This document describes a test to determine the resistance of aggregates to disintegration from saturated sodium sulfate or magnesium sulfate solutions. The soundness test involves immersing coarse aggregate samples in a sodium sulfate solution for 24 hours, then drying and cooling them in cycles over 10 days. The percentage loss is calculated by comparing the initial and final weights, with aggregates showing less than 25% loss considered suitable for use in road pavement due to sufficient resistance to weathering.

1. Soundness Test of
Aggregates
 This test is used to determine
the resistance of aggregates to
disintegrate by saturated
solutions of sodium sulphate
or magnesium sulphate.
 This Test is easy but time
consuming.
Introduction:

2. Objective:
 To determine the
weathering action
of aggregates.

3. Apparatus & Materials Required:
 Sample container
 Weighing
machine
 Drying oven
 Immersion tank
 Coarse Aggregates
 Sodium
Sulphate(Na2So4)
Salt MgSo4 Na2So4
Anhydrous 350 gm 215 gm
Crystalline 1400 gm 700 gm
Minimum Mass of Salt Per Liter of Water

4. Fig: Sample Container,
magnesium sulphate and
sodium sulphate

5. Fig: Sodium Sulphate Fig: Sample Container

6. Procedure:
 1 kg of Coarse aggregates is taken as
sample.
 Sample is immersed in the
sodium sulphate solution for 24
hours.
 It is taken out from solution then, dried in
oven and cooled.
 Immersion, drying and cooling process is
repeated for 10 complete cycles.
 Finally retained weight on sample

7. Observation & Calculation:
Percentage loss = *100 %
W0-W1
W0
Where, w0 = initial wt of sample
w1= final retained wt on sample
container after 10 cycles
For example:
Let w0=100 gm
w1= 82 gm
Then, percentage loss = [(100-82)/100] *100 %
= 18 % which is less than 25%

8. Table of soundness test of aggregate

9. Discussion & Conclusion:
Since no. of cycles is 10 and re-agent
used is Na2So4 so the maximum
percentage loss is 25%.
When the percentage loss is greater
than 25% then, this test shows that
aggregate undergoes weathering process
which ultimately decreases bearing
strength. Hence, such aggregates cannot
be used in road pavement.
Aggregate having percentage loss less
than 25% is used in road pavement.