scholarly journals STUDY ON BONDING PROPERTY OF POLYURETHANE CEMENT (PUC) TO STEEL BAR

2021 ◽  
Vol 30 (3) ◽  
Author(s):  
Kexin Zhang
Keyword(s):  
Bond Strength ◽  
Protective Layer ◽  
Stress Process ◽  
Anchorage Length ◽  
Bond Slip ◽  
Pull Out ◽  
Steel Bar ◽  
Bonding Property ◽  
Bonding Properties ◽  
Reinforcement Bar

The pull-out test of the bar and PUC is carried out in this paper, the effects of protective layer thickness, reinforcement anchorage length, diameter and shape of reinforcement on bonding properties were studied. The results show that the bond strength between reinforcement and PUC material increases with the increase of the thickness of the protective layer, but decreases with the increase of the anchorage length and diameter of reinforcement. The bond strength of bare round steel is significantly lower than that of ribbed steel, and the maximum bond strength is about 47.4% of ribbed steel. By analyzing the bond slip curve obtained from the pull-out test, the stress process of bond anchorage between reinforcement bar and PUC material is mainly summarized into three stages: the rising stage, the falling stage and the residual stage. The characteristics of the curve, the stress process and the failure mode of specimen at each stage are analyzed.

Study on the transfer and anchorage length of steel strand in ultra high performance concrete material

2020 ◽  
Vol 10 (2) ◽  
pp. 153-164
Author(s):  
Hui Zheng ◽  
Dongdong Zhou ◽  
Xinfeng Yin ◽  
Lei Wang
Keyword(s):  
Bond Strength ◽  
High Performance ◽  
Failure Modes ◽  
High Performance Concrete ◽  
Protective Layer ◽  
Experimental Results ◽  
Ultra High Performance Concrete ◽  
Anchorage Length ◽  
Pull Out ◽  
Steel Strand

Ultra-high-performance concrete (UHPC) material, a new type of cement-based composite material, is usually employed in the bridge engineering. The transfer and anchorage length of steel strand in UHPC material is different from that in ordinary concrete; nevertheless, few design standards are found that how to anchor the transfer and anchoring length of steel strand in UHPC material under normal curing. Through central pull-out test under the different conditions of protective layer thickness and embedded length, the load-slip curves, failure modes, and bond strength of 36 UHPC material specimens under normal curing were studied. The experimental results showed that the ultimate bond stress between UHPC material and steel strand under natural curing conditions is 7.01∼11.68 MPa. When the compressive strength of cube was 157 MPa; the bond strength under natural curing was smaller than that under thermal curing; when the thickness of the protective layer of steel strand with a diameter of 15.2 mm is greater than 30 mm, it had a little influence on bond strength. The regression analysis of the test results based on the experimental results proves that the recommended formulas for the design of transfer length and anchorage length of steel strand in UHPC material were in great agreement with the results of published studies.

Bond Properties of Plain Steel Bar in Concrete with Machine-Made Sand

2013 ◽  
Vol 438-439 ◽  
pp. 20-24
Author(s):  
Feng Lan Li ◽  
Ke Fei Yu ◽  
Xin Xin Ding ◽  
Chang Ming Li
Keyword(s):  
Bond Strength ◽  
Experimental Studies ◽  
Bond Stress ◽  
Test Method ◽  
Bond Properties ◽  
Bond Slip ◽  
Ordinary Concrete ◽  
Strength Grade ◽  
Pull Out ◽  
Steel Bar

To meet the requirement of machine-made sand application in concrete structures, it is necessary to understand the bond properties of steel bar with machine-made sand concrete (MSC). Therefore, the experimental studies were carried out on the bond of plain steel bar with MSC by the central pull-out test method. Three specimens were cast as one group, 6 groups were tested considering the changes of strength grade of MSC and ordinary concrete. The bond-slip curves were measured and analyzed. The results show that the bond slip begins at the tensile side and transfers gradually to the free end before the entire slip turns up along the interface of plain steel bar and surrounded concrete, the largest average bond stress, i. e. the bond strength of plain steel bar corresponds to the initial entire slip of plain steel bar. With the increasing strength grade of MSC and ordinary concrete, the difference of slip at tensile side and free end becomes greater. Comparing that only appears in ordinary concrete with higher strength, the larger slips turn up while the bond stress reaches the largest for the plain steel bar in MSC. Larger scatter of bond strength is between specimens in the same group. Some plain steel bars yields with the beginning of entire slip along the interface.

