## 3 Results and Discussion
### Fresh-State Properties of the Mortars
#### 3.1.2 Air Content and Density  
The results of air content and fresh-state density of the analysed mixes are shown in Table 4. The incorporation of 5% and 10% of RC (mixes M-5/0 and M-10/0) leads to an increase of 18.8% and 37.5% of air content, respectively, compared to the conventional mix, due to a greater porosity of the adhered mortar and to a more irregular shape of the RC particles compared to the OPC particles (Figure 2). The incorporation of 10% and 20% of FA (mixes M-0/10 and M-0/10) leads to a decrease between 37.5% and 50.0%, respectively, of air content with respect to the conventional mix, due to a more spherical shape and smoother surface of FA particles compared to OPC particles. Likewise, the simultaneous incorporation of RC and FA (mixes M-5/10 and M-10/20) produces a decrease in air content of 31.3% and 56.6%, respectively, compared to the conventional mortar. This behaviour may be due to a possible filling effect of FA particles in the RC. Figure 3a shows the decreasing linear variation (R\({}^{2}\geq\) 0.83) between air content and consistency, highlighting the high linear correlation between these properties.  
The incorporation of RC, FA, and the joint incorporation of RC and FA leads to slight (linear) decreases (R\({}^{2}\geq\) 0.92) of density, regardless of the type of waste considered (Figure 3b), due to the lower density of these additions with respect to the OPC (Table 2). Likewise, these decreases do not exceed 2% and all the values of density were within the normal range (2200-2250 kg/m\({}^{3}\)) for FA and for RC that replace cement [35; 36].  
Finally, the simultaneous incorporation of RC and FA leads to a higher fresh-state density of mortars with respect to their binary counterparts (RC or FA). This effect may be mainly due to the filling effect of the FA particles in the voids of the RC particles, resulting in denser cementitious matrices. These observations are in line with the findings of [PERSON] et al. [37] for ternary mortars made with limestone powder and FA.  
\begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline
**Parameter** & **RM 1** & **M-5/0** & **M-10/0** & **M-0/10** & **M-0/20** & **M-5/10** & **M-10/20** \\ \hline Consistency (mm) & 271 & 268 & 260 & 292 & 319 & 284 & 301 \\ Air content (vol\%) & 1.6 & 1.9 & 2.2 & 1.0 & 0.8 & 1.1 & 0.7 \\ Density (kg/m\({}^{3}\)) & 2249 & 2221 & 2213 & 2230 & 2203 & 2227 & 2214 \\ \hline
**Differential** & \multicolumn{3}{c}{\(\Delta\) **with RC (\%) 2**} & \multicolumn{3}{c}{\(\Delta\) **with FA (\%) 3**} & \multicolumn{3}{c}{\(\Delta\) **with RC \(\times\) FA (\%) 4**} \\ \hline Consistency (mm) & - & \(-\)1.1 & \(-\)4.1 & 7.7 & 17.7 & 4.8 & 11.1 \\ Air content (vol\%) & - & 18.8 & 37.5 & \(-\)37.5 & \(-\)50.0 & \(-\)31.3 & \(-\)56.3 \\ Density (kg/m\({}^{3}\)) & - & \(-\)1.2 & \(-\)1.6 & \(-\)0.8 & \(-\)2.0 & \(-\)1.0 & \(-\)1.4 \\ \hline \hline \end{tabular} Notes: 1 RM: reference mortar; 2 \(\Delta\) with RC (%) compares RM to M-5/0 and to M-10/0, 3 \(\Delta\) with FA (%) compares RM to M-0/10 and to M-0/20, and 4 \(\Delta\) with RC \(\times\) FA (%): compares RM to M-5/10 and to M-10/20.  
\end{table}
Table 4: Fresh-state properties of the studied mortars.