scholarly journals Bond Strength of Fusion Bonded Epoxy-Coated Reinforcement in Concrete

2019 ◽  
Vol 5 (3) ◽  
pp. 255
Author(s):  
G M Sadiqul Islam ◽  
Ehsan Ahmed ◽  
Md. Sabbir Hossain ◽  
S. M. Sharif Uddin
Keyword(s):  
Bond Strength ◽  
Concrete Strength ◽  
Epoxy Coating ◽  
Test Results ◽  
Reinforced Concrete Structure ◽  
Reinforcing Bars ◽  
Strength Based ◽  
Modification Factor ◽  
Bar Diameter ◽  
Bond Characteristics

Fusion-bonded epoxy-coated steel is expected to extend the service life of the reinforced concrete structure in chloride-laden environments. However, the effect of coating on the bond-strength between rebar and concrete is not well understood yet. This research, therefore, studied the effect of epoxy-coating on the bond characteristics of reinforcing bars in concrete. The bond characteristics were assessed through pullout test considering variables viz. concrete strength, embedded length and bar diameter. The load was applied to reinforcing bars embedded in concrete until bond strength between the bar and concrete exceeded. Bond strength of epoxy-coated bars was compared with that of the uncoated bars. It was found that epoxy-coating reduced the bond strength approximately 25% for Ø20mm bar and 12% for Ø16mm and Ø12mm bar. As with uncoated bar, bond strength of coated bars were also increased with concrete strength. However, the bond strength ratio between coated and uncoated bars was found almost independent of concrete strength. Based on the test results, a development length modification factor of 1.33 is proposed for Ø20mm bar and 1.15 for Ø12mm and Ø16mm bar to compensate the bond strength reduction due to the epoxy coating.

scholarly journals Bond Strengths of Geopolymer and Cement Concretes

2010 ◽  
Vol 69 ◽  
pp. 143-151 ◽  
Author(s):  
Prabir Sarker
Keyword(s):  
Reinforced Concrete ◽  
Bond Strength ◽  
Concrete Cover ◽  
Reinforced Concrete Structures ◽  
Geopolymer Concrete ◽  
Reinforcing Steel ◽  
Test Results ◽  
Reinforcing Bars ◽  
Pull Out ◽  
Bar Diameter

Geopolymer is an inorganic alumino-silicate product that shows good bonding properties. Geopolymer binders are used together with aggregates to produce geopolymer concrete which is an ideal building material for infrastructures. A by-product material such as fly ash is mixed together with an alkali to produce geopolymer. Current research on geopolymer concrete has shown potential of the material for construction of reinforced concrete structures. Structural performance of reinforced concrete depends on the bond between concrete and the reinforcing steel. Design provisions of reinforced concrete as a composite material are based on the bond strength between concrete and steel. Since geopolymer binder is chemically different from Ordinary Portland Cement (OPC) binder, it is necessary to understand the bond strength between geopolymer concrete and steel reinforcement for its application to reinforced concrete structures. Pull out test is commonly used to evaluate the bond strength between concrete and reinforcing steel. This paper describes the results of the pull out tests carried out to investigate the bond strength between fly ash based geopolymer concrete and steel reinforcing bars. Beam end specimens in accordance with the ASTM Standard A944 were used for the tests. In the experimental program, 24 geopolymer concrete and 24 OPC concrete specimens were tested for pull out. The concrete compressive strength varied from 25 to 55 MPa. The other test parameters were concrete cover and bar diameter. The reinforcing steel was 500 MPa steel deformed bars of 20 mm and 24 mm diameter. The concrete cover to bar diameter ratio varied from 1.71 to 3.62. It was found from the test results that the failure occurred by splitting of concrete in the region bonded with the steel bar, in both geopolymer and OPC concrete specimens. Comparison of the test results shows that geopolymer concrete has higher bond strength than OPC concrete. This suggests that the existing design equations for bond strength of OPC concrete with steel reinforcing bars can be conservatively used for calculation of bond strength of geopolymer concrete.

Analysis and Design Recommendations for the Collapse of a Concrete Silo

2011 ◽  
Vol 250-253 ◽  
pp. 2877-2880 ◽  
Author(s):  
Guang Lin Yuan ◽  
Lu Dan Tian
Keyword(s):  
Reinforced Concrete ◽  
Concrete Strength ◽  
Structure Design ◽  
Test Results ◽  
Reinforcing Bars ◽  
Design Recommendations ◽  
Analysis And Design ◽  
The Future ◽  
Design And Construction

Accidents of the cement manufacturers’ reinforced concrete silo structures frequently occurred currently in China, because of quality problems, causing enormous losses. The collapse status of a cement raw meal silo is investigated. Combined with the test results of the location and spacing of silo wall’s reinforcing bars, concrete strength, cracks and defects, the reasons for collapse of silo wall are analyzed and design recommendations for concrete silo structures are made. This can give reference to reinforced concrete silo structure design and construction in the future.

