Calcium Carbide Method For Water Content Determination In Soil

As we know the water content or moisture content is the amount of water in the soil and it is determined by various methods like the Oven Drying Method, Alcohol Method, Sand Bath Method, Calcium Carbide Method, Pycnometer Method, and Torsion Method.

In this article, we are going to talk about only the Calcium Carbide Method for water content determination in soils.

Calcium Carbide Method | Rapid Moisture Meter Method

The calcium carbide method is a rapid method of determining water content in the soil.

The calcium carbide method work on the principle of the chemical reaction which is when the water reacts with calcium carbide (CaC2) and releases the acetylene gas (C₂H₂).

CaC₂ + 2H₂O = C₂H₂ + Ca(OH)₂

And the pressure exerted by the acetylene gas helps in the determination of the water content of the soil.

This method is used in the laboratory as well as in the field too.

The calcium carbide method is also known as the rapid moisture meter method.

Apparatus And Materials Requirement

Here is the list of apparatus and materials which are required for determining water content in the soil through the calcium carbide method.

1. Moisture Tester– It is an instrument used in the calcium carbide method.
2. Dial Gauge– Use for recording pressure. It is attached to the moisture tester
3. Scoop– Use for measuring Calcium Carbide.
4. Steel balls– Around 4 steel balls are used
5. Balancing Machine– Use for measuring soil sample
6. Reagent Of Calcium Carbide
7. Metallic bottle

More Read- Oven Drying Method Of Water Content Determination Of Soil

Preparation of Sample For Calcium Carbide Method

In the case of the sample of sand, there is no required steel ball in the metallic cylinder with calcium carbide.

But in the case of cohesive and plastic soils, the steel balls are placed inside the metallic cylinder for breaking down the cohesive and plastic soils.

6 grams of sample is taken for this test.

Procedure for Calcium Carbide Moisture Test

1. First, we measure 6 grams of soil sample and put it into the metallic cylinder bottle that has already calcium carbide in it.

2. After putting the sample soil into a metallic bottle we insert 4 steel balls inside the metallic bottle and sealed the metallic bottle by using clamps.

3. Now we shake the metallic bottle in order to get a complete mixup of the soil sample and calcium carbide.

4. The calcium carbide reacts with the water present in the soil sample and produces acetylene gas (C₂H₂).

5. The acetylene gas produces pressure inside the metallic bottle and this pressure is recorded by the Dial Gauge.

6. From the scale of the dial gauge the water content based on the total mass is determined.

Note- The calcium carbide should not be exposed to the atmosphere because it is susceptible to the absorption of moisture.

More Read- Radiation Method For Water Content Determination In Soil

Calculation Of Calcium Carbide Method

The calculations of water content are done from the following equation-

The formula for the calculation of water content through the Calcium Carbide Method is w= (M / 100-M).100.

Here M is the weight of the sample.

Result- Average water content of the soil sample is —

More Read- Sand Bath Method For Water Content Determination Of Soil

More Read- Alcohol Method Of Water Content Determination Of Soil

Frequently Asked Questions(FAQ)