Evaluation of High-Performance Fiber-Reinforced Concrete for Bridge Deck Connections, Closure Pours, and Joints
Evaluation of High-Performance Fiber-Reinforced Concrete for Bridge Deck Connections, Closure Pours, and Joints

Author: Levon C. Hoomes

Publisher:

Published: 2017

Total Pages: 22

ISBN-13:

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Connections, closure pours, and joints in bridges are often sources of distress because of cracks and openings. Wide separation facilitates the penetration of harmful solutions that can lead to costly repairs. Cracks are caused by volumetric changes attributable to moisture and temperature and the application of service loads after the concrete has hardened. Poor bonding between the existing concrete and new concrete can lead to separation or opening. Wide cracks or openings within the material or at the interface and leaking joints allow the ingress of water and chemicals, causing damage to the bridge deck sections and the bridge substructure through corrosion of reinforcing steel, alkali-silica reactions, sulfate attack, and freeze-thaw damage. This study was designed to evaluate properties of fiber-reinforced concrete and cementitious composites in controlling cracking for bridge deck closure pours (i.e., link slabs). Plastic and hardened mixture properties of high-performance fiber-reinforced concrete (HPFRC) were evaluated, with emphasis on deflection hardening, flexural toughness, and bond strength. A secondary objective was to evaluate various bond strength tests for use in prequalification or quality assurance of mixtures. The addition of a small amount of discontinuous fibers to a conventional concrete matrix minimizes cracking, but the size of these cracks still permits the intrusion of harmful solutions. High volumes of suitable fibers used in HPFRC produce multiple very tight cracks (

High-performance Fiber-reinforced Concrete in a Bridge Deck
High-performance Fiber-reinforced Concrete in a Bridge Deck

Author: Hamdi Celik Ozyildirim

Publisher:

Published: 2005

Total Pages: 15

ISBN-13:

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The purpose of this research was to compare the performance of high-performance fiber-reinforced concrete (FRC) with that of conventional concrete in a bridge deck. FRC is expected to increase toughness, provide enhanced residual strength, and minimize the occurrence and width of cracking in bridge decks. This report describes the development and testing of concrete mixtures containing synthetic fibers in the laboratory and the plant and the placement in the deck of the bridge carrying Route 11 over the Maury River in Lexington, Virginia. The deck was on steel beams. FRC was placed over one of the four piers. Comparisons with the control section without the fibers over a 5-year period indicated that FRC has fewer and narrower cracks, even though higher shrinkage occurred in the FRC specimens. Evaluation of fibers in continuous decks, especially over steel beams, should continue. However, particular attention must be devoted to mixture proportioning, slump, and air content. Further, the workability lost by the addition of fibers should be regained by the addition of a high-range water-reducing admixture, not water, or durability may decrease. Fibers can control cracking and minimize corrosion of the reinforcement in the concrete, thus extending the service life of the structure and reducing maintenance costs, leading to substantial savings.

Evaluation of Ultra-high-performance Fiber-reinforced Concrete
Evaluation of Ultra-high-performance Fiber-reinforced Concrete

Author: Hamdi Celik Ozylidirim

Publisher:

Published: 2011

Total Pages: 20

ISBN-13:

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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.

Ultra-high Performance Fiber Reinforced Concrete in Bridge Deck Applications
Ultra-high Performance Fiber Reinforced Concrete in Bridge Deck Applications

Author: Jun Xia

Publisher:

Published: 2011

Total Pages: 145

ISBN-13:

