scholarly journals Study of the Bond Capacity of FRCM- and SRG-Masonry Joints

CivilEng ◽  
2021 ◽  
Vol 2 (1) ◽  
pp. 68-86
Author(s):  
Karrar Al-Lami ◽  
Tommaso D’Antino ◽  
Pierluigi Colombi
Keyword(s):  
Fiber Reinforced Polymer ◽  
Fiber Reinforced ◽  
Shear Tests ◽  
Bond Behavior ◽  
Bond Performance ◽  
Direct Shear Tests ◽  
Reinforced Polymer ◽  
Inorganic Substrates ◽  
Externally Bonded ◽  
Steel Cord

Fiber-reinforced cementitious matrix (FRCM) and steel-reinforced grout (SRG) have been increasingly applied as externally bonded reinforcement to masonry members in the last few years. Unlike fiber-reinforced polymer (FRP), FRCM and SRG have good performance when exposed to (relatively) high temperature and good compatibility with inorganic substrates, and they can be applied to wet surfaces and at (reasonably) low temperatures. Although numerous studies investigated the mechanical properties and bond performance of various FRCM and SRG, new composites have been developed recently, and their performance still needs to be assessed. In this study, the bond behavior of three FRCM composites and one SRG composite applied to a masonry substrate is investigated. Sixteen single-lap direct shear tests (four tests for each composite) are performed. The FRCM studied comprised one layer of carbon, PBO (polyparaphenylene benzobisoxazole), or alkali-resistant (AR)-glass bidirectional textile embedded within two cement-based matrices. The SRG composite comprised one layer of a unidirectional stainless-steel cord textile embedded within a lime-based matrix. The results show a peculiar bond behavior and failure mode for each composite. Based on these results, the behavior of the carbon and PBO FRCM is modeled solving the bond differential equation with a trilinear cohesive material law (CML).

Recent developments in experimental and computational studies of hygrothermal effects on the bond between FRP and concrete

2020 ◽  
Vol 39 (11-12) ◽  
pp. 422-442 ◽  
Author(s):  
Faisal M Mukhtar ◽  
Olaniyi Arowojolu
Keyword(s):  
Experimental Testing ◽  
Fiber Reinforced Polymer ◽  
Effect Of Temperature ◽  
Polymer Concrete ◽  
Fiber Reinforced ◽  
Bond Performance ◽  
Reinforced Polymer ◽  
Temperature And Humidity ◽  
Externally Bonded ◽  
New Research

The performance of fiber reinforced polymer externally bonded to concrete is greatly influenced by the environmental conditions to which it is exposed during service. Temperature and humidity are the two common environmental factors that alter the bond behavior of externally bonded fiber reinforced polymer. This paper reviews the experimental and computational approaches used to evaluate the hygrothermal effects—that is, the effect of temperature and humidity—on the durability of the fiber reinforced polymer–concrete bond, as well as on the bond’s performance under loading conditions. Some experimental testing conducted in the laboratory and in situ are critically reviewed and presented. Implemented approaches for improving bond performance under hygrothermal conditions and their modeling techniques are also presented. The paper concludes by discussing the review’s salient issues. The ongoing wide application of externally bonded fiber reinforced polymer creates opportunities for new research on improving and predicting the bond strength of fiber reinforced polymer concrete under hygrothermal conditions.

scholarly journals Effect of Subtropical Natural Exposure on the Bond Behavior of FRP-Concrete Interface

Polymers ◽  
2020 ◽  
Vol 12 (4) ◽  
pp. 967 ◽  
Author(s):  
Xinyan Guo ◽  
Shenyunhao Shu ◽  
Yilin Wang ◽  
Peiyan Huang ◽  
Jiaxiang Lin ◽  
...  
Keyword(s):  
Shear Stress ◽  
Maximum Shear Stress ◽  
Exposure Period ◽  
Fiber Reinforced Polymer ◽  
Fiber Reinforced ◽  
Bond Behavior ◽  
Reinforced Polymer ◽  
Natural Exposure ◽  
Externally Bonded ◽  
Concrete Interface

