DETERMINATION OF MOISTURE CONTENT BY THE REACTION OF CALCIUM CARBIDE WITH THE FREE WATER OF THE SOIL (IS: 2720-PART-2)

Purpose

The purpose of this test is to quickly determine the moisture content of the soil, without waiting for the moisture to evaporate.


soil sample

About 6 grams of soil sample is required for this test. Sand does not require special preparation. Coarse powders can be ground and powdered. Adhesive and plastic clays and materials are tested by adding ste1 balls to pressure vessels.

devices

1. Rapid Moisture Meter


Rapid Moisture Meter (Used for Testing Soil Water Content)
Rapid Moisture Meter (Used for Testing Soil Water Content)
Various parts of rapid moisture meter
Various parts of rapid moisture meter

Process

  1. Equipment needed for testing includes a metal pressure vessel with clamps for the sealing cup and a gauge calibrated to percentage water. A counterpoint balance, a scoop for measuring calcium carbide, and three steel balls of 12.5 mm diameter and one steel ball of 25 mm diameter.
  2. Set the balance and place the sample in the pan until the mark on the balance arm mass coincides with the index mark.
  3. Unscrew the clamping screw to remove the U-clamp from the cup. Raise the cup. Clean the cup and body.
  4. Hold the body horizontally and gently deposit a level scoopful of calcium carbide halfway inside the chamber. Then put the chamber down without disturbing the calcium carbide charge and transfer the weighing clay from the pan to the bowl as above.
  5. Holding the cup and chamber almost horizontally, bring them together, without disturbing the sample or the calcium carbide, round the U clamp and clamp the cup tightly in place.
  6. With the gauge facing down, shake the moisture meter vigorously up and down for 5 seconds, then turn it quickly so the gauge is facing up, giving the body of the moisture meter a tap to make sure all the contents of the cup fall in
  7. Hold the Rapid Moisture Meter face down, shake again for 5 seconds, then turn it upside down from the gauge and tap. Wait for a minute. Repeat this for the third time. Once again quickly turn the moisture meter upside down and shake the gas up and down to cool it. Rapidly turn the moisture meter with the gauge facing upwards, and when the needle comes to rest then dial horizontally at chest height, taking the reading. The reading on the meter is the percentage of water based on wet mass.
  8. Alternatively, three small steel balls can be placed in the cup with clay and the larger one in the body with an absorbent and seal the unit as usual. Hold the Rapid Moisture Meter vertically so that the contents in the cup fall into the body. Now holding the unit horizontally, rotate it for 10 seconds so that the balls roll around the inside circumference of the body. Rest for 20 seconds. Repeat the rotation – rest cycle until the gauge reading is stable (usually this takes 4 to 8 minutes). As always, focus on reading.
  9. Finally release the pressure slowly (away from the operator) by unscrewing the clamp screw and taking the cup out, empty the contents and clean the tool with a brush.
  10. Rapidly calculate the amount of water (W) on the dry mass from the amount of water (M) obtained based on the wet mass as the reading on the moisture meter:

W = [M/(100-M)]*100

Where,

W = percent water content of dry mass

M = percentage water content of wet mass

Reference

IS 2720 (Part II) – 1973

Er. Mukesh Kumar

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Er. Mukesh Kumar is Editor in Chief and Co-Funder at ProCivilEngineer.com Civil Engineering Website. Mukesh Kumar is a Bachelor in Civil Engineering From MIT. He has work experience in Highway Construction, Bridge Construction, Railway Steel Girder work, Under box culvert construction, Retaining wall construction. He was a lecturer in a Engineering college for more than 6 years.