Investigation Of Fiber And Cracking Behavior For Conventional And Ultra High Performance Concretes Using X Ray Computed Tomography

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Investigation Of Fiber And Cracking Behavior For Conventional And Ultra High Performance Concretes Using X Ray Computed Tomography

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Author :
language : en
Publisher:
Release Date : 2015

Investigation Of Fiber And Cracking Behavior For Conventional And Ultra High Performance Concretes Using X Ray Computed Tomography written by and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2015 with categories.

Short Fibre Reinforced Cementitious Composites And Ceramics

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Author : Heiko Herrmann
language : en
Publisher: Springer
Release Date : 2019-01-11

Short Fibre Reinforced Cementitious Composites And Ceramics written by Heiko Herrmann and has been published by Springer this book supported file pdf, txt, epub, kindle and other format this book has been release on 2019-01-11 with Technology & Engineering categories.

This volume shines a new light on short fibre reinfoced cementitious composites and particle reinforced ceramics. It offers insight from various disciplines like civil engineering, material sciences and micro-mechanics, and collects 9 experimental, numerical and theoretical studies written by top researchers in composite concrete science. The book presents the outcome of the EUROMECH 582 colloquium “Short Fibre Reinfoced Cementitious Composites and Ceramics” held 20 – 22 March 2017, Tallinn, Estonia.

Investigation Of Properties Of High Performance Fiber Reinforced Concrete Very Early Strength Toughness Permeability And Fiber Distribution

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Author : Evelina Khakimova
language : en
Publisher:
Release Date : 2017

Investigation Of Properties Of High Performance Fiber Reinforced Concrete Very Early Strength Toughness Permeability And Fiber Distribution written by Evelina Khakimova and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2017 with Fiber-reinforced concrete categories.

Concrete cracking, high permeability, and leaking joints allow for intrusion of harmful solutions, resulting in concrete deterioration and corrosion of reinforcement in structures. The development of durable, high-performance concretes with limited cracking is a potential solution for extending the service life of concrete structures. Further, the use of very early strength durable materials will facilitate rapid and effective repairs, reduce traffic interruptions, and decrease long-term maintenance work. The purpose of this study was to develop low-permeability durable materials that could achieve a very early compressive strength of 3,000 psi within 10 hours. Within the scope of this work, various proportions of silica fume and fly ash and steel and polypropylene fibers were used to evaluate crack control and post-cracking performance. Other characteristics including toughness, residual strength, water permeability of cracked concrete, and fiber distribution were also examined. The study showed that very early strength durable concretes can be achieved with proper attention to mixture components (amounts of portland cement and accelerating admixtures), proportions (water--cementitious materials ratio), and fresh concrete and curing temperatures. Fiber-reinforced concretes with steel fibers had considerably higher toughness and residual strength compared to concretes with polypropylene fibers. Permeability work showed that minor increases in crack width caused large increases in infiltration of solutions. Further, the addition of fibers can facilitate crack width control. An investigation of fiber distribution showed preferential alignment and some clumping of fibers in the specimens and highlighted the need for appropriate specimen size selection, sufficient mixing time, and proper sequencing of concrete ingredients into the mixer for a uniform random fiber distribution. The results indicated that very early strength and durable fiber-reinforced concrete materials can be developed to improve the condition of existing and new structures and facilitate rapid, effective repairs and construction. The addition of fibers enables cracking control. Optimization of mixtures for strength and durability at different ages for specific applications is recommended.

Mechanical Behavior Of High Performance Concretes

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Author :
language : en
Publisher:
Release Date : 1993

Mechanical Behavior Of High Performance Concretes written by and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 1993 with Concrete categories.

Summary report: This report presents a summary of each phase of a 4-year research program of the Strategic Highway Research Program (SHRP), which examined the mechanical behavior of high performance concretes. -- Production of high performance concrete: This report details the laboratory developmental work on producing high performance concrete for highway applications. -- Very early strength (VES)concrete: This report details the laboratory investigation of the mechanical behavior and field trials of high performance concrete for highway applications, and more specifically, VES concrete. -- High early strength (HES) concrete: The objective of this particular investigation is to obtain information on the mechanical behavior of HES concrete and to demonstrate its use under field conditions. -- Very high strength (VHS) concrete: The objective of this particular investigation is to obtain information on the mechanical behavior of VHS concrete. -- High early strength fiber reinforced concrete: This study provides an extensive data base and a summary of a comprehensive experimental investigation on the fresh state and mechanical properties of high early strength fiber reinforced concrete (HESFRC).

A Standard Tensile Testing Procedure For Fiber Reinforced Concrete Frc And Ultra High Performance Fiber Reinforced Concrete Uhp Frc Based On Double Punch Test Dpt

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Author : Shuveksha Tuladhar
language : en
Publisher:
Release Date : 2017

A Standard Tensile Testing Procedure For Fiber Reinforced Concrete Frc And Ultra High Performance Fiber Reinforced Concrete Uhp Frc Based On Double Punch Test Dpt written by Shuveksha Tuladhar and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2017 with categories.

