Nancy Beltran, Abbasali TaghaviGhalesar, R. Rogers, C. Carrasco
The rapid energy sector development and the strong increase in vehicle axle loads has resulted in premature failure of asphalt pavements and, as a consequence, concrete pavements are being considered. However, current design methods assume the significantly heavier vehicle loads will have an elastic impact on the pavement layers and has led pavement engineers to thicken the concrete layer to withstand the heavy loads resulting in a more costly option compared to an asphalt pavement design. Moreover, the current design procedure of concrete pavements discretize the supporting layers using the Winkler foundation model, which makes it incapable of properly considering the impact that heavier truck loads have on the foundation layers. For this reason, researchers at the University of Texas at El Paso (UTEP) developed the Rigid Pavement Analysis System (RPAS), a finite element analysis program that has the capabilities of modeling the foundation layers using a 3-D foundation model, which considers the additive impact of adjacent wheel loads in the subgrade. RPAS has linear elastic theory capabilities and can also be used for the analysis of asphalt pavements when considering the appropriate material properties. This paper presents a comparison study conducted for the Texas Department of Transportation (TxDOT), Odessa District, between a hot mix asphalt (HMA) pavement design and a Portland cement concrete (PCC) pavement design to evaluate the effects that heavy loads have on each pavement layer responses (stresses and strains). The results determined that the PCC pavement provided adequate concrete stresses and significantly reduced the subgrade strains.
{"title":"Comparison of Pavement Layer Responses Between HMA/PCC Pavement Designs with Heavy Vehicle Loads Using RPAS","authors":"Nancy Beltran, Abbasali TaghaviGhalesar, R. Rogers, C. Carrasco","doi":"10.33593/um4og534","DOIUrl":"https://doi.org/10.33593/um4og534","url":null,"abstract":"The rapid energy sector development and the strong increase in vehicle axle loads has resulted in premature failure of asphalt pavements and, as a consequence, concrete pavements are being considered. However, current design methods assume the significantly heavier vehicle loads will have an elastic impact on the pavement layers and has led pavement engineers to thicken the concrete layer to withstand the heavy loads resulting in a more costly option compared to an asphalt pavement design. Moreover, the current design procedure of concrete pavements discretize the supporting layers using the Winkler foundation model, which makes it incapable of properly considering the impact that heavier truck loads have on the foundation layers. For this reason, researchers at the University of Texas at El Paso (UTEP) developed the Rigid Pavement Analysis System (RPAS), a finite element analysis program that has the capabilities of modeling the foundation layers using a 3-D foundation model, which considers the additive impact of adjacent wheel loads in the subgrade. RPAS has linear elastic theory capabilities and can also be used for the analysis of asphalt pavements when considering the appropriate material properties. This paper presents a comparison study conducted for the Texas Department of Transportation (TxDOT), Odessa District, between a hot mix asphalt (HMA) pavement design and a Portland cement concrete (PCC) pavement design to evaluate the effects that heavy loads have on each pavement layer responses (stresses and strains). The results determined that the PCC pavement provided adequate concrete stresses and significantly reduced the subgrade strains.","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":"131913237","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}
Asset management of infrastructure is fundamental for maintenance planning and preservation of common property. A robust testing program is needed to assess the present-day status and for proper actions in time to minimize the ongoing depreciation of value. As a matter of fact, Portland Cement Concrete pavements show very little deterioration even after many years in service. Thus, it may be difficult to accurately predict the present asset value, other than using linear relations to the presumed design life. The primary reason for failure is cracking in concrete pavements, so assessing the dissipated energy from the load-deformation relation from a given load could be utilized for the purpose. The dissipated energy, i.e. the work data can be assessed by a falling weight deflectometer test, mimicking the passing of a truck or aircraft wheel load. In the present study, dynamic field data are evaluated, and the input data needed for the fracture mechanics model are used to predict the pavement life regarding cracking. To predict fracture energy and assess rolling resistance as well in concrete pavements, we need to consider the energy balance of the pavement system. To assess dissipated energy, falling weight deflectometer time histories are used to evaluate the pavement contribution to rolling resistance. Such analyses include all layers in the structure including the subgrade, so in the present case a way of sorting the dissipation at various depths is investigated. Field data were collected from a site, at mid-life of the predicted design life. The failure was confirmed several years later, and the remaining life was compared with the assumption that the dissipated energy near the edge was enough to initiate the cracks within the actual time to failure. Conversely, the dissipation at the mid-slab position was below the limit. The data from the field test were also used as an input for a finite element model to see if it was viable to further improve the prediction. The method seems to be promising, but more data are needed as the present set only represents the mid-life status.
