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Category : Pavements
Languages : en
Pages : 164
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Performance and environmental data continued to be monitored throughout this study on the Ohio SHRP Test Road. Response testing included three new series of controlled vehicle tests and two sets of nondestructive tests. Cracking in two SPS-2 sections with lean concrete base confirmed observations elsewhere that PCC pavement may not perform well when placed on rigid base. Of the five types of base material used on LOG 33 and evaluated for their effect on AC pavement performance, deflection measurements on the asphalt treated base fluctuated most with changes in temperature. None of the other bases were sensitive to temperature. Cement treated base had the lowest deflection. On unbound material, bases containing large size stone gave the lowest deflection. The preponderance of data collected in the laboratory and at the ERI/LOR 2 site suggests that PCC pavement performs poorly on 307 NJ and CTFD bases. All sections with 25-foot slabs, except those with ATFD base, and the section with 13-foot slabs on 307 NJ base had significant transverse cracking. The 13-foot long slabs with 307 NJ base also had some longitudinal cracking. Considering the relatively short time these pavement sections had been in service, this level of performance was considered unacceptable. The ATFD base appeared to be performing best. On JAC/GAL 35, subgrade stiffness had a significant effect on dowel bar response. Looseness around dowel bars affected their ability to transfer load. Larger diameter and stiffer dowel bars provided better load transfer across PCC joints. The most effective dowel bar in these tests was the 1.5" diameter steel bar. The performance of 1" steel dowel bars were similar to 1.5" fiberglass bars. One-inch diameter fiberglass dowel bars were not recommended for PCC pavement. While undercutting PCC joint repairs initially reduced the forces in dowel bars, the effectiveness of the undercut diminished over time. Dowel bar forces were about the same in the Y and YU types of joint repairs after some time.
Author: Shad M. Sargand
Publisher:
ISBN:
Category : Nondestructive testing
Languages : en
Pages : 184
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In 1994-96, the Ohio Department of Transportation (ODOT) constructed a 3.5-mile long test pavement on US 23 in Delaware County for the Strategic Highway Research Program. This project contained a total of 40 test sections of asphalt concrete and Portland cement concrete pavement in the SPS-1, SPS-2, SPS-8 and SPS-9 experiments of the Specific Pavement Studies program. These experiments were designed to assess the effectiveness of different base types and thicknesses, different pavement thicknesses and other design parameters on the structural performance of highway pavements. During the construction of these sections, the Falling Weight Deflectometer (FWD) was used to measure the composite stiffness of the sections as each new material layer was completed and accepted by ODOT. In addition, the Dynaflect trailer was used to measure the composite stiffness of the completed sections prior to their being opened to traffic. The overall objectives of this research study were to evaluate the stiffness of the test sections on this experimental pavement as the new material layers were added to the sections, and to evaluate various analysis software packages currently available for the backcalculation of layer moduli. While the Ohio SHRP Test Road was constructed in an area of flat terrain believed to have relatively uniform subgrade, FWD measurements indicated considerable subgrade variability between sections and within individual sections. None of the subgrade sections was considered to be good, about half were fair and the other half were poor to very poor. As expected, much of the variability was mitigated as successive material layers were placed in the sections, and especially with the addition of stabilized materials. Stiffness equivalencies were developed for the six types of base material used on the test road, and for AC and PCC pavement used on these bases. The final stiffness of the completed sections was consistent with early performance, in that the first six asphalt concrete sections which failed had the highest measured deflections with both the FWD and Dynaflect just prior to being opened to traffic. An excellent correlation was developed between FWD and Dynaflect output on the completed asphalt concrete pavement sections and clear trends were also apparent on PCC pavement, though the limited range of readings on PCC with both devices made it difficult to develop a definitive correlation on rigid pavement. The stiffness of the completed AC and PCC pavement sections, and load transfer across PCC pavement joints were quite similar when measured with the FWD and Dynaflect, demonstrating the usefulness of both instruments in evaluating structural performance. Four elastic layer programs were evaluated for their ability to calculate the moduli of the various material layers in the 40 test sections. Of these, MODULUS 4.2 performed the best and was the most user friendly program to run. To obtain consistent results on any specific project, a standard operating procedure needs to be developed for those conditions and the analysis program being used, and the procedure needs to be closely followed for all calculations.
Author:
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ISBN:
Category : Pavements, Concrete
Languages : en
Pages : 300
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In Phase I, the research team contacted each of 16 participating states to gather information about concrete and concrete material tests. A preliminary suite of tests to ensure long-term pavement performance was developed. The tests were selected to provide useful and easy-to-interpret results that can be performed reasonably and routinely in terms of time, expertise, training, and cost. The tests examine concrete pavement properties in five focal areas critical to the long life and durability of concrete pavements: (1) workability, (2) strength development, (3) air system, (4) permeability, and (5) shrinkage. The tests were relevant at three stages in the concrete paving process: mix design, preconstruction verification, and construction quality control. In Phase II, the research team conducted field testing in each participating state to evaluate the preliminary suite of tests and demonstrate the testing technologies and procedures using local materials.
Author:
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ISBN:
Category :
Languages : en
Pages : 88
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Author:
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ISBN:
Category :
Languages : en
Pages : 84
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Author:
Publisher:
ISBN:
Category : Highway engineering
Languages : en
Pages : 100
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Author:
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ISBN:
Category :
Languages : en
Pages : 124
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Author:
Publisher:
ISBN:
Category : Highway research
Languages : en
Pages : 84
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Author:
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ISBN:
Category : Government publications
Languages : en
Pages : 248
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Author: United States. Congress. House. Committee on Appropriations. Subcommittee on Department of Transportation and Related Agencies Appropriations
Publisher:
ISBN:
Category : Political Science
Languages : en
Pages : 1284
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