The document discusses the history and evolution of asphalt binder specifications. Originally, naturally occurring asphalts from lakes were used in early road construction. Demand later exceeded the natural supply, leading to use of petroleum-derived asphalts. Early specifications focused on properties like consistency, penetration, flash point, and solubility. Over time, specifications evolved to incorporate viscosity grading based on fundamental rheological properties and accounting for aging. Viscosity grading allows specification of asphalt binders for different climates and performance expectations.
CON 123 Session 10 - Other Cementitious Materialsalpenaccedu
This document discusses other cementitious materials that can be used in concrete, including natural pozzolans like volcanic tuffs and diatomaceous earth, and manufactured pozzolans such as metakaolin and rice husk ash. Using these pozzolanic materials provides benefits to concrete like low permeability, high strength, sulfate and alkali-silica resistance, and they react to form calcium silicate hydrate. Manufactured pozzolans include heat-treated kaolin clay and rice husk ash combustion ash. Calcined clay and shale can also reduce alkali-silica reactivity. Several relevant websites are provided.
Powerpoint for persepolis historical backgroundtaichung
Iran has a long history, with the earliest settlers being Aryans around 1500 BC. The Persian Empire dominated the region for centuries until being conquered by Alexander the Great. Modern Iran was shaped by dynasties like the Qajars and Pahlavis; Reza Shah sought to modernize the country in the early 20th century. However, his son Mohammad Reza Shah grew increasingly authoritarian, facing opposition until the 1979 Islamic Revolution overthrew the monarchy and established an Islamic republic led by Ayatollah Khomeini.
The document discusses the history and evolution of asphalt binder specifications. Early specifications focused on consistency and graded binders based on penetration testing. Later, specifications incorporated viscosity grading which characterizes binders across a range of temperatures relevant to mixing and compaction. Current performance-based specifications further consider aging characteristics by testing rolled thin film oven aged residues. Viscosity grading provides more information on asphalt properties and performance compared to penetration grading. Specifications have evolved with technological advances to better ensure desirable asphalt characteristics for pavement performance.
03-Properties of Asphalt Traditional ( Highway and Airport Engineering Dr. Sh...Hossam Shafiq I
This document discusses the properties and temperature susceptibility of asphalt binders. It describes how binder performance is affected by temperature and loading rate. The stiffness and viscosity of asphalt changes drastically with temperature, going from solid to fluid. The document outlines various test methods and specifications used to characterize and grade asphalt binders, including penetration grades, viscosity grades, and grades based on viscosity after aging. It compares the advantages and disadvantages of different grading systems and specifications.
Presentation on asphalt binders by Bob Humer, Asphalt Institute, delivered at the California Asphalt Pavement Association (CalAPA) Spring Asphalt Pavement Conference April 25-26, 2018 in Ontario, CA.
The document discusses road pavement materials and construction. It describes the main materials used which are aggregates and asphalt or cement as binders. It provides details on types of pavement construction including flexible pavement using asphalt and rigid pavement using cement. It also discusses specifications and testing of aggregate materials and asphalt types used in pavement construction.
The document discusses materials used in bituminous bound pavements. It describes aggregates, types of bitumen including penetration grade bitumens and cutbacks, and asphalt concrete. It also covers mix design methods like Marshall and Hveem, and construction processes for asphalt concrete pavements and surface dressings. Laboratory tests discussed include penetration, ductility, viscosity, and aggregate shape tests.
This document provides information about slag cement and its use in concrete applications. It discusses the production of slag cement, its chemical and physical properties compared to portland cement, benefits of using slag cement such as improved workability, strength, and durability. It provides examples of projects that have used slag cement concrete mixtures with replacement rates ranging from 20-50% and achieved strength gains. Contact information is also provided for follow up questions.
CON 123 Session 10 - Other Cementitious Materialsalpenaccedu
This document discusses other cementitious materials that can be used in concrete, including natural pozzolans like volcanic tuffs and diatomaceous earth, and manufactured pozzolans such as metakaolin and rice husk ash. Using these pozzolanic materials provides benefits to concrete like low permeability, high strength, sulfate and alkali-silica resistance, and they react to form calcium silicate hydrate. Manufactured pozzolans include heat-treated kaolin clay and rice husk ash combustion ash. Calcined clay and shale can also reduce alkali-silica reactivity. Several relevant websites are provided.
Powerpoint for persepolis historical backgroundtaichung
Iran has a long history, with the earliest settlers being Aryans around 1500 BC. The Persian Empire dominated the region for centuries until being conquered by Alexander the Great. Modern Iran was shaped by dynasties like the Qajars and Pahlavis; Reza Shah sought to modernize the country in the early 20th century. However, his son Mohammad Reza Shah grew increasingly authoritarian, facing opposition until the 1979 Islamic Revolution overthrew the monarchy and established an Islamic republic led by Ayatollah Khomeini.
The document discusses the history and evolution of asphalt binder specifications. Early specifications focused on consistency and graded binders based on penetration testing. Later, specifications incorporated viscosity grading which characterizes binders across a range of temperatures relevant to mixing and compaction. Current performance-based specifications further consider aging characteristics by testing rolled thin film oven aged residues. Viscosity grading provides more information on asphalt properties and performance compared to penetration grading. Specifications have evolved with technological advances to better ensure desirable asphalt characteristics for pavement performance.
03-Properties of Asphalt Traditional ( Highway and Airport Engineering Dr. Sh...Hossam Shafiq I
This document discusses the properties and temperature susceptibility of asphalt binders. It describes how binder performance is affected by temperature and loading rate. The stiffness and viscosity of asphalt changes drastically with temperature, going from solid to fluid. The document outlines various test methods and specifications used to characterize and grade asphalt binders, including penetration grades, viscosity grades, and grades based on viscosity after aging. It compares the advantages and disadvantages of different grading systems and specifications.
Presentation on asphalt binders by Bob Humer, Asphalt Institute, delivered at the California Asphalt Pavement Association (CalAPA) Spring Asphalt Pavement Conference April 25-26, 2018 in Ontario, CA.
The document discusses road pavement materials and construction. It describes the main materials used which are aggregates and asphalt or cement as binders. It provides details on types of pavement construction including flexible pavement using asphalt and rigid pavement using cement. It also discusses specifications and testing of aggregate materials and asphalt types used in pavement construction.
The document discusses materials used in bituminous bound pavements. It describes aggregates, types of bitumen including penetration grade bitumens and cutbacks, and asphalt concrete. It also covers mix design methods like Marshall and Hveem, and construction processes for asphalt concrete pavements and surface dressings. Laboratory tests discussed include penetration, ductility, viscosity, and aggregate shape tests.
This document provides information about slag cement and its use in concrete applications. It discusses the production of slag cement, its chemical and physical properties compared to portland cement, benefits of using slag cement such as improved workability, strength, and durability. It provides examples of projects that have used slag cement concrete mixtures with replacement rates ranging from 20-50% and achieved strength gains. Contact information is also provided for follow up questions.
This document discusses asphalt binder characterization and specifications. It describes traditional tests like penetration, softening point, and viscosity tests. It also describes performance grade tests from the Superpave system like rotational viscometer, dynamic shear rheometer, bending beam rheometer, and direct tension tests. The document discusses classifying asphalt cement based on penetration, viscosity, aged viscosity, and performance. It also explains viscosity graded and viscosity after aging graded specifications, describing specifications for grades like AC and AR.
