Transportation EXPTS

8/3/2019 Transportation EXPTS

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6. We take the weight W (calculated as above) of the mix soil and place it in the mould.

7. Then we place a filter paper and the displacer disc on the top of soil.

8. We keep the mould assembly in static loading frame and compact by pressing the displacer

disc till the level of disc reaches the top of the mould.

9. We keep the load for some time and then release the load. Remove the displacer disc.

The test may be conducted for both soaked as well as unsoaked conditions. If the sample is to be soaked, in cases of compaction, put a filter paper on the top of the soil and place the

adjustable stem and perforated plate on the top of filter paper.

For Penetration Test

1. We place the mould assembly with the surcharge weights on the penetration test machine.

2. Then we seat the penetration piston at the centre of the specimen with the smallest possible

load, but in no case in excess of 4 kg so that full contact of the piston on the sample is

established.

3. We set the stress and strain dial gauge to read zero. Apply the load on the piston so that the

penetration rate is about 1.25 mm/min.

4. We record the load readings at penetrations of 0.5, 1.0, 1.5, 2.0, 2.5, 3.0, 4.0, 5.0, 7.5, 10 and

12.5 mm. Note the maximum load and corresponding penetration if it occurs for a penetration

less than 12.5 mm.

5. We detach the mould from the loading equipment. Take about 20 to 50 g of soil from the top

3 cm layer and determine the moisture content.

6. The C.B.R. values are usually calculated for penetration of 2.5 mm and 5 mm.

Penetration of plunger (mm) Standard load (kg)

2.5

5.0

1370

2055

Generally the C.B.R. value at 2.5 mm will be greater that at 5 mm and in such a case/the

former shall be taken as C.B.R. for design purpose. If C.B.R. for 5 mm exceeds that for 2.5

mm, the test should be repeated. If identical results follow, the C.B.R. corresponding to 5 mm

penetration should be taken for design.

C.B.R. = {Test load/Standard load}* 100


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Name of the experiment: Aggregate Impact Value Test

Aim of the experiment: This test is done to determine the aggregate impact value of coarse

aggregates to check the toughness of the aggregates.

Apparatus required:

Impact testing machine, 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.


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Fig. Instrument used in the AIV test

Test Procedure:

Preparation of Sample

i) The test sample should conform to the following grading:

- Passing through 12.5 mm IS Sieve

- Retention on 10 mm IS Sieve

ii) The sample should be oven-dried for 4hrs. at a temperature of 100 to 110 oC 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.

iii) 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.

iv) 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.


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ii) The ratio of the weight of the fines formed to the total sample weight should be expressed as a

percentage.

Aggregate impact value = (B/A) x 100%

iii) Two such tests should be carried out and the mean of the results should be reported.

Name of the experiment: Los Angeles Abrasion test

Aim of the experiment: (i) to determine the Los Angeles abrasion value.

(ii) to find the suitability of aggregates for use in road construction.

Apparatus required:

(i) Los Angeles Machine: It consists of a hollow steel cylinder, closed at both the ends with an

internal diameter of 700 mm and length 500 mm and capable of rotating about its horizontal axis. A

removable steel shaft projecting radially 88 mm into cylinder and extending full length (i.e.500 mm)

is mounted firmly on the interior of cylinder. The shelf is placed at a distance 1250 mm minimum

from the opening in the direction of rotation.

(ii) Abrasive charge: Cast iron or steel balls, approximately 48mm in diameter and each weighing

between 390 to 445g; six to twelve balls are required.
http://theconstructor.org/building/building-material/aggregates/http://theconstructor.org/building/building-material/aggregates/


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Fig. Los Angeles machine

(iii) Sieve: 1.70, 2.36,4.75,6.3,10,12.5,20,25,40,50,63,80 mm IS Sieves.

(iv) Balance of capacity 5kg or 10kg

(v) Drying oven

(vi) Miscellaneous like tray

Test Procedure:

The test sample consists of clean aggregates dried in oven at 105 110C.

(i) We select the grading to be used in the test such that it conforms to the grading to be used in

construction, to the maximum extent possible.

(ii) We take 5 kg of sample for gradings A, B, C & D and 10 kg for gradings E, F & G.

Grading No of Steel balls Weight of charge in gm

A 12 5000 25

B 11 4584 25
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C 8 3330 20

D 6 2500 15

E 12 5000 25

F 12 5000 25

G 12 5000 25

(iii) Then we choose the abrasive charge depending on grading of aggregates.

(iv) We place the aggregates and abrasive charge on the cylinder and fix the cover.

