SOUNDNESS TEST OF AGGREGATES (IS-2386-PART-5)

Objective

This test is intended to study the resistance of coarse and fine aggregates to weathering action and to judge the durability of the coarse aggregate.

Apparatus

Name	Capacity	Least count
Balance	500 g	0.1 g
Balance	5000 g	1 g
Oven	105 to 1100C
Sieves	80 mm, 63 mm, 40 mm, 31.5 mm, 25 mm, 20 mm, 16 mm, 12.5 mm, 10 mm, 8.0 mm, 4.75 mm, 4.0 mm, 2.36 mm, 1.18 mm, 600 micron, 300 micron, 150 micron
Wire mesh basket
container

Chemical Solution

• Sodium Sulphate Solution
• Magnesium Sulphate Solution

Preparation of Test Sample For Fine Aggregate

• Wet sieve the sample through a nest of IS sieves, the lower being 300 micron and the upper being 10 mm size.
• The material passing 10 mm sieve and retained on 300 micron sieve is then dried and taken for the test.
• The sample collected as above is again sieved through a series of sieves such as 10 mm, 4.75 mm, 2.36 mm, 1.18 mm, 600 micron and 300 micron.
• The amount of sample to be taken for sieving is such that, it will yield not less than 100 g of each of the following sizes.

Passing	Retained
10 mm	4.75 mm
4.75 mm	2.36 mm
2.36 mm	1.18 mm
1.18 mm	600 micron
600 micron	300 micron

• Weigh 100 g of sample from each of the separated fraction and place it in separate containers for the test.
• Note- Fine aggregates sticking in the meshes of the sieves is not used in preparing the sample.

Preparation of Test Sample For Coarse Aggregate

• Wash the coarse aggregate through 4.75 mm IS sieve and dry the material retained on the sieve in an oven maintained at a temp of 105 to 110⁰C, till it attains a constant mass.
• Sieve the dried sample to separate it into different size fractions using sieves of sizes 80 mm, 63 mm, 40 mm, 20 mm, 10 mm, 4.75 mm.
• The sample should be of such an amount that it will yield not less than the following amount of the different sizes, which shall be available in amounts of 5 percent or more.

 

Size	Yield
10 mm to 4.75 mm	300 g
20 mm to 10 mm	1000 g (consisting of 12.5 mm to 10 mm = 33% and 20 mm to 12.5 mm = 67%)
40 mm to 20 mm	1500 g (consisting of 25 mm to 20 mm = 33% and 40 mm to 25 mm = 67%)
63 mm to 40 mm	3000 g (consisting of 50 mm to 40 mm = 50% and 63 mm to 50 mm = 50%)
80 mm and larger	3000 g

• Take proper weight of sample from each fraction and place it in separate containers for the test.

Procedure

1. Take individual samples in a wire mesh basket and immerse it in the solution of sodium sulphate or magnesium sulphate for not less than 16 hours nor more than 18 hours, in such a manner that the solution covers them to a depth of at least 15 mm.
2. After completion of the immersion period, remove the samples from solution and allow it to drain for 15 minutes and place it in drying oven.
3. Dry the sample until it attains a constant mass and then remove it from oven and cool it to room temperature.
4. After cooling again immerse it in the solution as described in step-1.
5. The process of alternate immersion and drying is repeated until the specified number of cycles as agreed between the purchaser and the vendor is obtained.
6. After completion of the final cycle and after the sample has been cooled, wash it to free from sodium sulphate or magnesium sulphate solution. This may be determined when there is no reaction of the wash water with barium chloride.
7. Then dry each fraction of the sample to constant temp of 105 to 110⁰C and weigh it.
8. Sieve the fine aggregates over the same sieve on which it was retained before test.
9. Sieve the coarse aggregate over the sieve shown below for the appropriate size of particles.

Size of Aggregate	Sieve used to determine loss
63 mm to 40 mm	31.5 mm
40 mm to 20 mm	16.0 mm
20 mm to 10 mm	8.0 mm
10 mm to 4.75 mm	4.0 mm

 Report

The result should be reported giving the following particulars

• Type of solution used for the test
• Weight of each fraction of sample before the test.
• Material from each fraction of the sample passing through the specified IS sieve, expressed as a percentage by weight of the fraction.
• In the case of particles coarser than 20 mm size before the test, the number of particles in each fraction before the test and the number of particles affected classified as to the number disintegrating, splitting, crumbling , cracking, flaking etc.

Reference

• IS-2386 (Part-5)-Methods Of Test For Aggregates For Concrete (Part-5-Soundness)