Pavement Materials. Soil Aggregates Bitumen Cement. Recycled Materials Geosynthetics

Transcription

1 Pavement Materials Dr. S. Raviraj Professor of Civil Engineering JSS Science and Technology University Sri Jayachamarajendra College of Engineering Mysuru ravirajs@sjce.ac.in 31 st August, 2017

2 Pavement Materials Soil Aggregates Bitumen Cement e e Recycled Materials Geosynthetics Etc

3 Why Testing of Pavement Materials? To ensure quality during construction Conforms with appropriate standards. To understand the behavior of the materials individually and in combination with other materials

4 Why Testing of Pavement Materials? Characterization of materials Purpose To classify / Grade To obtain necessary inputs for design of new pavement To ensure proper quality during construction To obtain inputs regarding the condition of materials in an existing pavement

5 Pavement Material Aggregates

6 Aggregates Major component road construction. Aggregates have to bear stresses occurring due to the wheel loads on the pavement. On the surface course aggregates also have to resist wear due to abrasive action of traffic.

7 Aggregates are used in Pavement construction in Cement concrete, Bituminous concrete and other Bituminous constructions Granular base course underlying the superior pavement layers Hence, properties of the aggregates are of considerable significance to the highway engineers.

8 Types of Aggregates Natural aggregates Obtained from rock Artificial aggregates Slag (metallurgical process)

9 Origin of Aggregates Gravel aggregates are small rounded stones of different sizes which are generally obtained as such from some river beds. Aggregates are obtained from weathering or crushing of rocks. The properties of the coarse aggregates depend on the properties of parent rock. The properties of the rock depends on the constituent materials and the nature of bond between them.

10 Natural Aggregates Three Types Igneous rocks Sedimentary rocks Metamorphic rocks

11 Igneous rocks Cooling of molten magma Predominantly crystalline Volcanic rocks (Extrusive) Fine grained minerals Plutonic rocks (Intrusive) Coarse grained minerals

12 Igneous rocks Classification based on grain size Coarse ( > 2mm) Medium (2mm to 0.2mm) Fine ( < 0.2mm)

13 Igneous rocks Classification based on composition Acid rocks ( > 66% silica, light in colour & specific gravity < 2.75) Intermediate rocks (55 to 66% silica) Basic rocks ( < 55% silica, dark in colour & specific gravity > 2.75)

14 Igneous rocks Granite Basalt (Trap) Hard and durable Resistant to abrasion Low absorption of water Fine grained to coarse grained texture Very good for bituminous courses and cement concrete pavements

15 Sedimentary rocks Formed either from the deposition of insoluble granular material resulting from the disintegration of pre-existing rocks, or inorganic remains of marine and animals deposited in great quantities on the sea floor. Sedimentary rocks are deposited in layers, they have stratified or laminated structure.

16 Sedimentary rocks Classification based on predominating mineral: Calcareous rock (Chalk, Lime stone & Dolomite) Siliceous rock (Sand stone, Flint & Chert) Argillaceous (Clay & Shale)

17 Sedimentary rocks Limestone Sandstone Reasonably hard and durable Liable to a smooth polish Fine grained High absorption of water

18 Kankar Sedimentary rocks Soft to medium hard Good for sub-base and base courses

19 Metamorphic rock These are sedimentary or igneous rocks that have been subjected to great heat or great pressure or both, which has resulted in the formation of minerals and in textures different from those of the original rock.

20 Quartzite Metamorphic rock Reasonably hard and durable Resistant to abrasion Low absorption of water Fine grained to medium grained texture Good for base courses, bituminous courses and cement concrete pavements

21 Metamorphic rock Classification based on grain size: Fine grain size Hornfels & Schist Coarse grain size Gneiss & Granulite

22 Classification of Aggregates Based on strength property Hard aggregates Soft aggregates Classification based on shape, texture and gradation

23 Requirements of Aggregates They must be crushed aggregates. They shall be clean, hard, durable and cubical in shape. They must be free from the dust, organic matter and other deleterious matter. They must not be flaky or elongated.

24 Requirements of Aggregates They must not consist of harmful materials since they reduce the strength of pavements. They should resist wear due to abrasive action of traffic on the surface course.

25 Desirable Properties Strength Hardness Toughness Durability Shape Adhesion with bitumen

26 Strength Aggregates - Sufficiently strong to withstand the stresses due to traffic wheel loads. Aggregates used in top layer of the pavements, particularly in wearing course have to be capable of withstanding high stresses in addition to wear and tear. Crushing strength test

27 Hardness The aggregates used in the surface course are subjected to constant rubbing or abrasion due to moving traffic. They should be hard enough to resist the wear due to abrasive action of traffic.

