aggregate testing ismail c t

8/6/2019 Aggregate Testing Ismail C T

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Aggregate

Testing


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CRUSHING VALUE TESTI.S 2386 (Part 4)-1963 describe method of testing of aggregate for concrete. The

compressive strength of concrete is mainly depended on aggregate crushing

strength.

Apparatus: I.S. sieve 12.5 mm, 10 mm, 2.36mm.Cylinder size 11.5 cm dia & 18 cm height.

Mould 15.2 cm & 13 cm height

Compressive testing machine.

Balance, weight.

Material: Oven dried sample


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Procedure: Take surface dry aggregate which are retained on 10mm sieve passing from 12.5 mm sieve

Fill the sample into the cylinder

Weight the sample at accuracy of 1 gm as W1.

Place the sample into mould into three uniform layers

Each layer being compacted by 25 strokes of iron rod having length of 16

mm dia and 60 cm length rod

Level the top surface of aggregate in the mould and keep the mould under

compression testing machine.Apply 40 ton load through a 15 cm &

plunger resisting on level surface.

The rate of loading should be uniform and total load should be applied

within 10 minutesPass material through 2.36 mm I.S sieve.

Weight portion passing through sieve as W2 and express a percentage of

total weight.

Calculation = W2/W1 * 100%


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I S Value :

For non wearing surface of concrete 45%

For wearing surface road runway 30%


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Aggregate Impact value Test

It shows the resistance of aggregate to sudden shock applied to it

For this aggregate passing from 12.5mm IS sieve and retained on 10mm IS sieve are used

Apparatus & Material: Aggregate impact testing machine

Balance Weight

IS sieve 12.5 mm IS sieve, 10 mm IS

sieve and 2.36 mm IS sieve

Oven dried aggregate

Tamping rod 10 mm dia, 230 mm long.


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Procedure: Take IS sieve passing from 12.5 mm IS sieve and retained on 10 mm

IS sieve

Fill this aggregate in cylinder in three equal layers, give 25 blows of iron rod to each

layer of aggregate

Take weight of aggregate in cylinder as W1

Make 15 blows on aggregate in cylinder with help of hammer having 14 Kg weight

and is allowed to fall free on aggregate from height of 380 mm

Than pass sample from 2.36 mm IS sieve and weight the sample passing from

sieve as W2

Aggregate impact value = W2/W1 * 100

Aggregate impact value

Result of test should not be above 45% for aggregate used in construction other

than road work

Result of test should not be above 30% for aggregate used in road work


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Aggregate Abrasion Test:

Value of aggregate to resist abrasion is found out by this test

Result of this test are used for selecting aggregate in construction of roads,

wear house floor, pavements etc.

Apparatus: Loss Angeles Abrasion Testing machine

Sieve 12.5 mm, 10 mm and 1.7 mm


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Procedure: Take 5 Kg of sample of aggregate which passes through 12.5 mmIS sieve and retained on 10 mm IS sieve

Dry this sample in oven at 105 to 100 degree centigrade temperature

Now put the aggregate in the drum of Loss Angles abrasion testing machine

(dia of drum is 70 cm and length of drum is 50cm IS sieve)

Now add steel sphere of weight 390 to 445 gm of radius 4.8 cm into the drum.

Now rotate drum at speed of 30 to 33 RPM for500 revolution

Now take out aggregate from drum and sieve sample from 1.7 mm IS sieve

Now W1 = aggregate total weight 5 Kg

W2 = aggregate weight passed from IS 1.7 mm IS sieve

Aggregate abrasion value is W2/W1 * 100

Aggregate abrasion value:

Should not be greater than 30% for aggregate used in road

And not greater than 50% for aggregate used in building construction


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GradingGrading No ofNo ofspheresphere

Weight ofWeight ofChargeCharge(gm)(gm)

A A 1212 5000+/5000+/-- 2525

BB 1111 4584+/4584+/-- 2525

CC 88 3330+/3330+/-- 2020

DD 66 2500+/2500+/-- 1515

EE 1212 5000+/5000+/-- 2525

FF 1212 5000+/5000+/-- 2525

WEIGHT OF CHARGE AND NUMBER OF

SPHERES FOR DIFFERENT GRADING

aggregate testing ismail c t

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