project hardcopy

MAJOR PROJECT IN CIVIL ENGINEERING 8 TH SEM.

CONTENTS

PAGE NO.

1. INTRODUCTION 3

2.1 Planning 3

2.2 Alignment 3

2.3 Engineering Survey`s 4

3. GEOMETRIC DESIGN FEATURE OF VILLAGE ROAD 8

3.1 Importance of Geometric Design 8

3.2 Terrain classification 9

3.3 Design Speed 9

3.4 Roadway width 10

3.5 Shoulder width 11

3.6 Side Slope 11

3.7 Camber 12

3.8 Vertical curve , Summit curve, Valley curve 12

4. DESIGN FACTOR`S OF FLEXIBLE PAVEMENT 13

4.1 Pavement Component 13

4.2 Types of pavements 13

4.3 Design wheel load 16

4.4 Design Traffic Volume 18

5.0 LABORATORY WORK ON SUBGRADE 18

6. METHODOLOGY 19

(PAVEMENT DESIGN BY C.B.R. METHOD) 30

7. TESTING OF PAVEMENT MATERIALS 35

8. CONCLUSION 47

9. REFERENCES 48

1FLEXIBLE PAVEMENT DESIGN ON BLACK COTTON SOIL


INTRODUCTI0N

The term highway is used to mean a public road, and a road indicates a way made

for travelling between places by automobiles , pedestrains , cyclists, animals , etc. Thus

highway engineering means the art of designing, constructing and maintaining public roads.

It is significant to note that the networks of highways existed in all parts of the world

for the flow of people and good the initial carrier on a highway was man himself followed by

the camel, donkey, horse and after the invention of wheel, the cart and many other wheeled

vehicles.

The technique of highway engineering is thus known to man, hundred and even

thousands of years before our time. The problem of highway engineering such as

constructing , maintaining , managing , financing, controlling the traffic,etc. were also

faced by our predecessors and they solved these problems in their own way to satisfy

their requirements.

There has been considerable explosion of vehicular traffic on highways in modern

times and at the same time , the automobile industry has also undergone wide expansion.

There has also been considerable improvement in highway construction technology.



PLANNING , ALIGNMENT AND SURVEY`S

1 PLANNING :-

In order to prepare a scientific master plan for rural roads, it is necessary to build

a comprehensive database for all habitations and the existing network of all types of

roads and tracks, preferably in the invironment. The first step in preparation of master

plan would be collect all the information available at district, block and habitation level

from secondary sources. The next step is to collect the detailed information on each

habitation and road link through field surveys. Various data items required for developing

the village road link through field surveys. Various data items required for developing the

village road plan can be broadly identified under three categories

1.Habitation level data.

2. Road inventory data.

3. Map data.

2. ALIGNMENT :-

considerations The position or the layout of the centre line of the highway on the

ground is called the Valignment. The horizontal alignment includes the straight path, the

horizontal deviations and curves. Changes in gradient and vertical curves are covered under

vertical alignment of roads.

A new road should be aligned very carefully as improper alignment would result in

one or more of the following disadvantages :

(a) increase in construction cost

(b) increase in maintenance cost

(c) increase in vehicle operation cost

(d) increase in accident rate.


MAJOR PROJECT IN CIVIL ENGINEERING 8 TH SEM. Once the road is aligned and constructed, it is not easy to change the alignment due

to increase in cost of adjoining land and construction of costly structures by the road side.

Hence the importance of careful while finalizing the alignment of a new road need not be

over emphasised.

Factors Controlling Alignment :-

For an alignment to be shortest, it should be straight between the two terminal stations. This is not

always possible due to various practical difficulties such as intermediate obstructions and

topography. A shortest route may have very steep gradients and hence not easy for vehicle

operation. Similarly, there may be construction and maintenance problems along a route which may

otherwise be short and easy. Roads are often deviated from the shortest route in order to cater for

intermediate places of importance or obligatory points.

A road which is economical in the initial construction cost, need not necessarily be the most

economical in maintenance or in vehicle operation cost. It may also happen that the shortest and

easiest route for vehicle operation may work out to be the costliest of the different alternatives from

construction view point. Thus it may be seen that an alignment can seldom fulfill all the requirements

simultaneously; hence a judicial choice is made considering all the factors.

The various factors which control the highway alignment in general may be

listed as :

(a) Obligatory points

(b) Traffic

(c) Geometric design

(d) Economics

2.3 SURVEYS :-

ENGINEERING SURVEYS FOR HIGHWAY LOCATIONS

A highway alignment is finalised in highway project, the engineering surveys are be

carried out. The surveys may be completed in four stages. The first three stages consider

Before all possible alternate alignments keeping in view the various requirements of highway


MAJOR PROJECT IN CIVIL ENGINEERING 8 TH SEM. alignment as discussed in Art. 3.1.2. The fourth stage is meant for the detailed survey of the

selected alignment.

The stages of the engineering surveys are

(a) Map study

(b) Reconnaissance

(c) Preliminary surveys

(d) Final location and detailed surveys.

Map Study:-

If the topographic map of the area is available, it is possible to suggest the likely

routes of the road. In India topographic maps are available from the Survey of India, with 15

or 30 meter contour intervals; The main features like rivers, hills valleys etc. are also shown

on these maps. By careful study of such maps, it is possible to have an idea of several

possible alternate routes so that further details of these may be studied later at the site. The

probable alignment can be located on the map from the following details available on the

map.

(a) Alignment avoiding valleys, ponds or lakes

(b) When the road has to cross a row of hills, possibility of crossing through a mountain pass

(c) Approximate location of bridge site for crossing rivers, avoiding bend of the river, if any,

(d) When a road is to be connected between two stations, one of the top and the other on

the foot of the hill, then alternate routes can be suggested keeping in view the

permissible gradient; say the ruling gradient.

Reconnaissance :-

The second stage of surveys for highway location is the reconnaissance to examine

the general character of the area for deciding the most feasible routes for detailed studies. A

field survey party may inspect a fairly broad stretch of land along the proposed alternative

routes of the map in the field. Only very simple instrument like abney level, tangent

clinometer, barometer etc. are used by the reconnaissance party to collect additional details 5

FLEXIBLE PAVEMENT DESIGN ON BLACK COTTON SOIL

MAJOR PROJECT IN CIVIL ENGINEERING 8 TH SEM. rapidly (not accurately). All relevant details not available in the map are collected and noted

down. Some of the details to be collected during reconnaissance are given below:

(i) Valleys, ponds, lakes, marshy land, ridge, hills, permanent structures and other

obstructions along the route which are not available in the map.

(ii) Approximate values of gradient, length of gradients and radius of curves of alternate

alignments.

(iii) Number and type of cross drainage structures, maximum flood level and natural

ground water level along the probable routes.

(iv) Soil type along the routes from field identification tests and observation of geological

features.

(v) Sources of construction materials, water and location of stone quarries.

(vi) When the road passes through hilly or mountainous terrain, additional data

regarding the geological formation, type of rocks, dip of strata, seepage flow etc.

may be observed so as to decide the stable and unstable sides of the hill for highway

alignment.

