Bituminous Materials and properties.pptx

This PPT describes about Bitumen and its properties

1. Bituminous Materials Ms.Kanemozhe R K M.Tech Department of Civil Engineering National Institute of Technology, Tiruchirappalli – 620015.

2. Paving Binders Bitumen Tar Cutback Emulsion Modified Binders

3. Bitumen and Tar - Origin Naturally occurring deposits of bitumen are formed from the remains of ancient, microscopic algae and other once-living things. When these organisms died, their remains were deposited in the mud on the bottom of the ocean or lake where they lived. Under the heat and pressure of burial deep in the earth, the remains were transformed into materials such as bitumen, kerogen , or petroleum. Deposits at the La Brea Tar Pits are an example. There are structural similarities between bitumens and the organic matter in carbonaceous meteorites. However, detailed studies have shown these materials to be distinct.

4. Bitumen and Tar - Origin Asphalt or bitumen can sometimes be confused with "tar", which is a similar black, thermoplastic material produced by the destructive distillation of coal. During the early and mid 20th century when town gas was produced, tar was a readily available product and extensively used as the binder for road aggregates. The addition of tar to macadam roads led to the word tarmac, which is now used in common parlance to refer to road-making materials. However , since the 1970s, when natural gas succeeded town gas, asphalt (bitumen) has completely overtaken the use of tar in these applications. BITUMEN is a petroleum product obtained by the distillation of petroleum crude. TAR is a thermoplastic material obtained from the destructive distillation.

5. Sl. No. Bitumen Tar 1 Bitumen is found in black to brown in colour Tar is usually found in brown colour 2 Bitumen is obtained from fractional distillation of crude oil Tar is obtained by destructive distillation of coal or wood 3 Bitumen is soluble in carbon disulphide and carbon tetra chloride Tar is soluble in toluene 4 Molecular weight range for road bitumen is 400 to 5000 Molecular weight range for road tar is 150 to 3000 5 Bitumen consists of large amount of aromatic hydrocarbon Tar consist of large amount of oily matter with lower molecular weight 6 Bitumen show resistance to coating road aggregate and also does not retain in presence of water Tar coats more easily and retain it better in presence of water 7 Free carbon content is less Free carbon content is more 8 It shows more resistance to weathering action It shows less resistance to weathering action 9 Less temperature susceptibility More temperature susceptibility

6. Bitumen Bitumen is a complex material, its property ranges from viscous liquid to brittle solid. While bitumen shows linear viscoelastic behaviour at small strains, the nonlinear behaviour becomes more prominent at large strains ( Monismith and Secor 1962, Pagen 1968, Cheung and Cebon 1997). The deformation of bitumen is loading rate and temperature dependent (Van der Poel , 1955, Deshpande and Cebon 1997).

7. Early uses of Bitumen in History Ancient uses in Road Construction

8. Known for its adhesive and cohesive assets, bitumen is mostly utilised in the construction industry. Bitumen is applied on road paving because it is viscous when hot, but solid once it cools down. Therefore Bitumen operates as the binder/glue for pieces of the aggregate. Bitumen is applied in construction and maintenance of : Highways Reservoir and pool linings Airport runways Soundproofing Footways / Pedestrian Ways Pipe coatings Car parks Cable Coatings Racetracks Paints Tennis courts Building Water Proofing Roofing Tile underlying waterproofing Damp proofing Newspaper Ink Production Dams And many other applications Bitumen - Applications

9. Global Bitumen The global bitumen market size was USD 66.10 billion (around Rs.4.2 trillion) in 2015 and is expected to witness significant growth over the next eight years owing to increasing use in various applications.

10. Global Bitumen The  Indian bitumen market   that is currently around 5 million tonnes is expected to grow in the future due to the Government’s proposed construction projects to upgrade the road network . In India, Bitumen is mostly used as a binder in road construction and in roofing and waterproofing applications. Nearly  90% of this demand is provided from domestic production of bitumen, whilst the remaining 10% is imported, mainly from the UAE and Iran . The bitumen currently used in India are either penetration grades or the currently preferred viscosity grades .

11. Global Bitumen In the emerging global bitumen market, demand is expected to reach 122 million tonnes by 2018. Increasing road construction activities in the fast-growing markets of India and China will be the main growth drivers of the bitumen market in Asia . During 2014–2015, total bitumen sales in India were 4.8 million tonnes.  VG 10 bitumen comprises 35% of demand in India , VG 30  comprises 60% of demand and VG 40 comprises 5% of demand.

12. Bitumen - Properties Petroleum Bitumen, normally called “Bitumen” or “Asphalt” is produced by refining crude oil. Natural or Refined, Blend of heavy Hydrocarbons Chemical constituents: Maltenes , Asphaltenes Bitumen is often defined as suspension of Asphaltene into a Maltene matrix. Properties and qualities of bitumen depend on the crude oil used for its manufacture. Important Properties

13. Bitumen - Manufacturing It is produced to grade specification either by directly refining or by blending. Polymers and additives are sometimes used to modify the thermoplastic characteristics of bitumen to enhance final product performance. The crude oil is pumped from storage tanks, where it is kept at about 60°C, through a heat exchanger system where its temperature is increased to typically 200°C by exchanging heat gained from the cooling of newly produced products in the refining process. The crude is then further heated in a furnace to typically 300° C where it is partly vaporized into an Atmospheric Distillation Column. Here the physical separation of the components occurs.