Bond-Slip Behavior of Steel Bar Embedded in Lightweight Concrete Using Sand Coated Polypropylene Coarse Aggregate

2018 ◽  
Vol 929 ◽  
pp. 103-108 ◽  
Author(s):  
Pamudji Gandjar ◽  
Heribowo Bimasena ◽  
Prayoga Adam Yuta ◽  
Purnomo Heru
Keyword(s):  
Bond Strength ◽  
Coarse Aggregate ◽  
Lightweight Concrete ◽  
Aggregate Gradation ◽  
Bond Slip ◽  
Coarse Aggregates ◽  
Pull Out ◽  
Steel Bar ◽  
Fine Aggregates ◽  
Natural Aggregates

Plastic waste as coarse aggregates in concrete making is part of efforts to reduce environmental pollution. In one hand the use of plastic as aggregates can provide lighter weight of concrete than those using natural aggregates. Accordingly, a comprehensive experimental study on the concrete-steel bond behavior of structural waste polypropylene (PP) lightweight coarse aggregate concrete (WPPLAC) was carried out using different composition, aggregate gradation, type of bar and size diameter of bar. Pull out tests are conducted for three kind of plain and deformed steel bars having diameter 10, 12 and 16 mm respectively, which are embedded in concrete cubes made by the two mixtures to know local bond-slip relation. Two mixtures of sand coated polypropylene (PP) coarse plastic aggregates, sand as fine aggregates, water and Portland Composite Cement with a water-cement ratio of 0.264 are conducted. The first mixture contains 100% of 25 mm sand coated coarse aggregate while the second mixture contains 70% of 25 mm and 30% of 20 mm sand coated coarse aggregates. Bond strength versus steel displacements results in general show that higher bond strength is found for steel bar having larger diameter while steel displacements approximately follow the scale of bar diameter.

Coarse Aggregate Replacement Ratio on the Properties of Recycled Concrete Bonding Effect

2014 ◽  
Vol 926-930 ◽  
pp. 533-536
Author(s):  
Fu Bo Cao ◽  
Feng Yun Li
Keyword(s):  
Coarse Aggregate ◽  
Recycled Concrete ◽  
Recycled Aggregate Concrete ◽  
Recycled Aggregate ◽  
Anchorage Length ◽  
Bond Slip ◽  
Pull Out ◽  
Bonding Effect ◽  
Bonding Properties ◽  
The Impact

Through a pull-out test was designed. The load-slip curves between recycled concrete with different recycled coarse aggregate replacement percentage and rebar were recorded. This article studied the impact of different recycled aggregate replacement rate and the anchorage length for the bond strength between the recycled aggregate concrete and reinforced, and provided a beneficial reference for engineering design of recycled concrete structure under similar conditions. Determined the recycled concrete and reinforced the bond-slip constitutive relation. Come to the bonding properties of reinforced recycled concrete with recycled aggregate rate increase gradually decreased in the anchorage length sufficient to meet the design requirements, performance depended on the pull-out strength of reinforced recycled concrete and reinforced the bond.

Experimental Research on Interfacial Bond Performance in Rock Anchor with High-Performance Grouting Medium

2012 ◽  
Vol 517 ◽  
pp. 932-938 ◽  
Author(s):  
Zhi Fang ◽  
Hong Qiao Zhang
Keyword(s):  
Rock Mass ◽  
Bond Strength ◽  
High Performance ◽  
Interfacial Bond ◽  
Interfacial Bond Strength ◽  
Bond Performance ◽  
Pull Out ◽  
Steel Bar ◽  
Reactive Powder ◽  
Ground Anchor

There exist the problems such as low bond strength and bad durability in the ordinary grouting slurry of the ground anchor system at present. The high-performance grouting mediums RPC (Reactive Powder Concrete) and DSP (Densified Systems containing homogeneously arranged ultrafine Particles) would become the potential replacement of grouting medium in ground anchor resulting from their high compressive strength, durability and toughness. Based on a series of pull-out tests on ground anchors with different high-performance grouting medium of RPC and DSP , different bond length in the construction field, the bond performance on the interfaces between anchor bolt (deformed steel bar) and grouted medium as well as between grouted medium and rock mass was studied. The results indicate that the interfacial bond strength between RPC or DSP and deformed steel bolt ranges within 23-31Mpa, far greater than that (about 2-3MPa) between the ordinary cementitious grout and deformed steel bar. Even though the interfacial bond strength between the grouted medium and rock mass of limestone was not obtained in the test since the failure mode was pull-out of those steel bar rather than the interface shear failure between grouted medium and rock mass, the bond stress on the interface reached 6.2-8.38 MPa, also far greater than the bond strength (about 0.1-3MPa) between the ordinary cementitious slurry and rocks.

Bond behaviour of chemically prestressed textile reinforced concrete

2019 ◽  
Author(s):  
Katarzyna Zdanowicz ◽  
Boso Schmidt ◽  
Hubert Naraniecki ◽  
Steffen Marx
Keyword(s):  
Reinforced Concrete ◽  
Bond Strength ◽  
Crack Width ◽  
Research Programme ◽  
Textile Reinforced Concrete ◽  
Self Compacting Concrete ◽  
Bond Behaviour ◽  
Bond Slip ◽  
Laser Sensors ◽  
Pull Out