Experimental Research on Durability of Concrete of Transmission Lines in Wuhu Area

2014 ◽  
Vol 1065-1069 ◽  
pp. 2001-2004
Author(s):  
Zhao Qing Zhu ◽  
Lin Xu ◽  
Jian Chen ◽  
Zhi Wei Han
Keyword(s):  
Bond Strength ◽  
Transmission Lines ◽  
Concrete Strength ◽  
Field Tests ◽  
Windward Side ◽  
Leeward Side ◽  
Test Results ◽  
Concrete Deterioration ◽  
Rebar Corrosion ◽  
Corrosive Environments

The concrete used in transmission lines are basically for foundations. The foundation concrete of transmission lines in corrosive environments has shown serious deterioration, which usually caused by concrete deterioration, rebar corrosion, degradation of bond strength between rebar and concrete due to various corrosive effects. Field tests are carried out in Wuhu area to research the durability of foundation concrete of transmission lines. And test results show that the concrete strength in the air is a litter higher than underground and the carbonization depth at the windward side is the largest of each foundation and the leeward side is the smallest, while those underground are close to zero.

scholarly journals Estimation of compressive strength based on Pull-Out bond test results for on-site concrete quality control

2011 ◽  
Vol 4 (4) ◽  
pp. 582-591 ◽  
Author(s):  
M. S. Lorrain ◽  
M. P. Barbosa ◽  
L. C. P. Silva Fº
Keyword(s):  
Quality Control ◽  
Compressive Strength ◽  
Concrete Strength ◽  
Test Results ◽  
Compression Tests ◽  
Pull Out ◽  
Underlying Principle ◽  
Strength Based ◽  
Concrete Quality ◽  
Definition Of

Quality control of structural concrete has been conducted for several decades based mainly on the results of axial compression tests. This kind of test, although widely used, is not exempt from errors and has some considerable drawbacks that may affect its reliability, such as the need for appropriate and careful specimen conditioning and adoption of adequate capping techniques. For these reasons, it would be useful to have complementary or alternative ways to check compressive strength, in order to improve concrete quality control. The use of a bond test to monitor concrete strength is being proposed by an international group of researchers from France, Tunisia and Brazil as a potential means to this end. Given the fact that the link between bond resistance and concrete strength is already well established, this type of test seems to be a viable alternative to traditional methods. Nonetheless, to check if the underlying principle is sound when used in different circumstances, the group has been gathering data from several studies conducted by different researchers in various countries, with distinct concretes and rebar types. An analysis of the data collected shows that there is a clear and strong correlation between bond resistance and compressive strength, no matter the influence of other variables. This result validates the basic idea of using an Appropriate Pull-Out (APULOT) bond test to assess concrete strength. If the general principle is valid for random data obtained from different studies, the definition of a clear and appropriate test will probably lead to the reduction of experimental noise and increase the precision of the strength estimates obtained using this method.

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.

Experimental Results of Polyester/Glass Fibers – Cementitious Matrix Bond Characteristics: Effect of Silane on Fibers

2012 ◽  
Vol 428 ◽  
pp. 73-77
Author(s):  
Nor Edine Abriak ◽  
Nassim Sebaibi ◽  
Mahfoud Benzerzour
Keyword(s):  
Bond Strength ◽  
Unsaturated Polyester ◽  
Glass Fibers ◽  
Experimental Program ◽  
Silane Treatment ◽  
Test Results ◽  
Toughening Mechanism ◽  
Fiber Pullout ◽  
Cementitious Matrix ◽  
Bond Characteristics

In this paper, the effect of silane treatment on the bond characteristics of fiber in cementitious matrix, including bond strength and pullout energy are presented. These fibres arise from recycling by crushing of thermoset composite based on unsaturated polyester/glass fiber. Various silane treatment contents ranging from 0% to 1% are used. This treatment by silane enhances the fiber–matrix interfacial properties, especially in fiber pullout energy. However, the bond strength was increased by 150% and the pullout energy was increased by 300%. It is also concluded that in terms of the bond characteristics, the optimal content of silane is 0.5%, given the conditions of the experimental program. The micro structural observation confirms the findings on the interfacial-toughening mechanism drawn from the fiber pullout test results.

scholarly journals Bond strength of epoxy coated bar splices confined with nominal lateral reinforcement

2013 ◽  
Vol 3 (1) ◽  
Author(s):  
Krishnamurthy Pandurangan ◽  
Gangolu Rao
Keyword(s):  
Bond Strength ◽  
Primary Objective ◽  
Reduction Factor ◽  
Full Scale ◽  
Epoxy Coating ◽  
Transverse Reinforcement ◽  
Test Results ◽  
Bar Test ◽  
Lateral Reinforcement ◽  
Constant Moment

AbstractFusion bonded epoxy coating is one of the methods used to protect steel against corrosion. The primary objective of this research reported in this paper is to evaluate the bond strength of epoxy coated bar splices confined with lateral reinforcement. Six full scale beams specimens, designed to fail in bond- splitting mode, were tested in positive bending. Each beam was reinforced with bars spliced in the constant moment region at mid span. The main variables were the amount of transverse reinforcement in the splice region and the coating to the bar. Test results indicate that transverse reinforcement improves the bond strength of coated bars and the ductility of the beams. The bond strength of coated bars is 93%, 72% and 59% of uncoated bars for confinement indices of 1.8, 1.4 and 1.26 respectively. Moreover, a bond reduction factor of 1.35 is suggested for use in code in place of 1.5,when the confinement index is greater than 1.4.

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