Download or read book BOND STRENGTH CHARACTERISTICS OF DEFORMED REINFORCING STEEL BARS EMBEDDED IN SIFCON STEEL BARS CONCRETE written by ALI MORSI HAMZA and published by . This book was released on 1992 with total page 468 pages. Available in PDF, EPUB and Kindle. Book excerpt: monitored and the modes of bond failure were determined.
Download or read book Bond Behaviour of Steel Reinforcing Bars Embedded in Ultra High Performance Steel Fiber Reinforced Concrete written by Elisabeth Rita Saikali and published by . This book was released on 2019 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Ultra-High-Performance Steel Fiber Reinforced Concrete (UHP-SFRC) is an emerging concrete considered as an optimal, durable material that can substitute conventional concrete owing to its distinct fresh and hardened properties. Thus, it is essential to understand the mechanism of stress transfer between this concrete and conventional reinforcement that permits the composite action of both materials. A four-point bending test program (FPBT) was arranged and conducted on 19 beams designed for the bond development to occur in the constant moment region along a short embedment length in order to achieve a uniform distribution of bond stresses, enabling measurement of bond strength through reverse engineering of beam strength and deformation. Additional material testing was conducted on prisms under 4-point loading in order to extract the mechanical properties for all material mixes considered. The bond-specimens failed either by pullout or by cone formation with minimal deterioration of the concrete cover, illustrating the high confinement provided by the novel concrete surrounding the bar in tension. The bond strength was determined to be directly proportional to the tensile strength capacity of the design mix, where for the strongest material the bond strength was approximately 30 MPa. Moreover, the test results indicated a very ductile flexural beam response accompanied by significant mid-span deflection reaching 27 mm and substantial bar-slip values attaining 19 mm. Different UHP-SFRC mixes, concrete covers, and embedment lengths were considered. A numerical model was developed to simulate the FPBT using a nonlinear finite element analysis platform, VecTor2, with the ability to model this novel concrete. This high bond strength provided by the concrete cover enables a significant reduction in the design development length as compared to what is used today for conventional concrete.
Download or read book Bond Behavior of Reinforcing Steel in Ultra high Performance Concrete written by and published by . This book was released on 2014 with total page 12 pages. Available in PDF, EPUB and Kindle. Book excerpt: This document is a technical summary of the Federal Highway Administration (FHWA) report "Bond Behavior of Reinforcing Steel in Ultra-High Performance Concrete" (FHWA-HRT-14-090). Ultra-high performance concrete (UHPC) has garnered interest from the highway infrastructure community for its greatly enhanced mechanical and durability properties. The objective of this research is to extensively evaluate the factors that affect bond strength between deformed reinforcing bar and UHPC, and to facilitate the development of design guidelines for using field-cast UHPC in innovative connection details. The results of the research effort and the design recommendations for reinforcing bar embedded in UHPC are provided in this TechBrief.
Download or read book Effect of Deformation Porperties on Bond slip Characteristics of Reinforcing Bars written by Ghassan Khaled Jumah and published by . This book was released on 1992 with total page 174 pages. Available in PDF, EPUB and Kindle. Book excerpt: The theory of reinforced concrete is based on stress transfer between steel and concrete. In order for the steel to develop its full yield force in tension, there should be some bond between that steel and the surrounding concrete. With the deformed bars, used in reinforced concrete construction since many decades, the problem of bond was the topic for many research programs dedicated for the investigation of the factors influencing that bond, Some of these factors are : bar size, cover thickness, spacing between embedded bars, and deformation properties of the bar itself. The objective of our research work was to investigate the effect of rib geometry or rib deformation properties on the bond-slip characteristics of deformed reinforcing bars. For that purpose, plain round Grade 60 bars 20.6 mm (0.811 in.) in diameter were machined to simulate #6 bars. Fifty six of these test bars were tested in eccentric pullout tests. The specimen was a concrete block with a 10-in. length and a 12in.xl2in. cross section. The bar was embedded along the 10-in. length and was loaded in tension until failure of the specimen in a V-notch splitting mode, where the test was halted. Such a short embedment length (10 in.^ for the test bar was chosen in order to avoid yielding of the bar and to minimize the difference in tensile stresses between the loaded-end and the free-end of the bar. The load and the free-end slip of the bar was monitored during the test. Seven series of pullout specimens were prepared and tested, and replicates were included to check the reliability of the test setup and the obtained results. In series ONE and FOUR, the main variable was the rib face angle where five rib face angles were investigated, 30, 45, 60, 75, and 90 degrees. The concrete compressive strength in series ONE was 3000 psi while in series SIX, it was 6000 psi. The main variable in series TWO and FIVE was the rib spacing. Five values of rib spacings were investigated, 0.3 in. (0.37 db), 0.35 in. (0.43 dO, 0.4 in. (0.49 db), 0.45 in. (0.55 db), and 0.5 in. (0.62 db). The rib height was investigated in series THREE and SIX with two different concrete compressive strengths, 3000 and 6000 psi respectively. Four values of rib heights were investigated; 0.04 in. (0.05 db), 0.06 in. (0.074 db), 0.08 in. (0.1 db), and 0.1 in. (0.124 db). Based on the test results of the first six series, the values for the variables in the seventh series were decided upon. In this last series, the rib spacing was kept constant and equal to 0.4 in. (0.49 db), and four combinations of rib face angles and rib heights were tested. The first two combinations had a rib face of 45 degrees and two different rib heights, 0.06 in. (0.074 db) and 0.08 in. (0.1 db), while the other two had a rib face angle 60 degrees with two different rib heights, 0.06 in. (0.074db) and 0.08 in. (0.1 db).
