highway & traffic engineering lab...

[HIGHWAY & TRAFFIC ENGINEERING LAB MANUAL] 2016

Table of ContentsEXPERIMENT NO 1.................................................................................................................8Layout of Highway & Traffic Engineering Lab.........................................................................8

................................................................................................................................................9List of Laboratory Apparatus.................................................................................................9Core Cutter Apparatus..........................................................................................................10Los Angeles Abrasion Testing Machine..............................................................................10Ductility Testing Machine....................................................................................................11Open Cup Flash & Fire Point Apparatus.............................................................................11Marshal Stability Apparatus.................................................................................................12Penetrometer........................................................................................................................12Pycnometer...........................................................................................................................13Asphalt Centrifuge Extractor...............................................................................................13Flakiness & Elongation Index Apparatus.............................................................................13Screen Shaker.......................................................................................................................14Sieve Shaker.........................................................................................................................15Water Bath............................................................................................................................15Sample splitter......................................................................................................................15

EXPERIMENT NO 2...............................................................................................................16Determination of the flakiness and elongation index for the given aggregate sample............16

Code:....................................................................................................................................16Scope & significance:...........................................................................................................16Related Theory:....................................................................................................................16Shapes of Particles:..............................................................................................................16Preferred use of each shape:.................................................................................................16Apparatuses:.........................................................................................................................17Flaky:....................................................................................................................................17Flakiness index:....................................................................................................................17Elongated particles:..............................................................................................................17Elongation index:.................................................................................................................18Procedure:............................................................................................................................18Precautions:..........................................................................................................................18Performance:........................................................................................................................18Sieve Analysis:.....................................................................................................................19Calculations for flaky particles:...........................................................................................19

DEPARTMENT OF CIVIL ENGINEERING | THE UNIVERSITY OF LAHORE

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Calculations for elongated particles:....................................................................................20Comments:...........................................................................................................................20

EXPERIMENT NO 3...............................................................................................................21Standard test method for resistance to degradation of coarse aggregates by abrasion and impact in Los Angeles abrasion machine.................................................................................21

Code:....................................................................................................................................21Scope & Significance:..........................................................................................................21Notes:...................................................................................................................................21Related theory:.....................................................................................................................22Abrasion:..............................................................................................................................22Pounding action:...................................................................................................................22Los Angeles abrasion value:................................................................................................22Apparatus:............................................................................................................................22Procedure:............................................................................................................................23Notes:...................................................................................................................................23Performance:........................................................................................................................23Grading of test sample (Los Angeles abrasion test):............................................................24Observations & Calculations:...............................................................................................25Comments:...........................................................................................................................25

EXPERIMENT NO 4...............................................................................................................26Penetration Test on Bituminous Materials...............................................................................26

Code:....................................................................................................................................26Penetration:..........................................................................................................................26Grades of Bitumen:..............................................................................................................26Scope:...................................................................................................................................26Specifications:......................................................................................................................26Apparatus:............................................................................................................................26Procedure:............................................................................................................................27Test Specifications:..............................................................................................................27Report:..................................................................................................................................28Calculation and Observation:...............................................................................................28Precautions...........................................................................................................................28Comments:...........................................................................................................................28

EXPERIMENT NO 05.............................................................................................................29Specific Gravity Test on Bituminous Materials.......................................................................29

Code:....................................................................................................................................29Specific Gravity:..................................................................................................................29


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Scope & Significance:..........................................................................................................29Apparatus:............................................................................................................................29Procedure:............................................................................................................................29Preparation of Sample:.........................................................................................................29Calculations:.........................................................................................................................30Observations & Results:.......................................................................................................31Comments:...........................................................................................................................31

EXPERIMENT NO 6...............................................................................................................32Determination of Angularity Number for the Given Aggregate Sample.................................32

Code:....................................................................................................................................32Objectives:............................................................................................................................32Related Theory:....................................................................................................................32Shapes Of Particles:.............................................................................................................32Angularity:...........................................................................................................................32Angularity Number:.............................................................................................................32Significance:.........................................................................................................................33Apparatus:............................................................................................................................33Procedure:............................................................................................................................33Calculation & Results:.........................................................................................................34Method – 1...........................................................................................................................34Method – 2...........................................................................................................................34Notes:...................................................................................................................................34Computations & Results:.....................................................................................................34Comments:...........................................................................................................................35

EXPERIMENT NO 7...............................................................................................................36Specific Gravity (Relative Density) and Water Absorption Test for Aggregates....................36

Code:....................................................................................................................................36Related Theory:....................................................................................................................36Specific Gravity:..................................................................................................................36Water Absorption:................................................................................................................36Coarse Aggregates:..............................................................................................................36Fine Aggregates:..................................................................................................................36Saturated Surface Dry (S.S.D.) Condition:..........................................................................36Oven Dried Specific Gravity:...............................................................................................36Saturated Surface Dry (S.S.D) Specific Gravity:.................................................................36Apparent Specific Gravity:...................................................................................................37


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Types Of Crush Available In Pakistan:................................................................................37Sargodha Crush....................................................................................................................37Margalla Crush.....................................................................................................................37Sakhi Sarwar Crush..............................................................................................................37Significance:.........................................................................................................................37Apparatus:............................................................................................................................38Sample:.................................................................................................................................38Procedure:............................................................................................................................39Observations:........................................................................................................................39Comments:...........................................................................................................................39

EXPERIMENT NO 08............................................................................................................40Softening Point of Bitumen......................................................................................................40

Code:....................................................................................................................................40Softening Point:....................................................................................................................40Scope & Significance:..........................................................................................................40Apparatus:............................................................................................................................40Procedure:............................................................................................................................41A) - For Materials Having Softening Points 80°C Or Below............................................41B) - For Materials Having Softening Points Above 80°C:................................................42Observations & Results:.......................................................................................................42Comments:...........................................................................................................................42

EXPERIMENT NO 09.............................................................................................................43To Perform Ductility Test on Asphalt......................................................................................43

Code:....................................................................................................................................43Related Theory:....................................................................................................................43Ductility:..............................................................................................................................43Importance of Ductility:.......................................................................................................43Scope & Significance:..........................................................................................................43Apparatus:............................................................................................................................44Procedure:............................................................................................................................44Testing:.................................................................................................................................45Observations & Results:.......................................................................................................45Comments:...........................................................................................................................45

EXPERIMENT NO 10.............................................................................................................46Flash And Fire Point Test For Asphalt By Cleveland Open Cup............................................46

Code:....................................................................................................................................46


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Related Theory:....................................................................................................................46Flash Point:...........................................................................................................................46Fire Point:.............................................................................................................................46Scope & Significance:..........................................................................................................46Asphalt Cement (AC):..........................................................................................................47Apparatus:............................................................................................................................47Procedure:............................................................................................................................47Precautions:..........................................................................................................................48Calculations and Report:......................................................................................................48Flash Point of Different Grades of Asphalt:.........................................................................49Viscosity Grades:.................................................................................................................49Observations & Results:.......................................................................................................49Graph:...................................................................................................................................50Results:.................................................................................................................................50Comments:...........................................................................................................................51

EXPERIMENT NO 11.............................................................................................................52Marshall Method of Mix Design..............................................................................................52

Code:....................................................................................................................................52Introduction:.........................................................................................................................52Outline of Method:...............................................................................................................52Selection and Combination of Aggregates:..........................................................................52Mineral Aggregate And Mix Composition:.........................................................................53Sieve Analysis Of Aggregates (Percentage Used For Experiment).....................................53Design Bitumen Content:.....................................................................................................54Preparation Of Test Specimens:...........................................................................................54Apparatus:............................................................................................................................55Test Procedure:.....................................................................................................................55Marshall Stability Value:.....................................................................................................56Flow Value:..........................................................................................................................56Computations:......................................................................................................................56Percentage Air Voids, Va:....................................................................................................56Percentage Of Voids In Mineral Aggregates, Vma:............................................................57Percentage Of Voids Filled With Bitumen, VFB:................................................................57Observations And Calculations:...........................................................................................57Comments:...........................................................................................................................58

EXPERIMENT NO 12.............................................................................................................59


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Design of Flexible Pavement by Group Index Method............................................................59Introduction..........................................................................................................................59Related Theory.....................................................................................................................59Sieve Analysis......................................................................................................................59Atterberg Limits...................................................................................................................60Shrinkage limit.....................................................................................................................60Plastic limit...........................................................................................................................60Liquid limit...........................................................................................................................61Plasticity index.....................................................................................................................61Liquidity index.....................................................................................................................61AASHTO classifications of soils.........................................................................................61AASHTO Classification Chart.............................................................................................62Coarse Grained Soils............................................................................................................62Fine Grained Soil.................................................................................................................62OBSERVATIONS AND CALCULATIONS......................................................................64Results from Sieve Analysis................................................................................................65%age of Various Fractions...................................................................................................65Liquid Limit.........................................................................................................................65Plastic Limit.........................................................................................................................66Design of Thickness of various Layers of Flexible pavement.............................................66With Sub-base......................................................................................................................66Comments............................................................................................................................67

EXPERIMENT NO 13.............................................................................................................68Design of flexible pavement by California bearing ratio method............................................68

Code:....................................................................................................................................68Objectives:............................................................................................................................68Need and Scope:...................................................................................................................68Apparatus:............................................................................................................................68Procedure:............................................................................................................................68Definition of CBR................................................................................................................68CBR Test Procedure 1:.........................................................................................................69CBR Test Procedure 2:.........................................................................................................70Undisturbed specimen..........................................................................................................70Dynamic Compaction...........................................................................................................70Static compaction.................................................................................................................70Procedure for Penetration Test.............................................................................................71


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Observation and Recording..................................................................................................71For Dynamic Compaction....................................................................................................71For static compaction...........................................................................................................71For penetration Test.............................................................................................................72Comments:...........................................................................................................................72

Experiment No 15....................................................................................................................73Standard test method for use of dynamic cone penetrometer in shallow pavement applications..................................................................................................................................................73