This document discusses different methods for grading bituminous binders, including penetration grading, viscosity grading, and performance grading. Penetration grading uses the penetration test results at 25°C to specify grades. Viscosity grading specifies grades based on viscosity measurements at 60°C and 135°C. Performance grading assigns grades based on the temperature ranges where the binder is expected to perform satisfactorily against rutting, fatigue cracking, and low-temperature cracking. The document also covers specifications, advantages and disadvantages of each grading method, and definitions and measurement of viscosity and its importance in characterizing bitumen properties.
This document outlines the quality assurance plan for materials to be used on the Golden Panorama Luxury Apartments project in Bangalore. It lists 36 materials that will be tested, including cement, aggregates, bricks, steel, waterproofing membranes, tiles, and pipes. For each material, it specifies the tests to be conducted according to Indian codes, the contractor's responsibilities for testing frequency, and the project management consultant's roles in reviewing test reports and certificates. The overall goal is to ensure that all materials meet the necessary quality standards through a rigorous testing program.
The document provides information on the chemical composition and typical oxide composition percentages of raw materials used to make cement. It states that lime (CaO) ranges from 60-65% and controls strength and soundness. Silica (SiO2) ranges from 17-25% and excess causes slow setting. Alumina (Al2O3) ranges from 3-8% and is responsible for quick setting, with excess lowering strength. Iron oxide (Fe2O3) ranges from 0.5-6% and gives color and helps fuse ingredients. Magnesia (MgO) ranges from 0.1-4% and gives color and hardness. Soda and potash (Na2O and K2O)
HIGHWAY CONSTRUCTION MATERIAL AND PRACTICERowingGhosh
HIGHWAY CONSTRUCTION MATERIAL & PRACTICE
Age hardening is a result of a number of factors, the principal ones being
Oxidation. The reaction of oxygen with the asphalt binder.
Volatilization. The evaporation of the lighter constituents of asphalt binder. It is primarily a function of temperature and occurs principally during HMA production.
Polymerization. The combining of like molecules to form larger molecules. These larger molecules are thought to cause a progressive hardening.
This document discusses sustainability in road construction. It notes that road construction requires large amounts of materials like aggregates and fuel for transportation and production, which causes high energy consumption and emissions. It also causes issues with waste generation from old pavements. The document then discusses different techniques for pavement maintenance and rehabilitation like reconstruction, overlaying, and recycling. It focuses on full depth recycling (FDR) techniques, providing details on the suitability of roads, types of binders used, the construction process, and mix design process for FDR using cement or bitumen stabilization. FDR can help reduce material consumption and waste generation compared to other techniques.
Ceramic Epoxy Presentation -- Induron Protective CoatingsIntermark Group
This document summarizes Induron Protective Coatings, a company that produces ceramic epoxy coatings founded in 1947. It introduces their new line of ceramic epoxy coatings that provide corrosion protection for water tanks, pipes, and other industrial structures. The coatings are 100% solids, with no solvents, VOCs, or HAPs. They offer benefits like self-healing of pinholes, high film builds up to 80 mils in one coat, very low permeability, and inhibition of microbiological growth. Performance testing results on various coatings are provided. Examples of application projects are shown and benefits of single coat application discussed.
This document summarizes a presentation on cementing for well isolation. It discusses the importance of cementing for preventing flow to the surface and maintaining well integrity. Proper planning and execution of cementing operations is important to ensure zonal isolation for the life of the well. Key factors discussed include mud displacement, cement placement, temperature effects, and integrated mud and cement design.
CON 124 - Session 6 - Concrete Durabilityalpenaccedu
This document discusses concrete durability, focusing on alkali-silica reaction (ASR) and the effect of water-to-cement ratio. It describes ASR as a reaction between alkalies in cement and certain aggregates, causing expansion and cracking. Factors contributing to ASR are discussed, along with testing and mitigation methods. Lower water-to-cement ratios produce stronger, more durable concrete by reducing permeability. Various tests are described for evaluating ASR and the effectiveness of supplementary cementitious materials in mitigating it.
Project Execution Plan for Muscat Runway Construction, OmanDavid H Moloney
The document is a project execution plan for runway construction at an airport. It includes 3 sentences:
It outlines the sequence of work activities, resources needed like quarries for aggregate production, and methods for different construction tasks such as installing drainage culverts, constructing precast elements, and laying crushed aggregate base courses, asphalt, and concrete pavement. Precise control of levels, grades, and joint patterns is described for pavement construction along with compaction methods and testing. The plan provides details on plant and equipment used, output rates expected, and control of mix properties and temperatures during paving.
MbaMsc Ing CARLOS IVER SARAVIA VIDAL- USFX_ 01 SEP 2020_WELL INTERVENTIOSN & ...Javier F. Via Giglio
This document provides information about an expert in well interventions and production for conventional and unconventional reservoirs named Carlos Saravia. It includes Carlos' background and qualifications, as well as topics he covers in presentations related to sand control, acidizing, frac packing, and calculations for well completion technologies. The document contains examples and case studies to illustrate different solutions for issues like sand production and fines migration.
This document provides information on concrete technology and the ingredients and manufacturing process of cement. It discusses the key components of cement including tricalcium silicate, dicalcium silicate, tricalcium aluminate, and tetracalcium aluminoferrite. It also describes the testing methods for cement such as consistency, setting time, soundness, and compressive/tensile strength tests. Different types of cement are mentioned like rapid hardening, low heat, sulphate resisting, and Portland slag cement.
Rtc seminar presentation - s1 - m ansar v - r02MOHAMMADANSAR12
This study examined the effect of various grades of solution styrene butadiene rubber (SSBR) on the performance of passenger car tire tread compounds. Five compounds were prepared using different SSBR grades that varied in styrene and vinyl content. Testing showed that Compound C, which used a SSBR grade with 40.2% styrene and 43.2% vinyl content, demonstrated the best balance of properties within the "magic triangle" of wet traction, dry traction, and rolling resistance. Compound C showed optimized wet traction performance along with comparable rolling resistance and abrasion resistance to the other compounds. The use of SSBR in tire tread compounds was found to provide better traction properties and rolling resistance compared to other rubbers.
Presentation on Cement -07.06.2022.pptxMuni Raja B
The document provides information on different types of cement. It discusses the raw materials, manufacturing processes, and chemical composition of ordinary Portland cement. It also explains the role of different compounds like C3S, C2S, C3A, and C4AF in the strength development and hydration of cement. Finally, it summarizes the characteristics and applications of various specialized cements like rapid hardening cement, sulphate resisting cement, low heat cement, oil well cement, and others.
The document discusses Superpave mix design, which is a performance-based method for designing asphalt concrete mixtures. Some key points:
- Superpave uses the gyratory compactor to simulate field compaction of mixtures, allowing for evaluation of density during the design process.
- The design process involves 4 steps: selecting materials based on traffic and climate conditions, designing the aggregate structure, determining the optimum asphalt binder content, and evaluating moisture susceptibility.
- Key evaluation points on the gyratory compaction curve are Ninitial, Ndesign, and Nmax, which control compactability, expected field density, and maximum allowed density.
