scholarly journals Study of the Interfacial Bond Behavior between CFRP Grid–PCM Reinforcing Layer and Concrete via a Simplified Mechanical Model

Materials ◽  
2021 ◽  
Vol 14 (22) ◽  
pp. 7053
Author(s):  
Huijuan Dai ◽  
Bo Wang ◽  
Jiawei Zhang ◽  
Junlei Zhang ◽  
Kimitaka Uji
Keyword(s):  
Mechanical Model ◽  
Test Results ◽  
Interfacial Bond ◽  
Bond Behavior ◽  
Pull Out ◽  
Interface Bond ◽  
Reinforcing Layer ◽  
Bond Mechanism ◽  
Grid Interval ◽  
Simplified Mechanical Model

This paper presents the results of pull-out tests conducted to investigate the interfacial bond behavior between a carbon-fiber-reinforced polymer (CFRP) grid–polymer cement mortar (PCM) reinforcing layer and existing concrete, and proposes a simplified mechanical model to further study the interface bond mechanism. Four specimens composed of a CFRP grid, PCM, and concrete were tested. The influence of the type of CFRP grid and the grid interval on the interface bond behavior was discussed. The failure patterns, maximum tensile loads, and CFRP grid strains were obtained. The change process of interface bond stress was investigated based on the grid strain analysis. In addition, the simplified mechanical model and finite element model (FEM) were emphatically established, and the adaptability of the simplified mechanical model was validated through the comparative analysis between the FEM results and the test results. The research results indicate that a CFRP grid with a larger cross-sectional area and smaller grid interval could effectively improve the interface bond behavior. The tensile stress was gradually transferred from the loaded edge to the free edge in the CFRP grid. The interface bond behavior was mainly dependent on the anchorage action of the CFRP grid in the PCM, and the bond action between the PCM and the concrete. The FEM results were consistent with the test results, and the simplified mechanical model with nonlinear springs could well describe the interface bond mechanism between the CFRP grid–PCM reinforcing layer and concrete.

scholarly journals The Comparison of Bond Strength between Geopolymer Concrete and OPC Concrete for Plain Reinforcing Bars

2018 ◽  
Vol 159 ◽  
pp. 01017 ◽  
Author(s):  
Nuroji ◽  
Daniel Herdian Primadyas ◽  
Ilham Nurhuda ◽  
Muslikh
Keyword(s):  
Bond Strength ◽  
Geopolymer Concrete ◽  
Test Results ◽  
Reinforcing Bars ◽  
Normal Concrete ◽  
Steam Power ◽  
Bond Behavior ◽  
Pull Out ◽  
Concrete Blocks ◽  
Class F Fly Ash

This paper describes the research on bond behavior of plain reinforcing bars in geopolymer and normal concrete. The geopolymer concrete in this research was made of class F fly ash taken from Tanjung Jati Electric Steam Power Plant (PLTU) with Sodium Hydroxide (NaOH) and Sodium Silicate (Na2SiO3) as alkaline activator, added in the mixture. The effect of bar size was studied by varying the bar diameter in range 10 mm to 19 mm. Each bar was casted in the center of concrete blocks made of geopolymer as well as normal concrete. Pull-out tests were carried out to the specimens that have reached 28 days of age. The test results show that the bond behavior of geopolymer concrete differs substantially from normal concrete, where geopolymer concrete has a higher bond strength when compared to normal concrete with identical concrete strengths.

scholarly journals Experimental Study on Interfacial Bond Behavior between CFRP Sheets and Steel Plates under Fatigue Loading

Materials ◽  
2019 ◽  
Vol 12 (3) ◽  
pp. 377 ◽  
Author(s):  
Long Zhang ◽  
Shuangyin Cao ◽  
Xin Tao
Keyword(s):  
Stress Level ◽  
Fatigue Behavior ◽  
Steel Structures ◽  
Fatigue Loading ◽  
Development Rate ◽  
Crack Development ◽  
Strengthening Effect ◽  
Test Results ◽  
Interfacial Bond ◽  
Bond Behavior

Using carbon fiber reinforced polymer (CFRP) composites for enhancing the fatigue behavior of the steel structures will be an important application. As the most critical part, the fatigue behavior of the CFRP-to-steel bonded interface directly determines the strengthening effect of steel structures reinforced by CFRP. In this paper, a series of CFRP-to-steel double-shear specimens are performed in order to study the interfacial bond behavior between CFRP and steel under fatigue loading. Two parameters are considered: the upper bound value and the lower bound value of the fatigue loading. An analysis of test results indicates that the crack development rate increases with the increment of the stress ratio or stress level and the crack development process includes two phases: crack stable development phase and debonding failure phase. A calculation model is put forward to describe the relationship between the crack development rate and the stress level. Besides, it can be obtained from the test results that the fatigue lives of the specimens decrease with the increment of the stress level. The empirical formula of S-N curve based on the form of single logarithm formula is proposed and the fatigue limit under the experimental conditions in this paper is determined to be 0.343 by computational analysis.

