TRANSPORTATION ENGINEERING

Practical Lab Manual

Submitted To: Submitted By:

Name: _________________ Name: _________________

Signature: ______________ Reg No: ________________

Section:________________

Department of Civil Engineering

COMSATS Institute of Information Technology (CIIT) Abbottabad

Highway Engineering Lab Manual

Dept. of Civil Engineering, CIIT, Abbottabad Page ii

OBJECTIVES

1. Provide a platform to undergraduate and graduate students for practical

implementation of Transportation Engineering projects.

2. Bring students to the level of industrial standards in field of

Transportation Engineering.

3. Provide a platform for integration of academics and research.

4. Enhancing ability of students to apply appropriate methods of analysis to

raw data deduced from experiments.

5. At the end of course students would be able to carry out testing

procedures correctly.

6. Significance of testing in the design and infrastructure of transportation

engineering projects.

Highway Engineering Lab Manual

Dept. of Civil Engineering, CIIT, Abbottabad Page iii

SAFETY PRECAUTIONS

Introduction

These notes with the safety precautions and safety measures that should be observed and

taken by all users of laboratory facilities. There will be special precautions needed for

handicapped people using laboratories, but these are outside the scope of this set of notes.

General Behavior

No smoking

No running, playing games, throwing objects or foolish behavior allowed.

Disciplinary actions will be taken against offenders

Safety precautions must be observed at all times

Observe any instructions or advice given by the laboratory staff

Do not attempt to install, correct or operate any apparatus before reading the

instructions, and if in doubt, seek the assistance of the laboratory staff.

Safety

General

Treat every piece of apparatus with caution

Beware of others working in the vicinity

Understand all safety precautions before working in the laboratories

If in doubt, ask for assistance

Electricity

Switch off and isolate the power supply before opening cabinet doors or attempting

to make any adjustment to the equipment

Check all the circuits before switching on the power supply

Do not tampers with any switches or protective gears

Beware of dangerous voltages developed during the course of using any item of

apparatus

Do not work on the electrical apparatus with wet hands

Special care should be taken when bare conductors are being used to carry any

current

Always switch off and isolate the service suppliers after using any apparatus.

Chemicals

Treat all chemicals with extreme caution

Use protective equipment when provided

Know the properties of chemicals before attempting to handle them

Alert others in the vicinity when handling poisonous, toxic, corrosive or explosive

substances.

Highway Engineering Lab Manual

Dept. of Civil Engineering, CIIT, Abbottabad Page iv

Machines

Do not operate any machines unless you have been trained to do so

Use protective equipment when provided.

Do not leave any machines in operation unattended

Switch off and isolate the machines when not in use.

Fire Hazards

Check for any possible danger of fire in the vicinity before producing any naked

flame

Clean up any spilled combustible fluids immediately

Extinguish all flames before refueling any equipment.

Handle inflammable substances with care

When a gas leak is suspected, extinguish all naked flames.

Ensure there is enough ventilation before starting any combustion process.

If the fire alarm sounds, evacuate from the laboratories immediately and assemble

at the ground floor lobby, unless there is a broadcast for other actions over internal

public address system.

Radiation Hazards

Use protective equipment when handling any radioactive substance.

Never leave any radioactive substance unattended.

Never transfer any radioactive substance without a proper protective container.

Security

Take care of your own valuables.

Do not remove any piece of equipment from the laboratories unless authorized to

do so.

Only enter and exit the laboratories through the established route.

Observe the directives given by the laboratory staff.

Do not attempt to enter or remain in the laboratory outside the opening hours.

Report any loss or damage to laboratory equipment immediately to laboratory staff.

Highway Engineering Lab Manual

Dept. of Civil Engineering, CIIT, Abbottabad Page v

Table of Contents

OBJECTIVES………………………………………………………………………………...……...ii

SAFETY PRECAUTIONS…………………….…………………………………………………....iii

EXPERIMENT NO: 01........................................................................................................................1

PENETRATION TEST OF BITUMEN (ASTM D 5-05)................................................................1

EXPERIMENT NO: 02........................................................................................................................4

DUCTILITY TEST OF BITUMEN (ASTM D 113-07) .................................................................4

EXPERIMENT NO: 03........................................................................................................................8

SOFTENING POINT TEST OF BITUMEN (ASTM D 36-95) ....................................................8

EXPERIMENT NO: 04.......................................................................................................................12

FLASH AND FIRE POINT TEST OF BITUMEN (ASTM D 92-12A) .......................................12

EXPERIMENT NO: 05......................................................................................................................14

STANDARD VISCOSITY TEST (ASTM D 2170M-10) .............................................................14

EXPERIMENT NO: 06......................................................................................................................18

EXTRACTION TEST OF BITUMEN (ASTM D 2172M-11)......................................................18

EXPERIMENT NO: 07......................................................................................................................20

PREPARATION OF JOB MIX FORMULA (AASHTO T 166-88.............................................20

EXPERIMENT NO: 08......................................................................................................................22

MARSHALL STABILITY AND FLOW TEST (ASTM D 6927-06) ..........................................22

EXPERIMENT NO: 09......................................................................................................................33

AGGREGATE IMPACT VALUE TEST (ASTM D 5874-02) ....................................................33

EXPERIMENT NO: 10......................................................................................................................35

AGGREGATE CRUSHING VALUE TEST (BS 812) .................................................................35

EXPERIMENT NO: 11......................................................................................................................37

LOS ANGELES ABRASION TEST (ASTM C 535-03) ..............................................................37

EXPERIMENT NO: 12......................................................................................................................40

SHAPE TEST FOR AGGREGATES (ASTM D 4791-10) ...........................................................40

EXPERIMENT NO: 13......................................................................................................................43

WATER ABSORPTION TEST OF AGGREGATES (ASTM C 127-12) ...................................43

EXPERIMENT NO: 14......................................................................................................................45

SPECIFIC GRAVITY OF COARSE AGGREGATES (ASTM C 127-12) ................................45

EXPERIMENT NO: 15......................................................................................................................49

CALIFORNIA BEARING RATIO (CBR) TEST (AASHTO T 193-81) ....................................49

EXPERIMENT NO 1 PENETRATION TEST OF BITUMEN

(ASTM D: 5-97)

1. Scope

The penetration of bitumen is defined as the distance in tenths of millimeter that a standard

needle vertically penetrates in a sample of bitumen under known conditions of loading, time

and temperature. (A load of 100 grams applied for 5seconds at 25C is standardized for the test)

A small penetration value indicates that the bitumen is hard, while the high penetration value

indicates that the bitumen is soft.

2. Standard

ASTM D: 5-97

3. Significance

This test is used to determine the penetration grade of

bitumen. The behavior of bituminous materials varies

significantly with change in temperature. It is therefore

important to use the appropriate grade of bitumen that is best

suitable for the climatic conditions of the project area.

4. Apparatus

4.1. Penetrometer with control box.

4.2. Container. 55 mm diameter and 35 / 70 mm

internal height. Should have flat bottom.

4.3. Water bath with at least 10 liter capacity.

4.4. Heater

4.5. Thermometer

4.6. Specified needle

4.7. Transfer tray

5. Procedure

5.1. Soften the bitumen by heating it up to 90C to bring it to pouring consistency. Stir the

bitumen while heating to avoid local overheating and to make it homogenous.

5.2. Pour the bitumen into container to a level that when cooled to testing temperature, depth of

bitumen should be at least 10 mm more than the expected depth of penetration.

