Experimental Research on Bond Strength between Rebar and Concrete after High Temperature

2011 ◽  
Vol 71-78 ◽  
pp. 1057-1061 ◽  
Author(s):  
Ke Fang Yin ◽  
Yang Han ◽  
Yi Liu
Keyword(s):  
Reinforced Concrete ◽  
High Temperature ◽  
Bond Strength ◽  
Experimental Research ◽  
Bonding Strength ◽  
Different Temperatures ◽  
Ultimate Bond Strength

With the centrally pulling-out test, the bond strength of reinforced concrete is measured with different temperatures and different cooling ways after high temperature; and the ultimate bond strength and slip of reinforced and concrete under different conditions are analyzed. The results show that the bonding strength declines gradually with the increase of temperature, and the ultimate slippage also decreases gradually.

Experimental Research on Reinforcing Effect of Spiral Steel Fiber

2012 ◽  
Vol 174-177 ◽  
pp. 668-671
Author(s):  
He Ting Zhou
Keyword(s):  
Reinforced Concrete ◽  
Bond Strength ◽  
Experimental Research ◽  
Significant Role ◽  
Steel Fiber ◽  
Cement Mortar ◽  
Fiber Reinforced Concrete ◽  
Steel Fibers ◽  
Steel Fiber Reinforced Concrete ◽  
Reinforcing Effect

Steel fiber has a fine nature in reinforcing concrete. This essay aims to find out the influence of physical forms of steel fiber on its nature of reinforcement. By comparing two types of cement mortar reinforced by steel fibers, it is found that spiral steel fibers have a better bond strength with matrix than straight ones. Therefore, a conclusion could be drawn that physical forms of the steel fiber play a significant role in steel fiber reinforced concrete, and the experiment also serves a rewarding reference to the application of spiral steel fibers.

Evaluation and modeling of ultimate bond strength of corroded reinforcement in reinforced concrete elements

2015 ◽  
Vol 49 (8) ◽  
pp. 3195-3215 ◽  
Author(s):  
Esra Mete Güneyisi ◽  
Kasım Mermerdaş ◽  
Ayşegül Gültekin
Keyword(s):  
Reinforced Concrete ◽  
Bond Strength ◽  
Concrete Elements ◽  
Ultimate Bond Strength

Bond Strength between Steel and Concrete Experiment Analysis at Different Temperatures

2014 ◽  
Vol 1065-1069 ◽  
pp. 1977-1980
Author(s):  
Tao Zou ◽  
Yu Lai Han
Keyword(s):  
Reinforced Concrete ◽  
Bond Strength ◽  
Theoretical Consideration ◽  
Relative Slip ◽  
Axial Tension ◽  
Data Segment ◽  
Depth Study ◽  
Different Temperatures ◽  
Bonding Properties ◽  
Experiment Analysis

It is known in the literature, at different temperatures bond strength bond between steel and concrete and relevant test data segment free end slip magnitude rarely, it is necessary to study this type of test, in order to more in-depth study of steel and variation between concrete bonding properties at different temperatures in order to verify different temperatures we derive between steel and concrete expressions are appropriate bond stress and slip. This test is primarily measured under different temperature conditions, reinforced concrete specimens under axial tension force central role, respectively, at the free end of the specimen and loading end bond segment relative slip steel and concrete at different temperatures . Because when the temperature reaches about 200 °C, the specimen began to appear on the adhesive debonding phenomenon, so this calculation is only done by experiments and theoretical consideration a temperature in the range of 20 °C to 190 °C.

scholarly journals Influence of concrete admixture on the bond strength of reinforced concrete submitted to high temperature

2020 ◽  
Vol 13 (2) ◽  
pp. 212-221
Author(s):  
V. A. JERÔNIMO ◽  
A. C. PICCININI ◽  
B. V. SILVA ◽  
D. S. S. GODINHO ◽  
A. M. BERNARDIN ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Reinforced Concrete ◽  
High Temperature ◽  
Bond Strength ◽  
Modulus Of Elasticity ◽  
Significant Loss ◽  
Group I ◽  
Influence Of Temperature On ◽  
Strength Curve ◽  
Temperature Exposure

