Analysis and Execution of Road Work PDF
Analysis and Execution of Road Work PDF
Analysis and Execution of Road Work PDF
ON NH-5
Bachelor of Technology
In
Civil Engineering
By
SAMARTH AGARWAL
(08248A0101)
KG RAHUL VARMA
(08241A0132)
STUDENT DECLARATION
We hereby declare that the project entitled " ANALYSIS & EXECUTION OF
ROADWORKS ON NH-5" is the work done by us during the academic year 2011-2012
and is submitted in partial fulfillment of the requirements for the award of degree of
bachelor of technology in CIVIL ENGINEERING from JNTU, Hyderabad.
(08241A0160)
ACKNOWLEDGEMENT
Success is epitome of hard work, cogency for fulfilling the mission, indefatigable perseverance
and most of all encouraging guidance and Steering.
It gives us an immense pleasure to express our gratitude to Prof. Dr. G. Venkata Ramana,
Head of Department of Civil Engineering for his esteemed guidance and able supervision during
the course of the project. His constant encouragement and co-operation made this project a
success.
We are especially thankful to Dr. J.N. Murthy, Principal, GRIET, Hyderabad, for providing the
necessary facilities to carry out the work successfully.
We would like to express our sincere thanks to BSCPL Infrastructures Limited for providing
us an opportunity to complete our industrial oriented main project successfully, which is a part of
course curriculum. This training would not have been successfully completed without the
guidance and support of Mr. K. Sambasiva Rao(Project Manager), Mr. N. Srinivas (Q.C
Laboratory In charge), Mr. Shiva Ram Reddy (Surveying In charge), Mr. Abdul Khadar
(Structures Incharge) and the entire team. We are deeply indebted to project team members who
were always ready to help us during project time.
We are also thankful to our internal project guide B.H.Mahesh Chandrakanth for his guidance in
our project.
Samarth Agarwal
08248A0101
08241A0107
K Vivek Babu
08241A0160
KG Rahul Varma
08241A0132
ABSTRACT
Road Transport is vital to India's economy. It enables the country's transportation sector
contribute 4.7 percent of Indias gross domestic product, in comparison to railways that
contributed 1 percent, in 2009-2010, despite railways handling of passenger and pure cargo.
Road transport has gained in importance over the years despite significant barriers and
inefficiencies in inter-state freight and passenger movement compared to railways and air. The
government of India considers road network as critical to the country's development, social
integration and security needs of the country. India's road network carries over 65 percent of its
freight and about 85 percent of passenger traffic. Indian road network is administered by various
government authorities, given India's federal form of government. National highways connect
capitals, important places, ports and places of strategic importance of various states. Though
national highways account for only 2% of the total road length, they carry nearly 1/3 of the total
traffic.
Flexible pavement is composed of a bituminous material surface course and underlying base and
sub base courses. The bituminous material is more often asphalt whose viscous nature allows
significant plastic deformation. Most asphalt surfaces are built on a gravel base, although some
'full depth' asphalt surfaces are built directly on the sub grade. Depending on the temperature at
which it is applied, asphalt is categorized as hot mix asphalt (HMA), warm mix asphalt, or cold
mix asphalt. Flexible Pavement is so named as the pavement surface reflects the total deflection
of all subsequent layers due to the traffic load acting upon it. The flexible pavement design is
based on the load distributing characteristics of a layered system.
It transmits load to the sub grade through a combination of layers. Flexible pavement distributes
load over a relatively smaller area of the sub grade beneath. The initial installation cost of a
flexible pavement is quite low which is why this type of pavement is more commonly seen
universally. However, the flexible pavement requires maintenance and routine repairs every few
years.
Highway surveys involve the location of alignments and computation of volumes materials that
must be added, removed, or moved. It initially requires a topographic survey of the site. For large
projects, photographic method will be used to develop the base map. The base map is used by
surveyors and other professional to create a base plan for the project. After the alignment has
been established, the quantities of earth that must be added or removed are computed. The goal
of most projects is to minimize the hauling distances of the earth. This is done using mass
diagrams. Eventually surveyors layout the elevation and slope of the various sub-grades, base,
and top coat materials. The end result is a smooth alignment with smooth transitions from
straight to curved sections allowing for safe public transportation.
Project by
Samarth Agarwal
(08248A0101)
(08241A0107)
K Vivek Babu
(08241A0160)
KG Rahul Varma
(08241A0132)
NOTATIONS
ACWC
AIV
BC
Bituminous concrete
DBM
GSB
NH
National Highway
NHAI
PUP
QC
Quality control
RCC
VUP
WMM
BC
Black Cotton
MDD
OMC
CBR
WBM
DLC
IRC
CONTENTS
S. No.
I.
Title
Page No.
Introduction
01
Classification of Roads
02
III.
06
IV.
16
II.
a. Site Investigation
16
b. Site Clearance
20
V.
26
VI.
29
31
VII.
VIII.
IX.
X.
XI.
42
56
Drawings
Bibliography
72
Introduction
National Highway 5 (NH-5) is a major National Highway in India that runs along Indias east
coast through the states of Orissa, Andhra Pradesh and Tamil Nadu. The northern terminal is at
Jharpokharia in Orissa and the southern terminal is at Chennai in Tamil Nadu. NH 5 is a part of
the golden quadrilateral project undertaken by National Highways Development Project. Under
the new national highway numbers NH 5 is renamed as NH 16. NH 5 runs for a distance of 1533
km.
In Tamil Nadu NH 5 starts from Chennai and shortly enters Andhra Pradesh from
Gummidipundi.
In Andhra Pradesh, it passes through most of the coastal towns in nine coastal districts including
Nellore,
Ongole,
Chilakaluripet,Guntur,
Vijaywada,Eluru,Tanuku,Rajahmundry,
Tuni
Percent
Plain
0-10
2.
Rolling
10-25
3.
Mountains
25-60
4.
Steep
Greater than 60
Roadway width: the width of the roadway for single and two lane roads in plain and
rolling terrain is 12mts for National and State highways.
ii.
Carriageway width: The total width of the carriageway shall be determined in relation
to the design traffic and capacity of the roadway. The standard width shall be as indicated
below.
Single lane
3.75mts
7.0 mts
7.5mts
3.5mts
iii.
Pavement camber or cross fall: the camber or cross fall on straight sections of roads
should be as recommended in table given below for various types of surfaces. For a given
surface type, the steeper values may be adopted in areas having high intensity of rainfall.
1.7-2.0 %
(1 in 60 to 1 in 50)
2.0-2.5 %
(1 in 50 to 1 in 40)
2.5-3.0 %
(1 in 40 to 1 in 33)
Earthen
3.0-4.0 %
(1 in 33 to 1 in 25)
iv.
Horizontal alignment: the horizontal alignment should be fluent and blend well with the
surrounding topography. The curves should be sufficiently long and have suitable
transitions to provide pleasing appearance. Curve length should be at least 150mts or a
deflection angle of 5 degrees, and this should be increased by 30 meters for each one
degree decreases in the deflection angle. For deflection angles less than one degree, no
curve is required to be designed.
v.
Horizontal curves and super elevation: horizontal curve is a curve with end transitions
to provide change in direction to the centerline of a road. When a vehicle traverses a
horizontal curve, the centrifugal force acts horizontally outwards through the center of
gravity of the vehicle. The centrifugal force acting on a vehicle negotiating a horizontal
curve have a tendency to overturn the vehicle outwards about the outer wheels and
tendency to skid the vehicle laterally, outwards. In order to counteract the effect of
centrifugal force, the outer edge of the pavement is raised with respect to the inner edge
thus providing a transverse slope throughout the length of the horizontal curve. This
transverse inclination to the pavement surface is called super elevation or cant or
banking
Super elevation required on horizontal curves should be calculated from the following formula
e=V2/225R
Where,
e= super elevation in meter per meter
V= speed in km/h
R= Radius in meters
vi.
Vertical curves
Definitions:
i.
Vertical Curve: Vertical curves have the shape of a parabola and are used to produce a
gradual change between tangent grades.
ii.
Point of Vertical Intersection (PVI): The PVI is the point where the extension of two
tangent grades intersect
iii.
Point of Vertical Curvature (PVC). The PVC is the point at which the tangent grade ends
and the vertical curve begins.
iv.
Point of Vertical Tangency (PVT). The PVT is the point at which the vertical curve ends
and the tangent grade begins.
v.