A rapid reconnaissance of the area especially when it is vast and the terrain is

difficult, may be done by an aerial survey.

Preliminary Survey:-

(i) To survey the various alternate alignments proposed after the reconnaissance and to

collect all the necessary physical information and details of topography, drainage and

soil.

(ii) To compare the different proposals in view of the requirements of a good alignment.

(iii) To estimate quantity of earth work materials and other construction aspects and to

workout the cost of alternate proposals.

(iv) To finalise the best alignment from all considerations.

Final Location and Detailed Survey: -

The alignment finalised at the design office after the preliminary survey is to be first

located on the field by establishing the centre line. Next detailed survey should be carried out


MAJOR PROJECT IN CIVIL ENGINEERING 8 TH SEM. for collecting the information necessary for the preparation of plans and construction details

for the highway project.

Location

The centre line of the road finalised in the drawings is to be translated on the ground

during the location survey. This is done using a transit theodolite and by staking of the centre

line. The location of the centre line should follow, as closely as practicable, the alignment

finalised after the preliminary surveys. Major and minor control points are established on the

ground and centre pegs are driven, checking the geometric design requirements. However

modifications in the final location may be made in the field, if found essential. The centre line

stakes are driven at suitable intervals, say at 50 metre intervals in plain and rolling terrains

and at 20 metre in hilly terrain.

Detailed survey

Temporary bench marks are fixed at intervals of about 250 metre and at all drainage

and under pass structures. Levels along the final centre line should be taken at all staked

points. Levelling work is of great importance as the vertical alignment, earth work

calculations and drainage details are to be worked out from the level notes. The cross

section levels are taken upto the desired width, at intervals of 50 to 100 metre in plain

terrain, 50 to 75 metre in rolling terrain, 50 metre in built-up areas and 20 metre in hilly

terrain. The cross sections may be taken at closer intervals at horizontal curves and where

there is abrupt change in cross slopes. All river crossing, valleys etc. should be surveyed in

detail upto considerably distances on either side.



GEOMETRIC DESIGN FEATURE`S OF VILLAGE ROAD

3.1 Importance of Geometric Design:-

The geometric design of a highway deals with the dimensions and layout of visible

Matures of the highway such as alignment, sight distances and intersections.

The geometries of highway should be designed to provide optimum efficiency in

traffic operations with maximum safety at reasonable cost. The designer may be exposed to

either planning of new highway net work or improvement of existing highways to meet the

requirements of the existing and the anticipated traffic.

It is possible to design and construct the pavement of a road in stages; but it is very

expensive and rather difficult to improve the geometric elements of a road in stages at a

later date. Therefore it is important to plan and design the geometric features of the road

during the initial alignment itself taking into consideration the future growth of traffic flow

and possibility of the road being upgraded to a higher category or to a higher design speed

standard at a later stage.

Geometric design of highways deals with following elements :

(i) Cross section elements

(ii) Sight distance considerations

(iii) Horizontal alignment details

(iv) Vertical alignment details

(v) Intersection elements

Under cross section elements, the considerations for the width of pavement,

formation and land, the surface characteristics and cross slope of pavement are included.

The sight distance or clear distance visible ahead of a driver at horizontal and vertical curves

and at intersections govern the safe movements of vehicles.

Classification of Rural Roads


MAJOR PROJECT IN CIVIL ENGINEERING 8 TH SEM. The rural roads in India are commonly referred to:

(i) Other District Roads (ODR)

(ii) Village Roads (VR)

3.2 Terrain Classification:-

The general slope of the country classifies the terrain across the area. The terrain is

an important parameter governing the geometric standards and the criteria given in Table

2.1 should be followed. While classifying a terrain short isolated stretches of varying terrain

should not be taken into

consideration.

Table 1 - Terrain Classification

Terrain Classification Cross slope of the Country

Plain 0-10 per cent More than 1 in 10

Rolling 10-25 per cent 1 in 10 to 1 in 4

Mountainous 25-60 per cent 1 in 4 to 1 in 1.67

Steep Greater than 60 per cent Less than 1 in 1.67

3.3 Design Speed :-

Design speed is a basic criterion for determining all geometric features of horizontal

and vertical alignments. The design speeds for the rural roads should be taken as given in

Table.



DESIGN SPEED

Road Classificatio

n

Design Speed (km/h)

Plain Terrain Rolling Terrain Mountainous Terrain

Steep Terrain

Ruling Min. Ruling Min. Ruling Min. Ruling

Min.

Rural Roads (ODR and VR)

50 40 40 35 5 20 25 20

Normally ruling design speed should be the guiding criterion for the purpose of

geometric design. Minimum design speed may, however, be adopted where site condition

and cost does not permit a design based on "Ruling Design Speed".

3.4 Roadway width :-

Roadway width inclusive of parapet, side drains for rural roads for different terrain

shall be as given in Table.

Recommended Roadway Width

Terrain Classification Roadway Width (m)

Plain and Rolling 7.5

Mountainous and Steep 6-0



RECOMMENDED CARRIAGEWAY WIDTH

Road Classification Carriageway Width (m)

Rural Roads (ODR and VR) 3.75

3.4.1 Shoulder width :

The width of shoulder for rural roads in different terrain can be directly obtained

using above Tables. Shoulder width will be one half the difference between the roadway

width and carriageway width.

3.5Side-slopes : -

Side slope for rural road where embankment height less than 3.0 m is given in Table.

SIDE SLOPE FOR VILLAGE ROADS

Condition Slope (H:V)

Embankment in silty/sandy/gravelly soil 2:1

Embankment in clay or clayey silt or

inundated

21/21 to 3:1

Cuttingm silty/sandy/gravelly soil 1:1 to 1/2:1

Cutting in disintegrated rock or

conglomerate

1/:1 to 1/4:1

Cutting in soft rock like shale 1/4:1 to 1/8:1

Cutting in medium rock like sandstone,

phyllite

1/12 to 1/16:1

Cutting in hard rock like quartzite, granite Near vertical



3.6 Camber :-

The camber on straight section of road should be as recommended in Table.

Surface Type Camber (Percent)

Low Rainfall (Annual Rainfall > 1000 mm)

High Rainfall (Annual Rainfall M < 1000 mm)

Earth road 4.0 5.0

WBM and gravel road 3.5 4.0

Thin bituminous pavement 3.0 3.5

Rigid pavement 2.0 2.5

3.7Vertical curve:-

Vertical curves are introduced for smooth transition at grade changes. Both summit curves

and valley curves should be designed as parabola. The length of the vertical curve is

controlled by sight distance requirements, but curves with greater length are aesthetically

better. Curves should be provided at all grade changes exceeding those given in table. For

satisfactory appearance, the length should be as given in the table.

