## 2 Experimental Program
### Mix Proportions  
The process of finding the proportions of GPC mix is different than the OPC concrete mix. In the OPC concrete mix design, the quantity of water and cement are calculated first, after which the quantity of aggregates (CA and sand) is worked out. However, the mix design process of GPC involves more parameters, i.e., source materials, AAS content, SS/SH ratio, curing temperature, molarity of SH, etc. Therefore, it is relatively challenging to proportion such a mix appropriately against a specified target strength. In the present study, twenty trial design mixes have been considered with the aim to study the influence of various parameters on the fresh and hardened properties of FS-GPC cured at ambient temperature. The literature on mix design of GPC, in which quantities and ratios of the constituents can be calculated to get the specific properties, i.e., slump or strength, etc., is scarce. Therefore, each mix in the present study was prepared by allotting the specific percentages by mass to all the individual constituents. The optimal ranges of all the constituents are \begin{table}
\begin{tabular}{c c c} \hline
**Oxides** & **FA (\%)** & **SG (\%)** \\ \hline SiO\({}_{2}\) & 54.55 & 34.2 \\ Al\({}_{2}\)O\({}_{3}\) & 31.93 & 14.2 \\ Fe\({}_{2}\)O\({}_{3}\) & 3.12 & 0.76 \\ Na\({}_{2}\)O & 0.25 & 0.3 \\ CaO & 4.65 & 44.95 \\ SO\({}_{3}\) & 0.4 & 1.75 \\ K\({}_{2}\)O & 0.7 & 0.5 \\ P\({}_{2}\)O\({}_{5}\) & 0.45 & 0.05 \\ MgO & 1.42 & 0.95 \\ TiO\({}_{2}\) & 1.15 & 0.5 \\ LOI & 0.95 & 1.6 \\ Specific Surface Area (m\({}^{2}\)/kg) & 320.7 & 405 \\ Specific Gravity & 2.1 & 2.8 \\ \hline \end{tabular}
\end{table} 
Table 1: The chemical composition and physical properties of FA and SG. \begin{table}
\begin{tabular}{c c} \hline
**Entity** & **Seedication** \\ \hline Color & Colorless \\ Density, kg/m\({}^{3}\) & 1460 \\ Total solid content & 48 (\% mass) \\ \hline \end{tabular}
\end{table} 
Table 2: The properties of SS solution. \begin{table}
\begin{tabular}{c c c} \hline
**Entity** & **Sand** & **CA** \\ \hline Relative Density & 2.64 & 2.70 \\ Bulk Density (kg/m\({}^{3}\)) & 1688.4 & 1644.5 \\ Fineness Modulus (kg/m\({}^{3}\)) & 2.50 & 7.65 \\ Water Absorption (\% mass) & 1.40 & 1.20 \\ \hline \end{tabular}
\end{table} 
Table 3: The physical properties of CA and sand. selected from the previous studies available in the literature [25; 26; 28; 29; 30; 31; 32; 33]. A number of FA and SG based GPC mixes with different slag content, AAS content, SH concentration, SS/SH ratio, and water content were prepared and tested. The mixes were divided into five groups, A, B, C, D, and E, as shown in Table 4. The mixes were devised by varying one parameter while the others were kept constant to investigate the influence of a certain mix design parameter on the engineering properties of geopolymer matrix. In group A, the mixes were prepared with different FA/SG ratios, i.e., 90/10, 80/20, 70/30, and 50/50; with a varying slag content, i.e., 10%, 20%, 30%, and 50% respectively; while all the other parameters were kept constant, i.e., molarity of SH solution (M = 10), SS/SH = 2.0, and AAS content as 40%. In group B, the mixes were prepared with two different molarities of the SH solution (i.e., 12 M and 14 M) and were compared with 10 M mixes of group A, to study the influence of SH concentration. The AAS content was varied from 40% (group A and B mixes) to 35% in group C mixes to study the influence of AAS content, keeping all the other parameters same as group A. In group D, the mixes were prepared using two different SS/SH ratios (2.5 and 3.0) and compared to the respective mixes of group A (SS/SH = 2.0) to investigate the effect of different SS/SH ratios. Lastly, in group E, the mixes were prepared with extra water (12 kg/m\({}^{3}\)), keeping all the other parameters same as group C to investigate the consequence of addition of extra water on the properties of geopolymer matrix. All the mixes were named based on the group and amount of slag content.