Introduction and Brief History
Cement is a building material used as a binder. It binds other building material additives and sand together. Cement has different properties when we change its chemical composition. It is obtained by mixing limestone and clay, burning it, and grinding it into a fine powder. Here we are discussing the different types of cement.
All types of cement are divided into two categories: hydraulic cement and non-hydraulic cement. Hydraulic cement hardens by hydration in the presence of water, while non-hydraulic cement hardens in the absence of water.
Hydraulic cement is commonly referred to as Portland cement when it hardens due to its similarity to Portland stone found near Dorset, England. The name was first used in his patent in 1824 by Joseph Aspdin of Leeds, England.
In the past, different types of cement were only found by varying the relative proportion of the oxide composition. Over time, new materials such as clinker additives at the time of grinding, the use of new raw materials have led to the manufacture of a new type of cement.
The different types of cement according to Indian standards are-
Types of Cement and Their Uses in Construction
1. Ordinary Portland Cement (OPC)
Ordinary Portland cement is the most common type of cement suitable for all general concrete structures. This cement is also known as basic Portland cement and is best suited for general concrete construction where there are no sulfates in the soil or groundwater.
Types of Ordinary Portland cement
• Ordinary Portland cement of OPC-33 quality
• Ordinary Portland cement of OPC-43 quality
• Ordinary Portland cement of OPC-53 quality
Here types 33, 43, and 53 indicate the strength of the cement after 28 days according to the IS code. Nowadays, OPC-33 grade cement is almost obsolete as higher-grade cement comes to market. One of the main advantages of OPC cement is that it develops strength faster. The initial setting time of OPC cement should not be less than 45 minutes and the final setting time should not exceed 10 hours.
Applications of Ordinary Portland Cement (OPC)
-It is used for general construction purposes.
-It is also used in most masonry works.
2. Portland Pozzolana Cement (PPC)
Portland pozzolana cement is made by grinding pozzolana clinker with Portland cement. It is also made by adding pozzolana with the addition of gypsum or calcium sulfate, or by thoroughly and evenly mixing Portland cement and fine pozzolana. The proportion of pozzolana can vary between 10 and 25% by the weight of the cement.
Portland pozzolana cement produces less heat of hydration, and compared to ordinary Portland cement, this cement has high resistance to various chemical attacks on concrete and therefore is widely used. PPC cement is suitable for the following conditions: For structures at the water’s edge or for marine structures such as dams, bridge piers, and thick foundations where bulk concrete is used, also used for systems of sewers such as sewers.
The main use of pozzolana is to replace part of the cement in a mixture and this can lead to significant savings, especially when the materials are available locally. From a technical point of view, PPC has considerable advantages over OPC if it is produced using the optimum proportion of fly ash.
Applications of Portland Pozzolana Cement (PPC)
-It is used for general construction purposes.
-Mass Concreting
-Foundations and Basements
-Water Retaining structures
3.Rapid Hardening Cement
The Rapid hardening cement achieves high strength in the first days; it is used in concrete where forms are removed at an early stage and are similar to ordinary Portland cement (OPC). This cement has increased lime content and contains higher c3s content and finer grinding, resulting in higher strength development than early-stage OPC.
This cement has the same chemical composition as ordinary Portland cement but is ground more finely. Its 24-hour strength is almost equal to that achieved by ordinary Portland cement after 3 days. The use of this cement allows early removal of the formwork thus directly affecting the saving of time and money.
Applications of Rapid Hardening Cement
-Road Repair works
-In pre-fabricated concrete construction
-In cold weather concrete to reduce frost damage
-Where formwork is to be removed quickly.
-Bridges Construction
4. Quick setting cement
As the name suggests, this cement sets very early. This early setting property is achieved by limiting the gypsum content to no more than 3 percent and accelerators are added at the time of grinding the clinker. This cement must be mixed, placed, and compacted very early. It is mainly used in underwater construction where pumping is involved. It is also used in grouting operations.
The difference between quick-setting cement and Rapid setting cement is that quick-setting cement sets earlier. At the same time, the rate of strength gain is similar to that of ordinary Portland cement, while Rapid hardening cement quickly gains strength. The formwork in both cases can be removed earlier.
Applications of Quick setting cement
-It is used in underwater construction.
-It is also used in rainy & cold weather conditions.
-It is used a higher temperature where water evaporates easily.
-Used for anchoring or rock bolt mining and tunneling
5. Low Heat Cement
It is a type of cement that generates a low heat of hydration when it sets. Some of the chemical composition of ordinary Portland cement is changed to reduce the heat of hydration. Low-temperature cement is suitable for massive concrete construction such as gravity dams, as the low heat of hydration, prevents concrete from cracking from heat.
Due to its high resistance to chemical corrosion, it is widely used for floors and surfaces in chemical plants; Due to its high strength and wear resistance, this cement is also used in dams, wind turbine bases, and large concrete foundations and rafts. The initial setting time is longer than with OPC.
Applications of Low Heat Cement
-It is used for the construction of dams’ large footing, large raft slabs, and wind turbine plinths.
-It is also used for the construction of chemical plants.
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