5.3. Place the prepared sample at room temperature (15C - 30C) for one hour.

1

5.4. Place the container below the needle of penetrometer and gradually lower the needle to

make a contact with the bitumen. Ensure that the needle is just in contact with the sample

and no penetration is affected. Place a lamp on one side of the needle in such a way that it

creates a sharp shadow of needle on the sample. This will help in correct positioning of the

needle.

5.5. Press the push button of the control box to release the needle. The needle will penetrate the

sample under its own weight for 5 seconds and after that it will stop automatically. Note

down the reading.

5.6. Take at least three readings.

5.7. At least two samples should be tested for grade determination.

6. Calculation And Observation

6.1. Pouring temperature =

6.2. Period of cooling in room = 1hour

6.3. Room temperature =

6.4. Water bath temperature = 25o C

S No.

Penetration in 10th of (mm)

Grade Reading Reading Reading

1.

2.

7. Other Test Conditions. If required, the test can be performed under following set of

conditions

Temperature OC (F)

Load

Grams

Time

Seconds

0 (32) 200 60

4 (39.2) 200 60

45 (113) 50 5

46.1 (115) 50 5

8. Precautions

8.1. Overheating of bitumen should be avoided. Under no condition bitumen should be

heated to 60o C above the expected softening point.

8.2. The sample is covered loosely against dust

8.3. The weight of needle and spindle assembly should be accurate i.e, 100 ± 0.05 grams.

2

8.4. Verticality of the needle should be ensured.

8.5. Readings taken on a single sample should be at least 10 mm apart.

Practical Applications.

1.

2.

3.

3

EXPERIMENT NO 2 DUCTILITY TEST OF BITUMEN

(ASTM-D113-86)

1. Scope

The ductility of a bituminous material is measured by the distance to which it will elongate

before breaking when two ends of a briquette specimen of the material, of the form

described, are pulled apart at a specified speed and at a specified temperature. Unless

otherwise specified, the test shall be made at a temperature of 77+ 0.90F (25+0.50C) and

with a speed of 5 cm/min + 5.0%. At other temperatures the speed should be specified.

2. Standard

ASTM-D113-86

3. Significance

This test method provides one measure of tensile properties of bituminous materials and may

be used to measure ductility for specification requirements.

4. Apparatus

3.1. Mold – the mold shall be similar in design to that shown in fig. The mold shall be made

of brass, the ends b and b/ being known as clips and the parts a and a/ as sides of the

mold. The dimensions of the assembled mold shall be as shown in fig with the variations

indicated.

4

3.2. Water Bath – the water bath shall be maintained at the specified test temperature, varying

not more than 0.180F (0.10C) from this temperature. The volume of water shall not be

less than 10 liters and the specimen shall be immersed to a depth of not less than 10 cm

and shall be supported on a perforated shelf not less than 5 cm from the bottom of the

bath.

3.3. Testing Machine – For pulling the briquette of bituminous material apart, any apparatus

may be used which is so constructed that the specimen will be continuously immersed in

water as specified, while the two clips are pulled apart at uniform speed, as specified,

without undue vibration.

5

3.4. Thermometer – A thermometer having a range as shown below and confirming to the

requirements prescribed in specification.

Temperature Range ASTM Thermometer No

-8 to 320C 630C

18 to 890F 630F

Note: In those cases where the ductility specimens are aged in the standard penetration bath

at 770F (250C), the thermometer as prescribed for test method D-5 may be substituted in

place of the above.

5 Procedure

5.1 Assemble the mold on a brass plate. Thoroughly coat the surface of the plate and interior

surfaces of the sides a and a/, Fig, of the mold with a thin layer of a mixture of glycerin

and dextrin, talc or kaolin (china clay) to prevent the material under test from sticking.

The plate upon which the mold is placed shall be perfectly flat and level so that the

bottom surface of the mold will be in contact throughout.

5.2 Carefully heat the sample to prevent local overheating until it has become sufficiently

fluid to pour. Strain the melted sample through a sieve No 50 (300um) confirming to

specification. After a thorough stirring, pour it into the mold. In filling the mold, take

care not to disarrange the parts and thus distort the briquette. In filling, pour the material

in a thin stream back and forth from end to end of the mold until the mold is more than

level full. Let the mold containing the material cool to room temperature for a period of

30 to 40 min and then place it in the water bath maintained at the specified temperature of

test for 30 min, then cut of the excess bitumen with a hot straight edged putty knife or

spatula to make the mold just level full.

5.3 Keeping specimen at standard temperature. Place the brass plate and mold, with briquette

specimen, in the water bath and keep at the specified temperature for a period of 85 to 95

min. Then remove the briquette from the plate, detach the side pieces, and immediately

test the briquette.

5.4 Testing – Attach the rings at each end of the clips to the pins or hooks in the testing

machine and pull the two clips apart at a uniform speed as specified until the briquette

ruptures. A variation of + 5% from the speed specified will be permissible. Measure the

distance in cm through which the clips have been pulled to produce rupture. While the

test is being made, the water in the tank of the testing machine shall cover the specimen

both above and below it by at least 2.5 cm and shall be kept continuously to the

temperature specified within +0.90F (0.50C).

6 Observations and Calculations

Grade of Bitumen ……………………………

6

Pouring temperature………………………….

Test temperature……………………………..

Period of cooling in room……………………

Water bath temperature……………………

Test Specimen No

Mean value

1 2 3

Ductility value (cm)

7 Precautions

7.1 Carefully heat the sample to prevent local overheating.

7.2 Take care not to disarrange the parts and thus distort the briquette.

7.3 The water in the tank of the testing machine shall cover the specimen both above and

below it by at least 2.5 cm

7.4 Keep the water bath and the specimen at the specified temperature for the specified

period.

7.5 Pulling of the two clips apart should be at a uniform speed.

8 Practical Applications

1.

2.

3.

7

8

EXPERIMENT NO 3 SOFTENING POINT OF BITUMEN

(AASHTO T 53-89 & ASTM D 36 – 95, Reproved 2000)

1. Scope

This test method covers the determination of the softening point of bitumen in the range from

30 to 157oC (86 to 315oF) using the ring-and-ball apparatus immersed in distilled water (30 to

80oC), USP glycerin (above 80 to 157oC), or ethylene glycol (30 to 110oC). The softening

point is the temperature at which the substance attains particular degree of softening under

specified conditions of test.

2. Standard

AASHTO T 53-89 & ASTM D 36 – 95,

Reproved 2000

3. Significance

Softening point is actually a

consistency test and consists of heating of

bituminous material until they reach at the

given consistency.

4. Apparatus

4.1. Rings. Two square-shouldered brass rings conforming to the dimensions shown in the

figure

4.2. Pouring Plate. A flat, smooth, brass plate approximately 50 by 75mm (2 by 3in).

4.3. Balls. Two steel balls, 9.5mm (3/8in) in diameter, each having a mass of 3.50 + 0.05g.

4.4. Ball-Centering Guides. Two brass guides for centering the steel balls, one for each

ring, conforming to the general shape and dimensions shown in Figure.

4.5. Bath. A glass vessel, capable of being heated, not less than 85 mm in inside diameter

and not less than 120 mm in depth from the bottom of the flare.

4.6. Ring Holder and Assembly. A brass holder designed to support the two rings in a

horizontal position, conforming to the shape and dimensions shown in Figure,

supported in the assembly illustrated in Figure. The bottom of the shouldered rings

in the ring holder shall be 25mm (1in) above the upper surface of the bottom plate,

and the lower surface of the bottom plate shall be 16 ± 3mm (5/8 ± 1/8in) from the

bottom of the bath.

9

4.7. Thermometers

4.7.1. An ASTM Low Softening Point Thermometer, having a range from -2 to +

80°C or 30 to 180°F, and conforming to the requirements for Thermometer

15C or 15F as prescribed in Specification.

