# Granular Material Development Applied in an Experimental Section for Civil Engineering Purposes
## 3 Results
### Experimental Section: \"Accumulated\" and \"Punctual\" Rainwater Leachates  
As previously mentioned, the rainwater leachates were collected each time it rained in the area of the experimental section. The collection of the leachates was done on the first not-rainy day. This means that if, for example, on three consecutive days it rained, the leachates were assembled on the fourth day. The rainwater samples were assembled 27 times, after almost 600 days. The following results (Figures 7 and 8a-i) compare the \"accumulate\" and the \"punctual\" leachates, expressing the \"punctual\" as an addition of the concentration of each previous metal(loid) concentration analyzed. This means the \"punctual\" leachates are expressed as an integration of each previous concentration result, in order to compare them with the \"accumulated\" results. \begin{table}
\begin{tabular}{c c c c c c c c c c c c c} \hline  & **Eluates** & **L/S** & **pH** & **k (\(\mu\)S/cm)** & **As** & **Ba** & **Total Cr** & **Cu** & **Hg** & **Mo** & **Ni** & **Pb** & **Zn** \\ \hline \multirow{5}{*}{**WBA**} & **E1** & 0.1 & 11.90 & 26.15 & 0.28 & 1.06 & **28.77** & 28.18 & 0.01 & **10.26** & 0.27 & 1.29 & 1.34 \\  & **E2** & 0. Figure 7 shows the pH results from the \"accumulated\" and \"punctual\" rainwater leachates. As the figure shows, in general, the pH in the \"punctual\" leachates is higher than in the \"accumulated\" ones, due to the saturation of the solution because of the high lime (CaO) content. The pH in the \"accumulated\" leachates is close to the pH controlled by the Ca(OH)\({}_{2}\). Besides, although both types of  
Figure 8: Concentration for both “accumulated” and “punctual” samples (**a**) As, (**b**) Ba, (**c**) Total Cr, (**d**) Cu, (**e**) Hg, (**f**) Mo, (**g**) Ni, (**h**) Pb and (**i**) Zn. leachates have the same L/S ratio (a value of 2), the \"punctual\" pH is higher because, as the surface is higher, the ability to collect rainwater is also higher. Therefore, as the \"accumulated\" area receives more leaching rainwater, it may not have achieved the saturation, or the lime concentration in this surface is lower. It would also be important to consider the evaporation phenomenon as another parameter to consider in the L/S ratio (it is not contemplated in this study). Regarding the \"accumulated\" ones, the pH values were between 7 and 9, although two samples at the beginning of the experimental section were pH > 12. The pH of \"punctual\" samples was more constant, and in general, more alkali (around pH = 12), compared to the \"accumulated\" leachates. This behavior is usual for the M sample, as it is controlled by the CaO solubility of both the APC and OPC binder at a pH around 12. This pH factor is important to consider regarding the release of some metal(loid)s, because some of them are pH-dependent (such as As (III), Cr (III), Cu, Ni, Pb and Zn). The results by means of ICP-MS analysis of each of the analyzed metal(loid)s are presented in Figure 8, considering the concentration of the metal(loid)s before the percolation days. A comparison between the \"accumulated\" and the \"punctual\" leachates is performed. As previously mentioned, the L/S ratio in the experimental section was 2 in both \"accumulated\" and \"punctual\" leachates. Therefore, all the metal(loid)s concentration results are compared with those named E5 in the percolation column tests, as the L/S is 10 in the dynamic leaching tests. Then, it can be expected that, in the real experimental section, when achieving an L/S ratio of 10, the leachates' concentrations will decrease even more. Besides, as the pH in the \"punctual\" leachates is much higher than in the \"accumulated\" ones, the leaching is also higher for the \"punctual\" ones in most of the cases. In Figure 8a is presented the As concentration results.