Bond behavior of high strength concrete under reversed pull-out cyclic loading

2002 ◽  
Vol 29 (2) ◽  
pp. 191-200 ◽  
Author(s):  
M Alavi-Fard ◽  
H Marzouk
Keyword(s):  
Cyclic Loading ◽  
Bond Strength ◽  
High Strength Concrete ◽  
Concrete Strength ◽  
High Strength ◽  
Displacement Curve ◽  
Bond Slip ◽  
Strength Concrete ◽  
Pull Out ◽  
Normal Strength

Structures located in seismic zones require significant ductility. It is necessary to examine the bond slip characteristics of high strength concrete under cyclic loading. The cyclic bond of high strength concrete is investigated under different parameters, including load history, confining reinforcement, bar diameter, concrete strength, and the rate of pull out. The bond strength, cracking, and deformation are highly dependent on the bond slip behavior between the rebar and the concrete under cyclic loading. The results of cyclic testing indicate that an increase in cyclic displacement will lead to more severe bond damage. The slope of the bond stress – displacement curve can describe the influence of the rate of loading on the bond strength in a cyclic test. Specimens with steel confinement sustained a greater number of cycles than the specimens without steel confinement. It has been found that the maximum bond strength increases with an increase in concrete strength. Cyclic loading does not affect the bond strength of high strength concrete as long as the cyclic slip is less than the maximum slip for monotonic loading. The behavior of high strength concrete under a cyclic load is slightly different from that of normal strength concrete.Key words: bond, high strength, cyclic loading, bar spacing, loading rate, failure mechanism.

scholarly journals Cyclical Behavior of Concrete-Encased Composite Frame Joints with High Strength Concrete

2015 ◽  
Vol 2015 ◽  
pp. 1-13 ◽  
Author(s):  
Lei Zeng ◽  
Zhenkun Cui ◽  
Yunfeng Xiao ◽  
Siqian Jin ◽  
Yuanyuan Wu
Keyword(s):  
Cyclic Loading ◽  
High Strength Concrete ◽  
Joint Strength ◽  
Concrete Strength ◽  
Outer Part ◽  
High Strength ◽  
Crack Pattern ◽  
Experimental Program ◽  
Strength Concrete ◽  
Composite Frame

This paper presents an application of high strength concrete to concrete-encased composite frame building based on an experimental program. The work emphasized joints behavior under reverse cyclic loading caused by earthquakes to provide information for seismic design. To investigate the internal mechanisms and seismic performance, cyclic loading tests were carried out on five half-scale interior joints. Two design variables were addressed in the research: concrete strength and axial column load. Frame joints performance including crack pattern, failure mode, deformation, ductility, strain distribution, and energy dissipation capacity was investigated. It was found that all joint specimens behaved in a manner with joint panel shear failure. Using high strength concrete increased the joint strength and had relatively little effect on the stiffness and ductility. The axial column load helped the joint strength by better mobilizing the outer part of the joint, but it had an obvious influence on the ductility and energy-dissipating capacity, which can be improved by providing enough transverse reinforcement. A typical crack pattern was also provided which can well reflect mechanical character and damage process. This research should contribute to the future engineering applications of high strength concrete to concrete-encased composite structure.

Bond Strength of Reinforcement in High-Strength Concrete

2000 ◽  
Vol 3 (3) ◽  
pp. 245-253 ◽  
Author(s):  
P. Mendis ◽  
C. French
Keyword(s):  
Bond Strength ◽  
High Strength Concrete ◽  
High Strength ◽  
Development Length ◽  
Normal Strength Concrete ◽  
Empirical Relationships ◽  
Strength Concrete ◽  
The World ◽  
Current Design ◽  
Normal Strength

The use of high-strength concrete is becoming popular around the world. The american code, ACI 318–95 is used in many countries to calculate the development length of deformed bars in tension. However, current design provisions of ACI 318–95 are based on empirical relationships developed from tests on normal strength concrete. The results of a series of tests on high-strength concrete, reported in the literature, from six research studies are used to review the existing recommendations in ACI 318–95 for design of splices and anchorage of reinforcement. It is shown that ACI 318–95 equations may be unconservative for some cases beyond 62 MPa (9 ksi).

Seismic behavior of normal-strength concrete-filled precast high-strength concrete centrifugal tube columns

2019 ◽  
Vol 23 (4) ◽  
pp. 614-629
Author(s):  
Shaohua Zhang ◽  
Xizhi Zhang ◽  
Shengbo Xu ◽  
Xingqian Li
Keyword(s):  
Axial Compression ◽  
High Strength Concrete ◽  
Seismic Behavior ◽  
Failure Modes ◽  
Concrete Strength ◽  
High Strength ◽  
Test Results ◽  
Normal Strength Concrete ◽  
Strength Concrete ◽  
Normal Strength