4.7.2. The appropriate thermometer shall be suspended in the assembly as shown in Figure

so that the bottom of the bulb is level with the bottom of the rings and within 13mm

(0.5in) of the rings, but not touching them or the ring holder. Substitution of

other thermometers shall not be permitted.

5. Procedure

5.1. Heat the bitumen until it comes to liquid form.

5.2. Fill the rings with bitumen and cool it to room temperature.

5.3. Assemble the apparatus with ring thermometer and place balls guide in position and fill

the bath to a depth of 4 to 4.25in.

5.4. Maintain the bath at a temperature of 4±1ºC for 15 minutes.

5.5. Place the balls on the surface of the specimen

5.6. Start the bath heater at a rate of 5ºC/ min and keep stirring as necessary.

5.7. Record the temperature when the balls pass in the rings and touch the bottom; this is the

softening point in centigrade.

5.8. The softening point to be reported as the mean of the temperatures at which the two

discs soften enough to allow each ball, enveloped in bitumen, to fall a distance of 25mm.

10

11

6. Observations and Calculations

Bitumen Grade ………………………

Period of air cooling = 1 hour

Rate of heating Rate of heating

Time (Minute) Temperature ºC Time (Minute) Temperature ºC

7. Precautions

7.1. Heat the sample with care.

7.2. The max temperature should not exceed 100oC.

7.3. Note the reading with care and raise the temperature at the rate of 5oC/minute.

8 Practical Applications

1.

2.

3.

12

EXPERIMENT NO 4 FLASH AND FIRE POINT OF BITUMEN

(AASHTO: T 48-89 and ASTM: D-92)

1. Scope

Different bituminous materials hav quite different values of flash and fire point When the

bitumen or cut back is to be heated before mixing or application utmost care is taken to see that

heating is limited to a temperature will below the flash point.

2. Standard

AASHTO: T 48-89 and ASTM: D-92

3. Significance

This flash-point and fire-point test method is

a dynamic method and depends on definite

rates of temperature increases to control the

precision of the method. Bitumen is flammable

liquid at high temperature and therefore,

there is a risk of catching fire if care is not

exercised during construction. Its primary

use is to define the critical

temperature at and above which suitable

precautions should be taken to eliminate

fire hazards during its application.

4. Apparatus

4.1. Cleave open cup

4.2. Heater

4.3. Thermometer

5. Procedure

5.1. Heat the bitumen until it converts into liquid form with temp not exceeding 100C.

5.2. Fill the cup and place it at a room temperature for one hour.

5.3. Heat the bitumen at the rate of 5 1C/minute.

5.4. When the temperature reaches near flash point or when sparking is started the test flame

is applied to specimen.

13

5.5. Meanwhile as the bitumen takes fire momentarily that is the flash point, record the

temperature and when it takes fire for at least 5 seconds completely that is the fire point

temperature.

5.6. The flash point is taken as the temperature read on the thermometer at the time of flame

application when flash appears first at any point on the surface of material .The heating

is continued until the volatile ignite and the bitumen continues to burns for 5seconds.

The mean value should not differ from the individual values by more than 30C for flash

point and by 10C for fire point.

6. Observations and Calculations

6.1. Bitumen grade …………………….

6.2. Type of equipment ....…….………………

6.3. Rate of heating …………………………

Test property Test Number Mean

1 2 3

1. Flash point

2. Fire point

3. Variation from

Mean Value

7. NHA Specifications

8. P

re

c

a

ut

ions

8.1. All parts of the cup should be clean and dried.

8.2. The cup should be filled up to filling mark.

8.3. For preparation of sample liquid asphalt should be heated at lowest temperature

8.4. The mean value should not differ from the individual values by more than 30C for flash

point and by 10C for fire point.

9. Practical Applications

1.

2.

Serial Bitumen Grade Flash Point Fire Point

1 40/50 2320C 2420C

2 60/70 2320C 2420C

3 80/100 2320C 2420C

4 120/150 2180C 228C

14

3.

15

EXPERIMENT NO 5 STANDARD TEST FOR VISCOSITY OF ASPHALTS

(BS 4693: 1971 & ASTM D 88 – 94 Reapproved 1999)

1. Scope

This method determines the viscosity of cutback bitumen and road oil in arbitrary units using

the Standard Tar Viscometer. Two forms of the apparatus are described, differing in the size of

the orifice, the diameter of the larger orifice being 10 mm and the smaller 4 mm. The 10 mm

cup is used at 25oC for materials whose viscosity at that temperature and in that cup exceeds 15

sec, and at 40oC for materials whose viscosity at 25oC exceeds 500 sec. The 4 mm cup is used

at a temperature of 25oC for materials whose viscosity is less than 15 sec in the 10 mm cup at

25oC.

2. Standard

BS 4693: 1971 & ASTM D 88 – 94 Reapproved 1999

3. Significance

Viscosity is the inverse of fluidity. The degree of fluidity at the application temperature greatly

influences the ability of bituminous material to spread, penetrate into voids and also coats the

aggregate and hence affects the strength and characteristics of resulting paving mixes. At high

fluidity or low viscosity, bitumen binder simply lubricates the aggregate particles instead of

providing a uniform film thickness for binding action. Low fluidity or high viscosity does not

enable the bitumen to coat the entire surface of aggregate in the mix easily and also resists the

compactive effort and resulting mix is heterogeneous in character. This unique temperature/

viscosity relationship is important when determining the performance parameters such as the

adhesion, rheology, durability and application temperatures of bitumen.

4. Apparatus

4.1. Tar Viscometer with cups having orifice of 4 mm and 10 mm diameters.

4.2. Water Bath.

4.3. Thermometer

4.4. Thermometer Support.

4.5. Receiver Flask (a 100 ml cylinder with graduations at 20 ml, 25 ml, and 75 ml

capacities).

4.6. Time Recorder (a stop watch).

16

Standard Tar Viscometer

Cups with 10 mm and 4 mm diameter Orifices

Stopper Being Inserted to Close the In-built Water Bath

Opening

17

Electro-Thermal Control of Water Bath Graduated Flask Placed to Pour Tar

5. Procedure

5.1. Obtain a fresh sample free of water (< 0.2%).

5.2. Heat the sample in an oven at a temperature which is at least 50oF (28oC) below the

flash point and in any case not over 325oF (163oC) until it has become sufficiently

fluid to pour, occasionally stirring the sample to aid heat transfer and to assure

uniformity. Then allow the sample, still in the closed container, to cool to a

temperature slightly above that at which the test is to be made.

5.3. Clean the viscometer cup with a suitable solvent and then thoroughly dry it to

remove all trace of solvent.

5.4. Insert a stopper in the bottom of the viscometer cup and fill the cup with the prepared

sample.

5.5. Pass a thermometer through the central hole so that its bulb is approximately at the

geometric center of the sample.

5.6. Place the cup in the viscometer water-bath.

5.7. Set up the viscometer in a level position, fill the bath with water and adjust its

temperature and maintain it to within + 0.1oC of the test temperature for a period of

1.5 hour. Throughout the test maintain the bath temperature at this value, stirring

frequently.

5.8. Remove the thermometer and stopper.

5.9. Pour light mineral oil into the receiver up to the 20 ml graduation mark and place the

receiver directly under the orifice of the cup.

5.10. Lift the stopper and suspend it on the valve support.

5.11. Start the time recording device when liquid in the receiver reaches 25 ml graduation

mark and stop it when the liquid reaches the 75 ml graduation mark.

