(2) Strength: The strength of cement should meet the national standards.
(3) Fineness: refers to the thickness of cement particles.
The finer the particles, the faster the hardening and the higher the early strength.
(4) Setting time: The time required for cement to start setting after mixing with water is called initial setting time.
The time from adding water and stirring to the completion of coagulation is called the final coagulation time.
The initial setting time of portland cement is not earlier than 45 minutes, and the final setting time is not later than 12 hours.
(5) Hydration heat: The interaction between cement and water will produce exothermic reaction. In the process of cement hardening, the heat released continuously is called hydration heat.
(6) Volume stability: refers to the performance of uniform volume change of cement during hardening.
There are many impurities in cement, which will produce uneven deformation.
(7) Standard consistency: refers to the consistency when the cement paste has certain resistance to the sinking of the standard test bar.
Cement is an important building material. Mortar or concrete made of cement is durable and widely used in civil construction, water conservancy, national defense and other projects.