- Design traffic level determines the number
This document discusses materials used in highway construction, including aggregates, bitumen, asphalt, tar, cement, and steel reinforcement. It describes aggregates as a coarse particulate material used in construction that serves as reinforcement. It also summarizes different tests conducted on materials, such as aggregate impact value, polished stone value, and ductility tests. Finally, it provides an overview of asphalt mix design, noting its objectives are to determine a cost-effective blend of aggregates and binder that meets specifications and provides sufficient stability, voids, workability, and skid resistance.
This document discusses mix design and material testing for slurry seal and micro surfacing systems. It provides details on the components of slurry seal and micro surfacing mixes, including aggregate, asphalt emulsion, water, mineral filler, and chemical additives. It also summarizes specifications and purposes of various tests conducted on the materials and mixtures, such as tests for emulsion viscosity and residue, aggregate sand equivalence and gradation, and mix compatibility and performance. The document emphasizes that mix designs provide an indication that quality materials can produce a working system, but contractors must execute the work properly to achieve superior results.
The document discusses the cement manufacturing process. It begins with a brief history of cement and then describes the main steps:
1) Raw materials like limestone and clay are quarries and ground.
2) The raw materials are preheated, dried, and calcined in a kiln to drive off carbon dioxide and water.
3) The remaining material is sintered at high temperatures to form nodules of clinker containing tricalcium silicate, dicalcium silicate, tricalcium aluminate, and tetracalcium aluminoferrite.
4) The clinker is cooled and ground into a fine powder to produce cement.
This document provides an overview of sand casting processes. It discusses the key steps which include pattern making, molding sand properties and testing, core making, melting furnaces, casting defects and inspection methods. The main molding processes covered are green sand molding and dry sand molding. Common casting defects like blowholes and surface cracks are addressed. Non-destructive testing methods for inspecting castings such as magnetic particle, dye penetrant, radiography and ultrasonic testing are also summarized.
This document discusses the fundamentals of rheology and describes various types of rheometers used to measure the rheological properties of asphalt binders. It explains that rheology is the study of flow and deformation and introduces constitutive relationships between force and deformation. It then describes different types of rheometers, including shear rheometers that apply drag or pressure-driven flows, and other rheometers that measure stiffness and strength through bending beam or direct tension tests. Specific examples of equipment are also shown, such as concentric cylinder and parallel plate shear rheometers, a bending beam rheometer, and a direct tension testing device.
The document discusses Superpave asphalt binder specifications. It provides sources of information on Superpave specifications and describes how the performance grade specification system works based on climate. The performance grade takes into account the average 7-day maximum pavement temperature and the 1-day minimum pavement temperature. It then outlines how the Superpave specification addresses key distresses like permanent deformation, fatigue cracking, and low temperature cracking through test requirements on properties like stiffness and viscosity.
This document discusses asphalt binder characterization and specifications. It describes traditional tests like penetration, softening point, and viscosity tests. It also describes performance grade tests from the Superpave system like rotational viscometer, dynamic shear rheometer, bending beam rheometer, and direct tension tests. The document discusses classifying asphalt cement based on penetration, viscosity, aged viscosity, and performance. It also explains viscosity graded and viscosity after aging graded specifications, describing specifications for grades like AC and AR.
This document discusses different methods for grading bituminous binders, including penetration grading, viscosity grading, and performance grading. Penetration grading uses the penetration test results at 25°C to specify grades. Viscosity grading specifies grades based on viscosity measurements at 60°C and 135°C. Performance grading assigns grades based on the temperature ranges where the binder is expected to perform satisfactorily against rutting, fatigue cracking, and low-temperature cracking. The document also covers specifications, advantages and disadvantages of each grading method, and definitions and measurement of viscosity and its importance in characterizing bitumen properties.
This document outlines the quality assurance plan for materials to be used on the Golden Panorama Luxury Apartments project in Bangalore. It lists 36 materials that will be tested, including cement, aggregates, bricks, steel, waterproofing membranes, tiles, and pipes. For each material, it specifies the tests to be conducted according to Indian codes, the contractor's responsibilities for testing frequency, and the project management consultant's roles in reviewing test reports and certificates. The overall goal is to ensure that all materials meet the necessary quality standards through a rigorous testing program.
The document provides information on the chemical composition and typical oxide composition percentages of raw materials used to make cement. It states that lime (CaO) ranges from 60-65% and controls strength and soundness. Silica (SiO2) ranges from 17-25% and excess causes slow setting. Alumina (Al2O3) ranges from 3-8% and is responsible for quick setting, with excess lowering strength. Iron oxide (Fe2O3) ranges from 0.5-6% and gives color and helps fuse ingredients. Magnesia (MgO) ranges from 0.1-4% and gives color and hardness. Soda and potash (Na2O and K2O)
HIGHWAY CONSTRUCTION MATERIAL AND PRACTICERowingGhosh
HIGHWAY CONSTRUCTION MATERIAL & PRACTICE
Age hardening is a result of a number of factors, the principal ones being
Oxidation. The reaction of oxygen with the asphalt binder.
Volatilization. The evaporation of the lighter constituents of asphalt binder. It is primarily a function of temperature and occurs principally during HMA production.
Polymerization. The combining of like molecules to form larger molecules. These larger molecules are thought to cause a progressive hardening.
This document discusses sustainability in road construction. It notes that road construction requires large amounts of materials like aggregates and fuel for transportation and production, which causes high energy consumption and emissions. It also causes issues with waste generation from old pavements. The document then discusses different techniques for pavement maintenance and rehabilitation like reconstruction, overlaying, and recycling. It focuses on full depth recycling (FDR) techniques, providing details on the suitability of roads, types of binders used, the construction process, and mix design process for FDR using cement or bitumen stabilization. FDR can help reduce material consumption and waste generation compared to other techniques.
Ceramic Epoxy Presentation -- Induron Protective CoatingsIntermark Group
This document summarizes Induron Protective Coatings, a company that produces ceramic epoxy coatings founded in 1947. It introduces their new line of ceramic epoxy coatings that provide corrosion protection for water tanks, pipes, and other industrial structures. The coatings are 100% solids, with no solvents, VOCs, or HAPs. They offer benefits like self-healing of pinholes, high film builds up to 80 mils in one coat, very low permeability, and inhibition of microbiological growth. Performance testing results on various coatings are provided. Examples of application projects are shown and benefits of single coat application discussed.
This document summarizes a presentation on cementing for well isolation. It discusses the importance of cementing for preventing flow to the surface and maintaining well integrity. Proper planning and execution of cementing operations is important to ensure zonal isolation for the life of the well. Key factors discussed include mud displacement, cement placement, temperature effects, and integrated mud and cement design.
CON 124 - Session 6 - Concrete Durabilityalpenaccedu
This document discusses concrete durability, focusing on alkali-silica reaction (ASR) and the effect of water-to-cement ratio. It describes ASR as a reaction between alkalies in cement and certain aggregates, causing expansion and cracking. Factors contributing to ASR are discussed, along with testing and mitigation methods. Lower water-to-cement ratios produce stronger, more durable concrete by reducing permeability. Various tests are described for evaluating ASR and the effectiveness of supplementary cementitious materials in mitigating it.
