Download or read book Modeling of Localized Deformation in High and Ultra high Performance Fiber Reinforced Cementitious Composites written by Marta Miletić and published by . This book was released on 2016 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: A low ratio between the compressive strength of concrete and its cost makes concrete one of the most widely used construction materials in civil engineering. Despite of a very good response to compressive stress, concrete exhibits a low tensile strength and limited tensile strain capacity. Adding short discrete fibers to a cementitious matrix can significantly improve its performance under tensile stress, thus ultimately exhibiting a ductile behavior. Nevertheless, in spite of their beneficial properties fiber reinforced cementitious composites remain underutilized in engineering practice. One of the main reasons for this is a lack of an adequate characterization of the tensile behavior as well as a lack of analysis methods that would allow engineers to incorporate fiber reinforced structural concrete elements into their design. Therefore, this dissertation has four key objectives: 1) to computationally model a stress-strain response of high performance fiber reinforced cementitious composites in uniaxial tension and uniaxial compression prior to macro-crack localization, 2) to develop and perform a diagnostic strain localization analysis for high performance fiber reinforced cementitious composites, the results of which can characterize effects of fibers on failure precursors, 3) to devise and perform an experimental program for characterization of ultra-high performance fiber reinforced cementitious composites, and 4) to characterize a full-fledged behavior including stress-strain and stress-crack opening displacement responses of ultra-high performance fiber reinforced cementitious composites in uniaxial tension. To quantify effects of fibers on onset of strain localization in fiber reinforced cementitious composites a combined computational/analytical models have been developed. To this end, linear-elastic multi-directional fibers were embedded into a cementitious matrix. The resulting composite was described by different types of two-invariant non-associated Drucker-Prager plasticity models. In order to investigate effects of a shape of a yield surface and hardening type linear and nonlinear yield surfaces, and linear and nonlinear hardening rules were considered. Diagnostic strain localization analyses were conducted for several plane stress uniaxial tension and uniaxial compression tests on non-reinforced cementitious composites as well as on high performance fiber-reinforced cementitious composites. It was found that presence of fibers delayed the inception of strain localization in all tests on fiber-reinforced composites. Furthermore, presence of fibers exerted a more significant effect on the strain localization direction and mode in uniaxial compression than in uniaxial tension. The main objective of experimental program was to facilitate characterization of the post-cracking tensile behavior of ultra-high performance fiber reinforced cementitious composites. To this end, five different mixes of fiber-reinforced cementitious composites were cast, whereby volumetric fiber content, fiber shape and water to binder ratio were the experimental variables. Two testing methods were adopted, a direct uniaxial tension test and four-point prism bending test. Two different post-cracking behaviors were observed in direct tension tests, softening and strain hardening accompanied with multiple cracking. On the other hand, the response from prism bending tests was less scattered. Several different inverse analyses were carried out to predict stress-strain and stress-crack opening displacement responses in uniaxial tension based on the prism bending tests. The analyses resulted in worthy correlations with the experimental data, thus suggesting that the prism bending test is a viable alternative to a much more challenging to perform direct tension test for ultra-high performance fiber reinforced composites.

