scholarly journals Bond Behavior between Concrete and Self-Expansion Polymer Material under Normal Pressures

2021 ◽  
Vol 2021 ◽  
pp. 1-15
Author(s):  
Xinxin Li ◽  
Fuming Wang ◽  
Hongyuan Fang ◽  
Dan Zheng ◽  
Yingchun Fu
Keyword(s):  
Bond Strength ◽  
Failure Modes ◽  
Concrete Strength ◽  
Normal Pressure ◽  
Element Model ◽  
Test Results ◽  
Shear Tests ◽  
Direct Shear Tests ◽  
Peak Point ◽  
Polymer Density

Self-expansion polymer grouting technology is a new rapid trenchless method for repairing leakage and subsidence of underground concrete structures. The bond between polymer and concrete is critical to determine the ultimate conditions of repaired concrete. In this paper, a series of direct shear tests were performed to investigate the influence of normal pressure on the shear bond properties between self-expansion polymer and concrete with different polymer density and concrete strength. Results indicate that failure modes and bond strength are greatly influenced by the normal pressure for specimens with a lower polymer density. For a given normal pressure, the bond strength linearly increases with the increasing polymer density. As the polymer density increased up to 0.43 g/cm3, the increased ratio decreases with the polymer density. Moreover, the displacement at the peak point reduces with an increase in polymer density. Finally, a finite element model is proposed to evaluate the bond strength for specimen failure in concrete and verified with the test results.

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.

An Experiment on Bond-Anchoring Property of Prestressing Spiral Groove Tendon

2011 ◽  
Vol 105-107 ◽  
pp. 1685-1688
Author(s):  
Meng Chen ◽  
Pin Wu Guan
Keyword(s):  
Yield Strength ◽  
Failure Modes ◽  
Concrete Strength ◽  
Concrete Cover ◽  
Tensile Yield Strength ◽  
Test Results ◽  
Statistical Regression ◽  
Spiral Groove ◽  
Anchoring Strength ◽  
Good Agreement

Prestressing spiral groove tendon is a new sort prestressing tendon, its characteristic value of tensile yield strength fyk=1000MPa. Firstly, the yield strength, ultimate tensile strength, elastic modulus and elongation are all tested. According to 68 pullout tests, the bond-anchoring curves and failure modes have been studied, and the effects of concrete strength, diameter, anchoring length, thickness of concrete cover and stirrup ratio have been all analyzed. Finally, the equation for ultimate bond-anchoring strength has been suggested by statistical regression, and the test results are in good agreement with values of the suggested equation.

Experimental Research on Durability of Concrete of Transmission Lines in Wuhu Area

2014 ◽  
Vol 1065-1069 ◽  
pp. 2001-2004
Author(s):  
Zhao Qing Zhu ◽  
Lin Xu ◽  
Jian Chen ◽  
Zhi Wei Han
Keyword(s):  
Bond Strength ◽  
Transmission Lines ◽  
Concrete Strength ◽  
Field Tests ◽  
Windward Side ◽  
Leeward Side ◽  
Test Results ◽  
Concrete Deterioration ◽  
Rebar Corrosion ◽  
Corrosive Environments

The concrete used in transmission lines are basically for foundations. The foundation concrete of transmission lines in corrosive environments has shown serious deterioration, which usually caused by concrete deterioration, rebar corrosion, degradation of bond strength between rebar and concrete due to various corrosive effects. Field tests are carried out in Wuhu area to research the durability of foundation concrete of transmission lines. And test results show that the concrete strength in the air is a litter higher than underground and the carbonization depth at the windward side is the largest of each foundation and the leeward side is the smallest, while those underground are close to zero.

scholarly journals Comparison of Mechanical Properties of Fiber-Reinforced Sand under Triaxial Compression and Direct Shear

2015 ◽  
Vol 7 (1) ◽  
Author(s):  
Reza Noorzad ◽  
Seyed Taher Ghoreyshi Zarinkolaei
Keyword(s):  
Shear Strength ◽  
Axial Strain ◽  
Triaxial Compression ◽  
Polypropylene Fiber ◽  
Triaxial Tests ◽  
Direct Shear ◽  
Test Results ◽  
Peak Reduction ◽  
Shear Tests ◽  
Direct Shear Tests