MINIMUM LENGTH OF VERTICAL CURVE

Design Speed Km/h Maximum Grade Change (%) Not Requiring a Vertical Curve

Minimum Length of Vertical Curve (meter)

Up to 35 1.5 15

40 1.2 20

50 1.0 30



3.8 Summit Curve : -

The length of summit curve is governed by the choice of sight distance according to

the operating condition of the road.

DESI

GN FACTOR`S OF FLEXIBLE PAVEMENT

Pavement:-

The surface of the roadway should be stable and non-yielding, to allow the heavy

wheel loads of road traffic to move with least possible rolling resistance. The road surface

should also be even along the longitudinal profile to enable the fast vehicles to move safely

and comfortably at the design speed.

Thus a pavement consisting of a few layers of pavement materials is constructed over

a prepared soil subgrade to serve as carriageway.

4.1 Type of pavement structure –:

Based on the structural behaviour, pavements are generally classified into two categories:

(i) Flexible pavements

(ii) Rigid pavements



4.1.1 Rigid pavement:-

Rigid pavements are those which possess note worthy flexural strength or flexural rigidity.

The stresses are not transferred from grain to grain to the lower layers as in the ease of

flexible pavement layers. The rigid pavements are made of Portland cement concrete-either

plain, reinforced or prestressed concrete.

The rigid pavement does not get deformed to the shape of the lower surface as it can

bridge the minor variations of lower layer

The cement concrete pavement slab can very well serve as a wearing surface as well

an effective base course.

the cement concrete slab can also be laid directly over the soil sub grade.The rigid

Though pavements are usually designed and the stresses are analyzed using the elastic

theory, assuming the pavement as an elastic plate resting over elastic or a viscous

foundation.


MAJOR PROJECT IN CIVIL ENGINEERING 8 TH SEM. 4.1.2 Flexible pavements:-

Flexible pavements are those, which on the whole have low or negligible flexural strength

and are rather flexible in their structural action under the loads. The flexible pavement layers

reflect the deformation of the lower layers on-to the surface of the layer. Thus if the lower

layer of the payment or soil sub grade is undulated, the flexible pavement surface also gets

undulated. Atypical flexible pavement consists of four components: (i) soil sub grade (ii) sub-

base course (iii) base course and (iv) surface course.

The flexible pavement layers transmit the vertical or compressive stresses to the

lower layers by grain to grain transfer through the points of contact in the granular

structure. A well compacted granular structure consisting of strong graded aggregate

(interlocked aggregate structure with or without binder materials) can transfer the

compressive stresses through a wider area and thus forms a good flexible pavement layer.

The flexible pavement may be constructed in a number of layer and the top layer, in

addition to the wear and tear due to the traffic.

1. Soil sub grade 2. Sub base course 3. Base course4. Surfacing

1.soil subgrade: -

This is the natural or prepared soil on which the road has to be formed . it

should be stable and strong to carry safely the traffic load and weight of roadway

construction The common strength tests for the evaluation of soil sub grade are

1. California bearing ratio test

2 .California resistance value test

3 .Traixial compression test and

4 . Plate bearing test.



2.sub base course:-

The sub base course functions as a support to the road surface and its

foundation .the life of road depend on primarily on stable and dry subgrade.its level may be

same as or above or below the natural ground level .the support given to the road structure

by the subgrade is an important factor and hence , considerable attention should be paid to

the proper preparation of subgrade before the road structure is laid on it

3. Base course:-

T he base course may consist of two layers3. Base course:- the base

course may consist of two layers, the bottom layer being known as sub-base or soling.the

subbase should be stable and it should be capable to resist its deterioration under traffic

loads to a great extent.

4. Surfacing:-

The top most layer on which the traffic directly travels is known as road surfacing or

wearing layer or wearing course. The main function of road surfacing is to provide a

smooth and stable running surfacing which is suitable for the type and intensity of

traffic anticipated on the road .the surfacing should be impervious and should

protect the base and the subgrade from the action of weather and rain water the

desirable qualities of surfacing are durability, stability, non slipperiness, economical

and dustless.

4.2 Design Wheel Load :-

The wheel load configurations are important to know the way in which the loads of a

given vehicle are applied on the pavement surface. Typical wheel load configuration of a

tractor trailer unit of a heavy duty vehicle. For highways the maximum legal axle load as

specified by India Roads congress is 8170 kg with a maximum equivalent single wheel load

4085kg. Total load influences the thickness requirements of pavements. Tyre pressure

influences the quality of surface (wearing) course.



Flexible pavement design methods :-

Out of the various flexible pavement design methods available the following are

discussed here.

1. Group index method

2. California Bearing Ration method

3. California R value or stabilometer method

4. Triaxial test method

5. Mcleod method

6. Burmister method

7. In 1928 California Division of Highways in the U.S.A. developed CBR method

for pavement design. The majority of design curves developed later are based

on the original curves proposed by O.J. porter 3.

One of the Chief advantages of CBR method is the simplicity of the test procedure.

Studies carried out by U.S. Corps of Engineers have shown that there exists a

relationship between pavement thickness, wheel load tyre pressure and C.B.R. Values

within a range of 10 to 12 percent. Therefore it is possible to extend the C.B.R. design

curves for various loading conditions, using the expression

4.3Pavement Thickness DETERMINATION:-

In order to design a pavement – Thus the total thickness of flexible pavement needed to

cover the sub grade of the known CBR value is obtained. In case there is a material superior

than the soil sub grade, such that it may be sued as sub-base course then the thickness of

construction over this material could be obtained from the design chart knowing the CBR

value of the sub-base. Thickness of the sub-base course is the total thickness minus the

thickness over the sub-case. Thus CBR method of flexible pavement design is based on

strength parameter of sub grade soil and subsequent pavement material.



4.4 Design life

Design life is usually defined as the number of design life the first major reconstruction is

anticipated. For un surfaced rood’s aggregates are displaced on either side of the wheel path

and frequent balding is necessary to main fain a good riding surface. For unsealed or

unsurfaced road aggregate’s are after lost must be replenished periodically to maintain the

ride. Ability It is necessary that sufficient thickness is provided to prevent rutting failure.

During the design life of 10 years. The thin bituminous surfacing that is commonly provided

on the low volume roads has a life of about 5 years.

4.5 TRAFFIC DESIGN:-

Traffic volume studies are conducted to determine the number, movements, and

classifications of road way vehicles at a given location. These data can help identify critical

flow time periods determine the influence of large vehicles or pedestrians on vehicular traffic

flow, or document traffic volume trends. The length of the sampling period depends on the

type of count being taken and the intended use of the data

Traffic volume:-

Two methods are available for conducting traffic volume counts:

(1) manual

(2) Automatic.

LABORATORY WORK ON SUBGRADE

Black cotton soils –

A large part of central India and a portion of south India is covered with

black cotton soils. These soils are residual deposits formed from basalt or trap rooks. The

sails are quite suitable for growing cotton.