Project Execution Plan for Muscat Runway Construction, OmanDavid H Moloney
The document is a project execution plan for runway construction at an airport. It includes 3 sentences:
It outlines the sequence of work activities, resources needed like quarries for aggregate production, and methods for different construction tasks such as installing drainage culverts, constructing precast elements, and laying crushed aggregate base courses, asphalt, and concrete pavement. Precise control of levels, grades, and joint patterns is described for pavement construction along with compaction methods and testing. The plan provides details on plant and equipment used, output rates expected, and control of mix properties and temperatures during paving.
MbaMsc Ing CARLOS IVER SARAVIA VIDAL- USFX_ 01 SEP 2020_WELL INTERVENTIOSN & ...Javier F. Via Giglio
This document provides information about an expert in well interventions and production for conventional and unconventional reservoirs named Carlos Saravia. It includes Carlos' background and qualifications, as well as topics he covers in presentations related to sand control, acidizing, frac packing, and calculations for well completion technologies. The document contains examples and case studies to illustrate different solutions for issues like sand production and fines migration.
This document provides information on concrete technology and the ingredients and manufacturing process of cement. It discusses the key components of cement including tricalcium silicate, dicalcium silicate, tricalcium aluminate, and tetracalcium aluminoferrite. It also describes the testing methods for cement such as consistency, setting time, soundness, and compressive/tensile strength tests. Different types of cement are mentioned like rapid hardening, low heat, sulphate resisting, and Portland slag cement.
Rtc seminar presentation - s1 - m ansar v - r02MOHAMMADANSAR12
This study examined the effect of various grades of solution styrene butadiene rubber (SSBR) on the performance of passenger car tire tread compounds. Five compounds were prepared using different SSBR grades that varied in styrene and vinyl content. Testing showed that Compound C, which used a SSBR grade with 40.2% styrene and 43.2% vinyl content, demonstrated the best balance of properties within the "magic triangle" of wet traction, dry traction, and rolling resistance. Compound C showed optimized wet traction performance along with comparable rolling resistance and abrasion resistance to the other compounds. The use of SSBR in tire tread compounds was found to provide better traction properties and rolling resistance compared to other rubbers.
Presentation on Cement -07.06.2022.pptxMuni Raja B
The document provides information on different types of cement. It discusses the raw materials, manufacturing processes, and chemical composition of ordinary Portland cement. It also explains the role of different compounds like C3S, C2S, C3A, and C4AF in the strength development and hydration of cement. Finally, it summarizes the characteristics and applications of various specialized cements like rapid hardening cement, sulphate resisting cement, low heat cement, oil well cement, and others.
The document discusses Superpave mix design, which is a performance-based method for designing asphalt concrete mixtures. Some key points:
- Superpave uses the gyratory compactor to simulate field compaction of mixtures, allowing for evaluation of density during the design process.
- The design process involves 4 steps: selecting materials based on traffic and climate conditions, designing the aggregate structure, determining the optimum asphalt binder content, and evaluating moisture susceptibility.
- Key evaluation points on the gyratory compaction curve are Ninitial, Ndesign, and Nmax, which control compactability, expected field density, and maximum allowed density.
- Design traffic level determines the number
This document discusses materials used in highway construction, including aggregates, bitumen, asphalt, tar, cement, and steel reinforcement. It describes aggregates as a coarse particulate material used in construction that serves as reinforcement. It also summarizes different tests conducted on materials, such as aggregate impact value, polished stone value, and ductility tests. Finally, it provides an overview of asphalt mix design, noting its objectives are to determine a cost-effective blend of aggregates and binder that meets specifications and provides sufficient stability, voids, workability, and skid resistance.
This document discusses mix design and material testing for slurry seal and micro surfacing systems. It provides details on the components of slurry seal and micro surfacing mixes, including aggregate, asphalt emulsion, water, mineral filler, and chemical additives. It also summarizes specifications and purposes of various tests conducted on the materials and mixtures, such as tests for emulsion viscosity and residue, aggregate sand equivalence and gradation, and mix compatibility and performance. The document emphasizes that mix designs provide an indication that quality materials can produce a working system, but contractors must execute the work properly to achieve superior results.
The document discusses the cement manufacturing process. It begins with a brief history of cement and then describes the main steps:
1) Raw materials like limestone and clay are quarries and ground.
2) The raw materials are preheated, dried, and calcined in a kiln to drive off carbon dioxide and water.
3) The remaining material is sintered at high temperatures to form nodules of clinker containing tricalcium silicate, dicalcium silicate, tricalcium aluminate, and tetracalcium aluminoferrite.
4) The clinker is cooled and ground into a fine powder to produce cement.
This document provides an overview of sand casting processes. It discusses the key steps which include pattern making, molding sand properties and testing, core making, melting furnaces, casting defects and inspection methods. The main molding processes covered are green sand molding and dry sand molding. Common casting defects like blowholes and surface cracks are addressed. Non-destructive testing methods for inspecting castings such as magnetic particle, dye penetrant, radiography and ultrasonic testing are also summarized.
This document discusses the fundamentals of rheology and describes various types of rheometers used to measure the rheological properties of asphalt binders. It explains that rheology is the study of flow and deformation and introduces constitutive relationships between force and deformation. It then describes different types of rheometers, including shear rheometers that apply drag or pressure-driven flows, and other rheometers that measure stiffness and strength through bending beam or direct tension tests. Specific examples of equipment are also shown, such as concentric cylinder and parallel plate shear rheometers, a bending beam rheometer, and a direct tension testing device.
The document discusses Superpave asphalt binder specifications. It provides sources of information on Superpave specifications and describes how the performance grade specification system works based on climate. The performance grade takes into account the average 7-day maximum pavement temperature and the 1-day minimum pavement temperature. It then outlines how the Superpave specification addresses key distresses like permanent deformation, fatigue cracking, and low temperature cracking through test requirements on properties like stiffness and viscosity.
The document discusses the Superpave performance graded specification for asphalt binders. The specification grades asphalt binders based on the climate and expected pavement temperatures. A variety of tests are used to evaluate the binder properties related to different distresses at different temperatures. The rotational viscosity test evaluates workability at construction temperatures. The dynamic shear rheometer test evaluates rutting resistance at high in-service temperatures after both short-term aging from mixing and long-term aging. The bending beam rheometer and direct tension tests evaluate stiffness and strength respectively at low in-service temperatures. Conditioning such as short-term aging with the rolling thin film oven test and long-term aging with the pressure aging vessel better simulate
The document discusses different types and uses of asphalt binders. It describes how asphalt binder is produced from petroleum crude oil through refining processes like solvent deasphalting and residuum oil supercritical extraction. These processes break down the crude oil into components that are blended to produce asphalt binders of desired properties. The asphalt binders are then used to manufacture hot mix asphalt for paving roads through batch and continuous mix drum plants. Other asphalt products discussed include cutback asphalts and emulsions, along with their compositions and uses.
This document discusses modified asphalt binders, which are used to improve the performance of asphalt pavements. Modifiers such as polymers and fillers are added to asphalt binders to increase rutting resistance at warm temperatures and inhibit cracking from traffic and environmental stresses. The document describes different types of modifiers and provides examples of polymeric modifiers. It also discusses traditional testing methods for modified binders and uses microscopy images to illustrate how polymers interact within asphalt binders.
