Difference between OPC and SRC

OPC and SRC are two types of cement commonly used in the construction industry. While both serve as vital materials in various applications, they differ significantly in terms of composition, properties, and suitable uses.

Composition and Production

OPC (Ordinary Portland Cement) is the most widely used type of cement globally. It is produced by grinding together clinker, gypsum, and other materials such as limestone, fly ash, and blast furnace slag. The resulting powder is then mixed with water to form a paste that hardens over time into a strong and durable material. The composition of OPC primarily includes calcium silicates, which provide high strength and good workability.
On the other hand, SRC (Sulphate Resistant Cement) is a specialized type of cement designed to resist the harmful effects of sulfates present in soil and water. SRC is produced by adding extra amounts of calcium aluminate and calcium sulfate to OPC during the manufacturing process. These additional compounds react with the sulfates to form stable compounds that are less harmful to the cement. This special formulation makes SRC suitable for environments where sulfate attack is a concern.

Properties and Characteristics

OPC is known for its high strength, good workability, and relatively low cost. It is commonly used in the construction of buildings, bridges, roads, and other structures. The high compressive strength of OPC makes it an ideal choice for structural applications where durability and load-bearing capacity are crucial.
In contrast, SRC is characterized by its high resistance to sulfates and other chemicals, as well as its low heat of hydration. These properties make SRC particularly suitable for use in marine environments, underground structures, and other locations where sulfates are present. The resistance to sulfate attack ensures that the concrete maintains its integrity and durability over time, even in harsh conditions.


The primary difference between OPC and SRC lies in their resistance to sulfates. OPC is susceptible to damage from sulfates, making it less suitable for environments where sulfate exposure is high. However, its high compressive strength and versatility make it a popular choice for a wide range of construction projects, including residential and commercial buildings, highways, and bridges.
SRC, on the other hand, is specifically designed to resist sulfate attack. This makes SRC the preferred choice for use in areas near the coast, in regions with high groundwater levels, or in any location where sulfate exposure is a concern. SRC is commonly used in marine environments, such as piers and docks, as well as in underground structures like foundations and sewage systems.

Mechanical Strengths

Another notable difference between OPC and SRC is their mechanical strengths. OPC typically has a higher compressive strength than SRC, meaning it can withstand more stress before breaking. This makes OPC ideal for applications that require strong, load-bearing structures.
However, SRC has a higher flexural strength, which means it can withstand more bending stress without breaking. This property makes SRC a better choice for applications where the material will be subject to bending or flexing, such as in beams, columns, and other structural elements that require flexibility.



In summary, OPC and SRC are two types of cement with distinct properties and applications. OPC, with its high strength and low cost, is the most widely used cement in the world, suitable for a variety of general construction projects. SRC, designed to resist sulfates and other chemicals, is commonly used in marine environments and underground structures where sulfate attack is a concern. The choice between OPC and SRC depends on the specific requirements of the project, including the environmental conditions and the structural demands.
Understanding the differences between OPC and SRC is crucial for selecting the right cement type for your construction needs, ensuring durability, safety, and longevity of the structures built.