## 3 Experimental Regime
### Experimental Plan  
#### 3.2.1 Base Load Derivation  
In general, the amount of pressing (installation) load required for tiles is difficult to exactly quantify in construction sites. In this regard, the ISO standard test method (ISO  
\begin{table}
\begin{tabular}{c c c} \hline
**Item** & **Spot-Bonding Method** & **Trowed Adhesion Method** \\ \hline Adhesion Strength & 0.4–0.6 N/mm\({}^{2}\) & 1.5–4.0 N/mm\({}^{2}\) \\  & & \\ Concept Illustration & & \\  & & \\  & & \\  & & \\  & & \\  & & \\  & & \\  & & \\  & & \\ \end{tabular}
\end{table}
Table 2: _Cont._  
\begin{table}
\begin{tabular}{c c c} \hline
**Criteria** & **Detailed Content** & **Standard** \\ \hline \multirow{4}{*}{Materials} & Adhesive for spot-bonding & General cementitious adhesive (ready-made) OPC & ISO 13007-1 \\  & & 20\%, sand 80\%, additive 0.5\% & \\  & & Ceramic tile (250 \(\times\) 400 mm) & \\  & & Absorptivity 13.2\% & ISO 10545-2 \\  & Tile & Firing temperature: 1000–1200 \({}^{\circ}\)C & ISO 13007-2 \\  & & Flexural strength 103.7 N/cm & \\  & Concrete substrate & Concrete 400 \(\times\) 400 mm & ISO 13007-2 \\  & Specim tile size & 250 \(\times\) 400 mm & N/A \\  & & Plate (metallic disc) square (50 \(\pm\) 1) mm side & \\  & Adhesion strength & Test speed (250 \(\pm\) 50) N/s & ISO 13007-2 \\  & & Glue epoxide & \\  & Spot-bonding interface surface area & 100\%, 80 \(\pm\) 2%, 60 \(\pm\) 2\% & N/A \\  & & Cured for 28 days under standard ambient conditions & \\  & & (temperature 23 \(\pm\) 2 \({}^{\circ}\)C, humidity 50 \(\pm\) 5\%) & ISO 13007-2 \\ \hline \end{tabular}
\end{table}
Table 3: Experimental scope summary.  
13007-2) suggests applying a load of 20 \(\pm\) 0.05 N for 30 s on top of a 50 \(\times\) 50 mm tile specimen [18]. However, this is applicable to the troweled adhesion method, where an evenly distributed adhesive across a specimen surface is present. For the spot-bonding method, tile installation is mainly dependent on the worker's workmanship: the variable is much greater [20]; thus, the standard load application by pressing force to install the tile, the load and time exerted by the worker when constructing a tile in the actual site are calculated, and the average working load is calculated through this, and this force is standardized. It was intended to prepare the attached specimen using a pressing load.  
In order to derive an applicable evaluation methodology for assessing the ratio of the stable adhesion area for spot-bonded tiles, first, an applicable load was derived based on the estimated amount of force applied by the average worker. To this end, a separate experiment was conducted where each of the upper, middle, and lower sections based on the height of the bathroom wall of the house (2300 mm) was installed with tiles by four adult males in their 20 s and 40 s. For the tile application, a single 250 \(\times\) 400 mm tile was applied to a wall structure. The force and time of pressing while attaching the tile were measured and presented as the basis for the weight when making the specimen. Refer to Table 4 for details.  
As a result of the specimen preparation procedure, the average of the four was found to be 64.5 N (5.5 s) in the upper part, 116.8 N (8.5 s) in the middle part, and 83.3 N (6.8 s) in the lower part, and the overall average was 88.2 N (6.9 s). Based on the average of the average results, it was decided to apply a pressure load of up to 7 s using a 100 N weight on the top of the tile when manufacturing the specimen. It must be kept in mind that for the replicability of evaluation in the future, results might vary as the above testing would need to be reconducted in accordance with different national standards or circumstances.