Scope:...................................................................................................................................73Significance and Use:...........................................................................................................73Apparatus:............................................................................................................................73Procedure:............................................................................................................................74Testing a Surface Layer:......................................................................................................74Testing Below a Bound Layer:.............................................................................................75Testing Sequence:................................................................................................................75 Dropping the Hammer...................................................................................................75 Depth of Penetration.....................................................................................................75 Refusal:.........................................................................................................................75 Extraction......................................................................................................................75Data Recording:....................................................................................................................75Calculations and Interpretation of Results:..........................................................................76Comments............................................................................................................................76


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Table of Figure

Figure 1 (Core Cutter Apparatus)...............................................................................................9

Figure 2 (Los Angeles Abrasion Testing Machine).................................................................10

Figure 3 (Ductility Testing Machine).......................................................................................10

Figure 4 (Open Cup Flash & Fire point Apparatus)................................................................11

Figure 5 (Marshal Stability Apparatus)....................................................................................11

Figure 6 (Penetrometer)...........................................................................................................12

Figure 7 (Pycnometer)..............................................................................................................12

Figure 8 (Asphalt Centrifuge Extractor)..................................................................................12

Figure 9 (Flakiness & Elongation Index Apparatus)...............................................................13

Figure 10 (Screen Shaker)........................................................................................................13

Figure 11 (Sieve Shaker)..........................................................................................................14

Figure 12 (Water Bath)............................................................................................................14

Figure 13 (Sample splitter).......................................................................................................14

Figure 14 (Rounded aggregates)..............................................................................................15

Figure 15 (Angular shape).......................................................................................................16

Figure 16 (Flaky & Elongated)................................................................................................16

Figure 17 (Length/Elongation Index Gauge)...........................................................................16

Figure 18 (Performance)..........................................................................................................17

Figure 19 (Sieves)....................................................................................................................21

Figure 20 (Los Angeles Abrasion Apparatus)..........................................................................21

Figure 21 (Performance)..........................................................................................................22

Figure 22 (Bituminous materials)............................................................................................25

Figure 23 (Types of Crush)......................................................................................................36

Figure 24 (Apparatus)..............................................................................................................40

Figure 25 (Briquet Apparatus).................................................................................................43

Figure 26..................................................................................................................................56


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Figure 27(Sieve Test)...............................................................................................................58

Figure 28 (Plastic Limit)..........................................................................................................59

Figure 29 (Casagrande)............................................................................................................60

Figure 30 (Layers of Flexible Pavement).................................................................................65

EXPERIMENT NO 1 Layout of Highway & Traffic Engineering Lab

Dated: 10-02-2016


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List of Laboratory Apparatus 1) Core Cutter Apparatus2) Los Angeles Abrasion Testing Machine3) Ductility Testing Machine4) Marshal Stability Apparatus5) Open Cup Flash & Fire Point Apparatus6) Penetrometer7) Pycnometer8) Asphalt Centrifuge Extractor9) Flakiness & Elongation Index Apparatus10) Screen Shaker11) Sieve Shaker12) Water Bath13) Sample Splitter

Core Cutter Apparatus To cut/drill sample cores from flexible of rigid pavements mainly for test sample extraction purposes. It uses diamond bits to cut through the structure and collect sample cores in core barrel. The apparatus includes drilling equipment, core barrel, core retrieval tool & compaction.

Figure 1 (Core Cutter Apparatus)


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Los Angeles Abrasion Testing Machine The Los Angeles (L.A.) abrasion test (Figure 1) is a common test method used to indicate aggregate toughness and abrasion characteristics. The machine consists of a rolled steel drum having an inside dia. of 711 mm and internal length 508 mm. The drum is rotated by a speed reducer driven by an electric motor at a speed of between 31 and 33 r.p.m.

Figure 2 (Los Angeles Abrasion Testing Machine)

Ductility Testing Machine The device is used for determining the ductility of bituminous materials by measuring the elongation of briquette mold with molten bitumen in it. It is designed for testing 3 specimens simultaneously. Internal tank is made of stainless steel. The Internal tank is made of stainless steel. The bath is fitted with an immersion heater in order to obtain (in normal conditions), the 25°C test temperature.


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Figure 3 (Ductility Testing Machine)

Open Cup Flash & Fire Point Apparatus Measuring a flash point using an open cup method is, as the name suggests, conducted in a vessel which is exposed to the air outside. The temperature of the substance is gradually raised and an ignition source is passed over the top of it, until it reaches a point at which it “flashes” and ignites.

Figure 4 (Open Cup Flash & Fire point Apparatus)

Marshal Stability Apparatus The test is applicable to hot mix designs using bitumen and aggregates up to a maximum size of 25mm. In this method, the resistance to plastic deformation of cylindrical specimen of bituminous mixture is measured when the same is loaded at periphery at 5 cm per min. This test procedure is used in designing and evaluating bituminous paving mixes.


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Figure 5 (Marshal Stability Apparatus)

Penetrometer An instrument used for determining the consistency or hardness of a substance by measuring the depth or rate of penetration of a rod or needle driven into it by a known force. A penetrometer is a device to test the strength of a material.

Figure 6 (Penetrometer)

Pycnometer The pycnometer is a flask with a close-fitting ground glass stopper with a fine hole through it, so that a given volume can be accurately obtained.

Figure 7 (Pycnometer)


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Asphalt Centrifuge Extractor Centrifuge Extractors are used for quantitative determination of bitumen content in paving mixtures. These units require a relatively short processing time, which includes weighing the asphalt sample, heating the sample slightly until it starts crumbling, cooling the sample, placing it in the centrifuge extractor's rotor bowl and then adding solvent.

Figure 8 (Asphalt Centrifuge Extractor)

Flakiness & Elongation Index Apparatus The Flakiness and Elongation Index Test Gauges is used to estimate the applicability of coarse aggregate used in the cement and concrete mixture, it can determine the percentage of the aggregate that over than 4.75mm size (needle or flake). Aggregates which are flaky and/or elongated will often lower the workability of a concrete mix and may also affect long term durability. In bituminous mixtures, this apparatus can test the thickness and length thus to check flakiness and elongation index of the aggregate respectively.

Figure 9 (Flakiness & Elongation Index Apparatus)

Screen Shaker A screening machine consist of a drive that induces vibration, a screen media that causes particle separation, and a deck which holds the screen media and the drive and is the mode of transport for the vibration. It is used for aggregate separating it into multiple grades by particle size.


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Figure 10 (Screen Shaker)

Sieve Shaker A sieve shaker is a machine designed to hold and agitate a stack of sieves for the purpose of separating a soil or other granular material sample into its component particles by size. The stack of sieves is composed of sieves of different sizes.

Figure 11 (Sieve Shaker)

Water Bath A container of water heated to a given temperature, used for heating substances placed in smaller containers.


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Figure 12 (Water Bath)

Sample splitter Sample Splitter is the most universally used sampling device for preparing representative splits of dry, free-flowing granular product. The technique is rapid and the equipment is economical.

Figure 13 (Sample splitter)

EXPERIMENT NO 2 Determination of the flakiness and elongation index for the given

aggregate sample.

Dated: 17-02-2016

Scope & significance:

This test is used to determine the particle shape of the aggregate and each particle shape being preferred under specific conditions.

The significance of flakiness & elongation index is as follows;

The degree of packing of the particles of one size depends upon their shape.


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Code: BS-812


Due to high surface area to volume ratio, the flaky and elongated particles lower the workability of concrete mixes.

Flaky and elongated particles are considered undesirable for base coarse construction as they may cause weakness with possibilities of braking down under heavy loads.

BS-1241 specifies a Flakiness index not exceeding 30% irrespective of the aggregate size.

Maximum permitted Elongated index is 35, 40 or 45% for aggregate sizes 2 ½’’ – 2’’, 1 ½’’ – ¾’’ & ½’’ – 3/8’’

Both Flakiness and Elongation tests are not applicable to sizes smaller then 6.3mm i.e. ¼’’ sieve.

Related Theory:

Shapes of Particles: 1. Rounded (river gravel)2. Flaky (laminated rock)3. Elongated4. Angular( crushed rock)

Preferred use of each shape: Rounded aggregates are preferred in concrete roads (rigid pavements) as the workability of concrete increases due to the less friction between the surfaces.

Angular shape of the particles is desirable in granular base coarse(flexible pavement) due to better interlocking and increased stability.

Flaky and Elongated particles are considered as a source of weakness.

Apparatuses:

a) Thickness/Flakiness Index Gauge b) Length/Elongation Index Gaugec) Aggregate sample to be tested


17(b)

Figure 14 (Rounded aggregates)

Figure 15 (Angular shape)

Figure 16 (Flaky & Elongated)

http://civilengineerspk.com/wp-content/uploads/2014/04/Round-Gravel-20-40mm1.jpg

http://civilengineerspk.com/wp-content/uploads/2014/04/spey_chip_104.jpg

http://civilengineerspk.com/wp-content/uploads/2014/04/Flat_elongated.jpg

http://civilengineerspk.com/wp-content/uploads/2014/04/H-16841.jpg

http://civilengineerspk.com/wp-content/uploads/2014/04/images.jpg


Flaky: A flaky particle is the one whose least dimension (thickness) is than 0.6 times the mean

size. These are the materials of which the thickness is small as compared to the other two

dimensions. Limit of flaky particles in the mixes is 30%. If the flaky particles are greater than 30%

then the aggregate is considered undesirable for the intended use.

Flakiness index: It is the percentage by weight of flaky particles in a sample.

Elongated particles: These are the particles having length considerably larger than the other two dimensions and it is the particle whose greater dimension is 1.8 times its mean size.

Limit of elongated particles in the mixes is 45%. Thus, if the elongated particles are greater than 45%, then the aggregate is considered undesirable for the intended use.

Elongation index: It is the percentage by weight of elongated particles in a sample. The Elongated index is calculated by expressing the weight of Elongated particles as percentage of total weight of the sample.

Procedure: Perform the sieve analysis on the given aggregate sample/ The aggregates are then arranged in the into a number of closely limited particle size

groups -stored on the test sieves into a number of closely limited particle size groups – 2 ½’’ – 2’’, 1 ½’’ – ¾’’ & ½’’ – 3/8’’

Each group (fraction) is weighed and tested for thickness on appropriate opening of the thickness gauge by passing each particle through slot of specified thickness along least dimension.

The weight of particles passing the thickness gauge is recorded for each fraction. This is the weight of flaky particles.

