scholarly journals Experimental Study of Bond Behavior Between Rebar and PVA-Engineered Cementitious Composite (ECC) Using Pull-Out Tests

2021 ◽  
Vol 8 ◽  
Author(s):  
Jie Xiao ◽  
Xiang Long ◽  
Ming Ye ◽  
Haibo Jiang ◽  
Lingfei Liu ◽  
...  
Keyword(s):  
Bond Strength ◽  
Layer Thickness ◽  
Volume Content ◽  
Cementitious Composite ◽  
Fiber Volume ◽  
Cover Layer ◽  
Bond Behavior ◽  
Engineered Cementitious Composite ◽  
Functional Relationships ◽  
Pull Out

As a novel civil engineering material, Engineered Cementitious Composite (ECC) has attracted more and more attention due to its strain-hardening characteristics, good post-cracking resistance and its unique properties. Bonding between Engineered Cementitious Composite (ECC) and rebar has a great effect on the mechanical behavior of structural members. In this paper, direct pull-out tests were conducted to understand the bond behavior between the ECC and rebar. The test parameters included rebar diameter and type, cover layer thickness, embedment length and fiber volume content. Bond-slip curves, failure and cracking pattern and bond strength were compared and discussed. The test results indicated that the bond strength decreased with the increase of embedded length. Through regression analysis with the test data, the functional relationships between bond strength and cover layer thickness and rebar diameter were fitted well. According to the positive and negative signs of the fitting parameters m and n, the relationship between the bond strength and the cover layer thickness and the rebar diameter could be determined. The bond strength increased obviously with the increase of fiber content. When the fiber volume content was 1, 1.5 and 2%, the bond strength of these specimens were 1.5, 2.5 and 3.1 times that of specimens without polyvinyl alcohol (PVA) fiber.

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%)).

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 Bond Behavior of Recycled Fiber Recycled Concrete with Reinforcement after Freeze-Thaw Cycles

Crystals ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 1506
Author(s):  
Yu Liu ◽  
Jinghai Zhou ◽  
Di Wu ◽  
Tianbei Kang ◽  
Aixia Liu
Keyword(s):  
Bond Strength ◽  
Recycled Concrete ◽  
Recycled Aggregates ◽  
Building Structures ◽  
Two Phase ◽  
Bond Behavior ◽  
Freeze Thaw ◽  
Pull Out ◽  
Recycled Fiber ◽  
Recycled Fibers

Freeze-thaw (F-T) damage is the major factor destroying the bond behavior of reinforced concrete in the cold areas of China. The bond behavior between recycled fiber recycled concrete (RFRC) and reinforcement after F-T cycles was investigated in this paper. The pull-out tests were undertaken with the replacement rate (0, 50%, and 100%) of recycled aggregates (RA) and volume content (0, 0.12%, and 0.24%) of recycled fibers (RFs) as test variables. The results demonstrate that the F-T cycles will reduce the bond strength between RFRC and reinforcement. Bond strength decreases by 69.41% after 150 cycles. Moreover, RF can improve the bond strength between RFRC and reinforcing steel. Bonding strength increases by 11.35% with the addition of 0.12% RF. A simplified two-phase bond-slip model between RFRC and reinforced steel after F-T cycles was eventually established, and it correlated well with the experimental results. This research presents a theoretical basis for the application of RFRC in building structures in cold areas.

Experimental Study on Effects of Fatigue Loading History on Bond Behavior between Steel Bars and Concrete

2016 ◽  
Vol 711 ◽  
pp. 673-680 ◽  
Author(s):  
Zhiwen Ye ◽  
Wei Ping Zhang ◽  
You Hu ◽  
Xiang Lin Gu
Keyword(s):  
Experimental Study ◽  
Bond Strength ◽  
Fatigue Loading ◽  
Critical Value ◽  
Concrete Cover ◽  
Repeated Loading ◽  
Loading History ◽  
Bond Behavior ◽  
Pull Out ◽  
Steel Bars