{"title":"Relating Field Energy Attenuation in Portland Cement Concrete Pavements to Fracture Mechanics","authors":"C. Lenngren, M. Hernández","doi":"10.33593/0xmxe2jw","DOIUrl":"https://doi.org/10.33593/0xmxe2jw","url":null,"abstract":"Asset management of infrastructure is fundamental for maintenance planning and preservation of common property. A robust testing program is needed to assess the present-day status and for proper actions in time to minimize the ongoing depreciation of value. As a matter of fact, Portland Cement Concrete pavements show very little deterioration even after many years in service. Thus, it may be difficult to accurately predict the present asset value, other than using linear relations to the presumed design life. The primary reason for failure is cracking in concrete pavements, so assessing the dissipated energy from the load-deformation relation from a given load could be utilized for the purpose. The dissipated energy, i.e. the work data can be assessed by a falling weight deflectometer test, mimicking the passing of a truck or aircraft wheel load. In the present study, dynamic field data are evaluated, and the input data needed for the fracture mechanics model are used to predict the pavement life regarding cracking. To predict fracture energy and assess rolling resistance as well in concrete pavements, we need to consider the energy balance of the pavement system. To assess dissipated energy, falling weight deflectometer time histories are used to evaluate the pavement contribution to rolling resistance. Such analyses include all layers in the structure including the subgrade, so in the present case a way of sorting the dissipation at various depths is investigated. Field data were collected from a site, at mid-life of the predicted design life. The failure was confirmed several years later, and the remaining life was compared with the assumption that the dissipated energy near the edge was enough to initiate the cracks within the actual time to failure. Conversely, the dissipation at the mid-slab position was below the limit. The data from the field test were also used as an input for a finite element model to see if it was viable to further improve the prediction. The method seems to be promising, but more data are needed as the present set only represents the mid-life status.","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":"124745752","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}
Pia Mandahus, L. Eberhardsteiner, B. Pichler, M. Aminbaghai, R. Blab
About a half of the Austrian highways are rigid pavement constructions, and increasingly more money has to be invested in their renovation and redevelopment. However, there are different approaches for the evaluation of the condition assessment of concrete pavements. The aim of the research presented in this paper is a concept for assessing the condition of a road section in rigid pavement. This consists of a structural and a visual assessment scheme for selecting appropriate maintenance actions. For the verification of this new method of assessment of the structural condition of concrete pavements, several field tests were examined. Furthermore, a case study was carried out to examine the level of influence of several input parameter. This analysis shows that the influence of the layer thickness is very high, while the influence of the modulus of elasticity of the existing concrete is significant lower. The FWD measurements were carried out radial (instead of linear) for the first time. The results show possible inhomogeneities in the subgrade or in the bedding, which would not be recognized by the standard linear measurements. With the results from the already mentioned measurements, the remaining service life of the test tracks could be calculated.