6. Observations and Calculations

Report the time obtained as per procedure mentioned above to the nearest whole second as the

viscosity, stating which cup was used and the temperature of the test.

Viscosity (Seconds) Test Temp oF (oC) Cup Orifice Size (mm)

________________ ________________ ___________________

18

________________ ________________ ___________________

________________ ________________ ___________________

________________ ________________ ___________________

7. Precision

Results of duplicate tests should not differ by more than the following amounts:-

Viscosity (seconds) Repeatability

(one operator and apparatus)

Reproducibility

(different operators and apparatus)

Below 20 2 Sec 2 sec

20 – 40 2 Sec 10 % of the mean

Above 40 5 % of the mean 10 % of the mean

8. Precautions

8.1. Set up the viscometer and bath in an area where they will not be exposed to drafts or

rapid changes in air temperature, and dust or vapors that might contaminate a

sample.

8.2. Do not make viscosity measurements at temperatures below the dew point of the

room's atmosphere.

8.3. Provide adequate stirring and thermal control for the bath so that the temperature of

a test sample in the viscometer will not vary more than ±0.03°C (± 0.05°F) after

reaching the selected test temperature.

8.4. Never preheat any sample within 28°C (50°F) of its flash point, because volatility

losses might alter its composition.

8.5. Do not touch the overflow rim with the withdrawal tube; the effective liquid head of

the sample would be reduced.

9. Practical Applications

1.

2.

3.

19

20

EXPERIMENT NO 6

EXTRACTION TEST OF BITUMEN MIX

(ASTM Designation, D2172 Method ‘A’ & AASHTO T164-90)

1. Scope

Paving mixture is tested to determine conformity with bitumen content requirement. The

process consists of dissolving the bituminous binder in the mixture of known weight in a

suitable solvent and separating the aggregate by the percentage of bituminous material is

computed.

2. Standard

ASTM Designation, D2172 Method ‘A’ & AASHTO T164-90

3. Significance

To find out the Bitumen %age in bitumen mix.

4. Apparatus

4.1. Centrifuge Extraction machine.

4.2. Filter paper.

4.3. Oven capable of being maintained at 110C

4.4. Balance 5kg capacity accuracy 0.1gm

4.5. Spatula or trowel and large flat pan/tray

21

5. Procedure

5.1. Place the bitumen mix in flat pan or tray and heat it in an oven at a temperature of

110C until it’s sufficiently soft so that the particles of the sample can be separated with

a spatula or trowel.

5.2. Weight a representative sample of about 650 ---2500 gm

5.3. Place the sample into the bowl of the extraction machine distributing it uniformly

around the periphery of the bowl.

5.4. Cover the sample with solvent (C.T.C or Petrol) allowing sufficient time for the solvent

to disintegrate the sample.

5.5. Place the bowl containing the sample and solvent in the extraction machine, fit the filter

ring (Filter paper) around the edge of the bowl and clamp the bowl tightly in place.

5.6. Start the machine; first revolve slowly then increase the speed sufficiently to allow the

dissolved bitumen to flow out of the spout.

5.7. Stop the machine, add some fresh solvent and repeat this procedure until a clear extract

emerges.

5.8. Dry the contents of the bowel in the oven at a temperature of 110C till a constant

weight is obtained and calculate the percentage of bitumen in the sample as follows:-

6. Calculation and Observation:-

Wt of sample before test =…………………………….

Wt of sample after test =……………………………

Increase in wt of filter paper (After test) =…………………………….

Wt of the total mineral aggregate =……………………………

Wt of bitumen content =……………………………

Percentage of bitumen content =……………………………

Gradation of Mineral Aggregate after Test

Sieve

size

Wt.

Retained Cum wt. Passing %

Specification

%passing

3 / 4”

1 / 2”

3/8

# 4

# 10

#20

22

# 40

# 60

# 200

Pan

Total

7. Precautions

7.1. Heat the sample with care.

7.2. Avoid heat and open flames.

7.3. Keep container tightly closed.

7.4. Gloves should be worn

7.5. Good ventilation while the test is being performed.

7.6. All equipment should be cleaned frequently to prevent testing errors.

8. Practical Applications

1.

2.

3.

23

EXPERIMENT NO 7 PREPARATION OF JOB MIX

(AASHTO: T166-88, T245-90, T269-90, T228-90, T 84-88 & 85-88 )

1. Scope.

The design of asphalt mix, as with other engineering materials designs, is largely a matter of

selecting and proportioning materials to obtain the desired proportion is the finished

construction. The overall objectives for the design of asphalt paving mixes is to determine an

economical blend and gradation of aggregate and asphalt that yields a good and durable

pavement structure.

2. Standard

AASHTO: T166-88, T245-90, T269-90, T228-90, T 84-88 & 85-88

3. Significance

Design of asphalt paving mixes

4. Apparatus.

4.1. Specimen mold assembly 4.2. Specimen Extractor 4.3. Balance (1.0gm-----3kg) 4.4. Heater

4.5. Oven (0------200 C)

4.6. Mixing apparatus

4.7. Thermometer (0----200 C)

4.8. Rubber and canvas Gloves 4.9. Hot plate

5. Procedure.

5.1. Take about 1150 gm. of aggregate material according to the specification.

5.2. Add bitumen content at different %ages (about 3 to 6%) and heat at a temperature of 150

C.

5.3. Mix the aggregate and bitumen thoroughly so that each particle is well coated. 5.4. Check the temperature time by time so, that it does not exceed the standard temperature

(163±5C).

5.5. Place the mixed material in the assembly and heat the mold before placing the mix.

24

5.6. Used the technique during placing of mix and compact the material according to the type

of traffic i.e. low load, medium, and heavy load (35, 50, 75 blows each side) respectively

at a temperature 143± 5 C.

5.7. After compaction bring the mold in room temperature and extract the specimens

5.8. Determine the density and voids.

6. Observation & Calculation

S No. Description %age

used

Bulk

Sp. Gr.

Apparen

t Sp. Gr.

Effectiv

e Sp.

Gr.

1. Coarse Agg Ret on # 4 sieve 50 2.74 2.81 2.78

2. Fine Agg passing # 4 &Ret on # 200

sieve 44.5 2.71 2.78 2.75

3 Filler passing # 200sieve 5.5 2.62 2.62 2.62

4. Bitumen 1.03 1.03 1.03

Gradation

Sieve

Size

Specification limits

(Passing %)

Mid limits

(Passing %)

% Retained

Retained Wt.

(gm.) Ret. Wt =

Ret%x1150/100

3/4” 100 100 -- --

1 / 2” 75 – 90 82.5 100-82.5 = 17.5 201

3 / 8” 60 – 80 70 82.5-70 = 12.5 144

#4 40 – 60 50 70-50 = 20 230

$8 20 – 40 30 50-30 = 20 230

#50 5 – 15 10 30-10 = 20 230

#200 3 – 8 5.5 10- 5.5 = 4.5 52

-- 200 -- -- 1-94.5 = 5.5 63

7. Precautions

7-1 Mixing should be uniform 7-2 Heat the sample carefully 7-3 Gloves should be worn

8. Practical Applications

1.

2.

3.

25

26

EXPERIMENT NO 8

MARSHALL FLOW AND STABILITY TEST FOR JOB MIX

(AASHTO: T166-88, T245-90, T269-90, T228-90, T 84-88 & 85-88 )

1. Scope.

This test covers the measurement of stability and flow of cylindrical specimen of bituminous

pavement mixture loaded on lateral surface by means of marshal machine.