This study reports the cyclic loading test results of normal-strength concrete-filled precast high-strength concrete centrifugal tube columns. Seven half-scale column specimens were tested under cyclic loads and axial compression loads to investigate their seismic behavior. The major parameters considered in the test included axial compression ratio, filled concrete strength, and volumetric stirrup ratio. The structural behavior of each specimen was investigated in terms of failure modes, hysteresis behavior, bearing capacity, dissipated energy, ductility, stiffness degradation, drift capacity, and strain profiles. Test results revealed that the concrete-filled precast high-strength concrete centrifugal tube column exhibited good integral behavior, and the failure modes of all columns were ductile flexural failures. Lower axial compression ratio and higher volumetric stirrup ratio resulted in more satisfactory ductile performance. In contrast, the filled concrete strength has a limited influence on the structural behavior of concrete-filled precast high-strength concrete centrifugal tube columns. Based on the limit analysis method, the calculation formula for the bending capacity of the concrete-filled precast high-strength concrete centrifugal tube column was developed, and the results predicted from the formulas were in good agreement with the experiment results.

BOND STRENGTH RECOVERY OF FIRE-DAMAGED CONCRETE AFTER POST-FIRE-CURING

2015 ◽  
Vol 2 (1) ◽  
Author(s):  
Zhuguo Li ◽  
Yasuhiro Ryuda
Keyword(s):  
Bond Strength ◽  
High Strength ◽  
Test Results ◽  
Strength Concrete ◽  
Pull Out ◽  
Strength Recovery ◽  
Steel Bars ◽  
Bond Strengths ◽  
Normal Strength ◽  
Curing Age

The effects of post-fire-curing on the bond strength recovery of fire-damaged concrete were investigated in this study. Normal strength concrete (NSC) and high-strength concrete (HSC) specimens with deformed steel bars were prepared respectively. We measured the bond strength of unheated NSC and HSC, and exposed other NSC and HSC specimens to high temperatures of 300℃, 400℃, and 500℃, respectively for 120 minutes. Following by rapid cooling with water, the bond strengths of heated NSC and HSC were measured instantly without re-curing, the remains were cured in water for 28 days, or further in the air of 20℃, 60% R.H. for 56 ~62 days. After the re-curing, the pull-out tests were conducted. The test results indicate that the post-fire-curing contributes to a substantial bond strength recovery of heated concrete. The longer the re-curing in water, the greater the recovery extent. At 90 days of re-curing age, the bond strength rose up to around 77% for NSC, and around 70% for HSC, respectively.

Evaluation of Bond Strength between Steel Fiber Reinforced Ultra-High Strength Concrete and Rebar

2015 ◽  
Vol 665 ◽  
pp. 41-44
Author(s):  
B.I. Bae ◽  
Hyun Ki Choi ◽  
Chang Sik Choi
Keyword(s):  
Bond Strength ◽  
High Strength Concrete ◽  
Steel Fiber ◽  
High Strength ◽  
Fiber Reinforced ◽  
Strength Concrete ◽  
Pull Out ◽  
Reinforced Concrete Member ◽  
Significant Difference ◽  
Cover Thickness

In order to design reinforced concrete member using steel fiber ultra high strength concrete, current structural design methods should be re-evaluated because it has significant difference in material characteristics compared with normal concrete. In this study, bond strength of steel fiber reinforced ultra-high strength concrete was evaluated. For this purpose, direct pull out test specimens were constructed with variables of cover thickness, compressive strength of matrix and fiber inclusion ratio. According to the test, bond strength were sensitively varied with cover thickness and fiber inclusion. Because bond strength was determined by tensile strength of concrete. Comparing test results with theoretical methods suggested by Tepfers, specimens without steel fiber show good agreement with analytical method, because this method were based on elasticity. And other empirical equations were evaluated with other previous researches.

scholarly journals Effect of different grades of concrete on rc framed multi-storied building

2021 ◽  
Vol 309 ◽  
pp. 01194
Author(s):  
Vemundla Ramesh ◽  
Chitla Raju
Keyword(s):  
High Strength Concrete ◽  
Ground Motions ◽  
Concrete Strength ◽  
Tall Buildings ◽  
Drying Shrinkage ◽  
High Strength ◽  
Normal Strength Concrete ◽  
Material Technology ◽  
Strength Concrete ◽  
Normal Strength

Due to the application of advanced material technology, concrete with high compressive strength is currently produced and used in many countries. This type of concrete can be produced by micro-silica and superplasticizers as well as applying good quality control procedures. The use of high-strength concrete (HSC) in building construction is becoming popular because it has many advantages such as increased strength and stiffness, reduced size of concrete sections, improved resistance to creep and drying shrinkage, and material durability. Therefore we can use high strength concrete (HSC) in columns and normal strength concrete (NSC) for beams & floor sections. Thus this study will investigate the performance of 8 storey tall buildings in ZoneIV for medium grade soil with varying high strength concrete (HSC) normal strength concrete (NSC) subjected to far-field ground motions scaled to collapse of the structure using varying grades (M20, M25, M30, M35, M40, and M50) of concrete strength subjected to seismic ground motions scaled to collapse of the structure using a linear static method and this will be achieved through analytical modeling and analysis using ETABS2018 software.