Property

1. Black cotton soils are clays of high plasticity.

2. They certain essentially the clay mineral montmorillonite.

3. The soils have high shrinkage and swelling characteristics .

4. The shearing strength of the soils is extremely low.

5. The sails are highly compressible and have very low bearing capacity.

6. It is extremely difficult to work with such soils.

METHODOLOGY

The two type work was carried out shown below-

A. Fieldwork

B. Laboratory Work

After obtaining soil samples, the tests which were performed on soil sample are listed below

1. Natural Moisture Content

2. Specific Gravity

3. Sieve Analysis

4. Liquid Limit

5. Plastic Limit

6. Light Compaction

7. Direct Shear Test

8. C.B.R. Test19



FIELD WORK -:

The soil sampling was carried out in the field.

Soil Sampling - Two types of samples which are to be taken from medical college site by

means of Auger, soil samplers etc. areThe sample obtained by column of soil isolated in the

pit. The soil was carefully removed around the soil column and it was then properly trimmed.

An open ended box was then placed over the soil column. The spaces between the columns

were filled with paraffin. A spade or a plate with sharp edges was inserted below. The box

and the sample were cutted from its base. The box filled with soil sample was then removed.

It was turned over and the soil surface in the box is trimmed, and depression is filled with

paraffin.

This sample used for determining the engineering properties of the soil; such as shear

strength and consolidation. Some index properties such as shrinkage limit also be determine.



Laboratory Work

Laboratory work was carried out on the given samples of soil obtained from medical college site

1. NATURAL MOISTURE CONTENT : -

In almost all soil tests natural moisture content of the soil is to be determined. The

knowledge of the natural moisture content is essential in all studies of soil mechanics. To site

a few natural moisture content is used in determining g the bearing capacity and settlement

the natural moisture will give an idea of the state of soil in field.

The natural water content also called the natural moisture content is the ratio of the

weight of the water to the weight of the solid in a given mass of soil. This ratio is usually

expressed as percentage.

Size of particles more than 90% Minimum quantity of soil specimen

passing to be taken for testing (g)

425-micron IS sieve 25

2 mm IS sieve 50

4.75 mm IS sieve 200

9.5 mm IS sieve 300

19 mm IS sieve 500

37.5 mm IS sieve 1000

1. Keep the container in the oven with lid removed and maintain the temperature of

the oven between 105 °C to 110°C, for about 16 to 24 hours.

2. Take out the container, replace the lid and cool it in the desiccator. Find the mass

M3 of the container with lid and dried soil sample The natural moisture content was

determined with the help of distrubed Sample obtained from different depths. The values of

natural moisture content shown below-:

S.No. Depth in meter Natural Moisture

content (%)21


MAJOR PROJECT IN CIVIL ENGINEERING 8 TH SEM. 1 1-00-1-35 17.8

2 2.5-2.85 19.4

2. SPECIFIC GRAVITY BY PYCNOMETER

Test Procedure

1. Clean the pycnometer and dry it. Find the mass (Mi) of the pycnometer, brass cap

and washer, accurate to 1 g.

2. Take about 200 to 400 g of oven-dried soil and put it in the pycnometer. Find the

mass at the pycnometer plus soil etc. (M1).

3. Fill the pycnometer to half its height with distilled water and mix it thoroughly with

g rod. Add more water and stu it. Replace the screw top and ffl\ the pycnometer flush with

ht> the conical cap. Dry the pycnometer from outside, and find the mass (M3).

4. Empty the pycnometer ; clean it thoroughly and fill it with distilled water to the

hole of conical cap and find the mass (M1).

5. Repeat steps 2 to 4 for two more determinations of specific gravity.

Calculations. The Specific Gravity is calculated from Eq. 3.3 :

The specific gravity of soil grains (or solids) usually Called soil is ratio of the weight in air of

the given volume of dry soil solids at a stated temperature to the weight on air of an equal

volume of distilled water at a temperature. Specific gravity was determined with the help of

pycnometer in the laboratory. The disturbed sample was taken. From the site and subject to

pycnometer test and specific gravity was determined. The specific gravity was determined

the specific gravity of soil sample of different depths shown below

RESULT

S.No. Depth in meter Specific Gravity

1 1-00-1-35 2-66


MAJOR PROJECT IN CIVIL ENGINEERING 8 TH SEM. 2 2.5-2.85 2-67

3- Sieve analysis:-

Sieve analysis or mechanical analysis is carried out for one classification of soil, for this

purpose the test was conduct on the disturbed sample of soil, which was obtained from the

medical college site kept for sieve analysis.

Water was used for sieve analysis because the soil was and silt particles dislodged very easily

around the sand particles when the water with hexameter phosphate is used to clean the soil

The sieve sizes were taken for the sieve analysis

IS sieve – 20 , 10mm, 4.75mm, 2mm, 1mm, 600 micron, 425 micron, 300 micron, 75 micron.

S.no IS sieve sizes no. % finer N

1 20 mm 100

2 10 mm 100

3 4.75 mm 100

4 2 mm 99.7

5 1 mm 99.5

6 600 mica. 95.3

7 425 mica 98.9

8 300 mica. 98.7

9. 125 mica. 96.9

10. 75 mica 93.5



LIQUID LIMIT OF SOIL

Liquid limit is determined in the laboratory with the help of standard liquid limit

apparatus designed by casagrande. Liquid limit is the water content corresponding to the

arbitrary limit between liquid and plastic state of consistency of a soil. It is defined as the

minimum water content at which a part of soil cut by a groove of standard dimension will

flow together for a distance of 12mm under an impact of 25 blows in the device.

Test Procedure

1. By means of the gauge on the handle of the grooving tool and the adjustment

plate, adjust

The height through which the cup is lifted and dropped so that the point on the cup which

comes in contact with the base falls through exactly one centimetre when the handle is

rotated by one revolution.

When the adjustment is complete, secure the adjustment plate by tightening its screws.

2. Take about 120 g of the specimen, passing through the 425 micron sieve, and mix it

thoroughly with distilled water in the evaporating dish or on the marble plate so that

uniform paste is formed Leave the soil for sufficient time so that water may permeate

throughout the soil mass. In the case of fat clays, this maturing time may be upto 24 hours.

For an average soil, thorough mixing for

about15 to 30 minutes may be sufficient. The amount of water to be added depends on the

type of soil and is a matter of experience.

3. Take a portion of the paste with the spatula and place it in the centre of the cup so that

it is almost half filled. Level off the top of the wet soil symmetrically with the spatula, so that

it is parallel to the rubber base and the maximum depth of the soil is 1 cm.

4. With the help of grooving tool 'a', the paste in the cup is divided along the cup diameter

5. Turn the handle of the apparatus at the rate of 2 revolutions per seconds, until the two

parts of the soil come in contact with the bottom of the groove along a distance of 10 mm.

Record the number of blows required to cause the groove close for approximate length of 10


MAJOR PROJECT IN CIVIL ENGINEERING 8 TH SEM. 6.Collect a representative slice of soil by moving the spatula widthwise from one edge to the

other edge of the soil cake at right angles to the groove.

Plastic Limit

Plastic limit is defined as the minimum water content at which a soil will just begin to crumble when rolled into a thread approximately 3 mm in diameter.

