Rapid Strength Concrete (RSC) slabs on six California jointed plain concrete pavement (JPCP) highway projects were surveyed. These projects had been previously surveyed in 2008 at 3-years of age and by 2018 had reached a service life of 13-years. Of the initial 5430 slabs examined in 2008, a total of 1493 RSC slabs, located on 12 traffic lanes, were observed and distress types recorded again in 2018. These slabs included both CTS and 4x4 RSC located in both inner and outer lanes. Only a small percentage (1.4%) of the 5,430 RSC slabs exhibited any distress in 2008 after 3-years' service and the increases were small over the next 10 years of service with the exception of transverse fatigue cracks. The transverse (top down fatigue) type of cracking had the highest percentage and largest increase of any distress type. The heavy truck outside lanes exhibited 21% transversely cracked RSC slabs and the inner passing lanes 3%. The outer truck lanes carried over 3 times more trucks than inner lanes. The RSC slabs were mostly 200-223 mm thick and thus susceptible to fatigue damage. The overall performance of the RSC slabs (both CTS and 4x4 RSC materials) were similar and considered to be outstanding over 13 years with a large majority expected to survive many more years.
{"title":"Long-Term Performance of Jointed Plain Concrete Pavement with Rapid Strength Concrete On California Highways","authors":"M. Darter","doi":"10.33593/2rh2xidw","DOIUrl":"https://doi.org/10.33593/2rh2xidw","url":null,"abstract":"Rapid Strength Concrete (RSC) slabs on six California jointed plain concrete pavement (JPCP) highway projects were surveyed. These projects had been previously surveyed in 2008 at 3-years of age and by 2018 had reached a service life of 13-years. Of the initial 5430 slabs examined in 2008, a total of 1493 RSC slabs, located on 12 traffic lanes, were observed and distress types recorded again in 2018. These slabs included both CTS and 4x4 RSC located in both inner and outer lanes. Only a small percentage (1.4%) of the 5,430 RSC slabs exhibited any distress in 2008 after 3-years' service and the increases were small over the next 10 years of service with the exception of transverse fatigue cracks. The transverse (top down fatigue) type of cracking had the highest percentage and largest increase of any distress type. The heavy truck outside lanes exhibited 21% transversely cracked RSC slabs and the inner passing lanes 3%. The outer truck lanes carried over 3 times more trucks than inner lanes. The RSC slabs were mostly 200-223 mm thick and thus susceptible to fatigue damage. The overall performance of the RSC slabs (both CTS and 4x4 RSC materials) were similar and considered to be outstanding over 13 years with a large majority expected to survive many more years.","PeriodicalId":265129,"journal":{"name":"Proceedings of the 12th International Conference on Concrete Pavements","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132392069","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}
Over the last couple of years, new rapid-hardening concretes were developed. They do not only stand out by their high early strength, in excess of 20 MPa already 90 minutes after setting, but are also adjustable to the needs of the construction site in regards to fresh concrete properties and setting behavior. This allows the rapid-hardening concrete to be placed using traditional means and the construction program to be optimized in order to perform the renewals during very short closure windows. After many years of usage, the single runway at Sabiha Gökcen International Airport Istanbul was in need of large-scale renewals due to severe damages in the high wear areas around the centerline. But, with it being the only runway at the airport, closing it for multiple weeks to perform the renewal was not an option. The nightly closure of only 5 hours, due to late-evening and early-morning flights, placed additional demands on the rapid-hardening concrete, the logistics of the construction site and the concrete's long-term durability for a permanent solution. This article presents the step-by-step over-night renewals at Sabiha Gökcen Airport, which is the largest project ever performed involving rapid-hardening concrete. Each night up to 5 slabs (94 m2) of the runway were replaced for a total area of 8700 m2 over 117 nights between March and September 2018. Such large area applications without affecting regular airport operations are possible thanks to the latest generation of rapid-hardening cement and this article shows these possibilities to project owners, design engineers, and contractors.
{"title":"Over-night Renewals of the Concrete Runway at Sabiha Gökcen International Airport Istanbul","authors":"M. Bäuml, Jakob Melchior, Felicia Constandopoulos","doi":"10.33593/nj0oxhb0","DOIUrl":"https://doi.org/10.33593/nj0oxhb0","url":null,"abstract":"Over the last couple of years, new rapid-hardening concretes were developed. They do not only stand out by their high early strength, in excess of 20 MPa already 90 minutes after setting, but are also adjustable to the needs of the construction site in regards to fresh concrete properties and setting behavior. This allows the rapid-hardening concrete to be placed using traditional means and the construction program to be optimized in order to perform the renewals during very short closure windows. After many years of usage, the single runway at Sabiha Gökcen International Airport Istanbul was in need of large-scale renewals due to severe damages in the high wear areas around the centerline. But, with it being the only runway at the airport, closing it for multiple weeks to perform the renewal was not an option. The nightly closure of only 5 hours, due to late-evening and early-morning flights, placed additional demands on the rapid-hardening concrete, the logistics of the construction site and the concrete's long-term durability for a permanent solution. This article presents the step-by-step over-night renewals at Sabiha Gökcen Airport, which is the largest project ever performed involving rapid-hardening concrete. Each night up to 5 slabs (94 m2) of the runway were replaced for a total area of 8700 m2 over 117 nights between March and September 2018. Such large area applications without affecting regular airport operations are possible thanks to the latest generation of rapid-hardening cement and this article shows these possibilities to project owners, design engineers, and contractors.","PeriodicalId":265129,"journal":{"name":"Proceedings of the 12th International Conference on Concrete Pavements","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132532106","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":null,"pages":null},"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":null,"pages":null},"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":null,"pages":null},"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":null,"pages":null},"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":null,"pages":null},"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":null,"pages":null},"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":null,"pages":null},"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":null,"pages":null},"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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