NATIONAL UNIVERSITY OF SCIENCE AND
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TECHNOLOGY
“THINK IN OTHER TERMS”
FACULTY OF ENGINEERING
DEPARTMENT OF CIVIL AND WATER ENGINEERING
COURSE NAME : CONSTRUCTION TECHNOLOGY
COURSE CODE: TCW 2207
LECTURER: MR MUDHINDI
GROUP MEMBERS
PANASHE KARIWO N02124717B
DAVID M ZHOU N02160118Y
MCLAN NHIKA N02123560E
BONGANI NCUBE N021
PROGRESS MUHENYERI N02132991Y
METHODS OF TESTING MATERIALS ON SITE AND OFF SITE.
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GENERAL OVERVIEW OF TESTING OF MATERIALS

to the main types of engineering materials found in construction are concrete, bituminous substances ,steels, soils and
bricks

the testing of construction materials can be physical, chemical, verifying quantity and checking for damage.

there are many different types of tests that occur during construction and may be grouped into off-site and on-site tests

the main site tests that will be discussed here are on materials only. a site test is one that is done outside the lab it is
usually very quick, cheap and produces results that are not as accurate as the ones from a lab.
WHY DO WE NEED TO TEST CONSTRUCTION MATERIALS
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
the testing of construction materials is necessary as part of the quality control system.

to verify that materials comply with the required specification.

to achieve certification

to ensure safety.

to demonstrate compliance with legislative requirements, such as the building regulations.
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TESTS ON CONCRETE
SLUMP TEST

this test is performed to check the consistency of freshly made concrete. the slump test is
done to make sure a concrete mix is workable. the measured slump must be within a set
range, or tolerance, from the target slump. For all tests involving concrete it must first be
left to cure and harden. It is advised that test be carried out after 7,14 and 28 days. At 28
days concrete has fully hardened.
TOOLS AND APPARATUS USED FOR SLUMP TEST (EQUIPMENT):

standard slump cone (100 mm top diameter x 200 mm bottom diameter x 300 mm high)

small scoop - bullet-nosed rod (600 mm long x 16 mm diameter)

rule - slump plate (500 mm x 500 mm)
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Procedure of slump test for concrete

Clean the cone. Dampen with water and place on the slump plate. The slump plate should
be clean, firm, level and non-absorbent. Collect a sample of concrete to perform the slum
test.

Stand firmly on the foot pieces and fill 1/3 the volume of the cone with the sample.
Compact the concrete by roding 25 times. Roding means to push a steel rod in and out of
the concrete to compact it into the cylinder, or slump cone. Always rod in a definite pattern,
working from outside into the middle.

Now fill to 2/3 and again rod 25 times, just into the top of the first layer.

Fill to overflowing, Roding again this time just into the top of the second layer. Top up the
cone till it overflows.

Level off the surface with the steel rod using a rolling action. Clean any concrete from
around the base and top of the cone, push down on the handles and step off the foot pieces.

Carefully lift the cone straight up making sure not to move the sample.

Turn the cone upside down and place the rod across the up-turned cone.

Take several measurements and report the average distance to the top of the sample. If the
sample fails by being outside the tolerance (i.e. the slump is too high or too low), another
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SLUMP TEST
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When measuring the change in slump a ruler
or measuring tape is to be used .
It is measured from bottom of mix to
displaced centre it is usually approximated
and rounded off to the nearest cm
TESTING OF MATERIALS ON SITE AND OFF SITE.
VEBE TEST
• To determine the workability of fresh concrete by using a Vee-Bee consistometer as
per IS: 1199 – 1959. The apparatus used is Vee-Bee consistometer.
Procedure :
 A conventional slump test is performed, placing the slump cone inside the cylindrical
part of the consistometer.
 The glass disc attached to the swivel arm is turned and placed on the top of the
concrete in the pot.
 The electrical vibrator is switched on and a stop-watch is started, simultaneously.
 Vibration is continued till the conical shape of the concrete disappears and the concrete
assumes a cylindrical shape.
 When the concrete fully assumes a cylindrical shape, the stop-watch is switched off
immediately.
 The time is noted.
 The consistency of the concrete should be expressed in VB-degrees, which is equal to
the time in seconds recorded above
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TESTING OF MATERIALS ON SITE AND OFF SITE.
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TESTING CONCRETE
CUBE TEST
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
A concrete cube test is a test used to determine the compressive strength of concrete

For cube test two types of specimens either cubes of 15cm X 15cm X 15cm or 10cm X 10cm x 10cm depending upon the
size of aggregate are used

This concrete is poured in the mould and appropriately tempered so as not to have any voids. After 24 hours, moulds are
removed, and test specimens are put in water for curing.

The top surface of these specimen should be made even and smooth. This is done by placing cement paste and spreading
smoothly on the whole area of the specimen.

These specimens are tested by compression testing machine after seven days curing or 28 days curing.

