The Experts below are selected from a list of 219 Experts worldwide ranked by ideXlab platform
Neil Lennart Anderson - One of the best experts on this subject based on the ideXlab platform.
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An Attempt to Describe a Relationship between Concrete Deterioration Quantities and Bridge Deck Condition Assessment Techniques
Journal of Applied Geophysics, 2017Co-Authors: Aleksandra V. Varnavina, Lesley Sneed, Aleksey K. Khamzin, Evgeniy V. Torgashov, Neil Lennart AndersonAbstract:Abstract This paper presents a study of the performance of four techniques – visual inspection, Ground Penetrating Radar (GPR), Ultrasonic Surface Wave (USW), and core control – that were used to assess condition of a Concrete bridge deck. The bridge deck was then rehabilitated using hydrodemolition, and the Concrete removed during hydrodemolition was assumed to be deteriorated. LiDAR measurements of Concrete depth Removal collected after hydrodemolition were used as ground truth. Comparisons of bridge deck condition assessment data and LiDAR Concrete Removal measurements were performed in this study. The comparisons attempt to find and describe a possible relationship between bridge deck assessment techniques and quantities of Concrete deterioration.
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Concrete bridge deck assessment: Relationship between GPR data and Concrete Removal depth measurements collected after hydrodemolition
Construction and Building Materials, 2015Co-Authors: Aleksandra V. Varnavina, Lesley Sneed, Aleksey K. Khamzin, Evgeniy V. Torgashov, Neil Lennart Anderson, Norbert H. Maerz, Kenneth J. BoykoAbstract:Abstract A ground-coupled ground penetrating radar (GPR) system was used to assess the condition of two reinforced Concrete bridge decks. After each GPR assessment was completed, the bridge deck was rehabilitated using a hydrodemolition process to remove deteriorated Concrete from upper surface of the deck. LiDAR technology was used to create maps depicting the deck surface before and after the Concrete Removal. The objective of this work was to corroborate the GPR condition assessments by comparing the spatial distribution of the GPR and LiDAR mappings. This work illustrates that GPR data have the potential to predict Concrete repair estimates.
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Nondestructive Evaluation of MoDOT Bridge Decks – Pilot Study
2014Co-Authors: Lesley Sneed, Neil Lennart Anderson, Evgeniy V. TorgashovAbstract:This research has examined the use of nondestructive techniques for Concrete bridge deck condition assessments. The primary nondestructive testing/evaluation (NDT/NDE) technique utilized in this research was ground-coupled ground penetrating radar (GPR). The objectives of this research were to examine the utility of the nondestructive techniques in evaluating the condition of Missouri Department of Transportation (MoDOT) bridge decks to enable faster, better, and more cost-effective bridge deck assessments, and to determine the accuracy of the information provided. Eleven bridge decks were investigated using detailed visual inspections, GPR, portable seismic property analyzer (PSPA), core extraction, and chloride ion concentration measurements. The cores underwent a detailed visual evaluation and testing to determine the volume of permeable pore space. Data sets were compared to determine correlations between the results. Three of the bridge decks investigated underwent rehabilitation by hydrodemolition after the initial investigation, and Concrete material Removal was surveyed using lidar to evaluate the NDE estimations. Good correlation was observed qualitatively. Areas of the decks where the GPR interpretations indicated evidence of extensive deterioration generally corresponded to areas with greater Concrete material Removal depths after hydrodemolition, and areas where the GPR interpretations indicated no evidence of deterioration generally corresponded to areas with minimal Concrete Removal. Findings suggest that the correlation between the GPR interpretations and Concrete Removal depths can be improved quantitatively by adjusting the GPR threshold values used in the interpretation, although the major challenge will be to understand how to determine the threshold values without having the benefit of the control data. Finally, recommended parameters are provided for ground-coupled GPR data acquisition, processing, and interpretation.
Aleksandra V. Varnavina - One of the best experts on this subject based on the ideXlab platform.
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An Attempt to Describe a Relationship between Concrete Deterioration Quantities and Bridge Deck Condition Assessment Techniques
Journal of Applied Geophysics, 2017Co-Authors: Aleksandra V. Varnavina, Lesley Sneed, Aleksey K. Khamzin, Evgeniy V. Torgashov, Neil Lennart AndersonAbstract:Abstract This paper presents a study of the performance of four techniques – visual inspection, Ground Penetrating Radar (GPR), Ultrasonic Surface Wave (USW), and core control – that were used to assess condition of a Concrete bridge deck. The bridge deck was then rehabilitated using hydrodemolition, and the Concrete removed during hydrodemolition was assumed to be deteriorated. LiDAR measurements of Concrete depth Removal collected after hydrodemolition were used as ground truth. Comparisons of bridge deck condition assessment data and LiDAR Concrete Removal measurements were performed in this study. The comparisons attempt to find and describe a possible relationship between bridge deck assessment techniques and quantities of Concrete deterioration.
