Bond behavior of fully bonded CFRP-concrete interface with improved double shear tests

2021 ◽  
pp. 102866
Author(s):  
Wen Li ◽  
Peiyan Huang ◽  
Zhanbiao Chen ◽  
Xiaohong Zheng ◽  
Yi Yang ◽  
...  
Keyword(s):  
Shear Tests ◽  
Bond Behavior ◽  
Double Shear ◽  
Concrete Interface

scholarly journals Experimental Study on Bond Behavior of FRP-Concrete Interface in Hygrothermal Environment

2016 ◽  
Vol 2016 ◽  
pp. 1-12 ◽  
Author(s):  
X. H. Zheng ◽  
P. Y. Huang ◽  
X. Y. Guo ◽  
J. L. Huang
Keyword(s):  
Interface Failure ◽  
Bond Behavior ◽  
Double Shear ◽  
Frp Composite ◽  
Temperature And Humidity ◽  
Carbon Fiber Laminate ◽  
Hygrothermal Environment ◽  
Displacement Transducers ◽  
Longitudinal Strains ◽  
Concrete Interface

As the technique of fiber-reinforced polymer (FRP) composite material strengthened reinforced concrete structures is widely used in the field of civil engineering, durability of the strengthened structures has attracted more attention in recent years. Hygrothermal environment has an adverse effect on the bond behavior of the interface between FRP and concrete. This paper focuses on the bond durability of carbon fiber laminate- (CFL-) concrete interface in hygrothermal condition which simulates the climate characteristic in South China. Twenty 100 mm × 100 mm × 720 mm specimens were divided into 6 groups based on different temperature and humidity. After pretreatment in hygrothermal environment, the specimens were tested using double shear method. Strain gauges bonded along the CFL surface and linear variation displacement transducers (LVDTs) were used to measure longitudinal strains and slip of the interface. Failure mode, ultimate capacity, load-deflection relationship, and relative slip were analyzed. The bond behavior of FRP-concrete interface under hygrothermal environment was studied. Results show that the ultimate bearing capacity of the interface reduced after exposure to hygrothermal environments. The decreasing ranges were up to 27.9% after exposure at high temperature and humidity (60°C, 95% RH). The maximum strains (εmax) of the specimens pretreated decreased obviously which indicated decay of the bond behavior after exposure to the hygrothermal environment.

scholarly journals Experimental Characterization of the FRCM-Concrete Interface Bond Behavior Assisted by Digital Image Correlation

Sensors ◽  
2021 ◽  
Vol 21 (4) ◽  
pp. 1154
Author(s):  
Dario De Domenico ◽  
Antonino Quattrocchi ◽  
Damiano Alizzio ◽  
Roberto Montanini ◽  
Santi Urso ◽  
...  
Keyword(s):  
Digital Image Correlation ◽  
Digital Image ◽  
Mechanical Tests ◽  
Image Correlation ◽  
Front Face ◽  
Full Field ◽  
Bond Behavior ◽  
Externally Bonded ◽  
Strengthening Technique ◽  
Concrete Interface

Digital Image Correlation (DIC) provides measurements without disturbing the specimen, which is a major advantage over contact methods. Additionally, DIC techniques provide full-field maps of response quantities like strains and displacements, unlike traditional methods that are limited to a local investigation. In this work, an experimental application of DIC is presented to investigate a problem of relevant interest in the civil engineering field, namely the interface behavior between externally bonded fabric reinforced cementitious mortar (FRCM) sheets and concrete substrate. This represents a widespread strengthening technique of existing reinforced concrete structures, but its effectiveness is strongly related to the bond behavior between composite fabric and underlying concrete. To investigate this phenomenon, a set of notched concrete beams are realized, reinforced with FRCM sheets on the bottom face, subsequently cured in different environmental conditions (humidity and temperature) and finally tested up to failure under three-point bending. Mechanical tests are carried out vis-à-vis DIC measurements using two distinct cameras simultaneously, one focused on the concrete front face and another focused on the FRCM-concrete interface. This experimental setup makes it possible to interpret the mechanical behavior and failure mode of the specimens not only from a traditional macroscopic viewpoint but also under a local perspective concerning the evolution of the strain distribution at the FRCM-concrete interface obtained by DIC in the pre- and postcracking phase.

