The traffic volume and the amount of heavy traffic on German motorways increased steadily. To guarantee mobility and reduce the national economic costs, road construction with maximum service life, minimum maintenance and minimum traffic restrictions for maintenance are needed. Continuously reinforced concrete pavement (CRCP) are extremely durable in terms of use and maintenance. CRCP offer lower thickness, no transversal joints and the possibility to improve skid resistance and reduction of noise emissions through a thin asphalt surface. The performance of CRCP is influenced by a number of specific characteristics such as the thickness and the quality of the concrete, the longitudinal and transversal reinforcement, the base layer and the environmental conditions. These aspects influence the crack pattern, crack distance and crack widths. In Germany CRCP is in the stage of field testing. From 1997 to today, a total of 8 sections with many variations have been constructed. A detailed comparative study of these sections has been lacking. As part of a research project, the RWTH University and the German Federal Highway Research Institute (BASt) are investigating these sections in CRCP with and without an asphalt surface in Germany and compare it to the Belgium standard constructions. Three CRCP sections were selected and evaluated throughout Germany. The aim is to evaluate the different designs in the sections in terms of their behavior, to quantify achievable service life, necessary maintenance and availability. From this, a preferred variant of the construction is designed and implemented on a motorway in Germany as part of a trial site.
{"title":"A comparative study of crack behavior of continuously reinforced concrete pavements (CRCP) on three sections in Germany","authors":"M. Moharekpour, S. Hoeller, M. Oeser","doi":"10.33593/4pr5xno7","DOIUrl":"https://doi.org/10.33593/4pr5xno7","url":null,"abstract":"The traffic volume and the amount of heavy traffic on German motorways increased steadily. To guarantee mobility and reduce the national economic costs, road construction with maximum service life, minimum maintenance and minimum traffic restrictions for maintenance are needed. Continuously reinforced concrete pavement (CRCP) are extremely durable in terms of use and maintenance. CRCP offer lower thickness, no transversal joints and the possibility to improve skid resistance and reduction of noise emissions through a thin asphalt surface. The performance of CRCP is influenced by a number of specific characteristics such as the thickness and the quality of the concrete, the longitudinal and transversal reinforcement, the base layer and the environmental conditions. These aspects influence the crack pattern, crack distance and crack widths. In Germany CRCP is in the stage of field testing. From 1997 to today, a total of 8 sections with many variations have been constructed. A detailed comparative study of these sections has been lacking. As part of a research project, the RWTH University and the German Federal Highway Research Institute (BASt) are investigating these sections in CRCP with and without an asphalt surface in Germany and compare it to the Belgium standard constructions. Three CRCP sections were selected and evaluated throughout Germany. The aim is to evaluate the different designs in the sections in terms of their behavior, to quantify achievable service life, necessary maintenance and availability. From this, a preferred variant of the construction is designed and implemented on a motorway in Germany as part of a trial site.","PeriodicalId":265129,"journal":{"name":"Proceedings of the 12th International Conference on Concrete Pavements","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130178194","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Local calibration of the punchout model in the Pavement ME software is a vital step in achieving performance predictability for the design of Continuously Reinforced Concrete (CRC) pavement. In Oklahoma, there was only limited performance data available in the General Pavement Studies (GPS) database for CRC pavement. This set of circumstances required a different approach as to the type of data used for calibration. The type of data originally utilized in NCHRP 1-37A essentially represented visually evident damage that is clearly observable at the surface of the pavement structure. Non-observable damage however is actually of greater value as a source of calibration data since it represents the deteriorative conditions that lead to the visual manifestation of the damage process. Since visually validated distress is the end result of the distress cycle the traffic level associated with it is often subject to a considerable amount of error. In this regard, non-observable data such as erosion damage is shown to be a good indicator of and a substitute for actual punchout data since it represents the deterioration of the slab subbase interface that has be found to closely aligned with the punchout process. The amount of erosion is evaluated based on FWD data and is shown it to be a reliable way to determine the calibration coefficients for the punchout model. This paper proposes an approach for calibrating local coefficients for CRC pavements based on non-observable performance data. The main process of this methodology requires estimating erosion percentage damage using Falling Weight Deflectometer data (FWD), determining the percentage of punchout from the Long-Term Performance Program (LTPP) records, and establishing the relationship between both components to estimate the existing punchout distresses. This relationship can be used to calculate the actual damage including erosion damage and to calibrate the local coefficients used in the pavement ME punchout model. This methodology was carried out on one section from Oklahoma and one section from Texas in order to validate its applicability and conclude on the pavement ME punchout model and its ability to predict punchout distress in the field.