2. Standard

AASHTO: T166-88, T245-90, T269-90, T228-90, T 84-88 & 85-88

3. Significance

The Marshall Stability and flow test

provides the performance

prediction measure for the Marshall

Mix design method. This test attempts

to get the optimum binder content for the

aggregate mix type and traffic

intensity.

4. Apparatus

2.1 Marshall machine

2.2 Water bath

2.3 Oven (0------200 C)

2.4 Thermometer (0----200 C)

2.5 Rubber and canvas Gloves

5. Procedure:

5.1. Place the specimen in water bath for 30 minutes at temperature of 60C

5.2. After 30 minutes immersion the specimens are tested for stability and flow.

5.3. The stability values obtained or corrected when the height of the specimen tested is other

than 2-1/2 in using correction factors.

6. Observation & Calculation

Bulk Combined Sp. Gr. (Gsb) = ____________________100___________________

% C.A/Bulk S G+%F.A/Bulk S G+% Fine/Bulk S G

27

Effective Sp. Gr. (Gse) =____________________100______________________

%C.A/Effect S.G+%F.A/Effect S.G+% Filler/Effect S.G

Bulk Sp. Gr. of compacted mix (Gmb) = A/ (B-C)

Where,

A= wt of specimen in air gm.

B= wt of specimen S.S.D gm.

C= wt of specimen in water gm.

Max Theoretical Sp. Gr. (Gmm) = 100 / (%Agg/Gse+% A.C/S G of A.C)

Percent Air Voids (P.A.V) = Gmm-Gmb/Gmm x 100

Voids in mineral aggregate (V.M.A) = 100-Gmmx%Aggregate/Gsb

Voids filled with bitumen (V.F.B) = V.M.A-P.A.V/V.M.A x 100

7. Specification For Wearing Coarse

7.1. Stability 1000kg Min

7.2. Flow 2-----3.5mm

7.3. P.A.V 3-----5 %

7.4. V.M.A 14min

7.5. V.F.B 65----75 %

7.6. Loss of Stability 20% of max

Table No.2

Specimen

No.

Bitumen

content

Percent

Stability value (Kg) Flow value 0.25/0.1 mm

units Measured Corrected

1.

2.

3.

Average

1.

2.

3.

Average

28

1.

2.

3.

Average

29

8. Stability Correction Ratio

Volume of

specimen

Cm3

Approximate

thickness of

specimen mm

Correctio

n ratio

Volume of

specimen

Cm3

Approximate

thickness of

specimen mm

Correctio

n ratio

200 to 213 25.4 5.56 393 to 405 49.2 1.56

214 to 215 27.0 5.0 406 to 420 50.8 1.47

226 to 237 28.6 4.55 421 to 431 52.4 1.39

238 to 250 30.2 4.17 432 to 443 54.0 1.32

251 to 264 31.8 385 444 to 456 55.6 1.25

265 to 276 33.3 3.5 457 to 470 57.2 1.19

277 to 289 34.9 3.33 471 to 482 58.7 1.14

290 to 301 36.5 3.03 483 to 495 60.3 1.09

302 to 316 38.1 2.76 496 to 508 61.9 1.04

317 to 328 39.7 2.5 509 to 522 63.5 1.0

329 to 340 41.3 2.27 523 to 535 64.0 0.96

341 to 353 42.9 2.08 536 to 546 65.1 0.93

354 to 367 44.4 1.92 547 to 559 66.7 0.89

368 to 379 46.0 1.79 560 to 573 68.3 0.86

380 to 392 47.6 1.67 574 to 585 71.4 0.83

30

9. Marshal Test Graphs

Asphalt Content %

Asphalt Content % Asphalt Content %

Asphalt Content % Asphalt Content %

PA

V (

%)

Unit

W e

ight

(gm

/cc)

F

low

(m

m)

Sta

bil

ity (

Kg)

VF

B (

%)

31

Asphalt Content (%)

Unit

Wei

ght

(gm

/cc)

32

Asphalt Content (%)

PA

V (

%)

33

Asphalt Content (%)

Flo

w (

mm

)

34

Asphalt Content (%)

Sta

bil

ity (

kg)

35

Asphalt Content (%)

VF

B (

%)

36

Note:-Graphs should be plotted between

%A.C vs. Stability

%A.C vs. Flow

%A.C vs. Unit weight

%A.C vs. P.A.V (A tolerance of one percent of air voids may be permitted)

%A.C vs. V.M.A

%A.C vs. V.F.B

10. Results

Asphalt content at maximum unit weight (a) =

Asphalt content at maximum Stability (b) =

Asphalt content at 4% (1) PAV (c) =

Optimum Asphalt content (a + b+ c / 3) =

Table 1

Specimen

No.

%age of

Aggregate

Bitumen

content %

Weights (gm.)

In air

In water

SSD Wt.

Vol.of Speci

1

2

3

4

5

6=5-4

1.

2.

3.

Avg

1.

2.

3.

Avg

1.

2.

3.

Avg

1.

2.

3.

3.

Avg

37

11. Precautions

11-1 Mixing should be uniform 11-2 Heat the sample carefully 11-3 Gloves should be worn 11-4 Give Blows gently to avoid any injury.

12. Practical Applications

1.

2.

3.

Bulk

density

(Gmb)

Bit.Gs

Gse of

Agg

Max Theo

Gs (Gmm)

PAV

VMA

VFB

7=3/6

8

9

10=100/

(1/9+2/8)

11=10-

7/10x100

12=100--7x1/Gsb

13=12--

11/12x100

38

39

EXPERIMENT NO 9 AGGREGATE IMPACT VALUE TEST

ASTM D5874 - 02

1. Scope:

Aggregate impact value gives the relative strength of aggregates against impact loading.

2. Standard

ASTM D5874 - 02

3. Significance

Toughness is the property of material to

resist impact due to traffic loads. The road

stones are subjected to the pounding action or

impact and there is possibility of aggregate

stone breaking into smaller pieces. The road

aggregate should therefore be tough enough to

resist fracture under impact.

4. Apparatus:

4.1. Impact testing machine

4.2. Weighing balance

4.3. Sieve 14mm, 10mm, 2.36mm

4.4. Oven

4.5. Cup of dia 10.2cm and depth 5cm

4.6. Temping rod of dia 1.0cm and 23cm long

5. Procedure:

5.1. About 350g of aggregate passing 14mm sieve and retained on 10mm sieve are

selected.

5.2. Place the aggregate in the impact testing machine cup and tamp each layer with 25

blows using temping road.

5.3. The aggregate is subjected to 15 blows by a standard rammer of weight 14 kg falling

from 38cm.

5.4. After the application of specified number of blows the aggregate is taken out from the

cup and sieved through 2.36mm and %age of passing material is calculated

5.5. Results are calculated as percentage fines passing 2.36mm sieve.

40

6. Observations & Calculations:

Wt of aggregates passing 14mm and retained on 10mm sieve A =__________

Wt of fines passing 2.36mm sieve B = ________________

Impact value of aggregate = B/A*100 (%) = ___________________

7. Specification:

7.1. Exceptionally strong = Less than 10%

7.2. Strong = 10% to 20%

7.3. Satisfactory for road construction = 20% 30%

8. Precautions

8.1. Use gloves while removing containers from oven after switching off the oven.

8.2. Wear safety shoes & goggles at the time of testing.

8.3. Before testing, machine should be properly checked.

8.4. Special care should be taken that no outer air enters when using the balance.

8.5. After performing the test, clean the sieve with a smooth brush.

8.6. Keep all the exposed metal parts greased.

8.7. Keep the guide rods firmly fixed to the base & top plate.

8.8. Equipment should be cleaned thoroughly before testing & after testing.

9. Practical Applications

1.

2.