The flakiness index is calculated by expressing the weight of flaky particles as a percentage of total weight of the sample.


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Precautions: 1. While sieving, care must be taken that the particles that are chocked in the sieve must not

be forced down into the next sieve. Such particles should be pushed back into the same sieve.

2. While placing different fractions on the table, place them some distance apart so that no two fractions may get mixed.

3. Be careful while selecting the opening of the flakiness and elongation gauges for any particular fraction.

Performance: Following images were taken during the performance of experiment in laboratory.

Sieve Analysis: Sample weight = g

Sieve sizePassing(inch)

Sieve sizeRetained

(inch)

Weight Retained

(gm)

Percentage Retained (%)

Cumulative Weight

Retained (%)

Percentage passing

(%)

2.5 2

2 1.5

1.5 1

1 3/4

3/4 1/2

1/2 3/8

3/8 1/4

∑=


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Figure 18 (Performance)


Calculations for flaky particles:


Sieve sizeRetained

(inch)

Weight Retained

(gm)

Percentage Retained

(%)

Weight of Flaky

particles (gm)

Individual Flakiness Index (%)

WeightedFlakiness Index (%)

2.5 2

2 1.5

1.5 1

1 3/4

3/4 1/2

1/2 3/8

3/8 1/4

∑ = ∑ =

Calculations for elongated particles:


Sieve sizeRetained

(inch)

Weight Retained

(gm)

Percentage Retained

(%)

Weight of Elongatedparticles

(gm)

Individual Elongated Index (%)

WeightedElongated Index (%)

2.5 2

2 1.5

1.5 1

1 3/4

3/4 1/2

1/2 3/8

∑ = ∑ =


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Comments:

EXPERIMENT NO 3 Standard test method for resistance to degradation of coarse aggregates by abrasion and impact in Los Angeles abrasion

machine.

Code: ASTM-C-131 Dated: 24-02-2016 AASHTO-T-96

Scope & Significance:

Los Angeles abrasion test is a common test used to indicate aggregate toughness and abrasion characteristics.

This test is used to assess the hardness of the aggregate used in road construction. The road aggregate is subjected to wearing action by the moving traffic and therefore resistance to wear or hardness is an essential property of the aggregate. The aggregate should be hard enough to resist abrasion due to traffic.


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Los Angeles Abrasion test is used to find out the percentage wear due to relative rubbing action between aggregate and steel balls used as abrasive charges. Pounding action of these balls also exists while conducting the test. The test is considered more dependable as rubbing and pounding action simulate field conditions.

AASHTO T 96, recommendations are that Base Course has a percent wear of 40% or less. For Sub-base Course the requirement is 50% or less. And for wearing surface it is 30%.

Notes:

Larger the LAA value, softer will be the aggregate and vice versa.

If we have two samples to be used in the wearing surface having LAA value of 0% & 10%, then we should use the one having LAA value of 10% (note this is true only for wearing surface and the opposite is true for sub-grade, sub-base and base coarse). This is because, even though 0% will provide a good hard surface but its coefficient of friction will be too high and it will severely damage the tires.

If two different samples are obtained from the same source, then the results of the LAA value will be same for both of the samples because LAA value is a material property.

Related theory:

Abrasion:

It is defined as the, “resistance of a material against wear, scratching or degradation.” OR abrasion means “breaking of surface”

Pounding action:

Pounding means impact. Striking action of an object on a surface for a short instant of time is called the pounding effect.

Los Angeles abrasion value:

It is an indicative of the abrasion strength of the aggregates. It can be computed by using the relationship;

Los Angeles Abrasion Value=Orignal Weight−Final WeightOrignal Weight

×100


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Where,

Final weight = Weight retained on sieve #12

Apparatus: Los Angeles Abrasion machine – consists of a hollow

steel cylinder closed at both ends, having inside diameter of 28’’ and inside length of 20’’. The cylinder is mounted on stub shafts in such a way that it rotates about horizontal axis at 30-33 rpm.

An opening in the cylinder with a dust tight cover is provided for the introduction of test sample. A steel shelf extending full length of the cylinder and projecting 3.5’’ inward is mounted on interior surface of the cylinder.

Abrasive charges (consisting of steel spheres 1 27/32’’ in diameter.

Sieves confirming to ASTM Standards.

Balance

Procedure:

The sample taken should be representative and confirming to any of the grading given in the table.

The sample is placed in the cylinder along with the abrasive charges and the machine is rotated for the required number of revolutions (500 – 1000).

After the required number of revolutions, material is discharged from the machine and sieved through #12 US sieve.

Wash the material coarser than #12 sieves, oven dry and weigh. Then compute the LAA value

Los Angeles Abrasion Value=Orignal Weight−Final Weight

Orignal Weight×100

Where,

Final weight = Weight retained on sieve #12


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Figure 19 (Los Angeles Abrasion Apparatus)

Figure 20 (Sieves)


Notes:

If a large rock piece is provided for the test, first of all crush it then sieve it and then proceed in the same manner.

If the amount of aggregate collected in the lower sieves is less than the required amount, then crush the aggregate in the higher sieves to get the required quantity in the lower sieves.

If the amount of aggregate collected in the top sieves is less than the required amount, then sieve more aggregate in order to collect enough quantity of aggregate.

Performance: Following pictures were taken during performing the experiment.

Grading of test sample (Los Angeles abrasion test):

Sieve sizes Weight & grading of test sample (gm.)

Passing Retained A B C D 1 2 3

3 in 2 ½ in - - - -2500±5

0- -

2 ½ in 2 in - - - -2500±5

0- -

2 in 1 ½ in - - - -5000±5

05000±5

0-

1 ½ in 1 in1250±20

- - - -5000±5

05000±25

1 in ¾ in1250±20

- - - - - 5000±25

¾ in ½ in1250±10

2500±10

- - - - -

½ in 3/8 in 1250 2500±1 - - - - -


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Figure 21 (Performance)


±10 0

3/8 in ¼ in - -2500±1

0- - - -

¼ in #4 - -2500±1

0- - - -

#4 #8 - - -5000±1

0- - -

Total weight required5000±10

5000±10

5000±10

5000±10

10000±100

10000±75

10000±50

Abrasive Charges No. of Revolutions Number of Spheres Weight of Charges (gm.)

A

500

12 5000±25B 11 4584±25C 8 3330±20D 6 2500±251

100012 5000±25

2 12 5000±253 12 5000±25

Observations & Calculations:

Grading used for the test =

Number of abrasive charges used =

Original weight of the sample, W1 (gm.) =

Final weight after test (retained on sieve #12), W2 (gm.)=

Los Angeles Abrasion Value=Orignal Weight−Final WeightOrignal Weight

×100

LLA= %

Comments:


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EXPERIMENT NO 4 Penetration Test on Bituminous Materials.

Dated: 02-03-2016 AASHTO-T-96


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Table 1 (Types of Pavement)

Code: ASTM -D-5

Sr No. Type of Pavement Max. permissible

abrasion value in %1 Water bound macadam sub base course 60

2 WBM base course with bituminous surfacing 50

3 Bituminous bound macadam 50

4 WBM surfacing course 40

5 Bituminous penetration macadam 40

6 Bituminous surface dressing, cement concrete surface course 35


Penetration: Consistency of a bituminous material expressed as the distance in tenths of a millimeter that a standard needle vertically penetrates a sample of the material under known conditions of loading, time, and temperature.

Grades of Bitumen: Bitumen is usually characterized in the following three types of grades;

1. Viscosity grades2. Penetration grades3. Density grades

Scope: 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. 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.

Specifications: AASHTO T 49 and ASTM D 5-97: Penetration Of Bituminous Materials

Apparatus:

Penetrometer Container

Table 2 (Penetration)

PenetrationDiameter

(mm)Internal Depth

(mm) 200 55 35 200-350 55 70


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Figure 22 (Bituminous materials)


Water bath with at least 10 liter capacity. Heater Thermometer Specified needle Transfer tray

Procedure:

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.

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.

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

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.

Take at least three readings. At least two samples should be tested for grade determination.

Test Specifications: A load of 100 grams applied for 5seconds at 25C is standardized for the test. Other test conditions are given in the table.

Table 3 (Test Condition)

Temperature(oC)

Load(gm.)

Time(sec)

0 200 604 200 6045 50 5

46.1 50 5

Report: Report to nearest whole unit the average of three penetrations whose values do not differ by more than the following:

Penetration 0 To 49 50 To 149 150 To 249 250 To 500


28


Maximum Difference Between Highest And Lowest Penetration.

2 4 12 20

Calculation and Observation:

Pouring Temperature = CPeriod of Cooling in Room = hourRoom Temperature = CWater Bath Temperature = C

S No.Penetration In 10th Of (Mm)

GradeReading Reading Reading

1.2.

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

heated to 60o C above the expected softening point. The sample is covered loosely against dust The weight of needle and spindle assembly should be accurate i.e, 100 ± 0.05 grams. Verticality of the needle should be ensured. Readings taken on a single sample should be at least 10 mm apart.

Comments:

EXPERIMENT NO 05 Specific Gravity Test on Bituminous Materials.


29Code: ASTM-D-1180



Specific Gravity: The specific gravity of semi-solid bituminous material, asphalt cements, and soft tar pitches shall be expressed as the ratio of the mass of a given volume of the material at 25 °c to that of an equal volume of water at the same temperature.

Scope & Significance: Specific gravity of a bitumen binder is a fundamental property frequently required as an

aid in classing binders for use in paving jobs. Bitumen weights sometimes have to be converted into volumes for asphalt concrete mix

design calculations for which a knowledge of specific gravity is essential. Specific gravity is also used in identifying the source of bitumen binder. Bitumen binder has specific gravity in the range of 0.97 to 1.02. In case bitumen contains mineral impurities the specific gravity will be higher. Thus it is

possible for a quantitative extraction of mineral impurity in bitumen.