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Concrete bridge deck assessment: Relationship between GPR data and Concrete Removal depth measurements collected after hydrodemolition
Construction and Building Materials, 2015Co-Authors: Aleksandra V. Varnavina, Lesley Sneed, Aleksey K. Khamzin, Evgeniy V. Torgashov, Neil Lennart Anderson, Norbert H. Maerz, Kenneth J. BoykoAbstract:Abstract A ground-coupled ground penetrating radar (GPR) system was used to assess the condition of two reinforced Concrete bridge decks. After each GPR assessment was completed, the bridge deck was rehabilitated using a hydrodemolition process to remove deteriorated Concrete from upper surface of the deck. LiDAR technology was used to create maps depicting the deck surface before and after the Concrete Removal. The objective of this work was to corroborate the GPR condition assessments by comparing the spatial distribution of the GPR and LiDAR mappings. This work illustrates that GPR data have the potential to predict Concrete repair estimates.
Eric C Lohrey - One of the best experts on this subject based on the ideXlab platform.
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Use of hydrodemolition to remove deteriorated Concrete from bridge decks
Transportation Research Record, 1995Co-Authors: Eric C LohreyAbstract:Hydrodemolition is a relatively new method of removing select portions of a hardened Concrete structure. By using the erosive power of high-velocity water streams, hydrodemolition equipment breaks up Concrete by disintegrating the cement matrix between aggregates. The demolishing effect can be tightly controlled to a desired level of Removal, ranging from light scarification of the surface to deep penetration of the structural element. The use of the hydrodemolition process has several advantages over conventional Concrete Removal methods, such as jackhammering. These advantages include a reduction in new damage caused by the Removal process; automation, which produces a very consistent level of Removal energy over large areas; the ability to seek out and remove weak or deteriorated locations at various depths; and a rough, high-quality bonding surface for repair materials. These characteristics are favorable for construction projects that involve rehabilitation of corrosion-damaged reinforced Concrete structures, particularly bridge decks. Details of the hydrodemolition process, equipment operating parameters, and incidental requirements are provided. In addition, appropriate structural conditions that favor the use of hydrodemolition and various methods of specifying work items related to bridge deck rehabilitation are described. The need for comprehensive field evaluations of Concrete structures before rehabilitation strategies are developed was found during the course of the work.
Nele De Belie - One of the best experts on this subject based on the ideXlab platform.
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bond strength between Concrete and repair mortar and its relation with Concrete Removal techniques and substrate composition
Construction and Building Materials, 2020Co-Authors: Mohammad Ali Yazdi, Elien Dejager, Mats Debraekeleer, Elke Gruyaert, Kim Van Tittelboom, Nele De BelieAbstract:Abstract This study investigates how Concrete Removal techniques affect substrates of different compositions, and as a result, the bonding with repair mortar. To this end, substrate surfaces of different Concrete compositions, micro-Concrete (MC), gravel Concrete (GC) and crushed stone Concrete (CC), were treated by using three commonly used Removal techniques; hydrodemolition/water-jetting (WJ), jack-hammering (JH) and grit blasting (GB). Automated laser measurements (ALM) and the volumetric sand patch technique were employed to determine the surface roughness of the substrates. The effect of the substrates parameters such as aggregate size and uniformity on the bonding and failure modes was investigated. Uniformity of the substrates was evaluated by porosity measurements. According to the results, bond strength, surface tensile strength, failure modes and surface roughness were dependent on the aggregate size, aggregate shape and uniformity of mixture. The largest aggregate size and highest porosity along with the highest microcrack density and roughness belonged to CC mixtures. A high correlation was observed between the measured water transport and bond strength of samples. Micro-cracking and a weak interfacial transition zone (ITZ) seem to be the detrimental factors influencing the bond strength of samples treated with JH and WJ, respectively. The influence of WJ on the bond strength was dependent on the mix composition parameters such as aggregate size.