Load should be applied gradually at the rate of 140 kg/cm2 per minute till the Specimens fails. The reading at the failure
is the maximum compressive strength of the concrete,
CUBE TEST
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PENETRATION TEST RESISTANCE ON HARDENED
CONCRETE

The penetration resistance of concrete is computed by measuring the exposed length of
probes driven into concrete. In order to estimate concrete strength, it is necessary to
establish a relationship between penetration resistance and concrete strength.

Such a relationship must be established for a given test apparatus, using similar concrete
materials and mixture proportions as in the structure. Procedures and statistical methods
provided in ACI 228.1R can be used for developing and using the strength relationship.
FACTORS INFLUENCE THE PENETRATION RESISTANCE TEST RESULT

Nature of the formed surfaces for instance wooden forms versus steel forms.

That is why correlation testing should be performed on specimens with formed surfaces
similar to those to be used during construction.

Probe penetration resistance is affected by concrete strength as well as the nature of the
coarse aggregate.
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PENETRATION TEST
LIMITATIONS AND ADVANTAGES

The probe test produces quite variable results and should not be expected to give
accurate values of concrete strength. It has, however, the potential for providing a
quick means of checking quality and maturity of in situ concrete. It also provides a
means of assessing strength development with curing. The test is essentially nondestructive, since concrete and structural members can be tested in situ, with only
minor patching of holes on exposed faces
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REBOUND HAMMER TEST

Rebound hammer test (Schmidt Hammer) is used to provide a convenient and
rapid indication of the compressive strength of concrete.

It consists of a spring controlled mass that slides on a plunger within a tubular
housing.

When the plunger of rebound hammer is pressed against the surface of
concrete, a spring controlled mass with a constant energy is made to hit
concrete surface to rebound back.

The extent of rebound, which is a measure of surface hardness, is measured
on a graduated scale.

This measured value is designated as Rebound Number (rebound index).

A concrete with low strength and low stiffness will absorb more energy to
yield in a lower rebound value.
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The operation of rebound hammer is shown in the figure below.
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STEEL TESTING
TENSILE STRENGTH

is the resistance of steel to breaking under tensile tension. It’s used to specify the point
when steel goes from elastic (temporary) to plastic (permanent) deformation.

Most steels and metals are very difficult to test on site they are usually perfect products that
have come from the industry and have already undergone request testing the only known
testing which is simple and straightforward and can be done on site would be using eye
observation.

The engineering charge would simply look at the metal and try to search for any defects in
it this defects would be mainly in the paint and on the metal itself if the paint is chipped
scratched or is peeling off anywhere on the metal the metal should be discarded as it is now
liable to corrosion .

Similarly if the metal has any cracks, holes or any signs of corrosion the metal should be
discarded because it will not last within the building that is being built instead the corrosion
could be spread further into the material and leads to a poor compromised structure.
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
TENSILE STRENGTH TESTING
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THE GRAPH OF RESULTS FOR STEEL TESTING
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Hardness tests of steel

these assess the hardness of steel by measuring the penetration of a locally induced
indentation

These include the Brinell, Rockwell and Vickers hardness tests

A load whose magnitude is known is swung onto the steel surface, producing a dent that
can be measured and its numerical value represents how hard the steel is
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TIMBER TESTING
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
Timber can be tested on site for its moisture content. The moisture content is usually expressed as a percentage and
calculated as the difference between the weight of the wet timber and the weight of the sample after drying.

For example, the moisture content of a piece of timber weighing 500g, and containing 250g of water can be
calculated as follows :
(weight of wet timber – weight of dry timber)/ oven-dry weight X 100%
= (500-250)/250 x 100
= 100%

There are two common methods for measuring the moisture content
TIMBER TESTING USING A MOISTURE METER

Pin-type meters these use two or more electrodes to measure the moisture content using
electrical resistance.

The more resistance to the electrical current the drier the timber, since water is a conductor
and timber is a natural insulator.

Pin less moisture meters , these pass an electromagnetic wave through a sample using a
specialized scanning plate. It creates a reading of the average moisture content in the
scanning area
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OVEN DRY-TESTING

This involves drying timber to a relatively constant weight in a ventilated oven at 102-105
degrees Celsius.

It is possible to establish a very accurate original moisture content percentage by drying a
piece of timber in an oven for several hours and testing it at regular intervals until its
weight stops changing.

While this method is very accurate , it is a slow process which can, if rushed, burn the
timber or render it unusable because of deformations.

It is also necessary to have the right kind of ventilated oven, which means it is impractical
in many instances thus this method in an off site type of testing materials.
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TIMBER OVEN DRY-TESTING
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TESTING BRICKS
COMPRESSIVE STRENGTH TEST

This test is done to know the compressive strength of brick.

It is also called crushing strength of brick.

Generally 5 specimens of bricks are taken to laboratory for testing and tested one by
one. In this test a brick specimen is put on crushing machine and applied pressure till it
breaks.

The ultimate pressure at which brick is crushed is taken into account. All five brick
specimens are tested one by one and average result is taken as brick’s
compressive/crushing strength
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WATER ABSORPTION TEST

In this test bricks are weighed in dry condition and let them immersed in fresh water for 24
hours.