Apparatus: Pycnometer — glass, consisting of a cylindrical or conical vessel. Water bath, constant-temperature, capable of maintaining the temperature within 0.1 °c

of the test temperature. Thermometers — calibrated liquid-in-glass, total immersion type, of suitable range. Balance — a balance conforming to the requirements of aashto. Distilled water — freshly boiled and cooled distilled water shall he used to fill the

pycnometer and the beaker

Procedure:

Preparation of Sample: 1- Heat the sample with care, stirring to prevent local overheating until the sample has

become sufficiently fluid to pour. While heating, keep in mind the following considerations;

i)- In no case should the temperature be raised to more than 56 °c above the expected softening point for tar, or to more than 111°c above the expected softening point for asphalt.

ii)- Do not heat for more than 30 minutes over a flame or hot plate or for more than 2 hours in an oven, and avoid incorporating air bubbles in the sample.


30


2- Thoroughly clean, dry, and weigh the pycnometer to the nearest 1 mg. Designate this mass as ‘a’.

3- Then fill the beaker with freshly boiled distilled water, placing the stopper loosely in the pycnometer. Place the pycnometer in the beaker and press the stopper firmly in place. Return the beaker to the water bath, and allow the pycnometer to remaining the water bath for a period of not less than 30 minutes. Remove the pycnometer, immediately dry the top of the stopper with one stroke of a dry towel, then quickly dry the remaining outside area of the pycnometer and weigh to the nearest 1 mg. Designate the mass of the pycnometer plus water as ‘b’.

4- Pour enough sample into the clean, dry, warmed pycnometer to fill it about three-fourths of its capacity. Take precautions to keep the material from touching the sides of the pycnometer above the final level, and to prevent the inclusion of air bubbles. Allow the pycnometer and its contents to cool to ambient temperature for a period of not less than 40 minutes, and weigh with, the stopper to the nearest 1 mg. Designate the mass of the pycnometer plus sample as ‘c’.

5- Remove the beaker from the water bath. Fill the pycnometer containing the asphalt with freshly boiled distilled water, placing the stopper loosely in the pycnometer. Do not allow any air bubbles to remain in the pycnometer. Place the pycnometer in the beaker and press the stopper firmly in place. Return the beaker to the water bath. Allow the pycnometer to remain in the water bath for a period of not less than 30 minutes. Remove the pycnometer from the bath. Dry and weigh using the same technique and timing as that employed in # 2. Designate this mass of pycnometer plus sample plus water as ‘d’.

Calculations:

Calculate the specific gravity to the nearest third decimal as follows:

Where,

A = mass of Pycnometer (+ stopper)B = mass of Pycnometer filled with water.C = mass of Pycnometer partially filled with asphalt, andD = mass of Pycnometer + asphalt + water

Observations & Results:


31

Specific Gravity= (C−A )[(B−A )−(D−C ) ]


Gro

upWeights

Pycnometer, (A)

Pycnometer + Water, (B)

Pycnometer + Asphalt,

(C)

Pycnometer +

Water + Asphalt,

(D)(gm) (gm) (gm) (gm)

1

Comments:

EXPERIMENT NO 6 Determination of Angularity Number for the Given Aggregate

Sample.

Dated: 09-03-2016


32

Code: ASTM-C-152

Specific Gravity= (C−A )[(B−A )−(D−C ) ]


AASHTO-T-304

Objectives: This test is also carried out for determining shape of the aggregates. Based upon shape the aggregates may be classified as Rounded, Angular or Flaky. Angular particles possess well defined edges formed at the intersection of roughly planer faces and are commonly formed in aggregates prepared by crushing of rocks.

Angularity in general is the absence of rounding of particles of an aggregate. This test is performed to determine the angularity number i.e. the absence of roundedness or the degree of angularity of the aggregate specimen.

Related Theory:

Shapes Of Particles:

The Usual Shapes of the particles are; Rounded (River Gravel) Flaky (Laminated Rock) Elongated Angular (Crushed Rock)

Angularity: It is the absence of roundness. An aggregate particle, which is more rounded, is less angular and vice versa.

Angularity Number: Angularity number of an aggregate is the amount (to the higher whole number) by which the percentage of voids in it after compacting in a prescribed manner exceeds 33.

Where, “33” is the percentage of volume of voids, in a perfectly rounded aggregate. “67” is the percentage of volume of solids in a perfectly rounded aggregate.The value of angularity number generally lies between 0 & 11. In road construction angularity number of 7 – 10 is generally preferred.

Significance: The degree of packing of particles of single sized aggregate depends upon the

angularity of aggregate. The angularity of the aggregate can be estimated from the properties of voids in a

sample of aggregate compacted in a specified manner.


33


The angularity number ranges from 0 for a highly rounded grave to about 11 for freshly crushed angular aggregates.

Higher the angularity number, more angular and less workable is the concrete mix. In cement concrete roads (rigid pavements) rounded aggregates are preferred because of

better workability and higher strength. In bituminous or water bound macadam construction (like flexible pavements), angular

aggregates with high angularity number are preferred because of high stability due to better interlocking and friction.

Higher the angularity number, more angular and less workable is the concrete mix. In road construction, angularity number of 7 -10 is generally preferred.

Apparatus:

1. A metal cylinder of about 3-liter capacity.2. Temping rod of circular cross-section, 16mm Φ, 60cm in length. Rounded at one end.3. A metal scoop.4. A weighing balance.

Procedure:

This procedure is for aggregate size ¾ to No.4. If aggregate is coarser than ¾, a cylinder of large capacity shall be required but amount of compactive effort or energy should be proportional to the volume of the cylinder.

10 Kg of the sample is taken for the test. The material should be oven dried. The aggregate is compacted in three layers, each layer being given 100 blows using the standard tamping rod at a rate of 2 blows/second by lifting the rod 5 cm above the surface of the aggregate and then allowing it to fall freely. The blows are uniformly distributed over the surface of the aggregate. After compacting the third layer, the cylinder is filled to overflowing and excess material is removed off with temping rod as a straight edge.

The aggregate with cylinder is then weighed. Three separate determinations are made and mean weight of the aggregate in the cylinder is calculated.

Calculation & Results:

Method – 1 Add measured quantity of water in the compacted aggregate till all the voids

are filled and water appears to the surface. Volume of water added is approximately equal to the volume of voids in the compacted aggregate.


34


Method – 2

Where,W = mean weight of the aggregate filling cylinder.C = Weight/Volume of water that can completely fill the cylinder (= 3 liters = 3000 ml – in our lab)

Gs = Specific Gravity of the aggregate.

Notes: Method – 1 determines the angularity number from the solids point of view.

Method – 2 determines the angularity number from the voids point of view.

Computations & Results:

Specific Gravity Of The Aggregate 2.67

Total Volume Of The Cylinder

Cylinder Diameter 6”

Height Of Cylinder 12”

Sr. #

Weight Volume Of Water Added(Ml)

Angularity NumberEmpty

Cylinder(Kg)

Cylinder + Aggregate

(Kg)

Aggregate(Kg)

Method # 1

Method # 2

1

Comments:


35

Angularity Number=Volume of Water AddedTotal Volume

×100−33

Angularity Number=67−100 WCGs


EXPERIMENT NO 7 Specific Gravity (Relative Density) and Water Absorption Test

for Aggregates.

Dated: 09-03-2016

AASHTO-T-85


36

Code: ASTM-D-127


Related Theory:

Specific Gravity: It is defined as ratio of weight of solid to the weight of an equal volume of gas free distilled water (no dissolved air/impurities) at a stated temperature.

Water Absorption: It is the ratio of weight of water absorbed to the weight of dry sample expressed as a percentage. It will not include the amount of water adhering to the surface of the particles

Coarse Aggregates: Any material which is retained on BS sieve #4 (ASTM sieve 4.75mm) is known as coarse aggregate.

Fine Aggregates: Any material which is passing BS sieve #4 (ASTM sieve 4.75mm) is known as fine aggregate.

Saturated Surface Dry (S.S.D.) Condition: It is the condition related with the aggregate particles in which the permeable pores of the aggregate particles are filled with water but without free water on the surface of the particles.

Oven Dried Specific Gravity: It is the ratio of the oven dried density of the aggregate to the density of the gas free distilled water at a standard temperature (i.e. 4 oC).

Saturated Surface Dry (S.S.D) Specific Gravity: It is the ratio of the saturated surface dry density of the aggregate to the density of the gas free distilled water at a standard temperature (i.e. 4 oC).

Apparent Specific Gravity: It is the ratio of the apparent density of the aggregate to the density of the gas free distilled water at a standard temperature (i.e. 4 oC).

Types Of Crush Available In Pakistan:

Sargodha Crush Sargodha crush possess the following properties;


37


Greenish/Dark gray in color High strength Usually elongated particles

Margalla Crush Margalla crush possess the following properties;

Light gray in color Low in strength

Sakhi Sarwar Crush Sakhi sarwar crush possess the following properties;

Whitish in color

Significance: In this test method we will determine the relative density (i.e. specific gravity) and the water absorption of the coarse aggregates.

The knowledge of the specific gravity is important for the concrete technologist to determine the properties of concrete made from such aggregates.

It is used for the calculation of the volume occupied by the aggregates in various mixes and generally it ranges from 2.5 to 3.

The pores at the surface of the particles affect the bond between the aggregate and the cement paste thus influences the concrete strength. Smaller the number of pores, higher will be the specific gravity hence more will be the bond strength and more concrete strength.

Though higher specific gravity of aggregate is considered as an indication of its high strength; it is not possible to judge the suitability on this basis alone without finding other mechanical properties like aggregate abrasion value etc.

Water absorption is a measure of porosity of aggregates and its resistance to frost action.

Higher water absorption means more pores hence aggregate will be the considered as weak.


38

Figure 23 (Types of Crush)


Water absorption value ranges from 0.1 – 2.0% for aggregate normally used in roads surfaces.

Aggregates with water absorption up to 4.0% are acceptable in base coarse.

Apparatus:

Balance 5 Kg capacity readable to 0.5g.

Sample container in the form of a wire mesh bucket of capacity 4000 – 7000 cm3 and not more than 6.3mm mesh.

Suitable arrangement for suspending the container in water from center of the balance.

A container for filling water and suspending the wire mesh bucket.

Shallow tray and absorbent cloth.

Thermostatically controlled oven.

Sample: Take representative sample. Reject all material passing #4, weight of sample to be used for the test would depend upon the nominal maximum size as given in table below.

