The objectives of this research were to 1) investigate bridge deck condition assessment methods used in the field and laboratory, methods of managing bridge decks, and methods for estimating remaining bridge deck service life using computer models through a comprehensive literature review on these subjects; 2) collect and analyze field data from representative concrete bridge decks in Utah; and 3) develop a decision tree for concrete bridge deck management in Utah. As a result of the literature review performed for objective 1, a synthesis of existing information about condition assessment, bridge deck preservation and rehabilitation, bridge deck reconstruction, and estimating remaining service life using computer models was compiled. For objective 2, 15 bridge decks were strategically selected for testing in this research. Five bridge decks had bare concrete surfaces, five bridge decks had asphalt overlays, and five bridge decks had polymer overlays. Bridge deck testing included site layout, cover depth measurement, chloride concentration testing, chain dragging, half-cell potential testing, Schmidt rebound hammer testing, impact-echo testing, and vertical electrical impedance testing. Two-sample t-tests were performed to investigate the effects of selected bridge deck features, including polymer overlay application, deck age at polymer overlay application, overlay age, asphalt overlay application with and without a membrane, stay-in-place metal forms (SIPMFs), SIPMF removal, internally cured concrete, and use of an automatic deck deicing system. For objective 3, condition assessment methods were described in terms of test type, factors evaluated, equipment cost, data collection speed, required expertise, and traffic control for each method. Unit costs, expected treatment service life estimates, and factors addressed for the preservation, rehabilitation, and reconstruction methods most commonly used by the Utah Department of Transportation (UDOT) were also summarized. Bridge deck testing results were supplemented with information about current bridge deck management practices and treatment costs obtained from UDOT, as well as information about condition assessment and expected treatment service life, to develop a decision tree for concrete bridge deck management. Based on the results of field work and statistical analyses, placing an overlay within a year after construction is recommended. Removing SIPMFs after a deck age greater than 18 years is not likely to be effective at reversing the adverse effects of the SIPMFs on bridge deck condition and is not recommended. Bridge deck construction using internally cured concrete is not recommended for protecting against rebar corrosion. To the extent that excluding an automatic deck deicing system does not compromise public safety, automatic deck deicing systems are not recommended. To supplement the typical corrosion initiation threshold of 2.0 lb Cl-/yd3 of concrete for black bar, a corrosion initiation threshold of 8.0 lb Cl-/yd3 of concrete is recommended in this research for bridge decks with intact epoxy-coated rebar. For chloride concentrations less than 20 lb Cl-/yd3 of concrete as measured between reinforcing bars, an increase of up to 70 percent should be applied to estimate the corresponding chloride concentration of the concrete in direct contact with the rebar. The decision tree developed in this research includes 10 junctions and seven recommended treatments. The junctions require the user to address questions about surface type, degree of protection against water and chloride ion ingress, degree of deterioration, and years of additional service life needed; the answers lead to selection of treatment options ranging from repairing an overlay to full-depth bridge deck reconstruction. Revisions to the decision tree should be incorporated as additional methods, data, treatments, or other relevant information become available.

京都大学 / 0048 / 新制・課程博士 / 博士(工学) / 甲第21355号 / 工博第4514号 / 新制||工||1703(附属図書館) / 京都大学大学院工学研究科社会基盤工学専攻 / (主査)教授 KIM Chul-Woo, 教授 杉浦 邦征, 講師 張 凱淳 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DFAM

The purpose of this research was to identify the types of joints available for use on concrete bridge decks and to investigate the performance characteristics of each type, including primary functions and movement ranges. Eleven reports on joint performance published by state departments of transportation and universities nationwide were analyzed in order to obtain information on joint performance problems typically encountered by state transportation agencies. In addition, test methods and specifications provided by the American Society for Testing and Materials (ASTM) were reviewed for application by bridge engineers to ensure the adequacy of deck joints. The research indicates that compression seals should be used to accommodate movements less than 2 in., while strip seals should be used for movements up to 4 in. A lubricant conforming to ASTM D 4070, Standard Specification for Adhesive Lubricant for Installation of Preformed Elastomeric Bridge Compression Seals in Concrete Structures, should be applied during installation of compression and strip seals. Finger joints with troughs should be used instead of reinforced elastomeric joints and modular elastomeric joints for movements greater than 4 in. To maximize the performance of finger joints, ensuring adequate structural properties of the finger plates and proper installation of the troughs is necessary. When Utah Department of Transportation (UDOT) engineers conduct in-house experiments on bridge deck joints in the future, they should be more consistent and provide more information about the bridge structures in reports, including, for example, the anticipated deck movements, average daily traffic, and design loads for the bridges. Also, UDOT should establish a consistent evaluation program for investigating joint products during the approval process. The program should include quantitative measurements including, but not limited to, debris accumulation, adhesion and cohesion of the joint material, condition of anchorages and header materials, watertightness of the joints, condition of the concrete edges of the deck, deterioration of substructures, ride quality, noise level under travel, and general appearance of the joints. These experimental data should then be thoroughly documented in the resulting reports.