Download or read book Improving Development Characteristics of Reinforcing Bars written by Civil Engineering Research Foundation and published by American Society of Civil Engineers. This book was released on 1994 with total page 104 pages. Available in PDF, EPUB and Kindle. Book excerpt: This report describes the development and implications of a new concrete reinforcing bar with significantly improved bond strength.
Download or read book The Mechanics of Bond and Slip of Deformed Reinforcing Bars in Concrete written by Leroy Albert Lutz and published by . This book was released on 1966 with total page 654 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Bond of Reinforcement in Concrete written by fib Fédération internationale du béton and published by fib Fédération internationale du béton. This book was released on 2000-01-01 with total page 448 pages. Available in PDF, EPUB and Kindle. Book excerpt: "In 1993, the CEB Commission 2 Material and Behavior Modelling established the Task Group 2.5 Bond Models. It's terms of reference were ... to write a state-of-art report concerning bond of reinforcement in concrete and later recommend how the knowledge could be applied in practice (Model Code like text proposal)... {This work} covers the first part ... the state-of-art report."--Pref.
Download or read book Bond Strength of Deformed Bars in Tension written by G. C. Reynolds and published by . This book was released on 1982 with total page 23 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book An Investigation of the Bond of Deformed Steel Bars with Concrete written by Betonvereeniging. Commissie voor Uitvoering van Research and published by . This book was released on 1964 with total page 36 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Bond Characteristics of Micro Composite Multi Structural Formable Steel Used in Reinforced Concrete Structures written by and published by . This book was released on 2003 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The bond performance of a unique type of reinforcing steel rebars, claimed to have high corrosion resistance as well as high tensile strength, with concrete was studied. The objective was to investigate the bond behavior of straight rebars made out of this steel, named MMFX, embedded in concrete flexural members and to examine the applicability of the current expressions for bond force to predict the bond capacity of the MMFX bars embedded in concrete. Two phases of experimental investigation was conducted. In the first phase, four beam end specimens were tested and in the second phase eight splice beams were studied. The bond behavior of the MMFX steel bars was found to be similar to that of carbon steel. The bond strength of the MMFX is significantly reduced as the tensile stresses developed in the bar went beyond the proportional limit. Both the ACI code 318-02 equation for bond force and the current equation proposed by the ACI committee 408 for bond force gave conservative prediction for bond force for low stress levels. However, at high stress levels, the prediction of the two equations went to the unconservative side. The non linear behavior of the MMFX stress-strain curve was the reason behind the unconservative prediction. The above two equations were modified to ensure conservative prediction at high stress levels. A second degree best fitting curve was found to be the best to describe the relationship between the splice length and the bond force capacity for both # 6 and # 8 MMFX bars.
Download or read book Effects of Transverse Reinforcement on the Bond Strength of Deformed Bars Embedded in High Strength Concrete written by Maxwell L. Chisala and published by . This book was released on 1993 with total page 266 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Bond of Reinforcement in Eccentric Pullout Silica Fume Concrete Specimens written by Saad Mohannad Sabbah and published by . This book was released on 1997 with total page 324 pages. Available in PDF, EPUB and Kindle. Book excerpt: The work reported in this thesis is the third phase of a multiphase research program conducted at the American University of Beirut to investigate and assess the effect of silica fume on the bond and anchorage characteristics of reinforcing steel bars in high performance concrete (HPC). The objective of the research work was to investigate the effect of specimen type and specimen size on the role of silica fume in the bond strength of the reinforcing bars, and to evaluate the effect of bar size and concrete confinement on the anchorage characteristics of the reinforcing bars in silica fume concrete. The specimen consisted of a deformed bar embedded 25 mm (10 in.) in a 305 mm x 305 mm x 254 mm (12 x 12 x 10 in.) concrete block. The short embedment length was chosen to avoid yielding of the bar before bond splitting failure takes place. The small size of the specimen allowed testing a large number of specimens to cover different variables. The main variables were the percentage replacement by weight of cement by silica fume (0, 4, 8, 12, 16, or 20 percent), the concrete cover over the reinforcing steel bar (25 mm or 50 mm), and the bar size (25 mm or 32 mm). The test results showed that as silica fume content increass, there is a reduction in load-slip stiffness of the specimens regardless of the bar size or concrete cover used. The test results also showed that the bar size does not affect the anchorage characteristics of the reinforcing bars in silica fume concrete. Finally, the results also indicate that the concrete confinement slightly improves the bond resistance in concrete containing more than 10 percent silica fume.
