1. 0
A Summer Training Report On Overhead Bridge
Completed by,
U.P. STATE BRIDGE CORPORATION
Ltd.
Project Name
Construction of overhead bridge over existing railway crossing
NO.94-C Hathras Jn. Ladpur Tundla-Ghaziabad rail section (94-C)
Duration
20 June to 30 July, 2016
Submitted by
Ankit Gautam
1334000007
B.Tech- 3rd
Year
Department Of Civil Engineering
Vivekananda College of Technology & Management
ALIGARH (U.P) India -202002
2. 1
Contents
1. Site location
2. Introduction to UPSBC
3. Some important things
4. Acknowledgement
5. Features of project
6. Machines and equipment used
Hydraulic crane
Portable concrete mixer
Auto level
Pre-stressing jacks
Pressure grouting machine
Needle vibrator
7. Component of bridge
Reinforced earth wall panels
Geomats
Geotextile
Pier
Bearing
Bridge deck
Abutment
Pre-stressing
3. 2
Sheathing or ducts
Strands
Pre-stressed concrete
Production of concrete
8. Quality control of concrete
Cube strength of concrete
Aggregate impact value
Sieve analysis
Flakiness and elongation index
Slump cone test
5. 4
About U.P State Bridge Corporation Ltd.
U.P. State Bridge Corporation Ltd. started functioning on 1st
March
1973 as a company under U.P. State Government to accelerate the
activities of design and construction of Bridges in the state.
U.P. State is rich in Geographical and topographical diversities like
small and big rivers, varying terrain all through the state. For the speedy
development of the state it was necessary to connect all part of the state
by roads and bridges. Simultaneously it also required provision of best
technical support for economic & quality execution, commensurate to
Infrastructural facilities in the form of Bridge engineers and technical
staff available in the State. Initially in U.P.P.W.D. departmental
construction units were established for the purpose of Quality and
Speedy construction. With great success the bridge engineers and
technical staff of U.P.P.W.D. were ready to complete the Bridges
departmentally within stipulated time with desired workmanship. This
encouraged the engineers and U.P. Govt. to establish a separate body
for design and construction of bridge and this gave birth to U.P state
bridge corporation (UPSBC).After successful completion of several
bridges, the Board of Director of UPSBC felt that the technical experts
of the State in the field of Bridge Construction & Design should be
utilized in enhancing the similar activities in other States of the country
and abroad. To achieve this UPSBC started competing in tender
process for obtaining the work in open market competition. If proved
to be of great success day by day. Incidentally due to liberalization of
economic environment, the consultants and contractors have come to
occupy a crucial role in Indian economy. They not only provide the
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needed expertise to plan, build and manage the projects within the
country, but also bring the foreign currency from assignments abroad,
besides promoting transfer of technologies more effectively and
providing professional inputs for industrial & technological
developments. Due to the liberalization policy Indian consultants and
contractors need considerable impulse to expand and grow, and realize
its high potential at home and aboard.
The main theme and activities of UPSBC always remain to provide a
strong support in the field of Bridge and highways construction and
Consultancy in design, planning and maintenance which has a large
scope not only in our country but also aboard. UPSBC has successfully
constructed a number of bridges and roads in Iraq, Yemen and Nepal
also in addition to U.P. along with other States of India and earned
reputation and foreign currency for the country. Since UPSBC is a
Govt. undertaking, therefore all the profit earned by UPSBC ultimately
adds to State Govt.
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Some important things!!
Always wear good quality helmet on the site.
Always wear shoes on site.
Wear safety belt, if required.
Safety nets should be provided wherever it is
necessary.
Do not should wires at construction site
Always follow the instruction of higher
authority.
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ACKNOWLEDGEMENT
The internship opportunity I had with UPSBC was a great chance for learning and
professional development. Therefore, I consider myself as a very lucky individual as I was
provided with an opportunity to be a part of it. I am also grateful for having a chance to meet
so many wonderful people and professionals who led me though this internship period.
