Table of Contents
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:
- To decide the suitability of given cement sample.
Motor Skills
- To fill up the Le-Chatelier mould and placing glass plate as per procedure.
- To measure expansion of the pointer.
Diagram
APPARATUS AND MATERIALS:
- Le-Chatelier apparatus
- Weighing balance accurate up to 0.1gm
- Water bath with electric heating arrangement
- Measuring cylinder
- Glass plates
- Stop watch
- Trowel
- Tray
Materials:
- Cement sample
- Water
STEPWISE PROCEDURE ( AS PER IS : 4031):
- 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.
- 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.
- Take out the assembly from water after 24 hrs. Measure the distance between the indicator points and record it (D1)
- Submerge the mould again in water and bring the water to boiling in 25 to 30 minutes and keep it boiling for three hours.
- Remove the mould from the water. Allow it to cool and measure the distance between the indicator points and record it ( D2 ).
- Three samples should be tested and average of the results should be reported.
OBSERVATIONS:
1. Types and brand of cement …………………………………………………………
2. Grade of cement ……………………………………………………………………….
- Weight of cement sample – ( Wc) =… gm
- Water required for standard consistency ( P ) =… %
- 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.)