{"title":"Validation Of A New Method For Determining The Remaining Service Life Of Rigid Pavements","authors":"Pia Mandahus, L. Eberhardsteiner, B. Pichler, M. Aminbaghai, R. Blab","doi":"10.33593/2km27z9r","DOIUrl":"https://doi.org/10.33593/2km27z9r","url":null,"abstract":"About a half of the Austrian highways are rigid pavement constructions, and increasingly more money has to be invested in their renovation and redevelopment. However, there are different approaches for the evaluation of the condition assessment of concrete pavements. The aim of the research presented in this paper is a concept for assessing the condition of a road section in rigid pavement. This consists of a structural and a visual assessment scheme for selecting appropriate maintenance actions. For the verification of this new method of assessment of the structural condition of concrete pavements, several field tests were examined. Furthermore, a case study was carried out to examine the level of influence of several input parameter. This analysis shows that the influence of the layer thickness is very high, while the influence of the modulus of elasticity of the existing concrete is significant lower. The FWD measurements were carried out radial (instead of linear) for the first time. The results show possible inhomogeneities in the subgrade or in the bedding, which would not be recognized by the standard linear measurements. With the results from the already mentioned measurements, the remaining service life of the test tracks could be calculated.","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":"114563186","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}
Interest in roller-compacted concrete (RCC) pavement has been increasing because of its low initial cost, construction efficiency, and ability to open to traffic early. Current RCC mixture design methods do not directly consider the aggregate source or optimal cement content. An experimental testing plan was developed to batch RCC mixtures with several aggregate sources, gradations, paste contents, and water-cement (w/c) ratios. Each aggregate blend was compacted in order to determine the intergranular volume of voids. The volume of cement paste was varied to underfill, equifill, and overfill the compacted aggregate voids. Green properties (green strength, green modulus, and softening modulus) were measured on the lab compacted specimens to assess the fresh RCC capacity, stability, and plasticity. Green and hardened properties were then related to the RCC mixture volumetric parameters. Green properties were sensitive to aggregate type and gradation, ratio of voids filled by paste, w/c ratio, and total paste content, which all affected the mixes adhesion and shear resistance. In most cases, high cement contents did not improve green or hardened properties. RCC mixtures containing crushed aggregates achieved maximum green strength and stability with underfilled voids, while RCC with rounded aggregates required overfilling the voids. Workability (Vebe time) measurements were not sensitive unless voids were overfilled and not highly sensitive to w/c ratio.
{"title":"Aggregate Source Effects on RCC Green Properties","authors":"Jordan Ouellet, G. Scott, J. Roesler","doi":"10.33593/oyhv8xl1","DOIUrl":"https://doi.org/10.33593/oyhv8xl1","url":null,"abstract":"Interest in roller-compacted concrete (RCC) pavement has been increasing because of its low initial cost, construction efficiency, and ability to open to traffic early. Current RCC mixture design methods do not directly consider the aggregate source or optimal cement content. An experimental testing plan was developed to batch RCC mixtures with several aggregate sources, gradations, paste contents, and water-cement (w/c) ratios. Each aggregate blend was compacted in order to determine the intergranular volume of voids. The volume of cement paste was varied to underfill, equifill, and overfill the compacted aggregate voids. Green properties (green strength, green modulus, and softening modulus) were measured on the lab compacted specimens to assess the fresh RCC capacity, stability, and plasticity. Green and hardened properties were then related to the RCC mixture volumetric parameters. Green properties were sensitive to aggregate type and gradation, ratio of voids filled by paste, w/c ratio, and total paste content, which all affected the mixes adhesion and shear resistance. In most cases, high cement contents did not improve green or hardened properties. RCC mixtures containing crushed aggregates achieved maximum green strength and stability with underfilled voids, while RCC with rounded aggregates required overfilling the voids. Workability (Vebe time) measurements were not sensitive unless voids were overfilled and not highly sensitive to w/c ratio.","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":"116569128","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}
David Ov, R. Breitenbücher, M. Radenberg, Dominik Twer
Joint sealants as indispensable filling systems in jointed plain concrete pavements (JPCP) are permanently exposed to various stresses during their service life, which often leads to a replacement of the sealing after approx. 7 to 10 years. Aside from seasonal unsteady climatic changes, the cyclical stresses caused by traffic and the ageing of joint sealants are especially significant. Considering the rising number of damages that occur within the overall "joint" system, an increased demand for a durable solution is requested as it is a relevant element for the life cycle costs of concrete pavements. In this context, a testing and ageing method was developed which comprises of the entire "joint" system, including the saw-cut concrete joint flanks, the primer as well as the joint sealant. This procedure depicts the decisive scenarios of in-situ stresses and allows the characterization of joint sealants. For this purpose, specimens were subjected to horizontal and vertical loads (static/cyclic) as well as to various ageing effects (temperature conditioning, UV-conditioning and freeze-thaw-cycles). After conditioning, a significant influence of the artificial ageing on the residual strength was observed in the tensile/shear tests. By comparing the artificially aged samples tested in the laboratory with extracted and in-situ aged samples, a reliable correlation was determined. Considering these system tests an initial approach was established which enables the evaluation of joint sealants in both unaged and artificially aged conditions on the basis of scientific parameters and limits.