AbstractThis research investigates the behavior of sand reinforced with polypropylene fiber. To do this, 40 direct shear tests and 40 triaxial tests were performed on the coastal beaches of Babolsar, a city in the North of Iran. The effect of parameters such as fiber content, length of fiber and normal or confining pressure on the behavior of Babolsar sand have been studied. In this study, four various fiber contents (0, 0.25, 0.5 and 1 percent), three different lengths of fiber (6, 12 and 18 mm) and four normal or confining pressures (50, 100, 200 and 400 kPa) have been employed. The test results show that fiber inclusion has a significant effect on the behavior of sand. In both direct shear and triaxial tests, the addition of fibers improved shear strength parameters (C, '), increased peak shear strength and axial strain at failure, and also limited the amount of post-peak reduction in shear resistance. The comparison of the test results revealed that due to better fiber orientation toward the direction of principal tensile strain in triaxial test as compared to direct shear tests, the fiber efficiency and its effect on soil behavior is much more significant in triaxial specimens.

Red Sandstone Aggregate Mixture Experimental Study of Dynamic Compaction High Fill Embankment

2014 ◽  
Vol 1065-1069 ◽  
pp. 696-701
Author(s):  
Zhao Jun Chen ◽  
Wen Li ◽  
Xiang Qu
Keyword(s):  
Experimental Study ◽  
Rayleigh Wave ◽  
Dynamic Compaction ◽  
Direct Shear ◽  
Test Results ◽  
Shear Tests ◽  
Red Sandstone ◽  
Direct Shear Tests ◽  
Water Intensity ◽  
Intensity Decay

Direct shear tests by laboratory to study the red sandstone aggregate mixture under the action of water intensity decay law, got red sandstone aggregate mixture, fill high subgrade compaction experimental study, tests showed that dynamic compaction compacted earth and rock mix fill embankment feasible, Rayleigh Wave test results show that the effect of dynamic compaction compaction good.

scholarly journals Study on the Mechanical Properties of BFRP Tube Confined Concrete Short Columns under Axial Compression

2020 ◽  
Author(s):  
Xindong Ding ◽  
Shuqing Wang ◽  
Yu Liu ◽  
Zepeng Zheng
Keyword(s):  
Axial Compression ◽  
Brittle Failure ◽  
Failure Modes ◽  
Concrete Strength ◽  
Steel Tube ◽  
Confined Concrete ◽  
Test Results ◽  
Compression Tests ◽  
Short Columns ◽  
Square Steel Tube

Axial compression tests were carried out on 6 square steel tube confined concrete short columns and 6 BFRP square pipe confined concrete axial compression tests. The concrete strength grades were C30, C40, and C50. The test results show that the failure modes of steel pipe and BFRP pipe are obviously different, and the BFRP pipe undergoes brittle failure. Compared with the short columns of concrete confined by BFRP pipes, the ultimate bearing capacity of axial compression is increased by -76.46%, -76.01%, and -73.06%, and the ultimate displacements are -79.20%, -80.78%, -71.71%.

scholarly journals The Influence of Discrete Fibers on Mechanical Responses of Reinforced Sand in Direct Shear Tests

2021 ◽  
Vol 11 (19) ◽  
pp. 8845
Author(s):  
Chidochashe Clemency Nhema ◽  
Han Ke ◽  
Pengcheng Ma ◽  
Yunmin Chen ◽  
Shiyu Zhao
Keyword(s):  
Orientation Angle ◽  
Normal Pressure ◽  
Initial Orientation ◽  
Peak Strength ◽  
Specimen Preparation ◽  
Direct Shear ◽  
Initial Stiffness ◽  
Shear Tests ◽  
Reinforced Sand ◽  
Direct Shear Tests

To investigate the influences of discrete fiber strips on the mechanical properties of reinforced sand, a series of direct shear tests were conducted. A method to strictly control the initial orientation of fiber strips in specimen preparation was developed. Under the same normal pressure, the peak strength of sand specimens was proportional to the fiber content and was inversely proportional to the fiber initial orientation angle. The influences of initial fiber orientation on peak strength may depend on the stress mobilization in fibers. When the fiber strips distributed at a certain orientation angle were subjected to tensile stress in shearing, they could play an effective role in the peak strength gain of sand and vice versa. Due to the restriction of fibers on the volume dilation of sand specimens, the residual strength of reinforced sand also increased. However, the initial stiffness of reinforced sand was smaller than that of pure sand, which may be related to the precompression of flexible fiber strips and the density inhomogeneity of specimens induced in the specimen preparation process. In addition, the ductility of sand specimens was improved by the introduction of fiber strips, intuitively reflected by the increase in displacement failure. This may also be attributed to the restriction of fiber strips on the deformation of sand specimens.

scholarly journals Seismic Behavior Investigations of the Haunched Joint with Ribbed Anchor Webs in CFDST Structures