Bearing in mind previous I am using this opportunity to express my deepest gratitude and
special thanks to the Mr.R.K Singh, Project Manager of this project who in spite of being
extraordinarily busy with his duties, took time out to hear, guide and keep me on the correct
path and allowing me to carry out my project at their esteemed organization and extending
during the training.
I express my deepest thanks to Mr.Satyendra Singh, Assistant engineer for taking part in
useful decision & giving necessary advices and guidance and arranged all facilities to make
training easier. I choose this moment to acknowledge his contribution gratefully.
It is my radiant sentiment to place on record my best regards, deepest sense of gratitude to
Mr.Sarvesh Kumar Pal, Junior Engineer and Mr.Pawan Singh, Site Engineer for their
careful and precious guidance which were extremely valuable for my study both theoretically
and practically.
I perceive as this opportunity as a big milestone in my career development. I will strive to use
gained skills and knowledge in the best possible way, and I will continue to work on their
improvement, in order to attain desired career objectives. Hope to continue cooperation with
all of you in the future,
Sincerely,
Mr.R.K Singh, Project Manager
Mr.Satyendra Singh, Assistant engineer
Mr.Sarvesh Kumar Pal, Junior Engineer
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Salient Features
Project cost : Rs. 2972.40 lac
Agency : UPSBC
Date of commencement : May, 2015
Target date of completion : March, 2017
Physical features
1. Total length of bridge 729.550m
2. No. of piers 16
3. Diameter of each pier 2.5m
4. No. of decks 17+1(RLWY)
5. Type of superstructure PSC
GIRDERS
6. Width of each Deck 8.5m
7. Slope along bridge length 1 in 30
8. Slope across bridge length 0.25 in 1
9. Length of underpass girder 37.5m
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MACHINES AND EQUIPMENTS USED
HYDRAULIC CRANE
A Hydraulic crane is a cable-controlled crane mounted on crawlers or rubber-
tired carriers or a hydraulic-powered crane with a telescoping boom mounted
on truck-type carriers or as self-propelled models. They are designed to easily
transport to a site and use with different types of load and cargo with little or no
setup or assembly. A mobile crane is a cable-controlled crane mounted
on crawlers or rubber-tired carriers or a hydraulic-powered crane with a
telescoping boom mounted on truck-type carriers or as self-propelled models.
They are designed to easily transport to a site and use with different types of load
and cargo with little or no setup or assembly.
Fig.(a) Hydraulic Crane On Site
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ON SITE AND PORTABLE CONCRETE MIXER
A concrete mixer is a device that homogeneously
combines cement, aggregate such as sand or gravel, and water to form concrete.
A typical concrete mixer uses a revolving drum to mix the components. For
smaller volume works portable concrete mixers are often used so that the concrete
can be made at the construction site, giving the workers ample time to use the
concrete before it hardens. An alternative to a machine is mixing concrete by
hand.
A typical portable concrete mixer uses a small revolving drum to mix the
components. For smaller jobs the concrete made at the construction site has no
time lost in transport, giving the workers ample time to use the concrete before it
hardens.
These concrete mixers are further divided based on their loading mechanism.
Cement, sand and other aggregates are loaded in a hydraulically operated hopper
and then poured in the mixing drum for final mixing and then can be unloaded by
tilting the drum. While in Hand Feed Concrete Mixers, cement, sand and other
aggregates are directly added to the mixing drum manually. These both type of
concrete mixers are highly popular and used in regular construction activities in
Africa, some Middle Eastern Countries and in the Indian subcontinent.
Fig.(b) Portable Concrete Mixer
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AUTO LEVEL
An automatic level, builder's auto level, levelling instrument or dumpy level is a
professional levelling tool that is used by land surveyors, builders, contractors
and engineers. The automatic level is known for providing users with consistent
levelling accuracy every time while also being fast, low cost and easy to use.
