Bazli Milad, Ashrafi Hamed, Jafari Armin, Zhao Xiao-Ling, Raman R K Singh, Bai Yu
Department of Civil Engineering, Monash University, Clayton, Victoria 3800, Australia.
Structural Research Center, International Institute of Earthquake Engineering and Seismology (IIEES), Tehran 19537-14453, Iran.
Polymers (Basel). 2019 Aug 26;11(9):1401. doi: 10.3390/polym11091401.
The present study indicates the importance of using glass fiber reinforced polymer (GFRP) laminates with appropriate thickness and fibers orientation when exposed to harsh environmental conditions. The effect of different environmental conditions on tensile properties of different GFRP laminates is investigated. Laminates were exposed to three environmental conditions: (1) Freeze/thaw cycles without the presence of moisture, (2) freeze/thaw cycles with the presence of moisture and (3) UV radiation and water vapor condensation cycles. The effect of fiber configuration and laminate thickness were investigated by considering three types of fiber arrangement: (1) Continuous unidirectional, (2) continuous woven and (3) chopped strand mat and two thicknesses (2 and 5 mm). Microstructure and tensile properties of the laminates after exposure to different periods of conditioning (0, 750, 1250 and 2000 h) were studied using SEM and tensile tests. Statistical analyses were used to quantify the obtained results and propose prediction models. The results showed that the condition comprising UV radiation and moisture condition was the most aggressive, while dry freeze/thaw environment was the least. Furthermore, the laminates with chopped strand mat and continuous unidirectional fibers respectively experienced the highest and the lowest reductions properties in all environmental conditions. The maximum reductions in tensile strength for chopped strand mat laminates were about 7%, 32%, and 42% in the dry freeze/thaw, wet freeze/thaw and UV with moisture environments, respectively. The corresponding decreases in the tensile strength for unidirectional laminates were negligible, 17% and 23%, whereas those for the woven laminates were and 7%, 24%, and 34%.
本研究表明，在暴露于恶劣环境条件下时，使用具有适当厚度和纤维取向的玻璃纤维增强聚合物（GFRP）层压板非常重要。研究了不同环境条件对不同GFRP层压板拉伸性能的影响。层压板暴露于三种环境条件下：（1）在无水分的情况下进行冻融循环；（2）在有水分的情况下进行冻融循环；（3）紫外线辐射和水蒸气凝结循环。通过考虑三种纤维排列方式研究了纤维配置和层压板厚度的影响：（1）连续单向；（2）连续编织；（3）短切毡，以及两种厚度（2和5毫米）。使用扫描电子显微镜（SEM）和拉伸试验研究了层压板在暴露于不同老化时间（0、750、1250和2000小时）后的微观结构和拉伸性能。使用统计分析对所得结果进行量化并提出预测模型。结果表明，包含紫外线辐射和潮湿条件的环境最为恶劣，而干燥的冻融环境最温和。此外，在所有环境条件下，短切毡和连续单向纤维层压板的性能分别经历了最大和最小的下降。短切毡层压板在干燥冻融、潮湿冻融和紫外线与潮湿环境中的拉伸强度最大降幅分别约为7%、32%和42%。单向层压板的拉伸强度相应下降可忽略不计、17%和23%，而编织层压板的下降分别为7%、24%和34%。