(v) We then rotate the machine at a speed of 30 33 revolutions per minute. The number of

revolutions is 500 for gradings A, B, C & D and 1000 for gradings E, F & G. The machine should be

balanced and driven such that there is uniform peripheral speed.

(vi) The machine is stopped after the desired number of revolutions and material is discharged to a

tray.

(vii) The entire stone dust is sieved on 1.70 mm IS sieve.

(viii) The material coarser than 1.7mm size is weighed correct to one gram.

OBSERVATIONS:

Original weight of aggregate sample = W 1 g

Weight of aggregate sample retained = W 2 g

Weight passing 1.7mm IS sieve = W 1 - W 2 g

Abrasion Value = {(W 1 - W 2 ) / W 1 }*100


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Name of the experiment: Bitumen Softening Point Test

Aim of the experiment: This test is done to determine the softening point of bitumen i.e. thetemperature at which the bitumen softens.

Apparatus required: i) Ring and ball apparatus

ii) Thermometer Low Range: -2 to 80 oC, Graduation 0.2 oC

High Range: 30 to 200oC, Graduation 0.5 oC


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Fig. Ring and ball apparatus set-up

(i) Ring and ball apparatus:

Rings Two square-shouldered brass rings

Pouring Plate A flat, smooth, brass plate approximately 50 by 75 mm (2 by 3 in.).

Balls Two steel balls, 9.5 mm (38 in.) in diameter, each having a mass of 3.50 6 0.05 g.

Ball -Centering Guidestwo brass guides for centering the steel balls, one for each ring, conforming

to the general shape and dimensions

Bath A glass vessel, capable of being heated, not less than 85 mm in inside diameter and not lessthan 120 mm in depth from the bottom of the flare. An 800-mL, low-form Griffin beaker of heat-

resistant glass meets this requirement.

Ring Holder and Assembly A brass holder designed to support the two rings in a horizontal

position. The bottom of the shouldered rings in the ring holder shall be 25 mm (1.0 in.) above the

upper surface of the bottom plate, and the lower surface of the bottom plate shall be 16 mm from the

bottom of the bath.

(ii) Thermometers:A Low Softening Point Thermometer, having a range from 2 to + 80C or 30 to 180F and a High

Softening Point Thermometer, having a range from 30 to 200C or 85 to 392F

The appropriate thermometer shall be suspended in the assembly as shown in Fig. 1 (d) so that the

bottom of the bulb is level with the bottom of the rings and within 13 mm (0.5 in.) of the rings, but

not touching them or the ring holder.

Preparation of sample:

i) The sample should be just sufficient to fill the ring. The excess sample should be cut off by a knife.


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8. Result will be the grade of bitumen.

9. Take at least three reading.

Name of the experiment: Elongation index test for aggregates

Aim of the experiment: To classify the aggregate elongation by measuring the individuallength.

Apparatus required:

Elongation gauge -- A metal gauge of the pattern shown in figure.

Fig. length gauge used for determining Elongation Index

Test Procedure:


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1. The sample of aggregates to be tested is sieved through a set of sieves and separated into

specified size ranges.

2. The aggregates from each of the size range are then individually passed through the

appropriate gauge of the length gauge with the longest side in order to separate the

elongated particles.

3. The gauge length will be 1.8 times the main size of the aggregate.4. The portion of elongated aggregate having length greater than the specified gauge from

each range is weighed.

5. It is expressed as a % of the total weight of the sample, to get the elongation index.

In other words, it is the % by weight of particles whose greatest dimension or length is

greater than one or four fifth or 1.8 times their mean dimension.

This test is applicable to aggregates with sizes larger than 6.3 mm only.

Name of the experiment: Flakiness index test for aggregates

Aim of the experiment: To classify the aggregates w.r.t. their flakiness.

Apparatus required: Flakiness gauge A metal thickness gauge of the pattern shown in figure.

Fig. thickness gauge used for determining Flakiness Index

Test Procedure:


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1. The sample of aggregates to be tested is sieved through a set of sieves and separated into

specified size ranges.

2. Now to separate the flaky material, the aggregates which pass through the appropriate

elongated slot of the thickness gauge are found.

3. The width of the appropriate slot would be 0.6 times the average of the size range.

4. The flaky material passing the appropriate from each size range of test aggregates are addedup and let this weight be w.

5. Let, the total weight of sample taken from different size ranges is W.

6. Then the flakiness index is given by (100w/W) %.

In other words, it is the % of flaky materials, the widths of which are less than 0.6 times the

mean dimensions.

This test is applicable to aggregates with sizes larger than 6.3 mm only.

Transportation EXPTS

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