Bond Behavior of Low-Activated High Aluminate Concrete with Reinforcement under Cyclic Load

2019 ◽  
Vol 972 ◽  
pp. 34-39
Author(s):  
Yu Cheng Kan ◽  
Kuang Chih Pei ◽  
Wei Lin Hsu
Keyword(s):  
Compressive Strength ◽  
Static Loading ◽  
Cyclic Load ◽  
Ultimate Load ◽  
High Alumina ◽  
Test Results ◽  
Normal Concrete ◽  
Bond Behavior ◽  
Pull Out ◽  
Emission Monitoring

The bond behavior of reinforcement and low-activated concrete (LAC) was investigated in this study. The acoustic emission monitoring was also engaged while the specimen being loaded to figure out the inside fracture. Static loading and dynamic loading were applied for both of the LAC and normal concrete in the pull-out tests. The upper load was applied starting from 30% of the static ultimate load Pu with a 10% increment until the failure. The loading frequencies for the test were 0.5 Hz、1.0 Hz and 2.0 Hz. The bond stiffness after each stage of dynamical loads was examined. Test results reveal that the LAC performs higher compressive strength than normal concrete for a given W/C ratio. But, the bond strength of LAC seems not promotes correspondingly. It may be attributed to the conversion effect of high alumina contained in LAC, which leads to more voids inside the concrete.

Influence of Fiber Embedded Length on Properties of Single Fiber Pull-Out Test

2014 ◽  
Vol 919-921 ◽  
pp. 2061-2070
Author(s):  
Ya Fang Zhang ◽  
Pei Ran Chen ◽  
Hao Liu ◽  
Qing Hua Wu
Keyword(s):  
Bond Strength ◽  
Numerical Models ◽  
Polypropylene Fiber ◽  
Fiber Reinforced Concrete ◽  
Single Fiber ◽  
Test Results ◽  
Interfacial Bond ◽  
Interfacial Bond Strength ◽  
Pull Out ◽  
Damage Process

The reinforcing and toughening effect of fiber reinforced concrete (FRC) are mainly under control of the interfacial bond strength in between of fiber and concrete, and the embedded length of fiber is one of the significant factors for interfacial bond strength. In this paper, pull-out numerical models based on single steel or polypropylene fiber have been studied with the fiber embedded length set as a variable and the influence of fiber embedded length on properties of single fiber pullout has, therefore, been analyzed. The results indicate that the longer the fiber embedded length, the larger the peak index and pull-out toughness of single fiber pull-out specimen could be reached, while the interfacial bond strength would decrease. The variation of fiber embedded length has only a little impact upon the damage process of pullout. Finally, the test results for specimen with the polypropylene fiber is more sensitive to the changes of embedded length compared those with steel fiber

Bond Behavior of Aluminum Laminates in NSM Technique

2014 ◽  
Vol 501-504 ◽  
pp. 1053-1060 ◽  
Author(s):  
Ji Hua Zhu ◽  
Miao Chang Zhu ◽  
Liang Liang Wei ◽  
Wei Wen Li ◽  
Feng Xing
Keyword(s):  
Bond Length ◽  
Applied Force ◽  
Fiber Reinforced Polymer ◽  
Test Results ◽  
Interfacial Bond ◽  
Bond Behavior ◽  
Reinforced Polymer ◽  
Measured Strain ◽  
Average Bond ◽  
Nsm Technique

An attempt was made to replace the commonly used Fiber Reinforced Polymer (FRP) with aluminium alloy in NSM technique. This paper presents experimental investigation of interfacial bond behavior between NSM aluminium laminates and concrete structures. Aluminum laminates were mounted into premade slit of concrete with epoxy resin. Test results show that both maximum applied force and ductility of NSM reinforced specimens can be effectively improved by increasing bond length and width of aluminium laminates, whilst almost no change was found in average bond strength at the same time. Besides, the loaded end slip of specimen, corresponding to the maximum applied force, was mutually influenced by bond length and width of aluminium laminates. Furthermore, the measured strain distribution of aluminium laminates along the direction of bond length of specimen was found to be similar to that of FRP in NSM technique.

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.

Experimental Research on Interfacial Bond Performance in Rock Anchor with High-Performance Grouting Medium

2012 ◽  
Vol 517 ◽  
pp. 932-938 ◽  
Author(s):  
Zhi Fang ◽  
Hong Qiao Zhang
Keyword(s):  
Rock Mass ◽  
Bond Strength ◽  
High Performance ◽  
Interfacial Bond ◽  
Interfacial Bond Strength ◽  
Bond Performance ◽  
Pull Out ◽  
Steel Bar ◽  
Reactive Powder ◽  
Ground Anchor

There exist the problems such as low bond strength and bad durability in the ordinary grouting slurry of the ground anchor system at present. The high-performance grouting mediums RPC (Reactive Powder Concrete) and DSP (Densified Systems containing homogeneously arranged ultrafine Particles) would become the potential replacement of grouting medium in ground anchor resulting from their high compressive strength, durability and toughness. Based on a series of pull-out tests on ground anchors with different high-performance grouting medium of RPC and DSP , different bond length in the construction field, the bond performance on the interfaces between anchor bolt (deformed steel bar) and grouted medium as well as between grouted medium and rock mass was studied. The results indicate that the interfacial bond strength between RPC or DSP and deformed steel bolt ranges within 23-31Mpa, far greater than that (about 2-3MPa) between the ordinary cementitious grout and deformed steel bar. Even though the interfacial bond strength between the grouted medium and rock mass of limestone was not obtained in the test since the failure mode was pull-out of those steel bar rather than the interface shear failure between grouted medium and rock mass, the bond stress on the interface reached 6.2-8.38 MPa, also far greater than the bond strength (about 0.1-3MPa) between the ordinary cementitious slurry and rocks.