Download or read book PRO 30 4th International RILEM Workshop on High Performance Fiber Reinforced Cement Composites HPFRCC 4 written by Antoine E. Naaman and published by RILEM Publications. This book was released on 2003 with total page 580 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Multiscale Modeling of Tensile Behavior of High Performance Fiber Reinforced Cementitious Composites written by Jingu Kang and published by . This book was released on 2016 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: High Performance Fiber-Reinforced Cementitious Composites (HPFRCC) exhibit strain-hardening behavior and multiple cracking up to relatively high levels of tensile strain. Due to its high toughness, and ability to control crack openings, HPFRCC has numerous applications within the civil infrastructure. Most notably, HPFRCC serves as durable construction and repair materials. The objective of this research is the development and validation of lattice models for the analysis of HPFRCC under tensile loadings. The validation exercises include simulations of the finely distributed cracking patterns, the crack counts and widths, and stress-strain responses. This is achieved through a hierarchical, multiscale accounting of the constitutive behaviors of the matrix, fiber, and fiber-matrix interface. The multiscale model is implemented using the concept of a Rigid-Body-Spring Network, in which the individual fibers within the material volume are explicitly modeled. After matrix cracking, the bonded, debonding, and fiber pullout stages are represented according to a micromechanical model. Fibers can be placed within the computational domain irrespective of the discretization of the matrix phase. The approach is computationally efficient since supplementary degrees of freedom are not introduced with the addition of fibers to matrix. An innovative approach is proposed to achieve objective results with respect to discretization of the matrix, in which force transfer along the embedded lengths of fibers is distributed to the associated matrix elements. This is in contrast to models that lump the pullout force at the crack surfaces, which can lead to spurious break-off of matrix particles as the discretization of the matrix is refined. To verify the distributed force approach, simulated pullouts of single fibers are compared with theory and test results for the cases of perfectly-plastic and slip-hardening behavior of the fiber-matrix interface. The process of fiber pullout is simulated and compared to that of a fully discretized fiber modeling approach through the study of pullout forces and conditions local to the fiber embedment lengths. With respect to fracture in multi-fiber composites, the proposed model matches theoretical predictions of post-cracking strength and pullout displacement corresponding to the traction-free condition (i.e. complete fiber pullout). The modeling approach is also applicable to simulating early-age concrete behavior, as observed during restrained ring tests. The steel and concrete rings are represented by an irregular lattice model. The evolution of concrete properties, including stiffness and strength, is based on simple models and experimental results. For simulating cases of steel fiber-reinforced concrete, each fiber is explicitly represented within the concrete ring. The simulation results compare well with the experimental data, including readings from strain gauges attached to the steel rings. As expected, the addition of short fibers prolongs the time to cracking and reduces crack widths. Viability of the model, as a means for analyzing the early-age behavior of FRCC, is discussed. The multiple cracking of HPFRCC specimens produces islands of material interconnected by fiber bridges, which places demands on solution convergence. For this reason, a special event-by-event solution strategy is newly developed in this study. Local to a developing crack, force transfer from the fibers to matrix is updated according to the event-based procedure, resulting in improved numerical stability and the simulation of realistic crack patterns. Crack count and crack size are also simulated for progressively larger levels of tensile strain. Finally, the lattice model is used to simulate the tensile behavior of HPFRCC depending on the distribution of fibers within a specimen. Fibers are distributed according to simple functions or, more realistically, spatially correlated random fields. Simulated cracking behavior is compared with experimental results for increasing levels of tensile strain. It is seen that regions of lower fiber content act as defects that promote larger crack openings and lower resistance to fracture localization. This dissertation presents a computationally efficient approach to representing individual fibers, and their composite behavior, within lattice models of cement-based materials. A hierarchical, multiscale model for HPFRCC is introduced, in which force transfer along each fiber length evolves during crack formation and opening. The proposed spatial representation of the fiber bridging forces provides realistic representations of stress transfer between the fiber and matrix, which is essential for simulating crack openings and crack spacing in HPFRCC.

Download or read book International Workshop on High Performance Fiber Reinforced Cementitious Composites HPFRCC in Structural Applications written by Gregor Fischer and published by . This book was released on 2006 with total page 604 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book High Performance Fiber Reinforced Cement Composites 6 written by Gustavo J. Parra-Montesinos and published by Springer Science & Business Media. This book was released on 2012-01-28 with total page 567 pages. Available in PDF, EPUB and Kindle. Book excerpt: High Performance Fiber Reinforced Cement Composites (HPFRCC) represent a class of cement composites whose stress-strain response in tension undergoes strain hardening behaviour accompanied by multiple cracking, leading to a high strain prior to failure. The primary objective of this International Workshop was to provide a compendium of up-to-date information on the most recent developments and research advances in the field of High Performance Fiber Reinforced Cement Composites. Approximately 65 contributions from leading world experts are assembled in these proceedings and provide an authoritative perspective on the subject. Special topics include fresh and hardening state properties; self-compacting mixtures; mechanical behavior under compressive, tensile, and shear loading; structural applications; impact, earthquake and fire resistance; durability issues; ultra-high performance fiber reinforced concrete; and textile reinforced concrete. Target readers: graduate students, researchers, fiber producers, design engineers, material scientists.