Nominal Maximum Size

(Mm) 12.5 19 25 37.5 50 63 75 90

(In.) ½ ¾ 1 1 ½ 2 2 ½ 3 3 ½

Maximum Sample Wt.

(Kg)2 3 4 5 8 12 18 25

Procedure: Thoroughly wash the aggregates to remove any dust. Oven dry and cool the

aggregates for 1 to 3 hours and then immerse in water for 24 hours.

Remove the specimen from water and roll it in a large absorbent cloth until all visible films of water are removed.

Weight the specimen in saturated surface dry conditions.


39


Place the saturated surface dry specimen in wire mesh bucket and weight it in water. Shake the bucket to remove all entrapped air before weighing.

Dry the sample to constant weight in oven, cool and weigh.

Observations:

Weight of oven dried aggregate in air (Kg) A = Weight of saturated surface dry aggregate in air (Kg) B = Weight of saturated aggregate in water (Kg) C=

Oven dried specific gravity Sd = A / (B – C) = Saturated surface dry specific gravity Ss = B / (B – C) = Water absorption, W.A. = [(B – A) / A] X 100 = Apparent specific gravity = A / (A – C) =

Comments:

EXPERIMENT NO 08 Softening Point of Bitumen



40

Code: ASTM-D-36


Softening Point: The softening point is defined as the mean of the temperatures at which the bitumen

disks soften and sag downwards a distance of 25 mm under the weight of a steel ball.

Scope & Significance:

1- This method is useful in determining the consistency of bitumen as one element in establishing the uniformity of shipments or sources of supply.

2- Softening point is the temperature at which the bituminous binders have an equal viscosity (i.e. the consistency of all the grades will be same at the softening point e.g. if two samples have softening points of 40 °c and 80 °c respectively, both will have the same consistency at their softening point.).

3- The test gives an idea of the temperature at which the bituminous materials attain a certain viscosity.

4- Bitumen with higher softening point may be preferred in warmer places.

5- Softening point should be higher than the hottest day temperature, which is anticipated in that area otherwise bitumen may sufficiently soften and result in bleeding and development of ruts.

Apparatus:

Ring — A brass shouldered ring.

Ball— A steel ball, 9.53 mm (3/8”) in diameter, weighing between 3.45 and3.55 grams.

Ball Centering Guide — A guide for centering the ball and made of brass.

Ring Holder — The rings shall be supported on a brass ring holder.Brass Pouring Plate — A flat, smooth brass plate approximately 75 by 50 mm that has been treated to prevent the bituminous material from adhering to it. A suitable treatment is to coat the plate just before use with a thin layer of a mixture of glycerin and dextrin, talc, or china clay.Bath Thermometers — having a range from -2 to +80°C. .


41


Figure 24 (Apparatus)

Procedure:

A ) - For Materials Having Softening Points 80°C Or Below

Assemble the apparatus with the rings, ASTM thermometer 15 °c or i5 °f, and ball centering guides in position and fill the bath with freshly boiled water to a depth of not less than 102mm and not more than 108mm.

Maintain the bath temperature at 5 ± 1°c for 15 min, placing the test container in ice water if necessary. Using forceps, place a ball, previously adjusted to the bath temperature, in each ball-centering guide.

Apply heat in such a manner that the temperature of the liquid is raised 5°c/min. Avoid the effect of drafts, using shields if necessary. (rigid adherence to the prescribed rate of heating is absolutely essential for reproducibility of results. Either a gas burner or electric heater may be used; however, the latter must be of the low-lag, variable output type to maintain the necessary rate of heating.)

The rate of rise of temperature shall be uniform and shall not be averaged over the period of the test. The maximum permissible variation of any 1-mm period after the first 3 mm shall be ± 0.5°c. Reject all tests in which the rate of rise does not fall within these limits.

Record for each ring and ball the temperature shown by the thermometer at the instant the specimen surrounding the ball touches the bottom plate. Make no correction for the emergent stem of the thermometer. If the difference between the values obtained in the duplicate determinations exceeds 1°c repeat the test.


42


B) - For Materials Having Softening Points Abo ve 80°C:

Follow the same procedure as described above, except use USP glycerin instead of water and use ASTM thermometer l6°c or 16°f. The starting temperature of the glycerin bath shall be 32°c.


Sr. #Softening Point Mean

(°C) (°C)

1

2

Comments:

EXPERIMENT NO 09 To Perform Ductility Test on Asphalt

Dated: 13-04-2016

AASHTO-T-51


43

Code: ASTM-D-113


Related Theory:

Ductility: The ductility of a bituminous material is defined as the distance in centimeters, to which it will elongate before breaking when two ends of a briquet specimen of the material, are pulled apart at a specified speed and a specified temperature.

Unless otherwise specified, the test shall be made at a temperature of 25 ± 0.5 °C and with a speed of 5 cm/min ± 5.0 %. At other temperatures the speed should be specified.

Ductility of asphalt depends upon the grade of asphalt, pouring temperature, dimensions of briquet, test temperature, rate of pull and levelling of mold.

Importance of Ductility: The ductility of a bitumen specimen tells us about

1- Tensile strength of bitumen2- Grade of sample (ductility grade)

Scope & Significance: 1- This test method provides measure of tensile properties of bituminous materials

and may be used to measure ductility for specification requirements.2- Bituminous materials used in pavement construction should possess sufficient

ductility otherwise the pavement would crack due to temperature or traffic stresses and may render the pavement pervious and damage the pavement structure.

3- The ductility value varies from 5 to over 100 cm’s.4- Several agencies have specified minimum ductility values for various types of

bitumen pavements. However, a ductility of 100 cm’s is specified generally for bituminous construction.

5- Roads expand at daytime while they contract at night. So, if the bitumen is not adequately ductile cracking will occur.

6- More than one grade may be used in the same project. For example; we may use grade 80/100 on the main traffic lane and lower grades on the arteries.

Apparatus:

Mold — the mold is made of brass, the ends being known as clips, and the middle parts asides of the mold.

Water Bath — the water bath shall be maintained at the specified test temperature, varying not more


44Figure 25 (Briquet Apparatus)


than 0.1 °C from this temperature. The volume of water shall be not 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.

Testing Machine — For pulling the briquet of bituminous material apart, any apparatus may be used which is so constructed that the specimen will continuously immersed in water, while the two clips are pulled apart at a uniform speed, as specified, without undue vibration.

Thermometer — A thermometer having a range -8 to 32 °C (18 - 89 °F)

Procedure:

Assemble the mold on a brass plate. Thoroughly coat the surface of the plate and interior surfaces of the sides of the mold with a thin layer of a mixture of glycerin and 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.

Carefully heat the sample to prevent local overheating until it has become sufficiently fluid to pour.

Strain the molten sample through a # 50 sieve. After a thorough stirring, pour it into the mold. In filling the mold, take care not to disarrange the parts and thus distort the briquet.

Infilling, pour the material in a thin stream hack 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 from 30 to 40 minutes and then place it in the water bath maintained at the specified temperature of test for 30 minutes; then cut off the excess bitumen with a hot straight edged knife or spatula to make the mold just level full.

Place the brass plate and mold, with briquet specimen, in water bath and keep at the specified temperature for a period of from 85 to 95 minutes. Then remove the briquet from the plate, detach the sidepieces, and immediately test the briquet.

Testing: Attach the rings at each end of the clips to the pin or hooks in the testing machine and pull the two clips apart at a uniform speed specified until the briquet ruptures. Measure the distance in centimeters 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 DEPARTMENT OF CIVIL ENGINEERING | THE UNIVERSITY OF LAHORE

45


the specimen both above and below it by at least 2.5 cm and shall be kept continuously at the temperature specified.

If the bituminous material comes in contact with the surface of the water or the bottom of the bath, the test shall not be considered normal. Adjust the specific gravity of the bath by the addition of either methyl alcohol or sodium chloride so that the bituminous material neither comes to the surface of the water, nor touches the bottom of the bath at any time during the test.


Sr. # DESCRIPTION RESULT1 Grade of Bitumen2 Pouring Temperature

3 Test Temperature4 Period of Cooling

a)- in Air

b)- in water bath – before trimming

c)- in water bath – after trimming

Comments:

EXPERIMENT NO 10 Flash And Fire Point Test For Asphalt By Cleveland Open Cup


46

Code: ASTM-D-92 Dated: 07-05-2015 AASHTO-T-48


Related Theory:

Flash Point: Flash point is the lowest temperature corrected to a barometric pressure of 101.3 kPa (760 mm Hg), at which application of a test flame causes the vapor of a specimen to ignite under specified conditions of test.

The material is deemed to have flashed when a large flame appears and instantaneously propagates itself over the surface of the specimen.

Note: Occasionally, particularly near the actual flash point, the application of test flame will cause the blue halo or an enlarged flame; this is not a flash and should be ignored.

Fire Point: It is the lowest temperature at which a specimen will sustain burning for 5 seconds.A flammable material is the one, which form flames, but does not sustain fire while a combustible material is the one, which sustains fire/burning.

Scope & Significance: Flash point measures the tendency of the sample to form a flammable mixture with air

under controlled laboratory conditions. It is only one of a number of properties that must be considered in assessing the overall flammability hazard of a material.

Flash point is used in shipping and safety regulations to differentiate between ‘‘flammable’’ and ‘‘combustible’’ materials.

Flash point can indicate the possible presence of highly volatile and flammable materials in a relatively nonvolatile or nonflammable material.

Fire point measures the characteristics of the sample to support combustion. Bituminous materials give rise to volatiles at high temperature, as they are basically the

hydrocarbons. These volatiles catch fire causing a flash, which is very hazardous. During construction of bituminous pavements, the engineer may restrict the mixing or

application temperatures well within the limits. The test therefore gives indication of critical temperature at and above which suitable precautions should be taken to eliminate fire hazards during use of asphalts. In other words heating should be limited to a temperature well below the flash point.


47


Asphalt Cement (AC): Asphalt Cement shall be oil asphalt or a mixture of refined liquid asphalt and refined solid asphalt, prepared from crude asphaltic petroleum. It shall be free from admixture with any residues obtained by the artificial distillation of coal, coal tar or paraffin and shall be homogeneous and free from water.