28 Hardness Abrasive action may be increased due to the presence of abrasive material like sand between the tyres of moving vehicles and the aggregates exposed at the top surface. This action may be severe in the case of steel tyred vehicles.

29 Hardness Heavy wheel loads can also cause deformations on some types of pavement resulting in relative movement of aggregates and rubbing of aggregates (attrition) with each other within the pavement layer. However attrition will be negligible or absent in most of the pavement layers.

30 Hardness Abrasion Continuous wear and tear under the wheels of vehicles Attrition Rubbed with each other due to application of traffic load Hardness tests Los Angeles abrasion test Deval abrasion test Polished stone test

31 Toughness Aggregates in the pavements are also subjected to impact due to moving wheel loads. Severe impact like hammering is quite common when heavily loaded steel tyred vehicles move on water bound macadam roads where stones protrude out especially after the monsoons.

32 Toughness Jumping of the steel tyred wheels from one stone to another at different levels causes severe impact on the stones. The magnitude of impact would increase with the roughness of the road surface, the speed of the vehicle and other vehicular characteristics. Aggregates - ability to sustain impact loading Impact test

33 Durability The stone used in the pavement construction should be durable and should resist disintegration due to the action of weather. The property of the stones to withstand the adverse action of weather may be called soundness. Soundness Test

34 Shape of Aggregates The size of the aggregates is first qualified by the size of square sieve opening through which an aggregate may pass. Based on the shape of the aggregate particle, stones may be classified as rounded, angular, flaky and elongated. Aggregates in a particular size range may have rounded, cubical, angular, flaky or elongated shape of particles.

35 Shape of Aggregates It is evident that the flaky and elongated particles will have less strength and durability when compared with cubical, angular or rounded particles of the same stone. Hence too flaky and too elongated aggregates should be avoided as far as possible.

36 Shape of Aggregates The voids present in a compacted mix of coarse aggregates depend on the shape factors. Highly angular, flaky and elongated aggregates have more voids in comparison with rounded aggregates.

37 Shape of Aggregates Angular particles possess well-defined edges formed at the intersection of roughly plane faces and are commonly found in aggregates prepared by crushing of rocks. Flaky aggregates have lesser thickness when compared to the length and width. Elongated aggregates have one of the dimensions or the length higher than the width and thickness.

38 Shape of Aggregates The shape of aggregates depends on the source, properties of the rock and the type and condition of the crushers. The shape of aggregates is generally described in terms of its shape factors such as flakiness index, elongation index and angularity number.

39 Shape of Aggregates Several researchers have indicated that in pavement construction flaky and elongated aggregates are to be avoided, particularly in surface course. If flaky and elongated aggregates are present in appreciable proportions, the strength of the pavement layer would be adversely affected due to possibility of breaking down during compaction and under loads.

40 Shape of Aggregates Several researchers have indicated that in pavement construction flaky and elongated aggregates are to be avoided, particularly in surface course. If flaky and elongated aggregates are present in appreciable proportions, the strength of the pavement layer would be adversely affected due to possibility of breaking down during compaction and under loads.

41 Shape of Aggregates Desirable shape Angular or rounded Shape tests flakiness index, elongation index, angularity number

42 Adhesion with Bitumen The aggregates used in bituminous pavements should have less affinity with water when compared with bituminous material; otherwise the bituminous coating on the aggregates will be stripped off in presence of water. Stripping test

43 Tests on Road Aggregates Type of Test Aggregate Impact Test Los Angeles Abrasion Test Aggregate Crushing Test Soundness/Durability/ Accelerated weathering test Shape test: Flakiness Index, Elongation Index and Angularity Number Specific gravity Test Water absorption Test Property Evaluated Toughness or resistance to impact Hardness or resistance to abrasion Strength or resistance to crushing Durability or resistance to weathering To measure the quality or strength of material To measure the quality or strength of material To measure the porosity

44 Property Particle size distribution Plasticity Index Codes of Practice Code IS 2386 part 1 IS 2720 part 5 Water absorption & Bulk SG IS 2386 part 3 Flakiness and Elongation IS 2386 part 1 Mechanical Properties Impact, Abrasion, Crushing IS 2386 part 4 Soundness IS 2386 part 5 Presence of deleterious materials Bitumen coating & Stripping IS 2386 part 2 IS 2720 part 3 IS 6241 Water sensitivity test AASHTO T 283

