湿热环境对BFRP筋拉伸性能的影响

Tensile Property of BFRP Under Hygrothermal Environment

在海洋工程中,海水中Cl^-、SO_4^(2-)和Mg^(2+)会侵蚀进入钢筋混凝土内部,造成混凝土的膨胀破坏,严重影响混凝土结构的耐久性。BFRP筋具有优良的耐腐蚀性能,可以避免钢筋锈蚀带来的耐久性问题,因而在海工混凝土领域具有广阔的应用前景。该文研究了湿热环境下BFRP筋的吸水性能,并探讨了BFRP筋在蒸馏水、碱溶液和海水中浸泡不同龄期的拉伸性能变化规律。试验结果表明:湿热环境下,BFRP筋在蒸馏水和碱溶液中的吸水过程分为两个阶段,浸泡早期BFRP筋的吸水速率快速增加,后期吸水速率减慢。在蒸馏水、碱溶液和海水中浸泡,BFRP筋的拉伸性能随浸泡温度和浸泡龄期的增长而逐步下降,且随着温度的提高,下降幅度较大。在海水浪溅区暴露半年之后,BFRP筋的拉伸性能基本保持不变。

In marine engineering, the reinforced concrete will generate expansion damage attacked by chloride ions, sulfate ions,and magnesium ions, which seriously affecting the durability of concrete structure. Basalt fiber reinforced polymer （BFRP） rebarhave excellent corrosion resistance, which can avoid the durability problems caused by corrosion. Therefore, BFRP rebar have awide application prospect in marine concrete field. In this study, the effects of hygrothermal environment on the moisture absorptionbehavior of BFRP bars have been investigated. In addition, the degradation regularity of tensile properties of BFRP bars underdistilled water, alkali and seawater environment have been characterized. The results show that the water absorption of BFRP tendsto be a two - phase water absorption behavior under the water or alkali solution. The water absorption rate increases rapidly in theearly stage and slows down in the later stage. The tensile properties of BFRP bars declines gradually with the increase of the soakingtemperature and the soaking time, and the descent degree increases with the increase of the soaking temperature under distilledwater, alkali and seawater environment. After half a year of exposure at the seawater splashing zone, the tensile property of theBFRP bars basically remains unchanged.