## 4 Mechanical Properties of Geopolymer Concrete
### Efficiency of Alkaline Solution and Ambient Condition on GPC
\begin{table}
\begin{tabular}{c c c} \hline
**Author** & **Aim** & **Results** \\ \hline \multirow{6}{*}{[PERSON] et al. (2018)} & \multirow{6}{*}{The effect of fly ash on strength of high-volume fly ash mortar} & The compressive strength of fly ash mortar (50\% FA) was significantly increased, comparable to that of OPC mortar at 7 days. The incremental trend of concrete strength was considerably observed up to 91 days, and after this age the rate of increase was lower compared to 91 days and other early ages. \\ \cline{2-3}  & & In spite of the effective role of fly ash partially replaced with type V Portland cement on improvement of sulfate resistance, this result was not as much as expected as it hardly went beyond 15\% in the best performance. Overall, 15\%, 20\% and 25\% fly ash had the lowest expansion and highest strength of 333 and 416 kg/m\({}^{3}\), respectively. \\ \hline \multirow{2}{*}{[PERSON] et al. (2018)} & \multirow{2}{*}{\begin{tabular}{c} Mechanical properties and environmental impacts of pervious concrete containing fly ash based on the C/A ratio \\ \end{tabular} } & C/A has a significant influence on the properties of \\  & &  previous concrete. C/A ratio in the range of 0.20-0.24 and \\ \cline{2-3}  & &  fly ash based on the C/A ratio \\ \cline{2-3}  & &  previous concrete and porosity. \\ \hline \multirow{2}{*}{[PERSON] et al. (2018)} & \multirow{2}{*}{\
\begin{tabular}{c} The effect of optimum mix design of GPP on GPC properties \\ \end{tabular} } & The inclusion of 40\% GGBPS in GPP content was found as an optimum mix design. GPC properties based on optimum mix design of GPP were also better compared to OPC properties. \\ \hline \multirow{2}{*}{[PERSON] et al. (2018)} & \multirow{2}{*}{
\begin{tabular}{c} The comparison of SP effect on GPC and OPC \\ \end{tabular} } & SP has the key role in the reduction of permeability value. \\  & &  Durability improvement was seen for concrete specimens containing SP compared to those without SP. \\ \hline \end{tabular}
\end{table} 
Table 3: _Cont._involved by this value of chemical ratio has the highest compressive strength among all mix designs used for this research. In the case of GPC workability, the slump test indicated that GPC in the fresh state has high viscosity and is workable enough without adding extra water. This result was achieved by the GPC concrete with a high density of 2415 kg/m\({}^{3}\) after blending concrete materials. [PERSON] et al. [45] presented a wide laboratory schedule in order to obtain the achievements on the mechanical properties of GPC replacing 0%, 25%, 50%, 75%, 100% fly ash to OPC in the proposed mix design of this study. Two solutions of sodium hydroxide (NaOH) and sodium silicate (Na\({}_{2}\)SiO\({}_{2}\)) were employed in this program as an activator solution due to cement hydration. The temperature of 60\({}^{\circ}\)C for the curing time of 48 h was considered to achieve the optimum strength desired in this test. The significant scope of this study was to check the mechanical properties of GPC as the replacement of conventional concrete using different activator solution ratios and other experimental conditions. For the reason that some factors such as curing period, alkaline solution composition and diverse binder content may be effective on the properties of natural pozzolan-based alkali-activated concrete (ACC), [PERSON] et al. [46] performed a laboratory program by varying the weight ratio of sodium silicate to sodium hydroxide (SS/SH) from 2.0 to 2.75 and various binder content between 350 kg/m\({}^{3}\) and 450 kg/m\({}^{3}\). In this study, a number of concrete properties such as setting time in alkali-activated pastes, concrete workability and compressive strength were examined. In the case of compressive strength, the specimens for 0.5, 1, 3, 7, 14, and 28 days kept in an oven at 60\({}^{\circ}\)C were considered for this investigation.