45 Aggregate Impact Value Apparatus IS sieves (12.5, 10.0 and 2.36 mm) Cylindrical measure Cylindrical cup Weighing balance Tamping rod

46 Aggregate Impact Value

47 Aggregate Impact Value 15 Blows

48 Aggregate Impact Value Weight of aggregates taken = W1 Weight of aggregates retained on 2.36 mm sieve = W2 Weight of aggregates passing through 2.36 mm sieve = W3 Difference of W1 (W2 + W3) Aggregate Impact Value = W2/W1 x 100

49 Aggregate Impact Value < 10 % Exceptionally strong % Strong % Satisfactory for road surfacing > 35 % Weak for road surfacing AIV should not normally exceed 30% for aggregate to be used in wearing course of pavements. The maximum permissible value is 35% for bituminous macadam and 40% for water bound macadam base courses.

50 Aggregate Crushing Value Apparatus Steel cylinder with open ends and a square plate Plunger with piston Cylindrical measure Weighing balance IS sieves 12.5, 10 & 2.36 mm Steel Tamping Rod Compression testing machine

51 ACV - Process

52 Aggregate Crushing Value

53 Aggregate Crushing Value - Process Compressive load 40 tonnes

54 Aggregate Crushing Value Weight of aggregates taken = W1 Weight of aggregates retained on 2.36 mm sieve = W2 Aggregate Crushing Value = W2/W1 x 100

55 Aggregate Crushing Value IRC and BIS specify that the ACV for cement concrete pavement should not exceed 30 percent. For aggregates used for concrete other than for wearing surfaces, the ACV shall not exceed 45 percent.

56 Los Angeles Abrasion Test Apparatus Los Angles Abrasion M/c Steel balls - 11no. Weighing balance IS Sieves: 20, 12.5, 10 & 1.7mm

57 Los Angeles Abrasion Test Take 2.5 kg of given aggregates in sieve size mm Take 2.5 kg of given aggregates in sieve size mm Total weight of aggregates W1 = = 5kg

58 Los Angeles Abrasion Test

59 Los Angeles Abrasion Test Rotate the drum for 100 revolutions Wt. of aggregates retained on sieve 1.7 mm = W2 Los Angles Abrasion value= (W1-W2)/W1 x 100 %

60 Los Angeles Abrasion Test The Los Angeles abrasion value of good aggregates acceptable for cement concrete, bituminous concrete and other high quality pavement materials should be less than 30%. Values up to 50% are allowed in base courses like water bound and bituminous macadam.

61 Shape Tests Equi-dimensional aggregates Flat Aggregates Elongated Aggregates

62 Shape Tests Flat Aggregates Flakiness Index Elongted Aggregates Elongation Index Equi-dimensional Aggregates Angularity Number

63 Flakiness Index Apparatus Thickness gauge Weighing balance IS Sieves of sizes 63, 50, 40, 31.5, 25, 20, 16, 12.5, 10 and 6.3 mm Flakiness Index of aggregate is the percentage by weight of particles whose least dimension [thickness] is less than three- fifths [0.6] times of their mean size The test is not applicable to aggregates smaller than 6.3 mm

64 Flakiness Index

65 Flakiness Index A minimum of 200 pieces of first fraction to be tested are taken and weighed = W1 g The flaky aggregates passing through the respective openings are collected and weighed = w1 g

66 Flakiness Index The procedure is repeated for other fractions having weights W2, W3, etc. and the flaky aggregates in them having weights w2, w3 respectively are weighed. (w1+w2+w ) Flakiness Index = x 100 (W1+W2+W )

67 Elongation Index Apparatus Length gauge Weighing balance IS Sieves of sizes 63, 50, 40, 31.5, 25, 20, 16, 12.5, 10 and 6.3 mm Elongation Index of aggregate is the percentage by weight of particles whose greatest dimension [length] is more than nine - fifths [1.8] times of their mean size The test is not applicable to aggregates smaller than 6.3 mm

68 Elongation Index

69 Elongation Index A minimum of 200 pieces of first fraction to be tested are taken and weighed = W1 g The elongated aggregates not passing through the respective openings are collected and weighed = w1 g

70 Elongation Index The procedure is repeated for other fractions having weights W2, W3, etc. and the elongated aggregates in them having weights w2, w3 respectively are weighed. (w1+w2+w ) Elongation Index = x 100 (W1+W2+W )

71 Angularity Number The angularity number of an aggregate is the amount by which the percentage voids exceeds 33, after being compacted in a prescribed manner. The angularity number is found from the expression ( * W / C * G) %

