scholarly journals Improving the Adhesion of BFRP Strips to the Concrete Surface

2019 ◽  
Vol 2 (2) ◽  
pp. 220-228
Author(s):  
Hasan Hüseyin Akbalık ◽  
Ali Sarıbıyık

Fiber Reinforced Polymer (FRP) composites are widely used in repair and strengthening of reinforced concrete structural elements. The FRP composite adhered to the concrete surface may be separated from the concrete surface in the form of debonding before reaching the ultimate strength. Epoxy resin, concrete strength, fiber properties and application method have an important role in bonding of FRP composites to concrete surfaces. In this study, concrete beam specimens were produced in order to investigate the adhesion of Basalt Fiber Reinforced Polymer (BFRP) composites to the concrete surface using conventional concretes. Stress distribution between concrete and BFRP was investigated by opening a gap in the bottom center of the samples. Unidirectional basalt fiber fabric was used in the production of the test specimens. The effects of concrete surface properties and U winding method on the end of fiber adhesion ability were investigated by bonding BFRP composite to the lower surfaces of the Specimens. Specimens were tested by four point bending experiment. According to the results obtained, the grinding of the concrete surface and the U-winding method significantly improve the adhesion.”

2017 ◽  
Vol 2017 ◽  
pp. 1-9 ◽  
Author(s):  
Yongmin Yang ◽  
Zhaoheng Li ◽  
Tongsheng Zhang ◽  
Jiangxiong Wei ◽  
Qijun Yu

Basalt Fiber Reinforced Polymer (BFRP) bars have bright potential application in concrete structures subjected to marine environment due to their superior corrosion resistance. Available literatures mainly focused on the mechanical properties of BFRP concrete structures, while the bond-slip behavior of BFRP bars, which is a key factor influencing the safety and service life of ocean concrete structures, has not been clarified yet. In this paper, effects of BFRP bars size, corrosion age, and concrete strength on the bond-slip behavior of BFRP bars in concrete cured in artificial seawater were investigated, and then an improved Bertero, Popov, and Eligehausen (BPE) model was employed to describe the bond-slip behavior of BFRP bars in concrete. The results indicated that the maximum bond stress and corresponding slip decreased gradually with the increase of corrosion age and size of BFRP bars, and ultimate slip also decreased sharply. The ascending segment of bond-slip curve tends to be more rigid and the descending segment tends to be softer after corrosion. A horizontal end in bond-slip curve indicates that the friction between BFRP bars and concrete decreased sharply.


2017 ◽  
Vol 747 ◽  
pp. 342-349 ◽  
Author(s):  
Mattia Santandrea ◽  
Giovanni Quartarone ◽  
Christian Carloni ◽  
Xiang Lin Gu

The rehabilitation of existing masonry elements by means of jacketing of columns using composite materials is becoming a remarkable technique in several applications that aim to increase the strength of existing masonry buildings. Fiber reinforced cementitious matrix (FRCM) composites are a newly developed strengthening system that consist of high-strength fibers embedded in a cementitious grout and externally bonded to the substrate. High resistance to fire and high temperatures, ease of handling during application, and vapor permeability with the substrate are some of the characteristics that make FRCMs a promising alternative to traditional organic composites such as fiber reinforced polymer (FRP) composites. This work presents the results of an experimental study carried out to understand the behavior of masonry columns with a square cross-section confined by steel and basalt fiber sheets embedded in a mortar matrix subjected to monotonic concentric compressive load. The effectiveness of the confinement is studied in terms of load-bearing capacity with respect to unconfined columns. The effect of corner radius for columns confined with basalt fibers is investigated.


2003 ◽  
Vol 1819 (1) ◽  
pp. 378-384 ◽  
Author(s):  
Vimala Shekar ◽  
Samer H. Petro ◽  
Hota V. S. GangaRao

Fiber-reinforced polymer (FRP) composites have been used more often over the past decade than before in new construction as well as in repair of deteriorated bridges. Many of these bridges are on low-volume roads, where they receive very little attention. It is imperative that new bridge construction or repair be long lasting, nearly maintenance free, and as economical as possible. Relative to those factors, FRP composite bridges have been found to be structurally adequate and feasible because of their reduced maintenance cost and limited environmental impact (i.e., no harmful chemicals leaching into the atmosphere with longer service life). In West Virginia, 23 FRP composite bridges have been constructed, among which 18 are built on low-volume roads that have an average daily traffic (ADT) of less than 1,000, including 7 with ADT less than 400. General FRP composite bridge geometry and preliminary field responses are presented as are some of the preliminary construction specifications and cost data of FRP composite bridges built on low-volume roads in West Virginia


Author(s):  
Jie Han ◽  
J. David Frost ◽  
Vicki L. Brown

Conventional pile materials, such as steel, concrete, and wood, can encounter serious corrosion problems in industrial and marine environments. Deterioration of steel, concrete, and wood piling systems has cost the military and civilian marine and waterfront civil engineering communities billions of dollars to repair and replace. Fiber-reinforced polymer (FRP) composites have desirable properties for extreme environments because they are noncorrosive, nonconductive, and lightweight. Different types of FRP composite piles are currently under research investigation, and some have been introduced to the marketplace. FRP composites have been used as internal reinforcement in concrete piles; as external shells for steel, concrete, and timber piles; and as structural piles such as FRP pipe piles, reinforced plastic piles, and plastic fender piles. The different ways of constituting FRP composite piles result in different behavioral effects. Because FRP structural piles have anisotropic properties, low section stiffness, and high ratios of elastic to shear modulus, they have different behavior in load-displacement relations under vertical and lateral loads. Current design methods for conventional piles were examined to determine the validity for FRP composite piles, and some new design methods specific to FRP structural piles were developed from research work conducted by the authors.


