Strain rate effect on bond stress–slip relationship between basalt fiber-reinforced polymer sheet and concrete

2015 ◽  
Vol 34 (7) ◽  
pp. 547-563 ◽  
Author(s):  
Dejian Shen ◽  
Xiang Shi ◽  
Yong Ji ◽  
Fenfang Yin
2017 ◽  
Vol 24 (6) ◽  
pp. 909-918 ◽  
Author(s):  
Muhammet Seis ◽  
Ahmet Beycioğlu

AbstractThis paper reports the results of an experimental investigation carried out to evaluate the bond stress behavior of basalt fiber-reinforced polymer (BFRP) bar and steel rebar (SR) in conventional C30-type concrete. The experimental program was conducted on testing 16 hinged beam specimens that were prepared according to BS 4449:2005+A2:2009 standard. Conventional C30-type concrete was used to produce hinged beams. In beam tests, bar diameter and embedment length were used as experimental variables. The bond performances of BFRP bar and SR were compared with the help of the load-slip results of hinged beam bending tests conducted on produced beam samples after 28 days of curing. Results showed that much higher bond stress values were obtained from BFRP bars compared to SR for both 12 and 8 mm bar diameters. Besides, the maximum bond stress values decreased with increasing bar diameter and embedment length for both BFRP bar and SR.


2018 ◽  
Vol 765 ◽  
pp. 355-360 ◽  
Author(s):  
Sakol Suon ◽  
Shahzad Saleem ◽  
Amorn Pimanmas

This paper presents an experimental study on the compressive behavior of circular concrete columns confined by a new class of composite materials originated from basalt rock, Basalt Fiber Reinforced Polymer (BFRP). The primary objective of this study is to observe the compressive behavior of BFRP-confined cylindrical concrete column specimens under the effect of different number of layers of basalt fiber as a study parameter (3, 6, and 9 layers). For this purpose, 8 small scale circular concrete specimens with no internal steel reinforcement were tested under monotonic axial compression to failure. The results of BFRP-confined concrete specimens of this study showed a bilinear stress-strain response with two ascending branches. Consequently, the performance of confined columns was improved as the number of BFRP layer was increased, in which all the specimens exhibited ductile behavior before failure with significant strength enhancement. The experimental results indicate the well-performing of basalt fiber in improving the concrete compression behavior with an increase in number of FRP layers.


2016 ◽  
Vol 51 (9) ◽  
pp. 1275-1284 ◽  
Author(s):  
Jianzhe Shi ◽  
Xin Wang ◽  
Huang Huang ◽  
Zhishen Wu

Relaxation is a key factor that controls the application of prestressing fiber-reinforced polymer tendons. This paper focuses on the evaluation of the relaxation behavior of newly developed basalt fiber-reinforced polymer tendons through an approach considering anchorage slippage. A series of relaxation tests on basalt fiber-reinforced polymer tendons subjected to three levels of initial stresses (0.4 fu, 0.5 fu, and 0.6 fu, where fu = ultimate strength) were conducted using a specially designed test setup that eliminates the impact of slippage at the anchor zone. An additional group of tests was conducted to validate the enhancement effect of pretension on the relaxation behavior. The relaxation rates at one million hours were predicted based on experimental fitting. Finally, the relaxation rates at 1000 h were predicted using the correlation between the relaxation and creep and were validated with the experimental relaxation rates. The results demonstrate the effectiveness of the proposed setup in measuring the relaxation loss of specimens and reveal that the relaxation rates of untreated basalt fiber-reinforced polymer tendons at 1000 h are 4.2%, 5.3%, and 6.4% at 0.4 fu, 0.5 fu, and 0.6 fu, respectively. Pretension treatment performs effective in relaxation loss controlling. BFRP tendons are recommended to be applied at an initial stress of 0.5 fu after pretension treatment, with one-million-hour relaxation rate equal to 6.7%. Furthermore, the relaxation rate at 1000 h can be predicted accurately based on the creep behavior. The conclusions of this study can provide guidance for the prestressing applications of basalt fiber-reinforced polymer tendons.


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