To determine soundness of cement by Le-Chatelier’s apparatus

TITLE:

To determine soundness of cement by Le-Chatelier’s apparatus

PRIOR CONCEPTS:

Types of cement, ingredient of cement, normal consistency of cement.

NEW CONCEPTS

Propositions 1: Soundness of Cement

The cement is said to be sound when the percentage of free lime and magnesia is with in specified limits .

These materials expand in the structure and thus the concrete or mortar also expand, causing unequal expansion of paste.

Propositions 2: Soundness of cement

Disintegration of cement compound is determined by Le- Chatelier apparatus.

LEARNING OBJECTIVES:

Intellectual Skills:

  1. To decide the suitability of given cement sample.

Motor Skills

  1. To fill up the Le-Chatelier mould and placing glass plate as per procedure.
  2. To measure expansion of the pointer.

Diagram

APPARATUS AND MATERIALS:

  1. Le-Chatelier apparatus
  2. Weighing balance accurate up to 0.1gm
  3. Water bath with electric heating arrangement
  4. Measuring cylinder
  5. Glass plates
  6. Stop watch
  7. Trowel
  8. Tray

Materials:

  1. Cement sample
  2. Water

STEPWISE PROCEDURE ( AS PER IS : 4031):

  1. Prepare a cement paste formed by gauging cement with 0.78 times water required to give a paste of standard consistency. The gauging time should not be less than 3 minutes nor greater than 5 minutes.
  2. Oil the inner surface of the mould. Place the mould on a glass sheet and fill it with cement paste, taking care to keep the edges of the mould gently together. Cover the mould with another piece of glass sheet and peace a small weight on this covering glass sheet and immediately submerge the whole assembly in water at a temperature of 27°Cand keep it for 24 hours.
  3. Take out the assembly from water after 24 hrs. Measure the distance between the indicator points and record it (D1)
  4. Submerge the mould again in water and bring the water to boiling in 25 to 30 minutes and keep it boiling for three hours.
  5. Remove the mould from the water. Allow it to cool and measure the distance between the indicator points and record it ( D2 ).
  6. Three samples should be tested and average of the results should be reported.

OBSERVATIONS:

1. Types and brand of cement …………………………………………………………

2. Grade of cement ……………………………………………………………………….

  1. Weight of cement sample – ( Wc) =… gm
  2. Water required for standard consistency ( P ) =… %
  3. Water added to the cement sample =0.78 x P x Wc =……………………………………..

For Soundness test of cement:

RESULTS:

The expansion of the cement in the Le Chatelier apparatus is found to be mm

BIS REQUIREMENTS:

As per IS:269, when tested by Le Chatelier method, un -aerated ordinary portland cement shall not have an expansion of more than 10 mm.

CONCLUSION:

Since the average expansion of cement is………… mm here Cement sample is……………………

(sound /unsound.)

 

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