{"title":"Developing New Approach to CRC Pavement Punchout Model Calibration","authors":"Issa M. Issa, D. Zollinger","doi":"10.33593/ixt4104e","DOIUrl":"https://doi.org/10.33593/ixt4104e","url":null,"abstract":"Local calibration of the punchout model in the Pavement ME software is a vital step in achieving performance predictability for the design of Continuously Reinforced Concrete (CRC) pavement. In Oklahoma, there was only limited performance data available in the General Pavement Studies (GPS) database for CRC pavement. This set of circumstances required a different approach as to the type of data used for calibration. The type of data originally utilized in NCHRP 1-37A essentially represented visually evident damage that is clearly observable at the surface of the pavement structure. Non-observable damage however is actually of greater value as a source of calibration data since it represents the deteriorative conditions that lead to the visual manifestation of the damage process. Since visually validated distress is the end result of the distress cycle the traffic level associated with it is often subject to a considerable amount of error. In this regard, non-observable data such as erosion damage is shown to be a good indicator of and a substitute for actual punchout data since it represents the deterioration of the slab subbase interface that has be found to closely aligned with the punchout process. The amount of erosion is evaluated based on FWD data and is shown it to be a reliable way to determine the calibration coefficients for the punchout model. This paper proposes an approach for calibrating local coefficients for CRC pavements based on non-observable performance data. The main process of this methodology requires estimating erosion percentage damage using Falling Weight Deflectometer data (FWD), determining the percentage of punchout from the Long-Term Performance Program (LTPP) records, and establishing the relationship between both components to estimate the existing punchout distresses. This relationship can be used to calculate the actual damage including erosion damage and to calibrate the local coefficients used in the pavement ME punchout model. This methodology was carried out on one section from Oklahoma and one section from Texas in order to validate its applicability and conclude on the pavement ME punchout model and its ability to predict punchout distress in the field.","PeriodicalId":265129,"journal":{"name":"Proceedings of the 12th International Conference on Concrete Pavements","volume":"7 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129465019","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A 36-lane-mile (60 lane-km) international roadway was rehabilitated in the United States of America (USA) during 2018 by the New Mexico Department of Transportation (NMDOT) to provide uninterrupted long-life pavement performance for commercial users of the roadway. The southern border of the USA with the country of Mexico marks the starting point of New Mexico State Road 136 (NM 136), a four-lane divided roadway that carries heavily-loaded trucks associated with the United States–Mexico–Canada Agreement (USMCA), formerly the North American Free Trade Agreement (NAFTA). Truck traffic in the dual north- and south- bound lanes of this roadway is especially high on the 9-mile (15-km) section of NM 136 between the international border and an intermodal railway facility located in the USA state of New Mexico. Prior to this rehabilitation project, the structural cross-section of NM 136 consisted of 4.5 to 6.0 inches (110 to 150 mm) of asphalt on 5.0 to 6.0 inches (130 to 150 mm) of coarse-grained soils. Prior to this project on NM 136, NMDOT had very little experience with concrete pavements and none with continuously reinforced concrete pavements (CRCPs). The structural design for this rehabilitation project utilized the existing asphalt pavement as a satisfactory base for the CRCP by milling 1.5 inches (40 mm) of the existing asphalt concrete (AC) pavement and applying a 1.5-inch (40-mm) AC levelling course followed by the CRCP. This paper presents the design and construction related details of the NM 136 CRCP project.
