## 3 Results and Discussion
### Compressive Strength
The results obtained for compressive strength are in accordance with those of [PERSON] et al. [46], who studied a foamed cellular concrete containing pozzolanic material. As is known, pozzolanic additions react chemically with the Ca(OH)\({}_{2}\) from the hydration reactions, thereby decreasing the porosity and the connectivity between pores (capillarity) [47] of the concrete, and, over time, increasing its compressive strength and durability against the action of aggressive agents, such as sulfate and chloride ions [48; 49; 50]. Also, the products formed when the cement is hydrated regulate the behavior of the matrices after hydration. Thus, initial mechanical strengths can be high if the cement contains large amounts of C\({}_{3}\)S. However, at more advanced ages the greatest influence on mechanical resistance is given by C\({}_{2}\)S [26]. \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline
**Factor** & \begin{tabular}{c} **Sum of** \\ **Squares** \\ \end{tabular} & \
\begin{tabular}{c} **Degrees of** \\ **Freedom** \\ \end{tabular} &
\begin{tabular}{c} **Mean of** \\ **Squares** \\ \end{tabular} & \(F\)**-Value** & \(p\)**-Value** & \% **Contribution** \\ \hline Cement Type (CT) & 67.697 & 2 & 33.848 & 34.159 & 0.0000 & 13.4 \\ Foam Amount (FA) & 196.517 & 2 & 98.258 & 99.160 & 0.0000 & 39.0 \\ Additive Type (AT) & 5.425 & 3 & 1.808 & 1.825 & 0.1502 & 1.1 \\ CT\({}^{*}\)FA & 67.534 & 4 & 16.883 & 17.038 & 0.0000 & 13.4 \\ CT\({}^{*}\)AT & 18.880 & 6 & 3.147 & 3.176 & 0.0080 & 3.7 \\ FA\({}^{*}\)AT & 49.273 & 6 & 8.212 & 8.288 & 0.0000 & 9.8 \\ CT\({}^{*}\)FA\({}^{*}\)AT & 27.378 & 12 & 2.281 & 2.302 & 0.0151 & 5.4 \\ Error & 71.345 & 72 & 0.991 & & & 14.2 \\ Total & 504.048 & 107 & & & & 100.0 \\ \hline \hline \end{tabular}
\end{table} 
Table 4: Analysis of variance for compressive strength after 28 days of curing. Figure 3: Compressive strength related to (**a**) cement type, (**b**) foam amount, and (**c**) additive type for different curing times, where the middle point is the mean, the box is the confidence interval (95%), and the whisker shows the standard deviation. \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline
**Factor** & \begin{tabular}{c} **Sum of** \\ **Squares** \\ \end{tabular} & \
\begin{tabular}{c} **Degrees of** \\ **Freedom** \\ \end{tabular} &
\begin{tabular}{c} **Mean of** \\ **Squares** \\ \end{tabular} & \(F\)**-Value** & \(p\)**-Value** & \% **Contribution** \\ \hline Cement Type (CT) & 26.618 & 2 & 13.309 & 9.28 & 0.0002 & 2.8 \\ Foam Amount (FA) & 362.858 & 2 & 181.429 & 126.43 & 0.0000 & 37.8 \\ Additive Type (AT) & 86.817 & 3 & 28.939 & 20.17 & 0.0000 & 9.0 \\ CT\({}^{*}\)FA & 69.851 & 4 & 17.463 & 12.17 & 0.0000 & 7.3 \\ CT\({}^{*}\)AT & 114.476 & 6 & 19.079 & 13.30 & 0.0000 & 11.9 \\ FA\({}^{*}\)AT & 68.998 & 6 & 11.500 & 8.01 & 0.0000 & 7.2 \\ CT\({}^{*}\)FA\({}^{*}\)AT & 127.327 & 12 & 10.611 & 7.39 & 0.0000 & 13.3 \\ Error & 103.318 & 72 & 1.435 & & & 10.8 \\ Total & 960.263 & 107 & & & & 100.0 \\ \hline \hline \end{tabular}
\end{table} 
Table 5: Analysis of variance for compressive strength after 365 days of curing. Figure 3b plots the compressive strength with respect to the amount of foam (% of total mass) for different curing times (28 days and 365 days). When increasing the amount of foam the compressive strength decreases. This occurs due to air being incorporated into the foam, as a result of which pores forms in the structure, decreasing the density and, consequently, the compressive strength [22; 23]. Also, the compressive strength increases significantly when the curing time is increased, i.e., an average increase of approximately 40% in compressive strength can be obtained. This increase in compressive strength achieved by increasing the curing time occurs due to the interaction between the factors, especially the interaction between the types of cements and the amount of foam [51]. It is known that pozzolanic additions lead to a late gain in compressive strength, which explains the greater influence of the type of cement at more advanced ages.