## 3 Results
### Air Void (AV) Investigation  
Based on Table 7, which shows a quantitative ANOVA for pores, it is possible to ensure that CDWG and FA (factors) have a significant influence (95% confidence) on the amount of pores in concrete blocks. There was also an interaction between both factors in pore formation, 17% contribution. Again, FA added to the mortar was found to be the most significant factor contributing to pore formation (78%). \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline
**Factor** & **Degrees of Freedom** & **Sum of Squares** & **Mean of Squares** & **F-Value** & **\(p\)-Value** & **Percent Contribution** \\ \hline CDW granulometry (CDWG) & 2 & 153.4 & 76.7 & 6.66 & 0.0050 & 1 \\ Foam amount (FA) & 3 & 12,308.3 & 4102.8 & 356.19 & 0.0000 & 87 \\ Interaction between CDWG and FA & 6 & 1396.0 & 232.7 & 20.20 & 0.0000 & 10 \\ Error & 24 & 276.4 & 11.5 & & 2 \\ Total & 35 & 14,134.1 & & & 100 \\ \hline \hline \end{tabular}
\end{table} 
Table 6: Water absorption (WA) ANOVA. Figure 6: Water absorption as a function of FA for different CDW granulometries. Results for AV as a function of FA for different CDW granularometries are presented in Figure 7. Specimens constructed with coarse CDW had smaller AV variations, on average. Specimens constructed with fine CDW also showed increases in FA paired with AV increases. As for specimens made with medium and coarse CDW granulometries, an increase of AV for increases in FA from 3.8% to 5.3% was shown. However, AV remained almost constant for FA from 5.3% to 8.1%. It is understood that these variations might be caused by changes in CDW granulometry that interfered significantly with pore formation. The intersection of curves in Figure 7 represents the interaction between factors on AV. Figure 8 presents typical binary images of transversal sections of the 12 specimens in sequence, following the order of Table 2. Average porosity values were: (1) 31%; (2) 51%; (3) 55%; (4) 59%; (5) 48%; (6) 54%; (7) 53%; (8) 47%; (9) 24%; (10) 56%; (11) 54%; and (12) 53%. \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline
**Factor** & **Degrees of Freedom** & **Sum of Squares** & **Mean of Squares** & _F-Value_ & _p-Value_ &
\begin{tabular}{c} **Percent** \\ **Contribution** \\ \end{tabular} \\ \hline CDW granulometry (CDWG) & 2 & 110.21 & 55.11 & 30.87 & 0.0000 & 4 \\ Foam amount (FA) & 3 & 2135.52 & 711.84 & 398.76 & 0.0000 & 78 \\ Interaction between CDWG and FA & 6 & 457.40 & 76.23 & 42.70 & 0.0000 & 17 \\ Error & 24 & 42.84 & 1.79 & & 1 \\ Total & 35 & 2745.97 & & & 100 \\ \hline \hline \end{tabular}
\end{table} 
Table 7: ANOVA for air void (AV). Figure 8: Typical binary images for different mixes. Figure 7: AV as a function of FA for different CDW granulometries. Figure 9 shows cumulative frequency as a function of average pore diameters for different amounts of foam. Figure 9a-c refer to fine, medium, and coarse CDW granulometries, respectively. Results indicate that pore sizes, which are considered to be perfect circles, showed a variation from 20 \(\upmu\)m to 1200 \(\upmu\)m. Based on D10, D50, and D90 (which are used to represent the mean and ranges of particle sizes), it can be stated that there was a slight increase in the diameter of pores when there was an increase in FA from 3.8% to 5.3% (D10--62 \(\upmu\)m to 95 \(\upmu\)m; D50--325 \(\upmu\)m to 395 \(\upmu\)m; D90--383 \(\upmu\)m to 910 \(\upmu\)m), while pore diameter remained almost constant with FA increases from 5.3% to 8.1%. Medium pore sizes were found to be: D10--80 \(\upmu\)m; D50--372 \(\upmu\)m; D90--903 \(\upmu\)m.  
Another aspect with respect to pore sizes that can be noticed is an increase in the average D10 and D50 sizes for increases in DWG granulometry (fine: D10--52 \(\upmu\)m, D50--347 \(\upmu\)m; medium: D10--80 \(\upmu\)m, D50--355 \(\upmu\)m; coarse: D10--98 \(\upmu\)m and D50--379 \(\upmu\)m).