Temperature Condition * Asphalt GradeCold, mean annual air temperature

< 7 °C (45 °F)AC-10AR-400080 / 100 pen

Warm, mean annual air temperature between 7 °C (45 °F) and

24 °C (75 °F)

AC-20AR-800060 / 70 pen

Hot, mean annual air temperature> 24 °C (75 °F)

AC-40AR-800040 / 50 pen

Apparatus: Cleveland Cup Apparatus: It consists of test cup, heating plate, test flame applicator, heater, thermometer support and heating plate support.

Procedure:

Fill the cup; at any convenient temperature not exceeding 100 °C or above the softening point; so that the top of the meniscus is at the filling line.

Remove the excess sample using a pipette or other suitable device; however, if there is sample on the outside of the apparatus, empty, clean, and refill it. Destroy any air bubbles on the surface of the sample.

Lit the test flame and adjust it to a diameter of 3.8 to 5.4 mm. Apply heat initially so that the rate of temperature rise of the sample is 14 to 17 °C

per minute. When the sample temperature is approximately 56 °C below the anticipated flash point, decrease the heat so that the rate of temperature rise for 28°C before the flash point is 5 to 6°C per minute.

Starting at least 28 °C below the flash point, apply the test flame when the temperature read on the thermometer reaches each successive 2 °C mark. Pass the test flame across the center of the cup, at right angles to the diameter, which passes through the thermometer. With a smooth, continuous motion apply the flame either in


48


a straight line or along the circumference of a circle having a radius of at least 150 mm. The center of the test flame must move in a plane not more than 2.5 mm above the plane of the upper edge of the cup passing in one direction first, then in the opposite direction the next lime. The time consumed in passing the test flame across the cup shall be about one second (1 s.). During the last 17 °C rise in temperature prior to the flash point, care must be taken to avoid disturbing the vapors in the test cup by careless movements or bathing near the cup.

Record as the observed flash point the temperature read on the thermometer when a flash appears at any point on the surface of the material, but does not confuse the true flash with the bluish halo that sometimes surrounds the test flame.

To determine the fire point, continue heating so that the sample temperature increases at a rate of 5 to 6 °C. Continue the application of the test flame at 2°C intervals until the oil ignites and continues to burn for at least 5 second. Record the temperature at the point as the fire point of the oil.

Precautions: Do not breathe close to the apparatus as the fumes are injurious to health. Turn the fans off so that the fumes can be accumulated over the cup. Tip of the thermometer should not touch the bottom or sides of the cup. The operator must exercise and take appropriate safety precautions during the initial

application of the test flame, since samples containing low flash material may give an abnormally strong flash when the test flame is first applied.

Calculations and Report: Observe and record the barometric pressure at the time of the test. When the pressure differs from 760 mm Hg, correct the flash or fire point, or both, by means of the following equations:

Corrected flash or fire point, or both = C + 0.03 (760 — P) Where:C = observed flash or fire point, or both, to the nearest 2 °C, andP = Barometric pressure, mm Hg.

Record the corrected flash or fire joint value, or both, to the nearest 5 °C or 2°C.

Flash Point of Different Grades of Asphalt:

Viscosity Grades:


49


Property AC – 2.5 AC – 5 AC – 10 AC – 20 AC – 40Flash Point

COC, °C min.

163 177 219 232 232

Note: AC – 10 is most commonly used in Pakistan.


Sr.# Time (min) Temperature (C) Remarks1. 1 34 Increasing temperature2. 2 39 //3. 3 44 //4. 4 51 //5. 5 58 //6. 6 72 //7. 7 --- //8. 8 158 //9. 9 180 //10. 10 194 //11. 11 218 //12. 12 232 //13. 13 244 //14. 14 256 //15. 15 266 //16. 16 276 //

17. 17 284 //18. 18 292 //

19. 19 302Still No Flash point Came

temperature continue increasing

20. 20 312 //21./

21 316 //

22. 22 322 //23. 23 330 //24. 24 336 //25. 25 340 //26. 26 344 //27. 27 348 //


50


28. 28 351 //29. 29 356 //30. 30 359 //31. 30.30 360 //32. 31 ----- //33. 32 364 Flash Point

Graph:

Temperature Vs. Time

Results:

Flash Point = 364 °C at 34min

Fire Point = 404 °C

Comments:


51

0 5 10 15 20 25 30 350

50

100

150

200

250

300

350

400

Time ~ Temp.



52


EXPERIMENT NO 11 Marshall Method of Mix Design

Code: ASTM-D-1559 Dated: 12-05-2015

Introduction: The Marshall Method of mix design is intended both for laboratory design and field control of bituminous hot-mix dense graded paving mixtures. Originally developed by Bruce Marshall of the Mississippi State Highway Department, the US Army Corps of Engineers refined and added certain features to Marshall’s approach and it was then subsequently formalized as ASTM D 1559 and AASHTO T245.

Outline of Method:

It uses standard cylindrical test specimens (64 mm high and 102 mm in diameter). Two principal features of Marshall Method of mix design are Density Void Analysis and Stability Flow Test of compacted test specimen.

Stability of test specimens is the maximum load resistance developed by standard test specimen at 60°C in Newton.

Flow value is the total movement or displacement occurring in the specimen between no load and the point of maximum load during stability test in units of 0.25mm.

Selection and Combination of Aggregates: Selection of the aggregates to be used in a given paving mixture is a very important phase of the design phase. In normal procedure, both coarse and fine aggregates available in the near vicinity of the proposed work are sampled and carefully examined for compliance with the individual specifications for these materials. In case no suitable single aggregate is available then aggregates from several different sources may have to be blended to get the required specified specimen. The proportions selected must be within the specification and far enough from its extremes to provide room for the job mix tolerance so that when it is added or subtracted the mixture will not be outside the original specification master range. Sieve Analysis of the aggregates can most economically be used in this case as determined by AASHTO methods of T27 and T37.


53


Mineral Aggregate And Mix Composition:

Passing Sieve Designation Retained on Sieve Designation

Percent by weight

¾ in. (19.0 mm) ½ in. (12.5 mm) 0-6½ in. (12.5 mm) 3/8 in. (9.5 mm) 9-403/8 in. (9.5 mm) No.4 (4.75 mm) 9-45No.4 (4.75 mm) No. 10 (2.00 mm) 8-27

Total Coarse Aggregate No. 10 (2.00 mm) 50-65No. 10 (2.00 mm) No. 40 (0.475 mm) 6-22No. 40 (0.475 mm) No. 80 (0.177 mm) 8-27No. 80 (0.177 mm) No. 200 (0.75 mm) 5-17No. 200 (0.75 mm) ------ 5-8

Total fine aggregate & filler Passing No. 10 35-50Total mineral aggregate ------ 100

Total MixTotal mineral aggregate 92-95

Asphalt cement 5-8Total mix 100

It is obvious that the fine aggregate and coarse aggregate only, in any combination, cannot meet the requirements of the specifications for total mineral aggregate. So, mineral fillers must be used in the mixture.

Sieve Analysis Of Aggregates (Percentage Used For Experiment)

Passing Sieve Designation (Percentby

weight)

Retained on Sieve

Designation (Percent by

weight)

AGGREGATE TYPE

COARSE AGGREGATES

FINE AGGREGATES

MINERAL FILLER

¾in.(19.0 mm) ½in.(12.5 mm) 5 ---- ----½in.(12.5 mm) 3/8in.(9.5mm) 32 ---- ----3/8in.(9.5mm) No.4(4.75mm) 37 ---- ----No.4(4.75mm) No.10(2.00mm) 22 7 ----No.10(2.00mm) No.40(0.475mm) 4 28 ----No.40(0.475mm) No.80(0.177mm) ---- 39 5No.80(0.177mm) No.200(0.75mm) ---- 24 30No.200(0.75mm) ----- ---- 2 65

Total 100 100 100


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For first trial, the amount of mineral filler is arbitrarily set at 8 percent. The total coarse aggregate in the mix must be from 50 to 65 percent, and this figure is set as 52 percent. The remaining 40 percent must be fine aggregate. Calculations made using the indicated proportions in determining the sieve analysis of the combined aggregates are as follows. A comparison of the figures in the last column of the table with the requirements of the specification will show that this combination of aggregates meets the stipulated requirements. This combination will therefore be judged satisfactory and no additional trials are made here.

Design Bitumen Content: When determining the design bitumen content for a particular blend or gradation of aggregates by Marshall Method, a series of test specimens is prepared for a range of different bitumen contents so that the test data curves show well-defined relationships.Bitumen content can be estimated from following sources Experience

Using filler-to-bitumen ratio guideline (ranges 06 to 1.2)

Computational Formula

P = 0.035a + 0.045b + K c + FWhereP = Approximate mix bitumen content, percentage by weight of total mixa = Percentage of mineral aggregate retained on sieve No.10 in whole no.b = Percentage of mineral aggregate passing sieve No.10 and retained on sieve No.200c = Percentage of mineral aggregate passing sieve No.200K = 0.15, 11-15% passing sieve No.200. = 0.18, 6-10% passing sieve No.200 =0.20, 5% passing sieve No.200F = 0 to 2%, based on the absorption of light and heavy aggregates. F = 0.7 incase no data is available.

Preparation Of Test Specimens:

Separate the aggregate in desired fractions by dry sieving.

The aggregates are first dried to a constant weight at 105 to 110°C.

Amount of each size fraction required to produce a batch that will give 63.5+1.27 mm high compacted specimen is weighed in a separate pan for each test specimen. It is about 1.2kg of dry aggregates.

Prepare at least three specimens for each combination of aggregates and bitumen.


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Dry the aggregates to the required mixing temperature.

Add heated aggregates in a mixing bowl and the required quantity of bitumen is added. Mixing is carried out until all aggregate particles are fully coated with bitumen.

Optimal viscosity of bitumen for compaction is between 2 Pa.s and 20 Pa.s. If viscosity is too low, the mix will be excessively mobile resulting in pushing of the material in front of the roller, high viscosities will significantly reduce the workability of the mix and little compaction will be achieved.

Depending upon design traffic category (light, medium and heavy), the compacted mix is expected to withstand 35, 50 and 75 blows respectively applied with compaction hammer to each end of the specimen.