14. Bitumen - Manufacturing The lighter components rise to the top and the heaviest components (the atmospheric residue) fall to the bottom of the column and pass through a second heat exchanger prior to treatment in a vacuum distillation column. Finally , Bitumen is obtained by vacuum distillation or vacuum flashing of atmospheric residue from the vacuum distillation column. This is “ straight run bitumen ”. An alternative method of bitumen production is by precipitation from residual fractions by propane or butane-solvent deasphalting . The bitumen thus obtained has properties which derive from the type of crude oil processed and from the mode of operation in the vacuum unit or in the solvent deasphalting unit. The grade of the bitumen depends on the amount of volatile material that remains in the product: the smaller the amount of volatiles, the harder the residual bitumen.

15. Standard Bitumen Production Scheme

16. Typical Bitumen Production Scheme

17. Crude oil analysis and Selection The crude oil or blends of crude oils can come from several sources, those that would be naturally occurring and those created or extracted from oil sands or shale. Only a limited number of crude oils or blends are considered are suitable for producing bitumen of the required quality in commercial quantities. In general, heavy crude oils (G > 0.9) are used. These crude oils tend to contain higher sulphur contents. Common practice – Blending crude oils Oil sand, shale oil and Oil shale

18. Crude oil Variations

19. Influence of Crude source

20. Distillation Most common refining process is straight reduction to grade from petroleum crude oil or a crude blend, using atmospheric and vacuum distillation. Atmospheric distillation is used for physically separate light, lower boiling point, petrochemical and fuel fractions from the non boiling component known as Atmospheric Residuum . To remove the last traces of light of the lighter fractions and avoid thermal transformation of the molecules, the atmospheric residuum is introduced into a Vaccum distillation unit. Depending on the specification grade requirements, the vacuum residuum can be used either directly, further processed, or used as a component of blended bitumens .

21. Schematic diagram of the Distillation Process

22. Air Rectification A mild degree of air-blowing is commonly used to make minor adjustments to the physical properties, such as decreasing the penetration and/or increasing the stiffness of the bitumen. Air rectified bitumens are predominantly used in paving applications and the application temperature is equal to paving application temperatures using straight run bitumens . Air rectified bitumen materials are also used for the production of polymer modified binder grades and as the base bitumen for the production for the production of bitumen emulsion.

23. Solvent Deasphalting The properties of vacuum residuum can be modified by use of subsequent refining process steps. ROSE – Residual Oil Solvent Extraction Propane, Butane, Isobutene, pentane or super critical solvent extraction To separate asphaltene type fractions from residuums for producing lubricating oil base stocks. The hard bitumen remaining can be blended to producing specification grade bitumen.

24. Schematic diagram of Propane Deasphalting Process

25. Vacuum Distillation of Thermal Cracked residuum In a visbreaking unit, a residue stream is heated to temperatures between 440-500°C. Long paraffinic side chains attached to aromatic rings are the primary cause of the high pour point and viscosity seen with residues. Visbreaking is carried out under conditions optimised to break off these long side chains and subsequently transform them to form shorter molecules with lower viscosity and pour point . When used for bitumen production the thermally cracked residuum is subjected to vacuum distillation to remove the distillate fractions which are then further treated and used in the fuel production. The product obtained after vacuum distillation is a hard material which can be used as a blending component for bitumen production.

26. Schematic diagram of the Thermal cracking Process

27. Oxidation Oxidised or Blown bitumen 85-140 cum/min of air through bitumen feedstock at elevated temperatures  Change in Physical properties Varying degrees of chemical reactions  Increase in apparent molecular weight and polarity of bitumen  Stiffening of Bitumen Catalysts (not true): Ferric chloride, Hydrochloric acid, Phosphorous pentoxide , Phosphoric acid, Flux (Europe) Oxidation unit: Reactor vessel, Air blower, off-gas treatment facility and temperature control equipment

28. Oxidation The oxidation reaction is Exothermic. Reactor may be fitted with a water jacket and/or water spray facility at the head of the reactor, or internal addition of water, to control the bitumen temperature . Injection of steam/water into the reactor head space may also be used to reduce the oxygen content of the off-gases to manage the risk of fire or explosion. The rate of oxidation depends on feedstock properties and operating parameters.

29. Schematic diagram of the Bitumen Oxidation Process

30. Other Processes To produce small amounts of bitumen Further treatments or extraction processes applied to residual materials, to remove or convert constituents that are unsuitable for bitumen performance. Hydrodesulphurisation, Hydrogenation

31. Bitumen Blending To meet specifications Higher and Lower viscosity products or bitumen are blended together. Blending at refinery, terminals or 3 rd party facility where blend components and finished products can be easily transported by truck, rail or barge to their final locations.

