with other activators such as NaOH. Both slag-containing hybrid mortars show improved results of volume loss compared to height, where CEM I is taken as a reference for analysis. This indicates that the positive effect of both gels and using 5% of Na\({}_{2}\)SO\({}_{4}\) promotes the best results (wear improvement was around 42% compared to the CEM I system) as the compactness of the gel is improved (previously found in other properties, Figure 4). In addition, observing the results obtained on porosities, a clear relationship between these parameters is presented since, in general, materials with higher porosities have shown greater volume losses [20]. It should be noted that the hybrid mortar with porcelain waste (HPT-5%), though it did not obtain a high mechanical resistance, showed a notable improvement in terms of durability to wear. Porcelain wastes showed a high Na\({}_{2}\)O content compared to the other proposed wastes. This difference, among other factors, causes this residue to present different results in terms of durability behavior. However, on the other hand, it is important to highlight that the alkaline-activated system with NaOH (AAS-N) presented good mechanical behavior, but after the Bohme test, it was among the systems that presented the worst performance. As studied in previous works [20], using alkaline solutions that  
Figure 4: Relationship between compression strength and total porosity at 28 days of curing for all systems evaluated. present efflorescence phenomena means that after wear with a counter material, there is a greater loss of mass and a greater wear mark is generated.