72 Angularity Number Apparatus A metal cylinder closed at one end having 3 litre capacity (diameter and height approximately equal) A metal tamping rod, 16 mm in diameter and 600 mm long. Weighing balance IS sieves 25, 20, 16,12.5, 10, 6.3 and 4.75 mm

73 Angularity Number Procedure The sieves for each fraction (as specified) are arranged such as mm, etc. The given sample of aggregate is sieved so that sufficient pieces are obtained in each fraction. The empty cylinder is accurately weighed = a Each aggregate fraction is separately filled in the cylinder in 3 (three) layers tamping each layer 100 (hundred) times with the rounded end of tamping rod. The excess aggregate are removed.

74 Angularity Number Procedure The cylinder along with aggregate is weighed = b The aggregate are removed from the cylinder. The cylinder is completely filled with water and after wiping its outer sides it is weighed with water = c Angularity number = W / C * G W= Wt. of aggregate, C = Wt. of water and G= Specific gravity of aggregate

75 Shape Tests It is desirable that the flakiness index of aggregates used in road construction is less than 15% and normally does not exceed 25%. Elongation index value in excess of 15% is considered undesirable. Combined Flakiness and Elongation Index shall not exceed 40 %

76 Soundness To study the resistance of aggregates to weathering action, by conducting accelerated weathering test cycle. Apparatus Sodium sulphate or Magnesium sulphate Oven Weighing balance IS sieves

77 Soundness Procedure In order, to accelerate the effects of weathering due to alternate wet-dry or freezethaw cycles in the laboratory, the resistance to disintegration of aggregate is determined by using saturated solution of sodium sulphate or magnesium sulphate.

78 Soundness Procedure Clean, dry aggregates of specified size is weighed and counted. Then immersed in the saturated solution of sodium sulphate or magnesium sulphate for 16 to 18 hours. Then the aggregates are dried in an oven at C to a constant weight, thus making one cycle of immersion and drying.

79 Soundness Procedure The number of such cycles is decided by prior agreement and then the specimens are tested. After completing the final cycle, the sample is dried and each fraction of aggregate is examined visually to see if there is any evidence of excessive splitting, crumbling or disintegration of the grains.

80 Soundness Before After

81 Soundness As per IRC, 12% is the maximum permissible loss in soundness test after 5 cycles with sodium sulphate, for the aggregate to be used in bituminous surface dressing, penetration macadam and bituminous macadam constructions

82 Coarse Aggregate Specific Gravity Apparatus Density basket Weighing balance Water tank Tray IS sieves - 10mm & 20mm

83 Coarse Aggregate Specific Gravity

84 Coarse Aggregate Specific Gravity

85 Adhesion with Bitumen Static immersion test - Very commonly used as it is quite easy and simple. The principle of this type of test is by immersing aggregate fully coated with the binder in water maintained at specified temperature and time and by estimating the degree of stripping.

86 Adhesion with Bitumen The result is reported as the percentage of stone surface that is stripped off after the specified time period. IRC has specified the maximum stripping value as 25 % for aggregate to be used in bituminous construction like surface dressing, penetration macadam, bituminous macadam and carpet when aggregate coated with bitumen is immersed in water bath at 40 C for 24 hours.

87 Polished Stone Value Test Apparatus Accelerated polishing m/c Pendulum type friction tester Abrading material (sand and emery powder) IS sieves: 10, 8, 0.425, 0.3, & 15mm Mould of size 90.5 mm x 44.5 mm

88 Accelerated Polishing Machine Wheel Load = 40 kg Rotation of Load wheel = 320 to 325 rpm. Period of test = 3 hours

89 Accelerated Polishing Machine The machine is operated for a further period of 3 hours after releasing emery powder and water at the specified rates (instead of sand). The machine is stopped and test specimens and machine are cleaned.

90 Polished Stone Value Sample Preparation

91 PSV Sample

92 PSV Polishing

93 PSV Skid Tester (Friction Tester) Pointer reading: Polished stone value or skid number or friction coefficient in percent

94 Polishing Stone Value For road and bridge works, the polished stone value of coarse aggregates used in bituminous concrete, semi dense bituminous concrete, open graded pre-mix carpet and close graded premix surfacing of roads, should be not less than 55 and for the aggregate used in surface dressing should be not less than 60.

