Moisture exudation testing of compacted soil samples is a testing requirement of ASTM D2844, AASHTO T190 and CTM 301. To perform this test, a compressive load is applied to a cylindrical, compacted soil sample until a certain amount of moisture is displaced from the bottom of the specimen. At this point, the load is recorded. This test requires a compression testing machine and a special exudation fixture . Older exudation fixtures contain a circle of six contact points on the base plate. When contacted by water, these points will switch-on a light on the indicator box (pictured at right). Newer exudation fixtures contain an additional solid ring on the base plate and a corresponding light on the indicator box. This ring detects free flowing water coming from underneath the mold.