{"title":"Long-Life Pavement for Users of an International Roadway in New Mexico","authors":"S. Tyson, S. Tayabji","doi":"10.33593/v38reo2p","DOIUrl":"https://doi.org/10.33593/v38reo2p","url":null,"abstract":"A 36-lane-mile (60 lane-km) international roadway was rehabilitated in the United States of America (USA) during 2018 by the New Mexico Department of Transportation (NMDOT) to provide uninterrupted long-life pavement performance for commercial users of the roadway. The southern border of the USA with the country of Mexico marks the starting point of New Mexico State Road 136 (NM 136), a four-lane divided roadway that carries heavily-loaded trucks associated with the United States–Mexico–Canada Agreement (USMCA), formerly the North American Free Trade Agreement (NAFTA). Truck traffic in the dual north- and south- bound lanes of this roadway is especially high on the 9-mile (15-km) section of NM 136 between the international border and an intermodal railway facility located in the USA state of New Mexico. Prior to this rehabilitation project, the structural cross-section of NM 136 consisted of 4.5 to 6.0 inches (110 to 150 mm) of asphalt on 5.0 to 6.0 inches (130 to 150 mm) of coarse-grained soils. Prior to this project on NM 136, NMDOT had very little experience with concrete pavements and none with continuously reinforced concrete pavements (CRCPs). The structural design for this rehabilitation project utilized the existing asphalt pavement as a satisfactory base for the CRCP by milling 1.5 inches (40 mm) of the existing asphalt concrete (AC) pavement and applying a 1.5-inch (40-mm) AC levelling course followed by the CRCP. This paper presents the design and construction related details of the NM 136 CRCP project.","PeriodicalId":265129,"journal":{"name":"Proceedings of the 12th International Conference on Concrete Pavements","volume":"100 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129337726","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Jointed precast concrete pavement was recently used to reconstruct large multi-lane areas of one of the busiest areas of Interstate H-1 near Honolulu, Hawai'i, USA. The design-build project was awarded in early January 2018 and more that 1200 precast panels were designed, fabricated and installed less than 7 months later using mostly 8-hour overnight work windows. There were several unusual and innovative aspects to this project, including: (1) variation in the type and layout of joints when replacing travel lanes with rectangular precast panels adjacent to existing skewed, random-length cast-in-place panels; (2) the use of ground-penetrating radar to map original pavement structures that varied greatly along the project length and between lanes; (3) the development of ``3-D'' design models for the new surface to improve ride quality and cross-slope; (4) the use of ``3-D'' panel fabrication techniques; (5) the use of laser-controlled construction equipment to construct contoured foundation surfaces that fully support the non-planar precast panels and allow immediate temporary use without grout, thereby extending productivity in short overnight work windows; (6) the use of optimized dowel placement (below mid-depth) and headed ``dowel-in'' tie assemblies to reduce slot sizes, improve panel integrity, and reduce panel grout requirements; (7) the placement of temporary asphalt layers to eliminate major drop-offs between lanes during construction; and (8) the development of specially shaped transition panels and bridge approach panels. This paper describes the unique aspects of precast pavement design and construction for this project and presents ``lessons learned'' and recommendations developed from the project.
{"title":"Recent Advances In Jointed Precast Concrete Paving: Hawai’i H-1 Reconstruction","authors":"P. Smith, M. Snyder","doi":"10.33593/xzpbm95w","DOIUrl":"https://doi.org/10.33593/xzpbm95w","url":null,"abstract":"Jointed precast concrete pavement was recently used to reconstruct large multi-lane areas of one of the busiest areas of Interstate H-1 near Honolulu, Hawai'i, USA. The design-build project was awarded in early January 2018 and more that 1200 precast panels were designed, fabricated and installed less than 7 months later using mostly 8-hour overnight work windows. There were several unusual and innovative aspects to this project, including: (1) variation in the type and layout of joints when replacing travel lanes with rectangular precast panels adjacent to existing skewed, random-length cast-in-place panels; (2) the use of ground-penetrating radar to map original pavement structures that varied greatly along the project length and between lanes; (3) the development of ``3-D'' design models for the new surface to improve ride quality and cross-slope; (4) the use of ``3-D'' panel fabrication techniques; (5) the use of laser-controlled construction equipment to construct contoured foundation surfaces that fully support the non-planar precast panels and allow immediate temporary use without grout, thereby extending productivity in short overnight work windows; (6) the use of optimized dowel placement (below mid-depth) and headed ``dowel-in'' tie assemblies to reduce slot sizes, improve panel integrity, and reduce panel grout requirements; (7) the placement of temporary asphalt layers to eliminate major drop-offs between lanes during construction; and (8) the development of specially shaped transition panels and bridge approach panels. This paper describes the unique aspects of precast pavement design and construction for this project and presents ``lessons learned'' and recommendations developed from the project.","PeriodicalId":265129,"journal":{"name":"Proceedings of the 12th International Conference on Concrete Pavements","volume":"49 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116100563","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A. Mateos, Miguel A. Millan, J. Harvey, R. Wu, J. Paniagua, F. Paniagua