{"title":"Innovative test method for the reliable evaluation of joint sealants in concrete pavements","authors":"David Ov, R. Breitenbücher, M. Radenberg, Dominik Twer","doi":"10.33593/x3x4t4o9","DOIUrl":"https://doi.org/10.33593/x3x4t4o9","url":null,"abstract":"Joint sealants as indispensable filling systems in jointed plain concrete pavements (JPCP) are permanently exposed to various stresses during their service life, which often leads to a replacement of the sealing after approx. 7 to 10 years. Aside from seasonal unsteady climatic changes, the cyclical stresses caused by traffic and the ageing of joint sealants are especially significant. Considering the rising number of damages that occur within the overall \"joint\" system, an increased demand for a durable solution is requested as it is a relevant element for the life cycle costs of concrete pavements. In this context, a testing and ageing method was developed which comprises of the entire \"joint\" system, including the saw-cut concrete joint flanks, the primer as well as the joint sealant. This procedure depicts the decisive scenarios of in-situ stresses and allows the characterization of joint sealants. For this purpose, specimens were subjected to horizontal and vertical loads (static/cyclic) as well as to various ageing effects (temperature conditioning, UV-conditioning and freeze-thaw-cycles). After conditioning, a significant influence of the artificial ageing on the residual strength was observed in the tensile/shear tests. By comparing the artificially aged samples tested in the laboratory with extracted and in-situ aged samples, a reliable correlation was determined. Considering these system tests an initial approach was established which enables the evaluation of joint sealants in both unaged and artificially aged conditions on the basis of scientific parameters and limits.","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":"127195460","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}
R. K. Jain, P. L. Bongirwar, U. Kulkarni, G.V.M. Kiran Babu, Raman Kumar
Black Cotton (BC) soil is present in large parts of India. This soil absorbs lot of water while getting wet and swells even more than 50% which is called Free Swelling Index (FSI). If swelling is prevented, it exerts lot of pressure on the pavement and causes all types of cracks. The CBR of this soil is between 2% to 3.5%. Indian design guidelines provide for Cement Concrete Pavement (CCP), a minimum of 8% CBR for subgrade. While constructing CCP on BC soils special precautions are needed, otherwise distresses will develop. If the new pavement is to be constructed, the remedy lies in removal of the BC soil up to a depth of about 2m from Natural Ground Level (NGL), and treating the underlying soil in construction prism with lime and cement ensuring 12% CBR and 98% compaction. In this case study a 10m wide CCP was built on existing 7m wide flexible pavement by removing the bituminous layer overlaid with Granular Sub-base and Roller Compacted Concrete. Fresh shoulders 1.5m wide on each side were added. The road failed prematurely. Study involved investigation of reasons for the failure of CCP on a highway. The distress is found to be in the form of wide and long longitudinal cracks with faulting at a few places, as well as transverse cracks, multiple cracks and corner breaks in some panels. In-situ stabilisation of Black Cotton Soil is suggested as an effective remedy to mitigate the problem to a large extent.
