Download or read book Multi scale Pull out Behaviors of Fiber and Steel Reinforcing Bar in Hybrid Fiber Reinforced Concrete written by Alexander Lin and published by . This book was released on 2017 with total page 119 pages. Available in PDF, EPUB and Kindle. Book excerpt: For a reinforced concrete structural member, sufficient bond between steel reinforcing bar and concrete guarantees a steel/concrete composite behavior, which is essential for a good overall member performance. Under severe loading, high slippage between rebar and concrete leads to matrix cracking and crushing in the bond region followed by degradation of the rebar/matrix bond. Fiber reinforcement provides a fiber bridging mechanism to resist such cracking behavior by modifying the tensile properties of the matrix. This thesis investigated a deflection hardening hybrid fiber reinforced concrete (HyFRC) with micro/macro fiber hybridization and recommends it as a matrix to enhance the rebar/matrix bond by utilizing its superior crack resisting ability. In the experimental phase, the rebar bond behaviors in ordinary concrete (OC), HyFRC without/with high volume fly ash and Engineered Cementitious Composites (ECC), another type of fiber reinforced cement-based composite (FRCC) with hardening behavior, were studied. The experimental program consists of monotonic and cyclic rebar pull-out test series and was supported by digital image correlation (DIC) and vibration test techniques. Different specimens were made by varying some conditions such as rebar size (no. 4 and no. 8) and absence/presence of transverse reinforcement (spiral) so the effect of such conditions in regards to bond between rebar and different matrices can also be studied. In addition to experiments, Finite element models were developed to further investigate the mechanical behavior of the HyFRC matrix during rebar pull-out and to examine how a transverse steel reinforcement affects such behavior. The experimental results showed that HyFRC can improve the rebar pull-out behavior by changing the failure mode from brittle splitting failure to a more ductile frictional pull-out failure compared to the OC material. The HyFRC material without fly ash provided better rebar bond performance compared to OC with spiral reinforcement and other type of FRCC under investigation. Compared to the monotonic rebar pull-out behavior, only minimal amount of additional damage was induced in such HyFRC material by repeated loading and unloading process from cyclic loading protocol. DIC measurement indicated that the width of the splitting cracks that form in HyFRC matrices due to rebar pull-out could be further reduced when such specimens were confined by spirals. The finer the splitting cracks, the higher the rebar gripping stress and hence the higher the rebar pull-out resistance. The DIC measurement was consistent with the results from finite element analysis because both of them showed that confining the HyFRC matrix with transverse steel reinforcement led to a more uniform distribution of the splitting crack width during rebar pull-out. The vibration test showed that rebar pull-out induced similar degree of damage in the bond regions of HyFRC with and without transverse reinforcement. If severe macrofiber pull-out occurs within the cracks induced by rebar pull-out, the macrofibers become less effective in resisting such cracks. Therefore, good macrofiber pull-out resistance in HyFRC is essential for an improved rebar pull-out performance. To investigate the macrofiber pull-out behavior and how it is affected by the presence of PVA microfibers in HyFRC, single fiber pull-out tests were conducted for various mortar mixtures. In some of these mortars, the cement was replaced by industrial by-products, such as fly ash and slag. In addition, macrofiber pull-out behavior in an ultra-high strength concrete with and without steel microfiber reinforcement was also studied. The results of the single fiber pull-out tests revealed that the presence of PVA microfibers in a mortar mixture designed based on the HyFRC mixture enhances the steel macrofiber pull-out resistance. This synergy between micro and macrofibers provided a more effective control of the splitting cracks and was responsible for the superior rebar bond performance. Hence, the research revealed a multi-scale bond enhancement in a HyFRC member reinforced by steel rebar. The macrofiber pull-out behaviors from mortars in which 45% and 15% of cement were replaced by slag and fly ash, respectively, showed that slag densified the steel macrofiber/matrix interface and hence, improved the pull-out resistance for the macrofiber. On the other hand, test results of fiber pull-out specimens in which 55% of cement was replaced by fly ash showed that increasing curing age made the PVA microfiber reinforcement less effective in resisting steel macrofiber pull-out. Such characteristic showed how high-volume fly ash weakened the PVA fiber/matrix bond. This mechanism induced by fly ash made PVA fibers in HyFRC less effective in improving steel macrofiber pull-out resistance and hence, reduced the micro/macro fiber synergy, which is beneficial for the rebar bond behavior. Therefore, using high volume fly ash decreased the rebar pull-out resistance in HyFRC. When steel macrofibers were pulled out from extremely strong matrices, almost no microcracks formed around macrofibers and the steel microfiber reinforcement didn’t affect the macrofiber pull-out behavior because such microfibers function by bridging the microcracks.

