Table of Contents
In this article, we are discussing the soundness test of cement.
1. Introduction
The soundness of cement may be defined as the property of which cement resists or withstands the expansion due to slow or delayed hydration of free lime, magnesia and calcium sulphate.
In other words, soundness can be defined as the ability of the cement to retain its volume after it has hardened.
The soundness test is an important test that is necessary for evaluating the quality of cement to be used in the construction. This is because unsound cement adversely affects the quality and strength of the construction.
Soundness also directly affects the durability of the structure. The soundness test of cement is mostly conducted by Le-Chatlier’s Method.
2. General Test Procedure of Soundness Test of Cement
The general test procedure of the soundness test on cement has been briefly discussed below.
Objectives
1. To determine the soundness of cement.
2. To ascertain the quality and durability of the cement works.
Apparatus Required
1. Le-Chatelier’s Mould
2. Cement
3. Glass Sheets
4. Mixing Pans
5. Trowel
6. Weight
Procedure
The procedure of the soundness test includes the following series of steps:
1. The Le-Chatelier’s apparatus, as well as the glass sheets, are cleaned and duly oiled before the commencement of the test.
2. Then, the cement paste specimen with the standard consistency is prepared.
3. The prepared cement paste is filled in the Le-Chatelier mould carefully.
4. The filled mould is then covered with another glass plate and then the weight is placed on the cover plate.
5. The entire arrangement is submerged in water at a temperature of 27 ± 2 degrees Celsius for about 24 hours.
6. The entire assembly is then removed from the water and the distance between the mould edges is measured. Let the distance be noted as L1.
7. Then, the mould is again submerged in water and is boiled. It is then allowed to cool down at room temperature.
8. The moulded edge is again measured. Let the distance be denoted as L2.
Calculation
The soundness of Cement = L1 – L2
The value obtained should not be greater than 10mm in most of the cases (such as OPC, PPC, Rapid Hardening Cement etc).
Precautions
1. Apparatus must be handled with care.
2. During the boiling process, care must be taken so that the water level remains above the height of the mould.
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