The Experts below are selected from a list of 270 Experts worldwide ranked by ideXlab platform
Donald M. Harrison - One of the best experts on this subject based on the ideXlab platform.
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4 – Epoxy Grout
The Grouting Handbook, 2013Co-Authors: Donald M. HarrisonAbstract:This chapter provides an introduction to epoxies and covers chemistry and the general characteristics of Epoxy Grouts. Temperatures affecting hardening and curing of the Grout and its chemical resistance are covered. Proper mixing of the Epoxy Grout components and the terminology associated with Epoxy Grout is pointed out. The effect of ambient temperature on Epoxy Grout is also covered in this chapter. Lastly, the effect of flow versus clearance is also covered in this chapter.
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1 – The Foundation
The Grouting Handbook, 2013Co-Authors: Donald M. HarrisonAbstract:We start with the initial machinery foundation designs for reciprocating compressor, engine foundations, skid-mounted equipment foundations, and foundations for centrifugal pumps. We make a comparison of the vibration damping capability of steel, concrete, and an Epoxy Grout. The foundation mass to equipment weight ratio for centrifugal pumps and reciprocating equipment is discussed, as well as soil testing for static and dynamic loads. Concrete foundations are discussed as well as the hazards of uncontrolled water addition to the concrete mix at the job site. Concrete add mixtures their types and uses for concrete placement in hot and cold weather, as well as types of Portland cement is covered. At the end, we will outline proper curing of concrete and the acceptable moisture content of concrete before pouring Epoxy Grout as well as guidelines for use of Epoxy Grout on oil-saturated concrete.
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5 – Selecting an Epoxy Grout
The Grouting Handbook, 2013Co-Authors: Donald M. HarrisonAbstract:This chapter provides insight into selecting an Epoxy Grout by providing physical property comparisons of six major Epoxy Grout products. Using recognized ASTM test procedures from ASTM Committee C3, we are able to easily see the variations of physical properties for these products.
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5 selecting an Epoxy Grout
The Grouting Handbook (Second Edition)#R##N#A Step-by-Step Guide, 2013Co-Authors: Donald M. HarrisonAbstract:This chapter provides insight into selecting an Epoxy Grout by providing physical property comparisons of six major Epoxy Grout products. Using recognized ASTM test procedures from ASTM Committee C3, we are able to easily see the variations of physical properties for these products.
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Making Deep Pours with Epoxy Grout
The Grouting Handbook, 2013Co-Authors: Donald M. HarrisonAbstract:Deep, reconstructing pours of Epoxy Grout were first used by the owners of large pipeline compressors during reGrouts. These repairs usually required the removal of 18-24 in. of oil-soaked or damaged concrete. This removed material was replaced with concrete and required between 14-28 days of cure. After the concrete was cured, the surface was chipped to remove laitenance and provide a good surface profile for the Grout to bond. To eliminate long down-times and designed-in failure points, the pipeline industry started using Epoxy Grout with pea gravel filler to form a rapid-set deep pour compound. As an extra benefit, it was found that by using Epoxy Grout as a reconstruction material, machinery vibrations can be reduced significantly. Epoxy Grouts have been used for years in making deep foundation capping repairs and reGrouting heavy equipment due to the cost savings achieved through the reduction in out-of-service time on critical equipment. Recent technology and improved Grouting materials have resulted in a number of Grouting or reGrouting methods that have proved successful in a wide range of applications.
Sharmila Pant - One of the best experts on this subject based on the ideXlab platform.
