Study on the Effect of Bond-Anchoring Factor on Bond Behavior between Deformed Bar and Shale Ceramic Concrete

2011 ◽  
Vol 403-408 ◽  
pp. 444-448
Author(s):  
Wei Jun Yang ◽  
Jie Yu ◽  
Yan Wang

In this paper, the effect of bond-anchoring factor on bond behavior between deformed bar and shale ceramic concrete was analyzed by four groups of pull-out tests with different anchorage length. And three reinforced concrete pull-out tests used for comparative analysis were prepared at the same time. We obtained a series of experimental data and based on these data .A more accurate formula was summed up. This formula has a high value in guiding the practical project to choose the anchorage length.

2011 ◽  
Vol 366 ◽  
pp. 281-285 ◽  
Author(s):  
Jian Yu Yang ◽  
Jie Yu ◽  
Yan Wang

In this paper, the effect of cover thickness on bond behavior between deformed bar and shale ceramsite concrete was analyzed by four groups of pull-out tests which with different cover thickness. And three reinforced concrete pull-out tests used for comparative analysis were prepared at the same time. We obtained a series of experimental data and based on these data a more accurate formula was summed up. This formula has a high value in guiding the practical project to choose the cover thickness.


2012 ◽  
Vol 502 ◽  
pp. 458-462
Author(s):  
Yan Wu ◽  
Jie Yu ◽  
Yan Wang

In this paper, the effect of age on bond behavior between deformed bar and shale ceramic concrete was analyzed by four groups of pull-out tests with different age. And three reinforced concrete pull-out tests used for comparative analysis were prepared at the same time. We obtained a series of experimental data and based on these data a more accurate formula was summed up. This conclusion is important for further study on bonding properties of ceramic concrete and has a high value in guiding the actual construction.


2013 ◽  
Vol 639-640 ◽  
pp. 334-340
Author(s):  
Wen Ling Tian ◽  
Li Min Zhang

Textile reinforced concrete (TRC) allows the light weight structures and offers a high effectiveness of the reinforcement by using continuous yarns. The study on the bond behavior between textile and concrete matrix is significant for the development of computational methods that analyze the textile reinforced concrete. The paper analyzes the bonding constitutive model of TRC and the bonding mechanism that the stress is transferred from fine concrete to textile, pointing out quadruple linear model can accurately reflect the bond behavior between fiber and concrete, illustrates the main influences on bond between the fine grained matrix and fabrics based on the pull-out test, the result reveals that with initial bond length increasing, the maximum pull force increases, and increasing concrete strength and improving workability of concrete matrix, epoxy resin impregnating and sand covering of textile as well as prestressing textile can increase the bond strength between textile and concrete. Finally the paper proposes that epoxy resin impregnating and 0.15 ~ 0.30mm sand covering of textile can be used as a practical method of improving bond properties in the engineering.


2016 ◽  
Vol 20 (9) ◽  
pp. 1390-1405 ◽  
Author(s):  
Ahmed A Abouhussien ◽  
Assem AA Hassan

This article presents the results of an experimental investigation on the application of acoustic emission technique for monitoring the steel-to-concrete bond integrity of reinforced concrete structures. A series of direct pull-out tests were performed on 54 reinforced concrete unconfined prism samples with variable rebar diameter (10, 20, and 35 mm), embedded length (50, 100, and 200 mm), and concrete cover (20, 30, and 40 mm). The samples were tested under incrementally increasing monotonic loading while being continuously monitored via attached acoustic emission sensors. These sensors were utilized to acquire different acoustic emission signal parameters emitted throughout the tests until failure. Also, an acoustic emission intensity analysis was implemented on acoustic emission signal strength data to quantify the damage resulting from loss of bond in all tested specimens. This analysis employed the signal strength of all recorded acoustic emission hits to develop two additional parameters: historic index ( H ( t)) and severity ( Sr). The results of bond behavior, mode of failure, and free end slip were compared with the recorded acoustic emission data. The results showed that the cumulative number of hits, cumulative signal strength, H ( t), and Sr had a good correlation with different stages of bond damage from de-bonding/micro-cracking until bond splitting failure and bar slippage, which caused cover cracking or delamination. The analysis of cumulative signal strength and H ( t) curves enabled early identification of two progressive stages of bond degradation (micro-cracking and macro-cracking) and recognized the various modes of failure of the tested specimens. The variations of bar diameter, concrete cover, and embedded length yielded significant impacts on both the bond behavior and acoustic emission activities. The results also presented developed intensity classification charts, based on H ( t) and Sr, to assess the bond integrity and to quantify the bond deterioration (micro-cracking, macro-cracking, and rebar slip) in reinforced concrete structures.