Abstract High temperatures can affect the macro and micro structural properties of reinforced concrete. This work aimed to analyze the bond strength behavior after high temperature exposure of two classes of concrete, the conventional 30 MPa and the high compressive strength 65 MPa concrete. The pullout test proposed by RILEM CEB / FIP RC6 (1983) was used for the evaluation of the compressive strength and modulus of elasticity. The influence of temperature on the physical-mechanical properties of concrete samples under a simulated fire situation was also studied for the evaluation of the resistant capacity in a post-fire situation. In addition to the analysis at 28 days, samples of the 30 MPa (group I) and 65 MPa (group II) classes were also investigated at 90 days exposed to room (23 °C), 400 °C and 800 °C temperatures. The bond strength curve was similar to that of compressive strength, where, at 400 °C, there was no statistical difference regarding room temperature and, at 800 °C, there was significant loss of strength in all cases. At 90 days age there was a loss of bond strength of 51 and 40 % for groups I and II, respectively. At 800°C the reductions were above 50 % in compressive strength and above 80 % in the modulus of elasticity, for both groups. These results show the structural impairment under high temperature. Comparing the test 28 and 90 days ages, there was no significant influence of age on the bond and compressive strength of the concretes.

Research on Bonding Strength of Steel and Concrete with Different Bonding Interfaces

2013 ◽  
Vol 470 ◽  
pp. 838-841 ◽  
Author(s):  
Zong Ping Chen ◽  
Ying Liang ◽  
Yu Liang Chen
Keyword(s):  
Bond Strength ◽  
Cross Sections ◽  
Bonding Strength ◽  
Failure Process ◽  
Loading Test ◽  
Test Load ◽  
Concrete Failure ◽  
Push Out ◽  
Ultimate Bond Strength

For the purpose of researching the natural bonding behavior of different interfaces between steel and concrete in SRC structures, four specimens are designed to launch the monotonic push-out loading test. Each specimen is used to consider one case, including the bonding of the external flange, internal flange, web and whole cross-sections with the concrete. Failure process and modes of these specimens were observed during the test. Load-slip curves and ultimate bond strength are obtained and the bonding strength between different interfaces of steel and concrete was analyzed. The results show that the bonding strengths of different interfaces in SRC members are not equal. The minimum bonding strength occurs in web, the bonding strength of external flange is higher, and the maximum bonding strength occurs in internal flange, the ratio of the strength is 1:1.39:1.59.

Effect of B4C and SiO2 on Bond Property for Phenolic Resin-Based Adhesive

2018 ◽  
Vol 281 ◽  
pp. 959-963
Author(s):  
Feng Zhang ◽  
Chuan Qi Hu ◽  
Shi Chao Zhang ◽  
Hao Ran Sun ◽  
Yuan Tian ◽  
...  
Keyword(s):  
Heat Treatment ◽  
High Temperature ◽  
Bond Strength ◽  
Boron Carbide ◽  
Bonding Strength ◽  
Heat Treatment Temperature ◽  
Room Temperature ◽  
Phenolic Resin ◽  
Optical Microscope ◽  
Treatment Temperature

In this paper, the modified phenolic resin-based adhesive was prepared by dissolving different components. After low temperature curing, SiC samples were bonded by the binder. The samples were treated at different temperatures (400°C, 800°C, 1200°C, 1500°C) under an inert atmosphere. The bonding strength of samples was tested after heat treatment at room temperature. The results showed that the bonding strength of the B4C modified phenolic resin (PF) based adhesive is the highest. When the heat treatment temperature was above 1200°C, the bond strength increased with the additive amount of boron carbide at room temperature. The microstructures of the samples were observed by optical microscope and scanning electron microscope. The effects of the modified filler and heat treatment temperature on the bonding strength of the phenolic resin based adhesive were investigated. The bonding strength of boron carbide-modified phenolic resin-based binder was tested under high temperature. It was found that the bond strength at high temperature was lower than that at room temperature, and the bond strength decreased with the increase of temperature.

scholarly journals A Study on the Bond Behavior of Corroded Reinforced Concrete Containing Recycled Aggregates

2015 ◽  
Vol 2015 ◽  
pp. 1-9 ◽  
Author(s):  
Haifeng Yang ◽  
Zhiheng Deng ◽  
Yinghong Qin ◽  
Liangsheng Lv
Keyword(s):  
Reinforced Concrete ◽  
Bond Strength ◽  
High Strength ◽  
Recycled Concrete ◽  
Recycled Aggregate Concrete ◽  
Recycled Aggregate ◽  
Recycled Aggregates ◽  
Bond Slip ◽  
Rebar Corrosion ◽  
Ultimate Bond Strength

This paper investigated bond-slip characteristics of chloride-induced corroded reinforced concrete incorporating different levels of recycled concrete aggregates (RCA). Pullout tests were adopted to evaluate the bonding and debonding behaviors of the embedded rebar experiencing different corrosion levels. Both high- and low-strength concrete were considered. Bond-slip curves were recorded to determine the influences of rebar corrosion levels and RCA replacements on the bond strength and debonding energy of the specimens. Test results indicate that increasing rebar corrosion level gradually weakens the antisliding ability of reinforced recycled aggregate concrete (RAC) except for a small level corrosion and the degradation rate of ultimate bond strength increases with a decrease of compressive strength at 0.5% rebar corrosion. The results also demonstrate that the ultimate bond strength of reinforced RAC slightly decreases with an increase of RCA replacement. However, the relative bond strength between uncorroded rebar and RAC is little affected by RCA content, while it decreases with an increase of RCA replacement in high-strength specimens after rebar corrosion. The debonding energy between deformed rebar and RAC is found decreasing with the increment of the rebar corrosion level and increasing with an increase of RAC content.

