## 5 Results and Discussion
### Comparison of Mass and Density Properties  
Recording the change in mass of specimens under the two exposure conditions was carried out in this study along with reporting the density changes. After 28 days of curing, the cylindrical specimens recorded an average weight of 3.53 kg and a density of 2251 kg/m\({}^{3}\). The test specimens immersed in the marine tanks were taken and surface dried before recording the weight at each interval. The test specimens' weight changes were recorded monthly and are depicted in Table 4 and Figure 5 below.  
It is observed that after three months of exposure in ambient conditions, the weight changes remained in the range of 3.50 to 3.52, reporting a weight loss of up to 1%, which confirms the observations from other studies reported in the literature [43, 44, 45]. This is also less than that of conventional OPC concrete/self-compacting concrete under similar conditions, where the weight loss was reported in the range of 1.1% to 2% [43].  
For the marine exposure, the sample weight increased in the range of 1.1% to 1.9% over three months of exposure compared to the 28-day weight of specimens. Under marine conditions, a significant amount of water is trapped inside the samples because the natural evaporation is prevented by the alternating wet-dry cycles and higher moisture in the environment [4]. This additional water aids in the hydration of any unreacted species in the geopolymer concrete, creating a more robust geopolymer matrix, which can be reflected by the slight increase in the weight of the specimens [4]. Specifically, in a calcium-rich geopolymer concrete, such as like SCGC, this additional hydration reaction will lead to the formation of C-A-S-H gels, which reduce the porosity and condense the microstructure of the alkali-activated geopolymer matrix, leading to weight changes as reported in similar studies [4, 46, 47]. The weight change was reflected in the density changes, as shown in Table 5 and Figure 6 below.  
\begin{table}
\begin{tabular}{c c c c c c c} \hline \hline  & \multicolumn{3}{c}{Weight of Specimens, kg} & \multicolumn{2}{c}{Percentage change in} & \multicolumn{2}{c}{Percentage change in} & \multicolumn{2}{c}{Percentage change in} \\  & \multicolumn{3}{c}{} & \multicolumn{3}{c}{weight between} & \multicolumn{2}{c}{weight between} & \multicolumn{2}{c}{weight between} \\ Days of Exposure & Value of 28-daycured & Ambient & Marine & 28-day value and ambient conditioned & 28-day value and ambient and marine \\  & \multicolumn{3}{c}{} & \multicolumn{3}{c}{} & \multicolumn{3}{c}{samples (\%)} & \multicolumn{2}{c}{samples (\%)} & \multicolumn{2}{c}{samples (\%)} \\ \hline
30 & & 3.52 & 3.57 & 0.28 (\(-\)) & 1.13 (\(+\)) & 1.42 (\(+\)) \\ \hline
60 & 3.53 & 3.51 & 3.60 & 0.57 (\(-\)) & 1.98 (\(+\)) & 2.56 (\(+\)) \\ \hline
120 & & 3.50 & 3.61 & 0.85 (\(-\)) & 2.26 (\(+\)) & 3.14 (\(+\)) \\ \hline \hline \end{tabular} Note: (\(+\)) corresponds to an increase in value, (\(-\)) corresponds to a decrease in value.  
\end{table}
Table 4: Comparison of weight changes under ambient and marine exposure conditions.  
Figure 5: Weight of ambient and marine exposed specimens.  
As in the case of the weight change patterns, the ambient conditioned specimens followed a decreasing trend in density, reporting a loss in the density of up to 1% compared to conventional OPC-based concretes during a three-month exposure. Again, the marine exposed specimens reported an increase in density proportionate to weight changes, which seemed to stabilise over three months. However, the lack of a drop in the weight after the three-month exposure to harsh marine conditions ensured that no leaching or salt attack occurred on the cylindrical specimens after three months of exposure to wet-dry conditions.