Ordinary Portland Cement (OPC) is a widely used type of cement in construction. It is made by heating limestone and clay in a kiln, which produces clinker that is then ground into a fine powder. OPC is known for its strength and durability, making it suitable for various applications, including buildings, bridges, and roads. OPC is classified into different grades based on its compressive strength, with Grade 33, Grade 43, and Grade 53 being the most common. It is typically mixed with water, sand, and aggregates to create concrete, which is essential for modern infrastructure development.