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How Concrete Removal techniques affect the bonding between Concrete and repair mortar
MATEC Web of Conferences, 2019Co-Authors: Mohammad Ali Yazdi, Elien Dejager, Mats Debraekeleer, Elke Gruyaert, Kim Van Tittelboom, Nele De BelieAbstract:Many bonding failures between the substrate and repair mortar are attributed to too aggressive Removal of the contaminated Concrete and incorrect use of repair materials. To this end, in this study the effect of Concrete Removal techniques on substrates of different compositions and, as a result, on the bonding with repair mortar has been investigated. Substrate surfaces of different Concrete compositions, micro-Concrete (MC) and crushed stone Concrete (CC), were treated by using three commonly used techniques: grit blasting (GB), jack-hammering (JH), and hydrodemolition/water-jetting (WJ). Automated Laser Measurements (ALM), sand patch tests and surface tensile strength measurements were applied to characterize the substrate surface. According to the results, the co-lateral effects of Removal techniques such as WJ are dependent on the Concrete mix composition. Moreover, WJ- and JH- treated samples achieved a lower surface tensile strength and bond strength compared to GB-treated slabs.
R L Roberts - One of the best experts on this subject based on the ideXlab platform.
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EVALUATION OF GPR BRIDGE DECK SURVEY RESULTS USED FOR DELINEATION OF Removal/MAINTENANCE QUANTITY BOUNDARIES ON ASPHALT-OVERLAID, REINFORCED Concrete DECK
2000Co-Authors: F A Romero, G E Roberts, R L RobertsAbstract:Ground Penetrating Radar (GPR) was used to delineate deteriorated sections in a bridge deck located in New Hampshire. Recent developments in GPR technology provided high resolution images of the bridge deck structure that were used to create contour maps detailing different levels of deterioration. Because this was the first time this particular GPR method was used as a maintenance-level tool, and the decision database associated with the emerging technology was small, the appropriate contour level to use for Concrete replacement was difficult to assess at the time by either Geophysical Survey Systems, Inc. (GSSI) or the New Hampshire Department of Transportation (NHDOT). The GPR interpretation suggested a contour level on the map that yielded a total Concrete replacement area that exceeded the threshold for a cut-and-patch approach to rehabilitation. NHDOT decided to rehabilitate the deck within a tighter contour level, resulting in less initial Concrete Removal. This decision was based on a number of factors, including available project funding and the required life expectancy of the structure. If the initial rehabilitation-threshold contour level had been used instead, the entire deck surface would have been removed to at least the upper rebar level, then topped with new Concrete and an asphalt overlay. As the asphalt was stripped in preparation for final overlay, it became evident that a significant amount of deterioration on the deck remained. Consequently, additional repair was required. A comparison/contrast between (a) the actual maintenance costs incurred on the project and (b) the originally estimated costs for completing the project could therefore be shown. This advanced GPR technique has been used effectively and accurately to guide the decisions for Removal of deteriorated Concrete prior to repair. With further refinements in methodology already addressed through discussions between NHDOT and GSSI, its judicious use can save a significant amount of money when decisions between various maintenance regimes must be made.
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evaluation of gpr bridge deck survey results used for delineation of Removal maintenance quantity boundaries on asphalt overlaid reinforced Concrete deck
Structural Materials Technology IV - An NDT ConferenceNew York State Department of Transportation; New Jersey Department of Transportation; and Federa, 2000Co-Authors: F A Romero, G E Roberts, R L RobertsAbstract:Ground Penetrating Radar (GPR) was used to delineate deteriorated sections in a bridge deck located in New Hampshire. Recent developments in GPR technology provided high resolution images of the bridge deck structure that were used to create contour maps detailing different levels of deterioration. Because this was the first time this particular GPR method was used as a maintenance-level tool, and the decision database associated with the emerging technology was small, the appropriate contour level to use for Concrete replacement was difficult to assess at the time by either Geophysical Survey Systems, Inc. (GSSI) or the New Hampshire Department of Transportation (NHDOT). The GPR interpretation suggested a contour level on the map that yielded a total Concrete replacement area that exceeded the threshold for a cut-and-patch approach to rehabilitation. NHDOT decided to rehabilitate the deck within a tighter contour level, resulting in less initial Concrete Removal. This decision was based on a number of factors, including available project funding and the required life expectancy of the structure. If the initial rehabilitation-threshold contour level had been used instead, the entire deck surface would have been removed to at least the upper rebar level, then topped with new Concrete and an asphalt overlay. As the asphalt was stripped in preparation for final overlay, it became evident that a significant amount of deterioration on the deck remained. Consequently, additional repair was required. A comparison/contrast between (a) the actual maintenance costs incurred on the project and (b) the originally estimated costs for completing the project could therefore be shown. This advanced GPR technique has been used effectively and accurately to guide the decisions for Removal of deteriorated Concrete prior to repair. With further refinements in methodology already addressed through discussions between NHDOT and GSSI, its judicious use can save a significant amount of money when decisions between various maintenance regimes must be made.