Accelerated aging assessment of physicochemical changes in non-metallic pipe materials due to chlorine exposure
비금속 재질인 PB, PE, PVC 수도관을 대상으로 염소 노출에 의한 물리⋅화학적 구조변화를 관찰하여 내구성에 미치는 영향을 평가하고자 하였다. 염소 노출은 NaOCl을 적용하여 0.4에서 2.1 g⋅hr/L의 노출 강도가 높아짐에 따라 PE, PB의 표면 형상 변화는 결정화와 crack이 일어남을 확인할 수 있었다. 또한 구성성분 비율과 작용기 변화는 aldehyde, ketone에 의한 carbonyl group 생성을 확인하였고 모든 재질에서 산화 과정이 연속적으로 일어나는 결과를 나타내었다. 이에 따른 내구성 변화는 인장강도와 신도를 측정하여 평가한 결과이며 최소 5에서 20 %의 초기상태 대비 변형률을 나타내었다. 최종적으로 염소 노출에 의한 취약성은 PB > PE > PVC 순서와 같으며 향후 갱생과 교체 주기 산정을 위한 진단 방법론으로 활용 용도가 높을 것으로 판단된다.
This study aimed to evaluate the effects of chlorine exposure on the durability of non-metallic water pipes made of polybutylene (PB), polyethylene (PE), and polyvinyl chloride (PVC) by investigating their physicochemical and structural changes. Chlorine exposure was induced using sodium hypochlorite (NaOCl), with exposure intensities ranging from 0.4 to 2.1 g⋅hr/L. As the exposure intensity increased, surface morphological changes, including crystallization and crack formation, were observed in PE and PB. In addition, analyses of compositional ratios and functional groups revealed the formation of carbonyl groups, such as aldehydes and ketones, indicating that oxidative reactions continuously occurred in all materials. The resulting changes in mechanical durability were evaluated by measuring tensile strength and elongation at break, which exhibited reductions of 5–20% compared with the initial condition. Finally, the susceptibility to chlorine-induced degradation was found to follow the order PB > PE > PVC. These findings suggest that the proposed approach can serve as an effective diagnostic methodology for determining the rehabilitation and replacement cycles of non-metallic water pipes.