Creep strain control by pretension for basalt fiber-reinforced polymer tendon in civil applications

• Published in: Materials & design 2016-01, Vol.89, p.1270-1277
• Main Authors: Wang, Xin, Shi, Jianzhe, Wu, Zhishen, Zhu, Zhongguo
• Format: Article
• Language: English
• Subjects: Basalt; Basalt fiber-reinforced polymer (BFRP); Creep (materials); Creep strain; Fiber reinforced plastics; Mathematical models; Modeling; Prestressing; Pretension; Strain; Strain rate; Tendons
• ISSN: 0264-1275; 1873-4197
• DOI: 10.1016/j.matdes.2015.10.090

Basalt fiber-reinforced polymer (BFRP) is a superior material for prestressing applications owing to its high creep rupture stress of 0.6 fu (fu=tensile strength). This paper proposes a method by pretension to further control the creep strain and lower prestressing loss of BFRP tendons serving as prestressed structural member. Experimental parameters including pretension levels and durations were selected to investigate their effects on creep strain control while creep strain rates and relevant variations were compared among the specimens under different control conditions. Furthermore, the modeling of long-term creep behavior based on a semi-logarithmic equation was also conducted. The results show that the pretension can significantly lower the creep strain of BFRP tendons. The maximum control effect of creep strain can be obtained by a pretension of 0.6 fu with duration of 3h. The above control effects are consistent with the results revealed by the residual strength of the specimens after creep test. The modeling prediction indicates that the creep strain rates at one thousand and one million hours for the BFRP tendon can be controlled to 1.46% and 3.65% under a sustained stress of 0.5 fu. [Display omitted] •Pretension can significantly lower creep strain of tendon by straightening fibers.•Pretension with 60% of strength and duration of 3h are the most effective.•After pretension the tendon meets requirement of prestressing application.