## 3 Results and Discussion
### Recommended SPRG Viscosity Modifier Content for Respective Surface Humidity Ratio Ranges  
Based on the adhesive strength results and the subsequent coefficient of determination, it was confirmed that the adhesive strength of the SPRG on a wet surface can be affected by the viscosity of the waterproofing agent, and that the adhesion strength increases as the viscosity increases. On the basis of the high coefficient of determination and the reliability of the relation between viscosity and wet surface adhesion performance limited to the SPRG materials, the adhesion strength difference each specimen type between the 0% humidity ratio condition (completely dry) and 100% humidity ratio condition (completely wet) were derived. Given the scope of this study, the results would indicate that the greater difference of the range signifies high variance of performance (indicating a low level of consistency). Although D6 and D8 display a significantly high level of viscosity, meaning the difficulty of workability at site, it is not impossible to work with. In contrast, D1-D3 have the lowest viscosity, indicating low manufacturing costs as well as labor due to higher workability, at the risk of loss of adhesion performance. It is expected at all times that waterproofing installation proceed in accordance to manufacturer specifications, whereby construction conditions should maintain an as dry as possible condition on the concrete or substrate surface, but as this is not always the case, builders should always be aware of limitations of the adhesive performance of SPRGs on various wet surface conditions. As the question remains to be whether the trade-off on the workability and performance is worth the benefits, Figure 7 was derived to provide an illustration on the adhesion strength difference derivation results as a means to recommend an optimal viscosity modifier content for the SPRGs for various surface humidity ratio conditions. \begin{table}
\begin{tabular}{c c c} \hline
**Specimen Type** & **Linear Regression Equation** & **Coefficient of Determination (\(R^{2}\))** \\ \hline D1 & y = \(-5.6\times 10^{-3}\)x + 0.0126 & 0.9362 \\ D2 & y = \(-5.9\times 10^{-3}\)x + 0.0148 & 0.9531 \\ D3 & y = \(-7.9\times 10^{-3}\)x + 0.0178 & 0.9631 \\ D4 & y = \(-8.6\times 10^{-3}\)x + 0.0190 & 0.9895 \\ D5 & y = \(-8.7\times 10^{-3}\)x + 0.0196 & 0.9732 \\ D6 & y = \(-9.5\times 10^{-3}\)x + 0.0203 & 0.8964 \\ D7 & y = \(-1.1\times 10^{-2}\)x + 0.0230 & 0.9705 \\ D8 & y = \(-1.1\times 10^{-2}\)x + 0.0246 & 0.9746 \\ \hline \end{tabular} Note: y: Adhesive Strength (N/mm\({}^{2}\)). x: Substrate Surface Humidity (%).  
\end{table} 
Table 6: Coefficient of Determination of Linear Regression Relation of Viscosity (Specimen Type) based on the Increase of Substrate Surface Relative Humidity Ratio (%). In the case of the SPRG, if the upper limit viscosity range for workability during construction exceeds 5,000,000 mPa's, poor workability at the construction site has been documented to be an issue [14]. In this regard, despite the high viscosity variants of the specimens (D6-D8, marked as red in Figure 7) having notably higher ranges of adhesive strength, it is not recommended for an SPRG with this range of viscosity to be used. Furthermore, the adhesion strength differences at the 0% humidity ratio condition and 100% humidity ratio condition were also higher as the viscosity increased, indicating that the reduction in adhesive strength is also greater as the viscosity increases. On the other hand, specimens that had low viscosity, while having had low overall adhesive strength, also had more consistent adhesive strength performance (indicated by the lower adhesion strength differences at the 0% humidity ratio condition and 100% humidity ratio condition). Furthermore, lower viscosity naturally indicates easier workability, thus this study can recommend (based on the limitations of this study scope) SPRG of D3 type level of viscosity that has moderately high adhesive strength performance and low adhesive strength difference.