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Developing Guidelines for Epoxy Grout Pourback Systems for Controlling Thermal/Shrinkage Cracking at Post-Tensioning Anchorages: Full-Scale Testing and Numerical Analysis:
Transportation Research Record, 2018Co-Authors: Irtishad Ahmad, Nakin Suksawang, Khaled Sobhan, John A. Corven, Rick Vallier, Ehssan Amir Sayyafi, Sharmila PantAbstract:Epoxy Grout pourbacks at end anchorages of post-tensioning tendons provide an essential level of corrosion protection. The tendon may fail because of strand corrosion, within a few years of installation, if it is not properly protected with Epoxy Grout pourbacks. Recently, the Florida Department of Transportation (FDOT) found cracking on larger Epoxy Grout pourbacks, possibly as a result of the exothermic nature of the Epoxy Grout curing, causing thermal stresses that increase the potential for pourbacks cracking. Coordinated laboratory and numerical investigations were undertaken to develop best practice guidance for eliminating cracking in Epoxy Grout pourbacks. Potential factors were determined to be the pourback size, shapes, and temperature of the concrete substrate. An Epoxy Grout pourback material was used to construct full-scale pourback systems consisting of rectangular (R-type) and irregular (S-type) pourbacks with volume to surface, V/S ratios of 80, 98, and 113 mm. The full-scale specimens wer...
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developing guidelines for Epoxy Grout pourback systems for controlling thermal shrinkage cracking at post tensioning anchorages full scale testing and numerical analysis
Transportation Research Record, 2018Co-Authors: Irtishad Ahmad, Nakin Suksawang, Khaled Sobhan, John A. Corven, Rick Vallier, Ehssan Amir Sayyafi, Sharmila PantAbstract:Epoxy Grout pourbacks at end anchorages of post-tensioning tendons provide an essential level of corrosion protection. The tendon may fail because of strand corrosion, within a few years of installation, if it is not properly protected with Epoxy Grout pourbacks. Recently, the Florida Department of Transportation (FDOT) found cracking on larger Epoxy Grout pourbacks, possibly as a result of the exothermic nature of the Epoxy Grout curing, causing thermal stresses that increase the potential for pourbacks cracking. Coordinated laboratory and numerical investigations were undertaken to develop best practice guidance for eliminating cracking in Epoxy Grout pourbacks. Potential factors were determined to be the pourback size, shapes, and temperature of the concrete substrate. An Epoxy Grout pourback material was used to construct full-scale pourback systems consisting of rectangular (R-type) and irregular (S-type) pourbacks with volume to surface, V/S ratios of 80, 98, and 113 mm. The full-scale specimens wer...
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Develop Epoxy Grout Pourback Guidance and Test Methods to Eliminate Thermal/Shrinkage Cracking at Post-Tensioning Anchorages: Phase II
2015Co-Authors: Irtishad Ahmad, Nakin Suksawang, Khaled Sobhan, John A. Corven, Ehssan Amir Sayyafi, Sharmila Pant, Fernando MartinezAbstract:This research report contains guidance for eliminating thermal and shrinkage cracking in Epoxy Grout pourbacks used in post-tensioned anchorages. In this study, an experimental investigation of a selected Epoxy Grout pourback material and finite element analysis on the full-scale pourback specimens using the same pourback material were conducted. The study was undertaken to better understand the pourbacks’ failure mechanisms and provide guidelines and methods for eliminating them. Additionally, field investigation of Epoxy Grout pourbacks cracking was made at two bridge sites in Tampa and Miami. Based on a comprehensive literature review, manufacturer and contractor feedbacks, field investigation, and full-scale testing potential factors affecting Epoxy Grout pourback were determined to be the pourback size, shapes (particularly shapes with obtuse corner), ambient condition and concrete substrate’s temperature. The results of the full-scale testing and finite element analysis indicated that the primary cause of pourback failure was due to thermal cracking. The manufacturer-provided peak exothermic temperature did not reflect what was measured in the full-scale specimens as well as in the researchers’ own laboratory test, which were significantly higher. It was found that both the peak exothermic temperature and the maximum thermal stress increased as the volume-to-surface (V/S) ratio increased. It should be noted that the V/S ratios calculated in this report were based on the volume divided by the area of the exposed surfaces (the face of the Epoxy Grout not in contact with the concrete) in ft. The shapes also played a significant role particularly shapes with obtuse corners. The thermal cracks found in the field and full-scale specimens were full-depth cracks that penetrated through the Epoxy Grout. Therefore, it is recommended that these cracks should be immediately sealed. To avoid the thermal cracks, it is highly recommended, based on the findings of this study, that the V/S ratio of the Epoxy Grout be limited to 0.30 ft and 0.35 ft for irregular (S-type) and rectangular (R-type) shaped pourbacks, respectively.