95 Splitter

96 Sieve Set

97 Sieve Analysis Analisis Ayakan Percent Passing, % Sieve Size, mm

98 Pavement Material Bitumen

99 Pavement Construction

100 Bituminous Materials Binder: A material used to hold solid particles together, i.e. bitumen or tar. Bitumen: A heavy fraction from oil distillation or Last residue obtained from fractional distillation of Crude Oil. Also occurs as part of natural asphalt.

101 What is Bitumen? Is a visco-elastic material Does not have a distinct melting point Gradually softens when heated More solid at low temperatures and more liquid at high temperatures Is black or dark brown in colour Has adhesive properties Has water proofing properties Forms good bond with variety of aggs.

102 Natural / Rock / Lake Asphalt Naturally occurring Bituminous binder Biggest deposits in Trinidad 100 Acres 90 meter deep 10 to 15 Million MT Pen - 5 max Asphalt is found in France, Italy and Switzerland - Rock Asphalt.

103 Binder Materials Tar: A viscous liquid obtained from distillation of coal or wood. Rarely used in road construction. Coke Oven Tar Produced at temperatures above 1200 O C during manufacturing of coke High aromatic content Pitch content - 50 %

104 Binder Materials Low Aromatic Tar Produced at temperatures 600 O C to 700 O C Less viscous Paraffinic in nature Pitch content - 35 %

105 Cutbacks This is a liquid form of bitumen. They are liquid at low temperatures until the volatile oil evaporates. Due to the release of solvents into the atmosphere they are now rarely used.

106 Emulsions When bitumen globules are mixed with water, binders will generally settle out. An emulsifier must be added to give a stable solution. When used, the water evaporates and the bitumen remains on the surface. The current types of cold rolled materials are based on emulsions.

107 Binder Properties Adhesion: Bituminous materials adhere to clean dry surfaces Viscosity: All bituminous materials are viscous, i.e. when subject to a long term load they deform continuously Softening point: This is the temperature at which the binder softens to a predetermined point

108 Performance Parameters of Binders Mix and form a good bond with aggregate (at high temperature) Not melt on the road at highest atmospheric temperature Not crack at extreme low atmospheric temperature Be able to withstand repeated cycles of loading and unloading

109 Performance Parameters of Binders Be able to withstand repeated cycles of temperature change Not be inflammable Be free from impurities

110 Description of Bitumen Bitumen shall be prepared by the refining of crude petroleum by suitable methods using appropriate crude or by blending different crudes or different short residue to achieve desired properties of paving grade bitumen conforming to specifications.

111 What type of tests do we develop? Tests should be simple Tests should replicate the actual field conditions as accurately as possible Rate of change of properties with time, temperature and load should be measurable or predictable

112 Tests on Bitumen 1. Penetration test 2. Softening point test 3. Ductility test 4. Viscosity test 5. Specific gravity test 6. Flash and Fire point test 7. Solubility test 8. Thin film oven test

113 Arbitrary Empirical Number Penetration Test Depth of penetration of a standard size needle under standard test conditions An indirect method of measuring viscosity The test measures the hardness or softness of bitumen in terms of penetration

114 Penetration test Bitumen is softened to a pouring consistency and is poured into the container to a depth at least 10 mm in excess of the expected penetration. The penetration sample is cooled for 90 min in air (15 to 30 0 C) and then for 90 min in water bath (25 0 C) before testing.

115 Penetration Test Temperature = 25 0 C Load on needle = 100 g Time in which penetration is recorded = 5 s The penetration is measured by a graduated dial (in 1/10th of mm)

116 Penetration test A bitumen is referred to as 70 pen if the penetration is 7 mm. A grade of 40/50 bitumen means the penetration value is in the range 40 to 50 at standard test conditions.

117 Penetration test In cold regions, bitumen with High penetration value is used. In warm regions, bitumen with low penetration value is used ex. 30/40 grade. The factors which affect the Penetration test is test temperature, needle size and weight and period of cooling.

118 Softening Point Test Ring and ball apparatus

119 Softening Point Test The softening point is the temperature at which the substance attains a particular degree of softening under specified condition of test. A viscous material like bitumen or tar doesn t have a well defined softening point. The test determines the temperature at which a standard ball will pass through a disc of bitumen contained in ring.

120 Softening Point Test Arbitrary test to indicate the temperature at which bitumen is more of a liquid and less of a solid

121 Softening Point Test Brass rings Inside dia 17.5 mm at top 15.9 mm at bottom Outside dia 20.6 mm Depth 6.4 mm Steel balls Dia 9.5 mm and mass 3.5 g Distance between bottom of the ring and top surface of the bottom plate is 25mm

122 Softening Point Test Glass container Dia 85 mm Depth 120 mm The bitumen is heated to pouring consistency and poured into ring and cooled for half an hour before testing.