Download or read book Advances in Engineered Cementitious Composite written by Y. X. Zhang and published by Woodhead Publishing. This book was released on 2022-02-26 with total page 562 pages. Available in PDF, EPUB and Kindle. Book excerpt: Advances in Engineered Cementitious Composite: Materials, Structures and Numerical Modelling focuses on recent research developments in high-performance fiber-reinforced cementitious composites, covering three key aspects, i.e., materials, structures and numerical modeling. Sections discuss the development of materials to achieve high-performance by using different type of fibers, including polyvinyl alcohol (PVA), polyethylene (PE) polypropylene (PP) and hybrid fibers. Other chapters look at experimental studies on the application of high-performance fiber-reinforced cementitious composites on structures and the performance of structural components, including beams, slabs and columns, and recent development of numerical methods and modeling techniques for modeling material properties and structural behavior. This book will be an essential reference resource for materials scientists, civil and structural engineers and all those working in the field of high-performance fiber-reinforced cementitious composites and structures. Features up-to-date research on [HPFRCC], from materials development to structural application Includes recent experimental studies and advanced numerical modeling analysis Covers methods for modeling material properties and structural performance Explains how different types of fibers can affect structural performance

Download or read book On Enhancing the Mechanical Behavior of Ultra high Performance Concrete Through Multi scale Fiber Reinforcement written by William F. Heard and published by . This book was released on 2021 with total page 22 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Computational Modelling of Concrete Structures written by Günther Meschke and published by CRC Press. This book was released on 2018-01-31 with total page 1034 pages. Available in PDF, EPUB and Kindle. Book excerpt: The EURO-C conference series (Split 1984, Zell am See 1990, Innsbruck 1994, Badgastein 1998, St. Johann im Pongau 2003, Mayrhofen 2006, Schladming 2010, St. Anton am Arlberg 2014, and Bad Hofgastein 2018) brings together researchers and practising engineers concerned with theoretical, algorithmic and validation aspects associated with computational simulations of concrete and concrete structures. Computational Modelling of Concrete Structures reviews and discusses research advancements and the applicability and robustness of methods and models for reliable analysis of complex concrete, reinforced concrete and pre-stressed concrete structures in engineering practice. The contributions cover both computational mechanics and computational modelling aspects of the analysis and design of concrete and concrete structures: Multi-scale cement and concrete research: experiments and modelling Aging concrete: from very early ages to decades-long durability Advances in material modelling of plain concrete Analysis of reinforced concrete structures Steel-concrete interaction, fibre-reinforced concrete, and masonry Dynamic behaviour: from seismic retrofit to impact simulation Computational Modelling of Concrete Structures is of special interest to academics and researchers in computational concrete mechanics, as well as industry experts in complex nonlinear simulations of concrete structures.

Download or read book Multiscale Characterization of Advanced Pavement Materials written by Dawei Wang and published by Frontiers Media SA. This book was released on 2023-10-20 with total page 133 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Local Bond Stress slip Behavior of Reinforcing Bars Embedded in Fiber Reinforced Concrete written by Marwan Mohamed Hout and published by . This book was released on 1992 with total page 138 pages. Available in PDF, EPUB and Kindle. Book excerpt: This study summarizes experimental results of the local bond stress-slip relationship of reinforcing bars embedded in fiber reinforced concrete (FRC). More than 70 bond specimens were tested and the effect of several parameters on the local bond stress-slip behavior was investigated. These include, size of reinforcing bar (#6 and #8); type of fibers (hooked steel, polypropylene); volume fraction of fibers Vf (between 0.9% and 1.4ft for the steel fibers, 1.5% for the polypropylene fibers); type of specimen (pullout, beam); and confinement (confined, unconfined). Whereas the primary emphasis was on the monotonic local bond stres3-slip response, some specimens were tested under large slip reversals to study the effect of fibers on the cyclic bond stress-slip behavior. The results showed that the addition of fibers to concrete matrixes improves the bond characteristics of ordinary reinforcing bar3. For specimens in which bond failure was by pull-out, adding steel fibers in 2% by volume fraction increased the maximum local bond resistance by about 15%. However, the intrinsic shape of the local bond stre33-slip behavior does not change in comparison with conventional concrete. Furthermore, the addition of fibers to concrete matrixes does not seem to influence the stiffness degradation characteristics of the local bond stress-slip response under cyclic 1oading compared to conventiona1 confined concrete reported in technical literature.