Current test methods such as ASTM 1609, ASTM 1550 and direct tensile test are used for evaluating the mechanical properties of Fiber Reinforced Concrete (FRC) and to determine the quality of mixture in design and construction practice. These test methods show high variability in the results, requires large specimen and complicated test setup. An ideal material test method for FRC should give consistent results in determining mechanical properties such as peak strength and residual strengths. Moreover, current test methods are expensive and time-consuming as more specimens are needed to acquire reliable test results. Double Punch Test (DPT) is a simple, reliable and consistent test method for evaluating the post-cracking behavior of FRC. DPT originally developed to determine the tensile strength of plain concrete, can also be used for evaluation of peak load and post-peak behavior of FRC and Ultra-High-Performance Fiber Reinforced Concrete (UHP-FRC). This method has a simple test setup and is easier to conduct in comparison to other test methods. DPT experimental test results are seen to be more consistent than the other test methods currently in practice. The simplicity of test setup, reliability of results (low scatter due to the higher cracking surface) and smaller specimens (fewer materials used) are the major advantages of using DPT method for evaluation of post cracking response of FRC and UHP-FRC. In this research, the application of double punch test is validated for FRC and the same method has been used and developed to confirm the suitability for UHP-FRC material in determining tensile strength and behavior in post cracking phase. However, there still exist some potential issue in the DPT method that needs to be resolved. The circumferential extensometer that is used to determine the total crack opening displacement in DPT is an expensive instrument. This limits the use of DPT method in most of the industrial and research laboratories. The measurement of crack width and inspection of a number of cracks are the important parameter for evaluating the characteristics of any concrete material. It is time-consuming to measure the crack width in a test by conventional visual inspection and automated crack width measurement is indispensable. This research mainly focuses on the deriving a simple formula for estimating average and maximum crack width using the axial deformation data and optimize the time taken for each DPT test. The relation would remove the need of using the expensive circumferential extensometer for the test. Thus, DPT could be used to evaluate and compare the quality of mixture for FRC and UHP-FRC by using a simple arrangement of LVDTs.

Effect Of Fiber Orientation On Dynamic Compressive Properties Of An Ultra High Performance Concrete

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Author :
language : en
Publisher:
Release Date : 2016

Effect Of Fiber Orientation On Dynamic Compressive Properties Of An Ultra High Performance Concrete written by and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2016 with categories.

Abstract : Casting structural elements with ultra-high performance concrete (UHPC) tends to create preferential fiber alignment, which affects the strength and must be accounted for in design. Fiber orientation effects in tension have been studied extensively, but less work has been performed for compression. This work characterizes the fiber orientation occurring in a typical UHPC beam and how that orientation affects compressive behavior at high strain rates. Specimens (36 total) were cored from the beam and their fiber orientations were non-destructively evaluated using x-ray computed tomography (CT). Fibers showed flow-induced alignment along the length of the beam, with orientation angles in the x, y, and z-directions differing significantly. The perpendicular orientation number was used to describe orientation, as fibers perpendicular to the load were most effective in crack bridging. Cored specimens tested quasistatically achieved compressive strengths of 14.3-23.6 ksi, which appeared to increase with perpendicular orientation number. However, limited data makes this correlation uncertain. Quasistatic strengths were lower than expected due to the use of neoprene pads. Quasistatic strengths of cores tested without pads averaged 26.6 ksi. Dynamic tests at strain rates of 130-200 1/s were performed with a split-Hopkinson pressure bar (SHPB). Dynamic compressive strength ranged from 38.1 ksi to 58.5 ksi and was independent of orientation number, although results suggested that the distribution and orientation of fibers influenced crack formation. The strain at peak stress, a measure of ductility, ranged from 0.0105 to 0.0131 in dynamic tests. Strain at peak stress increased with perpendicular orientation number, but the correlation was weak. Sources of error, including stress non-equilibrium and radial confinement due to inertia, were assessed.

Mechanical Behavior Of High Performance Concretes

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Author :
language : en
Publisher:
Release Date : 1993

Mechanical Behavior Of High Performance Concretes written by and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 1993 with Concrete categories.

Summary report: This report presents a summary of each phase of a 4-year research program of the Strategic Highway Research Program (SHRP), which examined the mechanical behavior of high performance concretes. -- Production of high performance concrete: This report details the laboratory developmental work on producing high performance concrete for highway applications. -- Very early strength (VES)concrete: This report details the laboratory investigation of the mechanical behavior and field trials of high performance concrete for highway applications, and more specifically, VES concrete. -- High early strength (HES) concrete: The objective of this particular investigation is to obtain information on the mechanical behavior of HES concrete and to demonstrate its use under field conditions. -- Very high strength (VHS) concrete: The objective of this particular investigation is to obtain information on the mechanical behavior of VHS concrete. -- High early strength fiber reinforced concrete: This study provides an extensive data base and a summary of a comprehensive experimental investigation on the fresh state and mechanical properties of high early strength fiber reinforced concrete (HESFRC).