123 Softening Point Test Arrrangement Specimen in steel rings Steel Balls in Ball Guides Water or Glycerin

124 Softening Point Test The liquid medium is then heated at a rate of 5 0 C increase per minute. With increase in temperature bitumen melts and come down with the weight of ball The temperature at which the steel balls touches the bottom plate is noted

125 Softening Point test Higher softening points indicate higher resistance to melting on pavement. Higher resistance to melting indicates higher rutting resistance. Higher softening point indicates lower temperature susceptibility and is preferred in warm climates.

126 Ductility Test In flexible pavement construction it is important that the binders form ductile thin film around the aggregate. This serves as a satisfactory binder in improving the physical interlocking of the aggregate bitumen mixes. Under traffic loads the bitumen layer is subjected to repeated deformation and recoveries.

127 Ductility Test The binder material which does not possess sufficient ductility would crack and thus provide pervious pavement surface. The test is believed to measure the adhesive property of bitumen and its ability to stretch. The ductility of a binder is an indication of its elasticity & ability to deform under load & return to original condition upon removal of the load.

128 Ductility Test A material which doesn t possess adequate ductility would crack under a load. This is unsatisfactory since water can penetrate into the surfacing through there cracks. The property is determined by conducting the ductility test using a standard briquette of bitumen.

129 Ductility Test Briquette mould

130 Ductility Test The briquette mould is filled with bitumen and cooled for 30 min in air and 30 min in water before testing.

131 Ductility Test Then it is fixed to expanding machine assembly which stretches the bitumen at a rate of 5cm/min

132 Ductility Test The stretching is continued and the bitumen specimen expands till it breaks. This point is noted by the reading on the scale.

133 Ductility Test Ductility is defined as the distance that a standard briquette of bitumen, necked to a cross section of 1 sq-cm, will stretch without breaking when elongated at a rate of 5 cm/min at 27 0 C. Minimum ductility value - 50 cm as per IS.

134 Viscosity Test Viscosity is the property of a fluid that determines the resistance offered by the fluid to a shearing force under laminar flow conditions, it is thus the opposite of fluidity. At the application temperature, viscosity greatly influences the strength of resulting paving mixes.

135 Viscosity Test Low or high viscosity during mixing or compaction has been observed to result in lower stability values. At high viscosity, it resists the compactive effort and thereby resulting mix is heterogeneous, hence low stability values. At low viscosity instead of providing a uniform film over aggregates, it will lubricate the aggregate particles.

136 Viscosity Test Absolute or Dynamic Viscosity Kinematic Viscosity Viscosity Ratio

137 Viscosity Test Absolute or Dynamic Viscosity (Newtonian Liquid) It is an internal friction, such that if a tangential force of one dyne ( N) acting on planes of unit area separated by unit distance of the liquid produces unit tangential velocity, the CGS unit for the viscosity of the liquid is 1 Poise.

138 Viscosity Test Viscometer - Capillary type made of borosilicate glass, annealed suitable for this test Cannon-Manning Vacuums Viscometer e Asphalt Institute Vacuum Viscometer Modified Koppcrs Vacuum Viscometer

139 Cannon-Manning Vacuums Viscometer The size numbers/approximate bulb factors K, and viscosity ranges are as follows:

140 Cannon-Manning Vacuums Viscometer For all viscometer sizes the volume of measuring bulb C is approximately three times that of bulb B. The viscosity ranges correspond to a filling time of 60 and 400 s for both measuring bulbs.

141 Cannon-Manning Vacuums Viscometer Water Bath A suitable water bath for immersion of the viscometer so that the liquid reservoir or top of the capillary, whichever is uppermost is at least 20 mm below the upper bath level, and with a provision for the visibility of the viscometcr and the thermometer. Firm support for the viscomrter shall be provided. The accuracy of the viscometer bath should be ± C over the entire length of the viscometer.

142 Cannon-Manning Vacuums Viscometer Vacuum System A vacuum system capable of maintaining a vacuum to within ± 0.05 cm of the desired level up to and including 30 cm of mercury. The glass tubing of 6.35 mm diameter and all glass joints should be completely airtight and no loss of vacuum should be permitted till the experiment is on. A vacuum or aspirator pump is suitable for the vacuum source.