{"title":"Causes Of Distress In Cement Concrete Pavement On Black Cotton Soil And Remedy","authors":"R. K. Jain, P. L. Bongirwar, U. Kulkarni, G.V.M. Kiran Babu, Raman Kumar","doi":"10.33593/vfyy1ruu","DOIUrl":"https://doi.org/10.33593/vfyy1ruu","url":null,"abstract":"Black Cotton (BC) soil is present in large parts of India. This soil absorbs lot of water while getting wet and swells even more than 50% which is called Free Swelling Index (FSI). If swelling is prevented, it exerts lot of pressure on the pavement and causes all types of cracks. The CBR of this soil is between 2% to 3.5%. Indian design guidelines provide for Cement Concrete Pavement (CCP), a minimum of 8% CBR for subgrade. While constructing CCP on BC soils special precautions are needed, otherwise distresses will develop. If the new pavement is to be constructed, the remedy lies in removal of the BC soil up to a depth of about 2m from Natural Ground Level (NGL), and treating the underlying soil in construction prism with lime and cement ensuring 12% CBR and 98% compaction. In this case study a 10m wide CCP was built on existing 7m wide flexible pavement by removing the bituminous layer overlaid with Granular Sub-base and Roller Compacted Concrete. Fresh shoulders 1.5m wide on each side were added. The road failed prematurely. Study involved investigation of reasons for the failure of CCP on a highway. The distress is found to be in the form of wide and long longitudinal cracks with faulting at a few places, as well as transverse cracks, multiple cracks and corner breaks in some panels. In-situ stabilisation of Black Cotton Soil is suggested as an effective remedy to mitigate the problem to a large extent.","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":"127490103","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 jointed plain concrete pavement represents a reliable, historically proven technical solution for highly loaded roads, highways, airports and other industrial surfaces. Excellent resistance to permanent deformations (rutting) and also durability and maintenance costs play key roles in assessing the economic benefits, rehabilitation plans, traffic closures, consumption and recycling of materials. In the history of concrete pavement construction, slow-to-normal hardening Portland cement was used in Czechoslovakia during the 1970s-1980s. The pavements are being replaced after 40-50 years of service, mostly due to vertical slab displacements due to missing dowel bars. However, pavements built after 1996 used rapid hardening cements, resulting in long-term surface cracking and decreased durability. In order to build durable concrete pavements, slower hardening slag-blended binders were designed and tested in the restrained ring shrinkage test and in isothermal calorimetry. Corresponding concretes were tested mainly for the compressive/tensile strength evolution and deicing salt-frost scaling to meet current specifications. The pilot project was executed on a 14 km highway, where a unique temperature-strain monitoring system was installed to provide long-term data from the concrete pavement. A thermo-mechanical coupled model served for data validation, showing a beneficial role of slower hydration kinetics. Continuous monitoring interim results at 24 months have revealed small curling induced by drying and the overall small differential shrinkage of the slab.
{"title":"New Long-Life Concrete Pavements in the Czech Republic","authors":"B. Slánský, V. Šmilauer, Jiří Hlavatý, R. Dvořák","doi":"10.33593/61ba0wvu","DOIUrl":"https://doi.org/10.33593/61ba0wvu","url":null,"abstract":"A jointed plain concrete pavement represents a reliable, historically proven technical solution for highly loaded roads, highways, airports and other industrial surfaces. Excellent resistance to permanent deformations (rutting) and also durability and maintenance costs play key roles in assessing the economic benefits, rehabilitation plans, traffic closures, consumption and recycling of materials. In the history of concrete pavement construction, slow-to-normal hardening Portland cement was used in Czechoslovakia during the 1970s-1980s. The pavements are being replaced after 40-50 years of service, mostly due to vertical slab displacements due to missing dowel bars. However, pavements built after 1996 used rapid hardening cements, resulting in long-term surface cracking and decreased durability. In order to build durable concrete pavements, slower hardening slag-blended binders were designed and tested in the restrained ring shrinkage test and in isothermal calorimetry. Corresponding concretes were tested mainly for the compressive/tensile strength evolution and deicing salt-frost scaling to meet current specifications. The pilot project was executed on a 14 km highway, where a unique temperature-strain monitoring system was installed to provide long-term data from the concrete pavement. A thermo-mechanical coupled model served for data validation, showing a beneficial role of slower hydration kinetics. Continuous monitoring interim results at 24 months have revealed small curling induced by drying and the overall small differential shrinkage of the slab.","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":"130319543","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}
Two-lift concrete pavements use two separate lifts of concrete that are placed in a wet-on-wet process to produce a monolithic structure. Although not new, two-lift concrete pavements are an innovative approach to optimizing the characteristics of each layer and, hence, the overall pavement structure. In 2014, the Federal Highway Administration (FHWA), working in collaboration with the American Association of State Highway and Transportation Officials (AASHTO), selected two-lift composite pavements for funding under the SHRP2 Implementation Assistance Program (IAP). Under that initiative, the design and construction of three composite pavement projects featuring two-lift concrete paving were sponsored. This paper summarizes some of the key design and construction details for each of these three projects, and also provides recommendations on the general applicability and selection of two-lift concrete pavements.