32. Bitumen – Chemical Characteristics Complex chemical mixture of molecules that are predominantly hydrocarbons. Predominantly soluble in Carbon disulphide Mostly in colloidal state Composition: Carbon – 82 - 88% Hydrogen – 8 - 11% Sulphur – 0 - 6% Oxygen – 0 - 1.5% Nitrogen – 0 - 1% Traces of metals – Vanadium, Nickel, Iron, Magnesium, Calcium Complete chemical analysis of bitumen is very difficult Asphaltenes (5-25%) are responsible for viscosity

33. Bitumen Processing ASTM D4124-09 Standard Test Method for Separation of Asphalt into Four Fractions ASTM D2007 – 11 Standard Test Method for Characteristic Groups in Rubber Extender and Processing Oils and Other Petroleum-Derived Oils by the Clay-Gel Absorption Chromatographic Method

34. Study of Bitumen Bitumen is a visco -elastic material. Hence its properties are dependent on temperature and rate of loading . Purity of material Safety in handling Cohesion Adhesion to aggregate Workability / Fluidity / Consistency for different operations Durability during service life of pavement Behaviour at high, low and average service temperature Behaviour at high temperature associated with construction activities

35. Purity of Bitumen Pure bitumen completely dissolves in Carbon Disulphide. Percentage insoluble material indicates the impurity of bitumen. Bitumen should be free of water as it causes foaming at high temperature. Test: Water content test ASTM D2042 – 15: Standard Test Method for Solubility of Asphalt Materials in Trichloroethylene ASTM D1461 – 17: Standard Test Method for Moisture or Volatile Distillates in Asphalt Mixtures

36. Solubility Test – ASTM D2042 Degree of solubility in Trichloroethylene of Asphalt materials having no or less mineral matter. The portion that is soluble in trichloroethylene represents the active cementing constituents. This method is not applicable to tars and their distillation residues or highly cracked petroleum products . The sample is dissolved in trichloroethylene and filtered through a glass fiber pad. The insoluble material is washed, dried, and weighed.

37. Bitumen or Gooch crucible – Glazed inside and outside; top dia-44 mm, tapered bottom dia-36 mm, depth-20 to 30 mm. Filter tube - 40 to 42 mm inside dia Filter flask – Heavy wall, 250, 500 or 1000 mL capacity Glass micro fiber filterpad – 30 – 32 mm dia , fine porosity, 1.5 micrometre particle retention Rubber Tubing or Adapter - for holding the crucible on the filter tube . Erlenmeyer Flask, 125 mL. Oven , capable of maintaining a temperature of 110±5°C. Reagent - Trichloroethylene Apparatus Required

38. Procedure Crucible preparation: Place the crucible plus one thickness of the filter pad in an oven at 110±5°C for 15 min. Allow to cool in a desiccator for 30±5 min, and then determine the mass to the nearest 0.1 mg . Designate this mass as A. Store in the desiccator until ready for use . Sample preparation: If the sample is not fluid, heat to any convenient temperature, but in any case not more than 100°C above the softening point . Normally the temperature at which this test is run is not critical, and it may be performed at the laboratory air temperature.

39. Procedure Transfer approximately 2 g of the sample into a tared 125-mL Erlenmeyer flask or other suitable container. Smaller sample sizes may be necessary if more than 0.5 % insoluble material is expected. Allow the sample to cool to ambient temperature and then determine the mass to the nearest 1 mg. Designate this mass as B. Add 100 mL of the trichloroethylene to the container in small portions with continuous agitation until all lumps disappear and no undissolved sample adheres to the container . Stopper the flask or otherwise cover the container and set aside for at least 15 min Place the previously prepared and weighed crucible in the filtering tube. Wet the filter pad with a small portion of trichloroethylene and decant the solution through the filter pad of the crucible with or without light suction as may be necessary.

40. Procedure When the insoluble matter is appreciable, retain as much of it as possible in the container until the solution has drained through the mat. Wash the container with a small amount of solvent and, using a stream of solvent from a wash bottle, transfer all insoluble matter to the crucible. Use a “policeman” if necessary to remove any insoluble matter adhering to the container. Rinse the policeman and container thoroughly. Wash the insoluble matter in the crucible with solvent until the filtrate is substantially colourless , then apply strong suction to remove the remaining solvent. Remove the crucible from the tube, wash the bottom free of any dissolved matter, and place the crucible on top of an oven or on a steam bath until all odour of the trichloroethylene is removed. Place the crucible in an oven at 110±5°C for at least 20 min. Cool the crucible in a desiccator for 30±5 min and determine its mass to the nearest 0.1 mg. Repeat the drying and weighing until constant mass is obtained. Designate this mass as C.

41. Results:

42. Moisture or Volatile Distillates – ASTM D1461-17 Determination of moisture or volatile petroleum fractions of the asphalt in asphalt mixtures. Apparatus: Metal Still - A vertical cylindrical still having a faced flange at the top to which the head is tightly attached by means of a clamp. The head shall be of metal, preferably of copper or brass, and shall have a tube opening of 25.4 mm of inside diameter to facilitate attachment of the specified trap/condenser assembly . Trap - W ell-annealed glass. For determination of water in asphalt mixtures, a glass trap of 10- or 25-mL capacity shall be used. Condenser -Water-cooled reflux glass-tube type, having a condenser jacket not less than 400 mm long with an inner tube 9.5 to 12.7 mm in outside diameter. End of the condenser inserted in the trap shall be ground off at an angle of 30° from the vertical axis.