143

144 Cannon-Manning Vacuums Viscometer Procedure Conduct similar test on the sample and find the value of time t. Calculate the absolute viscosity to three significant figures, by the following equation: Viscosity Poises = K t Where K = selected calibration factor, in poise per second; and t = flow time in seconds

145 Cannon-Manning Vacuums Viscometer Always report the test temperature and vacuum with the viscosity test results. For example, viscosity at 6O 0 C, 30 cm Hg Vacuum in poises

146

147 Cannon-Manning Vacuums Viscometer Kinematic Viscosity The CGS unit of kinematic viscosity is the stoke which has the dimensions square centimetre per second. For petroleum products the kinematic viscosity is generally expressed in centistokes (cst) which is l/looth of a stoke.

148 Cannon-Manning Vacuums Viscometer Viscosity Ratio It is the ratio of viscosity of residue from rolling thin film oven test to unaged bitumen, both measured at 60 C.

149 Specific Gravity Test Specific gravity value is required for conversion of weight to volume. Specific gravity of a binder is needed during mix proportioning. SG of bitumen varies from 0.97 to SG of tar varies from 1.16 to 1.28.

150 Specific Gravity Test There are two methods to test the specific gravity of bitumen Pyknometer method Balance method Generally balance method is used Cubical specimens of side 20 mm are used to find the SG.

151 Specific Gravity Test The mass of the dry specimen when cooled at 27 0 C is noted a. The mass of the speciment when immersed in distilled water is noted b. Specific gravity of bitumen = a/(a-b) High value of specific gravity suggests impurity in bitumen.

152 Flash and Fire Point Test When a bituminous binder is heated continuously it starts emitting volatile vapours (hazardous) above a certain temperature. These volatile vapours can momentarily catch fire in form of flash and on continued heating will catch fire.

153 Flash and Fire Point Test It is essential that the bitumen qualifies these temperatures before use. The flash point of bitumen is that temperature at which it gives off vapours, which ignite when exposed to flame, but does not continue to burn. The flash point is an indication of critical temperature at & above which suitable precautions should be taken to eliminate fire hazards.

154 Flash and Fire Point Test Pensky-Mortins Tester - BIS. The method involves a cup into which the bitumen is filled. The bitumen sample is then heated at a rate of C/min stirring the material continuously. The surface is exposed to test flame at regular intervals.

155 Flash and Fire Point Test The flash point is taken at the temperature read on the thermometer when flame causes a bright flash on the surface of material. It is in the range of C.

156 Flash and Fire Point Test If heating is continued beyond the flash point, the vapours ignite in the presence of the flame and will continue to burn. Fire point is that temperature at which the surface catches file and burns continuously for five seconds. The presence of water will spread the bitumen fire.

157 Solubility Test All bitumen are substantially soluble in Carbon-di-sulphide and Carbon tetra chloride. Hence any impurity in bitumen in the form of inert minerals, carbon, salts etc. could be quantitatively analysed by dissolving the samples of bitumen in any one of the two solvents.

158 Solubility Test A sample of 2g of bitumen is dissolved in 100 ml of solvent and filtered. The insoluble material is washed, dried and weighed. It is expressed in percentage of original sample. The IS specifications require 99% solubility.

159 Thin Film Oven Test Oven Tester

160 Thin Film Oven Test A sample of bitumen is subjected to hardening conditions as would be expected during hot mixing operations. A 50 ml sample of bitumen is placed in a flat bottomed sample pan 140mm inside diameter & 10mm deep, the weighed sample & container are placed in a shelf which rotates at 5 to 6 rpm for 5 hrs in a ventilated oven maintained at C.

161 Thin Film Oven Test 3 Containers 140 mm dia 10 mm deep 1 Shelf 5 to 6 rpm 5 hrs C

162 Thin Film Oven Test The loss in weight of the sample is expressed as percentage of the original weight. This method is used to identify short term aging or hardening of bitumen.

163 Rolling Thin Film Oven Test To simulate the short-term aging of asphalt binders that occurs during the hot-mixing process. Use this test to calculate the change in sample mass on heating, but its main function is to produce an aged material for analysis by other suitable means.

164 Rolling Thin Film Oven Test Apparatus Rolling thin film oven (RTFO), with a flow meter and thermometer Eight sample containers (RTFO bottles) Balance Spatula or other tool, sufficiently shaped to scrape material from the inside of the RTFO bottles Sample dishes, tins, or cups, for collecting aged material at the end of the test.