Download or read book Tension Stiffening in Reinforced High Performance Fiber Reinforced Cement Based Composites written by Daniel Mauricio Moreno Luna and published by . This book was released on 2014 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Cement-based composites, such as concrete, are extensively used in a variety of structural applications. However, concrete exhibits a brittle tensile behavior that could lead to reduced durability and structural performance in the long term. The use of discontinuous fibers to reduce the brittleness of the concrete, and improve its post-cracking tensile behavior, has been a focus of structural materials research since the 1960's. Cement-based materials reinforced with short discontinuous fibers are known as Fiber Reinforced Composites (FRC). High Performance Fiber Reinforced Cement-based Composites (HPFRCC) are a special type of FRC materials that exhibit tensile strain-hardening behavior under varied types of loading conditions such as direct tension or bending. The use of HPFRCC materials in structural applications has shown to improve not only durability and long term performance, but also has proven to enhance inelastic load-deformation behavior, ductility, energy dissipation and shear capacity. The use of HPFRCC materials can also result in a potential reduction of steel reinforcement required for both flexure and shear relative to traditional reinforced concrete structures. The interaction between the mild steel and the ductile HPFRCC matrix in tension was investigated in contrast to that of normal weight concrete. The measured responses demonstrated both the tension stiffening effects of HPFRCC materials as well as the early strain hardening and fracture of the reinforcing bar relative to that in a normal weight concrete observed through full specimen response up to fracturing of the reinforcement. All of the HPFRCC specimens tested exhibited multiple cracking in uniaxial tension. Splitting cracks observed in the concrete at low specimen strain levels and in HyFRC and SC-HyFRC specimens at higher specimen strain levels contributed to the spreading of strain along the reinforcing bar in those specimens, resulting in a larger displacement capacity relative to the ECC specimens, which did not exhibit splitting cracks. Early strain hardening is hypothesized to be the reason for the additional strength observed in specimens subjected to flexure where the interaction between the steel and the HPFRCC matrix plays an important role in the load-displacement response. A modified approach for estimating the flexural capacity of a section of reinforced HPFRCC using experimental tension stiffening data was proposed and demonstrated to improve the accuracy of flexural capacity predictions. Two-dimensional finite element modeling approaches using a total strain based constitutive model were investigated. The numerical simulations demonstrated the relevance of using standard characterization tests to define the tensile and compressive stress-strain curves for the material constitutive model. The simulations capture the initial and post cracking stiffness, load at first cracking, load and strain at localization and deformation capacity observed in the experiments. Multiple cracking was observed in the numerical simulations for the ECC and HyFRC. The models were able to simulate the cracking progression and localization of strains at primary and secondary cracks for the ECC and the HyFRC. The numerical simulations that used the splitting bond-slip model captured the distribution of the strains in the steel better than perfect bond and pull-out bond-slip models as the slip in the interface allowed for a less localized failure of the specimens, especially in the ECC models. The models were also able to accurately capture the early hardening behavior observed in the experiments. A methodology to estimate the flexural strength of HPFRCC structural components by using numerical simulation of tension stiffening has been proposed and validated on a high performance fiber reinforced concrete (HPFRC) infill panel and ECC and HyFRC beams. This methodology serves as an extension of the methodology proposed using experimental tension stiffening results. In the absence of additional experiments, numerical simulation is proposed. A good level of accuracy has been found between the predicted and actual flexural capacities of the investigated components. The proposed methodology is based on the current assumptions from planar analysis used in the calculation of flexural strength in reinforced concrete components.

Download or read book Multifield based Modeling of Material Failure in High Performance Reinforced Cementitious Composites written by D. F. Mora and published by . This book was released on 2013 with total page 150 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Numerical Modeling of High Performance Fiber Reinforced Cementitious Composites written by Martin Trüb (Bauingenieur) and published by . This book was released on 2011 with total page 231 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Strain Hardening Cement Composites Structural Design and Performance written by Kanakubo Toshiyuki and published by Springer Science & Business Media. This book was released on 2012-09-25 with total page 95 pages. Available in PDF, EPUB and Kindle. Book excerpt: Strain Hardening Cement Composites, SHCC hereafter, demonstrate excellent mechanical behavior showing tensile strain hardening and multiple fine cracks. This strain hardening behavior improves the durability of concrete structures employing SHCC and the multiple fine cracks enhance structural performance. Reliable tensile performance of SHCC enables us to design structures explicitly accounting for SHCC’s tensile properties. Reinforced SHCC elements (R/SHCC) indicate large energy absorbing performance under large seismic excitation. Against various types of loads, R/SHCC elements can be designed by superimposing re-bar performance and SHCC’s tensile performance. This report focuses on flexural design, shear design, FE modeling and anti-seismic design of R/SHCC elements as well as application examples. Establishing design methods for new materials usually leads to exploring application areas and this trend should be demonstrated by collecting actual application examples of SHCC in structures.