43. Solvent – Aromatic solvent (High solvency and Dispersing power) – Xylene or a blend of 20% toluene and 80% xylene. For asphalt and similar petroleum products, a petroleum distillate, 5 % boiling between 90 and 100°C and 90% distilling below 210°C may be used. Heating Device— Any satisfactory source of heat that will be capable of maintaining a rate of distillation of 85 to 95 drops⁄min . Sampling: The sample shall be representative of the material and shall be of such size as practical to fill the container in which it is transported to the laboratory. For duplicate tests, a 1.9-L friction-top tin pail full of the material would be satisfactory. Test Specimen and Sampling: Thoroughly mix the sample and weigh out an amount estimated to show a percentage of moisture or diluent within the capacity of the trap calibration. Keep the remainder of the sample in its tightly covered container. The weighed sample should be preferably not less than 500 g for normal mixtures. Thoroughly break up this sample to avoid larger lumps, and place it in the still .

44. Procedure for Moisture determination: After the sample has been placed in the still, add 200mL of the solvent and quickly stir it into the sample. Assemble the components of the apparatus, choosing the trap in accordance with the expected water content of the sample and making all connections vapour and liquid tight . Insert a gasket of heavy paper, moistened with water between the still body and cover . The condenser tube and trap must be chemically clean to ensure free drainage of water into the bottom of the trap. Insert a loose cotton plug in the tip of the condenser to prevent condensation of atmospheric moisture inside it. Circulate cold water through the jacket of the condenser. Apply heat at such a rate that refluxing will start within 5 to 10 min after the heat has been applied and the condenser solvent will drip into the trap at a rate of 85 to 95 drops/min . Continue the distillation until three successive readings of the trap at 15-min intervals show no increase in the amount of water being condensed, except that in no case shall distillation continue for more than 1.5 h. Allow the contents of the trap to reach room temperature and read the volume of water in the trap to the nearest scale division. Record the volume of water and calculate in weight percent .

45. Procedure for Volatile Distillates determination : After the sample has been placed in the still, add 350mL of water and approximately 3 g of sodium carbonate (Na2CO3) and quickly stir into the sample. Firmly attach the still cover and assemble the trap and condenser, except that the gasket is moistened with solvent and the trap used shall be the dilution trap. Apply heat at such a rate that the water and solvent will begin to reflux in 5 to 10 min after the heat has been applied and will drip from the condenser at the rate of 85 to 95 drops⁄min . In case the sample contains a large amount of very volatile solvent, it may be necessary to add a second water-cooled condenser above the first one or to reduce the rate of distillation somewhat to prevent escape of the solvent. Continue distillation until three successive readings of the upper and lower levels of the diluent at 15-min intervals show no increase in the quantity being collected. Then remove the source of heat and allow the trap and contents to reach room temperature. Allow the trap to stand a minimum of 30 min to permit the solvent to separate. Record the volume of diluent in the trap to the nearest scale division and calculate in weight percent .

46. Calculation

47. Safety in handling Bitumen is heated to high temperatures and it should be safe to handle at such temperatures. Test: Flash and Fire Point Flash point is used in shipping and safety regulations to define flammable and combustible materials. It can indicate the possible presence of highly volatile and flammable materials in a relatively non-volatile or non-flammable material . The fire point is one measure of the tendency of the test specimen to support combustion. ASTM D92-16b: Standard Test Method for Flash and Fire Points by Cleveland Open Cup Tester ASTM D93-16a: Standard Test Methods for Flash Point by Pensky -Martens Closed Cup Tester

48. Consistency of Bitumen Degree of fluidity at a particular temperature Test: Penetration test, Softening point, Ductility, Fraass Breaking point, Viscosity ASTM D5/D5M-13: Standard Test Method for Penetration of Bituminous Materials ASTM D113-17: Standard Test Method for Ductility of Asphalt Materials The Fraass Breaking Point is the temperature at which bitumen first becomes brittle, as indicated by the appearance of cracks when a thin film of the bitumen on a metal plaque is cooled and flexed in accordance with specified conditions. Viscosity – Fundamental Rheological property of bitumen

49. Viscosity It is the fundamental Rheological property of bitumen Rheology is the study of flow and deformation of materials. Sliding plate viscometer Rotational viscometer Efflux viscometers Capillary viscometer ASTM D2170/D2170M-10: Standard test method for Kinematic Viscosity of Asphalts ASTM D2171: Standard test method for Viscosity of Asphalts by Vacuum Capillary Viscometer ASTM D4402/D4402M-15: Standard test method for Viscosity determination of Asphalt at elevated temperatures using a Rotational Viscometer ASTM D7496-17: Standard test method of Emulsified Asphalt by Saybolt Furol Viscometer

50. Aging of Bitumen Inevitable phenomena when bitumen is subjected to environmental conditions in the presence of heat, light and oxidation Causes: Loss of volatile matter and oxidation Short term and Long term aging Short term – Storage, transportation, mixing and placing Long term – Oxidation during service life Properties: Harder and stiffer bitumen Penetration and Ductility reduce. Viscosity and Softening point increase.

51. Hardening Mechanism Reversible Change in reorientation of microstructure Reversible with temperature, mechanical energy Irreversible Permanent changes to microstructure Chemical changes and loss of material

52. Reversible Hardening Steric hardening Change in Structure during application of tensile load Extremely slow process occurring at room temperature Takes days to weeks to reach equilibrium conditions Application of constant tensile load on cylindrical specimen and total deformation is measured at a constant time interval.