Mechanical Behavior Of High Performance Concretes

DOWNLOAD
Author :
language : en
Publisher:
Release Date : 1993

Mechanical Behavior Of High Performance Concretes written by and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 1993 with Concrete categories.

Summary report: This report presents a summary of each phase of a 4-year research program of the Strategic Highway Research Program (SHRP), which examined the mechanical behavior of high performance concretes. -- Production of high performance concrete: This report details the laboratory developmental work on producing high performance concrete for highway applications. -- Very early strength (VES)concrete: This report details the laboratory investigation of the mechanical behavior and field trials of high performance concrete for highway applications, and more specifically, VES concrete. -- High early strength (HES) concrete: The objective of this particular investigation is to obtain information on the mechanical behavior of HES concrete and to demonstrate its use under field conditions. -- Very high strength (VHS) concrete: The objective of this particular investigation is to obtain information on the mechanical behavior of VHS concrete. -- High early strength fiber reinforced concrete: This study provides an extensive data base and a summary of a comprehensive experimental investigation on the fresh state and mechanical properties of high early strength fiber reinforced concrete (HESFRC).

Evaluation Of Ultra High Performance Fiber Reinforced Concrete

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Author : Hamdi Celik Ozylidirim
language : en
Publisher:
Release Date : 2011

Evaluation Of Ultra High Performance Fiber Reinforced Concrete written by Hamdi Celik Ozylidirim and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2011 with Fiber-reinforced concrete categories.

Recently, a new ultra-high-performance fiber-reinforced concrete (UHPC) was introduced into construction. The fibers in UHPC provide tensile capacity across cracks, resulting in high shear capacity in bending members. Typically, additional reinforcement for shear is not required. The Virginia Department of Transportation (VDOT) is experimenting with UHPC to determine the possibility of using it in transportation structures. The first bridge in Virginia to use UHPC beams was the bridge on Route 624 over Cat Point Creek in Richmond County. The specified minimum 28-day compressive strength was 23 ksi and the specified maximum water-cementitious material ratio was 0.2. UHPC with high strength and very low permeability was used in five beams in one of the 10 spans of the bridge. The purpose of this study was to evaluate the use of UHPC in the Route 624 Bridge. This was achieved by (1) observing the casting of UHPC beams; (2) evaluating the material properties of the UHPC; (3) testing a test beam to failure; (4) measuring strains in beams; and (5) noting any deck cracking. The results of the study indicated that the use of the UHPC led to very high strength and high durability attributable to a very low water-cementitious material ratio, low permeability, high resistance to cycles of freezing and thawing, and very tight cracks under load, all of which should provide for a much longer service life compared to the use of conventional concrete. However, because of the high cost of UHPC, more efficient shapes, design requirements, and material and construction specifications need to be developed to make UHPC practical for beams and other uses. The study recommends that UHPC be considered for use in closure pours and beams with optimized cross sections.

Tensile Behaviour Of Ultra High Performance Steel Fiber Reinforced Concrete

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Author : Yuechen Yang
language : en
Publisher:
Release Date : 2019

Tensile Behaviour Of Ultra High Performance Steel Fiber Reinforced Concrete written by Yuechen Yang and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2019 with categories.

Reinforcing bars are provided in reinforced concrete structures on account of conventional concretes negligible resistance to tension. However, corrosion of steel reinforcement inevitably occurs due to carbonation and chloride ingress, which significantly reduces the service life of structures. An alternative to this predicament is now feasible with the advent in cementitious material technologies, such as ultra-high-performance, self-consolidating, steel fiber reinforced concrete (UHP-SFRC). The keystone of safe and economically feasible designs with UHP-SFRC is dependant on its characterization in tension. Thus, in the present work, a detailed research study including both experimental and analytical components was conducted to investigate the tensile behaviour of UHP-SFRC: tensile strength was quantified and correlated through direct tension test (DTT), four-point bending test (FPBT), splitting tensile test, nonlinear finite element analysis and a calibrated empirical expression in relation to cylinder compressive strength. In addition, effects of important parameters on flexural strength including casting methodology, volumetric ratio of steel fibers, aspect ratio of bending prism and prism size were assessed. Moreover, the bilinear stress-strain and stress-crack mouth opening relationships of UHP-SFRC were derived according to the inverse analysis procedures proposed by Annex 8.1 of CSA-S6 (2018) and Annex U of CSA-A23.1 (2019). Furthermore, a nonlinear finite element analysis software, VecTor2, was employed to develop numerical models with the ability to match the response curves obtained from FPBT. Analytical results indicated that cracking strength of UHP-SFRC derived from the inverse analysis method was generally greater than those obtained from direct tension test, splitting tensile test, nonlinear finite element models and the calibrated empirical expression. Additionally, inverse analysis and finite element analysis results indicated that the majority of prisms exhibited tension hardening behaviour with a hardening ratio greater than 1.1 and an ultimate tensile strain greater than 0.1%. In addition to tension tests, a host of non-destructive tests were conducted to assess the physical properties and durability performance of UHP-SFRC.