Role of synthetic fibers in delaying steel corrosion cracks and improving bond with concrete

2001 ◽  
Vol 28 (5) ◽  
pp. 787-793 ◽  
Author(s):  
Rami H Haddad ◽  
Ahmed M Ashteyate
Keyword(s):  
Reinforced Concrete ◽  
Bond Strength ◽  
Steel Corrosion ◽  
Concrete Cover ◽  
Fiber Reinforced Concrete ◽  
Synthetic Fiber ◽  
Special Treatment ◽  
Fiber Reinforced ◽  
Bar Diameter ◽  
Ultimate Bond Strength

An experimental study was conducted to investigate the bond behavior between corroding reinforcing steel and surrounding synthetic fiber reinforced concrete. Pullout concrete and fiber reinforced concrete specimens were prepared at concrete cover to steel bar diameter ratios of 3.1 and 3.7 with three embedded lengths of 100, 200, and 300 mm. Fiber reinforced concrete was prepared using polypropylene at 0.15% and 0.30% or nylon fibers at 0.3% by mix volume. After moist curing for 90 days, pullout specimens, originally contaminated by up to 11 kg/m3 NaCl, were subjected to a special treatment to accelerate corrosion in steel. The bond stress–slippage relationship was evaluated at different corrosion levels. The findings indicated that the use of fibers delayed initiation of cracking, due to steel corrosion, and improved the ultimate bond strength at cracking and post-cracking stages. The percentage improvement in ultimate bond strength at the latter stages reached as high as 52% and 87%, respectively. It was noticed that, prior to cracking, corrosion of steel bars resulted in an increase in bond strength, regardless of the concrete cover to bar diameter ratio used, or whether fibers were used or not. After cracking (due to steel corrosion), pullout specimens prepared with polypropylene fibers showed better resistance than that of corresponding ones with nylon fibers.Key words: fibers, reinforced concrete, corrosion, cracking, bond strength, slippage.

scholarly journals Bond Behavior of Steel-Recycled Aggregate Concrete Interface After High Temperatures and Spraying Water Cooling

2021 ◽  
Vol 8 ◽  
Author(s):  
Chunheng Zhou ◽  
Jiazhang Cao ◽  
Zongping Chen
Keyword(s):  
High Temperature ◽  
Bond Strength ◽  
High Temperatures ◽  
Recycled Aggregate Concrete ◽  
Recycled Aggregate ◽  
Water Cooling ◽  
Bond Properties ◽  
Aggregate Concrete ◽  
Concrete Interface ◽  
Ultimate Bond Strength

Using recycled aggregate concrete (RAC) in steel-reinforced concrete structure is an effective way to eliminate the adverse effects of recycled aggregate, which has an excellent application prospect. Fire has a great destructiveness to steel-reinforced recycled aggregate concrete (SRRAC) structure; hence, the bond performance of SRRAC after high temperature, as the prerequisite for the composite between steel and RAC, is the key problem for structural safety and the corresponding safety assessment after fire. In this article, the residual bond behaviors of steel-recycled aggregate concrete interface after different high temperatures and spraying water cooling were studied through the push-out test. The failure modes and load–slip curves were examined. The ultimate bond strength, residual bond strength, and elastic bond shear stiffness of specimens after high temperature and cooling for the regime of spraying water were evaluated and compared to that of natural air. A parametric analysis of temperature, replacement percentage, and studs was conducted. A calculation approach for the ultimate bond strength and residual bond strength of SRRAC after high temperature was developed based on the sensitive analysis of gray system theory and regression analysis. Results showed that the bond properties of SRRAC specimens after high temperature were decreased as exposure temperature increased. The cooling regime of spraying water has a more significant influence on the ultimate strength and residual strength than that of natural air. The specimens with studs on both flange and web have the highest bond properties after high temperature. In all the factors, the number of studs showed the largest gray relational degree to the bond strength of SRRAC. The developed approach provided a reliable prediction of bond strength for SRRAC after high temperature.

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