## 3 Material Characterization and Concrete Compositions  
The raw materials chosen to produce concrete mixes include: fine natural aggregates (FNA); coarse natural aggregates (CNA); Portland cement (type CEM I 42.5 R); fine recycled aggregates (FRA); coarse recycled aggregates (CRA); and industrial by-products (FA type F from a Portuguese coal power plant). The materials' characteristics are presented in Tables 1 and 2. FRA and CRA were initially recycled from a source concrete provided by Unibetao Company (Secil, Lisboa, Portugal) with 63% CEM II/A-L Class 42.5 R and 37% type II additions, equivalent to CEM IV/B. Prior to crushing, the source concrete was cured and kept outside (exposed to air) for 28 days. Regarding the construction materials to be studied, three concrete mixes (NAC, C40 FA60 NA100 and C40 FA60 RA100) were produced, with the incorporation of the mentioned raw materials (Table 3 and Figure 1). NAC was produced with 100% NA and 100% Portland cement, C40 FA60 NA100 with 40% cement, 60% FA and 100% NA, and C40 FA60 RA100 with 40% cement, 60% FA and 100% RA in weight. Figure 1: Flowchart of the methodology to perform chemical and ecotoxicological characterizations. The produced concrete specimens were cured for 28 days in a dry chamber with relative humidity of \(50\pm 5\%\) and \(22\pm 2\)\({}^{\circ}\)C air temperature. Then, the concrete specimens were fragmented through a jaw crusher in conjunction with a vertical shaft impact crusher. After that, the aggregates were sieved with 10 mm mesh aperture [30]. The three types of aggregates produced from crushing NAC, C40 FA60 NA100, and C40 FA60 RA100 were named A1, A2, and A3, respectively. The aggregates recycled from source concrete (named RA) and NAC (named A1) were almost identical, since they were both made with similar NA and cement content. The only differences were in the cement type and curing process of concrete mixes. \begin{table}
\begin{tabular}{c c c} \hline \hline
**Property** & **Cement (CEM 42.5 R)** & **FA (Type F)** \\ \hline \(\mathrm{f_{\mathrm{cm}}}\) at 28 days (MPa) & 10.1 & - \\ \(\mathrm{f_{\mathrm{cm}}}\) at 28 days (MPa) & 57.7 & - \\ Specific gravity (g/cm\({}^{3}\)) & 3.1 & - \\ Residue on 45 \(\mathrm{\SIUnitSymbolMicro m}\) sieve (\%) & 6.2 & 14.42 \\ Residue on 32 \(\mathrm{\SIUnitSymbolMicro m}\) sieve (\%) & & 22.48 \\ Final setting (min) & 231.7 & \\ Initial setting (min) & 161.1 & \\ Chemical composition (\%) & \(\mathrm{Al_{2}O_{3}}\) & 5.0 & 20.9 \\ CaO & 63.5 & 3.6 \\ CaO (L) & 1.3 & \\ Cl\({}^{\prime}\) & 0.0 & \\ Fe\({}_{2}\)O\({}_{3}\) & 3.3 & 7.4 \\ K\({}_{2}\)O & 0.6 & 1.7 \\ MgO & 1.3 & 1.0 \\ Na\({}_{2}\)O & 0.2 & 1.0 \\ SiO\({}_{2}\) & 19.5 & 57.8 \\ SO\({}_{3}\) & 3.3 & 0.6 \\ LOI & 2.4 & \\ IR & 1.2 & 3.8 \\ \hline \hline \end{tabular} Legend: \(f_{\mathrm{cm}}\) = Flexural strength; \(\mathrm{f_{\mathrm{cm}}}\) = Compressive strength; LOI = Loss on ignition; IR = Insoluble residue; FA = Fly ash.  
\end{table} 
Table 1: Characterization of cement and FA. \begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline
**Property** & \multicolumn{3}{c}{**FNA**} & \multicolumn{3}{c}{**CNA**} & \multirow{3}{*}{**FRA**} & \multirow{3}{*}{**CRA**} \\ \cline{2-2} \cline{6-7}  & **Coarse** & **Fine** & & & & **Fine** & **\({}^{\prime\prime}\)Rice** \\  & **Sand** & **Sand** & **Gravel** & & & **Grain\({}^{\prime\prime}\)** & \\ \hline Bulk density (kg/m\({}^{3}\)) [27] & 1684 & 1626 & 1385 & 1391 & 1449 & 1385 & 1280 \\ Over dried density (kg/m\({}^{3}\)) [27] & 2600 & 2594 & 2625 & 2742 & 2681 & 2218 & 2389 \\ Water absorption (\%) [27] & 0.5 & 0.4 & 1.4 & 1.2 & 1.0 & 8 & 5 \\ LA abrasion mass loss (\%) [28] & - & - & 28.6 & 27.2 & - & - & 43 \\ Shape index [29] & - & - & 15.6 & 18.0 & 17.1 & - & 25.6 \\ \hline \hline \end{tabular} Legend: LA = Los Angeles; FNA = Fine natural aggregates; CNA = Coarse natural aggregates; FRA = Fine recycled aggregates; CRA = Coarse recycled aggregates.  
\end{table} 
Table 2: Characterization of natural and recycled aggregates.