## 4 Experimental Results and Discussions
### Comfort Level of Pedestrian Walking  
A golf ball (GB) and a steel ball (SB) were dropped from a height of 100 cm (H) onto the paved surface in order to evaluate the rebound characteristics of different paving materials. The resulting rebound heights were recorded. Figure 11a shows that the GB factor increased with an increase in stabilizer content, while it decreased with an increase in wood chip content. Specifically, the maximum GB factor increased 2.34-fold from 35 to 82 when the stabilizer content increased from 5% to 15%. Additionally, the GB factor decreased by up to 31% when the wood chip content increased from 0.5% to 1.5%. In conclusion, the GB test, conducted to assess walking comfort, demonstrated that lower stabilizer content and higher wood chip content resulted in better impact absorbance. According to Figure 11b, the SB factor followed a similar trend to the GB factor. It increased with higher stabilizer content and decreased as the wood chip content increased. Specifically, the maximum SB factor showed a significant increase from 9 to 18 when the stabilizer content increased from 5% to 15%. Conversely, the SB factor experienced a substantial 64% decrease when the wood chip content increased from 0.5% to 1.5%. In conclusion, the SB test, which evaluated  
Figure 10: Effect of wood chip and stabilizer contents on permeability.  
Figure 9: Effect of various wet–dry cycles on relative dynamic elastic modulus with various stabilizer contents containing 1.5% wood chips.  
walking comfort, revealed that lower stabilizer content and higher wood chip content resulted in improved impact absorbance, leading to a better walking experience.  
It is commonly believed that the GB factor reflects impact absorbance, while the SB factor represents rebound resilience. It is widely held that smaller values of these factors correspond to a lower risk of significant bodily impact for pedestrians. The SB/GB ratio, which indicates the walking comfort level, was analyzed to compare the impact load experienced by the human body in relation to stabilizer and wood chip contents. It was found that the SB/GB ratio decreased with higher wood chip content while maintaining a constant stabilizer content, as shown in Figure 12. Notably, when conducting a comparison to 0.5% wood chip content with stabilizer content 5%, a significant decrease in the SB/GB ratio was observed at a wood chip content of 1.5%. This suggests that higher wood chip content in the soil brick leads to greater walking comfort. The analysis results indicate that the soil brick used in this study greatly improves walking comfort compared to cementitious soil paving materials by achieving lower rebound resilience (0.012-0.020) and higher impact absorbance (0.055-0.167). In conclusion, the SB/GB testing performed to assess the walking comfort level of soil bricks verifies that the soil brick used in this study has superior impact absorbance compared to cementitious bricks. It is expected to significantly reduce the impact load on the human body when used as paving material for pedestrian paths such as promenades, hiking trails, and sports facilities.