Concrete moisture-related and thermal (hygrothermal) actions are known to have a large impact on the performance of concrete pavements. Despite that, current mechanistic-empirical design procedures oversimplify the prediction of these actions and their effects on the structure of the pavement. This paper evaluates the most common simplifications adopted by current mechanistic-empirical design procedures. The evaluation is based on the experimental data collected from fifteen thin bonded concrete overlay of asphalt pavements that were instrumented with sensors to measure the structural and hygrothermal response. The experimental data included the response of the slabs under the ambient environment, measured during fifteen months, and the response measured under the wheel of the Heavy Vehicle Simulator. The analysis of the experimental data shows that some simplifications adopted by current mechanistic-empirical design procedures lead to a considerable underestimation of the effects of thermal and moisture-related actions. The study emphasizes the need for a better understanding of a number of phenomena before a fully realistic modeling of the hygrothermal actions in concrete pavements can be achieved. Among those phenomena are concrete tensile creep, slab- base interaction, and concrete moisture content effect on the coefficient of thermal expansion.
{"title":"Consideration of the Hygrothermal Actions in Concrete Pavement Design Procedures: Do we Follow the Right Approach?","authors":"A. Mateos, Miguel A. Millan, J. Harvey, R. Wu, J. Paniagua, F. Paniagua","doi":"10.33593/rpya0kma","DOIUrl":"https://doi.org/10.33593/rpya0kma","url":null,"abstract":"Concrete moisture-related and thermal (hygrothermal) actions are known to have a large impact on the performance of concrete pavements. Despite that, current mechanistic-empirical design procedures oversimplify the prediction of these actions and their effects on the structure of the pavement. This paper evaluates the most common simplifications adopted by current mechanistic-empirical design procedures. The evaluation is based on the experimental data collected from fifteen thin bonded concrete overlay of asphalt pavements that were instrumented with sensors to measure the structural and hygrothermal response. The experimental data included the response of the slabs under the ambient environment, measured during fifteen months, and the response measured under the wheel of the Heavy Vehicle Simulator. The analysis of the experimental data shows that some simplifications adopted by current mechanistic-empirical design procedures lead to a considerable underestimation of the effects of thermal and moisture-related actions. The study emphasizes the need for a better understanding of a number of phenomena before a fully realistic modeling of the hygrothermal actions in concrete pavements can be achieved. Among those phenomena are concrete tensile creep, slab- base interaction, and concrete moisture content effect on the coefficient of thermal expansion.","PeriodicalId":265129,"journal":{"name":"Proceedings of the 12th International Conference on Concrete Pavements","volume":"403 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115276266","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Tara L. Cavalline, M. Snyder, T. Cackler, P. Taylor
Recycling concrete pavements has been a common practice in the US for decades, and recently, public agencies have been more closely examining recycling opportunities. Reasons supporting recycling include the diminishing quantity of good natural materials, economics, improved project execution, minimizing traffic disruption, and supporting sustainability goals. Many states, however, have specifications or policies that restrict concrete pavement recycling. The contracting industry may overlook opportunities to use recycled concrete aggregates (RCAs) due to a lack of familiarity with technical requirements or uncertainty of performance. The National Concrete Pavement Technology Center (CP Tech Center) recently completed a comprehensive set of technical resources for the Federal Highway Administration to assist practitioners with sound approaches to project selection, scoping and construction requirements to support increased use of recycled concrete pavement materials. This paper describes the results of a 2016 survey of agency and industry RCA usage, presents an overview of the technical resources prepared as part of this initiative, and presents recommendations for supporting broader application of recycling concrete pavement materials.