scholarly journals Experimental and Numerical Investigation on the Steel Reinforced Grout (SRG) Composite-to-Concrete Bond

2020 ◽  
Vol 4 (4) ◽  
pp. 182
Author(s):  
Luciano Ombres ◽  
Salvatore Verre
Keyword(s):  
Bond Length ◽  
Failure Modes ◽  
Peak Load ◽  
Element Model ◽  
Test Results ◽  
Shear Tests ◽  
Bond Slip ◽  
Bond Behavior ◽  
Direct Shear Tests ◽  
Inorganic Matrix

In the paper, the bond between a composite strengthening system consisting of steel textiles embedded into an inorganic matrix (steel reinforced grout, SRG) and the concrete substrate, is investigated. An experimental investigation was carried out on medium density SRG specimens; direct shear tests were conducted on 20 specimens to analyze the effect of the bond length, and the age of the composite strip on the SRG-to-concrete bond behavior. In particular, the tests were conducted considering five bond length (100, 200, 250, 330, and 450 mm), and the composite strip’s age 14th, 21st, and 28th day after the bonding. Test results in the form of peak load, failure modes and, bond-slip diagrams were presented and discussed. A finite element model developed through commercial software to replicate the behavior of SRG strips, is also proposed. The effectiveness of the proposed numerical model was validated by the comparison between its predictions and experimental results.

Adhesion between SRP and Masonry: Influence of Moist Condition of Specimens and Presence of Salts in the Substrate

2019 ◽  
Vol 817 ◽  
pp. 182-188 ◽  
Author(s):  
Yu Yuan ◽  
Cristina Gentilini ◽  
Christian Carloni ◽  
Elisa Franzoni
Keyword(s):  
Ion Chromatography ◽  
Weak Link ◽  
New Technology ◽  
Shear Tests ◽  
Artificial Weathering ◽  
Bond Behavior ◽  
Lap Shear ◽  
Reinforced Polymer ◽  
Moist Condition

In recent years, steel reinforced polymer (SRP) composites have emerged as a new technology for structural strengthening, and several researches have validated the effectiveness of SRP for masonry strengthening. Research has been carried out to study the bond behavior of SRP composites applied to a masonry substrate. However, how the moist and salt on masonry surface will affect bond, which is the weak link in real strengthening applications, is little known yet. This study aims at investigating the bond behavior of SRP composites applied to moist and salt-laden masonry blocks that were subjected to an artificial weathering protocol. Single-lap shear tests were conducted to determine the bond behavior, while ion chromatography provided the salts distribution of weathered specimens to interpret some results of the shear tests.

Bond Behavior between Tuff and Fired-Clay Brick Masonry Blocks and SRG Composites

2019 ◽  
Vol 817 ◽  
pp. 118-125
Author(s):  
Giulia Baietti ◽  
Elisa Franzoni ◽  
Giovanni Quartarone ◽  
Alberto Fregni ◽  
Christian Carloni
Keyword(s):  
Salt Crystallization ◽  
Clay Brick ◽  
Shear Tests ◽  
Composite Matrix ◽  
Bond Behavior ◽  
Direct Shear Tests ◽  
Clay Bricks ◽  
Historical Structures ◽  
Salt Distribution ◽  
Masonry Units

This paper presents the results of single-lap direct shear tests on steel reinforced grout (SRG) strips bonded to fired-clay brick and tuff masonry blocks. For this experimental campaign, fifteen masonry blocks were constructed and reinforced with SRG composite strips. Fired-clay bricks and tuff blocks herein employed were collected from demolished historical structures in Modena and Naples (Italy), respectively. Eight out of fifteen blocks were subjected to an artificial weathering procedure to induce salt crystallization, and therefore reproduce the degradation conditions that the buildings could be subjected to during their life. Bond behavior of unconditioned strengthened specimens (i.e. SRG-masonry joints) was compared with the behavior of conditioned joints. Salt distribution, open porosity, and water absorption of brick and tuff masonry units as well as of the SRG composite matrix were analyzed to understand if and how the salt crystallization influenced the adhesion between the SRG strip and the block.

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