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develop Epoxy Grout pourback guidance and test methods to eliminate thermal shrinkage cracking at post tensioning anchorages phase ii
2015Co-Authors: Irtishad Ahmad, Nakin Suksawang, Khaled Sobhan, John A. Corven, Ehssan Amir Sayyafi, Sharmila Pant, Fernando MartinezAbstract:This research report contains guidance for eliminating thermal and shrinkage cracking in Epoxy Grout pourbacks used in post-tensioned anchorages. In this study, an experimental investigation of a selected Epoxy Grout pourback material and finite element analysis on the full-scale pourback specimens using the same pourback material were conducted. The study was undertaken to better understand the pourbacks’ failure mechanisms and provide guidelines and methods for eliminating them. Additionally, field investigation of Epoxy Grout pourbacks cracking was made at two bridge sites in Tampa and Miami. Based on a comprehensive literature review, manufacturer and contractor feedbacks, field investigation, and full-scale testing potential factors affecting Epoxy Grout pourback were determined to be the pourback size, shapes (particularly shapes with obtuse corner), ambient condition and concrete substrate’s temperature. The results of the full-scale testing and finite element analysis indicated that the primary cause of pourback failure was due to thermal cracking. The manufacturer-provided peak exothermic temperature did not reflect what was measured in the full-scale specimens as well as in the researchers’ own laboratory test, which were significantly higher. It was found that both the peak exothermic temperature and the maximum thermal stress increased as the volume-to-surface (V/S) ratio increased. It should be noted that the V/S ratios calculated in this report were based on the volume divided by the area of the exposed surfaces (the face of the Epoxy Grout not in contact with the concrete) in ft. The shapes also played a significant role particularly shapes with obtuse corners. The thermal cracks found in the field and full-scale specimens were full-depth cracks that penetrated through the Epoxy Grout. Therefore, it is recommended that these cracks should be immediately sealed. To avoid the thermal cracks, it is highly recommended, based on the findings of this study, that the V/S ratio of the Epoxy Grout be limited to 0.30 ft and 0.35 ft for irregular (S-type) and rectangular (R-type) shaped pourbacks, respectively.
Irtishad Ahmad - One of the best experts on this subject based on the ideXlab platform.
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Developing Guidelines for Epoxy Grout Pourback Systems for Controlling Thermal/Shrinkage Cracking at Post-Tensioning Anchorages: Full-Scale Testing and Numerical Analysis:
Transportation Research Record, 2018Co-Authors: Irtishad Ahmad, Nakin Suksawang, Khaled Sobhan, John A. Corven, Rick Vallier, Ehssan Amir Sayyafi, Sharmila PantAbstract:Epoxy Grout pourbacks at end anchorages of post-tensioning tendons provide an essential level of corrosion protection. The tendon may fail because of strand corrosion, within a few years of installation, if it is not properly protected with Epoxy Grout pourbacks. Recently, the Florida Department of Transportation (FDOT) found cracking on larger Epoxy Grout pourbacks, possibly as a result of the exothermic nature of the Epoxy Grout curing, causing thermal stresses that increase the potential for pourbacks cracking. Coordinated laboratory and numerical investigations were undertaken to develop best practice guidance for eliminating cracking in Epoxy Grout pourbacks. Potential factors were determined to be the pourback size, shapes, and temperature of the concrete substrate. An Epoxy Grout pourback material was used to construct full-scale pourback systems consisting of rectangular (R-type) and irregular (S-type) pourbacks with volume to surface, V/S ratios of 80, 98, and 113 mm. The full-scale specimens wer...