{"title":"Guidance for Increasing the Use of Recycled Concrete Pavement Materials","authors":"Tara L. Cavalline, M. Snyder, T. Cackler, P. Taylor","doi":"10.33593/18tg9ll7","DOIUrl":"https://doi.org/10.33593/18tg9ll7","url":null,"abstract":"Recycling concrete pavements has been a common practice in the US for decades, and recently, public agencies have been more closely examining recycling opportunities. Reasons supporting recycling include the diminishing quantity of good natural materials, economics, improved project execution, minimizing traffic disruption, and supporting sustainability goals. Many states, however, have specifications or policies that restrict concrete pavement recycling. The contracting industry may overlook opportunities to use recycled concrete aggregates (RCAs) due to a lack of familiarity with technical requirements or uncertainty of performance. The National Concrete Pavement Technology Center (CP Tech Center) recently completed a comprehensive set of technical resources for the Federal Highway Administration to assist practitioners with sound approaches to project selection, scoping and construction requirements to support increased use of recycled concrete pavement materials. This paper describes the results of a 2016 survey of agency and industry RCA usage, presents an overview of the technical resources prepared as part of this initiative, and presents recommendations for supporting broader application of recycling concrete pavement materials.","PeriodicalId":265129,"journal":{"name":"Proceedings of the 12th International Conference on Concrete Pavements","volume":"237 2 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114211212","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The effectiveness of using pre-wetted lightweight aggregate (LWA) for internal curing was investigated based on a laboratory testing program with a primary objective to reduce or mitigate curing related shrinkage (i.e. autogenous), as this could pave the way for using LWA in concrete for repair projects such as bonded overlays or new construction (e.g. JPCP projects). A concern with the use of LWA is the high absorption coefficient and potential negative impact on freeze-thaw resistance. A laboratory study was developed to evaluate compressive strength and key durability properties, such as rapid chloride permeability, RCP, sorptivity, and freeze-thaw (F-T) resistance (i.e. combined resistance to internal cracking and surface scaling in the presence of a 3% salt solution on the surface during repeated F-T cycles). Concrete mix variables were LWA content (25% and 40%). A total of three air-entrained batches were produced. Total cementitious content was 390 kg/m3 (658 lb/yd3) with 30% slag cement. The major findings are: Autogenous shrinkage can be mitigated by using pre-wetted fine LWA at a 25% to 40% volume content of total fine aggregate. Excellent F-T resistance with respect to internal cracking and surface salt scaling was found for LWA contents of 25% or 40%. A silane surface treatment was found partially effective as surface scaling accelerates once a fully saturated pore condition occurs. This suggests that the hydrophobic treatment prevents pressure relief by air-voids and "surface-breathing".
{"title":"Evaluation of Internal Curing and Hydrophobic Surface Treatment on the Durability of Concrete","authors":"Yu-hong Zhong, W. Hansen","doi":"10.33593/txkqro30","DOIUrl":"https://doi.org/10.33593/txkqro30","url":null,"abstract":"The effectiveness of using pre-wetted lightweight aggregate (LWA) for internal curing was investigated based on a laboratory testing program with a primary objective to reduce or mitigate curing related shrinkage (i.e. autogenous), as this could pave the way for using LWA in concrete for repair projects such as bonded overlays or new construction (e.g. JPCP projects). A concern with the use of LWA is the high absorption coefficient and potential negative impact on freeze-thaw resistance. A laboratory study was developed to evaluate compressive strength and key durability properties, such as rapid chloride permeability, RCP, sorptivity, and freeze-thaw (F-T) resistance (i.e. combined resistance to internal cracking and surface scaling in the presence of a 3% salt solution on the surface during repeated F-T cycles). Concrete mix variables were LWA content (25% and 40%). A total of three air-entrained batches were produced. Total cementitious content was 390 kg/m3 (658 lb/yd3) with 30% slag cement. The major findings are: Autogenous shrinkage can be mitigated by using pre-wetted fine LWA at a 25% to 40% volume content of total fine aggregate. Excellent F-T resistance with respect to internal cracking and surface salt scaling was found for LWA contents of 25% or 40%. A