Author(s):  
Mohammed A. Abed ◽  
Zaher Alkurdi ◽  
Ahmad Kheshfeh ◽  
Tamás Kovács ◽  
Salem Nehme

The bond-slip relationship between concrete and steel is significant in evaluating the nonlinear behavior of reinforced concrete structures. The force transmitted by the bond in reinforced concrete structures was studied numerically in high-strength, lightweight concrete with ribbed reinforcing steel bar or seven-wire strand, using ATENA 3D software. The first part of the study was a validation of the model based on the actual results of standardized pull-out tests using the software. Subsequently, the bond behavior was studied, where a four-point static bending test was modeled based on the real bond-slip relationship of the pull-out test. It was deduced that the ATENA 3D software can simulate the experimental tests and provide meaningful results. In addition, inferred from the numerical modeling, the maximum crack width and the mid-span deflection of the reinforced concrete beam increased when the bond stress between the concrete and the reinforcing steel bars was decreased. When a high amount of reinforcement (two strands) was used, concrete failure occurred before the strands yielded. However, further increase of the bond stress also decreased the maximum crack width and mid-span deflection. The failure occurred due to the increase in the strand yielding point by using one strand as a reinforcement of the beam.


Author(s):  
Klaus Holschemacher ◽  
Ahsan Ali ◽  
Shahid Iqbal

In construction industry lightweight concrete and fiber reinforced concrete are being used for many years. The former is known for brittle nature, light in weight and low thermal conductivity properties. It also offers better workability when compared to the normal weight concrete for the same slump value. These properties are however affected by addition of discrete fibers. Among the affected properties is also the bond between steel and concrete surrounding it. The integrity of a reinforced concrete member is not ensured in the absence of adequate bond. Due to limited literature on the subject matter, an experimental program was carried out to understand the bond behavior in lightweight concrete after fiber inclusion. For the purpose modified pull-out specimens made of Lightweight Fiber Reinforced Concrete (LWFC) were tested. Hooked end steel fibers having length 35 mm and diameter 0.5 mm (l/d = 0.7) were incorporated in dosages of 0, 20, and 40 kg/m3. Besides pull-out specimens, testes were also carried out for fresh and hardened properties of LWFC. Tests results indicate higher pull-out loads for higher fiber contents. The average increase in ultimate bond strength was observed at 28% and 2% for 40 kg/m3 and 20 kg/m3 fiber contents respectively. The fresh concrete density, compressive strength of mixes reduced and air-content values increased with increase in fiber content.


2020 ◽  
Vol 2020 ◽  
pp. 1-18
Author(s):  
Xiaoyu Bai ◽  
Xueying Liu ◽  
Mingyi Zhang ◽  
Yonghong Wang ◽  
Zheng Kuang ◽  
...  

Glass fiber reinforced polymer (GFRP) antifloating anchors are widely used in reinforcing underground structures. Despite the outstanding application advances of GFRP anchors in the antifloating field, research on the mechanical transmission and deformation properties of the anchor rod and anchorage body is still scarce. This paper introduces pull-out experiments of GFRP antifloating anchors based on the FBG sensor strings technology. The experimental data demonstrates that the distribution curve of the axial stress shows a reversed-S shape, and the shear stress distribution presents the law of increasing first and then decreasing from the position of peak shear stress. The rod-anchorage body displacement difference curves of the anchors with an anchorage length that is closer to the critical anchorage length are smoother than those of the anchors with a larger length difference from the critical anchorage length. Finally, a simplified distribution model of the shear stress is applied for predicting the rod-anchorage body displacement difference, and the experimental data of the anchors with a rod slip failure is more applicable for this model than that of the anchors with a rod rupture failure.


2014 ◽  
Vol 617 ◽  
pp. 225-228 ◽  
Author(s):  
David Čítek ◽  
Petr Huňka ◽  
Stanislav Řeháček ◽  
Jiří Kolísko

Ultra High Performance Concrete - UHPC has become increasingly used. Its outstanding features are generally known. It is a fact that the bond of the reinfocement in UHPC is better than that in ordinary concrete, but this bond needs to be quantified .The aim of the experimental research was to determine the average bond stress between prestressing strands and different types of UHPC and to show very significant increase in the average shear stress in bond with UHPC compared to ordinary concrete. In order to determine the bond capacity, an experimental research was carried out. Experimental details of the models in real structures – parts of prestressed girders made from UHPC, were tested in the laboratory and the results were compared with specimens prepared according to standard. The influence of different material properties and different anchorage length of prestressing strands to bond behavior of UHPC was examined in pull out tests. Test results of bond test led to the conclusion that the application of UHPC can significantly reduce the anchorage length of reinforcement compared with the ordinary concrete.


Metals ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 1327
Author(s):  
Konstantinos Koulouris ◽  
Charis Apostolopoulos

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.


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