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developing guidelines for Epoxy Grout pourback systems for controlling thermal shrinkage cracking at post tensioning anchorages full scale testing and numerical analysis
Transportation Research Record, 2018Co-Authors: Irtishad Ahmad, Nakin Suksawang, Khaled Sobhan, John A. Corven, Rick Vallier, Ehssan Amir Sayyafi, Sharmila PantAbstract:Epoxy Grout pourbacks at end anchorages of post-tensioning tendons provide an essential level of corrosion protection. The tendon may fail because of strand corrosion, within a few years of installation, if it is not properly protected with Epoxy Grout pourbacks. Recently, the Florida Department of Transportation (FDOT) found cracking on larger Epoxy Grout pourbacks, possibly as a result of the exothermic nature of the Epoxy Grout curing, causing thermal stresses that increase the potential for pourbacks cracking. Coordinated laboratory and numerical investigations were undertaken to develop best practice guidance for eliminating cracking in Epoxy Grout pourbacks. Potential factors were determined to be the pourback size, shapes, and temperature of the concrete substrate. An Epoxy Grout pourback material was used to construct full-scale pourback systems consisting of rectangular (R-type) and irregular (S-type) pourbacks with volume to surface, V/S ratios of 80, 98, and 113 mm. The full-scale specimens wer...
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Develop Epoxy Grout Pourback Guidance and Test Methods to Eliminate Thermal/Shrinkage Cracking at Post-Tensioning Anchorages: Phase II
2015Co-Authors: Irtishad Ahmad, Nakin Suksawang, Khaled Sobhan, John A. Corven, Ehssan Amir Sayyafi, Sharmila Pant, Fernando MartinezAbstract:This research report contains guidance for eliminating thermal and shrinkage cracking in Epoxy Grout pourbacks used in post-tensioned anchorages. In this study, an experimental investigation of a selected Epoxy Grout pourback material and finite element analysis on the full-scale pourback specimens using the same pourback material were conducted. The study was undertaken to better understand the pourbacks’ failure mechanisms and provide guidelines and methods for eliminating them. Additionally, field investigation of Epoxy Grout pourbacks cracking was made at two bridge sites in Tampa and Miami. Based on a comprehensive literature review, manufacturer and contractor feedbacks, field investigation, and full-scale testing potential factors affecting Epoxy Grout pourback were determined to be the pourback size, shapes (particularly shapes with obtuse corner), ambient condition and concrete substrate’s temperature. The results of the full-scale testing and finite element analysis indicated that the primary cause of pourback failure was due to thermal cracking. The manufacturer-provided peak exothermic temperature did not reflect what was measured in the full-scale specimens as well as in the researchers’ own laboratory test, which were significantly higher. It was found that both the peak exothermic temperature and the maximum thermal stress increased as the volume-to-surface (V/S) ratio increased. It should be noted that the V/S ratios calculated in this report were based on the volume divided by the area of the exposed surfaces (the face of the Epoxy Grout not in contact with the concrete) in ft. The shapes also played a significant role particularly shapes with obtuse corners. The thermal cracks found in the field and full-scale specimens were full-depth cracks that penetrated through the Epoxy Grout. Therefore, it is recommended that these cracks should be immediately sealed. To avoid the thermal cracks, it is highly recommended, based on the findings of this study, that the V/S ratio of the Epoxy Grout be limited to 0.30 ft and 0.35 ft for irregular (S-type) and rectangular (R-type) shaped pourbacks, respectively.
