Soundness test

soundness test

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(Na 2 So 4 ) Salt MgSo 4 Na 2 So 4 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 container is noted.

7. Observation & Calculation: Percentage loss = *100 % W -W 1 W Where, w = initial wt of sample w 1 = 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 Na 2 So 4 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.

10. Any Questions???