This document discusses techniques for rehabilitating and maintaining asphalt overlays on concrete pavements, including crack and seat, break and seat, rubblization, and saw and seal. Crack and seat and break and seat involve fracturing concrete slabs to shorten their length and allow for interlocking of pieces. Rubblization involves fracturing concrete into pieces smaller than 9 inches to prevent reflection cracking in overlays. Saw and sealing joints is used to control the rate of deterioration of reflection cracks.
The document discusses various aspects of asphalt pavement rehabilitation and maintenance using hot mix asphalt overlays. It covers topics such as bituminous patching, surface leveling, cold milling, crack sealing, subsurface drainage, reflection cracking control methods, recycling existing pavement, pavement widening, shoulder rehabilitation, and design of overlays along projects. The key steps for an effective overlay project involve examining preoverlay repairs, subsurface drainage improvements, and methods for controlling reflection cracking from the existing pavement.
This document discusses hot mix asphalt (HMA) overlays for rehabilitating flexible and rigid pavements. It defines functional and structural overlays, and describes how they are used to address surface defects versus structural defects. The rehabilitation process and factors considered for overlay design like pre-overlay repair, materials selection, and traffic loads are also summarized. Thick and thin overlays as well as reconstruction are presented as options to correct deficiencies.
This document discusses moisture sensitivity in HMA (hot mix asphalt). It describes several reasons for moisture damage including loss of cohesion in the asphalt binder, loss of adhesion between the binder and aggregate, and degradation of the aggregate. It also discusses factors that influence moisture sensitivity related to the aggregate properties, asphalt binder properties, HMA mix properties, and weather conditions during construction. Methods for adding antistripping additives like liquid antistrips or lime are presented, as well as several tests for evaluating moisture sensitivity like the boiling water test or freeze-thaw pedestal test.
This document discusses thermal cracking in asphalt pavements. Thermal cracking occurs when temperature decreases cause the pavement to contract and develop tensile stresses that can exceed the material strength. Three factors influence thermal cracking: low pavement surface temperature, cooling rate, and pavement age. The Thermal Stress Restrained Specimen Test (TSRST) directly measures the development of thermal stresses during cooling and identifies the fracture temperature and strength. Test results show lower air voids and some aggregate types can increase fracture temperature and strength. Desirable material properties to resist thermal cracking include low-temperature asphalt binder viscosity and aggregate with high abrasion resistance and low freeze-thaw loss. Pavement structure characteristics like thickness, base
This document discusses test methods for characterizing permanent deformation in hot mix asphalt (HMA). It describes loaded wheel testers like the Asphalt Pavement Analyzer (APA), Hamburg Wheel Tracker, and Purdue Wheel Tracker that apply cyclic wheel loads to HMA samples. Terms related to permanent deformation testing like creep, repeated loading, and dynamic loading are defined. Parameters for different loaded wheel testers and typical APA test results are shown. The document also briefly mentions the gyratory shear compactor, simple shear tester, and uniaxial and triaxial testing for HMA characterization.
This document discusses fatigue cracking in asphalt pavements. It describes how fatigue cracking can start from the bottom of the pavement layer and work its way up, or can start at the top edges due to tire-pavement interactions. Common fatigue testing methods are described, including flexural beam testing where failure is defined as 50% loss of stiffness. Test results depend on whether constant stress or constant strain is used. Other testing methods like cantilevered beam and diametral are also mentioned. Advanced topics covered include notched beam testing, dissipated energy calculations, and models for predicting fatigue life from binder and mix properties.
Stiffness measurements of hot mix asphalt (HMA) mixtures are important for predicting pavement performance and stresses/strains. Various methods exist to measure stiffness through axial, diametral, flexural, or shear testing under repeated or dynamic loading. Stiffness decreases with increasing temperature and air voids, and decreasing asphalt content. Proper characterization of HMA stiffness at different conditions is essential for evaluating fatigue cracking and permanent deformation.
This document discusses typical distresses that can occur in flexible asphalt pavements and their causes. It describes various types of cracking like fatigue cracking, thermal cracking, block cracking, longitudinal cracking, reflection cracking, as well as other distresses such as rutting, corrugations, slippage, stripping, raveling, reduced skid resistance, roughness, and swelling from frost. Each distress is explained in terms of how it manifests visually and what factors can contribute to its development, such as heavy traffic loads, inadequate drainage, mix design issues, or temperature susceptibility of the asphalt binder. The document provides an overview of the main distresses that can affect flexible pavements and their underlying mechanisms.
This document discusses quality control and quality assurance control charts. It explains that control charts can be used to monitor processes and detect variation, including chance causes and assignable causes. Control charts have benefits like early detection of issues, establishing process capability, and providing a permanent record of quality. Examples are provided of how to construct X-bar and R control charts and interpret the results to determine whether a process is in statistical control.
This document discusses quality control and quality assurance procedures for obtaining representative samples of asphalt mixtures and their components. It describes how to properly sample materials at different stages, including at plants, trucks, and roadways. The key aspects covered are sampling locations and techniques, sample size requirements, handling and storage of samples, and potential issues that can arise from improper sampling procedures like segregation. Maintaining representative samples is important for ensuring accurate test results and mixture quality.
This document discusses quality control and quality assurance sampling procedures for construction projects. It addresses requirements for a sampling program, including frequency, location, and size of samples. Different types of sampling are described, such as judgment, quota, systematic, stratified, and random sampling. Random sampling is preferable to avoid bias, and it is best to use random number tables to select sample locations. Stratified random sampling involves dividing a construction site into sublots for sampling. The document provides an example of how to use random numbers to select sample locations within sublots for both roadway and hot mix asphalt plant sampling.
This document discusses basic concepts of statistics as they relate to quality control and quality assurance in construction. It explains that variability is inherent in all materials and processes, but can be controlled. Sources of variability include sampling, testing, materials, and construction methods. The goal of quality control/quality assurance is to reduce variability as much as possible by addressing these sources. Key statistical terms discussed include mean, median, range, variance, precision, accuracy, and bias. Frequency histograms are presented as a tool to visualize variability in data.
This document provides an overview of quality control and quality assurance procedures for construction projects. It discusses different types of specifications like proprietary, method, and end result specifications. It also covers topics like process control, acceptance testing, sampling procedures, warranties, and reasons for sampling materials. The overall purpose is to introduce fundamental concepts regarding specifications, testing, and quality assurance/quality control as they relate to construction quality management.
The document discusses acceptance and compliance procedures for hot mix asphalt. It explains how specification limits are set using typical industry standard deviations and allowing three standard deviations from the target value. It also introduces the concept of percent within limits (PWL) which is used to determine payment based on both the accuracy and precision of the test results. The PWL is calculated using quality indices determined from the test average, standard deviation, and specification limits. Examples are provided to demonstrate calculating quality indices and determining the PWL.
1. Senior/Graduate
HMA Course
Asphalt Binders
Background
History of Specifications
Asphalt Binders History and Background 1
2. Background
First US Hot Mix Asphalt
(HMA) constructed in
1870’s
– Pennsylvania Ave.