53. Reversible Hardening Strain Hardening Change in reorientation due to deformation Material attains original consistency after the load is removed

54. Reversible Hardening Physical Hardening: Thermo-reversible process Occurs at low temperature range of -15 to -35°C Takes one or two days Occurs in all glassy materials irrespective of their chemical nature, crystallizable or wax fractions and length of molecular chains Rate of hardening is more rapid at the beginning and decreases with increasing isothermal storage

55. Irreversible Hardening Short term aging Changes to the material from the refinery to the end of mixing and compaction process. Repeated heating and cooling process during transfers High temperatures over a short period of time

56. Irreversible Hardening Long term Aging Changes over a period of time when it is laid on the pavement. Heating and cooling during changes in pavement service temperature Moderate temperatures over a long period of time

57. Factors affecting Ageing Age hardening occurs as a result of compositional changes in the bitumen. The changes that occur as a result of age hardening are as yet, not well understood, primarily due to bitumen being a rather complex mixture of organic molecules that vary widely in composition. Traxler identified 15 effects which may influence the chemical, rheological and adhesion characteristics of bitumen. Petersen identified 3 composition related factors that govern the changes that could cause hardening as follows: Loss of oily components of bitumen by volatility or absorption by porous aggregate Changes in chemical constitution of bitumen molecules from reaction with atmospheric oxygen Molecular structuring that produces thixotrophic effects Ref: Performance and Durability of Bituminous materials – Edited by J.G.Cabrera and J.R.Dixon

58. Traxler’s 15 effects causing aging Oxidation (in dark) Photooxidation under direct sunlight Volatilization Photooxidation under reflected light Photochemical action of direct light Photochemical action of reflected light Polymerization Age hardening Exudation of oil Changes by nuclear energy Action of water Absorption of oil by solid Absorption of asphaltic components at solid surface Chemical reactions or catalytic effects Microbiological deterioration

59. Measurement of Aging Thin Film Oven test, Rolling Thin Film Oven Test for short term aging. ASTM D1754-09: Standard Test Method for Effects of Heat and Air on Asphaltic Materials (Thin-Film Oven Test ) ASTM D2872-12: Standard Test Method for Effect of Heat and Air on a Moving Film of Asphalt (Rolling Thin-Film Oven Test ) Pressure Aging Vessel for Long term Aging . ASTM D6521-13: Standard Practice for Accelerated Aging of Asphalt Binder Using a Pressurized Aging Vessel (PAV)

60. Thin-Film Oven Test-D1754 D etermination of the effects of heat and air on a film of semisolid asphaltic materials The effects of this treatment are determined from measurements of selected asphalt properties before and after the test . Indicates approximate change in properties of asphalt during conventional hot-mixing at about 150°C [302°F] as indicated by viscosity, penetration, or ductility measurements. It yields a residue which approximates the asphalt condition as incorporated in the pavement. If the mixing temperature differs appreciably from the 150°C [302°F] level, more or less effect on properties will occur.

61. TFOT A film of asphaltic material is heated in an oven for 5 h at 163°C [325°F]. The effects of heat and air are determined from changes incurred in physical properties measured before and after the oven treatment. An optional procedure is provided for determining the change in sample mass. Precision values for the method have been developed for viscosity, viscosity change, penetration change, mass change, and ductility.

62. Apparatus: Oven - Rotating Shelf—The oven shall be provided with a single metal circular shelf having a minimum diameter of 250 mm [9.8 in.] and a maximum diameter of 450 mm [18 in.].The shelf construction shall be such that it provides a flat surface for support of the containers without blocking all air circulation through the shelf when the containers are in place. The shelf shall be suspended by a vertical shaft and centered with respect to the horizontal interior dimensions of the oven and shall be provided with a mechanical means of rotating it at the rate of 5.5 ±1.0 r/min . The preferred vertical position for the shelf is 150 mm [6 in.] above the bottom of the oven (exclusive of space occupied by the heating element). The shelf shall be constructed or marked in such a way that the sample containers can be placed in the same position during each test. There shall be a minimum of two and a maximum of six sample container positions. Each sample container position shall be symmetrical with respect to the shaft and to any holes in the shelf. The number of sample container positions shall be the maximum that will fit on the shelf without violating the above requirements and without excessive overhang. Thermometric Device—An ASTM Loss on Heat Thermometer having a range from 155 to 170°C and conforming to the requirements for Thermometer 13C or a Grade A platinum resistance thermometer, commonly known as a PRT or an RTD (or both), connected to a meter readable to 0.1°, and verified accurate at 163°C [325°F], shall be used for determining the test temperature. The 13C thermometer, if used, shall be supported f rom the shaft of the circular shelf in a vertical position at a point equidistant from the center and outer edge of the shelf. The bottom of the thermometer bulb shall be 40 mm [1.5 in.] above the top of the shelf . The thermometer shall be radially centered over a sample container position. If a PRTor RTD is used for determining the test temperature, it shall be independent of the oven temperature control system and the tip of the measuring sensor shall be positioned 40 mm [1.5 in.] above the top of the shelf and centered over the arc of the rotating pans. Thermometric devices shall be calibrated when initially installed, and their accuracy at 163°C [325°F] shall be verified at least annually thereafter.