Download or read book Tests of Bond Resistance Between Concrete and Steel written by Willis Appleford Slater and published by . This book was released on 1920 with total page 76 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Bond Strength of Deformed Reinforcing Bars in Plain High strength Concrete and High strength Steel Fibre Reinforced Concrete written by Frédéric-Simon Bérubé and published by . This book was released on 2003 with total page 380 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Effect of Accelerated Corrosion on the Bond Strength of Corrosion Resistant Reinforcing Bars Embedded in Concrete written by Sourav Khatua and published by . This book was released on 2017 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Corrosion of steel reinforcing bars embedded in concrete applications is a major problem all over the world. Effect of corrosion causes metal loss at sections, cracks in the concrete surrounding the reinforcing steel, spalling of cover concrete also leads to de-bonding of reinforcing bar from the concrete. Corrosion cracks in the surrounding concrete leads to loss in bond strength and finally reduce the structural strength and service life of the structure. This problem is consistently observed in structural slab bridges that are exposed to deicing salts during the winters. In the era of 1980's, black convention steel was replaced with epoxy-coated bars as a solution to prevent corrosion in bridge decks. However the advantage of using epoxy coated bars is still uncertain as the bond strength of these type of bars is a concern. Several researchers in the past have highlighted deleterious effect of corrosion on epoxy-coated bars that are damaged during handling. It is necessary to study the use of alternative reinforcing bars as means of corrosion protection in bridge deck applications. There are several corrosion resistant bars that are readily available in the market, but performance of these bars under accelerated corrosion conditions is still unclear. Six different types of bars which include, conventional black bars, epoxy-coated bars, hot dipped galvanizing bars, continuously galvanized bars, stainless steel bars and MMFX bars were studied in this thesis. The objective of this study is to investigate the effect of accelerated corrosion on bond strength of concrete. The bond between concrete and reinforcement bars play a major role in transfer of stresses from concrete to steel. However, corrosion weakens this bond, resulting in weakening of the Reinforced Concrete member. So, it was necessary to investigate the performance of CRR (Corrosion Resistant Bars) embedded in concrete and s ubjected to accelerated corrosion. The effect of addition of polypropylene fibers on the bond strength was studied. A total of 48 prism specimens were cast with CRR bars including the ones with fibers, of which 24 specimens were subjected to accelerated corrosion. The prisms were 6-inch cube with a reinforcing bar at the centre of each specimen. The embedment length of the bar was 2.5 inches at the mid-height of the section. An electrochemical cell was adopted by placing the specimens in a tank containing 5% salt solution with stainless steel cathode surrounding the specimen. The circuit was completed by connecting the cathode and the reinforcing bar to an external power supply. The specimens were subjected to accelerated corrosion for total of 21 days which includes a two-day wetting and one day drying cycle. Impressed current of 0.02A, calculated using Faraday's law to achieve 5% corrosion damage was supplied during the wetting cycle using external power source. The corroded specimens were then tested to investigate the loss of bond strength due to corrosion and capture any improvement in bond strength using polypropylene fibers. It was observed that, corrosion of bars showed serious bond loss leading to reduced pull-out strength with larger slip of the bars relative to the embedded concrete prisms. Addition of polypropylene fibers showed an improvement in the overall performance of the corroded specimens by increasing the load capacity, reducing slip and improving failure mode from brittle to more ductile mode, compared to un-corroded specimens..
Download or read book Effects of Generalized Loadings on Bond of Reinforcing Bars Embedded in Confined Concrete Blocks written by Suthipoul Viwathanatepa and published by . This book was released on 1979 with total page 324 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Bond Stress slip Characteristics of FRP Rebars written by L. Javier Malvar and published by . This book was released on 1994 with total page 45 pages. Available in PDF, EPUB and Kindle. Book excerpt:
