SOUNDNESS TEST OF AGGREGATE IS 2386-Part 5

SOUNDNESS TEST OF AGGREGATE

This method of aggregate testing covers the determination of the soundness of aggregate by measuring the resistance to disintegration in a saturated solution of Sodium sulphate or Magnesium sulphate. The soundness test of aggregate determines an aggregate resistance to disintegration by weathering. The aggregate sample is repeatedly immersed in a solution of sodium sulfate or magnesium sulfate to perform the soundness test.

Test standard : IS 2386-Part 5 : 1963

Test Apparatus

1. Anhydrous sodium and magnesium sulphate.
2. IS Sieves of size 80mm, 63mm, 50mm, 40mm, 31.5mm, 25mm, 20mm, 16mm, 12.5mm, 10mm, 8mm, 4.75, 4.0mm, 2.36mm, 1.18mm, 600 microns, 300 microns, 150 microns
3. Perforated wire mesh containers
4. Glass Vessel and Beakers
5. Weighing balance of accuracy 0.1gms & 1.0gms
6. Hot air electric oven

Preparation of Solution

Sodium sulphate solution:

Saturated solution of sodium sulphate is prepared by dissolving 420 gms of anhydrous sodium sulphate salt in one litre of water. Stir the solution thoroughly during the addition of salt & at frequent intervals until used. Solution to be cooled at room temperature of 27± 20 °C and maintained at that temperature for atleast 48 hours before use. When used the solution shall have specific gravity of not less than 1.151 & not more than 1.174.

Magnesium sulphate solution:

Saturated solution of Magnesium sulphate is prepared by dissolving 400 gms of anhydrous magnesium sulphate salt in one litre of water. Stir the solution thoroughly during the addition of salt & at frequent intervals until used. Solution to be cooled at room temperature of 27± 10 °C and maintained at that temperature for atleast 48 hours before use. When used the solution shall have specific gravity of not less than 1.295 & not more than 1.308.

Sample Preparation

For Fine aggregates:

It consists of all materials passing 10mm IS Sieve. The test sample shall be of such a size that it will yield not less 100 gms of the following sizes, which shall be available in amounts of 5% or more, expressed in terms of the following :

Passing IS Sieve	Retained IS Sieve
600 Micron	300 Micron
1.18 mm	600 Micron
2.36 mm	1.18 mm
4.75 mm	2.36 mm
10.0 mm	4.75 mm

• Sample of fine aggregate shall be thoroughly washed over 300 micron IS Sieve.
• Dry the sample to constant weight at 105-110 °C temperature in a hot air electric oven & separated into different sizes using above sieves.
• 100 gms sample shall be weighed out of each of the separated fractions.
• Fine aggregates sticking in the mesh of the sieves shall not be used in preparing test sample.

For Coarse aggregates:

It consists of all materials retained on 4.75mm IS Sieve. The test sample shall be of such a size that it will yield not less than the following amounts of different sizes, which shall be available it amounts of 5% or more, expressed in terms of the following:

IS Sieve (Square Hole Sieve)	Test sample (Yield)
10mm to 4.75mm	300 gms
20mm to 10.0mm	1000 gms
Consisting of:
12.5mm to 10.0mm	33%
20.0mm to 12.5mm	67%
40mm to 20.0mm	1500 gms
Consisting of:
25mm to 20.0mm	33%
40mm to 25mm	67%
63mm to 40mm	3000 gms
Consisting of:
50mm to 40mm	33%
63mm to 50mm	67%

• Sample of fine aggregate shall be thoroughly washed over 4.75mm IS Sieve.
• Dry the sample to constant weight at 105-110 °C temperature in a hot air electric oven & separated into different sizes using above sieves.
• Test sample shall be weighed out of each of the separated fractions.

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Test Procedure for soundness test of aggregate

1. The test sample shall be immersed in the prepared solution of sodium or magnesium sulphate for not less than 16 hours and not more than 18 hours in such a manner that the solution covers them to a depth of at least 15mm.
2. The containers shall be covered to reduce evaporation & prevent the accidental addition of extraneous substances.
3. Sample immersed in the solution shall be maintained at a temperature of 27± 1 °C for the immersion period.
4. After the immersion period, aggregate shall be removed from the solution, permitted to drain for 15± 5 minutes & dried to constant weight in oven at a temperature of 105-110 °C, which shall be achieved when the two successive weights of the same differ by less than 0.1gm for fine aggregate & 1.0 gms for coarse aggregates.
5. Test samples shall be allowed to cool at room temperature & again immersed in the prepared solution of sodium or magnesium sulphate.
6. The process of alternate immersion and drying shall be repeated until the specified number of cycles is achieved.
7. After the completion of final cycle, cool the sample & wash free from sodium or magnesium sulphate solution by the reaction of wash water with barium chloride.
8. Dry each fraction of sample to constant weight in hot air oven at temperature of 105-110°C & weighed.

Fine aggregate shall be sieved on 300 micron IS Sieve & coarse aggregate over the sieve shown below for the appropriate
size of particle:

Weighted average from the percentage of loss of each fraction based on the grading of the sample as received for examination shall be calculated & its total value shall be reported.

Calculation

Average corrected loss %

G = [(F/100)xC]

Actual loss %

F = [E/Dx100]

Fraction %

C = (B/A)x100)

A = Total weight of sample (gms)

B = Total Weight of fraction (gms)

D = Weight of the test fraction before test (gms)

E = Weight of the material passing IS sieve after test (gms)

Limit

As per lS: 383

Max. 12% for Sodium sulphate solution

max. 18% with Magnesium sulphate solution

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