4) Without disturbing or jarring the dilatometer, change to the +30℃ bath, so than the top of the specimen is at least 50mm below the liquid level of the bath. Maintain the temperature of the bath in the range form 28 to 32℃±0.2℃ until the temperature of the specimen reaches that of the bath as demoted by no further changes in the measuring device reading over a period of 5 to 10min.Record the actual temperature and the measuring device reading.