Grade Slopes (G1 or G2). The grade slope is the rate of slope between two adjacent
PVI's expressed as a percent. The numerical value for percent is the vertical rise or fall in
feet for each 100 feet of horizontal distance. Upgrades in the direction of stationing are
identified as plus (+). Downgrades are identified as minus (-).
Sub grade soil is an integral part of the road pavement structure as it provides support to the
pavement as its foundation. The main function of the sub grade is to give adequate support to the
pavement and for this the sub grade should possess sufficient stability under adverse climatic and
loading conditions. The formation of wave, corrugations, rutting and shoving in black top
pavements are generally attributed to poor sub grade conditions. When soil is used in
embankment construction, in addition to stability, incompressibility is also important as
differential settlement may cause failure. Soil is used in its natural form (gravel and sand) or in a
processed form (stabilized layer) for pavement construction. Soil is also used as a binder in
water-bound macadam layers. Soil is therefore, considered as one of the principal highway
materials. The foundation of other cross-drainage structures (culverts, bridges and retaining
walls) rests on soils and their stability depends on the soil strength, knowledge of soil properties
is necessary to select the embankment material, pavement structure, drainage system and
foundation of structures. When a high embankment rests on soft ground, its stability can be
predicted by studying the properties of soil. Frost action, common in high altitudes, can be taken
care of if the soil properties are well known. Soil consists mainly of minerals matter formed by
the disintegration of rocks, by the action of water, frost, temperature, and pressure or by plant or
animal life. Based on the individual grain size of the soil particles, soil have been classified as
gravel, sand, silt, and clay.
Gravel
80-4.75 mm
Sand coarse
4.75- 2.00 mm
Medium
2.00-0.475 mm
Fine
0.475-0.075 mm
Silt
0.075- 0.002 mm
Clay
<0.002mm
Types of soil: Soils occur in a fairly wide variety in our country. Some of the major soil types
found in the country are:
i.
Alluvial soils: These are mostly found in the indo-gangatic plane. Generally, these are
composed of broadly matching fractions of sand, silt, and clay, and make fair to good sub
grade material.
ii.
Fine sand: It is confined mostly to desert areas in the north western part of the country.
This soil lacks binder fraction and is not well graded.
iii.
Coastal soils: The sands/sandy soils forming the coastal alluvium usually make a good
sub-grade.
iv.
B.C soils: Black cotton soils occur in parts of Madhya Pradesh, Maharashtra, Andhra
Pradesh and Karnataka. This soil is characterized by pronounced volume changes
(swelling upon wetting and shrinkage after drying) and low strengths at high moisture
content.
v.
Red gravelly soils: The moorums and red gravelly soils are found in various pockets and
are less problematic.
The wide range of soil types as highway construction materials have made it obligatory on the
part of the highway engineer to indentify and classify the different soils. The classification of soil
as per IS nomenclature, the general range of the maximum dry densities of these materials and
their approximate CBR values are given below.
CBR %
GW
2.00 2.24
60 90
GP
1.76 2.24
25 60
GM
2.08 2.22
20 80
GC
1.92 2.24
20 80
SW
1.76 - 2.08
20 60
SP
1.59 - 1.92
10 30
SM
1.92 2.16
10 40
SC
1.68 2.08
15 50
ML
1.60- 2.00
5 20
CL
1.60 2.00
5 15
OL
1.44 1.60
38
MH
1.28 1.60
38
CH
1.44 1.76
35
CH
1.28 1.68
24
(fines<5%)
Poorly graded gravel and gravel sand mixture (fine
< 5%)
(fines>12%)
(Fines >12%)
sandy or silty.
Road aggregates:
These have to bear the stresses due to the wheel loads and hence they should possess sufficient
strength to resist crushing. They should be hard enough to resist wear due to abrasive action of
traffic. The aggregates in the pavement are also subjected to impact hence toughness is another
desirable property of aggregates. The stones used should be durable and resist disintegration due
to action of weather, this property is called soundness.
The following are the most commonly available rocks in India from which road aggregates can
be obtained.
Type of Rock
Basalt
Properties
Hard and durable, resistant to
Suitability
Good for base courses
Limestone
Aggregates may have rounded cubical angular flaky or elongated shape of particles. The flaky or
elongated particles will have less strength and durability hence too flaky and elongated particles
should be avoided. The following are the physical requirements of coarse aggregates used for
WBM as per IS 2386.
Los Angles abrasion value
40 percent (Maximum)
Or
Aggregate impact value
30 percent (Maximum)
30 percent (Maximum)
Grading requirements: The WBM is carried out in layers. The coarse aggregates for each layer
should confirm to any of (3) grading below. The use of grading no 1 shall be restricted to sub
base courses only.
Size and grading requirements of coarse aggregates for water bound macadam.
Grading No.
Thickness and
Size range
aggregate per
IS sieve
Percent by
designation
weight passing
10 sqm.
1
10 mm
the sieve
125 mm
100
1.21 to 1.13
90 mm
90-100
cums.
63 mm
25-60
45 mm
0-15
22.4 mm
0-5
90 mm
100
0.91 to 1.01
63 mm
90-100
cums.
53 mm
25-70
45 mm
0-15
22.4 mm
0-5
75 mm
90 mm to 45 mm
63 mm to 45 mm
75 mm
53 mm to 22.4
63 mm
100
0.91 to 1.07
mm
53 mm
95-100
45 mm
65-90
22.4 mm
0-10
11.2 mm
0-5
cums.
The compacted thickness for a layer with grading no 1 shall be 100 mm while for layer with other
grading i.e. 2&3 shall be 75 mm.
Application of screenings:
To fill voids in the coarse aggregates, screenings are generally necessary and shall consist if the
same material as the coarse aggregate. As far as possible, the screening material should conform
to grading given in the table.
Grading
Size of screening
IS sieve designation
classification
A
Percent by weight
passing the sieve
13.2 mm
11.2 mm
13.2 mm
100
11.2 mm
95-100
5.6 mm
15-35
180 microns
0-10
11.2 mm
100
5.6 mm
90-100
180 microns
15-35
Gravel: Non-Plastic material such as moorum or gravel may also be used for filling the voids in
the coarse aggregates provided liquid limit and plasticity index of such material are below 20 and
6 respectively and fraction passing 75 microns sieve doesnt exceed 10%.
Bituminous material:
Bitumen is a viscous liquid, semisolid or solid material, colour varying from black to dark brown
having adhesive properties consisting essentially hydrocarbons is derived from distillation of
petroleum crude or natural asphalt and soluble in carbon disulphide. Bituminous materials used
for paving purposes are penetration grade bitumen and liquid bitumen (cutbacks & emulsion).
The bituminous binder should possess the following qualities.
Adequate viscosity at the time of mixing and compaction.
Not highly temperature susceptible.
Should not strip from aggregate in presence of water.
Penetration test
Viscosity test
Ductility test
2. Composition Test
Solubility test
Distillation test
Spot test
Safety test to indicate the max temperature to which the bituminous material can be
safely heated.
Measurement of penetration a 100 gm standard steel needle into a bitumen binder kept
into a bitumen binder kept at 25 degrees within 5 sec is known as penetration value.
Viscosity is its important physical property low viscous binder may flow off the
aggregate during transit from mixing plant to site and a high viscous material may
provide an unworkable mix. Viscometer is used to measure the viscosity of the bitumen.
The ductility of a bituminous material is measured by the distance in centimeters to
which it will elongate before breaking when a briquette specimen of the material of the
form is pulled apart at a specified speed (50 mm/min) and specified temperature of 27
degrees- bituminous briquette is subjected to rupture in the testing machine.
Softening point: The temperature at which the bitumen attains the particular degree of softening
under specified condition of test- measured with ring and ball apparatus.
Flash point: It is the lowest temperature at which the vapour of bitumen momentarily takes fire
in the form of a flash under specified condition of test- pensky-martens tester is the apparatus
used to test flash point.
Fire point: It is the lowest temperature at which the material gets ignited and burns under
specified condition of test- measured with pensky-martens tester.
Properties of paving bitumen:
Specific gravity at 27 degrees
1.12-1.28
0.50
175
45-60
Penetration at 25 degrees
80-100
Ductility at 24 degrees
75
The aggregates used in bituminous works shall satisfy the following physical requirements:
Property
Test
Specification
Cleanliness (Dust)
Particle shape
Max 30%
index
Strength
Durability
Max 35%
Max 27%
Soundness
Sodium sulphate
Max 12%
Magnesium sulphate
Max 18%
Water absorption
Water absorption
Max 2%
Stripping
Bituminous courses:
Bituminous courses of different specifications are laid on WBM/WMM base or existing BT
surface. A PRIME COAT over macadam base at the rate of 6 to 9 kgs/10 sqms and TACK
COAT of 2 to 3 kgs/sqms over existing BT surface shall precede the bituminous courses. The
specification for different classes of BT work varies with respect to size of aggregates and
quantity of bitumen used. The voids in bituminous surface will be sealed by application of seal
coat.
ii.
iii.
The level of DBM layer should be checked before laying bituminous course and if any
error is found, it should be corrected.
iv.
v.
Item of
Grade
Thickness
Nominal
Bitumen
Ref to
of layer in
aggregate
content %
MOST
mm
size
by weight
specification
20 mm
12 mm
2.8
511
Grade 1
80-100
40 mm
3.1 to 3.4
504
Grade 2
50-75
19mm
3.3 to 3.5
504
Grade 1
80-100
40mm
4.0
507
Grade 2
50-75
25mm
4.5
507
work
Premix
carpet
Bituminous
macadam
Dense
bituminous
macadam
Semi dense
Grade 1
35-40
13 mm
4.5
508
Grade 2
25-30
10mm
5.0
508
bituminous
concrete
Apart from conformity with grading and quality requirements individual ingredients the mix
shall meet the requirements of Marshall test.
Minimum stability(kg at 60 degree centigrade)
820 kgs
Flow (mm)
2-4
3-5
8-22
Desk Study
Site Reconnaissance
Preliminary report or feasibility study
Preliminary Ground Investigation - Planning of main GI
Preliminary report
Main Ground Investigation
Laboratory testing
Final report
Suitability: Are the site and surroundings suitable for the highway?
Design: Obtain all the design parameters necessary for the works.
Construction: Are there any potential ground or ground water conditions that would
affect the construction?
Materials: Are there any materials available on site, what quantity and quality?
Effect of changes: How will the design affect adjacent properties and the ground water?
Identify Alternatives: Is this the best location?
Desk study:
The desk study is work taken up prior to commencing the work on site and the Ground
Investigation. It should always be the first stage of the Site Investigation and is used to plan the
Ground Investigation. The work involves researching the site to gain as much information as
possible, both geological and historical.
Site reconnaissance:
The Site Reconnaissance phase of a site investigation is normally in the form of a walk over
survey of the site. Important evidence to look for is:
Hydrogeology: Wet marshy ground, springs or seepage, ponds or streams and Wells.
Slope Instability: Signs of slope instability include bent trees, hummocks on the ground
and displaced fences or drains.
Mining: The presence of mining is often signs of subsidence and possibly disused mine
shafts. Open cast mining is indicated by diverted streams replaced or removed
fence/hedge lines.
Access: It is essential that access to the site can be easily obtained. Possible problems
include low overhead cables and watercourses.
Ground investigation:
Ground investigation is taken to be that other than the information available from the walk over
survey as discussed previously.
There are two principal methods of investigating the ground conditions, trial pits and boreholes.
In addition, the reader should be aware of geophysical techniques such as seismic surveys, which
are not discussed here.
Sampling:
Sampling can be either undisturbed, of which in-situ testing is a form, or disturbed. On our site,
we used both disturbed and undisturbed/representative.
Reporting:
The Site Investigation report for a highway design scheme should answer all the questions set
out in the planning phase of the Investigation. This should include an assessment of the viability
of the proposed route and indication of any alternatives.
Included in the report should be a location of all the boreholes, trial pits, other excavations and
their logs. These logs should give as much information as possible on the soil and rock structure
as it is possible to obtain.
The soil and rock descriptions should be defined and should contain the information described
below:
Soil Description - Often remebered using the acronym MCCSSOW obviously!
Moisture Content - Dry, slightly moist, moist, very moist or wet. Not the measured value
just the way it appears in the hand.
Colour - This is an indicator of chemical and mineralogical content. Charts are available
but not often used.
Consistency - Loose or dense and other descriptions dependant on soil type. An
approximate relationship can be made between stifness and undrained shear strentgh (Cu)
and between density and the SPT 'N' Values.
Cu
Very Soft
<20
Very Loose
<4
Soft
20-40
Loose
4-10
Firm
40-75
Medium dense
10-30
Stiff
75150
Dense
30-50
Very stiff
>150
Very dense
>50
Origin - Try and identify geological area and stratographic unit. This is difficult and often
impossible
GroundWater Conditions - Depth to groundwater and any other observations.
Rock Descriptions - The acronym makers came up with CGTSWROS in a moment of inspiration
Cu(MPa)
Point Load
Strength(MPa)
>200
>12
100-200
6-12
Strong
50-100
3-6
Moderately
Strong
Term
Field recognition
Extremely
Strong
Very Strong
0.75-3
Moderately
weak
5-12.5
0.3-0.75
Weak
1.25-5
0.075-0.3
Very Weak
Crumbles in hand
<1.25
<0.075
Very Stiff
>0.3
Site clearance:
General:
Site clearing generally consists of the cutting and/or taking down, removal and disposal of
everything above ground level, including objects overhanging the area to be cleared such as
tree branches, except such trees, vegetation, structures or parts of structures and other things
which are designated in the contract to remain or be removed by others to which the
engineer directed to be left undisturbed.
The material to be cleared usually but not necessarily is limited to trees, stumps, logs, brush,
undergrowth, long grasses, crops, loose vegetable matter and structure.
The entire road area shall be cleared as described above, unless otherwise shown on the
drawing and/or directed by the engineer.
Setting out:
The right of way (R.O.W) shall be surveyed and set out before any site clearance is cleared
out. Wooden pegs usually indicate the surveyed rights of ways.
specialized equipment depending on the size and type of structures. Before commencing
explosive demolition all necessary permits and licenses will be obtained and a blasting plan
detailing the size of charges, locations of holes, system of detonation and safety precaution
will be forwarded to the engineer together with the request sheets.
Sequence of works:
Prior to the commencement of the site clearance, the following shall be carried out either
independently or jointly with the Engineers Representative.
I.
The right of ways (R.O.W) shall be surveyed and set out according to the data stated
in the drawings.
II.
III.
The above site clearance items shall be measured according to the method of
measurement jointly with the Engineers Representatives. The location of these
items shall be identified according to the survey data or offsets from the centerline
of the proposed alignment in road construction.
IV.
V.
Removal of landscaping trees and shrubs shall be carried out with the prior approval
of the concerned authority.
VI.
Fencing or others that are to be relocated or salvaged shall be carried out according
to the drawings or as per the instructions given by Engineer.
VII.
Obtain confirmation that the employer or relevant authority have acquired the right
of way lands.
VIII.
IX.
Solid waste dumps sites shall be predetermined within or outside the site for the
dumping of the site clearing materials.
X.
The site clearance then shall be proceeded to clear the trees, vegetation,
undergrowth, bushes and minor structures by hydraulic excavators or dozers.
material the engineer will be notified and the material will be sampled and tested for
continued suitability of use. If the changed material is considered to be Hard Rock a request
for approval for re classification will be submitted.
Slopes in cutting shall be trimmed mechanically to neat and even surfaces in accordance
with the designed gradients. The tolerance for widths of excavations shall not exceed the
dimensions shown on the drawings by more than 150mm or specified limits.
Erosion
protection measures if desired by the engineer shall be carried out after the completion of
trimming.
The construction of side drain shall follow closely to the slope trimming and surface water
shall be regulated to discharge to the side drain.
If directed by the engineer the slope of cutting shall be cleared of all rock boulders or rock
fragments, which move when, pressed by the crowbar.
The formation of sub grade on the cut area shall be sampled and tested for lab compaction,
lab CBR, and grading and index properties. If found to be suitable for sub grade this will be
compacted and tested as to CI.301 and CI.305. Request for approval for placing of sub base
will then be submitted. If there is likely to be a delay in immediately placing the sub base
then a protective layer 300mm thick shall be left in place above the sub grade level for
removal at a later date.
Machinery used:
i.
Excavator J.C.B. or Hitachi EX 100 for bulk excavation, loading on trucks and slope
trimming.
ii.
Dump truck For transporting cut materials from the cut area.
iii.
Bulldozer ripping & loosening of earth and rock mixed soil etc.
iv.
Grader for trimming to final level and maintaining the surface parallel to the finished
grade line.
Image: JCB
Image: Backhoes
General:
The area to receive fill shall be sampled and tested below topsoil in accordance with the
specification. If the test results indicate that the material is for suitable to receive fill then a
request of Approval starting compaction of existing ground will be submitted. Before
starting the compaction of the existing ground the topsoil will be stripped from the area,
either to a thickness agreed from the soil sampling holes or as directed on site by the
Engineer or his designated staff and afterwards measured by leveling. After compacting the
existing ground to specified standard density tests will be carried out and a Request for
Approval to start filling will be submitted. Where it is the intention to commence filling will
be commence by cutting to firm material, for cross fill.
Fill materials for use in forming embankments shall be suitable material obtained from
excavation cuttings or borrow pits.
Prior to commencement of the works, the selected sample from the source of cutting or
borrow pits shall be sent for laboratory test.
Trial compaction shall be carried out at the designated area of the site to determine the
pattern of compaction for type of material to be used. This shall include the use of
compaction plant and the number of passes in relation to the loose depth of material to
achieve desired compaction. The approximate quantity of water required per unit area to
bring the fill close enough to the Optimum Moisture Content to achieve the specified
compaction standard economically shall be computed and thereafter uniformly mixed
throughout the material depth and width to be compacted.
After the required passes for compaction has been accepted, the filling shall be carried out
in layer not exceeding 200 mm compacted depth and shall be compacted by the compaction
plant as used and achieved in the trial areas.
The density test shall be carried out in every compacted layer of approx. 200 mm depth and
the Nos. of test shall be done in accordance with the MORT&H specification.
The Engineers Site representative will witness the test and the result sent to the Engineer
for approval to proceed further with next layer.
On the fill slope, the filling shall be in layer and with extended extra width for cut back to
form the compacted slope.
Prior to the commencement of massive cut/fill, the haul roads shall be constructed with
sufficient width for to and fro traffic and to ensure smooth movement of the plant.
Excavators shall be deployed for excavation and loading the cut material on the dump trucks
for filling. At the filling area, the dump trucks transport the material to the spread spot and
tip from one end. One bulldozer or grader shall be used for spreading the material into loose
layers to the thickness indicated by the compacted thickness or less. Water shall be spread
and mixed in as required until the whole layer is of one uniform moisture content and the
vibrating roller shall be used for compacting the layer. Field Density tests shall carry out,
and if the results indicate compliance with the specification then a Request for Approval to
place the next layer will be submitted.
The slope trimming shall be completed after the pavement and shoulders are completed.
The trimmed slope is to be turned, if specified.
Subsoil drain:
General:
This work shall include the supply and installation of subsoil drains constructed in
accordance with the contract specification at the locations and in accordance with the lines,
levels and grades as shown on the drawings and or as directed by the Engineer.
Materials:
CONCRETE PIPES OR Polyvinyl chloride (PVC) pipes for the subsoil drains shall comply
with the relevant contract specification.
Filter material used in the construction of subsoil drains shall consist of hard, clean, crushed
rock or gravel having a grading limits given in the specification. The aggregate crushing
value of the material shall not exceed 30%.
Construction method:
Excavation of longitudinal and cross trenches shall be carried out all in accordance with the
approximate provisions of specification and drawings. At the completion of excavation,
Request for Approval forms for placing filter materials will be submitted to the Engineer.
Filter cloth shall then be placed to cover the perimeter of the longitudinal trench excavated,
with the top open to facilitate the placement of filter material. Subsoil cross pipe is then laid
in the cross trench at minimum 1% slope, with the inlet face covered with filter cloth and
the outlet being free outfall. The inlet of cross pipe is to be imbedded in the filter material
fill placed in the longitudinal trench. Care shall be taken against damage of filter cloth
during the construction stage.
Filter material shall be placed in longitudinal trench and uniformly compacted. The filter
cloth shall be closed at top and backfilled with soil. At the completion of placing filter
materials a Request for Approval for placing compacted backfill will be submitted. During
backfilling random field density check tests will be carried out.
Granular sub-base:
General:
Sub base is the lowest of all the pavement layers consisting of natural sand, mooram, gravel,
crushed stone or combination thereof necessary to comply with the grading requirements of
Table 400-1 Grading I.
Materials:
Prior to the laying of sub base, a Request for Approval of Material shall be submitted which
will indicate compliance with the specified properties of sub base material.
a) Fraction of material passing the 22.4 mm sieve shall have a soaked CBR of 30% or
greater.
b) The fraction passing the 0.425 mm sieve shall have Liquid Limit not greater than 25
and a Plasticity Index not greater than 6.
c) The soaked 10% fines value (KN) shall be greater than 50.
d) If the water absorption is greater than 2% the Soundness Test IS 383 shall be carried
out.
The grading shall be as follows:
SEIVE SIZE (MM)
PERCENTAGE PASSING
75
100
53
80-100
26.5
55-90
9.5
35-65
4.75
25-55
2.36
20-40
0.425
10-25
0.075
3-10
Laying equipment:
The following plants are required for the laying of sub-base:i.
Motor Grader
ii.
Tipper Trucks
iii.
Vibratory Roller
iv.
Water Tanker
Wet mix macadam (WMM) is a base material in road pavement structure, which is batched
from a mixing plant, and laid in position with a paver.
Materials:
WMM consists of crushed graded aggregate and granular material pre mixed with water.
Equipments:
Constructional plants required are as follows:NO. OF UNIT/TEAM
A)
B)
PAVER
C)
MOTOR GRADER
D)
VIBRATORY ROLLER
E)
TIPPER
Procedures:
Work shall commence on site upon Approval and Acceptance of the sub-base layer.
The wet mix macadam shall be plant mixed with moisture content within reasonable limits
of the Optimum Moisture Value, as determined in accordance with IS 2720 (Part 8).
The approved wet mix macadam shall be delivered to site by tipper trucks. To prevent the
loss of moisture, the materials shall be covered, if necessary.
i.
ii.
Segregation at localized areas shall be made good by back casting with fines or by
immediate removal and replacement of the freshly laid wet mix macadam.
iii.
Transverse joint shall be lapped and longitudinal joints due to stoppage of work will
have the loose removed before paving resumes.
iv.
Compaction shall be carried out using vibratory roller and as per specifications.
v.
The surface of the wet mix macadam shall be finished to the grade and line as
required by the drawings, and within specified tolerance limits.
vi.
vii.
Materials:
DBM consists of the following materials:
i.
Road base material complying with IS:2386 (Part- 1,3,4,5) and IS:2720 (Part 37) and
table 500-8 of the MOST specification and the grading shall be within the range
shown below and the design mix shall be approved from the Engineer.
ii.
The plasticity index of the fraction passing the 425-micron sieve should not exceed
4.
iii.
Bitumen (6-/70) penetration grade. The quantity will be as specified in the contract
and bitumen 4.0 percent.
iv.
v.
Temperature of materials.
vi.
The aggregates shall be surface dry and shall be mixed at 155o C to 163oC
temperature with binder temperature at 150o C to 163o C. the mixed material as
delivered to the laying site shall be between 120oC to 160o C.
Mixing:
The materials including any added filler, shall be weighed or measured into a mechanical
mixer and thoroughly mixed in such a manner that all particulars of the aggregate are
completely and uniformly coated.
Equipments:
Plant required to produce DBM:
i.
Premix Plant
ii.
Wheel Loader
Tipper Trucks
ii.
Asphalt Paver
iii.
iv.
Bitumen Sprayer
Procedure:
Work shall commence on site upon approval and acceptance of the wet mix macadam and
prime coating. Tack coat shall be sprayed on the surface, to receive the DBM.
The dense bituminous macadam shall be plant mixed as specified in design mix.
The approved DBM mix shall be delivered to site by tipper trucks. To prevent the loss of
heat, the mixture shall be covered.
The dense bituminous macadam shall be laid by paver in 50 to 100mm layer as specified in
the contract.
If the laid surface is open-textured, back casting shall be carried out and the bigger size
aggregates removed before rolling.
At the end of the paving operation, the transverse joint shall be feathered down. Lap joint
shall be provided for the next operation of paving.
Compaction shall be carried out using the specified/ equivalent type of compactors and for
rolling pattern shall be as per specifications.