Polymers ◽  
2021 ◽  
Vol 13 (16) ◽  
pp. 2585
Author(s):  
Karolina Ogrodowska ◽  
Karolina Łuszcz ◽  
Andrzej Garbacz

This paper presents fiber-reinforced polymer composites which were modified by fibers hybridization as well as matrix nanomodifiaction with nanosilica. The article analyzed the nanosilica matrix modification and basalt-carbon hybridization’s effect on key properties of composites use as the main reinforcement in concrete structures. The comparative analysis was based on results of bars strength parameters determined in a shear test with the ASTM standard. The tests were performed for three bar diameters at room temperature and pre-heated FRP composites at 80 °C and 200 °C for 2 h with the aim of verifying the influence of the fiber hybridization-basalt-carbon fiber-reinforced polymer (HFRP) bars and the effect of nanosilica modification of the epoxy matrix (nHFRP). The test results were also compared with results of the shear test carried out after the bars were heated to 80 °C for 30 min in order to verify and evaluate the effect of the heating time. These types of tests are relevant to the conditions that occur in FRP composites when exposed to elevated temperatures.


Materials ◽  
2020 ◽  
Vol 13 (8) ◽  
pp. 1898
Author(s):  
Marek Urbański

A new type of HFRP hybrid bars (hybrid fiber reinforced polymer) was introduced to increase the rigidity of FRP reinforcement, which was a basic drawback of the FRP bars used so far. Compared to the BFRP (basalt fiber reinforced polymer) bars, modification has been introduced in HFRP bars consisting of swapping basalt fibers with carbon fibers. One of the most important mechanical properties of FRP bars is compressive strength, which determines the scope of reinforcement in compressed reinforced concrete elements (e.g., column). The compression properties of FRP bars are currently ignored in the standards (ACI, CSA). The article presents compression properties for HFRP bars based on the developed compression test method. Thirty HFRP bars were tested for comparison with previously tested BFRP bars. All bars had a nominal diameter of 8 mm and their nonanchored (free) length varied from 50 to 220 mm. Test results showed that the ultimate compressive strength of nonbuckled HFRP bars as a result of axial compression is about 46% of the ultimate strength. In addition, the modulus of elasticity under compression does not change significantly compared to the modulus of elasticity under tension. A linear correlation of buckling load strength was proposed depending on the free length of HFRP bars.


2010 ◽  
Vol 168-170 ◽  
pp. 549-552
Author(s):  
Yan Lei Wang ◽  
Qing Duo Hao ◽  
Jin Ping Ou

A new form of fiber reinforced polymer (FRP)-concrete composite beam is proposed in this study. The proposed composite beam consists of a GFRP box beam combined with a thin layer of concrete in the compression zone. The interaction between the GFRP beam and the concrete was obtained by bonding coarse-sand on the top flange of the GFRP beam. One GFRP box beam and one GFRP-concrete composite beam were investigated in four-point bending test. Load-deflection response, mid-span longitudinal strain distributions and interface slip between GFRP beam and the concrete for the proposed composite beam were studied. Following conclusions are drawn from this study: (1) the stiffness and strength of the composite beam has been significantly increased, and the cost-to-stiffness ratio of the composite beam has been drastically reduced comparing with GFRP-only box beam; (2) a good composite action has been achieved between the GFRP beam and the concrete; (3) crushing of concrete in compression defines flexural collapse of the proposed composite beam..


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.


2021 ◽  
pp. 136943322110585
Author(s):  
Seyed Mehrdad Elhamnike ◽  
Rasoul Abbaszadeh ◽  
Vahid Razavinasab ◽  
Hadi Ziaadiny

Exposure of buildings to fire is one of the unexpected events during the life of the structure. The heat from the fire can reduce the strength of structural members, and these damaged members need to be strengthened. Repair and strengthening of concrete members by fiber-reinforced polymer (FRP) composites has been one of the most popular methods in recent years and can be used in fire-damaged concrete members. In this paper, in order to provide further data and information about the behavior of post-heated circular concrete columns confined with FRP composites, 30 cylindrical concrete specimens were prepared and subjected under four exposure temperatures of 300, 500, 700, and 900. Then, specimens were repaired by carbon fiber reinforced polymer composites and tested under axial compression. Results indicate that heating causes the color change, cracks, and weight loss of concrete. Also, with the increase of heating temperature, the shape of stress–strain curve of FRP-retrofitted specimens will change. Therefore, the main parts of the stress–strain curve such as ultimate stress and strain and the elastic modulus will change. Thus, a new stress–strain model is proposed for post-heated circular concrete columns confined by FRP composites. Results indicate that the proposed model is in a good agreement with the experimental data.


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