SOUNDNESS TEST OF AGGREGATESby use of Sodium Sulfate or Magnesium Sulfate

• ASTM C-88• AASHTO T104

Soundness Test of Aggregates

- This test is used to determine the resistance of coarse and fine aggregates to weathering action and to judge the durability of the aggregates.

- It is submerges an aggregate sample in a sodium sulfate or magnesium sulfate solution.

- Also called “Weathering Test”

APPARATUS

500g Balance

APPARATUS

5000g Balance

APPARATUS

Sieve Tray ( use Specification E11)

APPARATUS

Drying Oven

APPARATUS

WIRE MESH BASKET

APPARATUS

Container

APPARATUS

SODIUM SULFATE/MAGNESIUM SULFATE

PROCEDURESoundness Test for

fine and Coarse Aggregates

NOTE:

•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.

Sample Size5,000 ± 300 g 2‐½ to 1‐½ in.1,500 ± 50 g 1‐½ to ¾ in.1,000 ± 10 g ¾ to ⅜ in.300 ± 5 g ⅜ in. to No. 4

1. Take the individual samples in a wire mesh and immerse in the solution.

-16 to 18 hrs - 70 ± 1.5 ºF (20.3-21.9ºC) - cover them to the depth atleast 15mm

2. Remove and drain sample for 15 ± 5 minutes. Place it in drying oven.

3. Dry sample the to constant weight at 230 ± 9 ºF (20-25 ºC).Then remove it from oven

and cool it to room temperature.

4. Repeat process for specified no. of cycles of immersion and drying.

5. After completion of the final cycle and after the sample has been cooled,wash it to free from sodium sulphate or magnesium sulphate solution.

 (Use barium chloride)

6. Then dry each fraction of the sample to constant temp of 105 to 1100C and weigh it.

7. Sieve the aggregates over the size particle requirement.

COMPUTATION

Original mass of sample: Initial MassMass of particles after test: Final Intact MassPercent Loss %

Percent Loss = (Initial Mass – Final Intact Mass) X 100%

Initial Mass

Result: BEFORE(top), AFTER(Below)

COMMON ERROR

Improper temperature of solution

Improper solution concentration(specific gravity)

Insufficient drying timesNot all salt removed by washingFurther breakdown of particles while sieving

ISSUES IN

SULFATE SOUNDNESS TEST

sulfate soundness tests can serve as a useful first evaulation of a particular aggregate or as a confirming test for an aggregate with a long test and performance record. However, issues to actual performance prevent the test from being meaningful beyond this:

APPLICABILITY

VARIABILITYRELATION TO PAVEMENT PERFORMANCE