Download or read book Behavior Modeling and Impact of Bond in Steel Reinforced High performance Fiber reinforced Cement based Composites written by Matthew J. Bandelt and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: High-performance fiber-reinforced cement-based composites (HPFRCCs) are a class of cement-based materials that exhibit a psuedo strain-hardening behavior in uniaxial tension after first cracking, and retain residual strength in compression after crushing. The unique mechanical properties of HPFRCCs have led researchers to investigate their use in structural applications where damage tolerance and energy dissipation is needed. Research on structural applications of steel reinforced HPFRCCs members has shown enhanced damage tolerance, shear capacity, flexural strength, inelastic deformation capacity, and life cycle performance. Recent research has focused on the interaction between mild steel reinforcement and HPFRCCs for modeling and design purposes. When reinforced HPFRCCs have been subjected to direct tension, early strain hardening and reinforcement strain localization have been observed caused by short debonded lengths, as opposed to long debonded lengths in traditional reinforced concrete. Short debonded lengths caused the HPFRCC reinforcement to fracture at lower levels of specimen deformation compared to reinforced concrete. This recent research indicates that bond strength between reinforcement and HPFRCCs may be higher than that of traditional reinforced concrete. Additionally, reinforcement tensile strains may be an important consideration for design and modeling of reinforced HPFRCC structural components. In this dissertation, the bond behavior between steel reinforcement and HPFRCCs is presented through experimental testing and numerical simulations. Bond experiments were conducted under monotonic and cyclic loading conditions where the HPFRCC material surrounding the reinforcement was in a flexural tension stress state. Monotonic test results show that bond strengths are 37% higher, on average, in reinforced HPFRCCs than in reinforced concrete. Additionally, bond-slip toughness (i.e., the area under the bond stress versus reinforcement slip curve) is higher in reinforced HPFRCCs than in reinforced concrete. Cyclic bond-slip experiments were performed for two types of HPFRCCs and compared to monotonic behavior using beam-end specimens. Results show that bond deterioration occurs in HPFRCCs after the maximum bond stress is reached, causing bond stress to reduce by 60%, on average. The loss of bond capacity and bond-slip toughness is due to combined crushing and splitting of the interface. The effects of bond on structural performance are examined through a study on monotonic and cyclic performance of reinforced HPFRCC beam specimens with varying reinforcement ratios. It is shown that cyclic deformation histories can decrease deformation capacity by up to 67%. Unlike traditional reinforced concrete, deformation capacity of reinforced HPFRCCs is shown to increase with increasing longitudinal reinforcement ratio. Results show that the difference between monotonic and cyclic deformation capacity becomes smaller as reinforcement ratio increases. Suggestions are made for providing a moderate amount of reinforcement to take full of advantage of the HPFRCC material toughness and improve structural performance and deformation capacity. An interface bond-slip material model is proposed based on the experimental results to model the interaction between steel reinforcement and HPFRCC materials. Simulations with the proposed interface model are compared with perfect bond models in finite element simulations by comparing numerical and experimental responses of reinforced HPFRCC structural members. Simulations are conducted on reinforced HPFRCC components under monotonic and cyclic deformation histories, and on members with varying reinforcement ratios. Including the proposed interface material model reduces variability in simulated deformation capacity, and leads to a consistent response in terms of cracking patterns and deformation capacity. A methodology is proposed to predict reinforced HPFRCC deformation capacity by examining reinforcement strains, modeling the interface conditions, and implementing a cyclic fracture energy material parameter from test data. The dissertation concludes with suggestions for future research that can extend the work presented herein. Suggestions for future work include additional experimental, numerical, and design-related research.

Download or read book TENSILE STRAIN HARDENING OF HIGH PERFORMANCE FIBER REINFORCED CEMENT BASED COMPOSITES written by PRIJATMADI TJIPTOBROTO and published by . This book was released on 1991 with total page 476 pages. Available in PDF, EPUB and Kindle. Book excerpt: very desirable load-deformation behavior known as "strain hardening" which is an increase in load carrying capacity with increasing strain up to the peak-load.