2021 ◽  
Author(s):  
yufen zhang ◽  
Hongfan Bu ◽  
Shengxi Cao
Keyword(s):  
Energy Dissipation ◽  
Stress Responses ◽  
Failure Modes ◽  
Concrete Strength ◽  
Material Strength ◽  
Fe Modeling ◽  
Test Results ◽  
Loading Test ◽  
Column Joint ◽  
Seismic Behaviors

Abstract The haunched joint with ribbed anchor webs in the concrete-filled double steel tubular (CFDST) structure was proposed in this study. The CFDST column and the steel beam were connected by vertical ribbed webs, which were anchored inside the column and connected to the beam web by the bolted connection, and haunches were welded to shift plastic hinges from the joint core to beam ends. The cyclic loading test was conducted on three beam-to-column joint specimens. Seismic behaviors including failure modes, strain and stress responses, hysteretic curves, ductility, and energy dissipation capacity were respectively analyzed. Besides, a finite element (FE) modeling was completed by ABAQUS in consideration of geometric and material nonlinearity. The validity of FE modeling was checked by comparisons between FE results and test results, and research results confirmed that the beam-to-column rotation and the shear deformation in the joint core were small owing to the restriction from the configuration of haunches. Then parametric investigations on connection constructional details, geometric dimensions, material strength, and axial compression ratios, were made to study seismic behaviors of the haunched joint with ribbed anchor webs. It showed that the selected parameters except concrete strength had certain influences on bearing capacity, ductility, and energy dissipation, and corresponding practicable design suggestions were proposed for the application of haunched joints with ribbed anchor webs in CFDST structures.

scholarly journals Experimental and Parametric Study on the Pull-Out Resistance of a Notched Perfobond Shear Connector

2019 ◽  
Vol 9 (4) ◽  
pp. 764 ◽  
Author(s):  
Shuangjie Zheng ◽  
Yuqing Liu ◽  
Yangqing Liu ◽  
Chen Zhao
Keyword(s):  
Failure Modes ◽  
Concrete Strength ◽  
Shear Connector ◽  
Test Results ◽  
Explicit Finite Element ◽  
Shear Connectors ◽  
Pull Out ◽  
Cutting Out ◽  
Circular Holes ◽  
Alternative Equation

To ease the installation of perforating rebars through multi-holes, an alternative notched perfobond shear connector was proposed by cutting out the hole edge. This paper presents the test results of six pull-out specimens with conventional and notched perfobond shear connectors. The objective was to compare the failure modes and pull-out behaviors of perfobond shear connectors using circular holes and notched holes. Furthermore, the explicit finite element method was introduced and validated to generate parametric results for pull-out tests of notched perfobond shear connectors. A total of 33 parametric simulations were performed to further study the influences of several variables, including the hole diameter, the cut width, the perfobond thickness, the concrete strength, the diameter and strength of the rebar, and the strength of the structural steel. The experimental and numerical results were used to evaluate the previous equations for perfobond shear connectors. Finally, an alternative equation was proposed to estimate the pull-out resistance of notched perfobond shear connectors.

Mechanical Properties of Fly Ash-Slag-Dredged Silt System Stimulated by Alkali

2013 ◽  
Vol 807-809 ◽  
pp. 1140-1146 ◽  
Author(s):  
Yi Xuan Chen ◽  
Xiu Li Sun ◽  
Zhi Hua Li
Keyword(s):  
Mechanical Properties ◽  
Shear Strength ◽  
Fly Ash ◽  
Construction Materials ◽  
Xrd Analysis ◽  
Test Results ◽  
X Ray Diffraction ◽  
Shear Tests ◽  
X Ray ◽  
Direct Shear Tests

The objective of this work is to investigate the stimulation effect of the addition of alkali on the fly ash and slag for stabilizing dredged silt. Based on the test results, a viable alternative for the final disposal of dredged silt as subgrade construction materials were proposed. For this purpose, several mixtures of dredged silt-fly ash-slag and alkali were prepared and stabilized/solidified. In this system, fly ash and slag were used as hardening agents (solidified materials) of dredged silt and alkali was used as activator of fly ash and slag. The shear strength of the mixture was tested by several direct shear tests. Furthermore, X-Ray Diffraction (XRD) analysis was used to determine the hydration products of the system. The specimens were tested in order to determine the shear strength changes versus hydration time and the alkali content. It is indicated that mechanical properties of solidified silt are improved significantly by addition of fly ash and slag stimulated by alkali.

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