{"title":"Two-Lift Concrete Pavements Constructed Under SHRP2 Project R21 Implementation Effort","authors":"Kurt Smith, Prashant V. Ram, M. Snyder","doi":"10.33593/e7xqgapy","DOIUrl":"https://doi.org/10.33593/e7xqgapy","url":null,"abstract":"Two-lift concrete pavements use two separate lifts of concrete that are placed in a wet-on-wet process to produce a monolithic structure. Although not new, two-lift concrete pavements are an innovative approach to optimizing the characteristics of each layer and, hence, the overall pavement structure. In 2014, the Federal Highway Administration (FHWA), working in collaboration with the American Association of State Highway and Transportation Officials (AASHTO), selected two-lift composite pavements for funding under the SHRP2 Implementation Assistance Program (IAP). Under that initiative, the design and construction of three composite pavement projects featuring two-lift concrete paving were sponsored. This paper summarizes some of the key design and construction details for each of these three projects, and also provides recommendations on the general applicability and selection of two-lift concrete pavements.","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":"130523791","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}
In addition to advances in materials and construction equipment there is a continuing need to ensure adequate skills are available within paving crews. Since 2006 concrete pavement crews and their supervisors in Australia have been required to undertake a mandatory one-day course. Known in industry as the ``Grey Card'' course it was developed jointly by NSW Roads and Maritime Services (RMS) and industry applicable to highway and similar classification roads. It demonstrates a commitment from both sectors to relevant training. Over 180 courses with 3,800 participants have been completed in four States and the Australian Capital Territory. Successful participants are issued with a card that is recognised throughout industry irrespective of changes in an individual's employment. The course is presented by instructors accredited by RMS and drawn from industry professionals who have demonstrated considerable construction experience. There is no other course of this type in Australia. The course has the primary objective of consistently high quality construction. Based on agency Specifications the course sets out the reasons for various construction requirements and site practices necessary to achieve them at paving crew level. Sessions include the basics of making good concrete, setting forms reinforcement and dowels, placing paving and compaction, surface finishing and texturing, curing and protection. This paper sets out the development and presentations of the courses.
