# Field Trial and Performance Evaluation of Soybean-Based Bio-Fog Seals for Asphalt Rejuvenation
## 3 Results
### Pavement Friction  
Our analysis of the sand patch test results (Figure 8) using a one-way ANOVA with [PERSON]'s post-hoc test (\(\alpha\) = 0.05) revealed no statistically significant difference in MTD between pre- and post-treatment. Additionally, the test did not detect a significant difference between measurements taken in the middle of the lane (MDL) and the outer wheel path (OWP) within each section. However, it is important to note that the test can be sensitive to location-specific factors, as evidenced by the differences observed in the \"before\" treatment measurements across sections in the same test section. In Figure 9, the BPN results demonstrate that all MnROAD test sections, regardless of treatment, and location (MDL, OWP), exceeded the minimum requirement of 55 for heavily trafficked urban roads. Statistical analysis using a \(t\)-test and [PERSON]'s HSD test confirmed no significant difference (\(p\) > 0.05) in BPN between control and treated sections. This suggests successful penetration of the bio-fog seal into the pavement matrix, avoiding completely coating the aggregates that could negatively affect microtexture and friction. Figure 8: Macrotexture evaluation of the treated and untreated sections with Sand Patch test. Figure 7: Pavement before and after the bio-rejuvenator application: (**a**) surface appearance and (**b**) texture. As expected, skid resistance was higher in dry compared to wet conditions. Interestingly, BioMag-treated sections displayed an increase in wet skid resistance compared to control sections. This phenomenon might be attributed to the biopolymer component within BioMag, which could enhance surface tackiness in wet conditions, thereby increasing friction. In contrast to the BPN findings, DFT measurements conducted one month after application (Figure 10) revealed a significant difference at 95% confidence level in skid resistance between treated and untreated sections in the two MnROADs. Specifically, the DFT results showed lower friction coefficients for both BioMag- and SESO-treated sections compared to the control sections, despite all sections exceeding the minimum required friction coefficient of 0.35 (red line) for safe driving conditions. This reduction in friction highlights the need to consider both the age and existing friction characteristics of the pavement in the decision-making process for application of bio-fog seal treatments. Agreeing with the sand patch and BPN results, the location within the lane, MDL or OWP, did not appear to affect the results, as the measurements showed a consistent pattern across both placements. Figure 10: Friction coefficient from DFT at 40 mph (65 km/h). Figure 9: BPN of MnROAD test sections. However, the St. Michael section did not exhibit a substantial difference in friction coefficient between treated and untreated sections. A possible explanation for this could be attributed to the higher traffic volume in this section, which might accelerate the wear-off process of the seal from the pavement surface and, in so doing, reducing the differential impact observed in friction. In the St. Michael test section, the changes in friction were monitored over time, as demonstrated in Figure 11. The data indicate that, while the friction of treated sections was statistically significantly lower (\(p<0.05\)) compared to the control section (pink region) throughout the monitoring period, all sections maintained friction coefficients exceeding the minimum threshold of 0.35 (red line). This indicates that opening the road to traffic 30 min after application would be safe, causing minimal disturbance, and there is no need for a blotter material to increase friction. A more evident reduction in the treated sections was observed around 90 min after application. This decrease in friction for the treated sections compared to the control might be due to the breakdown of the emulsion in the bio-fog seal, resulting in the evaporation of water and leaving behind oil residues.