Rolling shall always commence from the lower to the higher side of the carriageway. The
minimum rolling temperature shall be 100oC.
The surface of the dense bituminous macadam shall be finished to the grade and line as
required by the drawings, within the specified tolerance limits of +6 mm.
On completion of laying and compaction, checks shall be carried out to verify compliance
with the specified requirements.
Equipments:
Plant required to produce WC shall be:
i.
ii.
Wheel loader
Tipper Trucks
ii.
Asphalt Paver
iii.
Tandem Roller
iv.
Bitumen Sprayer
Procedures:
Trial mix and trial lay shall be carried out to assess the suitability of the mixing, laying and
compacting plant and to establish the sequence of the laying operation.
Works shall commence on site upon approval and acceptance of the asphalt concrete wearing
course.
The surface to receive the Asphalt concrete wearing course shall be freed of all dirt, loose
materials and standing water.
Tack coat of approved bitumen emulsion or cut back shall be applied as per the specifications on
the prepared surface prior to laying of the asphaltic concrete wearing course.
The ACWC shall be plant mixed with bitumen content as established in the Job Standard
Mixture.
The approved asphaltic concrete mixture shall be delivered to site by tipper trucks. To prevent
the loss of heat, the mixture shall be covered if necessary.
The ACWC shall be laid in single layer.
If the said surface is open textured, back casting shall be carried out and the bigger size
aggregates removed before rolling.
At the end of paving operation, the transverse joint shall be feathered down. Vertical joint shall
be provided for the next operation of paving.
Compaction shall be carried out using the specified/equivalent type of compactors and the rolling
pattern shall be as agreed with the Engineer. In our project, every layer was compacted six times,
with first and last compaction, plain and middle four compactions, with vibrations.
Rolling shall always commence from the lower end to the higher side of the carriageway. The
minimum rolling temperature shall be 100 degree Celsius.
The surface of the ACWC shall be finished to the grade and line as required to the drawings
within the tolerance limits.
On completion of laying and compaction, checks shall be carried out to verify compliance with
the specified requirements.
Materials:
All the materials required in the construction will be from the source approved by the
Engineer and according to the relevant clauses of MORT&H specifications mentioned in the
contract.
Cement
601.2.2
Coarse aggregates
602.2.4.2
Fine Aggregates
602.2.4.2
Water
601.2.4
Aggregate gradation given in table 600-1 of MORT&H specifications shall be adopted after
blending the coarse and fine aggregates.
Sieve Designation
% passing Proposed by %
passing
Weight
Weight
26.50 mm
100
100
19.00 mm
87.4
80-100
9.50 mm
67.6
55-76
4.75 mm
46.1
35-60
600.00 Micron
18.2
10-35
75.00 Micron
5.4
0-8
Limits
by
Aggregates are fed into the cold bins from online storage bins of a 4-stage crusher or from
the approved stacks. Cement is obtained either in bags or bulk and necessary support system
will be employed for feeding the 120-140 MT storage silos of the concrete batching plant.
Mix for dry lean concrete will be appropriately proportioned to achieve the strength
requirements mentioned in the specifications and prior approval shall be taken from the
engineer before adopting for the site trials.
The calibration trial of the batching plant will be undertaken with the approved proportions
after the calibration of the plant. The approved mix will then be used on the trail length
already identified jointly by the representatives of the contractor and the engineer.
Equipment:
The following plants and equipment will be deployed for the construction of DLC:
i.
Concrete batching plant (200 Cum/hr) with all the required accessories and storage
facilities.
ii.
Tippers
iii.
Sensor Paver
iv.
Excavator/JCB
v.
Vibratory Roller
vi.
Water Tankers
vii.
Preparation:
i.
The GSB surface already approved will be given a fine sprayed with water and rolled
with the earth compactor giving a couple of passes after a lapse of 2-3 hours of
watering. This will stabilize the loose surface. Prior to watering, loose or dislocated
spots, if any, will be identified and they will be rectified by removing loose material
and back filling with appropriate material and compacting to the required degree of
compaction as the adjoining areas. The GSB surface will be kept ready at least one
day in advance of DLC laying.
ii.
Before start of laying, it will be ensured that the guide/sensor wires are in position on
both sides or on one side of the Paver depending upon the paver pressed used for the
work. For SP1600, guide wires will be provided on both sides of the paver. For
normal sensor pavers, guide wires will be provided on one side with slope control
provision. There will be designated entry points for the trucks carrying concrete on
to the new carriageway or prepared GSB layer.
Paving:
i.
Paving is kept in position and the concrete is dumped in hopper in case of normal
sensor paver and paving is done by spreading a loose thickness of about 200 mm for
achieving the compacted thickness of 150 mm. the loose thickness is ascertained by
conducting trial laying of DLC. The paving will be done on the same day matching
with the first lane.
ii.
In case of use of SP 1600, the DLC is laid to full width with guide wires fixed on
both sides relative to the line and grade and cross- slope as per the drawings. The
concrete is dumped in front of the paver and it is spread across the width by the
spreader.
iii.
It will be ensured that traverse and longitudinal construction joints are staggered by
500-1000 mm and 200-400 mm respectively from the corresponding joints in the
overlaying pavement quality concrete.
Transporting:
The concrete is transported in tippers from the batching plant and to the place of laying. The
tippers are covered with tarpaulins in order to prevent water loss due to evaporation during
transit. It will be ensured that there will be sufficient number of tippers for uninterrupted
supply of material to the paving equipment.
Compaction:
The compaction is carried out immediately after the material is laid and leveled. Rolling
shall be continued on full width till there is no further visible movement under the roller and
surface is compact. The required compaction effort in terms of number of passes is
ascertained by employing one single drum smooth wheeled vibratory roller and one double
drum smooth wheeled vibratory roller on the trail stretch of DLC. After arriving at the
efficiency of the proposed set up in the trial length, depending upon the programmed
quantity and period of laying, additional rollers will be deployed. Initial two passes will be
plain passes on order to roll down the loose DLC. Then vibratory pass will be given
followed by plain passes for providing a finished and closed surface.
Curing:
Curing of the DLC will be done by covering the surface by gunny bags or hessian cloth,
which will be kept continuously moist for seven days by sprinkling water using water
tankers.
Testing:
After the construction of the trial length, the in-situ density of freshly laid material will be
determined by sand replacement method with 20 cm diameter density cone. The density will
be taken at three location along the diagonal that bisects the trail length. The locations for
testing will be at least 50 cm from the edges. The average density of three holes will be
considered as 100% and the field density of regular work will be compared with this
reference density in accordance with clauses 601.5.5.1 and 903.5.1.2 of MORT&H
specifications. Course will be cut to check segregation or any other deficiency. The routine
quality control tests for levels alignment and material will be exercised as per the frequency
norms given in table 900-6. Other tests will be done at the frequency mentioned therein. If
there could be any reduction in total number tests depending upon the consistency of the
results, ration will be taken up with the Engineer.
Description
Frequency
Testing of cubes
Each 100 sqm or part there of laid each day from the uncompacted material
In-situ density
Thickness
Cores at random
Repairs:
Rectification, if any will be taken up before overlaying PQC. The low spots, loose material,
pot holes etc will be made good by using fresh lean concrete material duly compacting the
same as per specifications. For repairing honey combed surface, and any other spots which
cannot be repaired with DLC material, concrete with aggregates of size 10mm and below
will be used after roughening the surface for proper keying in.
Compaction of soils:
The road crust is founded on sub grade and any deficiencies in the stability of earthwork results
in settlements and other distress develop in pavement during service under traffic. Therefore
good stability is necessary for the sub grade. Proper compaction at appropriate moisture is the
most effective and economical way to improve the stability of soils.The density test is the
principal means by which the engineer determines whether or not the specified compaction
requirements have been met.
For a given compaction effect as the moisture content is changed density of soil varies and
maximum density is achieved at optimum moisture. Soil is compacted in proctors apparatus
and dry weight is assessed for different moisture contents. The results are plotted and the
maximum dry weight is the highest point of the curve and is called proctors density of soil.
Type of work
The size of the coarse material in the mixture of earth shall ordinary not exceed 75mm when
being placed in the embankment and 50mm when placed in the sub grade.
The soil for embankment and sub grade must be tested for compaction requirements.
Type of work/material
Relative compaction as % of
maximum lab dry density as per is
2720
Embankment
Expansive soils
a> Sub grade and 500mm portion just
below the sub grade.