3.

41

EXPERIMENT NO 10 AGGREGATE CRUSHING VALUE TEST

BS: 812 & IS: 383-2386

1. Scope

This test is to determine the indirect measure of crushing value of aggregate. Low aggregate

crushing value indicates strong aggregate as the crushed fraction is low.

2. Standard

BS: 812 & IS: 383-2386

3. Significance

Aggregate used in road construction should be strong enough to resist crushing under

traffic wheel load. If the aggregate is weak, the stability of the pavement structure is likely

to be adversely affected.

4. Apparatus:

4.1. Steel cylinder with open ends.

(15.2cm dia and 15cm height)

4.2. Cylindrical measure inner dia

11.5cm, height 18cm

4.3. Tamping rod with rounded ends.

(1.6cm Dai and 60cm length)

4.4. Compression machine. (50 ton

capacity)

4.5. Weighing Balance

5. Procedure:

5.1. Wash the sample thoroughly and oven dry.

5.2. The aggregate passing from 14mm sieve and retained on 10mm (9.5 mm) sieve are

selected for test.

5.3. Place the aggregate in three equal layers in the cylindrical measure and each layer

may be tamped 25 blows and then weigh.

5.4. Place the cylinder of the test apparatus in position on the base plate, and place the

aggregate in three layers in the cylinder, each layer may be tamped with 25blows.

5.5. Insert the plunger in the cylinder and subject it in the compression machine.

5.6. Apply the load at a rate of 4 Ton/ minute up to 40 Ton.

42

5.7. Sieve the materials from 2.36 mm sieve and determine the %age of fines passing.

5.8. Results are reported as %age fine passing 2.36mm sieve after crushing.

6. Calculation:

6.1. Weight of dry sample before test, W1 = _____________

6.2. Weight of fines passing from 2.36mm sieve after test, W2 = __________

6.3. Aggregate Crushing Value = W2/W x100 (%) = _________________

7. Specification:

7.1. Base coarse < 30%

7.2. Wearing coarse < 15%

8. Precautions

8.1. Use hand gloves while removing containers from oven after switching off the oven.

8.2. To wear safety shoes & goggles at the time of testing.

8.3. Before testing, machine should be properly checked.

8.4. Special care should be taken that no outer air enters when using the balance.

8.5. After test clean the sieve by a smooth brush.

8.6. Keep all the exposed metal parts greased.

8.7. Keep the guide rods firmly fixed to the base & top plate.

8.8. Equipment should be cleaned thoroughly before testing & after testing.

9. Practical Applications

1.

2.

3.

43

EXPERIMENT NO 11

LOS ANGELES ABRASION TEST

ASTM C 535 & AASHTO T-96

1. Scope

This test is to determine the hardness of aggregate. Aggregates with distinctly different

origins should be expected to perform differently in this test machine.

2. Standard

ASTM C 535 & AASHTO T-96

3. Significance

Aggregate used in road

construction should be strong enough

to resist the wear due the heavy traffic

load. If the aggregate have high

abrasion value the stability of road

pavement is likely to be

adversely affected.

4. Apparatus

4.1. Loss Angeles abrasion machine

4.2. Balance

4.3. Oven (maintaining a uniform temperature of 230 ±9°F)

4.4. Set of sieves and sieve No.12, Steel balls/Charge (390/445gm) approx. 127/32 inches

in dia.

4.5. Shelf/trays

5. Sample Preparation:

5.1. The disturbed representative test sample shall consist of clean washed aggregate that

has been oven-dried to constant mass at a temperature of 230 ±9° F. Separate the

sample into individual size fractions by sieving, and recombine to the grading of Table

44

1 or Table 2 that most nearly corresponds to the range of sizes in the aggregate as

furnished for testing. The sample mass shall be recorded to the nearest 1 g.

6. Procedure:

6.1. The test sample should be thoroughly washed and oven dried and is taken according to

gradation in tables.

6.2. The test sample and abrasive charges shall be placed in the Los Angeles abrasion

machine and the machine is rotated at a speed of 30 to 33 Rpm for 500 revolutions for

test method AASHTO T 96; 1000 revolutions for test method ASTM C 535.

6.3. After the prescribed number of revolutions the material shall be discharged carefully

from the machine and shall be sieved on 1.7mm (#12) sieve.

6.4. Wash the material coarser than the No. 12 sieve, dry to constant mass at 230 ±9 0F,

and record mass to the nearest 1 g.

7. TABLE 1 AASHTO T-96 Sample Grading for Small size Aggregates.

8. TABLE 2 ASTM C535 Sample Grading for large size Aggregates.

45

9. Observations and Calculations:

Weight of dry sample before test, W1 = ______________

Weight of sample passing from 12 # sieve, W2 = _______________

Or W2 =original sample mass –final sample mass

Abrasion value of Aggregate = W2x100/W1 (%) = ____________________

10. Specification:

10.1. Granular Sub Base: The coarse aggregate materials retained on sieve No. 4 shall

have a percentage of wear by Los Angeles abrasion test (AASHTO T-96) of not

more than 50 %.

10.2. Aggregate Base Course: The coarse aggregate material retained on sieve No.4 shall

have a percentage of wear by Los Angeles abrasion test (AASHTO T-96) of not

more than 40%.

11. Precautions

11.1. The Los Angeles abrasion testing machine shall be periodically checked for wear

and maintained to comply with the original specifications.

11.2. Laboratory must be in closed area especially at the measuring area to avoid the

wind resistance which can affect the weight data or closed box of measuring

machine.

11.3. After doing the experiment, all the apparatus must been cleaned and kept at a

clean place to avoid any dust entering the apparatus.

11.4. Machine must be maintained regularly. All the damages must be repaired before

being used by the student. It will also help in avoiding accidents in laboratory.

46

11.5. The accurate amount of steel balls will make the collected data more efficient. The

sample will break into what we are supposed to get.

12. Practical Applications

1.

2.

3.

47

EXPERIMENT NO 12

SHAPE TEST FOR AGGREGATES

ASTM D 4791-99

1. Scope:

This test method covers the determination of the percentages of flaky and elongated

particles, and in case of gravel determine by its Angularity No. The flakiness index of

aggregate is the percentage of the mass of the aggregates whose least dimension is less than

0.6 times the mean dimension. The flakiness test is applicable to aggregates of size larger

than 6.3.Elongated particles greatest dimension is greater than 1.8 times their mean size

(dimension) and the angularity number of an aggregate is the amount (to the nearest whole

number) by which the % age voids in it after compacting in a prescribed manner, exceeds

33.

2. Standard

ASTM D 4791-99

3. Significance

Rounded aggregates are

preferred in concrete

pavements for their higher

workability and

crushing. Angular shape

aggregates are used in flexible

pavement for their better

interlocking and

friction.

4. Apparatus:

4.1. Flaky sieves

4.2. Elongation gauges

4.3. Set of sieves

4.4. Balance

4.5. Cylinder 3 Liter capacity

4.6. Tamping rod, Oven and Scoop

5. Procedure:

48

5.1 Flakiness & Elongation of Aggregates

5.1.1 If determination by mass is required, oven dry the sample to constant mass at a

temperature (105 ˚C).

5.1.2 If determination is by particle count, drying is not necessary.

5.1.3 The given sample is sieved through square opening sieves; the retained particles

are weighed and denoted as W1, W2, and W3---Wn.

5.1.4 The sample is placed in separate plates, passing and retained sieve size for each

fraction is written on the plate.

5.1.5 The sample is passed by its least dimension through the corresponding opening of

the flaky sieves. Weigh separately and record as F1, F2, and F3--------------Fn.