Undisturbed soil specimen was taken from medical college site allowed to pass through 4.25 micron sieve. Passed soil was mixed with water thoroughly. Until the soil mass becomes plastic enough to be easily mould with fingers. After some time ball was made of soil mass and then rolled between the finger and a glass plate till the soil just crumble. The crumble threads were kept for water content determination. We have repeated the test twice with fresh sample of soil. Plastic limit was taken as the average of three water content.

Test was organized with the soil sample at different depth the plastic limit obtained from

different depth were shown in table.

1. Take about 20 g of air dried soil from the thoroughly mixed portion of the material

passing420 micron IS sieve. Mix it on the marble plate with sufficient distilled water to

make it plastic enoughto be shaped into a ball. Leave the plastic soil mass for some time to

mature. In some fat clays, theplastic soil mass may be left to stand for 24 hours to allow

water to permeate throughout the soil mass.

2. Take about 8 g of the plastic soil, make a ball of it, and roll it on the marble (or

glass)plate with the hand with just sufficient pressure to roll the mass into a thread of

uniform diameter throughout its length. When the diameter of the thread has decreased to

3 mm, the specimen is kneaded together and rolled out again. Continue the process until

thread just crumbles at 3 mm diameter.

3. Collect the crumbled soil thread in the airtight container and keep it for water

content determination The test is repeated twice more. Thus three readings are obtained

for the determination.

4. Also, determine the natural water content of the soil sample obtained from the

field.



Light compaction

Purpose

Soil placed as engineering fill (embankments, foundation pads, road bases) must be

compacted to the selected density and water content to ensure the desired performance and

engineering properties such as shear strength, compressibility, or permeability. Also,

foundation soils are often compacted to improve their engineering properties. Laboratory

compaction tests provide the basis for determining the percent compaction and water content

needed in the field, and for controlling construction to assure that the target values are

achieved. In a geotechnical laboratory you would prepare at least four (preferably five)

specimens with water contents bracketing the estimated optimum water content. A specimen

having a water content close to optimum would be prepared first by trial additions of water

and mixing and then water contents for the rest of the specimens would be selected to provide

at least two specimens wet and two specimens dry of optimum, and water contents varying by

about 2%, but no more than 4%. In this laboratory exercise each group in yours ection will

compact one of the specimens at a specific water content, as directed by the laboratory

instructor, and the results from all the groups will be combined later. The data, when plotted,

represents a curvilinear relationship known as the compaction curve. The values of optimum

water content and standard maximum dry unit weight are determined from the compaction

curve. These test methods apply only to soils (materials) that have 20% or less by mass of

particles retained on the No.4 (4.75 mm) sieve.

Procedure

Specimen preparation

1. Obtain from your laboratory instructor a sample of the soil to be tested. You will need

approximately2 kg.

2. Without previously drying the sample, pass it through a No. 4 (4.7 mm) sieve. Determine

the water

content of the processed soil. See chapter 2 for the procedure.

3. Double check the target water content for your specimen with the laboratory instructor.


MAJOR PROJECT IN CIVIL ENGINEERING 8 TH SEM. 4. Calculate how much water should be added or subtracted from your sample to obtain the

desired water content. Remember to account for the moisture already present in the sample

and use the exact value for the mass of the soil, not the approximate number.

Direct shear test

1.Preparation of specimen

1.The undisturbed specimen is prepared by pushing a cutting ring of size 10 cm in diameter

and 2cm high, in the undisturbed soil sample obtained from field. The square specimen of

size 6 cm× 6 cm is then cut from the circular specimen so obtained.

2.In order to obtain remoulded specimen of cohesive soil, the soil may be compacted to the

required density and water content, in a separate bigger mould . The sample is then

extracted and trimmed tire required size. Alternatively, the soil may be compacted at the

required density and water content directly into the shear box after fixing two halves of the

shear box together by means, of the fixing screws.

3. Non-cohesive soils may be tamped in the shear box itself with the base plate and grid

plate or porous stone as required in place at the bottom of the box.

4.In all the three cases mentioned above, water content and dry density of the soil

compacted in the shear box should be determined,

(ii) Undrained test 1. The shear box with the specimen plain grid plate over the base plate at the bottom of

the specimen plain grid plate over the top of the specimen, should be fitted into positio .The

serrations of the grid plates should be placed at right angles to the direction of shear. As

the porous stones are not used in the undrained tests, plain plates of equal thickness

should be placed, one at the bottom and other at the top of the two grids, so as to

maintain the shear plane in the sample in the middle of its thickness. Place the loading pad

on the top of the plain grid plate. Both the parts of the box should be tightened together

by the fixing screws.

Put water inside the water jacket so that the sample does not get dried during the test.

2.Mount the shear box assembly cn the load frame (or shearing machine). Set the lower

part of the box to bear against the load jack and the upper part of the box to bear against

the proving ring set the dial of the proving ring to zero.


MAJOR PROJECT IN CIVIL ENGINEERING 8 TH SEM. 3.Put the loading yoke on the top of the loading pad, and adjust the dial gauge to zero to

measure the vertical displacement in the soil sample. Put proper normal weight on the

hanger of the loading yoke, so that this weight plus the weight of the hanger equals the

required normal load. Note the reading of the vertical displacement dial gauge.

4.Remove the locking screws so that the parts are freed to move against each other. By

turning the racing screws, raise the upper part slightly above the lower parts by about 1

mm.

5.Conduct the test by applying horizontal shear load to failure or to 20 per cent longitudinal

displace me-. whichever occur first. The rate of strain may vary from 1 to 2.5 mm per minute.

Start the stop wan:: immediately at the start of the application of the shear load. Take the

readings of proving ring gauge, longitudinal displacement gauge and vertical displacement

gauge at regular time intervals.

6.At the end of the test, remove specimen from the box and determine its final water

content. Rer^_: the above steps on three or four identical specimens, under varying normal

loads In many engineering problems such as design of foundation retaining walls. Slab

bridges. Piping sheet piling the value of the angle of internal friction and cohesion of the soil

involved are required for the design. Direct shear test is used to predict these parameters

quickly. The laboratory reports cover the laboratory procedures for determining these

values for cohesion less soil.

We have taken undisturbed soil sample from medical college site with the

help of test mould inserting fully in the soil. The mould of 60 mm x 60 size after cutting all the

edges sharply was taken out the obtained soil sample was placed in the direct shear box.

Horizontal dial gauge in attached to the shear box from which division were obtained corresponding to which shear stress value was calculatedObservation of test shown next page

Normal stress kg/cm2 Shear stress kg/cm2

0.1 0.832

0.2 0.850


MAJOR PROJECT IN CIVIL ENGINEERING 8 TH SEM. 0.3 0.862

The graph was plotted between normal stress and shear stress which was a straight line. The

graph was shown in fig –

Result- The Value obtained from the observation table for was plotted on graph to get the

value of cohesion (C) and angle of internal friction (ø)

1. From fig –

C = 0.82 kg/cm2

ø= 80

Note- typical photo views of direct shear apparatus is shown in fig



Pavement design by C.B.R. method

The California bearing ratio test is penetration test meant for the evaluation of sub

grade strength of roads and pavements. The results obtained by these tests are used with

the empirical curves to determine the thickness of pavement and its component layers. This

is the most widely used method for the design of flexible pavement. This instruction sheet

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

remoulded /compacted soil specimens, both in soaked as well as unsoiled state.

