Objective

For determination of linear shrinkage of soil

Reference Standard

IS: 2720(Part 20)-1966- Methods of test for soils: Determination of linear shrinkage.

Equipment / Apparatus

• Mould
• Oven

Preparation sample

A sample weighing 150g from thoroughly mixed portion of bulk material passing 425 micron IS sieve is prepared.

Procedure

1. The mould is thoroughly cleaned and a thin film of grease is  applied to its inner walls.
2. Above soil sample is mixed thoroughly with distilled water, using palette knives, until the mass becomes homogeneous.
3. The thoroughly mixed soil-water paste is placed in the mould such that it is slightly above the sides of the mould.
4. Then the mould with the soil paste is dried in the oven maintained at a temperature of 105 to 110⁰C.
5. After complete drying, the mould and soil is cooled and the mean length of the soil bar is measured.

Calculation

The linear shrinkage of the soil is to be calculated as a percentage of the original length of the specimen from the following formula:

Linear shrinkage =[1- (Length of oven dried specimen / Initial length of specimen)]  × 100

Report

The linear shrinkage of the soil is to be reported to the nearest whole number

Safety & Precautions

• Clean the sieves with the help of a brush, after sieving.