63. Container—Cylindrical pans, 140±1 mm [ 5.5±0.04 in.] in inside diameter and 9.5±1.5 mm [3⁄ 8±1 ⁄16 in.] deep with a flat bottom. Fifty millilitres of the sample in this size container give a film thickness of approximately 3.2 mm [1⁄8 in.]. Pans shall be made of stainless steel and shall have a metal thickness of approximately 0.64 mm [0.025 in .]. Preparation of Oven: Ensure that the thermometric device tip is positioned 40 mm [1.5 in.] above the top of the shelf and centered over the arc of the rotating pans. Ensure the oven is level so that the shelf rotates in a horizontal plane. The maximum tilt during rotation shall not be more than 3° from the horizontal. Preheat oven for a minimum of two hours prior to testing, with the control setting adjusted to the setting that will be used during the test. The setting shall be selected such that when the oven is fully loaded, the oven will equilibrate at 163.0±1°C [ 325±2°F ].

64. Preparation of Samples Place sufficient material for the test in a suitable container and heat to a fluid condition. Extreme care should be taken so that there is no local overheating of the sample and that the highest temperature reached is not more than 163°C [325°F]. Stir the sample during the heating period, but avoid incorporating air bubbles in the sample. Transfer 50±0.5 g into each of two or more tared containers. At the same time, pour a portion of the sample into the containers specified for measurement of original asphalt properties. Complete the tests by appropriate ASTM Test Methods D5, D2170, orD2171. If the quantitative value of the mass change is desired, cool the samples for the oven test to room temperature and determine the mass of each sample separately to the nearest 0.001 g. If the mass change is not required, allow the samples to cool to approximately room temperature before placing in the oven

65. Procedure With the oven preheated and adjusted, quickly place the asphalt samples in the predetermined sample container positions on the circular shelf. Fill any vacant positions with empty sample containers, so that every sample container position is occupied. Close the oven door and start rotating the shelf. Maintain the specified temperature range for 5 h after the sample has been introduced and the oven has again reached that temperature. The 5-h period shall start when the temperature reaches 162°C [323°F] and in no case shall the total time that a sample is in the oven be more than 51⁄4 h. At the conclusion of the heating period, remove the samples from the oven. If the mass change is being determined, cool to room temperature, determine the mass to the nearest 0.001 g, and calculate the mass change on the basis of the asphalt in each container (Note 6). After determining the mass of the samples, place them on a refractory-board and then on the shelf of the oven maintained at 163°C [325°F]. Close the oven and rotate the shelf for 15 min. Remove each pan individually and transfer the contents by pouring and scraping into a seamless metal container of approximately 240-mL [8-oz] capacity. Remove substantially all of the material from the pans by scraping with a suitable tool such as a spatula or putty knife. While the residue is being removed from each pan, the oven door shall remain closed, with the heater power on, and the remaining samples rotating on the shelf. The final pan shall be removed from the oven within 5 min of the removal of the initial pan. Stir the combined residues thoroughly, in a semi fluid state, until homogenous. If needed, heat the combined residues in the covered metal container in an oven at a temperature not exceeding 163°C [325°F]. Complete the tests on residue by appropriate ASTM Test Methods D5, D2170, orD2171 within 72 h of performing this test.

66. Rolling Thin-Film Oven Test-D2872 The RTFO was developed as an improvement to the Thin-Film Oven Test (TFOT) for short term asphalt binder aging. The TFOT placed asphalt binder samples in shallow pans and then heated them in an oven for an extended period of time to accomplish simulated aging. The RTFO is an improvement over the TFOT because: Fresh asphalt binder is continuously exposed to heat and air flow due to the rolling action of the carousel. Asphalt binder modifiers, if used, usually remain dispersed in the asphalt binder due to the rolling action of the carousel. No surface skin, which inhibits aging, forms on the asphalt binder because of the rolling action of the carousel. The test is reasonably short at 85 minutes.

67. This test method indicates approximate change in properties of asphalt during conventional hot-mixing at about 302°F (150°C) as indicated by viscosity and other rheological measurements. It yields a residue which approximates the asphalt condition as incorporated in the pavement. If the mixing temperature differs appreciably from the 302°F (150°C) level, more or less effect on properties will occur. This test method also can be used to determine mass change, which is a measure of asphalt volatility . A moving film of asphaltic material is heated in an oven for 85 min at 325°F (163°C). The effects of heat and air are determined from changes in physical test values as measured before and after the oven treatment.

68. Apparatus: Oven Flow meter – It may be any suitable type capable of accurately measuring the airflow at a rate of 4000 mL/min. The flowmeter shall be located downstream of all regulating devices and upstream of the copper coil. The flowmeter shall be positioned so it is maintained at approximately room temperature. Thermometer Container - The container in which the sample is to be tested shall be of clear, transparent, heat-resistant glass. Cooling Rack - A wire or sheet metal rack, constructed of stainless steel or aluminum , which allows the sample containers to cool in a horizontal position, with each container in the same horizontal plane. The rack shall be constructed in a way that allows air to flow freely around each container with at least 1 in. (2.5 cm) clearance between containers and at least 1 in. (2.5 cm) clearance between the containers and any solid surface.

69. RTFO

70. Determination of Oven Preheat Time Adjust the oven control thermostat to the setting that will be used during the test. Select this setting so that when the oven is fully loaded and the air is on, the oven will equilibrate at 325±1°F ( 163±0.5°C ), as indicated by the test thermometer. Turn the oven on and simultaneously record the start time to the nearest whole minute. Determine and record the temperature of the oven at 15-minute intervals. Continue this process until the oven reaches thermal equilibrium. Thermal equilibrium is considered to be the time when the oven temperature does not vary by more than 1ºF (0.5ºC) between two consecutive readings. The oven preheat time is the time that it takes to reach thermal equilibrium plus an additional 30 minutes . In lieu of completing the steps described above, a minimum preheat time of 4 hours may be used .