165 Rolling Thin Film Oven Test

166 Rolling Thin Film Oven Test

167 Rolling Thin Film Oven Test Key Parameters Position of air nozzle outlet from the mouth of sample containers 6.4 mm Position the thermometer so that its bulb is with 25 mm of the same height as the center of the carriage Time 85 ± 5 min Temperature 163 ± 0.5 C Rotation speed of the carriage 15 ± 0.2 rpm Air flow to the oven 4 ± 0.2 L/min

168 Rolling Thin Film Oven Test Procedure Heat the asphalt binder sample to 163 C in a oven until it is completely fluid and pourable Remove the sample from the oven and briefly stir with a clean spatula If measuring mass change, weigh the two empty mass-change bottles to the nearest g and record the results

169 Rolling Thin Film Oven Test Procedure Pour 35 ± 0.5 g of asphalt into a sample bottle Place the bottle on its side and roll it over to spread the material around the inside Repeat the above procedure for the second bottle Set the mass-change bottles aside and allow them to cool

170 Rolling Thin Film Oven Test Procedure Pour 35 ± 0.5 g of asphalt into a sample bottle Place the bottle on its side and roll it over to spread the material around the inside Repeat the above procedure for all other samples When the mass-change bottles have cooled, weigh to the nearest g

171 Rolling Thin Film Oven Test Procedure Load the sample bottles in the sample carriage as soon as possible after pouring Start the test within 5 min. of loading the samples into the carriage and evenly distribute all bottles around the carriage If measuring mass change, remove the previously weighed bottles from the oven, and place them on their sides to cool down

172 IS 73 : 2013 PAVING BITUMEN SPECIFICATION Viscosity Ratio It is the ratio of viscosity of residue from rolling thin film oven test to unaged bitumen, both measured at 60 C. GRADES of Bitumen Bitumen shall be classified into four grades based on the viscosity, and suitability recommended for maximum air temperature.

173 IS 73 : 2013 PAVING BITUMEN SPECIFICATION Grade Suitable for 7 day Average Maximum Air Temperature C VG10 < 30 VG VG VG40 > 45 NOTE This is the 7 day average maximum air temperature for a period not less than 5 years from the start of the design period.

174 IS 73 : 2013 PAVING BITUMEN SPECIFICATION REQUIREMENTS The paving bitumen binder shall be homogenous and shall not foam when heated to 175 C. The various grades of bitumen shall conform to the requirements prescribed in Table 1 of IS 73.

175 IS 73 : 2013 PAVING BITUMEN SPECIFICATION Requirements for Paving Bitumen Penetration at 25 C, 100 g, 5 s, 0.1 mm, Min Grade Penetration VG10 80 VG20 60 VG30 45 VG40 35 Method of test - IS 1203

176 IS 73 : 2013 PAVING BITUMEN SPECIFICATION Requirements for Paving Bitumen Absolute viscosity at 60 C, Poises Grade Penetration VG VG VG VG Method of test - IS 1206 (Part 2)

177 IS 73 : 2013 PAVING BITUMEN SPECIFICATION Requirements for Paving Bitumen Kinematic viscosity at 135 C, cst, Min Grade Penetration VG VG VG VG Method of test - IS 1206 (Part 3)

178 IS 73 : 2013 PAVING BITUMEN SPECIFICATION Requirements for Paving Bitumen Kinematic viscosity at 135 C, cst, Min Grade Penetration VG VG VG VG Method of test - IS 1206 (Part 3)

179 IS 73 : 2013 PAVING BITUMEN SPECIFICATION Requirements for Paving Bitumen Solubility in trichloroethylene, percent, Min Grade Penetration VG VG VG VG Method of test - IS 1216

180 IS 73 : 2013 PAVING BITUMEN SPECIFICATION Requirements for Paving Bitumen Softening point (R&B), C, Min Grade Penetration VG10 40 VG20 45 VG30 47 VG40 50 Method of test - IS 1205

181 IS 73 : 2013 PAVING BITUMEN SPECIFICATION Requirements for Paving Bitumen Tests on residue from rolling thin film oven test: Viscosity ratio at 60 C, Max Grade Penetration VG VG VG VG Method of test - IS 1206 (Part 2)

182 IS 73 : 2013 PAVING BITUMEN SPECIFICATION Requirements for Paving Bitumen Tests on residue from rolling thin film oven test: Ductility at 25 C, cm, Min Grade Penetration VG10 70 VG20 50 VG30 40 VG40 25 Method of test - IS 1208

183 Modes of Failure

184 Rutting/ Permanent Deformation

185 Fatigue Cracking

186 Low Temperature Cracking

187 Cracking of thin surface

188 Thank you