Browsing by Subject "Pavement joints"

Now showing 1 - 5 of 5
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    Comparison of Performances of Structural Fibers and Development of a Specification for Using Them in Thin Concrete Overlays
    (Minnesota Department of Transportation, 2018-08) Barman, Manik; Hansen, Bryce
    Structural fibers improve the long-term performance of concrete pavements and overlays and potentially are useful to reduce the slab thickness. These fibers are available in different parent material compositions, stiffness, shapes, and aspect ratios. The main objective of this study was to characterize the post-crack flexural and joint performance of fiber reinforced concrete to develop a specification for the selection of structural fibers for concrete overlays and/or pavements. The study included a literature review, an online survey, and a large-scale laboratory testing. It was found that the majority (almost 94%) of the FRC overlays in this country were constructed with structural synthetic fibers, which provided equal or better performance than projects using the steel fibers. In the laboratory study, a total of 43 different mixes were prepared with 11 different types of fibers. Fiber dosage, stiffness, and geometry significantly influenced the residual strength ratio (RSR) and residual strength (RS). In general, embossed, twisted, and crimped fibers performed better on average than straight-flat synthetic fibers when the comparison was made in terms of RSR or RS. From the joint performance testing, it was found that fibers can greatly improve the performance of the pavement with respect to load transfer efficiency (LTE), differential displacement, and differential joint energy dissipation. The findings from this were used to recommend the target ranges post-crack flexural performance, and joint performance parameters
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    Numerical Assessment of Three-Dimensional Rigid Pavement Joints Under Impact Loads
    (1990-08) Koubaa, Amir; Krauthammer, Theodor
    This study was conducted with the aim of improving the state of knowledge on the behavior of joints in concrete pavements, and to explore the feasibility of developing a non-destructive testing technique based on frequency response of dynamically loaded joints. One of the objectives of this study was to numerically investigate the existence of a relationship between load transfer capacity of a joint in rigid pavements and its dynamic response. The approach adapted for the present study is based on a numerical model which accurately represents the mechanism of shear transfer in reinforced concrete members implemented it in a commercially available finite element code. That tool is then used for the analysis of two models which consisted of various joint conditions. One model represented an ideal condition of full load transfer across a joint, while the other model was used to simulate variable load transfer conditions. The results obtained are analyzed in the time and frequency domains. These results provided a comprehensive description of the joint response characteristics, and enabled the derivation of a clear relationship between the response frequencies and the joint's shear transfer capabilities. The results may be used as the starting point for the development of a precise/non-destructive testing method for a wide range of cases in which shear transfer across discontinuities in concrete systems is a principal load resisting mechanism. Specific conclusions and recommendations on future developments have been provided.
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    Performance Benefits of Fiber-Reinforced Thin Concrete Pavement and Overlays
    (Minnesota Department of Transportation, 2021-07) Barman, Manik; Roy, Souvik; Tiwari, Amarjeet; Burnham, Tom
    This study investigates the performance benefits of synthetic structural fibers in mitigating distresses in thin concrete pavements and overlays. In this study, two ultra-thin (3 and 4 inches thick) and four thin (5 and 6 inches thick) concrete pavements placed on a gravel base along with two thin unbonded concrete overlay cells (5 inches thick) placed on an existing concrete pavement were constructed at the Minnesota Road Research (MnROAD) facility in 2017. This report discusses the objectives and methodology of the research, including the construction of the test cells, instrumentation, traffic load application, and data collection and analysis procedures. The structural responses and distresses observed over three years, such as fatigue cracking and faulting, as well as the joint performance measured in each cell, were discussed and compared in this report.
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    Toward the development of pavement-specific structural synthetic fibers
    (Minnesota Department of Transportation, 2024-06) Barman, Manik; Sabu, Rohith; Sharma, Pranav; Janson, Austin
    Thin fiber reinforced concrete (FRC) pavements and overlays can be economical for low- and moderate-traffic volume roads. Due to insufficient concrete cover thickness, thin concrete pavements or overlays cannot accommodate dowel bars that are typically used in conventional thick concrete pavements. The critical distress for such applications is the transverse joint faulting because of the lack of joint load transfer between the concrete slabs. The currently available synthetic structural fibers can contribute to joint performance to a certain extent. However, as pavements experience significant slab contraction and expansion and carry both wheel and environmental loads, there is a need to design and develop fibers that will provide high joint performance and help mitigate transverse joint faulting when used at an affordable dosage. The overall goal of this study is to develop pavement-specific fibers that will yield the needed joint performance benefits to achieve the intended design life. The study is being conducted in two phases. This report is written for Phase 1 of the study. The study started with a literature review, followed by a finite element analysis, falling weight deflectometer (FWD) data analysis, and laboratory testing of fiber reinforced concrete and individual fibers embedded in concrete. The finite element results and FWD data were amalgamated to quantify the possible joint load transfer of the base layer and foundation, aggregate interlocking, and the needed contribution from the structural fibers. A procedure was established to account for the contribution of the fibers. A new parameter, namely, modulus of fiber support, was introduced to evaluate the stiffness of the fibers that participate in joint load transfer. Notably, a laboratory approach is identified to determine the modulus of fiber support, which can help determine the optimum fiber dosages as well as design and test the pavement-specific fibers in the future phase of the study.
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    Vibration Spectroscopy for Rigid Pavement Joint Assessment
    (1990-08) Palmieri, Lucio; Krauthammer, Theodor
    This study was conducted with the aim of improving the state of knowledge on the behavior of joints in concrete pavements, and to explore the feasibility of developing a non-destructive testing technique based on the frequency response of dynamically loaded joints. One of the objectives of the present study was to experimentally investigate the existence of a relationship between load transfer capacity of a joint in rigid pavements and its dynamic response. the experimental study involved the application of an impact testing approach for the evaluation of two test systems. One system represented an ideal condition of full load transfer across a joint, while the other system was used to simulate variable load transfer conditions. Acceleration-time histories captured from both sides of the joint, under short load pulses, were used for analysis both in the time and frequency domains. These results provided a comprehensive description of the joint response characteristics, and enabled the derivation of a clear relationship between the response frequencies and the joint's shear transfer capabilities. These results may be used as the starting point for the development of a precise non-destructive testing method for a wide range of cases in which shear transfer across discontinuities in concrete systems is a principal load resisting mechanism. Specific conclusions and recommendations on future developments have been provided.