Mechanical property evolution and life prediction of carbon fiber and pultruded carbon fiber reinforced polymer plate exposed to elevated temperatures

2020 ◽  
Vol 41 (12) ◽  
pp. 5143-5155
Author(s):  
Chenggao Li ◽  
Guijun Xian

2019 ◽  
Vol 14 ◽  
pp. 155892501985001 ◽  
Author(s):  
Chenggao Li ◽  
Guijun Xian

The elevated temperature resistance and even fire resistance of carbon fiber-reinforced polymer composites were critical concerns in many applications. These properties of a carbon fiber-reinforced polymer depend not only on the degradation of the polymer matrix but also on that of the carbon fibers under elevated temperatures. In this study, influences of elevated temperatures (by 700°C for 30 min) in air on the mechanical properties and microstructures of a carbon fiber were investigated experimentally. It was found that the tensile strength and modulus as well as the diameters of the carbon fibers were reduced remarkably when the treatment temperatures exceeded 500°C. At the same time, the content of the structurally ordered carbonaceous components on the surface of carbon fibers and the graphite microcrystal size were reduced, while the graphite interlayer spacing ( d002) was enhanced. The deteriorated tensile modulus was attributed to the reduced graphite microcrystal size and the reduced thickness of the skin layer of the carbon fiber, while the degraded tensile strength was mainly attributed to the weakened cross-linking between the graphite planes.



2020 ◽  
Vol 23 (8) ◽  
pp. 1644-1655
Author(s):  
Zongquan Liu ◽  
Qingrui Yue ◽  
Rong Li ◽  
Xiaobing Chen

Carbon-fiber-reinforced polymer grids encased with polymer mortar have received much attention lately as an effective technology for strengthening concrete structures. The objective of this study was to investigate the bond-slip behavior of carbon-fiber-reinforced polymer grids to polymer mortar at room and elevated temperatures. First, 20 pull-out specimens were tested at room temperature of 20°C, and the investigated parameters included the type of carbon-fiber-reinforced polymer grids, the embedment length of longitudinal bar, and the transverse bar length. Based on the experimental results, a two-branch bond-slip model at room temperature was proposed, with the characteristic bond stress and the corresponding slip determined by the regression analysis of test data. Second, 24 pull-out specimens were tested at elevated temperatures over a range of 20°C–300°C, and the investigated parameters included the type of carbon-fiber-reinforced polymer grids and the testing temperature. Based on the experimental results, a bond-slip model at elevated temperatures was further proposed by modeling the temperature-dependent reduction factors. The two proposed bond-slip models will be particularly useful in the theoretical analysis of structures with carbon-fiber-reinforced polymer grids and polymer mortar strengthening system under both room and elevated temperatures.





PCI Journal ◽  
2014 ◽  
Vol 59 (1) ◽  
pp. 103-113 ◽  
Author(s):  
Clayton A. Burningham ◽  
Chris P. Pantelides ◽  
Lawrence D. Reaveley


2019 ◽  
Vol 7 (1) ◽  
pp. 30-34
Author(s):  
A. Ajwad ◽  
U. Ilyas ◽  
N. Khadim ◽  
Abdullah ◽  
M.U. Rashid ◽  
...  

Carbon fiber reinforced polymer (CFRP) strips are widely used all over the globe as a repair and strengthening material for concrete elements. This paper looks at comparison of numerous methods to rehabilitate concrete beams with the use of CFRP sheet strips. This research work consists of 4 under-reinforced, properly cured RCC beams under two point loading test. One beam was loaded till failure, which was considered the control beam for comparison. Other 3 beams were load till the appearance of initial crack, which normally occurred at third-quarters of failure load and then repaired with different ratios and design of CFRP sheet strips. Afterwards, the repaired beams were loaded again till failure and the results were compared with control beam. Deflections and ultimate load were noted for all concrete beams. It was found out the use of CFRP sheet strips did increase the maximum load bearing capacity of cracked beams, although their behavior was more brittle as compared with control beam.



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