scholarly journals Effect of Internal Curing with Superabsorbent Polymers on Bond Behavior of High-Strength Concrete

2020 ◽  
Vol 2020 ◽  
pp. 1-13
Author(s):  
Xiao Lei ◽  
Rui Wang ◽  
Hanwan Jiang ◽  
Faxiang Xie ◽  
Yanni Bao
Keyword(s):  
Bond Strength ◽  
High Strength Concrete ◽  
High Performance ◽  
High Performance Concrete ◽  
High Strength ◽  
Internal Curing ◽  
Superabsorbent Polymers ◽  
Strength Concrete ◽  
Bond Performance ◽  
Pull Out

High-strength concrete (HSC) is widely used in engineering due to its high strength and durability. However, because of its low water-to-cement ratio, external curing water hardly enters the dense internal structure of HSC so that high self-desiccation shrinkage often takes place. As a result, superabsorbent polymers (SAP) are added as an internal curing material to effectively reduce the shrinkage of high-performance concrete. Meanwhile, the bond performance between reinforcing steel and SAP HSC concrete remains unknown. In this paper, the bond performance of HSC mixed with SAP is studied by pull-out tests, and the results were obtained as follows: (1) the bond strength of HSC mixed with SAP increased first and then decreased with the increase of SAP content; (2) the slip at ultimate bond strength of HSC with SAP decreased with the increase of compressive strength; (3) a prediction model of the stress-slip relationship between steel rebars and HSC was established.

Experimental investigation of the flexural ductility of singly reinforced concrete beam using normal and high strength concrete

2019 ◽  
Vol 1 (2) ◽  
pp. 218-224
Author(s):  
Atur P.N. Siregar
Keyword(s):  
Experimental Investigation ◽  
High Strength Concrete ◽  
Concrete Beams ◽  
Concrete Strength ◽  
High Strength ◽  
Reinforced Concrete Beam ◽  
Normal Strength Concrete ◽  
Strength Concrete ◽  
Flexural Ductility ◽  
Normal Strength

This paper discusses and reports based on the experimental investigation of the flexural ductility of singly reinforced normal strength and high strength concrete beams. Compressive concrete strength of 40 and 95 MPa were employed to create singly reinforced normal strength and high strength concrete beams, respectively. Fourteen samples made of normal and high strength concrete were engaged to observe the flexural ductility behaviour of beams on the basis of four point bend testing. Analysis on the basis of the flexural cracking, ultimate failure and curvature ductility were carried out to derive the comparison of singly reinforced normal strength and high strength beams. The beams using high strength concrete revealed a higher ductility ratio than that of normal strength concrete, i.e. 4.50 for high strength concrete and 2.60 for normal strength concrete.

Bond Strength Of Deformed Bars and Steel Fibers in High Strength Concrete

1987 ◽  
Vol 114 ◽  
Author(s):  
Methi Wecluat ◽  
Schboon Chimamphant
Keyword(s):  
Compressive Strength ◽  
Bond Strength ◽  
High Strength Concrete ◽  
High Strength ◽  
Fiber Reinforced Concrete ◽  
Steel Fibers ◽  
Fiber Reinforced ◽  
Strength Concrete ◽  
Pull Out ◽  
Deformed Bar

ABSTRACTIn recent years, the means of making high strength concrete are simple by adding microsilica, fly ash, or other types of additives. As the use of high strength concrete increases, the need to clearly understand its prcperties is essentially a necessity for engineering design. While much of the basic properties of high strength concrete such as compressive strength (fc), modulus of elasticity (Ec), and modulus of rupture (fr), etc., has been investigated and reported recently, many remain unavailable. This paper presents the bond strength characteristics of deformed bar, steel fibers, and normal aggregate in high strength concrete matrix. The compressive strength of concrete used in this study is 75–80 MPa (11,000-12,000 psi). Bond slip relationships of deformed bars of three different bar diameters were obtained from the pull-cut test. Two types of steel fiber reinforced high strength cemented composites were tested in a directtension, tapered specimen to observe the pulled-out behavior of steel fibers. Fiber reinforced concretes with fiber volume fraction of 0.5, 1.0, 1.5, and 2.0 % were compared to the unreinforced matrix. A direct-tension, dog boned specimen was used to study the bond between aggregate-matrix interface. The results from this study indicate that high strength concrete is generally more brittle, and in essence, allows less microcracking, less slippage, and less pulled-out deformation. This general trend is observed in both the deformed bar and fiber pulled-out as well as in aggregate-matrix interfacial debonding. The maximum slip of deformed bars in high strength concrete is about 0.15 mm.(0.006 in.) which is only one-tenth of that reported for normal concrete as 1.5 to 2.0 mm.(0.06–0.08 in.). A normalized pull-out stress-displacement relationship of high strength fiber reinforced concrete exhibits a unique behavior similar to those reported for normal fiber reinforced matrix.

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