– Used naturally
occurring asphalt
binders from surface of
lake on Island of
Trinidad
Two sources
– Island of Trinadad
– Bermudez, Venezuela
5. Background
Each lake asphalt source very consistent
– Used solubility test to determine source
» Insolubles differed substantially between
sources
Demand for paved roads exceeded the supply of
lake asphalts in late 1800’s
– Led to use of petroleum asphalts binders
Asphalt Binder History and Background 5
7. Petroleum-Based Asphalt Binders
Asphalt binder is waste product from refinery
processing of crude oil
– Sometimes called the “bottom of the barrel”
Properties depend on:
– Refinery operations
– Composition crude source-dependent
Gasoline
Kerosene
Lt. Gas Oil Barrel of Crude Oil
Diesel
Motor Oils
Asphalt
Asphalt Binder History and Background 7
8. Purchasing of Asphalt Binders
Need to be able to specify desirable
characteristics
“Desirable characteristics” have evolved
over time and with increasing
technological advances
Purchasing requires specifications
Asphalt Binder History and Background 8
9. Early Specifications
Lake Asphalts
– Appearance
– Solubility in carbon disulfide
Petroleum asphalt binders (early 1900’s)
– Consistency
» Chewing
» Penetration machine
Measure consistency
Asphalt Binder History and Background 9
19. Advantages
Grades asphalt binders near average in-
service temp.
Fast
Can be used in field labs
Low capital costs
Precision well established
Temp. susceptibility can be determined
Asphalt Binder History and Background 19
20. Disadvantages
Empirical test
Shear rate
– High
– Variable
Mixing and compaction temp. information not
available
Similar penetrations at 25C (77F) do not
reflect wide differences in asphalts
Asphalt Binder History and Background 20
22. Definition
Viscosity: the ratio between the applied shear
stress and the rate of shear.
η=τ/γ
Asphalt Binder History and Background 22
23. Types of Viscosity Tubes
Zietfuchs Cross-Arm
Asphalt Institute Tube
Tube
Asphalt Binder History and Background 23
24. Testing
Absolute viscosity
– U-shaped tube with
timing marks & filled with
asphalt binder
– Placed in 60C bath
– Vacuum used to pull
asphalt through tube
– Time to pass marks
– Visc. in Pa s (Poise)
Asphalt Binder History and Background 24
25. Testing
Kinematic viscosity
– Cross arm tube with timing
marks & filled with asphalt
– Placed in 135C bath
– Once started gravity moves
asphalt through tube
– Time to pass marks
– Visc. in mm2 / s (centistoke)
Asphalt Binder History and Background 25
26. Viscosity Grade Specifications
ASTM D3381
Three specifications
– Table 1
» Original properties
– Table 2
» Original properties
– Table 3
» Rolling thin film oven aging
Asphalt Binder History and Background 26
27. Table 1 & 2 Tests
Viscosities at 60 and 135oC
Penetrations at 25oC
Flash point
Solubility
TFO aged residue
– Viscosity at 60oC
– Ductility at 25oC
Asphalt Binder History and Background 27
28. Table 1 & 2 Grades
Table 1
– AC 2.5, AC 5, AC 10, AC 20, AC 40
Table 2
– AC 2.5, AC 5, AC 10, AC 20, AC 30, AC 40
Asphalt Binder History and Background 28
29. Table 1 Example
AC 2.5 AC 40
Visc, 60C 250 + 50 4,000 + 800
Visc, 135C 80+ 300+
Penetration 200+ 20+
Visc, 60C <1,250 <20,000
Ductility 100+ 10+
Asphalt Binder History and Background 29
30. Table 2 Example
AC 2.5 AC 40
Visc, 60C 250 + 50 4,000 + 800
Visc, 135C 125+ 400+
Penetration 220+ 40+
Visc, 60C <1,250 <20,000
Ductility 100+ 25+
Asphalt Binder History and Background 30
31. Ave. Mixing
Hot
Service &
Summer
Temp. Compaction
Viscosity (Stiffness)
40 Pen
60 Pen
2400
Low
1600 Table 2
300
210
Table 1
25C (77F) 60C (140F) 135C (275F)
Temperature
Asphalt Binder History and Background 31
32. Mixing/Compaction Temps
Viscosity, Pa s
10
5
1
.5
.3 Compaction Range
.2 Mixing Range
.1
100 110 120 130 140 150 160 170 180 190 200
Temperature, C
Asphalt Binder History and Background 32
33. Advantages
(Original AC Visc. Grade)
Fundamental property
Wide range of temperatures
Based on max. pavement surface temp.
Wide range of instruments
Test method precision established
Temperature susceptibility is controlled
Limits aging
Information on mixing & compaction temps.
Asphalt Binder History and Background 33
34. Disadvantages
(Original AC Visc. Grade)
More expensive
Longer testing time
More technician skill needed
Not applicable for Non-Newtonian materials
Wide range of properties for same grade
Asphalt Binder History and Background 34
35. Table 3
AR Grades
– AR 1000, AR 2000, AR 4000,
AR 8000, AR 16000
Tests on RTFO aged residue
– Viscosities at 60 and 135oC
– Penetrations at 25oC
– % of Original Penetration
– Ductility
– Properties of unaged asphalt
binders
» Flash point and solubility
Asphalt Binder History and Background 35
37. Table 3 Specification
AR 1000 AR 16,000
Visc, 60C 1,000 + 250 16,000 + 4,000
Visc, 135C 140+ 550+
Pen. 65+ 20+
% Orig. Pen NS 52+
Asphalt Binder History and Background 37
38. Advantages
(AR Visc. Grade)
Represents asphalt binder properties
after mixing
Fundamental properties
Covers wide range of temperatures
Limits aging
Asphalt Binder History and Background 38
39. Disadvantages
(AR Visc. Grade)
Highly regional
Requires different testing equipment
Longer testing time
No consistency test on original Asphalt Binder
Not applicable for Non-Newtonian materials
Wide range of properties for same grade
Asphalt Binder History and Background 39
40. Penetration Grades
AC 40 AR 16000
40
Viscosity, 60C (140F)
100 50 AC 20
AR 8000
60
50 AC 10
70 AR 4000
85
100 AC 5
AR 2000
120
150 AC 2.5
10 200 AR 1000
300
5
Asphalt Binder History and Background 40
At the conclusion of this block the student will understand: * How to use asphalt binder specifications * The limitations of these specifications which led to the development of new asphalt binder specifications This material is covered in detail in Chapter 2 “Asphalt Binder Refining, Uses, and Properties” in the recommended text book.
The first paved roadway in the United States was Pennsylvania Avenue in front of the White House. This pavement was constructed with an asphalt binder product quarried from a naturally occurring “lake” of asphalt on the island of Trinidad off the coast of Venezuela. A second source of this type of asphalt binder product can be found in Bermudez, Venezuela. These products are still used today. In fact, a Trinidad lake asphalt was placed near Mobile, Alabama in July, 1998. Each lake asphalt has consistent but different amounts of bitumen, inorganic material. Because of these consistent differences, the amount of solvent-insoluble inorganic material is one common method used to identify and specify the lake asphalt source. This solubility test was used in all subsequent asphalt binder specifications throughout the 20 th century.