71. Preparation of Oven Position the air outlet orifice so that it is 1⁄ 4in±1 ⁄ 8in . (6 mm±3 mm) from the opening of the glass container. The orifice shall also be so positioned that the jet blows horizontally into the central arc of the opening of the circling glass container. Position the thermometer so that the end of the bulb of the thermometer is within 1 in. (25.4 mm) of an imaginary line level with the center of the shaft holding the revolving carriage. Level the oven so that the horizontal axes of the glass containers when in position in the carriage are level to within ±1.0 °. Start the fan . The fan shall remain on whenever the oven heater is on and the oven door is closed. Preheat the oven for the preheat time or longer prior to testing with the control thermostat adjusted to the setting that will be used during the test. Select this setting so that when the oven is fully loaded and the air is on, the oven will equilibrate at 325±1°F ( 163±0.5°C ), as indicated by the test thermometer .

72. Procedure: Heat the sample in its container with a loosely fitted cover in an oven not to exceed 302°F (150°C) for the minimum time necessary to ensure that the sample is completely fluid. Manually stir the sample but avoid incorporating air bubbles. Pour 35±0.5 g of the sample into each of the required glass containers, providing sufficient material for characterizing tests which are to be run on the residue. Immediately after pouring the sample into a glass container, turn the container to a horizontal position. Rotate the container slowly for at least one full rotation, and attempt to pre-coat its cylindrical surface. It is not necessary to pre-coat the open end of the container, and care should be taken to prevent the sample from flowing out of the container during this step. Place the container horizontally in a clean cooling rack that is maintained in a draft-free, room-temperature location away from ovens and other sources of heat . Allow the glass sample containers to cool in the cooling rack for a minimum of 60 min, and a maximum of 180 min . With the oven at operating temperature and the airflow set at 4000±200 mL/min, arrange the containers holding the asphalt in the carriage so that the carriage is balanced. Fill any unused spaces in the carriage with empty containers. Close the door and rotate the carriage assembly at a rate of 15±0.2 r/min.

73. Maintain the samples in the oven with the air flowing and the carriage rotating for 85 min. The test temperature of 325±l°F ( 163±0.5°C ) shall be reached within the first 10 min; otherwise, discontinue the test. At the conclusion of the testing period, remove any samples for mass change determination and place them horizontally in the cooling rack. Then, remove each remaining glass sample container, one at a time, and transfer its contents to a collection container having a capacity at least 30 % greater than the total expected volume of residue . This transfer shall be accomplished by first pouring out any residue that will flow freely from the glass sample container and then scraping out as much of the remaining residue as practical. While the residue is being removed from each sample container, the oven door shall remain closed, with the heater power on, the air on, and the remaining samples rotating in the carriage. The final container shall be removed from the oven within 5 min of removal of the initial container. Test the residue within 72 h of performing the RTFO test. If the mass change is being determined, allow the designated residue sample containers to cool on the cooling rack for a minimum of 60 min and a maximum of 180 min. After cooling, determine the mass of these container. Separately place each container vertically on the balance, and record the mass. Note whether any sample appears to have flowed out of the bottle .

74. Pressurized Aging Vessel – D6521 Accelerated aging (oxidation) of asphalt binders by means of pressurized air and elevated temperature. This is intended to simulate the changes in rheology which occur in asphalt binders during in-service oxidative aging but may not accurately simulate the relative rates of aging. It is normally intended for use with residue from Test Method D2872 (RTFOT), which is designed to simulate plant aging. The aging of asphalt binders during service is affected by ambient temperature and by mixture-associated variables, such as the volumetric proportions of the mix, the permeability of the mix, properties of the aggregates, and possibly other factors. This conditioning process is intended to provide an evaluation of the relative resistance of different asphalt binders to oxidative aging at selected elevated aging temperatures and pressures, but cannot account for mixture variables or provide the relative resistance to aging at in-service conditions.

75. Asphalt binder is normally first conditioned using RTFOT. Residue from the RTFOT is then placed in standard stainless steel pans and aged at the specified conditioning temperature for 20 h in a vessel pressurized with air to 2.10 MPa . The conditioning temperature is selected according to the grade of asphalt binder. The residue is then vacuum degassed. Temperature Simulation 194°F (90°C) cold climate 212°F (100°C) moderate climate 230°F (110°C) hot climate

76. Apparatus: An equipment system consisting of a pressure vessel, ovens, pressure-controlling devices, temperature-controlling devices, pressure and temperature measuring devices, and a temperature and pressure recording system

77. Pressure Vessel - A stainless steel pressure vessel designed to operate at 2.1±0.1 MPa between 90 and 110°C with interior dimensions adequate to hold ten PAV pans and a pan holder.

78. Pressure and Temperature Controlling Devices: A pressure relief valve A pressure regulator or regulating system A slow-release bleed valve or pressure controller Temperature Controlling Device—A digital temperature control device for maintaining the temperature at the conditioning temperature 60.5°C. A heating device (forced-draft oven or fluid bath) capable of maintaining the temperature within the pressure vessel. A pressure vessel with an integral temperature control system that is capable of restoring the pre-conditioning temperature , within the vessel after loading the pans and the pan holder, prior to pressurizing the vessel within 2 hours of placing the loaded vessel in the heating device, and maintaining the temperature within the pressure vessel. Stainless Steel Pans - Cylindrical pans, each 140 1 mm ( 5.5 0.04 in.) in inside diameter and 9.5 1.5 mm ( 3/8 1/16 in.) deep, with a flat bottom.  