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develop Epoxy Grout pourback guidance and test methods to eliminate thermal shrinkage cracking at post tensioning anchorages phase ii
2015Co-Authors: Irtishad Ahmad, Nakin Suksawang, Khaled Sobhan, John A. Corven, Ehssan Amir Sayyafi, Sharmila Pant, Fernando MartinezAbstract:This research report contains guidance for eliminating thermal and shrinkage cracking in Epoxy Grout pourbacks used in post-tensioned anchorages. In this study, an experimental investigation of a selected Epoxy Grout pourback material and finite element analysis on the full-scale pourback specimens using the same pourback material were conducted. The study was undertaken to better understand the pourbacks’ failure mechanisms and provide guidelines and methods for eliminating them. Additionally, field investigation of Epoxy Grout pourbacks cracking was made at two bridge sites in Tampa and Miami. Based on a comprehensive literature review, manufacturer and contractor feedbacks, field investigation, and full-scale testing potential factors affecting Epoxy Grout pourback were determined to be the pourback size, shapes (particularly shapes with obtuse corner), ambient condition and concrete substrate’s temperature. The results of the full-scale testing and finite element analysis indicated that the primary cause of pourback failure was due to thermal cracking. The manufacturer-provided peak exothermic temperature did not reflect what was measured in the full-scale specimens as well as in the researchers’ own laboratory test, which were significantly higher. It was found that both the peak exothermic temperature and the maximum thermal stress increased as the volume-to-surface (V/S) ratio increased. It should be noted that the V/S ratios calculated in this report were based on the volume divided by the area of the exposed surfaces (the face of the Epoxy Grout not in contact with the concrete) in ft. The shapes also played a significant role particularly shapes with obtuse corners. The thermal cracks found in the field and full-scale specimens were full-depth cracks that penetrated through the Epoxy Grout. Therefore, it is recommended that these cracks should be immediately sealed. To avoid the thermal cracks, it is highly recommended, based on the findings of this study, that the V/S ratio of the Epoxy Grout be limited to 0.30 ft and 0.35 ft for irregular (S-type) and rectangular (R-type) shaped pourbacks, respectively.
Khaled Sobhan - One of the best experts on this subject based on the ideXlab platform.
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Developing Guidelines for Epoxy Grout Pourback Systems for Controlling Thermal/Shrinkage Cracking at Post-Tensioning Anchorages: Full-Scale Testing and Numerical Analysis:
Transportation Research Record, 2018Co-Authors: Irtishad Ahmad, Nakin Suksawang, Khaled Sobhan, John A. Corven, Rick Vallier, Ehssan Amir Sayyafi, Sharmila PantAbstract:Epoxy Grout pourbacks at end anchorages of post-tensioning tendons provide an essential level of corrosion protection. The tendon may fail because of strand corrosion, within a few years of installation, if it is not properly protected with Epoxy Grout pourbacks. Recently, the Florida Department of Transportation (FDOT) found cracking on larger Epoxy Grout pourbacks, possibly as a result of the exothermic nature of the Epoxy Grout curing, causing thermal stresses that increase the potential for pourbacks cracking. Coordinated laboratory and numerical investigations were undertaken to develop best practice guidance for eliminating cracking in Epoxy Grout pourbacks. Potential factors were determined to be the pourback size, shapes, and temperature of the concrete substrate. An Epoxy Grout pourback material was used to construct full-scale pourback systems consisting of rectangular (R-type) and irregular (S-type) pourbacks with volume to surface, V/S ratios of 80, 98, and 113 mm. The full-scale specimens wer...
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developing guidelines for Epoxy Grout pourback systems for controlling thermal shrinkage cracking at post tensioning anchorages full scale testing and numerical analysis
Transportation Research Record, 2018Co-Authors: Irtishad Ahmad, Nakin Suksawang, Khaled Sobhan, John A. Corven, Rick Vallier, Ehssan Amir Sayyafi, Sharmila PantAbstract:Epoxy Grout pourbacks at end anchorages of post-tensioning tendons provide an essential level of corrosion protection. The tendon may fail because of strand corrosion, within a few years of installation, if it is not properly protected with Epoxy Grout pourbacks. Recently, the Florida Department of Transportation (FDOT) found cracking on larger Epoxy Grout pourbacks, possibly as a result of the exothermic nature of the Epoxy Grout curing, causing thermal stresses that increase the potential for pourbacks cracking. Coordinated laboratory and numerical investigations were undertaken to develop best practice guidance for eliminating cracking in Epoxy Grout pourbacks. Potential factors were determined to be the pourback size, shapes, and temperature of the concrete substrate. An Epoxy Grout pourback material was used to construct full-scale pourback systems consisting of rectangular (R-type) and irregular (S-type) pourbacks with volume to surface, V/S ratios of 80, 98, and 113 mm. The full-scale specimens wer...