5.1.6 Collect all the material passed and retained, now pass this material through the

Elongation gauge. The retained material on elongation gauge are weighted and

recorded as E1, E2-------En.

5.2 Angularity Number

5.2.1 Take at least 10 Kg of aggregate sample and sieve with specified sieves,

5.2.2 The sample should be placed in cylinder in three equal layers

5.2.3 Each layer should be tamped 100 times by means of a tamping rod.

5.2.4 Weigh the cylinder with aggregate and determine the weight of aggregate (W).

5.2.5 At least three readings are taken.

5.2.6 Find the volume of cylinder with water at 27 ˚C.

6 Observations and Calculations:

Flakiness Index = ∑F x 100 / ∑W = %

Elongation Index = ∑E x 100 / ∑W = %

49

Angularity No = 67 – W x100 / (Ww x Gs) =

Where,

W = wt of aggregate in cylinder

Ww = wt of water in cylinder

Gs = Specific gravity of aggregate

7. Specification:

7.1. Flakiness Index < 15 %

7.2. Elongation Index < 15 %

7.3. Angularity Number = 0 to 11

8. Precautions

8.1. Use hand gloves while removing containers from oven after switching off the oven.

8.2. Use safety shoes, mask & aprons at the time of test.

8.3. Thoroughly clean & dry the container before testing.

8.4. Special care should be taken that no outer air enters when using the balance.

8.5. All parts of the equipment should always be kept clean.

8.6. After the completion of test sieves should be cleaned by smooth brush.

9. Practical Applications

1.

2.

3.

50

EXPERIMENT NO 13

WATER ABSORPTION TEST OF AGGREGATES

ASTM C 127-12

1. Scope

This test helps to determine the water absorption of coarse aggregates.

2. Standard

ASTM C 127-12

3. Significance

Stones having higher water absorption values are porous

and hence weak. Higher value of water absorption

implies more Bitumen absorption. Freeze and thawing

effect would be larger for more water absorption.

4. Apparatus:

4.1. Wire basket – perforated, electroplated or plastic

coated with wire hangers for suspending it from the

balance,

4.2. Water-tight container for suspending the basket,

4.3. Dry soft absorbent cloth – 75cm x 45cm (2 nos.),

4.4. Shallow tray of minimum 650 sq.cm area,

4.5. Air-tight container of a capacity similar to the basket and Oven.

5. Procedure:

5.1. The sample should be thoroughly washed to remove finer particles and dust, drained and then

placed in the wire basket and immersed in distilled water at a temperature between 22 and 32 C.

5.2. After immersion, the entrapped air should be removed by lifting the basket and allowing it to

drop 25 times in 25 seconds. The basket and sample should remain immersed for a period of 24

+ ½ hours afterwards.

5.3. The basket and aggregates should then be removed from the water, allowed to drain for a few

minutes, after which the aggregates should be gently emptied from the basket on to one of the

dry clothes and gently surface-dried with the cloth, transferring it to another dry cloth when the

first would remove no further moisture. The aggregates should be spread on the other cloth and

51

exposed to the atmosphere away from direct sunlight till it appears to be completely surface-

dry. The aggregates should be weighed (Weight ‘A’).

5.4. The aggregates should then be placed in an oven at a temperature of 100 to 110˚C for 24hrs. It

should then be removed from the oven, cooled and weighed (Weight ‘B’).

5.5. Two such tests should be done and the individual and mean results should be reported.

6. Observations and Calculations:

Observation-1

Weight of saturated surface dry sample, A = _______________

Weight of oven dry sample, B = _______________

Water absorption = [(A - B)/B] x 100% = ______________________

Observation-2

Weight of saturated surface dry sample, A = _______________

Weight of oven dry sample, B = _______________

Water absorption = [(A - B)/B] x 100% = ______________________

Mean Water absorption = ____________________

7. Precautions

7-1Thoroughly clean & dry the container before testing.

7-2 Special care should be taken that no outer air enters when using the balance.

7-3 To wear safety shoes & apron at the time of test.

8. Practical Applications

1.

2.

3.

52

EXPERIMENT NO 14

SPECIFIC GRAVITY OF COARSE AGGREGATES

ASTM C 127-12

1. Scope

This test is done to determine the specific gravity of fine-grained soil by density bottle method.

Specific gravity is the ratio of the weight in air of a given volume of a material at a standard

temperature to the weight in air of an equal volume of distilled water at the same stated

temperature.

2. Standard

ASTM C 127-12

3. Significance

In the asphalt mix design industry, the bulk specific

gravity and absorption of the aggregates, both fine and coarse, is

crucial for quality asphalt design. Bulk specific gravity is

used to determine the amount of asphalt binder absorbed by

the aggregates and the percentage of voids in the mineral

aggregates which are both important in design and quality

control.

4. Apparatus:

4.1. Two density bottles of approximately 50ml

capacity along with stoppers,

4.2. Constant temperature water bath (27.0 + 0.2 C),

4.3. Vacuum desiccator,

4.4. Oven, capable of maintaining a temperature of 105 to 110 C

4.5. Weighing balance, with an accuracy of 0.001g,

4.6. Spatula

5. Preparation of Sample

The soil sample (50g) should if necessary be ground to pass through a 2mm IS Sieve. A 5 to 10g

sub-sample should be obtained by riffling and oven-dried at a temperature of 105 to 110 C.

6. Procedure:

53

6.1. The density bottle along with the stopper, should be dried at a temperature of 105 to

110 C, cooled in the desiccator and weighed to the nearest 0.001g (W).

6.2. The sub-sample, which had been oven-dried, should be transferred to the density bottle

directly from the desiccator in which it was cooled. The bottles and contents together

with the stopper should be weighed to the nearest 0.001g (W).

6.3. Cover the soil with air-free distilled water from the glass wash bottle and leave for a

period of 2 to 3hrs for soaking. Add water to fill the bottle to about half.

6.4. Entrapped air can be removed by heating the density bottle on a water bath or a sand

bath.

6.5. Keep the bottle without the stopper in a vacuum desiccator for about 1 to 2hrs, until

there is no further loss of air.

6.6. Gently stir the soil in the density bottle with a clean glass rod, carefully wash off the

adhering particles from the rod with some drops of distilled water and see that no more

soil particles are lost.

6.7. Repeat the process till no more air bubbles are observed in the soil-water mixture.

6.8. Observe the constant temperature in the bottle and record.

6.9. Insert the stopper in the density bottle, wipe and weigh (W).

6.10. Now empty the bottle, clean thoroughly and fill the density bottle with distilled water

at the same temperature. Insert the stopper in the bottle, wipe dry from the outside and

weigh (W).

6.11. Take at least two such observations for the same soil.

7. Observations and Calculations

54

55

8. Precautions:

56

8.1. When tare weight is used to compensate for the weight of the suspended basket, be

certain the correct tare weight is used.

8.2. Thoroughly clean & dry the container before testing.

8.3. Special care should be taken that no outer air enters when using the balance.

8.4. Use apron & safety shoes at the time of testing.

8.5. All parts of the equipment should always be kept clean.

9. Practical Applications

1.

2.

3.

57

EXPERIMENT NO 15

CALIFORNIA BEARING RATIO (CBR) TEST

AASHTO T 192-81

1. Scope

This laboratory method covers the determination of C.B.R. of undisturbed and remolded

/compacted soil specimens, both in soaked as well as unsoaked state. The California bearing ratio

test is a penetration test meant for the evaluation of subgrade strength of roads and pavements.

