Mechanical properties and durability of hydrophobically modified basalt fiber reinforced polymer bars
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摘要: 玄武岩纤维增强树脂复合材料(Basalt fiber reinforced polymer,BFRP)筋因其绿色环保、耐腐蚀性强等特点,广泛应用于海洋工程。但在长期服役过程中BFRP筋会出现吸水和被碱腐蚀导致的溶胀裂解等现象,树脂基体发生膨胀破坏,导致玄武岩纤维和基体脱粘。基体膨胀后海水中侵蚀离子加速入侵,进一步加剧BFRP筋性能退化。为了阻碍水分入侵,延长BFRP筋在海洋工程中的服役年限,通过制备氟化纳米 SiO2 改性自固化环氧树脂疏水涂层,并将其喷涂于筋表面对BFRP筋进行改性。疏水涂层使BFRP筋表面接触角从63°提高到106°。之后将BFRP筋放入25℃、45℃、60℃水和海水中进行耐久性实验,探究改性前后BFRP筋吸水率、拉伸性能在长期浸泡龄期下的变化规律。试验结果表明,疏水改性后的BFRP筋吸水率降低,其中45℃水环境中浸泡60天后,疏水改性BFRP筋吸水率比未改性筋降低40%。采用阿伦尼乌斯模型对改性前后BFRP筋的拉伸强度进行长期性能预测,疏水改性BFRP筋在长期服役过程中有更高拉伸强度保留率。通过制备氟化纳米 SiO2 改性自固化环氧树脂的疏水改性方法能够降低BFRP筋吸水率,提高强度保留率,延长服役寿命。Abstract: Basalt fiber reinforced polymer (BFRP) bars are widely used in marine engineering due to their green nature and corrosion resistance characteristics. However, BFRP bars may swell and crack because of water absorption and alkali corrosion during service, resulting in expansion and damage of resin matrix, and even the debonding between basalt fiber and matrix. Swelled matrix accelerated the invasion of water and corrosive ions, exacerbating the degradation of epoxy matrix. In order to prevent moisture intrusion and extend service life of BFRP bars in marine engineering, a hydrophobic fluorinated nano SiO2 modified epoxy resin was prepared and coated to BFRP bars. The hydrophobic resin can increase the surface contact angle of BFRP from 63° to 106°. Then the original and modified BFRP bars were immersed into in tap water and seawater at 25℃, 45℃ and 60℃ for durability test to explore their variations of water absorption and tensile properties. The experimental results show that hydrophobic modification of BFRP bars can reduce the water absorption, where the water absorption rate of hydrophobic modified BFRP bars is 40% lower than that of original bars after immersing in water at 45℃ for 60 days. The Arrhenius model has been adopted to predict the long-term performance of BFRP bars. Hydrophobic modified BFRP bars show higher tensile strength retention and longer service life than those of original BFRP. Based on above results, it is found that the hydrophobic fluorinated nano SiO2 modified epoxy resin can reduce the water absorption, improve the strength retention, and prolong the service life of BFRP bars.
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表 1 人工海水配比
Table 1. Proportion of artificial seawater
H2O/L NaCl/
(g∙L−1)MgCl2/
(g∙L−1)Na2SO4/
(g∙L−1)CaCl2/
(g∙L−1)KCl/
(g∙L−1)1.00 24.53 5.20 4.09 1.16 0.70 表 2 BFRP筋时间转换因子αTSF
Table 2. Values of time-shift factor αTSF for BFRP bars
Temperature/℃ αTSF Unmodified BFRP Modified BFRP 25 1.00 1.00 45 3.81 3.83 60 9.36 9.45 -
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