## 2 Materials and Methods
### Tests Conducted  
The chemical composition of all materials was determined by X-ray fluorescence analysis using a XEPOS Ametek spectrophotometer (Spectro, Kleve, Germany). Structural characterization of the raw materials was performed with the X-ray diffraction (XRD) technique in a Bruker D8 Advance diffractometer (Bruker, Ettlingen, Germany) with Cu K\(\alpha\) radiation at 40 kV and 40 mA. Crystalline phases were identified by comparison with the JCPDS patterns. Fourier transform infrared spectroscopy (FTIR) of samples was performed by the Perkin Elmer Spectrum 100 FTIR spectrometer in transmittance mode in the range of 400-4000 cm\({}^{-1}\) by attenuated total reflectance (ATR) of the powders (Perkin Elmer Inc., Waltham, MA, USA). The pozzolanic activity of the different wastes was assessed with an accelerated chemical method based on the pozzolanicity test for pozzolanic cements recommended in the European legislation [22]. The saturated lime solution (SLS) test was used, which involved placing 1 g of sample in 75 mL of a saturated lime solution (SLS) at 40 \({}^{\circ}\)C for a pre-established test time. After the reaction time elapsed, the solutions were filtered, and 0.02 M EDTA was titrated to determine its CaO concentration. The amount (%) of lime fixed to the mineral or engineered feldspar was then calculated as the difference between the reference concentration (17.68 mmol/L) and the concentration in the last solution. The Fratini test, found in the European regulations (EN 196-5 standard) for pozzolanic cements [23; 24], was used to assess the pozzolanicity of the studied systems. It consisted of comparing the concentration of lime in a solution containing cement with the different added percentages of the incorporated residue. In this case, as the main difference with the SLS test, the pozzolanicity test for pozzolanic cements in contact with distilled water was evaluated. Pozzolanic cements are a consequence of the incorporation of feldspar in the partial replacement of cement. The methodology was as follows. Twenty grams of the material was mixed with 100 mL of distilled and decarbonated water. The mixture was stirred vigorously to homogenize as much material as possible and kept in an oven at 40 \({}^{\circ}\)C. The test ages included in the regulations were 8 and 15 days. After the reaction periods, the filtered solution was analogously compared to the method used to determine the pozzolanic activity by SLS. \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline \multirow{2}{*}{**System**} & \multirow{2}{*}{**Name**} & \multirow{2}{*}{**Waste**} & **wt \% of** & **wt \% of** & **Activator** & **L/S** \\  & & & **CEM 1** & & **Waste** & \\ \hline Portland cement & CEM I & - & 100 & 0 & H\({}_{2}\)O & 0.50 \\ \hline Alkali-activated & AAS-N & Slag & 0 & 100 & 4M NaOH & 0.50 \\ materials & AAS-WG & Slag & 0 & 100 & Waterglass & 0.50 \\ \hline  & HFA-3\% & Fly ash & 20 & 80 & H\({}_{2}\)O + & 0.37 \\  & HFA-5\% & Fly ash & 20 & 80 & H\({}_{2}\)O + & 0.37 \\ Hybrid & HS-3\% & Slag & 20 & 80 & H\({}_{2}\)O + & 0.42 \\  & HS-5\% & Slag & 20 & 80 & H\({}_{2}\)O + & 0.42 \\  & HWT-5\% & Porous waste & 20 & 80 & H\({}_{2}\)O + & 0.42 \\  & HPT-5\% & Porcelain waste & 20 & 80 & H\({}_{2}\)O + & 0.42 \\  & HPT-5\% & Porcelain waste & 20 & 80 & H\({}_{2}\)O + & 0.37 \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Prepared mortars and activation conditions. Mechanical behavior was determined in mortars with a MICROTEST universal testing machine (Microtest, Madrid, Spain). Three samples of each mortar were measured at different curing ages. Total density was found with gas displacement with a ACCUPYC 1330 helium pycnometer (Micromerities, Norcross, GA, USA). The Bohme machine (Ibertest, Madrid, Spain) test was used to perform the abrasive test on the mortars in accordance with the UNE-EN 13892-3 standard. The tests were performed at room temperature. Brown fused alumina (Al\({}_{2}\)O\({}_{3}\)) was used as an abrasive material, and the applied load was 294 N. Three samples of each mortar were tested.