79. Procedure Place the pan holder inside the pressure vessel. Combine the hot residue from the RTFOT bottles into a single container, stir to blend, and then transfer to PAV pans for PAV conditioning, or allow the hot residue in the container to cool to room temperature and cover and store at room temperature for PAV conditioning at a later date. If conditioned asphalt binder is allowed to cool to room temperature, heat it until it is sufficiently fluid to pour and stir it before pouring it into the PAV pans. Place each PAV pan on a balance and add 50±0.5 g mass of asphalt binder to the pan. This will yield approximately a 3.2-mm thick film of asphalt binder. Place the filled pans in the pan holder . Place the panholder with filled pans inside the pressure vessel and close the pressure vessel. Unused slots in the pan holder need not be filled with empty pans. If an oven is used, place the loaded and closed pressure vessel in the oven. If the temperature inside the vessel has not reached the desired temperature for applying pressure within 2 h of loading the pan holder and pans, discontinue the procedure and discard the asphalt samples.

80. Maintain the temperature and air pressure inside the pressure vessel for 20 h±10 min . At the end of the 20-h conditioning period, begin the slow reduction of the internal pressure of the PAV, using the air pressure bleed valve. The bleed valve should be preset to an opening that requires 8 to 15 min to equalize the internal and external pressures on the PAV, thus avoiding excessive bubbling and foaming of the asphalt binder . Vacuum degas the aged samples . Remove the pan holder and pans from the PAV, and place the pans in an oven set to 168±5°C for 15±1 min . Preheat the vacuum oven to 170±5°C. Remove the pans from the oven and scrape the hot residue from all pans containing the same sample into a single container. After the last pan of a sample has been scraped, and if additional containers are to be prepared, transfer the container to the 168°C warming oven. After all of the containers have been prepared, transfer them to the vacuum oven within one min. Once the last container has been placed in the vacuum degassing oven, maintain the temperature .

81. Temperature susceptility of binders Bitumen is thermoplastic. Variation in consistency with temperature is known as Temperature susceptibility. Penetration index A – Temperature susceptibility 0.015-0.06 for paving bitumen

82. Penetration Index is correlated to A by PI value ranges from -3 (for highly susceptible bitumen) to +7 (for low susceptibility, highly blown bitumen)  

83. Gradation of Bitumen Penetration Grading Viscosity Grading Performance Grading

84. Cutbacks Low viscosity bitumen whose viscosity is reduced by Volatile solvents After application, the volatile component evaporates leaving behind the desired quantity of binder Types of Cutbacks Rapid Curing (Naphtha/Gasoline - Solvent) RC70, RC250, RC800 and RC3000 Medium Curing (Kerosene - Solvent) MC30, MC70, MC250, MC800, MC3000 Slow Curing (Diesel/Lubricating oil - Solvent) SC70, SC250, SC800, SC3000

85. E mulsions Two-phase system consisting of bitumen(50-75%), water, and one or more emulsifiers(0.1-2%) Bitumen is dispersed throughout the water phase in the form of discrete globules Used in pavement applications from 1920 In India, about 3% of bitumen is used in the form of Emulsions. Applications: Surface Treatments (Sealing, Microsurfacing ) Recycling (Cold-in-place) Other applications (Patching, Tack coat, Seal coat, Prime coat, Crack filling, Surface dressing, dust palliative, bituminous mixes, soil stabilization)

86. Emulsion - Classification Based on electric charge surrounding the globules, Anionic ( suitable for Calcareous aggregates) Cationic (Mostly used, Siliceous aggregate) Non-ionic (Rarely used) Based on how quickly emulsion reverts back to bitumen, Rapid Setting (Surface dressing, Patch repair) RS1 – Tack coat, RS2 – Surface dressing Medium Setting (Premix with lesser fines) MS – Open Graded Premix Slow Setting (Premix with larger % fines) SS1 – Priming, Fog seal, Crack seal, SS2 – Slurry sealing, Seal coat

87. Tests on Cutbacks and Emulsion ASTM D402/D402M–14:Standard Test Method for Distillation of Cutback Asphalt ASTM D3143-13: Standard Test Method for Flash Point of Cutback Asphalt with Tag Open-Cup Apparatus ASTM D3666-16: Standard Specification for Minimum Requirements for Agencies Testing and Inspecting Road and Paving Materials. ASTM D3910-11 : Standard Practices for Design, Testing, and Construction of Slurry Seal. ASTM D6934-08: Standard Test Method for Residue by Evaporation of Emulsified Asphalt ASTM D6930-10: Standard Test Method for Settlement and Storage Stability of Emulsified Asphalts ASTM D6997-12: Standard Test Method for Distillation of Emulsified Asphalt ASTM D7403-09: Standard Test Method for Determination of Residue of Emulsified Asphalt by Low Temperature Vacuum Distillation ASTM D7497-09: Standard Practice for Recovering Residue from Emulsified Asphalt Using Low Temperature Evaporative Technique

88. Modified Binders