<p>The bond behaviour of concrete specimens with carbon textile reinforcement was investigated in the presented research programme. Pull-out specimens were cast from self-compacting concrete with expansive admixtures and in this way chemical prestress was introduced. The aim of the research was to compare bond behaviour between prestressed specimens and non-prestressed control specimens. During pull-out tests, the pull-out force and notch opening were measured with a load cell and laser sensors. Further, bond - slip and pull-out force - crack width relationships were drawn and compared for prestressed and non-prestressed specimens. Chemically prestressed specimens reached 24% higher bond strength than non-prestressed ones. It can be therefore concluded, that chemical prestressing positively influences the bond behaviour of concrete with textile reinforcement and thus better utilisation of its properties can be provided.</p>

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 Experimental study on the effect of concrete strength and corrosion level on bond between steel bar and concrete

2021 ◽  
Vol 72 (4) ◽  
pp. 498-509
Author(s):  
Vuong Doan Dinh Thien ◽  
Hung Nguyen Thanh ◽  
Hung Nguyen Dinh
Keyword(s):  
Compressive Strength ◽  
Bond Strength ◽  
Concrete Strength ◽  
Concrete Block ◽  
Bond Stress ◽  
Concrete Compressive Strength ◽  
Pull Out ◽  
Steel Bar ◽  
Stress Degradation ◽  
Slip Displacement

Corrosion of the steel reinforcement bars reduces the area of the steel bar and the bond stress between the steel bars and around concrete that decreases the capacity of concrete structures. In this study, the bond stress between steel bar with a diameter of 12mm and concrete was examined with the effect of different corrosion levels and different concrete grades. A steel bar was inserted in a concrete block with a size of 20×20×20cm. The compressive strength of concrete was 25.6MPa, 35.1MPa, and 44.1MPa. These specimens were soaked into solution NaCl 3.5% to accelerate the corrosion process with different corrosion levels in the length of 60mm. The pull-out test was conducted. Results showed that the bond strength of the corroded steel bar was higher than that predicted from CEB-FIP. Slip displacement and the range of slip displacement at the bond strength were reduced when the concrete compressive strength was increased. The rate of bond stress degradation occurred faster with the increment of the corrosion level when the concrete compressive strength was increased.

scholarly journals Bond strength between stell-concrete and between concretes with different ages in structural rehabilitation

2015 ◽  
Vol 8 (5) ◽  
pp. 604-624
Author(s):  
M. R. DORIA ◽  
A. T. C SALES ◽  
N. F. de A. ANDRADE
Keyword(s):  
Bond Strength ◽  
Fresh Concrete ◽  
Tensile Tests ◽  
Bond Stress ◽  
Vertical Shear ◽  
Hardened Concrete ◽  
Pull Out ◽  
Steel Bar ◽  
Different Ages ◽  
Indirect Tensile

ABSTRACTIn inspections of buildings, it is common to find structures that, well before reaching its useful life longer require repairs and reinforcements. This study examined the bond strength between concrete of different ages and between steel and concrete, focusing on the recovery of reinforced concrete structures. To analyze the bond between concrete of different ages, trials with specimens receiving three different types of treatments at the interface between the concrete were performed: brushing; brushing and mortar equal to concrete of substrate and brushing and epoxy layer. Indirect tensile tests and oblique and vertical shear tests at the interface were made . The bond stress between steel and concrete was evaluated by pull out test under the conditions of the bar inserted in the still fresh concrete and when inserted in the hardened concrete with epoxy. Results showed increased bond strength by indirect tensile stress of 15% and 37%; 4% and 12% for the adherence test by oblique shear, and 108% and 178%, for the testing of vertical shear, respectively, for the specimens whose interfaces have received, in addition to brushing, layer of mortar and epoxy bridge, compared to those who received only brushing. Insignificant loss (about 0.52%) of bond stress was noticed for pull out test of steel bar when compared with test results of the specimens that had steel bar inserted in the concrete in the hardened state with epoxy adhesion bridge, with those who had inserted steel bar in fresh concrete.

scholarly journals The influence of total reinforcement anchorage length on misinterpretation of the impact of hot-dip galvanised steel corrosion on its bond strength with concrete

2016 ◽  
Vol 60 (1) ◽  
pp. 13-20 ◽  
Author(s):  
P. Pokorný ◽  
J. Čech ◽  
P. Tej ◽  
M. Vokáč
Keyword(s):  
Bond Strength ◽  
Negative Impact ◽  
Steel Corrosion ◽  
Anchorage Length ◽  
Pull Out ◽  
Galvanised Steel ◽  
Strength Tests ◽  
Short Test ◽  
The Impact ◽  
Total Reinforcement

Abstract To begin with, the intorduction of this paper summarises literature sources that wrongly interpret results of the bond strength between hot-dip galvanised reinforcements and concrete. The influence of the total reinforcement anchorage length on the bond strength results assessment was studied in detail. The numeric analysis of beam models with various testing anchorage lengths (the analysis input data comprised the results of previous bond strength tests carried out in a laboratory) unambiguously confirmed that when the bond strength between concrete and hot-dip galvanised reinforcement with a sufficient test anchorage length is tested in a beam test, the negative impact of the coating corrosion on bond strength with concrete may be biased. It is more objective to test bond strength with concrete in a pull-out test where a very short test reinforcement anchorage length is set out as a standard.

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