Download or read book Steel Fiber Reinforced Concrete written by Harvinder Singh and published by Springer. This book was released on 2016-10-26 with total page 181 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book discusses design aspects of steel fiber-reinforced concrete (SFRC) members, including the behavior of the SFRC and its modeling. It also examines the effect of various parameters governing the response of SFRC members in detail. Unlike other publications available in the form of guidelines, which mainly describe design methods based on experimental results, it describes the basic concepts and principles of designing structural members using SFRC as a structural material, predominantly subjected to flexure and shear. Although applications to special structures, such as bridges, retaining walls, tanks and silos are not specifically covered, the fundamental design concepts remain the same and can easily be extended to these elements. It introduces the principles and related theories for predicting the role of steel fibers in reinforcing concrete members concisely and logically, and presents various material models to predict the response of SFRC members in detail. These are then gradually extended to develop an analytical flexural model for the analysis and design of SFRC members. The lack of such a discussion is a major hindrance to the adoption of SFRC as a structural material in routine design practice. This book helps users appraise the role of fiber as reinforcement in concrete members used alone and/or along with conventional rebars. Applications to singly and doubly reinforced beams and slabs are illustrated with examples, using both SFRC and conventional reinforced concrete as a structural material. The influence of the addition of steel fibers on various mechanical properties of the SFRC members is discussed in detail, which is invaluable in helping designers and engineers create optimum designs. Lastly, it describes the generally accepted methods for specifying the steel fibers at the site along with the SFRC mixing methods, storage and transport and explains in detail methods to validate the adopted design. This book is useful to practicing engineers, researchers, and students.

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 Computational Modelling of Concrete Structures written by Nenad Bicanic and published by CRC Press. This book was released on 2014-03-04 with total page 1120 pages. Available in PDF, EPUB and Kindle. Book excerpt: The EURO-C conference series (Split 1984, Zell am See 1990, Innsbruck 1994, Badgastein 1998, St Johann im Pongau 2003, Mayrhofen 2006, Schladming 2010, St Anton am Alberg 2014) brings together researchers and practising engineers concerned with theoretical, algorithmic and validation aspects associated with computational simulations of concrete and

Download or read book Local Bond Stress slip Relationship of Reinforcing Bars Embedded in Fiber Reinforced Concrete Under Splitting Type Failure written by Walid Jalkh and published by . This book was released on 1993 with total page 150 pages. Available in PDF, EPUB and Kindle. Book excerpt: This study summarizes experimental results of the local bond stress-slip response of reinforcing bars embedded in fiber reinforced concrete (FRC) under splitting type failure. Pullout specimens were tested to study the effect of several parameters, namely, type, volume fraction, and aspect ratio of fibers, concrete cover to reinforcing bars (or splitting area surrounding the reinforcing bar), and size of reinforcing bar. The experimental results showed that the major contribution of fibers is in the post-splitting range. As compared to plain concrete, the bond behavior of fiber reinforced concrete is more ductile inasmuch as the post-splitting bond stresses are increased. This increase is function of the fiber reinforcing index and of the fiber bond characteristics. The results from the current study were combined with other results reported in technical literature and used to develop a model to describe the bond stress-slip relationship of reinforcing bars embedded in plain and FRC under splitting type failure. The model accounts for all of the important parameters that tend to influence the bond characteristics of reinforcing bar3 as observed in the experiment. It should be mentioned that this study consists the second pact of a two-phase experimental program dealing with the local bond stress-slip characteristics of reinforcing bars embedded in fiber reinforced concrete. While this current phase concentrates on the splitting type of failure, the first part of the study (Ref. 4) emphasized pullout failure.

Download or read book First RILEM International Conference on Concrete and Digital Fabrication Digital Concrete 2018 written by Timothy Wangler and published by Springer. This book was released on 2018-08-29 with total page 334 pages. Available in PDF, EPUB and Kindle. Book excerpt: Digital fabrication has been termed the “third industrial revolution”, and is promising to revolutionize many disciplines, including most recently the construction sector. Both academia and industry see immense promise in cementitious materials, which lend themselves well to additive manufacturing techniques for digital fabrication in construction. With this recent trend and high interest in this new research field, the 1st RILEM International Conference on Concrete and Digital Fabrication (Digital Concrete 2018) was organized. Since 2014, ETH Zurich has been host for the Swiss National Centre for Competence in Research (NCCR) for Digital Fabrication in Architecture, which is highly interdisciplinary and unique worldwide. In 2018, this NCCR opened the “DFAB House”, which incorporates many digital fabrication principles for architecture. It is also responsible for the 600 m2 Robotic Fabrication Lab and the first robotically built roof in the world. Held in tandem with Rob|Arch 2018, the leading conference for robotics in architecture, RILEM deemed it the right time to combine forces at this new conference, which will be the first large conference to feature the work of the recently created RILEM Technical Committee on Digital Fabrication with Cement-based Materials, among other leaders in this new field worldwide. This conference proceedings brings together papers that take into account the findings in this new area. Papers reflect the varying themes of the conference, including Materials, Processing, Structure, and Applications.