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Develop Epoxy Grout Pourback Guidance and Test Methods to Eliminate Thermal/Shrinkage Cracking at Post-Tensioning Anchorages: Phase II
2015Co-Authors: Irtishad Ahmad, Nakin Suksawang, Khaled Sobhan, John A. Corven, Ehssan Amir Sayyafi, Sharmila Pant, Fernando MartinezAbstract:This research report contains guidance for eliminating thermal and shrinkage cracking in Epoxy Grout pourbacks used in post-tensioned anchorages. In this study, an experimental investigation of a selected Epoxy Grout pourback material and finite element analysis on the full-scale pourback specimens using the same pourback material were conducted. The study was undertaken to better understand the pourbacks’ failure mechanisms and provide guidelines and methods for eliminating them. Additionally, field investigation of Epoxy Grout pourbacks cracking was made at two bridge sites in Tampa and Miami. Based on a comprehensive literature review, manufacturer and contractor feedbacks, field investigation, and full-scale testing potential factors affecting Epoxy Grout pourback were determined to be the pourback size, shapes (particularly shapes with obtuse corner), ambient condition and concrete substrate’s temperature. The results of the full-scale testing and finite element analysis indicated that the primary cause of pourback failure was due to thermal cracking. The manufacturer-provided peak exothermic temperature did not reflect what was measured in the full-scale specimens as well as in the researchers’ own laboratory test, which were significantly higher. It was found that both the peak exothermic temperature and the maximum thermal stress increased as the volume-to-surface (V/S) ratio increased. It should be noted that the V/S ratios calculated in this report were based on the volume divided by the area of the exposed surfaces (the face of the Epoxy Grout not in contact with the concrete) in ft. The shapes also played a significant role particularly shapes with obtuse corners. The thermal cracks found in the field and full-scale specimens were full-depth cracks that penetrated through the Epoxy Grout. Therefore, it is recommended that these cracks should be immediately sealed. To avoid the thermal cracks, it is highly recommended, based on the findings of this study, that the V/S ratio of the Epoxy Grout be limited to 0.30 ft and 0.35 ft for irregular (S-type) and rectangular (R-type) shaped pourbacks, respectively.
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develop Epoxy Grout pourback guidance and test methods to eliminate thermal shrinkage cracking at post tensioning anchorages phase ii
2015Co-Authors: Irtishad Ahmad, Nakin Suksawang, Khaled Sobhan, John A. Corven, Ehssan Amir Sayyafi, Sharmila Pant, Fernando MartinezAbstract:This research report contains guidance for eliminating thermal and shrinkage cracking in Epoxy Grout pourbacks used in post-tensioned anchorages. In this study, an experimental investigation of a selected Epoxy Grout pourback material and finite element analysis on the full-scale pourback specimens using the same pourback material were conducted. The study was undertaken to better understand the pourbacks’ failure mechanisms and provide guidelines and methods for eliminating them. Additionally, field investigation of Epoxy Grout pourbacks cracking was made at two bridge sites in Tampa and Miami. Based on a comprehensive literature review, manufacturer and contractor feedbacks, field investigation, and full-scale testing potential factors affecting Epoxy Grout pourback were determined to be the pourback size, shapes (particularly shapes with obtuse corner), ambient condition and concrete substrate’s temperature. The results of the full-scale testing and finite element analysis indicated that the primary cause of pourback failure was due to thermal cracking. The manufacturer-provided peak exothermic temperature did not reflect what was measured in the full-scale specimens as well as in the researchers’ own laboratory test, which were significantly higher. It was found that both the peak exothermic temperature and the maximum thermal stress increased as the volume-to-surface (V/S) ratio increased. It should be noted that the V/S ratios calculated in this report were based on the volume divided by the area of the exposed surfaces (the face of the Epoxy Grout not in contact with the concrete) in ft. The shapes also played a significant role particularly shapes with obtuse corners. The thermal cracks found in the field and full-scale specimens were full-depth cracks that penetrated through the Epoxy Grout. Therefore, it is recommended that these cracks should be immediately sealed. To avoid the thermal cracks, it is highly recommended, based on the findings of this study, that the V/S ratio of the Epoxy Grout be limited to 0.30 ft and 0.35 ft for irregular (S-type) and rectangular (R-type) shaped pourbacks, respectively.
