## 2 Materials and Methods
The calcium-containing phases were dissolved in the SAM medium after the attack, while phases without calcium remained in the insoluble residue. The SAM extraction procedure consisted of mixing 1 g of grounded sample with salicylic acid (6 g) and methanol (40 mL) for 1 h. The mixture was subsequently filtered (Whatman filter with 20 \(\upmu\)m pore size) to obtain the insoluble residue. The HCl extraction consisted of stirring 1 g of AA-WBA binder with 250 mL of HCl (1:20) solution for 3 h, followed by filtration (Whatman filter with 20 \(\upmu\)m pore size). Then, the insoluble residues were washed with deionized water and dried in a desiccator until reaching a constant weight. The percentage of weight loss due to SAM and HCl extraction was calculated by weighing the insoluble residue. XRD analysis was performed to determine the crystalline phases of AA-WBA binders. FTIR was used to determine the reaction products of alkali-activated WBA by means of various Si-O-X (X=Al, Si) stretching peaks' identification, which are assigned to different chemical structures of silicate \begin{table}
\begin{tabular}{l c c c c c c} \hline \hline  & \multicolumn{6}{c}{**L**} \\ \cline{2-7}
**Reference** & \multicolumn{3}{c}{**1 NaOH (wt.\%)**} & \\ \cline{2-7}
**2M** & **4M** & **6M** & **8M** & **1 Na\({}_{2}\)SiO\({}_{3}\) (wt.\%)** & **1 Na\({}_{2}\)O (wt.\%)** & **2 SiO\({}_{2}\)/Na\({}_{2}\)O** \\ \hline AA-WBA-2M & 20 & & & 80 & 7.7 & 3.6 \\ AA-WBA-4M & 20 & & & 80 & 8.7 & 3.2 \\ AA-WBA-6M & & 20 & & 80 & 9.7 & 2.9 \\ AA-WBA-8M & & & 20 & 80 & 10.7 & 2.6 \\ \hline \hline \end{tabular}  
* With respect to the WBA content. 2
* Molar ratio.  
\end{table} 
Table 2: Alkali-activator solution proportions and chemical composition. phases. Spectrum Two(tm) equipment from Perkin Elmer was used. The insoluble residue obtained in SAM and HCl extraction was also analyzed by FTIR to identify possible changes in the AA-WBA binders' composition and elucidate the co-existence of both C-(A)-S-H and N-A-S-H gels. A scanning electron microscopy (SEM) technique was conducted by an ESEM FEI Quanta 200 to evaluate the AA-WBA binders' microstructure. A planar sample (1.5 mm thickness) of each formulation was obtained by means of a diamond disc (140 rpm) cutter, and coated with graphite. Bulk density and open porosity were studied by using 3 cubic shape specimens for each formulation. The values were determined following the standard EN 1936:2006. After 28 curing days of the AA-WBA specimens, compressive strength (\(\sigma_{c}\)) tests were performed using Incotencic MULTI-R1 equipment. Three tests were performed for each formulation. A progressive load until fracture was applied with a loading rate of 240 kg-s\({}^{-1}\). Leaching tests in deionized water for 24 h were conducted according to European standard EN 12457-2 to evaluate the potential release of heavy metal(loid)s from WBA and AA-WBA binders. A PerkinElmer ELAN 6000 ICP mass spectrometry (ICP-MS) device was used to analyze heavy metal(loid)s (As, Ba, Cd, Cr, Cu, Hg, Mo, Pb, Ni, Sb, and Zn) in the obtained eluates. The cost of AA-WBA binders (\(\epsilon\)t\({}^{-1}\)) considering the cost of the raw materials (Table 3) used for their formulation was calculated.