silane surface treatment was found partially effective as surface scaling accelerates once a fully saturated pore condition occurs. This suggests that the hydrophobic treatment prevents pressure relief by air-voids and \"surface-breathing\".","PeriodicalId":265129,"journal":{"name":"Proceedings of the 12th International Conference on Concrete Pavements","volume":"30 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126667785","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The well-known bump-at-the-end-of-the-bridge often involves the joint between the bridge approach slab (BAS) and a bridge deck as the root cause has been a recurring nationwide issue over the years. DOTs have reported that the roughness and the associated slab cracking near this joint have significantly reduced ride quality. Recent field investigations have found that similar problems can also develop at the BAS – pavement joint due to erosion that has taken place underneath it. Considerations are provided in this paper with respect to how potential erosion could be better addressed by addressing the factors that affect it in the design of the BAS thickness. An approach previously developed by the research team is briefly introduced to facilitate the prediction of erosion damage occurring underneath the BAS – pavement joint. As a means to improve the current methodology for designing the thickness of BASs, this paper elaborates a modified mechanistic – empirical design procedure using a an “erosion-based slab thickness” concept to account for the effect of the erosion damage on the structural capacity of the BAS; reliability considerations with respect to the cracking performance of BASs are also provided to facilitate the design process.
{"title":"NEW CONCEPTS FOR DESIGNING BRIDGE APPROACH SLABS","authors":"Peizhi Sun, D. Zollinger","doi":"10.33593/g19tmttd","DOIUrl":"https://doi.org/10.33593/g19tmttd","url":null,"abstract":"The well-known bump-at-the-end-of-the-bridge often involves the joint between the bridge approach slab (BAS) and a bridge deck as the root cause has been a recurring nationwide issue over the years. DOTs have reported that the roughness and the associated slab cracking near this joint have significantly reduced ride quality. Recent field investigations have found that similar problems can also develop at the BAS – pavement joint due to erosion that has taken place underneath it. Considerations are provided in this paper with respect to how potential erosion could be better addressed by addressing the factors that affect it in the design of the BAS thickness. An approach previously developed by the research team is briefly introduced to facilitate the prediction of erosion damage occurring underneath the BAS – pavement joint. As a means to improve the current methodology for designing the thickness of BASs, this paper elaborates a modified mechanistic – empirical design procedure using a an “erosion-based slab thickness” concept to account for the effect of the erosion damage on the structural capacity of the BAS; reliability considerations with respect to the cracking performance of BASs are also provided to facilitate the design process.","PeriodicalId":265129,"journal":{"name":"Proceedings of the 12th International Conference on Concrete Pavements","volume":"17 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131445680","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
S. Sadati, Xin Wang, P. Taylor, J. Kevern, Kejin Wang
The resistance of concrete to freeze-thaw (F-T) greatly depends on the characteristics of the concrete air-void system, such as the air content, size, and distribution. These air-void characteristics are influenced by every step of concrete production, from material selection and mixture proportioning to mixing, and placing. The research presented in this paper summarizes the observations from a comprehensive study that combined the in-situ performance of highway concrete with laboratory investigations. The field investigation involved determining the minimum requirements of air-void systems (AVS) for long-term durability against F-T cycles. In collaboration with several state agencies across the United States and Canada, core specimens were obtained for studying the properties of AVS resulting in different F-T conditions. Hardened air content, spacing factor, and specific surface of air-voids were determined for the extracted cores. The observations were supplemented by data obtained from a wide range of modern paving concrete mixtures. AVS characteristics were investigated using a variety of different techniques in fresh and hardened states. The main outcome of this research is a series of recommendations for minimum fresh and hardened AVS requirements to secure F-T durability.
