## 3 Results  
The study focused on the choice of the most sustainable cement powder to be used for cement bound mixtures (e.g., grouts, mortars, concrete). The four cement powders are identified by the nomenclature _cement_\(n\), with \(n\) varying from 1 to 4, and they are produced by different plants numbered according to the cement nomenclature (i.e., cement 1 is produced by plant 1 or company 1). The hierarchy defined by the authors involves four level of analysis, as represented in Figure 2:  
1. The main goal, the choice of the best cement powder (level I);
2. The objectives of (level II): 1. Minimizing environmental interferences, 2. Minimizing negative social-economic aspects, 3. Maximizing health of workers reducing their job risk;
3. The objectives of (level III): 1. Minimizing impacts on the atmosphere, terrain and water resources (sub-objectives of environment analysis), 2. Minimizing the effects of noise, chemical substances and mechanical vibrations (sub-objectives of workers' health analysis), 3. Minimizing the energy consumption and costs (sub-objectives of socio-economic analysis);
4. The objectives of (level IV): 1. Minimizing global warming potential (_GWP_), ozone depletion potential (_ODP_), and photochemical ozone creation potential (_POCP_) (sub-objectives of atmosphere analysis),* Minimizing eutrophication potential (_EP_) (sub-objective of water environment analysis),
* Minimizing non-hazardous and hazardous waste (sub-objectives of terrain analysis),
* Minimizing exposure to free crystalline silica, Chromium VI and allergizing substances (sub-objectives of chemical risk analysis for workers),
* Minimizing exposure to whole body vibrations and hand-arm vibrations (sub-objectives of mechanical risk analysis for workers),
* Minimizing consumption of renewable resources with energy content, non-renewable resources with energy content, electricity, and water. Figure 2: Hierarchical decomposition used for the analysis. _GWP_: global warming potential; _ODP_: ozone depletion potential; _POPC_: photochemical ozone creation potential; _EP_: eutrophication potential; _nHW_: non-hazardous waste; _HW_: hazardous waste; FCS: free crystalline silica; WBV: whole body vibrations; HAV: hand-arm vibrations; _RRE_: renewable resources with energy content; _nRRE_: non-renewable resources with energy content; _E_: electricity; _W_: water consumption. As regard as the priorities relating to the three criteria of level II, pairwise comparisons gave the results shown in Table 5. Thirty two (32) technicians have participated in the AHP analysis: eight environmental engineers, eight chemical engineers, eight occupational physicians, and eight energy managers. The geometric mean has been used to aggregate individual judgements and obtain pairwise comparison matrices. Values of \(c_{ij}\) show little preference for workers' health respect to environment and society, consistently with the main goal of \"sustainability\". Each element \(c_{ij}\) derives from application of the [PERSON] method [36]: it represents the importance relationships between each pair of criteria. Pairwise comparison matrix for level II (C\({}_{\text{{II}}}\)) has been normalized. Each element \(x_{ij}\) of the normalized pairwise comparison matrix for level II (N\({}_{\text{{II}}}\)) is obtained by dividing each element \(c_{ij}\) by the sum of each column of pairwise comparison matrix (Equation (2)):  
\[x_{ij}=\frac{C_{ij}}{\sum_{j=1}^{n}C_{ij}} \tag{2}\]  
Table 6 represents the normalized pairwise comparison matrix (N\({}_{\text{{II}}}\)) for level II. Table 6 allowed the calculation of weights to be related to each criterion of level II.