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.

C.B.R. = [Test load/Standard load] 100


MAJOR PROJECT IN CIVIL ENGINEERING 8 TH SEM. The following table gives the standard loads adopted for different penetrations for the

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

Equipments and tool required

1. Cylindrical mould with inside dia 150 mm and height 175 mm, provided with a

detachable extension collar 50 mm height and a detachable perforated base plate 10

mm thick.

2. Spacer disc 148 mm in diameter and 47.7 mm in height along with handle.

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

mm.

4. Weights. One annular metal weight and several slotted weights weighing 2.5 kg

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

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

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

indicating device.

6. Metal penetration piston 50 mm diameter minimum of 100 mm in length.

7. Two dial gauges reading to 0.01 mm.

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



C.B.R. APPRATUS

Penetration Test (Unsoaked/soked)

(CBR - 1:0% Oversize Fraction)

1. Proving Ring Constant, 1 Div = 2.03 kg.

2. Area of Plunger = 19.625 cm2

3. Surcharge Mass = 5.0 kg



Pavement layer Thickness by C.B.R. method

Design of pavement design of 1 km road of site front at medical college. It is desired to use

the following material for different layers.

1 Compacted sandy soil with 4% CBR 2

2 Poorly graded gravel with 14% CBR

3 Well graded gravel with 50% CBR

4 Minimum thickness of bituminous concrete surface may

be taken as 8 cm

The traffic survey reveled the pressure ADT of commercial vehicle 1600. The Annual

rate of growth of traffic is found to be 6 percent. The pavement contraction is to be

completed in two year other the last traffic count.

Design the pavement section by CBR method as recommended by IRC Discuss the limitation

of CBR method of pavement design in the light of the above result.

Similarly the thickness of pavement required over poorly graded of CBR 14% and well graded

a ravel of CBR 50% are 27 cm and 12 cm

The designed pavement is shown in Fig.

12 cm bituminous surface

15 cm well graded gravel CBR = 50%

18 cm poorly graded gravel CBR = 14%

25 cm competed soil CBR = 4%

CBR (2.72%) of fine salty and clayed soil



Pavement design



TestING Of pavement materials

The materials required for the construction of any pavement structure or highways can

be broadly divided into the following three categories.

1. soil

2. bituminous materials and,

3. aggregates

1. STONE AGGREGATES :

Aggregates form the major portion of pavement structure and they from the prime

materials used in pavement construction. Aggregates have to bear stresses occurring due to

the wheel loads on the pavement and on the surface course they also have to resist wear

due to abrasive action traffic. These are used in pavement construction in cement concrete,

bituminous concrete and other bituminous constructions and also as granular base course

underlying the superior pavement layers. Therefore the properties of the aggregates are of

considerable significance to the highway engineers.

Desirable Properties of Road Aggregates :

Strength : The aggregates to be used in road construction should be sufficiently strong to

withstand the stresses due to traffic wheel load. The aggregates which are used in top layers

of the pavements, particularly in the wearing course have to be capable of withstanding high

stresses in addition to wear and tear ; hence they should possess sufficient strength

resistance to crushing.

Hardness : The aggregates used in the surface course are subjected to constant rubbing or

abrasion due to moving traffic. They should be hard enough to resist the wear due to

abrasive action of traffic. Abrasive action may be increased due to presence of abrasive

material like sand between the tyres of moving vehicles and the aggregates exposed at the

top surface. This section may be severe in the case of steel tyred vehicles. Heavy wheel loads

can also cause deformations on some types of pavement resulting in relative movement of


MAJOR PROJECT IN CIVIL ENGINEERING 8 TH SEM. aggregates and rubbing of aggregates with each other within the pavement layer. The

mutual rubbing of stones is called attrition , which also may cause title wear in the

aggregates ; however attrition will be negligible or absent in most of the pavement layers.

Toughness : Aggregates in the pavements are also subjected to impact due to moving wheel

loads. Sever impact like hammering is quite common when heavily loaded steel tyred

vehicles move on water bound macadam roads where stone protrude out especially after the

monsoons. Jumping of the steel tyred wheels from one stone to another at different levels

causes severe impact on the stones. The magnitude of impact would increase with the

roughness of the load surface , the speed of the vehicle and other vehicular charactertistics.

The resistance to impact or toughness is hence another desirable property of aggregates

Durability : The stone used in pavement construction should be durable and should resit

disintegration due to the action of weather. The property of the stones to withstand the

adverse action of weather may be called soundness. The aggregates are subjected to the

physical and chemical action of rain and ground water, the impurities there-in and that of

atmosphere. Hence it is desirable that the road stones used in the construction should be

sound enough to withstand the weathering action.

Shape of Aggregates : The size of the aggregates is firs qualified by the size of square sieve

opening through which an aggregates may pass, and not by the shape. Aggregates which

happen to fall in a particular size range may have rounded, cubical , angular flaky or

elongated shape of particles. It is evident that the flaky and elongated particles of the same

stone. Hence too flaky and too much elongated aggregates should be avoided as far as

possible. Rounded aggregates may be preferred in cement concrete mix due to low specific

surface area and better workability for the same proportion of cement paste and same

water cement ratio, whereas rounded particles are not preferred in granular base course,

WBM construction and bituminous construction as the stability due to interlocking of

rounded particles is less. In such constructions angular particles are preferred. The voids

present in a compacted mix of coarse aggregates depends on the shape factors , highly

angular flaky and elongated aggregates have more voids in comparison with rounded

aggregates.


http://www.highwaysmaintenance.com/HRA/PrecoatC1.jpg%00%E5%A1%B9%EF%92%81%E1%B4%BB%E4%A1%BF%E2%B2%AF%E5%B6%82%E8%97%84%E6%8C%A7%00%00%EA%AE%A5


Tests for PAVEMENT aggregates :

In Order to decide the suitability of the road stones for use in construction ,

the following tests are carried out :

(a) Crushing test

(b) Abrasion test

(c) Impact Test

(d) Soundness

(e) Shape test

AGGREGATE CRUSHING TEST :

The strength of coarse aggregate may be assessed by aggregate crushing test. The

aggregate crushing value provided a relative measure of resistance to crushing under

gradually applied compressive load. To achieve a high quality of pavement , aggregates

possessing high resistance to crushing a low aggregate crushing value are preferred.

The apparatus for the standard test consist of a steel cylinder 15.2cm diameter with

a base plate and a plunger , compression testing machines, cylindrical measure of diameter

11.5cm and height 18cm , tamping rod and sieves. The sketch of the test cylinder and

accessories.