This paper presents an experimental investigation on the influence of fatigue loading history on bond behavior between steel bars and concrete. Reinforced concrete specimens were subjected to fatigue loadings with different amplitudes and cycles before undergoing eccentric pull-out tests. Tests revealed that all specimens failed with the splitting of the concrete cover. With increased loading cycles, the concrete in front of transverse ribs usually becomes denser at the beginning. Meanwhile, the initial bond stiffness and the bond strength increased, while the slip corresponding to the peak bond stress decreases. With the further increase of loading cycles, the bond strength begins to decrease after it reaches a critical value. This study determined that for specimens subjected to repeated loading with a larger amplitude, fewer cycles are needed for the bond strength to go up to the critical bond strength.

scholarly journals An Experimental Study on Effects of Corrosion and Stirrups Spacing on Bond Behavior of Reinforced Concrete

Metals ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 1327
Author(s):  
Konstantinos Koulouris ◽  
Charis Apostolopoulos
Keyword(s):  
Experimental Study ◽  
Reinforced Concrete ◽  
Bond Strength ◽  
Mass Loss ◽  
Corrosion Damage ◽  
Ongoing Research ◽  
Average Width ◽  
Concrete Cracking ◽  
Bond Behavior ◽  
Pull Out

The current experimental study consists of part of an extensive and ongoing research on bond behavior of RC elements damaged by corrosion, focusing on stirrups spacing effect on bonding. For this, RC specimens with different cases of stirrups spacing were casted. Accelerated corrosion was induced in order to simulate the slow process of nature corrosion on RC specimens and the corrosion damage was estimated in terms of mass loss of steel bars and average width of surface concrete cracking. Subsequently, pull-out tests were carried out to examine the bonding resistance between steel and concrete. The study indicates the great influence of density of stirrups on the percentage mass loss of the embedded reinforcing bar, accompanied by width of surface concrete cracking, as well as on bond strength between steel and concrete. The results of bond stress–slip curves show that the densification of stirrups plays a significant role in bonding, leading to higher bond strength values and delaying the degradation of bond loss as corrosion damage increases. However, it becomes apparent that, although the densification of stirrups (Φ8/60 mm) result in the full anchorage of steel-reinforcing bars, it may be inappropriate, since it can lead to a substantial increase in costs and a rapid rise in corrosion rate, due to potential increase. Furthermore, the recorded values of relative slip at bond strength are between 1 and 3 mm, regardless of corrosion damage or concrete cracking, which depends on the ribs geometry and crushing of concrete in front of them. To conclude, the results of the present manuscript indicate that the increase in transverse reinforcement (stirrups) percentage plays a key role in the durability of reinforced concrete elements and in bond strength maintenance between rebar and concrete.

Effect of Elevated Temperature on Bond Strength of Concrete

2019 ◽  
Vol 972 ◽  
pp. 26-33
Author(s):  
Muhammad Harunur Rashid ◽  
Md. Maruf Molla ◽  
Imam Muhammad Taki
Keyword(s):  
Mechanical Properties ◽  
Elevated Temperature ◽  
Bond Strength ◽  
Elevated Temperatures ◽  
Reinforced Concrete Structure ◽  
Bond Behavior ◽  
Pull Out ◽  
Steel Bar ◽  
Residual Capacity ◽  
Water Curing

In the case of exposure of reinforced concrete structure to accidental fire, an assessment of its residual capacity is needed. Bond strength of concrete was observed under elevated temperatures (150°, 250°, 350° and 500°C) in this study. Cylindrical specimens were prepared for pull-out tests to find out the bond behavior and to observe the mechanical properties of concrete. All the specimens were 100 mm diameter and 200 mm height. The pull-out specimens contain a 10 mm steel bar at its center. The specimens were tested at 52 days age following a 28 days water curing. Samples were preheated for 3 hours at 100°C temperature and then put into the furnace for 1 hour at the target temperature. Samples were tested before preheating as controlled specimens. In case of mechanical properties and the bond strength of concrete, there were no remarkable changes due to elevated temperature up to 150°C. However, the mechanical properties and bond strength were decreased gradually after 150°C temperature. Maximum reduction of bond strength observed was 52.13% and 49.8% at 500°C for testing within 1 hour and after 24 hours of heating respectively when compared to the controlled specimens. Bond strength was found to reduce at a greater rate than compressive strength due to the elevated temperature.

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