After compaction, specimens are allowed to cool in air at room temperature until no deformation results on removal from the mould.

Apparatus: Sieves conforming to ASTM Standards

Moulds

Compaction Hammer

Flow meter

The Marshall Testing Machine, a compression testing machine.

Test Procedure: In Marshall Method, each compacted test specimen is subjected to following tests and analysis in the order listed. Bulk Specific Gravity Test

Stability and Flow Test

Density and Void Analysis

Bulk Specific Gravity Test is performed on freshly compacted specimens after they have cooled to room temperature.Then immerse the specimen in a water bath at 60°C for 30 to 40 minutes and perform Stability and Flow Tests.The Testing Machine will apply loads to test specimens through cylindrical segment testing heads at a constant rate of vertical strain of 51mm per minute. Loading is applied until the specimen failure occurs.


56


Marshall Stability Value: The force in Newton required producing failure of the test specimen. The applied testing load is determined from calibrated proving ring.

Flow Value:

The magnitude of deformation of the specimen at the point of failure. The point of failure is defined by the maximum load reading obtained. All fractions of aggregates are heated to a temperature of 250°F. Bitumen of specified

grade is heated to a temperature of 350°F. Bitumen should not be heated for more than an hour. The required quantity of aggregates and bitumen is mixed manually or electrically at a temperature of 200 to 300°F. After mixing place it in a compaction mould and give 75 blows to the sample on each side. The specimen is then immersed in water bath at a testing temperature of 60°C for 30 to 40 minutes. Then remove the specimen from water bath and place it on a base plate of Marshall Loading Machine. The proving ring and flow gauge are adjusted to zero reading. The base plate of machine moves upward at a rate of 2 inches per minute. The value of maximum load and dial gauges are recorded and machine is reversed. The elapsed time for the test after the removal of specimen is note.

Computations:

Percentage Air Voids, Va:

Va =100 X ( Gmm – Gmb ) GmmWhere, Va = air voids in compacted mixture as a percentage of total volume. Gmm = maximum specific gravity of a paving mixture, Gmb = Bulk specific gravity of a compacted mixture. Gmm = 100 W 1 / G 1 + W 2 / G 2 + W 3 / G 3 + W 4 / G 4Where, W 1 = %age weight of coarse aggregates,W 2 =%age weight of fine aggregates W 3 = %age weight of mineral aggregates W 4 = %age weight of bitumen, G1 = Specific Gravity of coarse aggregates G2 = Specific Gravity of fine aggregates G3 = Specific Gravity of mineral aggregates,G4 = Density of bitumen (g/cm3)


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Percentage Of Voids In Mineral Aggregates, Vma:

VMA = Vb + VaWhere, Va = %age of voids in aggregates, Vb = %age of voids in bitumen

Vb = Gmb X (W 4 / G 4)

Percentage Of Voids Filled With Bitumen, VFB:

VFB = ( Vb / VMA ) X 100

Observations And Calculations:


58Figure 26


Comments:


59


EXPERIMENT NO 12 Design of Flexible Pavement by Group Index Method

Introduction Group index is claimed to be an indirect measure of the thickness of sub-base required. The thickness of base and wearing surface, on the other hand, is varied according to the volume of commercial traffic expected. The higher the ‘Group Index’ of the sub-grade, the lower its strength and the greater thickness of sub-base required.Group index is based on classification tests of sub grade soil as explained below:Group Index = 0.2a + 0.005ac + 0.01bdWhere a= That portion of percentage of sub-grade soil passing No. 200 sieve greater than 35 and not exceeding 75, expressed as a positive whole number (0 to 40)b= That portion of percentage of sub-grade soil passing No. 200 sieve greater than 15 and not exceeding 55, expressed as a positive whole number (0 to 40)c= That portion of the numerical liquid limit greater than 40 and not exceeding 60, expressed as a positive whole number (0 to 20)d= That portion of the numerical plasticity index greater than 10 and not exceeding 30, expressed as a positive whole number (0 to 20)Design curves are based on the following assumptions with regard to compaction and drainageCompaction of the sub-grade to be not less than 95% of the maximum dry density obtained by modified AASHTO test (AASHTO T-l80 or ASTM D1557)Sub-grade to be sufficiently above the water-table to permit the proper compaction of the grade prior to placing the base or sub-base, and soil drainage or sufficient embankment height to be provided where necessary to keep the water-table at least 3 to 4 ft below the road face.

Related Theory

Sieve Analysis The shapes of the curves indicate the nature of the soil tested. On the basis of the shapes we can classify soils as:

1. Uniformly Graded Soil2. Poorly Graded Soil


60Figure 27(Sieve Test)


3. Well Graded Soil4. Gap Graded Soil

To determine whether a material is uniformly graded or well graded, Hazen proposed the following equation:

Cu=D60

D10

Cu > 4 for well graded gravelCu > 6 for well graded sandC < 4 for uniformly graded soil containing particles of the same sizeThere is another step in the procedure to determine the gradation of particles. This is based on the term called the coefficient of curvature which is expressed as

Cu=D30

2

D10×D60

The soil is said to be well graded if Cc lies between 1 and 3 for gravels and sands.

Atterberg Limits Atterberg, a Swedish scientist, considered the consistency of soils in 1911, and proposed a series of tests for defining the properties of cohesive soils. The Atterberg limits are a basic measure of the nature of a fine-grained soil. Depending on the water content of the soil, it may appear in four states:

Solid State semi-solid State plastic State liquid State

In each state the consistency and behavior of a soil is different and thus so are its engineering properties. Thus, the boundary between each state can be defined based on a change in the soil's behavior. The Atterberg limits can be used to distinguish between silt and clay, and it can distinguish between different types of silts and clays. These limits were created by Albert Atterberg, a Swedish chemist. They were later refined by Arthur Casagrande.

Shrinkage limit The shrinkage limit (SL) is the water content where further loss of moisture will not result in any more volume reduction. The test to determine the shrinkage limit is ASTM International D4943. The shrinkage limit is much less commonly used than the liquid limit and the plastic limit.

Plastic limit The plastic limit (PL) is the water content where soil starts to exhibit plastic behavior. A thread of soil is at its plastic limit when it is rolled to a diameter of 3 mm or


61Figure 28 (Plastic Limit)

http://en.wikipedia.org/wiki/ASTM_International

http://en.wikipedia.org/wiki/Arthur_Casagrande

http://en.wikipedia.org/wiki/Sweden

http://en.wikipedia.org/wiki/Albert_Atterberg

http://en.wikipedia.org/wiki/Albert_Atterberg

http://en.wikipedia.org/wiki/Clay

http://en.wikipedia.org/wiki/Silt

http://en.wikipedia.org/wiki/Water_content

http://en.wikipedia.org/wiki/Soil


begins to crumble. To improve consistency, a 3 mm diameter rod is often used to gauge the thickness of the thread when conducting the test.

Liquid limit The liquid limit (LL) is the water content where a soil changes from plastic to liquid behavior. The original liquid limit test of Atterberg's involved mixing a pat of clay in a little round-bottomed porcelain bowl of 10-12cm diameter. A groove was cut through the pat of clay with a spatula, and the bowl was then struck many times against the palm of one hand.

Casagrande subsequently standardized the apparatus and the procedures to make the measurement more repeatable. Soil is placed into the metal cup portion of the device and a groove is made down its center with a standardized tool. The cup is repeatedly dropped 10mm onto a hard rubber base during which the groove closes up gradually as a result of the impact. The number of blows for the groove to close for 13 mm (½ inch) is recorded. The moisture content at which it takes 25 drops of the cup to cause the groove to close is defined as the liquid limit.

Another method for measuring the liquid limit is the Cone Penetrometer test. It is based on the measurement of penetration into the soil of a standardized cone of specific mass. Despite the universal prevalence of the Casagrande method, the cone penetrometer is often considered to be a more consistent alternative because it minimizes the possibility of human variations when carrying out the test.

Plasticity index The plasticity index (PI) is a measure of the plasticity of a soil. The plasticity index is the size of the range of water contents where the soil exhibits plastic properties. The PI is the difference between the liquid limit and the plastic limit (PI = LL-PL). Soils with a high PI tend to be clay, those with a lower PI tend to be silt, and those with a PI of 0 tend to have little or no silt or clay.

Liquidity index The liquidity index (LI) is used for scaling the natural water content of a soil sample to the limits. It can be calculated as a ratio of difference between natural water content, plastic limit, and plasticity index: LI = (W-PL) / (LL-PL) where W is the natural water content.

AASHTO classifications of soils The AASHTO system classifies soils into seven primary groups, named A-1 through A-7, based on their relative expected quality for road embankments, sub-grades, sub-bases, and bases. Some of the groups are in turn divided into subgroups, such as A-1-a and A-1-b.


62

Figure 29 (Casagrande)

http://en.wikipedia.org/wiki/Cone_Penetrometer


Furthermore, a Group Index may be calculated to quantify a soil’s expected performance within a group. To determine a soil’s classification in the AASHTO system, one first determines the relative proportions of gravel, coarse sand, fine sand, and silt-clay.