After 24 hours of immersion those are taken out from water and wipe out with cloth.

Then brick is weighed in wet condition.

The difference between weights is the water absorbed by brick. The percentage of water
absorption is then calculated.

The less water absorbed by brick the greater its quality. Good quality brick doesn't absorb
more than 20% water of its own weight.
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EFFLORESCENCE TEST

Efflorescence is a crystalline , salty deposit that can occur on the surface on the bricks. It is
generally a white or off-white colour with a powdery appearance. To test for alkalis that
may cause efflorescence, a brick is immersed in fresh water for 24 hours and then left to
dry.

If the whitish layer is not visible on the surface then it demonstrates an absence of alkalis in
the brick. The ranges that should be followed are

About 10% of the brick surface accepted range

About 50% of the brick surface moderate range

Over 50% of the brick surface severely affected by alkalis
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
EFFLORESCENCE TEST
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HARDNESS TEST

The brick surface is scratched if no impression is left then it is of good quality.
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BRICK TESTING
SOUNDNESS TEST

Two bricks are held in each hand and struck together. They should not break and a clear
metallic ringing sound should be made if they are good quality. If not those bricks should
not be used.
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STRUCTURE TEST
A sample brick is broken and carefully inspected. If it is good quality there should be
no flows, cracks or holes on the broken face.

These two test above can be done on site thus therefore they are on site test.
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TESTING OF MATERIALS ON SITE AND OFF SITE.
BITUMEN AND BITUMINOUS MATERIALS
PENETRATE TEST

It measures the hardness or softness of bitumen by measuring the depth in tenths of a millimetre
to which a standard loaded needle will penetrate vertically in 5 seconds.

BIS had standardised the equipment and test procedure. The penetrometer consists of a needle
assembly with a total weight of 100g and a device for releasing and locking in any position.

The bitumen is softened to a pouring consistency, stirred thoroughly and poured into containers
at a depth at least 15 mm in excess of the expected penetration.

The test should be conducted at a specified temperature of 25 C.

It may be noted that penetration value is largely influenced by any inaccuracy with regards to
pouring temperature, size of the needle, weight placed on the needle and the test temperature.

A grade of 40/50 bitumen means the penetration value is in the range 40 to 50 at standard test
conditions. In hot climates, a lower penetration grade is preferred. The fig below shows a
schematic Penetration Test setup
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BITUMEN PENETRATION TEST
DIAGRAM TO ILLUSTRATE THE TEST
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Soil tests

Moisture content test on soil

Specific Gravity Test

Compaction Test on soil
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Moisture Content Test
The drying method test

Soil sample is weighed, put in an oven, dried at 110 +/-5 degrees c

After 24 hours, the sample is taken out and weighed again

The difference between the two weights is the moisture content in
the soil…
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Specific gravity test

Is a quantity giving the weight per unit volume of a particular soil.

Pycnometer method, Pycnometer is weighed in 4 different cases
that is empty weight (M1), empty + dry soil (M2), empty + water +
dry soil (M3) and Pycnometer filled with water (M4) at room
temperature. From these 4 masses specific gravity is determined by
below formula.

Specific Gravity Formula for Soil
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Compaction Test on soil
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
Compaction of soil is nothing but reducing air voids in the soil by densification. The degree of Compaction is
measured in terms of dry density of soil.

given soil sample sieved through 20mm and 4.75 mm sieves. Percentage passing 4.75mm and percentage retained
on 4.75mm are mixed with certain proportions.

Add water to it and leave it in air tight container for 20hrs. Mix the soil and divide it into 6 – 8 parts. Position the
mold and pour one part of soil into the mold as 3layers with 25 blows of ramming for each layer.

Remove the base plate and Weight the soil along with mold. Remove the soil from mold and take the small portion
of soil sample at different layers and conduct water content test. from the values find out the dry density of soil
and water content and draw a graph between them and note down the maximum dry density and optimum water
content of the compacted soil sample at highest point on the curve.
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SAND TESTING
SILT TEST

This test is used to measure the cleanliness of a sand sample by establishing the percentage
of silt present. This is important as too much silt will weaken the concrete.

A salt water solution of 5 ml salt to 500 ml water is poured to 50 ml in a measuring
cylinder. The sand sample is then added up to the 50 ml mark. More salt water solution is
poured up to 150 ml before shaking the cylinder well .

The mixture should be left to stand for 3 hours before measuring the height of the silt which
will have settled on top of the layer of sand. The height of the silt layer should not be more
than 6 ml, or 6% of the sand sample height.
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SILT TEST
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REFERENCES:

https://www.structuralguide.com/construction-material-testing

Material Testing - Civil Engineering Portal - Biggest Civil Engineering
Information Sharing Website (engineeringcivil.com)

https://theconstructor.org/building/codes-material-testing

What are the Types of Material Testing in Construction? - ForneyVault

https://iricen.gov.in/iricen/books_jquery/material_testing
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