Nakin Suksawang - One of the best experts on this subject based on the ideXlab platform.
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Developing Guidelines for Epoxy Grout Pourback Systems for Controlling Thermal/Shrinkage Cracking at Post-Tensioning Anchorages: Full-Scale Testing and Numerical Analysis:
Transportation Research Record, 2018Co-Authors: Irtishad Ahmad, Nakin Suksawang, Khaled Sobhan, John A. Corven, Rick Vallier, Ehssan Amir Sayyafi, Sharmila PantAbstract:Epoxy Grout pourbacks at end anchorages of post-tensioning tendons provide an essential level of corrosion protection. The tendon may fail because of strand corrosion, within a few years of installation, if it is not properly protected with Epoxy Grout pourbacks. Recently, the Florida Department of Transportation (FDOT) found cracking on larger Epoxy Grout pourbacks, possibly as a result of the exothermic nature of the Epoxy Grout curing, causing thermal stresses that increase the potential for pourbacks cracking. Coordinated laboratory and numerical investigations were undertaken to develop best practice guidance for eliminating cracking in Epoxy Grout pourbacks. Potential factors were determined to be the pourback size, shapes, and temperature of the concrete substrate. An Epoxy Grout pourback material was used to construct full-scale pourback systems consisting of rectangular (R-type) and irregular (S-type) pourbacks with volume to surface, V/S ratios of 80, 98, and 113 mm. The full-scale specimens wer...
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developing guidelines for Epoxy Grout pourback systems for controlling thermal shrinkage cracking at post tensioning anchorages full scale testing and numerical analysis
Transportation Research Record, 2018Co-Authors: Irtishad Ahmad, Nakin Suksawang, Khaled Sobhan, John A. Corven, Rick Vallier, Ehssan Amir Sayyafi, Sharmila PantAbstract:Epoxy Grout pourbacks at end anchorages of post-tensioning tendons provide an essential level of corrosion protection. The tendon may fail because of strand corrosion, within a few years of installation, if it is not properly protected with Epoxy Grout pourbacks. Recently, the Florida Department of Transportation (FDOT) found cracking on larger Epoxy Grout pourbacks, possibly as a result of the exothermic nature of the Epoxy Grout curing, causing thermal stresses that increase the potential for pourbacks cracking. Coordinated laboratory and numerical investigations were undertaken to develop best practice guidance for eliminating cracking in Epoxy Grout pourbacks. Potential factors were determined to be the pourback size, shapes, and temperature of the concrete substrate. An Epoxy Grout pourback material was used to construct full-scale pourback systems consisting of rectangular (R-type) and irregular (S-type) pourbacks with volume to surface, V/S ratios of 80, 98, and 113 mm. The full-scale specimens wer...