Not allowed
Clayey soils if any should be removed and replaced by good granular soil.
The embankment and sub grade material shall be spread in layers of uniform thickness not
exceeding 200 mm compacted thicknesses over the entire width of embankment. Successive
layers shall not be placed until the layer under construction has been thoroughly compacted to
the specified requirements. Moisture content of each layer of soil is checked in accordance with
IS-2720.
Load carrying capacity of soil is measured from penetration resistance i.e. test conducted on
compacted specimen and expressed as per percentage of a standard crushed rocks specimen and
called as CBR of Soil.
CBR 100 Percent (viz) Load of 1360 kg to drive cylindrical plunger of 19.30 sqcms to a distance
of 0.250 mm at the rate of 0.125 mm per minute.
Type of Soils
CBR
20-90
10-40
15-40
5-15
3-8
exceed 5 kms per hour. Rolling shall be continued till the density achieved is at least 98% of the
maximum dry density for the material as per IS 2720 (Part 8).
Road aggregates: These have to bear the stresses due to the wheel loads and hence they
should possess sufficient strength to resist crushing. They should be hard enough to resist wear
due to abrasive action of traffic. The aggregates in the pavement are also subjected to impact
hence toughness is another desirable property of aggregates. The stones used should be durable
and resist disintegration due to action of weather, this property is called soundness. The
following are the most commonly available rocks in India from which road aggregates can be
obtained.
Type of Rock
Basalt
Properties
Hard and durable, resistant to
Suitability
Good for base courses
Limestone
Sand Stone
40 percent (Maximum)
Or
Aggregate impact value
30 percent (Maximum)
30 percent (Maximum)
Grading requirements: The WBM is carried out in layers. The coarse aggregates for each layer
should confirm to any of (3) grading below. The use of grading no 1 shall be restricted to sub
base courses only.
Size and grading requirements of coarse aggregates for water bound macadam.
Grading No.
Thickness and
aggregate per
10 sqm.
Size range
IS sieve
Percent by
designation
weight passing
the sieve
10 mm
125 mm
100
1.21 to 1.13
90 mm
90-100
cums.
63 mm
25-60
45 mm
0-15
22.4 mm
0-5
90 mm
100
0.91 to 1.01
63 mm
90-100
cums.
53 mm
25-70
45 mm
0-15
22.4 mm
0-5
75 mm
90 mm to 45 mm
63 mm to 45 mm
75 mm
53 mm to 22.4
63 mm
100
0.91 to 1.07
mm
53 mm
95-100
45 mm
65-90
22.4 mm
0-10
11.2 mm
0-5
cums.
The compacted thickness for a layer with grading no 1 shall be 100 mm while for layer with
other grading i.e. 2&3 shall be 75 mm.
Application of screenings:
To fill voids in the coarse aggregates, screenings are generally necessary and shall consist if the
same material as the coarse aggregate.
As far as possible, the screening material should conform to grading given in the table.
Grading
Size of screening
IS sieve designation
classification
A
Percent by weight
passing the sieve
13.2 mm
11.2 mm
13.2 mm
100
11.2 mm
95-100
5.6 mm
15-35
180 microns
0-10
11.2 mm
100
5.6 mm
90-100
180 microns
15-35
Gravel:
Non-Plastic material such as moorum or gravel may also be used for filling the voids in the
coarse aggregates provided liquid limit and plasticity index of such material are below 20 and 6
respectively and fraction passing 75 microns sieve doesnt exceed 10%.
Construction operations:
The coarse aggregates shall be spread uniformly and evenly upon the prepared sub grade/sub
base/base to proper profile by using templates placed at 6 mts apart and all high or low spots
remedied by removing or adding aggregates. Immediately after spreading of coarse aggregates
rolling shall be started with power roller of 8 to 10 tons of capacity or vibration roller of 8 to 10
tons weight. First the edge shall be compacted and move inward parallel to the centre line of the
road duly lapping preceding tracks by at least one half width. Rolling is continued until the
aggregates are well compacted and no waveform is seen when the roller is advancing. Screening
shall be applied gradually brooming and dry rolling is continued until no more screenings be
forced into voids of the coarse aggregates. All this operations shall be carried out in only such
lengths of road, which could be completed within one day. Now the surface be copiously
sprinkled with water, wet screenings swept and rolled until the coarse aggregates has been
thoroughly keyed well bonded and firmly set in its full depth. The binding material shall be
applied successively in 2 or more thin layers and the surface shall be copiously sprinkled with
water, the resulting slurry swept in with brooms to fill the voids. The rolling shall be continued
until the resulting slurry after filling voids forms a wave ahead of wheels of the moving roller.
After final compaction the pavement shall be allowed to dry over night and no traffic is allowed
for 2 or 3 days until the macadam has set. The roads shall be kept watered so that it remains in
damp condition under traffic for about a fortnight.
% by weight passing
53mm
100
45mm
95-100
22.4mm
60-80
11.2mm
40-60
4.75mm
25-40
2.36mm
15-30
600 micron
8-22
75 micron
0-8
The mix shall be spread uniformly using a paver finishers or motor grader and no segregation of
larger and finer particles be allowed. While constructing WMM confinement of mix against
lateral movement shall be ensured by simultaneous shoulder development. Traffic shall not be
allowed until the mix has dried at least for 24 hours.
Bituminous pavement:
Pavement made of aggregates and bitumen as binding material are smooth, dust free and have
higher load carrying capacity and longer life period of 10 to 15 years; hence most of the roads
are being constructed/converted to black top.
Bituminous material:
Bitumen is a viscous liquid, semisolid or solid material, colour varying from black to dark brown
having adhesive properties consisting essentially hydrocarbons is derived from distillation of
petroleum crude or natural asphalt and soluble in carbon disulphide. Bituminous materials used
for paving purposes are penetration grade bitumen and liquid bitumen (cutbacks & emulsion).
The bituminous binder should possess the following qualities.
Adequate viscosity at the time of mixing and compaction.
Not highly temperature susceptible.
Should not strip from aggregate in presence of water.
The following suitability tests are followed.
Consistency test:
Penetration test
Viscosity test
Softening point test
Ductility test
Compaction test:
Loss on heat test
Solubility test
Water content test
Distillation test
Spot test
Specific gravity test:
Varies from 1.00 to 1.28
Flash and fire point test:
Safety test to indicate the max temperature to which the bituminous material can be safely
heated.
Measurement of penetration a 100 gm standard steel needle into a bitumen binder kept into a
bitumen binder kept at 25 degrees within 5 sec is known as penetration value.
Viscosity is its important physical property low viscous binder may flow off the aggregate during
transit from mixing plant to site and a high viscous material may provide an unworkable mix.
Viscometer is used to measure the viscosity of the bitumen.
The ductility of a bituminous material is measured by the distance in centimeters to which it will
elongate before breaking when a briquette specimen of the material of the form is pulled apart at
a specified speed (50 mm/min) and specified temperature of 27 degrees- bituminous briquette is
subjected to rupture in the testing machine.
Softening point: The temperature at which the bitumen attains the particular degree of softening
under specified condition of test- measured with ring and ball apparatus.
Flash point: It is the lowest temperature at which the vapour of bitumen momentarily takes fire
in the form of a flash under specified condition of test- pensky-martens tester is the apparatus
used to test flash point.
Fire point: It is the lowest temperature at which the material gets ignited and burns under
specified condition of test- measured with pensky-martens tester.
1.12-1.28
0.50
175
45-60
Penetration at 25 degrees
80-100
Ductility at 24 degrees
75
The aggregates used in bituminous works shall satisfy the following physical requirements.
Property
Test
Specification
Cleanliness (Dust)
Particle shape
Max 30%
index
Strength
Durability
Max 35%
Max 27%
Soundness
Sodium sulphate
Max 12%
Magnesium sulphate
Max 18%
Water absorption
Water absorption
Max 2%
Stripping
Bituminous courses:
Bituminous courses of different specifications are laid on WBM/WMM base or existing BT
surface. A PRIME COAT over macadam base at the rate of 6 to 9 kgs/10 sqms and TACK
COAT of 2 to 3 kgs/sqms over existing BT surface shall precede the bituminous courses. The
specification for different classes of BT work varies with respect to size of aggregates and
quantity of bitumen used. The voids in bituminous surface will be sealed by application of seal
coat.
