کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
6480636 | 1428759 | 2017 | 7 صفحه PDF | دانلود رایگان |
- 85 short-term and 15 creep pull-out tests are performed on polypropylene fibers.
- The embedded length and angle greatly influence the pull-out behavior.
- Post-peak pull-out is governed by the embossment profile of the fibers.
- Fiber creep is proposed to be the driving force behind pull-out creep.
This paper reports on the short-term and creep pull-out behavior of different polypropylene fibers from a concrete matrix. 85 displacement controlled tests are carried out for two types of fibers with different embedded lengths and angles. Additionally, 15 creep tests are performed in a climate controlled room at different load ratios to study long-term loading effects. The pull-out tests show that an increase in the embedded length of the fiber increases the maximum pull-out force. More inclined fibers with respect to the load application direction initially increase the pull-out force as well, but the fibers tend to rupture more at the concrete surface, leading to a brittle failure mode. Furthermore, an oscillating post-peak behavior is observed during pull-out which is related to the embossed surface profile of the fibers. The profile is gradually abraded during the test which in turn leads to a pure-friction controlled pull-out behavior at large relative displacements. The pull-out creep tests show that the behavior strongly depends on the load ratio, with higher loads decreasing the failure time. A novel positive feedback loop mechanism is proposed to qualitatively explain the pull-out creep behavior in which the fiber creep deformations are the driving force behind pull-out creep.
Journal: Construction and Building Materials - Volume 147, 30 August 2017, Pages 858-864