Dry aggregates passing 12.5mm IS sieve and retained on 10 mm sieve is filled in the

cylindrical meause in three qual layer being ramped 25 times by the tamper. The test sample

is weighted (equal to W1g) and placed in the test cylinder in three equal layers , tamping

each layer 25 times. The plunger is placed on the top of specimen and a load of 40 tonnes is

applied at a rate of 4 tonnes per minute by the compression machine. The crushed

aggregate is removed and sieved on 2.36 mm IS sieve. The crushed material which passes

this sieve is weighted equal to W2g. The aggregate curshing value is the percentage of the

crushed material passing 2.36mm sieve in terms of original weight of the specimen


MAJOR PROJECT IN CIVIL ENGINEERING 8 TH SEM. Aggregate crushing value = 10W2 percent

W1

The strong aggragates possess low aggregate crushing value. The aggregate crushing

value for surface course should be with in 30 % and for base course it should not exceed

45% .

ABRASION TESTS :

Due to the movements of traffic the road stones used in the surface course

are subjected to wearing action at the top. Hence road stones should be hard enough to

resist the abrasion due to the traffic. Abrasion tests are carried out to test the hardness

property of stones and to decide whether they are suitable for the different road

construction works.



Impact Test :

A test designed to evaluate the toughness of stone of the resistance of the

aggregates to fracture under repeated impacts is called impact test. The aggregate impact

test is commonly carried out to evaluate the resistance to impact of aggregates and has

been standardized by ISI.

The aggregate impact value indicates a relative measure of resistance of aggregate

to impact, which has a different effect then the resistance to gradually increasing

compressive stress. The aggregate impact testing machine consists of a metal base and a

cylindrical steel cup of internal diameter 10.2 cm and depth 5cm in which the aggregate

specimen is placed. A metal hammer of weight of 13.5-14.0 kg having a free fall from a

height 38 cm is arranged to drop through vertical guides. The aggregates impact machine.

Aggregate specimen passing 12.5mm sieve and retained on 10mm sieve is filled in

the cylindrical measure in 3 layers by tamping each layer by 25 blows. The sample is

transferred from the measure to the cup of the aggregate impact testing machine of

compacted by tamping 5 times. The hammer is raised to a height of 38 cm above the upper

surface of the aggregate in the cup is allowed to fally freely on the specimen. After

subjecting the test specimen to 15 blows, the crushed aggregate is sieved on 2,36 mm sieve.

The aggregate impact value is expressed as the percentage of the fine formed in terms of the

total weight of the sample.



Shape Tests

The particle shape of aggregate mass is determine by the percentages of flaky and

elongated particles contained in it and by its angularity. The evaluation of shape of the

particles made in terms of flakiness index, elongation index and angularity number.

the flakiness index of aggregate is the percentage by weight of aggregate particles

whose least dimension/ thickness is less than three fifths or 0.6 of their mean dimension. The

test is applicable to sizes larger than 6.3 mm. Standard thickness gauge is used to gauge the

thickness of the samples. The sample of aggregates to be tested is sieved through a set of

sieves and separated into specified size ranges. Now to separate the flaky material , the

aggregates which pass through the appropriate slot would the 0.6 of the average of the size

range If the size range of aggregate in a group is 16-20mm, the width of the slot to be

selected in thickness gauge would be 18x0.6 =10.8mm. The flaky material passing the

appropriate slot from sample taken from the different size range is W, the flatness index is

given by 10w/W percent , or in other words it is the percentage of flaky materials, the widths

of which are less than 0.6 of the mean dimensions. It is desirable that the flatness index

aggregates used in road construction is less than the 15 percent and normally does not

exceed 25 percent.

Angularity Number :

Based on the shape of the aggregate particles, they may be classified as rounded.

irregular or partly rounded, angular and flaky , Angular particles posses well defined edges

formed at the intersection of roughly plane faces and are commonly found in aggregates

prepared by crushing of rocks. Since weaker aggregates may be crushed down during the

test. Angularity or absence of rounding of the particles of an aggregate is a property which is

of importance because it affects the ease of handling a mixture of aggregate and binder.

The determination of angularity number of an aggregate is essentially a laboratory method

intended for comparing the properties of different aggregates for mix design purposes.



BITUMINOUS MATERIALS

Bituminous binders used in pavement construction works include both bitumen and tar.

Bitumen is a petroleum product obtained by the distillation of petroleum crude where-as

road tar is obtained by the destructive distillation of coal or wood. Both bitumen and tar

have similar appearance , black in colour though they have different charactertistics. Both

these materials can be used for pavement works.

Bitumen is hydrocarbon material of either natural or pyrogenous origin, found in

gaseous , liquid , semisolid or solid from and is completely soluble in Carbon disulphide and

in carbon tetra chloride. Bitumen is a complex organic material and occurs either naturally

or may be obtained artificially during the distillation of petroleum. Bituminous materials are

very commonly used in highway construction because of their binding and their water

proofing properties.

When the bitumen contains insert material or minerals , it is some times called

asphalt. Asphalt is found as deposits in the form of natural asphalt or rock asphalt.

The grades of bitumen used for pavement construction work of roads and airfields

are called paving grades and those used for water proofing of structures and industrial floors

etc. are called industrial grades. The paving bitumen available in India are classified into two

categories.

(i) paving bitumen from Assam petroleum , denoted as A-type and designated as graded

A35 , A90 etc.

(ii) paving bitumen from other sources denoted as S-type and designated as graded S35

S 90 etc.



Types of Bituminous Materials :

Bituminous materials used in highway construction may be broadly divided as

:

(i) Bitumen and

(ii) Tar

Bitumen may be further divided as petroleum asphalt or

bitumen and native asphalt.

There are different forms in which native asphalt are available. Navtive asphalt are

those which occur in a pure or nearly pure state in nature. Native asphalts which are

associated with a large proportion of mineral matter are called rock asphalts. The viscosity

of bitumen is reduced some times by a volatile diluent ; this material is called cutback. When

bitumen is suspended in a finely divided condition in a aqueous medium and stabilized with

an emulsifier, the material is known as emulsion. Tar is the viscous liquid obtained when

natural organic materials such as wood and coal are carbonized or destructively distilled in

the absence of air. Processing of bitumen and bituminous products is diagrammatically.

Bitumen :

Crude petroleum obtained from different places are quite different in their

composition The portion of bituminous material present in the petroleums may widely differ

depending on the source. Almost all the crude petroleums should be dehydrated first before

carrying out the distillation. General types of distillation processes are fractional distillation

and destructive distiallation. Infractional distillation the various volatile constituents are

separated at successively higher temperature without substantial chemical change.

Requirements of Bitumen :

desirable properties of bitumen depend on the mix type and the construction. The

general problems which using bitumen in paving mixtures are :

(i) mixing

(ii) attainment of desired stability of the mix

(iii) to maintain the stability under adverse weather conditions.

(iv) to have sufficient adhesion with the aggregates in the mix in presence of water.