Item of
Grade
work
Premix
Thickness
Nominal
Bitumen
Ref to
of layer in
aggregate
content %
MOST
mm
size
by weight
specification
20 mm
12 mm
2.8
511
Grade 1
80-100
40 mm
3.1 to 3.4
504
Grade 2
50-75
19mm
3.3 to 3.5
504
Grade 1
80-100
40mm
4.0
507
macadam
Grade 2
50-75
25mm
4.5
507
Semi dense
Grade 1
35-40
13 mm
4.5
508
concrete
Grade 2
25-30
10mm
5.0
508
Bituminous
Grade 1
50-65
19 mm
5 to 6
509
Grade 2
30-45
13 mm
5 to 7
509
carpet
2
Bituminous
macadam
Dense
bituminous
bituminous
concrete
Apart from conformity with grading and quality requirements individual ingredients the mix
shall meet the requirements of Marshall test.
Minimum stability(kg at 60 degree centigrade)
820 kgs
Flow (mm)
2-4
3-5
8-22
Aggregate blending:
The aggregates from the crusher are stored in BINS. For getting the desired mix three or four
aggregates have to be mixed and proper proportioning of different aggregates is called aggregate
blending.
The following table illustrates aggregates blending of DBM.
Sieves
37.5
26.5
12.5
4.75
2.36
0.3
0.075
90
56
29
19
MOST
Max
100
100
80
59
45
17
MOST
95
68
44
32
11
Designed 100
93.2
66.2
48
31.3
8.9
2.1
Blending
Bin- A
100
65.9
.6
.5
.4
.3
.2
20
Bin-B
100
100
33.5
.9
.7
.4
21
Bin-C
100
100
100
61.2
9.7
2.9
1.3
29
Bin-D
100
100
100
100
94.1
26.1
5.5
30
Pass
100
.
of minimum 60 meters length shall be constructed and dry density of the mix shall be determined
to be used as reference density.
CBR: The ratio of the force per unit area required to penetrate a soil mass with a plunger of
50mm diameter at the rate of 1.25mm/minute to the required corresponding penetration of
standard material.
Generally the ratio is determined for 2.5mm and 5.0mm penetrations, and where the ratio at
5.00mm is consistently higher than that at 2.5mm, the ratio at 5.00mm is considered.
Apparatus: Cylindrical mould , metal rammer, spacer disc, metal weights, perforated base
plate, metal tripod stand, penetration plunger, loading machine with moving head, sieves,
balances, oven , air tight container, tray, trowel, measuring jar.
Procedure:
i.
Take a representative sample to be tested, pour it in the form of a heap and divide into 4
equal parts by quartering method and mix the material in one of the two diagonals and
sieve it through 19mm sieve, the material retained shall be replaced by the equal amount
of passing through 19mm sieve, but retained on 4.75mm sieve, obtained from the material
of the other two diagonals, so that the passing material shall weigh a minimum of 5500gm.
ii.
Place it in a tray and mix with the equal amount of that water required obtaining OMC.
iii.
Note the empty weight of the cylindrical mould to the nearest 1 gm.
iv.
v.
Make the water mixed soil into 5 equal parts, place the spacer disc in the mould and a
filter paper and place one part into the mould fitted with collar.
vi.
Compact the soil with the metal hammer by distributing the 55 blows equally on the
surface of the soil.
vii.
Continue this process till the fourth layer, make an impression on the fourth layer of the
compacted soil to a depth of 25mm, so that the next layer will plug into this and avoid
separation of the top layer from the previous while removing the collar.
viii.
ix.
Add fifth layer and compact it with metal hammer by giving 55 blows.
Remove the collar and also remove the excess soil up to the level exactly equal to the
cylindrical mould by using trowel or spatula. Note the weight of the sample with the
mould to the nearest 1 gm.
x.
Reverse the compacted mould, tighten the mould on the base plate, place the perforated
disc with surcharge weights of 5kg on the compacted soil specimen with the mould and
soak it in water for 96hours. Maintain constant water level in the tank throughout the
soaking period.
xi.
After the soaking period, take out the mould with the soil specimen from the water tank
and allow it to drain free water collected in the mould, downward for 15 minutes.
Procedure:
i.
The soil sample received from the field shall be dried in the oven at 105 to 110 degree
centigrade.
ii.
The oven dried sample shall be taken by quartering method to have a minimum weight.
iii.
The mass of the sample taken for testing shall be weighed to nearest 0.1gm.
iv.
Pour water in the sample with water tight tray and leave it for 2hrs.
v.
Wash the sample under water by allowing the washed water to go through the lowest size of
sieve.
vi.
Wash bigger size aggregate first by rubbing in between two hands, ensure that the 75 microns
sieve never gets overloaded, since it may get damaged.
vii.
Wash the sample till the water passing the sieve is substantially clean, collect all the material
retained on 75 microns, drain out the excess water and keep it in oven for 24hrs at 105 to 110
degree centigrade.
viii.
Allow the sample to cool, and perform dry sieving with the largest size of sieve first and the
next sizes consecutively.
ix.
Ensure that the sieving is complete, and the amount of material retained on each sieve shall
be weighed and noted.
x.
The cumulative mass of the soil fraction shall be then calculated, and percentage of passing
on each sieve shall then be reported.
xi.
The material passing 100mm sieve and retains on 75mm sieve is called Cobble.
xii.
The material passing 75mm sieve and retains on 4.75mm sieve is called Gravel.
xiii.
The material passing 4.75mm sieve and retains on 75 microns is called Sand.
xiv.
ii)
Oven
iii)
iv)
Take two specimens of 10g each of pulverized soil passing through 425m IS Sieve and
oven-dry.
ii.
Pour each soil specimen into a graduated glass cylinder of 100ml capacity.
iii.
Pour distilled water in one and kerosene oil in the other cylinder upto 100ml mark.
iv.
v.
Allow the suspension to attain the state of equilibrium (for not less than 24hours).
vi.
Reporting of results:
Free swell index = [Vd - Vk] / Vk x 100%
Where,
Vd = volume of soil specimen read from the graduated cylinder containing distilled water.
Vk = volume of soil specimen read from the graduated cylinder containing kerosene.
i.
Cylindrical metal mould it should be either of 100mm dia. and 1000cc volume or
150mm dia. and 2250cc volume and should conform to IS: 10074 1982.
ii.
Balances one of 10kg capacity, sensitive to 1g and the other of 200g capacity, sensitive
to 0.01g
iii.
iv.
v.
Preparation of sample:
A representative portion of air-dried soil material, large enough to provide about 6kg of material
passing through a 19mm IS Sieve (for soils not susceptible to crushing during compaction) or
about 15kg of material passing through a 19mm IS Sieve (for soils susceptible to crushing during
compaction), should be taken. This portion should be sieved through a 19mm IS Sieve and the
coarse fraction rejected after its proportion of the total sample has been recorded. Aggregations
of particles should be broken down so that if the sample was sieved through a 4.75mm IS Sieve,
only separated individual particles would be retained.
Procedure to determine the maximum dry density and the optimum moisture
content of soil:
A 5kg sample of air-dried soil passing through the 19mm IS Sieve should be taken. The
sample should be mixed thoroughly with a suitable amount of water depending on the
soil type (for sandy and gravelly soil 3 to 5% and for cohesive soil 12 to 16% below
the plastic limit). The soil sample should be stored in a sealed container for a minimum
period of 16hrs.
ii.
The mould of 1000cc capacity with base plate attached should be weighed to the nearest
1g (W1). The mould should be placed on a solid base, such as a concrete floor or plinth
and the moist soil should be compacted into the mould, with the extension attached, in
five layers of approximately equal mass, each layer being given 25 blows from the 4.9kg
rammer dropped from a height of 450mm above the soil. The blows should be distributed
uniformly over the surface of each layer. The amount of soil used should be sufficient to
fill the mould, leaving not more than about 6mm to be struck off when the extension is
removed. The extension should be removed and the compacted soil should be leveled off
carefully to the top of the mould by means of the straight edge. The mould and soil
should then be weighed to the nearest gram (W2).
iii.
The compacted soil specimen should be removed from the mould and placed onto the
mixing tray. The water content (w) of a representative sample of the specimen should be
determined.
iv.
The remaining soil specimen should be broken up, rubbed through 19mm IS Sieve and
then mixed with the remaining original sample. Suitable increments of water should be
added successively and mixed into the sample, and the above operations i.e. ii) to iv)
should be repeated for each increment of water added. The total number of
determinations made should be at least five and the moisture contents should be such that
the optimum moisture content at which the maximum dry density occurs,
lies within that range.
