Ordinary Portland Cement (OPC)

In the realm of building, ordinary Portland cement, or OPC, is the most often used type of cement. It is the fundamental component used to make non-specialty grouts, mortar, stucco, and concrete. The strength of regular Portland cement is used to grade it. The grade represents the mortar cube’s anticipated compressive strength after 28 days of setting

Grades of Ordinary Portland Cement (OPC)

The following is a discussion of the various OPC grades:

1. Grade: OPC 33 Cement

Under typical environmental conditions, this grade of cement is utilized for general construction. Nevertheless, OPC 33’s use and demand have been affected by its low compressive strength and the availability of stronger grades of cement.
OPC 33’s Compressive Strength ( IS Code for Ordinary Portland Cement, 33 Grade is IS 269: 1989.) When determining the compressive strength, the average compressive strength of three mortar cubes with a face area of 50 square centimeters is taken into consideration. One part cement and three parts regular sand make up these mortar cubes.

2. Grade: OPC 43 Cement

The most often used type of cement in the nation right now is this one. For typical RCC construction when the concrete grade is up to M30, OPC 43 is utilized. It is also utilized in the building of non-structural tasks like flooring and plastering, as well as precast products like pipes and blocks, tiles, and asbestos products.

Compressive Strength of OPC (IS Code: IS 8112: 1989 for 43 Grade Ordinary Portland Cement.)

3. Grade: OPC 53 Cement

When we require more durable concrete with a very low cement percentage, we utilize OPC 53. Using OPC 53 in the concrete mix design allows us to save 8–10% on cement for concrete M20 and up. This cement grade is utilized for specialist projects where the concrete grade is M25 and above, such as prestressed concrete components, precast items like paving blocks, construction blocks, etc., runways, concrete roads, bridges, and other RCC works.

Compressive Strength of OPC (53 IS 12269: 1987 for Ordinary Portland Cement Specification for Grade 53)

Characteristics of OPC Cement Physically

Before authorizing the cement for use, the following physical requirements—aside from the cement’s compressive strength—must be verified:

Fineness

The specific surface area of cement, as determined by Blaine’s air permeability method, must not be less than 225 m2/kg. This is true for all cement grades.

Soundness

The “Le-Chatelier” technique of testing states that unaerated cement cannot expand by more than 10 mm. Unaerated cement cannot expand by more than 0.8 percent when evaluated using the autoclave test. This is true for all cement grades.

Setting Time

The cement’s setting time must meet the following criteria when evaluated using the Vicat equipment method:

(i) 30 minutes should be allotted for the initial setting time

(ii) 600 minutes should be allotted for the final setting time

All cement grades are subject to the aforementioned setting time limitations.

OPC Cement Chemical Requirements

The following are the chemical specifications for OPC 33, OPC 43, and OPC 53:

Referenced

1. IS 269: 1989 for OPC 33 Grade
2. IS 8112: 1989 for OPC 43 Grade
3. IS 12269: 1989 for OPC 53 Grade