Tests on Bitumen

Bitumen is available in a variety and grades. To judge the suitability of these binders

various physical tests have been specified by agencies like ASTM , Asphalt Institute , British

standard Institution and the ISI. These tests include penetration test. ductility tests, softening

point test and viscocity test For Classifying bitumen and studying the performance of

bituminous pavements , the penetration and ductility tests are essential. The other tests like

softening point and flash and fire point tests are more been recornized that the above tests

are not sufficient to define the temperature possessing same penetration value at a specified

temperature may exhibit entirely different viscous charactertistics at the application or

service temperatures. These tests therefore may need intensive correlation with

fundamental property like viscocity.

The various tests on bituminous materials are :

(a) Penetration tests

(b) Ductility test

(c) Viscocity test

(d) Float Test

(e) Specific gravity test

(f) Softening point test

(g) Flash and fire point test

(h) Solubility test

(i) Spot Test

(j) Loss on heating test

(k) Water content test



Penetration test

The penetration determines the hardness or softness of bitumen by measuring the depth in

tenths of a millimeter to which a standard loaded needle with penetrate vertically in five

seconds. The sample is maintained at a temperature of 250C . The concept of penetration

test. Indian Standard Institution has standardized the equipment and test procedure.

The penetrometer consists of a needle assembly with a total weight of 100g and

device for releasing and locking in any position. There is a graduated dial to read to

penetration values to 1/10th of a millimeter.

The bitumen is softened to a pouring consistency, stirred thoroughly and poured into

containers to a depth at least 15mm in excess of the expected penetration. The sample

containers are then placed in a temperature controlled water bath at a temperature 25 0C for

one hour. At least three penetration tests are made on this sample by testing at distances of

at least 10mm apart . After each test the needle is disengaged and wiped with benzene and

dried. The depth of penetration is reported in on-tenth millimeter units. The mean value of

three measurements is reported as a penetration value. It may be noted that the penetration

value is largely influenced by an inaccuracy as regards pouring temperature size of needle,

weight placed on the needle and the test temperature.

The penetration value of various types of bitumen used in pavement construction in

this country range between 20 and 225, 30/40 and 80/100 grade bitumen are more

commonly used, depending on construction type and climatic conditions. In hot climates a

lower penetration grade bitumen like 30/40 bitumen is preferred.



Ductility test :

In the flexible pavement construction where bitumen binders are used, it is important

that the binders from ductile this films around the aggregates. This serves as a satisfactory

binder in improving the physical interlocking of the aggregate bitumen mixes. Under traffic

loads the bitumen pavement layer is subjected to repeated deformation and recoveries. The

binder material which does not possess sufficient ductility would crack and provide pervious

pavement surface. Ductility test is carried out on bitumen to test this property of the binder.

The test is believed to measure the adhesive property of bitumen and its ability to stretch.

The bitumen may satisfy the penetration value., but may fail to satisfy the ductility

requirements. Bitumen paving engineer would however want that both test requirements

are satisfied in the field jobs. Penetration and ductility tests cannot in any case replace each

other.

The ductility is expressed as the distance in centimeters to which a standard briquette

of bitumen can be stretched before the thread breaks. The test is conducted at 270C and at a

rate of pull of 50mm per minute. The test set up is the cross section at minimum width of the

specimen is 10mm x 10mm.

The ductility machine functions as a constant temperature water bath with a pulling

device at a pre-calibrated rate. Two clips are thus pulled apart horizontally at a uniform

speed of 50mm per minute.

The bitumen sample is heated and poured in the mould assembly placed on a plate.

The samples along with the moulds are cooled in air and then in water bath maintained at

270C . The excess bitumen material is cut and the surface is leveled using a hot knife. The

mould assembly containing sample is replaced in water bath the ductility testing machine 85

to 95 minute. The sides of the mould are removed, the clips hooked on the machine and the

pointer is adjusted to zero. The distance up to the point of breaking of thread is reported in

centimeters as ductility value. The ductility values gets seriously affected by factors such as

pouring temperature , dimensions of briquette, level of briquette in the water bath , presence

of air pockets in the modulus briquettes, test temperature and rate of pulling.

.



Specific gravity test :

The density of a bitumen binder is a fundamental property frequently used as an aid

to classify the binders for use in paving jobs. In most applications the bitumen is weighed but

finally when used with aggregate system , the bitumen content is converted on volume basis

using density values. The specific gravity value of bitumen is also useful in bituminous mix

design. The density of bitumen is greatly influenced by its chemical composition. Increased

amounts of aromatic type compounds or mineral impurities cause an increase in specific

gravity.

The specific gravity of bituminous materials is defined as the ratio of the mass of

given volume of the substance to the same of an equal volume of water, temparature of

both being 270C . The specific gravity is determined either by using a pycnometer or by

preparing a cube shape specimen in semi solid or solid state and by weighing in air and

water.

Generally the specific gravity of pure bitumen is in the range of 0.97 to 1.02. The

specific gravity of cutback bitumen may be lower depending on the type and proportion of

diluent used. Tars have specific gravity ranging from 1.10 to 1.25.



CONCLUSION

Site investigation or subsoil investigation are done for obtaining the information about

subsurface condition at the site of proposed construction. Site investigation in one form or

the other is generally required for every big engineering project. Information abot the

surface and subsurface features is essential for the design of structures and for planning

constructing. The following results are obtained from the medical college site :-

1. Natural moisture content of the given soil sample varies between 17% - 20%.

2. Specific gravity of the given soil sample varies between 2.6 to 2.7

3. From sieve analysis one thing is clear that the soil is fine and it is clay because

more than 50% soil passes through the 75 micron is sieve.

4. The liquid limit of soil is very high and varies between 48% to 61% hence, it

offers low shearing resistance and the shear strength of soil is relatively lower

than the other soil. Also soil will absorb more water due to the presence of

clay particles.

5. Plastic limit of given soil sample varies between 24% to 26% and the plasticity

index of soil lies between 28% to 34%.

6. Maximum dry density of a given soil samples varies between 1.87 gm/cm to

1.89 gm/cm

7. The value of cohesion intercept and angle of internal friction obtained from

direct shear test lies between 0.74% kg/cm2 to 0.82 kg/cm2 and 70 to 80

respectively.

8. Calculated value of California bearing ratio is 17 cm of pavement design

thickness.

9. Thickness of bituminous surfacing = 12 cm.


MAJOR PROJECT IN CIVIL ENGINEERING 8 TH SEM. 10. Thickness of well graded = 15 cm.

11. Thickness of Poorly graded gravel = 18 cm.

12. Thickness of competed sub graded = 25 cm.

REFERENCES

1. SOIL MECHNICS AND FOUNDATION ENGINEERING BY B .C. PUNMIA

2. SOIL MECHNICS AND FOUNDATION ENGINEERING BY DR. K. R. ARORA

3. BASIC AND APPLIED SOIL MECHANIC BY RANJAN GOPAL & RAO

4. SOIL TESTING AND LABORATORY MANUAL BY APPARAO K.V.S. & V.C.S. RAO

AND FROM

5. INTERNET

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