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The research presented in this dissertation focuses on the material characterization of ultrahigh performance fiber reinforced concrete (UHP-FRC) at both the microscopic and macroscopic scales. The macroscopic mechanical properties of this material are highly related to the orientation of the steel fibers distributed within the matrix. However, the fiber orientation distribution has been confirmed to be anisotropic based on the flow-casting process. The orientation factor and probability density function (PDF) of the crossing fiber (fibers crossing a cutting plane) orientation was obtained based on theoretical derivations and numerical simulations with respect to different levels of anisotropy and cut planes oriented arbitrarily in space. The level of anisotropy can be calibrated based on image analysis on cut sections from hardened UHP-FRC prisms. Simplified equations provide a framework to predict the mechanical properties based on a single fiber-matrix interaction rule selected from existing theoretical models. Along with the investigation of the impacts from different curing methods and available post-cracking models, a versatile parameterized uniaxial stress-strain constitutive model was developed and calibrated. The constitutive model was implemented in a finite element analysis software program, and the program was utilized in the preliminary design of moveable bridge deck panels made of passively reinforced UHP-FRC. This deck system was among the several alternatives to replace the problematic steel grid decks currently in use. Based on experimental investigations of the deck panels, failure occurred largely in shear rather than flexure during bending tests. However, this shear failure is not abrupt and usually involves large deformation, large sectional rotation, and wide shear cracks before loss of load-carrying capacity. This particular shear failure mode observed was further investigated numerically and experimentally. Three-dimensional FEM models with the ability to reflect the interaction between rebar and concrete were created in a commercial FEM software to investigate the load transfer mechanism before and after bond failure. Small-scale passively reinforced prisms were tested to verify the conclusions drawn from simulation results. In an effort to improve the original design, several shear-strengthened deck panels were tested and evaluated for effectiveness. Finally, methods and equations to predict the ultimate shear capacity were calibrated. A two-dimensional frame element based complete moveable bridge finite element model was built for observation of bridge system performance. The model contained the option to substitute any available deck system based on a subset of pre-calibrated parameters specific to each deck type. These alternative deck systems include an aluminum bridge deck system and a glass fiber reinforced plastic (GFRP) deck system. All three alternatives and the original steel grid deck system were evaluated based on the global responses of the moveable bridge, and the advantages and disadvantages of adopting the UHP-FRC deck system are quantified.

Engineered Fibre-reinforced Concrete Systems for Bridge Deck Link Slab Applications
Engineered Fibre-reinforced Concrete Systems for Bridge Deck Link Slab Applications

Author: James F. Cameron

Publisher:

Published: 2014

Total Pages: 133

ISBN-13:

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Rehabilitation and maintenance of the aging transportation infrastructure are of major concern in the Province of Ontario. A large portion of this work is related to the durability of highway bridges around the province. One of the weakest points in a bridge structure from a durability aspect is the expansion joints that can allow harmful elements, such as road salts and contaminants to leak down from the road surface and attack the supporting structure of the bridge. Although expansion joints can be eliminated in the design of a new bridge, such as in an integral abutment bridge, this requires major changes to the supports and structure of the bridge, making it impractical for retrofitting existing bridges. One effective alternative is the replacement of a traditional expansion joint with a link slab. A link slab is a concrete slab used in place of an expansion joint to make the bridge deck continuous while keeping the supporting girders simply supported. Link slabs must be able to resist large force effects both in bending and direct tension while minimizing cracking, one solution is to use the high tensile and flexural strength properties of an ultra-high performance fibre-reinforced concrete (UHPFRC). The UHPFRC mixtures are often proprietary and expensive. The purpose of this research was to evaluate the potential of using common fibre types with standard concrete ingredients in a fibre-reinforced concrete (FRC) as an alternative to UHPFRC in a link slab.

Innovative Bridge Designs for Rapid Renewal
Innovative Bridge Designs for Rapid Renewal

Author: HNTB Corporation, Genesis Structures Inc, Structural Engineering Associates, and Iowa State University

Publisher: Transportation Research Board

Published:

Total Pages: 976

ISBN-13: 0309274109

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This report from the second Strategic Highway Research Program (SHRP 2), which is administered by the Transportation Research Board of the National Academies, documents the development of standardized approaches to designing and constructing complete bridge systems for rapid renewals.

