Take 400gm of Cement and find its standard consistency for Cement soundness test
Place the lightly oiled Le- Chatelier mold on a lightly oiled glass sheet
Prepare a cement paste formed by gauging cement with 0.78 times the water required to give a paste of standard consistency.
Fill the Le-Chatelier mold with this cement paste made in step (iii) of the procedure.
Cover the mold on the top with another piece of a lightly oiled glass sheet.
Place a small weight on this covering glass sheet and immediately submerge the whole assembly in the water at a temperature of 27° to 32° degree Celsius and keep it there for 24 hours.
Measure the distance between the indicator points. Submerge the mold again in water. Bring to boiling point in about 25-30 minutes and kept it boiling for 3 hours.
Removal, the mold from water, allows it to cool and measure the distance between the indicator points. The difference between these two measurements represents the expansion of cement.
At 24 ± t h after molding, the specimens shall be removed from the moist atmosphere, measured for length, and placed in the autoclave at room temperature in a rack so that the four sides of each specimen shall be exposed to saturated steam. For soundness of cement test From IS Code 4031 Part 3 Cl 6.3
The autoclave shall contain enough water to maintain an atmosphere of saturated steam vapor during the entire period oftest. From IS Code 4031 Part 3 Cl 6.3
Ordinarily; 7 to 10 percent of the volume of the autoclave shall be occupied by water.
To permit air to escape from the autoclave during the early portion of the heating period, the vent valve shall be left open until steam begins to vanish.From IS Code 4031 Part 3 Cl 6.3
The valve shall then be closed, and the temperature of the autoclave shall be raised at such a rate as will bring the gauge pressure of the steam to 2.1 MPa in I to Ii h from the time the heat is turned on.. From IS Code 4031 Part 3 Cl 6.3
The 2.1 ± O'lMPa pressure shall be maintained for 3 h. At the end of 3 hours period, the heat supply shall be shut off, and the autoclave cooled at a rate such that the pressure will be less than 0.1 MPa at the end of the hour, and any pressure remaining shall be slow-released by partially opening the vent valve until atmospheric pressure is attained.. From IS Code 4031 Part 3 Cl 6.3
The autoclave shall then be opened, and the test specimens immediately placed in water,
The temperature of which is above 90°C.
The water surrounding the bars shall·then be cooled at a uniform rate by adding cold water so that the temperature of the water shall be lowered to 27 ± 2°C in 15 min.
The water surrounding the specimens shall then be maintained at 27 ± 2°C in 15 min when the samples shall be surface-dried, and their lengths measured again. From IS Code 4031 Part 3 Cl 6.3
Expansion within permissible limits: If the expansion of the cement paste during the soundness test falls within the specified limits set by the relevant standards, it indicates that the cement is sound and does not have any significant potential for delayed expansion or unsoundness. The cement meets the requirements for dimensional stability.
Excessive expansion: If the expansion of the cement paste exceeds the permissible limits, it suggests the presence of unsoundness in the cement. Excessive expansion may lead to cracking, distortion, or loss of strength in concrete or other cement-based products. It indicates that the cement may not be suitable for use in applications where dimensional stability is crucial.
No expansion or contraction: In some soundness test methods, such as the autoclave test, no expansion or contraction is considered acceptable. If the cement paste shows no significant change in dimension after the test, it indicates that the cement is sound and does not exhibit any potential for expansion or contraction issues.