Le-Chatelier Apparatus:
Le-Chatelier apparatus consist of a small split cylinder of spring brass of thickness 0.5 mm, forming a mould 30 mm high. Two indicators with pointed ends are attached on both sides of the split (which should not be more than 0.5 mm). The distance from these ends to the center of the cylinder is 165 mm.
In this test, 100 gm of cement is taken and 0.78 P water is added, where P is the percentage of water required for normal consistency paste. It is mixed thoroughly for about three minutes. Erase air bubble from the cement paste, if any. Cement paste is then filled into the mould, resting on a glass plate (within five minutes from the instant water is added). A mould is then smoothened and covered with another glass plate. A little weight is placed on the top and whole assembly is instantly submerged in water at a temperature of 27oC to 32oC for 24 hours. Then the mould is removed from water and the distance separating the indicator points is measured. The overall assembly is submerged again in water and the water is heated till it reaches the boiling point in 25 to 30 minutes. The mould is kept in boiling water for three hours. After that the mould is taken out of water and allowed to cool. After cooling, the distance among pointers is again measured. The difference between these two measurements represents the expansion of cement. For ordinary Portland cement, rapid hardening cement and low heat cement the expansion shall not be more than 10 mm.
Figure: Le-Chatelier Apparatus