ORDINARY PORTLAND CEMENT

Ordinary Portland Cement (OPC) is the most widely used type of cement globally, serving as the basic ingredient in concrete, mortar, and many construction applications.

Key Description:

• Composition: Primarily made from calcareous (limestone) and argillaceous (clay/shale) materials, ground and blended, then heated in a kiln at ~1450°C to form clinker. The clinker is finely ground with 3–5% gypsum to control setting time.
• Grades: Available in three main grades (IS 269:2015 – India; similar in ASTM C150 – USA):
  • OPC 33: Minimum 28-day compressive strength = 33 MPa (used for general construction, low-load structures).
  • OPC 43: Minimum 28-day strength = 43 MPa (most common for residential/commercial buildings).
  • OPC 53: Minimum 28-day strength = 53 MPa (high-strength applications like bridges, prestressed concrete).