Bridge engineers and managers in coastal areas and cold regions frequently specify the application of surface treatments on concrete bridge decks as barriers against chloride ingress. In consideration of concrete cover thickness and the presence of stay-in-place metal forms (SIPMFs), the objective of this research was to determine the latest timing of initial surface treatment applications on concrete bridge decks subjected to external chloride loading before chlorides accumulate in sufficient quantities to initiate corrosion during the service life of the deck. Chloride concentration data for this research were collected from 12 concrete bridge decks located within the I-215 corridor in Salt Lake City, Utah. Numerical modeling was utilized to generate a chloride loading function and to determine the diffusion coefficient of each deck. Based on average diffusion coefficients for decks with and without SIPMFs, chloride concentration profiles were computed through time for cover thicknesses of 2.0 in., 2.5 in., and 3.0 in. The results of the work show that the average diffusion coefficient for bridge decks with SIPMFs is approximately twice that of decks without SIPMFs and that, on average, each additional 0.5 in. of cover beyond 2.0 in. allows an extra 2 years for decks with SIPMFs and 5 years for decks without SIPMFs before a surface treatment must be placed to prevent excessive accumulation of chlorides. Although the data generated in this research are based on conditions typical of bridge decks in Utah, they clearly illustrate the effect of cover depth and the presence of SIPMFs. Given these research findings, engineers should carefully determine the appropriate timing for initial applications of surface treatments to concrete bridge decks in consideration of cover depth and the presence of SIPMFs. For maintenance of concrete bridge decks with properties similar to those tested in this study, engineers should follow the guidelines developed in this research to minimize the ingress of chlorides into the decks over time and therefore retard the onset of reinforcement corrosion; altogether separate guidelines may be needed for decks having substantially different properties. Surface treatments should be replaced as needed to ensure continuing protection of the concrete bridge deck against chloride ingress.

The objective of this research was to assess the condition of four decommissioned bridge decks treated with waterproofing membranes and asphalt overlays following the completion of their service lives. Large samples were cut from each of the bridge decks immediately prior to demolition and taken to the Brigham Young University Highway Materials Laboratory, where extensive sampling and testing was performed. Methods used to evaluate the condition of the bridge deck samples included visual inspection, hammer sounding, Schmidt rebound hammer testing, resistivity testing, half-cell potential testing, linear polarization testing, cover depth measurement, and chloride concentration measurement. The samples were removed from four concrete bridge decks along the Interstate 15 corridor in Provo, Utah. One bridge deck was constructed in 1937, two were constructed in 1964, and one was constructed in 1984. Each of the bridge decks was constructed using conventional cast-in-place methods. With the exception of the 1984 bridge deck, which had epoxy-coated rebar, all of the bridge decks were reinforced with black bar. A waterproofing membrane was installed on each of the bridge decks in 1984, meaning each waterproofing membrane had been in service for 26 or 27 years at the time of sampling. With the exception of one of the bridges, which was in good condition after 26 years of service, each of the bridge decks sampled had successfully served for at least 46 years. Aside from asphalt maintenance, no rehabilitation was needed on any of the bridge decks following installation of the waterproofing membranes. Without the application of the waterproofing membranes, the chloride concentrations in the bridge decks likely would have been much higher. Additional exposure to chloride ions from deicing salts would have quickly increased the chloride concentration in the concrete above critical levels, which would have led to significant corrosion and bridge deck deterioration, prematurely. While the application of membranes as a bridge deck maintenance procedure has mostly been replaced by the use of epoxy-based polymer overlays, many bridge decks protected with membrane systems are still in service today. The research findings suggest that application of waterproofing membranes and asphalt overlays in a timely manner, before the accumulation of excessive amounts of chlorides within a deck, can be an effective approach for concrete bridge deck preservation.

The objectives of this research were to 1) compile a synthesis of information about polyester polymer concrete (PPC) from the literature; 2) conduct a scanning tour to observe PPC construction, inspect in-service PPC overlays, and discuss topics related to PPC; 3) revise the existing Utah Department of Transportation (UDOT) PPC specification; 4) document a PPC field demonstration project; and 5) perform laboratory characterization of the material properties of field-mixed PPC. The scope of the research included a scanning tour, field testing, and laboratory experimentation. The objectives of the scanning tour included observation of a PPC overlay placement, inspection of existing overlays, and discussion of selected topics related to PPC. The scanning tour comprised a 3-day visit to California. Items related to material properties, mixture and overlay design, laboratory testing, and construction and field testing were investigated. Several recommendations relevant to Utah bridge deck preservation practice were developed based on the findings and then incorporated into a revised UDOT PPC specification. The objective of the field testing was to evaluate specific aspects of construction, quality assurance, and performance of PPC overlays on concrete bridge decks. The scope of the project included testing of a PPC test section overlay and three PPC bridge deck overlays during and after construction. Hardness tests were performed on the test section placements, and hardness, skid resistance, impact-echo, impedance, and resin content determination tests were performed on each of the bridge deck overlays. The field testing yielded valuable information about PPC overlays. Recommendations regarding hardness testing, skid resistance testing, patching, and surface preparation were developed based on the findings. The objectives of the laboratory experimentation were to characterize several material properties of field-mixed PPC sampled from actual bridge deck overlay placements in Utah and compare them to properties of laboratory-mixed PPC reported in the literature. Laboratory testing was conducted on a typical PPC mixture. Properties that were measured include density, modulus of elasticity, coefficient of thermal expansion, hardness, unconfined compressive strength, splitting tensile strength, rapid chloride permeability, and resin content. Measured properties were consistent with typical ranges cited in the literature.

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