Download or read book Tensile Behavior of Ultra high Performance Fiber Reinforced Concrete and Reinforcement Bar written by Corey P. Hollmann and published by . This book was released on 2014 with total page 344 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Interaction Modeling in Mechanized Tunneling written by Günther Meschke and published by Springer Nature. This book was released on 2023-03-17 with total page 477 pages. Available in PDF, EPUB and Kindle. Book excerpt: This open access book compiles the research results of the Collaborative Research Center SFB 837, which has been running since 2010 and will end in 2022, with the topic "Interaction Modeling in Mechanized Tunneling". The Collaborative Research Center is funded by the German Research Foundation (DFG) and is currently the world's largest research facility in the field of tunneling. The aim of the publication is to make our scientific findings accessible to the international professional community. The individual chapters deal with all subsystems relevant in mechanized tunneling and their interaction. The latest results of digital planning and real-time tunneling support have been included.

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 High performance Hybrid fibre Concrete written by Ivan Marković and published by IOS Press. This book was released on 2006 with total page 232 pages. Available in PDF, EPUB and Kindle. Book excerpt: "In the research project presented in this PhD-thesis, an innovative type of fibre concrete is developed, with improved both the tensile strength and the ductility: the Hybrid-Fibre Concrete (HFC). The expression "Hybrid" refers to the "hybridisation" of fibres: short and long steel fibres were combined together in one concrete mixture. This is opposite to conventional steel fibre concretes, which contain only one type of fibre. The basic goal of combining short and long fibres is from one side to improve the tensile strength by the action of short fibres, and from the other side to improve the ductility by the action of long fibres." "In this research project, all important aspects needed for the development and application of Hybrid-Fibre Concrete have been considered. In total 15 mixtures, with different types and amounts of steel fibres were developed and tested in the fresh state (workability) as well as in the hardened state (uniaxial tensile tests, flexural tests, pullout tests of single fibres and compressive tests). A new analytical model for bridging of cracks by fibres was developed and successfully implemented for tensile softening response of HFC. At the end, the utilisation of HFC in the engineering practice was discussed, including a case-study on light prestressed long-span beams made of HFC."--BOOK JACKET.

Download or read book Fibre Reinforced Cementitious Composites Second Edition written by Arnon Bentur and published by CRC Press. This book was released on 2006-11-22 with total page 625 pages. Available in PDF, EPUB and Kindle. Book excerpt: Advanced cementitious composites can be designed to have outstanding combinations of strength (five to ten times that of conventional concrete) and energy absorption capacity (up to 1000 times that of plain concrete). This second edition brings together in one volume the latest research developments in this rapidly expanding area. The book is split into two parts. The first part is concerned with the mechanics of fibre reinforced brittle matrices and the implications for cementitious systems. In the second part the authors describe the various types of fibre-cement composites, discussing production processes, mechanical and physical properties, durability and applications. Two new chapters have been added, covering fibre specification and structural applications. Fibre Reinforced Cementitious Composites will be of great interest to practitioners involved in modern concrete technology and will also be of use to academics, researchers and graduate students.

Download or read book fib Model Code for Concrete Structures 2010 written by fib - federation internationale du beton and published by John Wiley & Sons. This book was released on 2013-12-04 with total page 434 pages. Available in PDF, EPUB and Kindle. Book excerpt: The International Federation for Structural Concrete (fib) is a pre-normative organization. 'Pre-normative' implies pioneering work in codification. This work has now been realized with the fib Model Code 2010. The objectives of the fib Model Code 2010 are to serve as a basis for future codes for concrete structures, and present new developments with regard to concrete structures, structural materials and new ideas in order to achieve optimum behaviour. The fib Model Code 2010 is now the most comprehensive code on concrete structures, including their complete life cycle: conceptual design, dimensioning, construction, conservation and dismantlement. It is expected to become an important document for both national and international code committees, practitioners and researchers. The fib Model Code 2010 was produced during the last ten years through an exceptional effort by Joost Walraven (Convener; Delft University of Technology, The Netherlands), Agnieszka Bigaj-van Vliet (Technical Secretary; TNO Built Environment and Geosciences, The Netherlands) as well as experts out of 44 countries from five continents.