{"title":"Industry Training for Concrete Paving Crews in Australia (2006-2020): The “Grey Card” Course","authors":"J. Hodgkinson","doi":"10.33593/zi0gjbke","DOIUrl":"https://doi.org/10.33593/zi0gjbke","url":null,"abstract":"In addition to advances in materials and construction equipment there is a continuing need to ensure adequate skills are available within paving crews. Since 2006 concrete pavement crews and their supervisors in Australia have been required to undertake a mandatory one-day course. Known in industry as the ``Grey Card'' course it was developed jointly by NSW Roads and Maritime Services (RMS) and industry applicable to highway and similar classification roads. It demonstrates a commitment from both sectors to relevant training. Over 180 courses with 3,800 participants have been completed in four States and the Australian Capital Territory. Successful participants are issued with a card that is recognised throughout industry irrespective of changes in an individual's employment. The course is presented by instructors accredited by RMS and drawn from industry professionals who have demonstrated considerable construction experience. There is no other course of this type in Australia. The course has the primary objective of consistently high quality construction. Based on agency Specifications the course sets out the reasons for various construction requirements and site practices necessary to achieve them at paving crew level. Sessions include the basics of making good concrete, setting forms reinforcement and dowels, placing paving and compaction, surface finishing and texturing, curing and protection. This paper sets out the development and presentations of the courses.","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":"128729700","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}
When the design of a concrete pavement is addressed, one of the most important points is to determine which type is the most appropriate to satisfy the requirements. Based on the classification of concrete pavements indicated in ACI 360[1] (Plain concrete, continuously reinforced (bars or welded wire reinforcement), fiber reinforced concrete, shrinkage- compensating and post-tensioned), a series of tests have been developed that allow us to establish a comparison at the level of load capacity. To evaluate the capacity to bending and shear a battery of tests were performed including a beam test and square slab testing. Different systems were designed: Continuously reinforced, steel and macro-synthetic fibers, combined solutions, post-tensioned and shrinkage-compensating concrete pavement. The results show that with an equal amount of steel the load capacity of the continuously reinforced is more than 50% higher than the fiber, and this difference increases when increasing thickness. With equal volume of fiber, the capacity with steel fiber is 25% higher than the synthetic. In Shrinkage-compensating, an expansion of 300 microns/meter was generated, increasing the flexural strength at 0.3 Mpa, improving load capacity and energy absorption. In the post-tensioning system, an effective post-tensioning tension of 2 Mpa was introduced and, consequently, this increase was observed in the appearance of the first crack. In the square slab test the formation and development of the yield lines was observed. Based on the results of the tests and having analyzed the ACI 360 and TR34 to determine the moment capacity of fiber-reinforced concrete and continuously reinforced, it is considered that in the case of continuously reinforced the guides should incorporate a nonlinear method with plasticity considering the ultimate tensile strength of steel. In this way, the comparison between both systems would be closer to reality. Considering only moment capacity and punching shear capacity, it is concluded that solutions with continuous reinforcement (bars or welded wire reinforcement) are more effective for high loads than fibers.
{"title":"COMPARATIVE STUDY THROUGH TESTS OF THE DIFFERENT CONCRETE PAVEMENT SYSTEMS","authors":"Jose M. Lago Carrera, A. Badaoui","doi":"10.33593/m7sz8uu7","DOIUrl":"https://doi.org/10.33593/m7sz8uu7","url":null,"abstract":"When the design of a concrete pavement is addressed, one of the most important points is to determine which type is the most appropriate to satisfy the requirements. Based on the classification of concrete pavements indicated in ACI 360[1] (Plain concrete, continuously reinforced (bars or welded wire reinforcement), fiber reinforced concrete, shrinkage- compensating and post-tensioned), a series of tests have been developed that allow us to establish a comparison at the level of load capacity. To evaluate the capacity to bending and shear a battery of tests were performed including a beam test and square slab testing. Different systems were designed: Continuously reinforced, steel and macro-synthetic fibers, combined solutions, post-tensioned and shrinkage-compensating concrete pavement. The results show that with an equal amount of steel the load capacity of the continuously reinforced is more than 50% higher than the fiber, and this difference increases when increasing thickness. With equal volume of fiber, the capacity with steel fiber is 25% higher than the synthetic. In Shrinkage-compensating, an expansion of 300 microns/meter was generated, increasing the flexural strength at 0.3 Mpa, improving load capacity and energy absorption. In the post-tensioning system, an effective post-tensioning tension of 2 Mpa was introduced and, consequently, this increase was observed in the appearance of the first crack. In the square slab test the formation and development of the yield lines was observed. Based on the results of the tests and having analyzed the ACI 360 and TR34 to determine the moment capacity of fiber-reinforced concrete and continuously reinforced, it is considered that in the case of continuously reinforced the guides should incorporate a nonlinear method with plasticity considering the ultimate tensile strength of steel. In this way, the comparison between both systems would be closer to reality. Considering only moment capacity and punching shear capacity, it is concluded that solutions with continuous reinforcement (bars or welded wire reinforcement) are more effective for high loads than fibers.","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":"133686816","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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