Size Effect on the Bond Behavior of Grouted Reinforcing Bars Embedded in Light-weight Concrete

2021 ◽  
Author(s):  
Aamer Abbas ◽  
◽  
Yaqoob Yaqoob ◽  
Ola Hussein ◽  
Ibrahim Al-Ani ◽  
...  
Keyword(s):  
Bond Strength ◽  
Concrete Specimen ◽  
Light Weight ◽  
Reinforcing Bars ◽  
Conventional Concrete ◽  
Bond Behavior ◽  
Pull Out ◽  
Specimen Width ◽  
Light Weight Concrete ◽  
The Relationship

This study presents experimentally the bond behavior of light-weight concrete specimens with grouted reinforcing bars in comparison with conventional concrete specimens. A total of (9) pull-out specimens were studied; (3) specimens of conventional concrete, (3) specimens of light-weight concrete, and other (3) specimens of grouted light-weight concrete. Two variables are adopted in this investigation: specimen width and type of concrete (conventional concrete, light-weight concrete and grouted light-weight concrete). The study contains a discussion of the general behavior of the specimens in addition to the study of the ultimate bond capacity, maximum bond stresses and the relationship between the stress and the slip for different pull-out specimens. Results show that bond strength is highest for the largest specimen size (bond strength of grouted light-weight concrete specimen with specimen width 400 mm is higher than that of the specimen with (200 mm) width by about (13.13%)). Also, bond strength is highest for the grouted light-weight concrete specimen (bond strength of grouted light-weight concrete specimen is higher than conventional concrete specimen by (11.11%)).

EFFECT OF WET-DRY CYCLING ON BOND BEHAVIOR OF GFRP STRENGTHENED HISTORIC MASONRY STRUCTURES

2016 ◽  
Vol 78 (5-2) ◽  
Author(s):  
Meng Jing ◽  
Werasak Raongjant
Keyword(s):  
Research Work ◽  
Fiber Reinforced Polymer ◽  
Masonry Structures ◽  
Test Results ◽  
Bond Behavior ◽  
Historic Masonry ◽  
Water Permeation ◽  
Reinforced Polymer ◽  
Glass Fiber Reinforced ◽  
Cycling Condition

The objective of this research work is to determine the effect of wet-dry cycling on bond behavior of historic masonry structures strengthened by Glass Fiber Reinforced Polymer (GFRP). Shear bond testing was carried out through total 36 specimens exposed to dry, full moisture or wet-dry cycling conditions.  The selected samples were then tested at 0, 30, 60 and 90 days. Post-ageing test was also preceded on total sixty masonry prisms exposed to dry, full moisture or wet-dry cycling conditions. The compressive strengths of selected samples were then tested at 0, 40, 70 and 100 days. The test results showed an obvious decrease of the bond strength between GFRP sheets and bricks in the wet-dry cycling condition. For masonry prisms with or without GFRP strengthening, in the first 40 days, the compressive strength of GFRP bonded prism decreased quickly to the value near that of prism without GFRP. After 40 days the rate of decrease became slow, which means that, sheets retrofitted outside the masonry prisms helped to improve their durability by reducing water permeation. 

Influence of Silane Coupling Agent on Interfacial Strength of SMA Composite

2010 ◽  
Vol 143-144 ◽  
pp. 933-937
Author(s):  
Yu Long Wang ◽  
Zhen Qing Wang ◽  
Li Min Zhou ◽  
Hai Tao Huang
Keyword(s):  
Coupling Agent ◽  
Shape Control ◽  
Silane Coupling Agent ◽  
Interfacial Strength ◽  
Test Results ◽  
Surrounding Matrix ◽  
Pull Out ◽  
Damage Repair ◽  
Silane Coupling ◽  
Epoxy Matrix Composite

Shape memory alloy (SMA) can be embedded into a host material to achieve shape control, damage repair and self-adaption. It is well recognized that the applications of SMA composites are highly dependent on the integrity of SMA fiber-matrix interface. However, the interfacial debonding often occurs due to the weak bonding of interface between the SMA wire and its surrounding matrix. Therefore, it is necessary to improve interfacial strength of SMA composites. In present paper, the epoxy resin is functionalized by mixing different amount of silane coupling agent to improve the interfacial adhesion of SMA fiber reinforced epoxy matrix composite. The single fiber pull-out test is carried out to evaluate the interfacial strength and the test results indicate that the interfacial strength of SMA composite is improved significantly as compared to the results from unfunctionalized samples.

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