During the late 1800's and early 1900's the demand for paved roads increased so fast that the time-intensive processing and shipping of lake asphalt was limiting the miles of paved roads constructed each year. This led to the increasing use of petroleum refinery-based asphalt binders. It is interesting to note that these asphalt binders were originally considered inferior to lake asphalt because of their crude source-dependent material properties.
Replica of the engine house and derrick at Oil Creek PA. On August 28, 1859, George Bissell and Edwin L. Drake made the first successful use of a drilling rig on a well drilled especially to produce oil, at a site on Oil Creek near Titusville, Pennsylvania. The Drake well is often referred to as the "first" commercial oil well. However, before the Drake well, oil-producing wells in the United States were wells that were drilled for salt brine, and produced oil and gas only as accidental byproducts. Historians have noted that the importance of the Drake well was not in being the first well to produce oil, but in attracting the first great wave of investment in oil drilling, refining, and marketing: "The importance of the Drake well was in the fact that it caused prompt additional drilling, thus establishing a supply of petroleum in sufficient quantity to support business enterprises of magnitude.
A number of products are obtained from one barrel of crude. Asphalt binder is what is left after the more volatile products are removed and it is commonly referred to as the “bottom of the barrel”.
In order to purchase a product, the desirable characteristics and important material properties must be known. When these parameters are presented in written form, they are called specifications.
The first approach to characterizing the stiffness of an asphalt binder was to chew on it. An engineer would take a small sample of material, roll it into a ball, and place it between their teeth. The pressure required to deform the ball was considered an indication of the stiffness of the asphalt binder. However, this method was very subjective and could not be used to routinely specify the particular requirements of an asphalt binder for a given construction project. These drawbacks eventually led to the development of the penetration test.
The penetration test started out using a No. 2 sewing machine needle mounted on a shaft for a total mass of 100 g. This needle was allowed to sink into (penetrate) a container of asphalt binder at room temperature (25 o C) for 5 seconds. The consistency (stiffness) of a given asphalt binder was reported as the depth in tenths of a millimeter (dmm) that the needle penetrated the asphalt binder.
This test was used to standardize the penetration grading system approach for specifying asphalt binders. This specification uses the penetration of the original asphalt binder in the grade names. That is, a 120-150 penetration grade asphalt binder will have a penetration value for the original asphalt binder of between 120 and 150 tenths of a millimeter.
Other tests have been added to address safety issues (the flash point test), the ability of the asphalt binder to deform without breaking (ductility test), and the influence of heat hardening on asphalt binder properties (thin film oven test).
If an asphalt binder is heated to a high enough temperature, it gives off sufficient vapors to flash (ignite) in the presence of a spark or open flame. The Cleveland Open Cup test determines the temperature at which this flash occurs. In this test, a small sample of asphalt binder is poured into the brass cup which is placed over an electric heater. A thermometer is submerged to a prescribed depth into the asphalt and used to monitor the temperature rise. When the temperature gets close to the suspected flash point, the gas line is turned on and a small flame lit at the end of the wand. The flash point is the temperature at which a small blue flicker around the inside of the cup is seen as the wand is passed horizontally over the surface of the cup.
This test evaluates the ability of an asphalt binder sample to stretch at a rate of 5 cm/min at 25 o C. The distance the samples can be pulled is measured directly from the centimeter scale mounted to the top of the tank. The significance of the ductility test to indicate performance-related properties has been debated for a number of years due to its empirical nature and poor reproducibility of test results. In general, asphalts binder with lower ductility have a greater tendency to produce pavements which have excessive cracking
A sample of asphalt binder is dissolved in a solvent then filtered through a Gooch crucible mounted in the top of a vacuum flask. The amount of insoluble material retained on the filter represents the impurities in the asphalt binder.
Thin film oven aging is a laboratory procedure for simulating the change in asphalt binder properties which occur during tank storage, mixing and construction processes. This test can also be used to measure the loss of volatiles in the asphalt binder by determining the percent difference in the mass before and after aging. A 50 g sample of asphalt binder is poured into each of three flat-bottomed pans. This results in a layer of asphalt binder of about 3.2 mm deep. Three pans are placed on a rotating shelf in a 163 o C oven for 5 hours. The aged samples are then combined into one container, mixed, and used to determine the aged asphalt binder properties.
There are five penetration grades of asphalt binder with discrete ranges. That is, there is no overlap in penetration values between grades. It is possible to have an asphalt binder which will not meet any penetration grading requirement. This table presents two of these grades. Note the flash point decreases with increasing penetration. This is because softer asphalt binders usually have a higher percentage of lighter ends which will “flash” at lower temperatures. The specification allows for this difference. Since these fractions of the asphalt binder are also easily removed by heating, this means that there will be a higher percentage mass loss on aging. This greater loss of the softer asphalt components is reflected in the differences in requirements on the percent of the original penetration retained after aging. That is, the more light ends lost during aging, the greater the stiffening affect due to aging. This loss of the softer asphalt binder components is also reflected the ductility requirements.
Temperature susceptibility (i.e., the rate of change in material properties with a change in temperature) can be estimated by determining the penetration at two (or more) temperatures. The most commonly used temperatures are 4 and 25 o C with a 100 g load for 5 seconds. This figure highlights one of the major problems with the penetration grading system. For example, three sources of asphalt binder can have the same penetration at 25 o C but decidedly different properties above and below this temperature. This helps explain the differences in observed pavement performances even though the same penetration grade of asphalt binder is specified.
Several advantages are responsible for the penetration specifications being widely used throughout the 20 th century. For instance, as late as 1995 the Minnesota Department of Transportation was still using this specification to purchase asphalt binder. These advantages include an estimate of material properties at the average in-service temperature (i.e, the average between summer highs and winter lows), low cost of the equipment, simplicity, and short testing times needed to obtain results.
However, there are several disadvantages associated with penetration specifications. These include allowing a wide range of material properties at high and low temperatures for a given penetration grade, variable shear rates (i.e., the needle will penetrate the asphalt faster for softer as compared to harder asphalts), lack of fundamental measurements needed for mechanistic pavement performance prediction models (i.e., no stress or strain measurements), their inability to evaluate shear rate dependent materials (e.g., polymer modified asphalt binders), and lack of information for selecting appropriate mixing and compaction temperatures (necessary information for preparing mixtures in the laboratory and plant).
These disadvantages led to the development of the viscosity grading system in the 1970's which is detailed in ASTM D3381. This one ASTM standard actually contains three separate specifications designated as: Table 1, Table 2, and Table 3. The first two specifications are based on the original properties of the asphalt while the last table is based on the properties of the asphalt binder after rolling thin film oven aging. Each of these tables and differences between them will be discussed in the following slides. In the early 1960s an improved asphalt grading system was developed that incorporated a rational scientific viscosity test. This scientific test replaced the empirical penetration test as the key asphalt binder characterization. Viscosity grading quantifies the following asphalt binder characteristics: Viscosity grading can be done on original (as-supplied) asphalt binder samples (called AC grading) or aged residue samples (called AR grading). The AR viscosity test is based on the viscosity of aged residue from the rolling thin film oven test. With AC grading, the asphalt binder is characterized by the properties it possesses before it undergoes the HMA manufacturing process. The AR grading system is an attempt to simulate asphalt binder properties after it undergoes a typical HMA manufacturing process and thus, it should be more representative of how asphalt binder behaves in HMA pavements. Table 1 lists key advantages and disadvantages of the viscosity grading system. Advantages Unlike penetration depth, viscosity is a fundamental engineering parameter. Test temperatures correlate well with: • 25° C (77° F) – average pavement temp. • 60° C (140° F) – high pavement temp. • 135° C (275° F) – HMA mixing temp. Temperature susceptibility (the change in asphalt binder rheology with temperature) can be somewhat determined because viscosity is measured at three different temperatures (penetration only is measured at 25° C (77° F)). Testing equipment and standards are widely available Disadvantages The principal grading (done at 25° C (77° F)) may not accurately reflect low-temperature asphalt binder rheology. When using the AC grading system, thin film oven test residue viscosities can vary greatly with the same AC grade. Therefore, although asphalt binders are of the same AC grade they may behave differently after construction. The testing is more expensive and takes longer than the penetration test. .
