# Characterization and Reactivity of Natural Pozzolans from Guatema
## 3 Results and Discussion
### Pozzolanic Activity  
#### 3.2.1 Electrical Conductivity Test  
During the electrical conductivity test, suspensions were continuously shaken inside a thermal bath to facilitate the pozzolanic reaction process. Flasks were covered with parafilm paper to avoid carbonation and water loss by evaporation. Data collection was performed at 0 h, 0.5 h, 4 h, 8 h, and 24 h, and then every day for 6 more days.  
The values of electrical conductivity and the [OH\({}^{-}\)] concentration of the samples tested at 60 \({}^{\circ}\)C for the 3.0:7.0 and 0.5:9.5 lime ratios of sample T are shown in Figure 5. For the 3.0:7.0 sample, no significant change was observed in the curves of the electrical conductivity and [OH\({}^{-}\)] concentration (the suspension was saturated in calcium hydroxide). A considerable change in the conductivity and [OH\({}^{-}\)] concentration curves for the 0.5:9.5 sample occurred on the first test days, which demonstrates that the suspension was unsaturated.  
Figure 4: X-ray diffractograms of T and R.  
The comparison of these two mixtures is represented in terms of loss of electrical conductivity in Figure 6, which was calculated according to [25].  
Figure 5: Electrical conductivity and [OH\({}^{-}\)] concentration measurements for sample T at 60 \({}^{\circ}\)C: (a) 3:7 and (b) 0.5:9.5 lime:pozzolan ratios (Sample T).  
Figure 6: Loss of electrical conductivity for sample T at 60 \({}^{\circ}\)C.  
The loss of electrical conductivity showed a much better comparison among suspensions. The sample with the 0.5:9.5 ratio displayed significant conductivity loss because of the achieved unsaturation, while there was no significant loss for the 3:7 ratio. Hence, it was continuously saturated in Ca(OH)\({}_{2}\). According to [PERSON] et al., suspensions whose electrical conductivity loss is over 30% (\(L_{c}\) = 30%) correspond to solutions that are unsaturated in calcium hydroxide [25].  
The conductivity loss percentage was calculated according to Equations (1) and (2):  
\[L_{c}(\%)=\frac{C_{o}-C_{i}}{C_{o}}*100 \tag{1}\]  
\[C_{i}=C_{t}-C_{puz} \tag{2}\]  
\(C_{o}\):Initial electrical conductivity of the calcium hydroxide suspension before adding pozzolan; \(C_{t}\):Electrical conductivity value measured in the CH/P suspension at time \(t\); \(C_{puz}\):Electrical conductivity of the water/pozzolan suspension (0.0:10.0 mixture).  
It should be noted that, throughout the experiment, the \(C_{puz}\) values never exceeded 1 mS/cm. Hence, the conductivity loss correction was negligible and allowed the \(C_{i}\) and \(C_{t}\) values to be analogous.  
According to Figure 7, the suspensions with excess calcium hydroxide did not exhibit significant changes in electrical conductivity loss. These values remained practically constant throughout testing. Significant variation appeared in the suspensions that reached unsaturation, which were 2.0:8.0; 1.5:8.5; 1.0:9.0, and 0.5:9.5. In the saturated suspensions, they were 3.0:7.0 and 2.5:7.5, and remained so throughout testing. The electrical conductivity loss data are summarized in Table 5 for the 60 \({}^{\circ}\)C temperature after 7 days to compare samples T and R.  
According to [PERSON]. [PERSON] et al. [25], samples R and T can be classified as low-reactivity pozzolanic materials.