Exploring Fiber-reinforced Polymer Concrete for Accelerated Bridge Construction Applications
Exploring Fiber-reinforced Polymer Concrete for Accelerated Bridge Construction Applications

Author: Carolyn Donohoe

Publisher:

Published: 2022

Total Pages: 0

ISBN-13:

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The use of prefabricated superstructure elements in bridge construction reduces on-site construction time, improves work-zone safety, and can reduce overall project costs. For prefabricated elements to be used efficiently for accelerated bridge construction (ABC), the precast components, such as deck panels or decked-bulb tees, must be connected quickly on-site, ideally using as little additional material as possible. The use of fiber-reinforced polymer concrete (FRPC) was explored as a closure pour material for bridges to connect adjacent precast superstructure elements. Polymer concretes have been used successfully as a non-structural overlay material in transportation systems for many decades. With the addition of fibers, FRPC displays levels of two critical characteristics, bond and tension strength, that are comparable to other alternatives, such as ultra-high performance concrete (UHPC). While UHPC may still provide the best solution in many instances, FRPC has the advantage of requiring shorter closure windows (approximately 4 hours versus 72 hours for UHPC) due to the very rapid strength gain of the polymer, which could be ideal for overnight construction or rehabilitation projects. The bond and mechanical properties of FRPC were determined at several temperatures, spanning the range of typical service conditions in western Washington State. Tests were completed measuring the compressive, flexural, and bond strength of FRPC. Then, a central composite rotatable experimental design was utilized to explore the impact of splice length, side cover, bar size, and temperature on bar stress in non-contact splice specimens. The test setup was similar to that completed by the Federal Highway Administration (FHWA) with UHPC. The results of the testing program indicate that FRPC exhibits significant variation in mechanical properties with temperature, roughly -0.6 %/°F; the development of early compressive, flexure, and bond strengths were very similar, reaching roughly 70% of their 7-day values in 4 hours; and peak bar stresses in non-contact lap splices embedded in FRPC were comparable to UHPC for the embedded lengths tested. Based on the testing results, example joint configurations for connecting precast superstructure elements were developed, enabling the comparison of FRPC with alternative closure pour materials for future ABC projects.

Development of a Mix Design Adjustment Method for Fiber Reinforced Concrete and Super High-performance Concrete Based on Excess Paste
Development of a Mix Design Adjustment Method for Fiber Reinforced Concrete and Super High-performance Concrete Based on Excess Paste

Author: Joe Malloy

Publisher:

Published: 2019

Total Pages: 154

ISBN-13:

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The main objective of this study was to develop a mix design adjustment method for Fiber Reinforced Concrete (FRC) that would maintain appropriate workability while improving hardened concrete performance. A literature review was conducted to examine existing methods for adjusting mix designs to account for fiber introduction. It was found that while increasing fine aggregate and cement paste content can make up for lost workability with the addition of fibers, no rational mix design adjustment method is available. Reference mix designs from the Nevada Department of Transportation and the Nebraska Department of Transportation were used, and this study focused on tailoring the idea of increasing paste and fine aggregate to focus on the parameter of excess paste. Excess paste serves to coat the aggregate particles and is critical for workability. To apply this method of excess paste adjustment, a modified version of ASTM C29 was used to determine the void content of fiber-aggregate skeletons with varying fiber contents. Paste and fine aggregate content were then adjusted to maintain the excess paste quantity between reference mixes and mixes with fiber. A variety of tests including slump, vibrated L-box, compressive strength, splitting tensile strength, flexural strength, drying shrinkage, and restrained shrinkage were conducted to evaluate the overall concrete performance. Results indicated that, for each mix design, adjusting based on excess paste provided a workable FRC with improved hardened performance. Eight slabs were then prepared for a large-scale examination of constructability. Throughout the study of FRC, an alternative concrete to Ultra-High Performance Concrete (UHPC) that would considerably outperform High-Performance Concrete (HPC) was developed. This study delves into the development of a new type of concrete called Super High Performance Concrete (SHPC). SHPC is a high strength, self-consolidating FRC that would significantly cut back on cost and production limitations compared to UHPC as it can be produced with conventional drum-type mixers. Results indicate that SHPC outperforms HPC in matters of workability, compressive strength, flexural strength, and toughness and could potentially be a viable alternative of UHPC for applications such as bridge deck connections and overlays.