{"title":"Air Void System Requirements for Durable Paving Concrete - Another Look","authors":"S. Sadati, Xin Wang, P. Taylor, J. Kevern, Kejin Wang","doi":"10.33593/a0mltw7m","DOIUrl":"https://doi.org/10.33593/a0mltw7m","url":null,"abstract":"The resistance of concrete to freeze-thaw (F-T) greatly depends on the characteristics of the concrete air-void system, such as the air content, size, and distribution. These air-void characteristics are influenced by every step of concrete production, from material selection and mixture proportioning to mixing, and placing. The research presented in this paper summarizes the observations from a comprehensive study that combined the in-situ performance of highway concrete with laboratory investigations. The field investigation involved determining the minimum requirements of air-void systems (AVS) for long-term durability against F-T cycles. In collaboration with several state agencies across the United States and Canada, core specimens were obtained for studying the properties of AVS resulting in different F-T conditions. Hardened air content, spacing factor, and specific surface of air-voids were determined for the extracted cores. The observations were supplemented by data obtained from a wide range of modern paving concrete mixtures. AVS characteristics were investigated using a variety of different techniques in fresh and hardened states. The main outcome of this research is a series of recommendations for minimum fresh and hardened AVS requirements to secure F-T durability.","PeriodicalId":265129,"journal":{"name":"Proceedings of the 12th International Conference on Concrete Pavements","volume":"39 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115060359","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Top-down drying in concrete pavement slabs causes differential drying shrinkage strains ($varepsilon_{sh}$), which may warp the slab and lead to cracking. Warping is typically represented by an equivalent temperature difference ($ETD_{sh}$) that will cause the same slab curvature as $varepsilon_{sh}$. However, the current $ETD_{sh}$ computation procedures are empirical and simplified. In this study, a poromechanistic-empirical (PME) procedure is proposed to compute time-dependent $ETD_{sh}$ for concrete pavements. The PME procedure integrates a diffusion model to predict the internal relative humidity with a poromechanistic model to calculate $varepsilon_{sh}$-profiles. Both models are calibrated based on differential drying experiments conducted on mortar prims from seven mixture designs. After applying an empirical correction for coarse aggregate volume, the developed $varepsilon_{sh}$-profiles are used to calculate $ETD_{sh}$ for an instrumented pavement section in Pennsylvania for validation. Higher sensitivity of the PME procedure compared to the current pavement design guide, AASHTOWare PavementME, to both mixture design and climate is demonstrated for four pavement sections. The largest difference in $ETD_{sh}$ among the climates is 33$^circ$C based on the PME procedure, as opposed to only 2$^circ$C by PavementME. PME $ETD_{sh}$ also shows the benefits of fly ash and low w/cm to mitigate warping, especially in dry non-freeze climates.
{"title":"Application of a poromechanistic-empirical drying shrinkage modeling approach to structural design of concrete pavements","authors":"M. Rangelov, S. Nassiri","doi":"10.33593/jqlg491h","DOIUrl":"https://doi.org/10.33593/jqlg491h","url":null,"abstract":"Top-down drying in concrete pavement slabs causes differential drying shrinkage strains ($varepsilon_{sh}$), which may warp the slab and lead to cracking. Warping is typically represented by an equivalent temperature difference ($ETD_{sh}$) that will cause the same slab curvature as $varepsilon_{sh}$. However, the current $ETD_{sh}$ computation procedures are empirical and simplified. In this study, a poromechanistic-empirical (PME) procedure is proposed to compute time-dependent $ETD_{sh}$ for concrete pavements. The PME procedure integrates a diffusion model to predict the internal relative humidity with a poromechanistic model to calculate $varepsilon_{sh}$-profiles. Both models are calibrated based on differential drying experiments conducted on mortar prims from seven mixture designs. After applying an empirical correction for coarse aggregate volume, the developed $varepsilon_{sh}$-profiles are used to calculate $ETD_{sh}$ for an instrumented pavement section in Pennsylvania for validation. Higher sensitivity of the PME procedure compared to the current pavement design guide, AASHTOWare PavementME, to both mixture design and climate is demonstrated for four pavement sections. The largest difference in $ETD_{sh}$ among the climates is 33$^circ$C based on the PME procedure, as opposed to only 2$^circ$C by PavementME. PME $ETD_{sh}$ also shows the benefits of fly ash and low w/cm to mitigate warping, especially in dry non-freeze climates.","PeriodicalId":265129,"journal":{"name":"Proceedings of the 12th International Conference on Concrete Pavements","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129491013","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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