# Characterizing the Tensile Behaviour of Woven and Composite Fabrics under UV Exposure
## 4 Results and Discussions
### Tensile Properties Degradation

Table 2: Tensile properties of woven and composite geotextiles at various months of UV exposure. Figure 4: Statistical correlation matrix between the collected meteorological data from 21 November to 22 March 2022.  
well controlled in both directions, despite the anisotropic properties of geotextiles that indicated up to 8.66%. The tensile strength of the composite fabric was of particular importance, with an anisotropy of up to 15.58%. No strength losses were observed in the CD, while minimal strength losses in the MD began after the fourth month and were associated with a retained strength percentage of 94.19% following the last months of outdoor UV exposure. Overall, degradation was more pronounced in woven geotextiles, which had a lower retained strength percentage after five months of weathering testing than in composite geotextiles. The corresponding retained strain percentage in Figure 5b reveals a higher degree of non-uniformity compared to the plot of maximum strength retained percentage. Woven fabrics started to show significant strain reduction only after the second month of outdoor exposure. Inconsistency of retained strain percentages began to emerge in the third month, when woven geotextiles showed a higher (lower) retained strain percentage in the MD (CD) than the preceding month. The strain reduction for the remaining months remained steady in both MD and CD, with 91.08% and 80.74% of the strain being retained in the final months, respectively. The anisotropy of the strain retained was determined to be up to 37.77%. For the composite fabric, no strain losses were observed in the MD after five months of outdoor exposure. However, initial strain reduction occurred in CD after the first month and disappeared for the following months until the final month of outdoor UV exposure, which depicted a retained strain percentage of 82.63%. Accordingly, the emerging difference contributed to an anisotropy of up to 45.46%. Overall, the composite fabric showed a greater retained strain percentage after the final month of outdoor exposure compared to the woven fabric. The tensile strength and strain loss that engineered fabrics underwent gave a better indication of the photo-oxidation degradation that takes place during the outdoor weathering test. A comparison between both engineered fabrics indicated that woven geotextiles were subjected to a higher degradation rate than composite fabrics, which were associated with the least tensile strength and retained strain percentages after the five months of outdoor exposure. This suggested that the non-woven geotextile layer in the composite fabrics provided excellent protection for the primary load-bearing woven geotextile from photo-oxidation degradation. Moreover, the aforementioned findings show that, after several months of outdoor weathering tests, composite geotextiles exhibited higher strength and strain than virgin samples, contradicting the hypothesis made earlier. This phenomenon can be attributed to the deposition of particulate matter and pollutants in the polymer matrix, which is evidenced by the plot of retained strength percentage for composites that indicated a similar trend to the air quality index (see purple colour series in Figure 3). Notably, the deposition of dust and small dirt particles was further subjected to change by the rainfall that flushed them out. The geotextile samples were collected immediately after the rain event for 1 month (medium intensity), 2 months (medium intensity), and 4 months (high intensity). The deposition of particulate matter and pollutants was identified and attributed to an increase in tensile properties. A similar phenomenon was found by recent studies, which was mostly attributed to the sample mass per unit area increasing after the deposition of dust and microscopic dirt particles in the non-woven polymer matrix [1,7,9]. Moreover, [PERSON] et al.