Viscosity is shear stress divided by the shear strain rate. These units of measurement provide at least a limited estimate of fundamental material properties. The easiest way to picture shear is to visualize a deck of cards which have a vertical line marked on the side. As pressure is applied to the top of the deck, the cards slide over one another and the marked dots on the individual cards start to separate. The shear rate is the rate at which these dots separate.
Two viscosity measurements are used in this specification: Absolute viscosity (60 o C) and kinematic viscosity (135 o C). Both use the principle of the rate of flow through a known area to measure viscosity. Because asphalt binder is still very thick (stiff) at 60 o C, a vacuum is needed to move the asphalt through the tube in a reasonable time. At 135 o C, gravity and a falling head pressure is sufficient to get the asphalt binder to flow.
At the 60 o C test temperature, the tube is charged at 135 o C and then placed in the test temperature bath. The tube temperature is allowed to equalize with the bath temperature, a vacuum line is attached to the top of the small diameter tube, and the flow is started. The time it takes the asphalt to flow past the timing marks times the tube calibration constant gives the viscosity of the asphalt binder in Poise.
The tube is charged in the 135 o C bath and left for about 20 minutes. A vacuum line is touched briefly to the top of the small diameter tube until the asphalt binder moves over the upper hump in the tube. The time it takes the asphalt binder to flow past the timing marks times the tube calibration constant gives the viscosity of the asphalt in centistoke. Centistokes are converted to centipoise by mulitplying centistokes by the specific gravity of the asphalt binder.
All three of the viscosity graded asphalt binder specifications are listed in ASTM D3381. The first two specifications are based on the viscosity of the original asphalt binder at 60 o C. The third specification is based on the viscosity of the rolling thin film oven aged residue at 60 o C.
Requirements on both the absolute and kinematic viscosities are set in these specifications. The grading system is based on the absolute viscosity (60 o C). A minimum viscosity at 135 o C is included to help define the maximum rate of change of material properties with temperature. A minimum penetration value is also included in these specifications as a means limiting temperature susceptibility. The penetration values decreases with increasing viscosity. In other words, the stiffer the asphalt binder, the less distance the needle will penetrate into the asphalt binder. As with the penetration specifications, requirements for safety and limits on aging of the asphalt binder during construction are included. The flash point temperature requirements increase with increasing viscosity (less volatiles with increasing viscosity). Maximum limits on viscosity after thin film oven aging limit the amount of acceptable aging during mixing and construction.
Table 2 viscosity specifications are very similar to Table 1 specifications with two exceptions: Table 2 specifications allow for an AC 30 grade, and Table 2 asphalt binders are required to be less temperature susceptible.
This table compares two of the viscosity graded Table 1 specifications. The viscosity grading system provides immediate information as to the mean anticipated viscosity at 60 o C. For example, an AC 25 will have a mean viscosity of 250 Poise (2.5 times 100). Because of the limited allowable range (coefficient of variance of 20 percent), there is no overlap between the AC grades.
All of the same tests are used to specific Table 1 and Table 2 specifications. The differences between the two specifications are highlighted in this example. While the original and maximum aged viscosities at 60 o C remain the same for both tables, the minimum requirements for the 135 o C viscosity and penetrations are increased. There is also an increase in the required ductility after aging for the harder (higher viscosity) asphalt binders.
This figure demonstrates the differences between a Table 1 and a Table 2 AC 20. Both asphalt binders can have similar viscosities at 60 o C. The minimum 135 o C for the Table 1 AC 20 is 210 centistokes. This minimum limits the steepness of the viscosity temperature line (i.e., puts a maximum on the temperature susceptibility. The higher minimum requirement (300 centistokes) for the Table 2 AC 20 further limits this slope. The minimum penetration value places a limit on maximum stiffness of the asphalt binder at 25 o C. Remember that higher penetration numbers represent lower asphalt binder stiffness. The higher minimum requirement for the Table 2 AC 20 also results in a shallower maximum slope. Neither Table 1 or Table 2 specifications place any lower limit on the rate of change in properties with temperature. This means that the pavement performance of a given AC 20 can still vary widely.
Information from this testing can be used to estimate appropriate mixing and compaction temperatures. This is accomplished by graphing viscosity in Poise (on a log scale of the y-axis) versus temperature (arithmetic scale on the x-axis). The mixing temperature is selected so that an equal viscosity is achieved. Based on historical experience, a viscosity of 1.7 + 0.2 Poise is used. The temperature at which the viscosity is 2.8 + 0.3 is used to select the compaction temperature.
Advantages to using viscosity specifications include measurements with engineering units, limits on maximum temperature susceptibility and changes in properties due to aging, and information can be obtained on appropriate mixing and compaction temperatures.
Disadvantages include the higher cost of the more sophisticated equipment and glassware required for viscosity tests, longer testing times, increased training needed for technicians, the lack of lower limits for temperature susceptibility, and the inability of these viscosity measurements for assessing non-Newtonian (shear rate dependent) properties.
The rolling thin film oven places 35 g of asphalt binder in glass jars which are then anchored in a rotating carriage. As the carriage rotates, the asphalt binder rolls around the inside of jar and air is blown over the surface each time the jar passes the air nozzle at the bottom of the oven. This continually exposes a new surface of asphalt binder to the effects of air and heat. This test is run at 163 o C for 80 minutes. At the end of this time, the asphalt binder is scraped out of the jars and combined into one container, stirred, and used to determine the effects of oxidation and heat aging on viscosity, penetration, and ductility.
The allowable range of RTFO aged viscosities is greater than those for the AC viscosity designations. The coefficient of variation is 25 percent. The only tests which are conducted on the original asphalt binder are flash point and penetration (so that the percent of original penetration can be calculated).
The main advantage to this specification is that it is based on the properties of the asphalt binder behind the paver. That is, it is based on the in-place asphalt binder properties at the time the roadway is opened to traffic. Other advantages to using the AR specification are similar to those for the first two viscosity specifications.
Disadvantages include a problem with a lack of wide-spread experience in determining desirable properties, longer times before results can be reported because the material has to be aged prior to testing, and other disadvantages as seen in the previous viscosity grading specifications.
This figure provides a general comparison of the various traditional specifications. While there is no direct relationship between the specifications, there is a general relationship between stiffness and viscosity. Higher penetration numbers correspond with lower viscosities.