Reporting of results:
Bulk density Y(gamma) in g/cc of each compacted specimen should be
calculated from the equation,
Y(gamma) = (W2-W1)/ V
where, V = volume in cc of the mould.
The dry density Yd in g/cc
Yd = 100Y/(100+w)
The dry densities, Yd obtained in a series of determinations should be plotted against the
corresponding moisture contents. A smooth curve should be drawn through the resulting points
and the position of the maximum on the curve should be determined.
A sample graph is shown below:
The dry density in g/cc corresponding to the maximum point on the moisture content/dry density
curve should be reported as the maximum dry density to the nearest 0.01. The percentage
moisture content corresponding to the maximum dry density on the moisture content/dry density
curve should be reported as the optimum moisture content and quoted to the nearest 0.2 for
values below 5 percent, to the nearest 0.5 for values from 5 to 10 percent and to the nearest
whole number for values exceeding 10 percent.
Take about 8g of the soil and roll it with fingers on a glass plate. The rate of rolling
should be between 80 to 90 strokes per minute to form a 3mm dia.
ii.
If the dia. of the threads can be reduced to less than 3mm, without any cracks appearing,
it means that the water content is more than its plastic limit. Knead the soil to reduce the
water content and roll it into a thread again.
iii.
Repeat the process of alternate rolling and kneading until the thread crumbles.
iv.
Collect and keep the pieces of crumbled soil thread in the container used to determine the
moisture content.
v.
Repeat the process at least twice more with fresh samples of plastic soil each time.
Reporting of results:
The plastic limit should be determined for at least three portions of the soil passing through
425m IS Sieve. The average water content to the nearest whole number should be reported.
This test is done to determine the liquid limit of soil as per IS: 2720 (Part 5) 1985. The liquid
limit of fine-grained soil is the water content at which soil behaves practically like a liquid, but
has small shear strength. Its flow closes the groove in just 25 blows in Casagrandes liquid limit
device. The apparatus used :i.
ii.
iii.
Oven
iv.
Evaporating dish
v.
Spatula.
vi.
vii.
viii.
Wash bottle.
ix.
Preparation of sample:
i) Air-dry the soil sample and break the clods. Remove the organic matter like tree roots, pieces
of bark, etc.
ii) About 100g of the specimen passing through 425m IS Sieve is mixed thoroughly with
distilled water in the evaporating dish and left for 24hrs for soaking.
Place a portion of the paste in the cup of the liquid limit device.
ii.
iii.
Draw the grooving tool through the sample along the symmetrical axis of the cup,
holding the tool perpendicular to the cup.
iv.
For normal fine grained soil: The Casagrandes tool is used to cut a groove 2mm wide at
the bottom, 11mm wide at the top and 8mm deep.
v.
For sandy soil: The ASTM tool is used to cut a groove 2mm wide at the bottom, 13.6mm
wide at the top and 10mm deep.
vi.
After the soil pat has been cut by a proper grooving tool, the handle is rotated at the rate
of about 2 revolutions per second and the no. of blows counted, till the two parts of the
soil sample come into contact for about 10mm length.
vii.
Take about 10g of soil near the closed groove and determine its water content.
viii.
The soil of the cup is transferred to the dish containing the soil paste and mixed
thoroughly after adding a little more water. Repeat the test.
ix.
By altering the water content of the soil and repeating the foregoing operations, obtain at
least 5 readings in the range of 15 to 35 blows. Dont mix dry soil to change its
consistency.
x.
Liquid limit is determined by plotting a flow curve on a semi-log graph, with no. of
blows as abscissa (log scale) and the water content as ordinate and drawing the best
straight line through the plotted points.
Reporting of Results:
Report the water content corresponding to 25 blows, read from the flow curve as the liquid
limit.
ii.
Apparatus:
The apparatus for the shape tests consists of the following:
i.
ii.
iii.
IS sieves of sizes 63, 50 40, 31.5, 25, 20, 16, 12.5,10 and 6.3mm.
iv.
Theory:
The particle shape of aggregates is determined by the percentages of flaky and elongated
particles contained in it. For base course and construction of bituminous and cement concrete
types, the presence of flaky and elongated particles are considered undesirable as these cause
inherent weakness with possibilities of breaking down under heavy loads. Thus, evaluation of
shape of the particles, particularly with reference to flakiness and elongation is necessary. The
Flakiness index of aggregates is the percentage by weight of particles whose least dimension
(thickness) is less than three- fifths (0.6times) of their mean dimension. This test is not
applicable to sizes smaller than 6.3mm. The Elongation index of an aggregate is the percentage
by weight of particles whose greatest dimension (length) is greater than nine-fifths (1.8times)
their mean dimension. This test is not applicable for sizes smaller than 6.3mm.
Procedure:
i.
Sieve the sample through the IS sieves (as specified in the table).
ii.
Take a minimum of 200 pieces of each fraction to be tested and weigh them.
iii.
In order to separate the flaky materials, gauge each fraction for thickness on a thickness
gauge. The width of the slot used should be of the dimensions specified in column (4) of
the table for the appropriate size of the material.
iv.
Weigh the flaky material passing the gauge to an accuracy of at least 0.1 per cent of the
test sample.
v.
In order to separate the elongated materials, gauge each fraction for length on a length
gauge. The width of the slot used should be of the dimensions specified in column (6) of
the table for the appropriate size of the material.
vi.
Weigh the elongated material retained on the gauge to an accuracy of at least 0.1 per cent
of the test sample.
Observations:
Flakiness Index
Elongation Index =
Result:
i.
Flakiness Index
ii.
Elongation Index =
ii.
iii.
iv.
A tamping rod of 10mm circular cross section and 230mm length, rounded at one end and
Oven.
Preparation of sample:
i.
ii.
The sample should be oven-dried for 4hrs. at a temperature of 100 to 110oC and cooled.
iii.
The measure should be about one-third full with the prepared aggregates and tamped with
25 strokes of the tamping rod.
A further similar quantity of aggregates should be added and a further tamping of 25 strokes
given. The measure should finally be filled to overflow, tamped 25 times and the surplus
aggregates struck off, using a tamping rod as a straight edge. The net weight of the aggregates in
the measure should be determined to the nearest gram (Weight A).
The cup of the impact testing machine should be fixed firmly in position on the base of
the machine and the whole of the test sample placed in it and compacted by 25 strokes of
the tamping rod.
ii.
The hammer should be raised to 380mm above the upper surface of the aggregates in the
cup and allowed to fall freely onto the aggregates. The test sample should be subjected to
a total of 15 such blows, each being delivered at an interval of not less than one second.
Reporting of results:
i.
The sample should be removed and sieved through a 2.36mm IS Sieve. The fraction
passing through should be weighed (Weight B). The fraction retained on the sieve
should also be weighed (Weight C) and if the total weight (B+C) is less than the initial
weight (A) by more than one gram, the result should be discarded and a fresh test done.
ii.
The ratio of the weight of the fines formed to the total sample weight should be expressed
as a percentage.
Two such tests should be carried out and the mean of the results should be reported
This test is done to determine the bitumen content as per ASTM 2172. The apparatus
needed to determine bitumen content are:-Centrifuge extractor.
ii.
iii.
i.
If the mixture is not soft enough to separate with a trowel, place 1000g of it in a large
pan and warm upto 100oC to separate the particles of the mixture uniformly.
ii.
Place the sample (Weight A) in the centrifuge extractor. Cover the sample with
benzene; put the filter paper on it with the cover plate tightly fitted on the bowl.
iii.
Start the centrifuge extractor, revolving slowly and gradually increase the speed until
the solvent ceases to flow from the outlet.
iv.
Allow the centrifuge extractor to stop. Add 200ml benzene and repeat the procedure.
v.
Repeat the procedure at least thrice, so that the extract is clear and not darker than the
light straw colour and record the volume of total extract in the graduated vessel.
vi.
Remove the filter paper from the bowl and dry in the oven at 110 + 5oC. After
24hours, take the weight of the extracted sample (Weight B).
Reporting of results:
i.
ii.
Bibliography:
BSCPLEngineersbook
MORTH
HighwayEngineeringbyS.K.KhannaandC.E.G.Justo
TransportationEngineeringbyL.R.Kadiyali
HighwayMaterialManual[JNTU]