Download or read book PRO 6 3rd International RILEM Workshop on High Performance Fiber Reinforced Cement Composites HPFRCC 3 written by Hans Wolfgang Reinhardt and published by RILEM Publications. This book was released on 1999 with total page 726 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Structural Behavior and Modeling of High performance Fiber reinforced Cementitious Composites for Earthquake resistant Design written by and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Computational Modelling of Concrete and Concrete Structures written by Günther Meschke and published by CRC Press. This book was released on 2022-05-22 with total page 1500 pages. Available in PDF, EPUB and Kindle. Book excerpt: Computational Modelling of Concrete and Concrete Structures contains the contributions to the EURO-C 2022 conference (Vienna, Austria, 23-26 May 2022). The papers review and discuss research advancements and assess the applicability and robustness of methods and models for the analysis and design of concrete, fibre-reinforced and prestressed concrete structures, as well as masonry structures. Recent developments include methods of machine learning, novel discretisation methods, probabilistic models, and consideration of a growing number of micro-structural aspects in multi-scale and multi-physics settings. In addition, trends towards the material scale with new fibres and 3D printable concretes, and life-cycle oriented models for ageing and durability of existing and new concrete infrastructure are clearly visible. Overall computational robustness of numerical predictions and mathematical rigour have further increased, accompanied by careful model validation based on respective experimental programmes. The book will serve as an important reference for both academics and professionals, stimulating new research directions in the field of computational modelling of concrete and its application to the analysis of concrete structures. EURO-C 2022 is the eighth edition of the EURO-C conference series after Innsbruck 1994, Bad Gastein 1998, St. Johann im Pongau 2003, Mayrhofen 2006, Schladming 2010, St. Anton am Arlberg 2014, and Bad Hofgastein 2018. The overarching focus of the conferences is on computational methods and numerical models for the analysis of concrete and concrete structures.

Download or read book Advances in Design and Implementation of Cementitious Backfills ADICB written by Erol Yilmaz and published by Frontiers Media SA. This book was released on 2022-10-05 with total page 102 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Strain Hardening Cement Based Composites written by Viktor Mechtcherine and published by Springer. This book was released on 2017-09-04 with total page 811 pages. Available in PDF, EPUB and Kindle. Book excerpt: This is the proceedings of the 4th International Conference on Strain-Hardening Cement-Based Composites (SHCC4), that was held at the Technische Universität Dresden, Germany from 18 to 20 September 2017. The conference focused on advanced fiber-reinforced concrete materials such as strain-hardening cement-based composites (SHCC), textile-reinforced concrete (TRC) and high-performance fiber-reinforced cement-based composites (HPFRCC). All these new materials exhibit pseudo-ductile behavior resulting from the formation of multiple, fine cracks when subject to tensile loading. The use of such types of fiber-reinforced concrete could revolutionize the planning, development, dimensioning, structural and architectural design, construction of new and strengthening and repair of existing buildings and structures in many areas of application. The SHCC4 Conference was the follow-up of three previous successful international events in Stellenbosch, South Africa in 2009, Rio de Janeiro, Brazil in 2011, and Dordrecht, The Netherlands in 2014.

Download or read book High Performance Fiber Reinforced Cement Composites 6 written by Gustavo J. Parra-Montesinos and published by Springer. This book was released on 2012-02-29 with total page 559 pages. Available in PDF, EPUB and Kindle. Book excerpt: High Performance Fiber Reinforced Cement Composites (HPFRCC) represent a class of cement composites whose stress-strain response in tension undergoes strain hardening behaviour accompanied by multiple cracking, leading to a high strain prior to failure. The primary objective of this International Workshop was to provide a compendium of up-to-date information on the most recent developments and research advances in the field of High Performance Fiber Reinforced Cement Composites. Approximately 65 contributions from leading world experts are assembled in these proceedings and provide an authoritative perspective on the subject. Special topics include fresh and hardening state properties; self-compacting mixtures; mechanical behavior under compressive, tensile, and shear loading; structural applications; impact, earthquake and fire resistance; durability issues; ultra-high performance fiber reinforced concrete; and textile reinforced concrete. Target readers: graduate students, researchers, fiber producers, design engineers, material scientists.