## 4 Conclusions  
The valorization of the WBA is a challenge to be solved by the WtE plants due to the continuous growth of MSW around the world. The work reported herein validates the potential of WBA as precursor in alkali-activated cements. The use of WBA as precursor promotes the zero-waste principle and contributes to the development of new low-carbon cements. Moreover, the novelty and uniqueness of this research was based on reducing the curing temperature of the AA-WBA. The curing at room temperature allowed for the extension and facilitation of the applicability of the AACs. The hydrolytic stability and integrity tests demonstrated that AA-WBA were properly bonded. Selective chemical extraction and physicochemical characterization revealed the formation of C-(A)-S-H gel in the AA-WBA. It also proved the influence of the alkali-activator concentration in their microstructure. The selective chemical extraction and physical characterization results were in accordance with the compressive strength results, where it was demonstrated that the use of AA-WBA is only for non-structural purposes. Environmental characterization showed a concerning activation of As and Sb, which entails a setback for the waste management of the material once its cycle of life is finalized. The cost of the AA-WBA formulations demonstrate that it is not possible to compete with OPC in economic terms due to the high cost of sodium silicate. It would be necessary to search alternatives to produce a sodium silicate from waste glass, making AA-WBA binders more economical and sustainable.  
The authors will focus their future line investigation on the formulation of AA-WBA using the least polluted fractions of WBA (coarser fractions). The main aim is using fractions that contain greater availability of SiO\({}_{2}\), hence favoring the formation of C-(A)-S-H and N-A-S-H gels to enhance the mechanical properties of AA-WBA. The environmental properties of AA-WBA binders would also improve given the low content of heavy metal(loid)s in coarse fractions.  
Conceptualization, J.M.C. and J.G.-P.; methodology, A.M.-A. and A.A.-R.; validation, J.G.-P., J.F., and J.M.C.; formal analysis, A.M.-A.; investigation, A.M.-A. and [PERSON]; data curation, J.F.; writing--original draft preparation, A.M.-A.; writing--review and editing, [PERSON], J.F., and J.M.C.; supervision, J.M.C. and [PERSON]; funding acquisition, J.M.C. All authors have read and agreed to the published version of the manuscript.  
This research was funded by the Spanish Government (BIA2017-83912-C2-1-R). The authors would like to thank the Catalan Government for the quality accreditation given to their research groups DIOPMA (2017 SGR 118). The authors also want to thank SIRUSA and VECSA for supplying MSWI Bottom Ash and [PERSON] for the linguistic revision. [PERSON] is grateful to the Government of Catalonia for the research Grant (FI-DGR 2017).  
The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.  
\begin{table}
\begin{tabular}{c c c c c} \hline \hline
**OPC** & **AA-WBA-2M** & **AA-WBA-4M** & **AA-WBA-6M** & **AA-WBA-8M** \\ \hline
106.2 [61] & 137.6 & 143.3 & 148.8 & 153.9 \\ \hline \hline \end{tabular}
\end{table}
Table 6: Cost (€\(\cdot\)t\({}^{-1}\) binder) of AA-WBA formulations.