The automatic level is most commonly used in measuring, surveying, and setting
horizontal and vertical levels. The instrument is normally situated on a tripod and
then calibrated to a levelled position using levelling screws. The operator of the
automatic level then looks through the telescope attached to the instrument, while
a second person holds a graduated staff or tape measure at the position under
measurement.
Fig.(c) An Auto Level
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PRE-STRESSING JACKS
The tensioning of the steel strand (or individual wires) is usually by means of
hydraulic jacks. In pre-tensioning, single strand jacks may be used. In post-
tensioning the strands are often grouped to form tendons. These may be stressed
by large, multi-strand jacks. The load induced into the strand is determined from
the pressure in the hydraulic oil supplied to the jack or from the extension of the
strand. Wedge grips are used to grip each strand during stressing and to hold the
strand permanently in the tendon anchor after stressing. The jack is removed after
stressing and anchoring. In post-tensioning the pre-stressing force is applied
directly to the concrete. In the case of pre-tensioning the anchor holds the strands
until after the concrete has gained sufficient strength; the strands are then
released, transferring the pre-stressing force to the concrete.
Fig.(d) Pre-Stressing Jack And Machine
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PRESSURE GROUTING MACHINE
Pressure grouting involves injecting a grout material into generally isolated pore
or void space of which either the configuration or volume are known, and is often
referred to simply as grouting. The grout may be a cementious, resinous,
or solution chemical mixture. The greatest use of pressure grouting is to improve
geo materials (soil and rock). The purpose of grouting can be either to strengthen
or reduce water flow through a formation. It is also used to correct faults
in concrete and masonry structures. Since first usage in the 19th century, grouting
has been performed on the foundation of virtually every one of the world’s
large dams, in order to reduce the amount of leakage through the rock, and
sometimes to strengthen the foundation to support the weight of the overlying
structure, be it of concrete, earth, or rock fill. Although very specialized, pressure
grouting is an essential construction procedure that is practiced by specialist
contractors and engineers around the world.
Fig.(e) Grouting System
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NEEDLE VIBRATORS
These are also known as immersion vibrators. It has a steel tube, called a poker,
with one end being closed and rounded. There is an eccentric vibrating element
inside it. The poker is connected to an electric motor, sometimes a diesel motor,
through a flex tube.
These needle vibrators come in a variety of sizes from 40 to 100 mm in diameter.
The poker’s diameter is determined by the spacing between the reinforcing bars
in the form work. The general range of vibrations for a needle vibrator is between
3000 to 6000 rpm. The period of vibration necessary can be from 30 seconds to
2 minutes and the concrete should be placed in layers no more than 600mm high.
fig.(f) Needle Vibrator
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COMPONENTS OF BRIDGE
REINFORCED EARTH WALL PANELS
Reinforced Earth retaining wall panels are coherent gravity structures engineered
to resist specific loading requirements. The primary components of a Reinforced
Earth wall consist of alternating layers of granular backfill, and linear metallic,
high-adherence soil reinforcing strips or ladders to which a modular precast
concrete facing is attached. Its strength and stability are derived from the
frictional interaction between the granular backfill and the reinforcements,
resulting in a permanent and predictable bond that creates a unique composite
construction material.
Reinforced Earth retaining walls are an economical way to meet every-day earth
retention needs for highway and bridge grade separations, railroads and mass
transit systems, waterfronts, airports, loading docks, industrial facilities and
commercial and residential developments. They are also used in response to
difficult design conditions such as very high structures, restricted space, where
obstructions within the soil mass are present and poor foundation soils. The
inherent strength and flexibility of the overall wall system gives designers a
powerful way to economically solve difficult stability issues for structures subject
to flooding or other hydrodynamic forces, or those in seismically active areas.
Benefits include:
Considerable advantages over cast-in-place, both in construction time and
quantity of materials
Flexibility, making it possible to build directly upon compressible soils
High load-carrying capabilities, both to static and dynamic loads
Ease of installation since construction using prefabricated components is
rapid and predictable
Superior appearance since the facing is highly suited for architectural finishes
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GEOMATS
The geomats are used to tie the reinforced earth wall panels of both sides.
These geomats resists the horizontal pressure coming over the reinforced
earth wall panels.
Geomats are three-dimensional water permeable polymer or other
synthetically materials’ structures, thermally jointed with each other.
Geomats are three-dimensional water permeable polymer or other
synthetically materials’ structures, thermally jointed with each other.
Geomats are three-dimensional water permeable polymer or other
synthetically materials’ structures, thermally jointed with each other.
GEOTEXTILES
Geotextiles are permeable fabrics which, when used in association
with soil, have the ability to separate, filter, reinforce, protect, or drain.
Geotextiles are typically made from polypropylene or polyester.
Gaps between the reinforced earth wall panels are covered with geotextiles
by pasting over them using any sticky material.
A filter pipe placed parallel to reinforced earth wall is also covered with
the geotextile.
PIER OR PIER FOUNDATION
A pier is a raised structure typically supported by well-spaced piles or pillars.
Bridges, buildings, and walkways may all be supported by piers. Their open
structure allows tides and currents to flow relatively unhindered, whereas the
more solid foundations of a quay or the closely spaced piles of a wharf can act as
a breakwater, and are consequently more liable to silting. Piers can range in size
and complexity from a simple lightweight wooden structure to major structures
extended over 1600 metres. In American English, pier may be synonymous
with dock.
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Materials for piers and abutments:
The following types of materials are generally used for the construction of piers
and abutments:
a) Mass concrete of M-10 grade corresponding to mix proportion of 1:3:6 with
40 mm maximum size of aggregates.
b) Reinforced concrete of M-15 grade corresponding to mix proportion of 1:2:4.
c.) Coursed rubble masonry in cement mortar of proportions 1:4
d) Brick masonry in cement mortar of proportions 1:6
e)Prestressed concrete for the piers particularly in viaducts with tall piers.
Concrete of M-30 to M-40 grade is the minimum requirement for Prestressed
concrete piers.
The maximum permissible compressive and tensile stresses in the various types
of the materials in the substructure are compiled and written in the form of
tables before the design.
Forces to be considered on a pier:
Design of the piers involves the consideration of various forces acting on the
pier. Forces that are considered to be acting on the piers are:
1. Dead load of superstructure and pier
2. Live load of vehicles moving on the bridge
3. Effect of eccentric live loads
4. Impact effect for different classes of loads
5. Effect of buoyancy on the submerged part of the pier
6. Effect of wind loads acting on the moving vehicles and superstructure
7. Forces due to water current
8. Longitudinal forces due to tractive effort of vehicles
9. Longitudinal forces due to braking of vehicles
10. Longitudinal forces due to resistance in bearings
11. Effect of earthquake forces
12. Forces due to the collision for piers in navigable rivers.
Stability analysis for piers is generally made by considering some of the critical
forces which will have significant effect on the stresses developed in the piers.
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BEARING
A bridge bearing is a component of a bridge which typically provides a resting
surface between bridge piers and the bridge deck. The purpose of a bearing is
to allow controlled movement and thereby reduce the stresses involved.
Movement could be thermal expansion or contraction, or movement from
other sources such as seismic activity. The bearings used consisted of
following types:
1. Pin
2. Roller
3. Rocker
4. Metal sliding bearings
Fig.(j) Bearing Before Installation And After Installation
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BRIDGE DECK
A bridge deck or road bed is the roadway, or the pedestrian walkway, surface of
a bridge, and is one structural element of the superstructure of a bridge. It is not
to be confused with any deck of a ship. The deck may be constructed
of concrete, steel, open grating, or wood. Sometimes the deck is covered
with asphalt concrete or other pavement. The concrete deck may be an integral
part of the bridge structure (T-beam or double tee structure) or it may be
supported with I-beams or steel girders.
When a bridge deck is installed in a through truss, it is sometimes called a floor
system. A suspended bridge deck will be suspended from the main structural
elements on a suspension or arch bridge. On some bridges, such as a tied-
arch or a cable-stayed, the deck is a primary structural element, carrying tension
or compression to support the span.
ABUTMENT
In engineering, abutment refers to the substructure at the ends of a
bridge span or dam whereon the structure's superstructure rests or contacts.
The following are the uses of abutment in construction:-
To transfer loads from a superstructure to its foundation elements.
To resist and/or transfer self-weight, lateral loads (such as the earth pressure)
and wind loads.
To support one end of an approach slab.
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PRESTRESSING
Prestressed concrete is a method for overcoming concrete's natural
weakness in tension. It is a material that has the characteristics of high
strength concrete in compression and high ductile strength steel for tension.
The loss in material strength due to stressing can be computed and lies at
the stressed concrete shape. The bending shape should be opposite of the
applied force it will service. It can be used to
produce beams, floors or bridges with a longer span than is practical with
ordinary reinforced concrete. It is often used in commercial and residential
construction as a foundation slab. Prestressing tendons (generally of
high tensile strength steel cable or rods) are used to provide a clamping load
which produces a compressive stress that balances the tensile stress that the
concrete compression member would otherwise experience due to a
bending load. Traditional reinforced concrete is based on the use
of steel reinforcement bars, rebars, inside poured concrete. Prestressing can
be accomplished in three ways: pre-tensioned concrete, and bonded or
unbonded post-tensioned concrete.
METHOD OF PRE-STRESSING:
POST-TENSIONING VIA HYDRAULIC JACK
The wires are stretched after the concrete has hardened: which are either
encased in pipes or sheaths or holes are left in the concrete through which
wires are subsequently threaded. The wires in this method have to be held
stretched permanently by mechanical mean i.e. Anchors. There is no
bond b/w wires and concrete. The reinforcement in the former method
consist of the few large or several small cables made of high tensile steel
wires laid in one or more rings around a core.
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SHEATHING OR DUCTS
These are provided for avoiding the bonding b/w concrete and
tendon wires.
These may be of either steel, aluminium or PVC.
Fig.(k) Steel Ducts Along With Reinforcement
STRANDS
Wires are bound to form strands.
These are made up of high grade tensile steel.
Fig.(l) Tendon
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PRE-STRESSED CONCRETE
The technique of pre stressing eliminates tracking of concrete under all stages of
loading and enables the entire section to take part in resisting moments.as dead
load moments are neutralised and the shear stresses are reduced, the section
required are much smaller than in reinforced concrete.
Advantages
Large reduction in traditional reinforcement requirements as tendons
cannot destress in accidents.
Tendons can be easily weaved allowing a more efficient design approach.
Higher ultimate strength due to bond generated between the strands and
concrete.
No long term issues with maintaining the integrity of the anchor/dead end.
Problems likely to cause during or after concreting
Segregation
Segregation of concrete can be defined as separation of coarse aggregate from
mortar, resulting in their non-uniform distribution. Improper mix proportion
resulting in large proportion of coarse particles as compared to small
proportion of fine particles caused the separation of coarse particles from
mortar.
Honeycombing
The separation of coarse aggregate from mortar leaves voids in coarse aggregate
unfilled and this phenomenon is called honeycombing. Honeycombing decreases
density of concrete and hence reduction in strength of concrete.
Bleeding
Bleeding is the form of segregation in which water in a concrete mix rises to the
surface during placing it. It is because more water is present than is necessary for
the cement paste to lubricate the aggregate particles and the solid constituents of
26. 25
the mix are able to hold all the mixing water when they are settled down. Thus
the water rises up and appears on the surface of compacted concrete.
Precautions to be taken during placing of concrete
Under no circumstances, the water should be added to the concrete during
its passage from mixer to the formwork.
The formwork or the surface which has to receive the fresh concrete should
be properly cleaned, prepared, and well watered.
The concrete should be thoroughly worked around the reinforcement and
trapped in such a way that no honeycomb surface appears on the removal
formwork.
The concrete should be placed on the formwork as soon as possible.
During placing it should be seen that all edges and corners of the concrete
surface remain unbroken, sharp, and straight in line.
The placing of concrete should be carried out uninterrupted between pre-
determined construction joints.
Production of concrete:
The design of concrete mix involves the determination of the most rational
proportions of ingredients of concrete to achieve a concrete which is workable in
its plastic state and will develop the required qualities when hardened.
Concrete is graded according to its compressive strength. The various grades of
concrete as stipulated in IS: 456-2000 and IS: 1343-1980 are shown in table
below-
GROUP DESIGNATION CHARACTERSTIC COMP.
STRENGTH(N/mm2
)
Ordinary concrete M 10
M 15
M 20
10
15
20
Standard concrete M 25 25
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M 30
M 35
M 40
M 45
M 50
M 55
30
35
40
45
50
55
High strength concrete M 60
M 65
M 70
M 75
M 80
60
65
70
75
80
Table (1) Showing Characteristic Compressive Strength For Different Mix
Of Concrete
The proportion of cement, sand and coarse aggregate for a desired strength can
be either adopted or rationally designed.
A concrete mix in which the proportions are adopted is referred to as nominal mix
GRADE CEMENT COARSE
SAND
AGGREGATE
(10 mm)
AGGREGATE
(20mm)
M 30 1 1.380 1.112 1.668
M 35 1 1.300 1.152 1.728
M 40 1 1.220 1.120 1.680
M 45 1 1.020 1.080 1.620
Table(2) Showing Proportions Of Constituents For Nominal mix
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QUALITY CONTROL OF CONCRETE
Cube strength of concrete
Compressive strength test on 150mm cube of concrete is tested under
destructive load and it can’t be reused once the test is over
The compressive strength of a cube is an indication of the strength of
concrete it is possible to co-relate the flexural compressive and flexural
tensile strength of concrete.
It helps in determining whether the mix proportion are satisfactory or
need some changes
If concrete cubes from the same mix are tested at different period of time,
it helps in determining the rate of gain of strength, which in turn, helps in
determining the time of removal of formwork.
Fig.(m) Universal Testing Machine (UTM)
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Aggregate impact value
This test is done to determine the aggregate impact value of coarse
aggregates as per IS: 2386 (Part IV) – 1963. The apparatus used for
determining aggregate impact value of coarse aggregates is
Impact testing machine conforming to IS: 2386 (Part IV)- 1963,IS Sieves of
sizes – 12.5mm, 10mm and 2.36mm, A cylindrical metal measure of 75mm
dia. and 50mm depth, A tamping rod of 10mm circular cross section and
230mm length, rounded at one end and Oven.
Fig.(n) Impact Value Testing Machine
Sieve analysis
Sieve analysis helps to determine the particle size distribution of the coarse
and fine aggregates. This is done by sieving the aggregates as per IS: 2386
(Part I) – 1963. In this we use different sieves as standardized by the IS code
30. 29
and then pass aggregates through them and thus collect different sized
particles left over different sieves.
Fig.(o) Sieves Along With Vibrator
Flakiness and elongation index
FLAKINESS INDEX
Aggregate particles are classified as flaky when they have a thickness (smallest
dimension) of less than 0.6 of their mean sieve size. The flakiness index of an
aggregate sample is found by separating the flaky particles and expressing their
mass as a percentage of the mass of the sample tested. This test is not applicable
to aggregate passing6.30mmsieveandretainedas63.0mmsieve.
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ELONGATION INDEX
Aggregate particles are classified as elongation when they have a length
(greatest dimension) of more than 1.8 of their mean sieve size. The elongation
index is found by separating the elongation particles and expressing their mess
as a percentage of the mass of sample tested. The test is not applicable to
material passing 6.30 mm sieve or retainedon50 mmsieve.
Slump cone test
The concrete slump test is an empirical test that measures workability of
fresh concrete. The test measures consistency of concrete in that specific
batch. It is performed to check consistency of freshly made concrete.
Consistency refers to the ease with which concrete flows. It is used to
indicate degree of wetness.
