Stability testing methods in addition to the test cake method, as well as Reye clamp method and length measurement method. Although the latter two methods have a quantitative value limit, but the method complicated, complex play is also poor; and trial law cake with simple equipment, easy operation, sensitive, and direct observation, the complex play of good range of benefits, so far still as a national standard methods. Lian boiling cooking method can only detect the damaging effects of free calcium oxide. Since the fire burned more slowly than magnesium oxide, calcium oxide hydration rate, and therefore can not be found with boiling cooking method cement insecurities caused by the magnesium oxide, only by autoclave test temperature, high pressure, in order to determine this phenomenon. The insecurities caused by sulfur trioxide, only cold bread method, immersion method to be tested, the upcoming trial on the cake after water curing 28d 20 ℃ ± 3 ℃ of cement bricks, check for instability phenomenon. Because when the temperature exceeds 60 ~ 70 ℃, it will not form a volume expansion generated sulphoaluminate. Setting time is measured using standard consistency of cement paste at a certain temperature and humidity conditions. From the date when water cement to paste the test needle sank 0.5 ~ 1 Omm from the floor until the time, the time required for the initial setting time of cement grade, then the paste begins to lose plasticity;. To test needle net sink 1. Omm slurry until the time does not exceed the time required for the final setting time, then paste completely lost plasticity and entered the hardening stage. _ _ Henan cement mortar cement provided by Wuhan Hongshan District of Wuhan pavilion cement operation. Hongshan District of Wuhan pavilion cement business unit (www.whltsn.com) (www.hbltsn.com) strong, credible, in Wuhan of cement and related products industry has accumulated a large number of loyal customers. The company better work attitude and constantly improving innovative ideas will lead Wuhan cement into the brilliant and you work for a better future!