PSI - Issue 73

Miroslav Vacek et al. / Procedia Structural Integrity 73 (2025) 146–154 Miroslav Vacek, V´ıt Krˇivy´, Barbora Krˇistkova´ / Structural Integrity Procedia 00 (2025) 000–000 7 Table 4: Ratio of average monthly deposition of chloride ions measured by the wet candle method - winter season - statistical functions

152

R d , c , 1

R d , c , 2

R d , c , 3

R d , c , 4

R d , c , 5

R d , c , 6

Min (-) Max (-) Mean (-)

0.92 2.80 1.83 1.91 1.27 2.15 0.64

1.10 3.50 1.83 1.43 1.32 2.00 0.81

0.70 3.81 2.02 1.88 1.27 2.64 0.96

0.82 8.39 2.65 1.38 1.07 2.92 2.50

0.61 6.68 3.18 2.89 2.32 3.63 1.85

1.05

24.34 10.07

Median (-)

7.44 5.21

1st quartile (-) 3rd quartile (-)

12.30

σ ( − )

8.66

4. Discussion

As shown in Tables 2, 3 and 4 and also in Figures 5 and 6, noise barriers have a significant role in reducing chloride deposition. However, changes in barrier height alone do not lead to substantial di ff erences in deposition, especially when such changes are relatively small. The most influential factor that a ff ects chloride deposition is the distance of the barrier from the road. Chloride ion deposition tends to be higher during the winter season. For example, at the closest monitoring stand (stand 6, obverse surface), the deposition reached 375.03 mg / (m 2 · day) in January 2024. This elevated value may be due to proximity to the road, where splashing can directly impact the wet candle, causing it to register not only airborne deposition but also direct contamination. At the most distant stand, but also on the obverse surface, the maximum value observed was significantly lower, 24.62 mg / (m 2 · day) in December 2023. It is evident that both the distance from the road and the height of the noise barrier significantly influence the level of chloride ion deposition. These parameters also a ff ect the chloride deposition measured on the obverse and reverse surfaces of the barrier. The highest deposition ratios ( R d , c , i ) are found in the closest monitoring stand, and these values exhibit considerable variance. Higher ratios are particularly prominent during winter, as demonstrated in Figures 5 and 6 and supported by Tables 3 and 4. These findings indicate that noise barriers and similar physical obstacles can substantially reduce the level of chloride ion deposition, especially when they are close to the source. Figure 5 illustrates a clear and increasing trend in the deposition ratio ( R d , c , i ) as the distance from the road decreases. Furthermore, the variability of this ratio tends to decrease with increasing distance, suggesting a stabilizing e ff ect of distance on chloride deposition patterns. This study highlights the significant influence of terrain layout and structural placement on chloride ion deposition. In this article, attention has been paid to the e ff ect of the noise barrier. The noise barrier e ff ectively reduces the deposition of chloride ions. Especially in winter season and on the obverse and reverse surfaces large di ff erences can be observed. These di ff erences are presented in the study as a ratio. Chloride ion deposition was found to be markedly higher on the obverse surfaces (road-facing) compared to the reverse surfaces. For example, at stand 6 (2 meters from the road), the obverse surface recorded a peak deposition of 375.03mg / (m²·day) in January 2024, while the reverse surface was below the detection limit or significantly lower. In contrast, the most distant obverse surface (stand 1, 17 meters from the road) recorded a maximum of only 24.62 mg / (m²·day). The ratio of chloride deposition between the obverse and reverse surfaces (Rd,c,i) further quantifies the shielding e ff ect of the noise barrier. The mean ratio on stand 6 was 7.05, with a mean in the winter season of 10.07, indicating that the reverse surface received approximately 85 to 90 % less chloride deposition than the side facing the road. Even at greater distances, such as stand 1, the mean ratio remained 1.51 (or 1.83 for the mean of the winter season), confirming the consistent e ff ectiveness of physical shielding. 5. Conclusion