The main difference between Ordinary Portland Cement (OPC) and Sulphate Resistant Cement (SRC) lies in their resistance to sulfate attacks. Sulfates are chemical compounds found in soil or water that can react with certain cement compounds, potentially leading to the deterioration of concrete structures. Here are the key distinctions between the two types of cement:
1. Composition:
– Ordinary Portland Cement (OPC): OPC is the most common type of cement used in general construction. It typically contains clinker, gypsum, and small amounts of other additives.
– Sulphate Resistant Cement (SRC): SRC, as the name suggests, is formulated with additional measures to enhance its resistance to sulfate attacks. It contains lower amounts of the mineral compound tricalcium aluminate (C3A) than OPC, as C3A is more susceptible to sulfate reactions.
2. Sulfate Resistance:
– OPC: While OPC has good overall performance in many construction applications, it has moderate resistance to sulfate attacks. In severe sulfate environments, OPC may be vulnerable to deterioration and cracking over time.
– SRC: SRC is specifically designed to provide higher resistance to sulfate attacks, making it suitable for use in areas where the soil or water has a high sulfate content. It significantly reduces the risk of sulfate-induced damage to concrete structures.
3. Applications:
– OPC: OPC is widely used in various general construction projects, including residential buildings, commercial structures, and non-aggressive environmental conditions where sulfate exposure is not a significant concern.
– SRC: SRC is specifically recommended for areas with a higher risk of sulfate attacks, such as coastal regions, sewage treatment plants, underground structures, and any environment with elevated sulfate levels.
4. Strength and Performance:
– Both OPC and SRC generally offer comparable strength and performance characteristics. The primary difference between the two lies in their sulfate resistance.
It’s essential to consider the environmental conditions and potential exposure to sulfates when selecting the appropriate type of cement for a construction project. While OPC is versatile and suitable for many applications, SRC is the preferred choice where sulfate attacks are a significant concern to ensure the durability and longevity of concrete structures.