Subtropical natural exposure may significantly affect the bonding behavior of fiber reinforced polymer (FRP) externally bonded to concrete. To study the effect of subtropical natural climates on the FRP-concrete interface, natural exposure tests and an analytical approach were carried out on specimens externally bonded with carbon fiber reinforced polymer (CFRP) and basalt fiber reinforced polymer (BFRP). The bilinear bond stress-slip relationships for different exposure periods were derived from the experimental results of the strengthened reinforced concrete (RC) beams. Based on these bond-slip relationships, the full-range behavior of shear stress along the bond length and debonding load can be obtained through the analytical solution. The testing and numerical results showed that subtropical natural exposure can greatly affect the bond behavior of CFRP-concrete and BFRP-concrete interfaces in the early exposure period. In the late exposure period, the bond behavior was basically stable. With the increase of exposure time, the position of maximum shear stress tended to move backward, which indicated that the behavior of the FRP-concrete interface was weakened by natural exposure. Compared to the CFRP-concrete interface, subtropical natural exposure has greater influence on the bond behavior of the BFRP-concrete interface.

Bond performance of GFRP and deformed steel hybrid bar with sand coating to concrete

2016 ◽  
Vol 36 (6) ◽  
pp. 464-475 ◽  
Author(s):  
Minkwan Ju ◽  
Gitae Park ◽  
Sangyun Lee ◽  
Cheolwoo Park
Keyword(s):  
Glass Fiber ◽  
Modulus Of Elasticity ◽  
Fiber Reinforced Polymer ◽  
Fiber Reinforced ◽  
Glass Fiber Reinforced Polymer ◽  
Bond Performance ◽  
Polymer Hybrid ◽  
Reinforced Polymer ◽  
Glass Fiber Reinforced ◽  
Steel Bar

In this study, we experimentally investigated the bond performance of a glass fiber-reinforced polymer hybrid bar with a core section comprising a deformed steel bar and a sand coating. The glass fiber-reinforced polymer and deformed steel hybrid bar (glass fiber-reinforced polymer hybrid bar) can contribute to longer durability and better serviceability of reinforced concrete members because of the increased modulus of elasticity provided by the deformed steel bar. Uniaxial tensile tests in compliance with ASTM D 3916 showed that the modulus of elasticity of the glass fiber-reinforced polymer hybrid bar was enhanced up to three times. For the bond test, a total of 30 specimens with various sand-coating and surface design parameters such as the size of the sand particles (0.6 mm and 0.3 mm), sand-coating type (partially or completely), number of strands of fiber ribs (6 and 10), and pitch space (11.4 mm to 29.1 mm) of the fiber ribs were tested. The completely sand-coated glass fiber-reinforced polymer hybrid bar exhibited a higher bond strength (90.5%) than the deformed steel bar and a reasonable mode of failure in concrete splitting. A modification parameter to the Eligehausen, Popov, and Bertero (BPE) model is suggested based on the representative experimental tests. The bond stress–slip behavior suggested by the modified BPE model in this study was in reasonable agreement with the experimental results.

Experimental study on the behavior of carbon fiber reinforced polymer sheets bonded to concrete

2006 ◽  
Vol 33 (11) ◽  
pp. 1438-1449 ◽  
Author(s):  
Ayman S Kamel ◽  
Alaa E Elwi ◽  
Roger J.J Cheng
Keyword(s):  
Carbon Fiber ◽  
Failure Mechanism ◽  
Test Method ◽  
Fiber Reinforced Polymer ◽  
Carbon Fiber Reinforced Polymer ◽  
Fiber Reinforced ◽  
Bond Behavior ◽  
Cfrp Sheets ◽  
Reinforced Polymer ◽  
Carbon Fiber Reinforced

This paper presents a study on the interfacial behavior of carbon fiber reinforced polymer (CFRP) sheets when applied to concrete members as external reinforcement. Two bond test methods that are detailed in the paper were used in separate test series to study the bond behavior and failure mechanism of CFRP sheets bonded to concrete. A modified push-apart test method was proposed and tested. It was concluded that there existed an effective length beyond which there will be no increase in the ultimate capacity of the joint. An experimental test method to determine the effective bond length was also proposed and tested. The strains at the edge of the CFRP sheets are consistently higher than those at the center. The anchorage requirements for the CFRP sheets were also investigated in this study. Anchor sheets placed at 90° to the primary test sheets and bonded underneath the tested sheet showed better or equivalent overall bond behavior compared with those bonded on top of the tested sheet. The distance at which the anchor sheet is placed from the crack does not appear to change the bond behavior.Key words: bond, concrete, debonding, failure mechanism, carbon fiber reinforced polymer (CFRP) sheets, anchor sheets.

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