The results obtained by these tests are used with the empirical curves to determine the thickness of

pavement and its component layers. This is the most widely used method for the design of flexible

pavement. It is the ratio of force per unit area required to penetrate a soil mass with standard

circular piston at the rate of 1.25 mm/min. to that required for the corresponding penetration of a

standard material. The test may be performed on undisturbed specimens and on remolded

specimens who may be compacted either statically or dynamically.

2. Standard

AASHTO T 192-81

3. Significance

The California bearing ratio (CBR) is a penetration

test for evaluation of the mechanical

strength of road subgrades and base courses. It

gives corporative idea of strength of various

locally available materials.

4. Apparatus:

9.1. Cylindrical mold with inside dia 150

mm and height 175 mm, provided with

a detachable extension collar 50 mm

height and a detachable perforated base plate 10 mm thick

9.2. Spacer disc 148 mm in dia and 47.7 mm in height along with handle, Metal rammers

9.3. Weight 2.6 kg with a drop of 310 mm (or) weight 4.89 kg a drop 450 mm

9.4. Weights. One annular metal weight and several slotted weights weighing 2.5 kg each,

147 mm in dia, with a central hole 53 mm in diameter

58

9.5. Loading machine, With a capacity of at least 5000 kg and equipped with a movable

head or base that travels at an uniform rate of 1.25 mm/min. Complete with load

indicating device

9.6. Metal penetration piston 50 mm dia and minimum of 100 mm in length

9.7. Two dial gauges reading to 0.01 mm

9.8. Sieves. 4.75 mm and 20 mm I.S. Sieves

9.9. Miscellaneous apparatus, such as a mixing bowl, straight edge, scales soaking tank or

pan, drying oven, filter paper and containers.

5. Preparation of Sample

5.1. Undisturbed specimen:

Attach the cutting edge to the mold and push it gently into the ground. Remove the soil from the

outside of the mold which is pushed in. When the mold is full of soil, remove it from weighing the

soil with the mold or by any field method near the spot.

5.2. Remolded specimen

Prepare the remolded specimen at Proctor’s maximum dry density or any other density at which

C.B.R> is required. Maintain the specimen at optimum moisture content or the field moisture as

required. The material used should pass 20 mm I.S. sieve but it should be retained on 4.75 mm I.S.

sieve. Prepare the specimen either by dynamic compaction or by static compaction.

6. Procedure:

6.1. Dynamic Compaction:

6.1.1. Take about 4.5 to 5.5 kg of soil and mix thoroughly with the required water.

6.1.2. Fix the extension collar and the base plate to the mold. Insert the spacer disc over the base

(See Fig.38). Place the filter paper on the top of the spacer disc.

6.1.3. Compact the mixed soil in the mold using either light compaction or heavy compaction.

For light compaction, compact the soil in 3 equal layers, each layer being given 55 blows

by the 2.6 kg rammer. For heavy compaction compact the soil in 5 layers, 56 blows to each

layer by the 4.89 kg rammer.

6.1.4. Remove the collar and trim off soil.

6.1.5. Turn the mold upside down and remove the base plate and the displacer disc.

6.1.6. Weigh the mold with compacted soil and determine the bulk density and dry density.

6.1.7. Put filter paper on the top of the compacted soil (collar side) and clamp the perforated base

plate on to it.

6.2. Static compaction

6.2.1. Calculate the weight of the wet soil at the required water content to give the desired

density when occupying the standard specimen volume in the mold from the expression.

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W =desired dry density * (1+w) V

Where W = Weight of the wet soil

w = desired water content

V = volume of the specimen in the mold as per the mold available

6.2.2. Take the weight W (calculated as above) of the mix soil and place it in the mold. Place a

filter paper and the displacer disc on the top of soil.

6.2.3. Keep the mold assembly in static loading frame and compact by pressing the displacer disc

till the level of disc reaches the top of the mold.

6.2.4. Keep the load for some time and then release the load. Remove the displacer disc.

6.2.5. The test may be conducted for both soaked as well as un-soaked conditions.

6.2.6. If the sample is to be soaked, in cases of compaction, put a filter paper on the top of the

soil and place the adjustable stem and perforated plate on the top of filter paper.

6.2.7. Put annular weights to produce a surcharge equal to weight of base material and pavement

expected in actual construction. Each 2.5 kg weight is equivalent to 7 cm construction. A

minimum of two weights should be put.

6.2.8. Immerse the mold assembly and weights in a tank of water and soak it for 96 hours.

6.2.9. Remove the mold from tank.

6.2.10. Note the consolidation of the specimen.

6.3. Penetration Test

6.3.1. Place the mold assembly with the surcharge weights on the penetration test machine.

6.3.2. Set the penetration piston at the center of the specimen with the smallest possible load, but

in no case in excess of 4 kg so that full contact of the piston on the sample is established.

6.3.3. Set the stress and strain dial gauge to read zero. Apply the load on the piston so that the

penetration rate is about 1.25 mm/min.

6.3.4. Record the load readings at penetrations of 0.5, 1.0, 1.5, 2.0, 2.5, 3.0, 4.0, 5.0, 7.5, 10 and

12.5 mm. Note the maximum load and corresponding penetration if it occurs for a

penetration less than 12.5 mm.

6.3.5. Detach the mold from the loading equipment. Take about 20 to 50 g of soil from the top 3

cm layer and determine the moisture content.

7. Observations and Calculations

7.1. For Dynamic Compaction

Optimum water content (%) ……………………………..

Weight of mold + compacted specimen g …………………………

Weight of empty mold g ………………………………..

Weight of compacted specimen g……………………………….

Volume of specimen cm3 ……………………………….

60

Bulk density g/cc …………………………………….

Dry density g/cc ……………………………………..

7.2. For Static Compaction

Dry density g/cc ………………………………….

Molding water content % ……………………………………..

Wet weight of the compacted soil, (W)g ……………………………..

Period of soaking 96 hrs (4days).……………………………………

7.3. For penetration Test

Calibration factor of the proving ring 1 Div. = 1.176 kg

Surcharge weight used (kg) 2.0 kg per 6 cm construction

Water content after penetration test % ………………

Least count of penetration dial 1 Div. = 0.01 mm

If the initial portion of the curve is concave upwards, apply correction by drawing a tangent to the

curve at the point of greatest slope and shift the origin. Find and record the correct load reading

corresponding to each penetration.

C.B.R. = PT/Ps x 100

Where

PT = Corrected test load corresponding to the chosen penetration from the load penetration curve.

Ps = Standard load for the same penetration taken from the Table1.

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8. Interpretation & Recording

C.B.R. of specimen at 2.5 mm penetration ………………………………..

C.B.R. of specimen at 5.0 mm penetration ...……………………………….

C.B.R. of specimen ………………………………….

9. Specification:

The C.B.R. values are usually calculated for penetration of 2.5 mm and 5 mm. Generally the

C.B.R. value at 2.5 mm will be greater that at 5 mm and in such a case/the former shall be taken as

C.B.R. for design purpose. If C.B.R. for 5 mm exceeds that for 2.5 mm, the test should be

repeated. If identical results follow, the C.B.R. corresponding to 5 mm penetration should be taken

for design. The following table gives the standard loads adopted for different penetrations for the

standard material with a C.B.R. value of 100%

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10. Precautions

9.10. The maximum size of material particles to be tested is limited to 19 mm. Therefore in

case of gravels initial sieving is essential.

9.11. Blows should be applied uniformly over the entire surface of soil in mold.

9.12. Clean the sieves with the help of a brush, after sieving

9.13. While weighing put the sieve with soil sample on the balance in a concentric position.

9.14. Check the electric connection of the sieve shaker before conducting the test.

11. Practical Applications

1.

2.

3.