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The result of the chemical reaction of limestone, clay and other additives under intense heat treatment in a furnace, which usually contains calcium silicate and aluminate. To produce gray clinker, raw materials such as iron oxide, clay, etc. are combined with limestone.
This type of cement has the largest share of production in the country. This type of cement has low hydration heat and must be resistant to moderate sulfate attacks. Type 2 cement is used in groundwater systems with a high percentage of sulfate.
This type has 15% pozzolan. Pozzolani cement is used in large structures and its advantage is its low heat hydration type. Although its short-term resistance is lower than other types, its resistance increases in the long run. The most important characteristic of this type is its high resistance to chemical attacks against chlorine and sulfate. Concrete made from this cement has low permeability, high durability and good resistance to chemical attacks.
This cement is similar to Portland Cement 1-325 in physical properties and chemically similar to pozzolanic Portland cement and has similar uses for this type of cement.
Portland cement has a high softness that causes more water absorption and creates more suitable conditions to increase the strength of cement mortar so that the growth of resistance of this type of cement begins with a suitable slope and continues after 28 days and over time to the highest possible level. It arrives. Due to the high softness of cement and filling the pores between the sand, which as a result provides the required filler and reduces the deep cracks and micro-cracks in the cement surfaces and prevents water penetration.
Also, this type of cement has a good setting time, which creates a suitable time opportunity for optimal use of cement mortar. Increasing the wear resistance of cement surfaces due to the presence of higher silica in this cement has a direct effect on reducing physical erosion and increasing the life of cement parts. It should be noted that due to the low heat resulting from the reaction of water with this cement, the resulting heat is gradually removed at the same time as the cement mortar hardens and prevents cracking of the surfaces of the cement piece. The use of this cement eliminates the undesirable phenomenon of dandruff in the cement part and prevents the carbonation of concrete, as well as reduces the phenomenon of water descaling and shrinkage of concrete.
In this type of cement, if the percentage of additives is in the range of 20%, it is called composite Portland cement, and if the percentage of additive composition is in the range above 20%, it is called special composite Portland cement.