不同侵蚀环境下玄武岩纤维筋的耐腐蚀性及强度变化规律研究

Study on the corrosion resistance and its strength variation of BFRP tendon under different corrosion environments

侵蚀环境下玄武岩纤维筋(BFRP筋)的耐腐蚀性和强度变化直接关系到BFRP筋预应力锚索的锚固性能和加固效果,通过配制pH为3、8、13的酸碱溶液、人工海水、蒸馏水等5种侵蚀溶液模拟不同侵蚀环境,进行了BFRP筋的耐腐蚀性与强度变化规律研究,结果表明:侵蚀溶液作用前后BFRP筋保持线弹性变形行为,经过不同溶液浸泡后BFRP筋强度随浸泡时间呈现出近似线性的衰减趋势,随浸泡时间增加,当浸泡溶液渗入环氧树脂基体内部后,由于溶液对环氧树脂基体的固化交联作用增强,环氧树脂基体强度增加,而侵蚀溶液长期作用下溶液与玄武岩纤维硅氧四面体桥氧的化学反应造成筋材内部结构缺陷是导致BFRP筋强度降低的主要原因。相比于酸性溶液、蒸馏水、人工海水,碱性溶液与玄武岩纤维的化学反应更为剧烈,在其侵蚀作用下BFRP筋的强度降低最为明显。研究成果可为BFRP筋广泛应用于各类腐蚀环境下岩土锚固工程提供参考和技术指导。

The corrosion resistance and strength variation of basalt fiber reinforced polymer(BFRP) tendon under different corrosion environments is directly related to its anchoring performance and the reinforcement effect of geotechnical engineering for the BFRP tendon prestressed anchor cable. The corrosion resistance and strength variation of BFRP tendon was studied after being treated by the acid solution of pH=3, the alkaline solution of pH=8 and 13, the solution of artificial seawater and distilled water. It shows that whether the BFRP tendon was treated by these corrosion solutions or not, it has a linear elastic deformation behavior. However, its strength variation shows an approximate negative linear relationship to the corrosion time. With the increase of corrosion time, as the corrosion solution penetrates into the epoxy resin matrix of the BFRP tendon, the strength of the epoxy resin matrix increases due to the enhancement of the curing cross-linking effect. The primary factor that decreases the strength of the BFRP tendon is the structural defects of the basalt fiber caused by the chemical reaction between the corrosion solution and the silica-oxygen tetrahedral bridge oxygen of the basalt fiber. Compared with the acidic solution, the distilled water and the artificial seawater, the chemical reaction between the alkaline solution and the basalt fiber is more active, which makes the strength decrease of the BFRP tendon drastically.