AASHTO Classification Chart

General ClassificationGranular Materials (35% or less passing the 0.075 mm sieve)

Silt-Clay Materials (>35% passing the 0.075 mm sieve)

Group ClassificationA-1

A-3A-2

A-4 A-5 A-6A-7

A-1-a A-1-b A-2-4 A-2-5 A-2-6 A-2-7A-7-5 A-7-6

Sieve Analysis, % passing

2.00 mm (No. 10) 50 max … … … … … … … … … …

0.425 (No. 40) 30 max 50 max51 min

… … … … … … … …

0.075 (No. 200) 15 max 25 max10 max

35 max

35 max35 max

35 max

36 min

36 min

36 min

36 min

Characteristics of fraction passing 0.425 mm (No. 40)

Liquid Limit … …40 max

41 min40 max

41 min

40 max

41 min

40 max

41 min

Plasticity Index 6 max N.P.10 max

10 max11 min

11 min

10 max

10 max

11 min

11 min1

Usual types of significant constituent materials

stone fragments, gravel and sand

fine sand

silty or clayey gravel and sand

silty soils clayey soils

General rating as a subgrade

excellent to good fair to poor

Note: Plasticity index of A-7-5 subgroup is equal to or less than the LL - 30. Plasticity index of A-7-6 subgroup is greater than LL – 30 Unified Soil Classification System

Coarse Grained Soils

Primary G GravelS Sand

Secondary

W Well GradedP Poorly GradedM Non-PlasticC Plastic Fines

Fine Grained Soil Primary M Silt


63

http://en.wikipedia.org/wiki/AASHTO_Soil_Classification_System#fn_1

http://www.aboutcivil.com/atterberg-limits.html


C ClayO OrganicPt Peat

Secondary L Low PlasticH Highly Plastic

A-Line = PI – 0.73 ( LL – 20 )

Different States and Consistency of Soils with Atterberg Limits


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Curve Showing transition stages from the liquid to the solid stages

OBSERVATIONS AND CALCULATIONS Sieve AnalysisWeight of Sample =

Sieve No.Sieve Size (mm)

Weight of Soil Retained (gm)

%age weight Retained

Cumulative %age retained

%age Passing

4 4.7510 240 0.425100 0.15200 0.075Pan - - - -

Loss∈Weight after Sieving=W 1−W 2

W 1×100


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0.010.11101000

20

40

60

80

100

120Particle Size Distribution Curve

Particle Size (mm)

%ag

e Fi

ner b

y W

eigh

t

Silt & ClaySand

D60 = D30 = D10 = Cc = Cu =

From the curve and calculation of CU and CC it is clear that soil is ---------------

Results from Sieve Analysis % age passing Sieve # 200 Value of a 0Total weight retained after sieving

Value of b 0

Loss in weight after sieving

%age of Various Fractions Gravel Fine sandCoarse sand Silt & clayMedium sand - -

Liquid Limit (Soil fraction must be passing sieve # 40)

Sample No. 1 2 3Container No - - -


66

Grav


Weight of Empty Container = W1, gmW1 + Weight of Wet Soil = W2, gmW1 + Weight of dry Soil = W3, gmMoisture Content, W = (W2-W3)/(W3-W1) X 100%Number of Blows, N

Liquid Limit, LL by One Point Method =w (N23 )0.121

10 10023

24

25

26

27

28

f(x) = − 0.131315603807 x + 28.9891366257333

Liquid Limit Determination

No. of Blows (N)

Moi

stur

e Co

nten

t (%

)

Liquid Limit by Graphical Method =

Value of c =

Plastic Limit (Soil fraction must be passing sieve # 40)

Sample No. 1 2 3Container No - - -Weight of Empty Container = W1, gmW1 + Weight of Wet Soil = W2, gmW1 + Weight of dry Soil = W3, gmMoisture Content, W = (W2-W3)/(W3-W1) X 100%Average Plastic Limit, PL%

Plasticity Index, PI = LL – PL = 4.18 Value of d =

Group Index = AASHTO CLASSIFICATION = UNIFIED SOIL CLASSIFICATION = (Sand-Poorly graded with plastic fines)


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Design of Thickness of various Layers of Flexible pavement

With Sub-base

Traffic IntensityThickness of Surfacing(inch)

Thickness of Sub-base(inch)

Total Thickness of Surface, Base and Sub-base(inch)

Thickness of Base(inch)

Light 1 0 6 5Medium 2 0 9 7Heavy 3 0 12 9

Comments


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Figure 30 (Layers of Flexible Pavement)


EXPERIMENT NO 13 Design of flexible pavement by California bearing ratio method.

Code: ASTM-D-1883

Objectives: To determine the thickness of upper lying layers of subgrade using CBR method

Need and Scope: Soil strata strength is determined insitu and in lab as well. CBR method is employed to determine strength of soil. We need to design thickness to put in field.


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Apparatus: Modified Proctor moulds 10lb rammer CBR mould, rammer CBR testing machine

Procedure: 1. First of all, determine the OMC of the given soil by modified proctor test.2. Utilize modified dry density and optimum moisture content to fill the mould of CBR.3. Perform all the standard procedure for CBR to determine design CBR value.4. Correlate design CBR value with MR using following relation.

MR = 1500*CBR

5. From the Graph between MR and ESALS, determine the thickness of upper lying layers.

Definition of CBR

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 California Bearing Ratio Test (CBR Test) is a penetration test developed by California State Highway Department (U.S.A.) for evaluating the bearing capacity of subgrade soil for design of flexible pavement.

CBR Test Procedure 1:

Normally 3 specimens each of about 7 kg must be compacted so that their compacted densities range from 95% to 100% generally with 10, 30 and 65 blows.

Weigh of empty mould Add water to the first specimen (compact it in five layer by giving 10 blows per layer) After compaction, remove the collar and level the surface. Take sample for determination of moisture content. Weight of mould + compacted specimen. Place the mold in the soaking tank for four days (ignore this step in case of unsoaked

CBR. Take other samples and apply different blows and repeat the whole process. After four days, measure the swell reading and find %age swell. Remove the mould from the tank and allow water to drain. Then place the specimen under the penetration piston and place surcharge load of 10lb.


70

Figure 31(Mould)


Apply the load and note the penetration load values. Draw the graphs between the penetration (in) and penetration load (in) and find the

value of CBR. Draw the graph between the %age CBR and Dry Density, and find CBR at required

degree of compaction

Graph 1 (MR vs ESAL)

CBR Test Procedure 2:

Undisturbed specimen Attach the cutting edge to the mould and push it gently into the ground. Remove the soil from the outside of the mould which is pushed in . When the mould is full of soil, remove it from weighing the soil with the mould or by any field method near the spot. Determine the density Re-moulded specimen Prepare the re-moulded specimen at Proctor 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.


71


Dynamic Compaction Take about 4.5 to 5.5 kg of soil and mix thoroughly with the required water. Fix the extension collar and the base plate to the mould. Insert the spacer disc over the

base Place the filter paper on the top of the spacer disc. Compact the mix soil in the mould 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.

Remove the collar and trim off soil. Turn the mould upside down and remove the base plate and the displacer disc. Weigh the mould with compacted soil and determine the bulk density and dry density. Put filter paper on the top of the compacted soil (collar side) and clamp the perforated

base plate on to it.

Static compaction 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 mould from the expression.

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 mould = 2250 cm3 (as per the mould available in

laboratory) Take the weight W (calculated as above) of the mix soil and place it in the mould. Place a filter paper and the displacer disc on the top of soil. Keep the mould assembly in static loading frame and compact by pressing the displacer

disc till the level of disc reaches the top of the mould. Keep the load for some time and then release the load. Remove the displacer disc. The test may be conducted for both soaked as well as unsoaked conditions. If the sample is to be soaked, in both 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. 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.

Immerse the mould assembly and weights in a tank of water and soak it for 96 hours. Remove the mould from tank.

Note the consolidation of the specimen.

Procedure for Penetration Test Place the mould assembly with the surcharge weights on the penetration test machine.

(Fig.39).


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Seat 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.

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.

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.

Detach the mould from the loading equipment. Take about 20 to 50 g of soil from the top 3 cm layer and determine the moisture content.

Observation and Recording

For Dynamic Compaction Optimum water content (%) Weight of mould + compacted specimen g Weight of empty mould g Weight of compacted specimen g Volume of specimen cm3 Bulk density g/cc Dry density g/cc

For static compaction Dry density g/cc Moulding water content % Wet weight of the compacted soil, (W)g Period of soaking 96 hrs. (4days).

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 (Fig. 40). Find and record the correct load reading corresponding to each penetration. C.B.R. = PT/PS � 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 table I.


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Penetration Dial Load Dial Corrected Load

Readings Penetration (mm)proving ring

readingLoad (kg)

Comments:

Experiment No 15 Standard test method for use of dynamic cone penetrometer in

shallow pavement applications

Scope: This test method covers the measurement of penetration rate of cone penetrometer with an 8 kg hammer through undisturbed soil or compacted materials. Penetration rate may be related to in-situ strength such as an estimated in-situ CBR.

Significance and Use: Determine in-situ strength of undisturbed soil and compacted materials. Dynamic cone penetrometer is held vertically and therefore is typically used in

horizontal construction applications such as pavements and floor slabs. Can be used to assess material properties down to a depth of 1000 mm .


74


Apparatus: A 16 mm diameter steel drive rod with a replaceable point or disposable cone tip.(60

degrees and diameter of 20 mm at the base) 8 kg hammer with a fixed dropped height of 575 mm. Coupler assembly and Handle


75


Procedure: Before Beginning the test, Check the DCP for fatigue damaged parts in particular the coupler and handle and excessive wear of drive rod and replaceable point tip. The basic operation is that operator holds the device in a vertical or plumb position and lifts and releases the hammer from standard drop height. The recorder measures and records the total penetration for a given number of blows or the penetration per blow.

Testing a Surface Layer: The DCP is held vertically and tip seated such that the top of widest part of tip is flush with the surface of material to be tested and initial reading is obtained from graduated drive rod or a separate vertical scale. The distance is measured to nearest 1 mm some sliding reference attachments allow the measuring rod to be marked at zero when tip is at zero point.

Testing Below a Bound Layer: A Rotary hammer drill is used to provide excess whole to the layer to be tested. Wet coring is required so that fluid be removed immediately and DCP test be performed as soon as possible no longer than 10 minutes after coring. Then DCP may be performed.

Testing Sequence:

Dropping the Hammer - The DCP device is held vertically and operator raises the hammer until it makes only light contact with handle then it is allowed to free fall and impact the annual coupler assembly. The number of blows and corresponding penetrations are recorded.

Depth of Penetration - For typical highway application, a penetration less than 900 mm is used.

Refusal: - Large aggregates or rocks strata can stop further penetration. If after five blows the penetration is not more than 2 mm or the handle has deflected more than 75


76


mm from vertical position, the test shall be stopped. Select new test location atleast 300 mm far from the previous location.

Extraction - At completion, use extraction jack for replaceable point tip DCP and for disposable cone DCP, hammer is striked upward into the handle to extract the DCP.

Data Recording:

Calculations and Interpretation of Results: CBR= 292/DCP1.12 (DCP in mm/blow)CBR=292/ (DCP*25.4)1.12 (DCP in inch/blow)

Comments


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highway & traffic engineering lab...

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