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Develop Epoxy Grout Pourback Guidance and Test Methods to Eliminate Thermal/Shrinkage Cracking at Post-Tensioning Anchorages: Phase II
2015Co-Authors: Irtishad Ahmad, Nakin Suksawang, Khaled Sobhan, John A. Corven, Ehssan Amir Sayyafi, Sharmila Pant, Fernando MartinezAbstract:This research report contains guidance for eliminating thermal and shrinkage cracking in Epoxy Grout pourbacks used in post-tensioned anchorages. In this study, an experimental investigation of a selected Epoxy Grout pourback material and finite element analysis on the full-scale pourback specimens using the same pourback material were conducted. The study was undertaken to better understand the pourbacks’ failure mechanisms and provide guidelines and methods for eliminating them. Additionally, field investigation of Epoxy Grout pourbacks cracking was made at two bridge sites in Tampa and Miami. Based on a comprehensive literature review, manufacturer and contractor feedbacks, field investigation, and full-scale testing potential factors affecting Epoxy Grout pourback were determined to be the pourback size, shapes (particularly shapes with obtuse corner), ambient condition and concrete substrate’s temperature. The results of the full-scale testing and finite element analysis indicated that the primary cause of pourback failure was due to thermal cracking. The manufacturer-provided peak exothermic temperature did not reflect what was measured in the full-scale specimens as well as in the researchers’ own laboratory test, which were significantly higher. It was found that both the peak exothermic temperature and the maximum thermal stress increased as the volume-to-surface (V/S) ratio increased. It should be noted that the V/S ratios calculated in this report were based on the volume divided by the area of the exposed surfaces (the face of the Epoxy Grout not in contact with the concrete) in ft. The shapes also played a significant role particularly shapes with obtuse corners. The thermal cracks found in the field and full-scale specimens were full-depth cracks that penetrated through the Epoxy Grout. Therefore, it is recommended that these cracks should be immediately sealed. To avoid the thermal cracks, it is highly recommended, based on the findings of this study, that the V/S ratio of the Epoxy Grout be limited to 0.30 ft and 0.35 ft for irregular (S-type) and rectangular (R-type) shaped pourbacks, respectively.
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develop Epoxy Grout pourback guidance and test methods to eliminate thermal shrinkage cracking at post tensioning anchorages phase ii
2015Co-Authors: Irtishad Ahmad, Nakin Suksawang, Khaled Sobhan, John A. Corven, Ehssan Amir Sayyafi, Sharmila Pant, Fernando MartinezAbstract:This research report contains guidance for eliminating thermal and shrinkage cracking in Epoxy Grout pourbacks used in post-tensioned anchorages. In this study, an experimental investigation of a selected Epoxy Grout pourback material and finite element analysis on the full-scale pourback specimens using the same pourback material were conducted. The study was undertaken to better understand the pourbacks’ failure mechanisms and provide guidelines and methods for eliminating them. Additionally, field investigation of Epoxy Grout pourbacks cracking was made at two bridge sites in Tampa and Miami. Based on a comprehensive literature review, manufacturer and contractor feedbacks, field investigation, and full-scale testing potential factors affecting Epoxy Grout pourback were determined to be the pourback size, shapes (particularly shapes with obtuse corner), ambient condition and concrete substrate’s temperature. The results of the full-scale testing and finite element analysis indicated that the primary cause of pourback failure was due to thermal cracking. The manufacturer-provided peak exothermic temperature did not reflect what was measured in the full-scale specimens as well as in the researchers’ own laboratory test, which were significantly higher. It was found that both the peak exothermic temperature and the maximum thermal stress increased as the volume-to-surface (V/S) ratio increased. It should be noted that the V/S ratios calculated in this report were based on the volume divided by the area of the exposed surfaces (the face of the Epoxy Grout not in contact with the concrete) in ft. The shapes also played a significant role particularly shapes with obtuse corners. The thermal cracks found in the field and full-scale specimens were full-depth cracks that penetrated through the Epoxy Grout. Therefore, it is recommended that these cracks should be immediately sealed. To avoid the thermal cracks, it is highly recommended, based on the findings of this study, that the V/S ratio of the Epoxy Grout be limited to 0.30 ft and 0.35 ft for irregular (S-type) and rectangular (R-type) shaped pourbacks, respectively.