The most commonly used cement for producing concrete, mortar, stucco, and non-specialty grouts worldwide is Ordinary Portland Cement (OPC). This type of cement is classified into three grades based on its strength after 28 days of setting, namely 33, 43, and 53 grade. These grades indicate the compressive strength of the cement.
Different countries have their own standards for OPC classification. In India, OPC is classified based on the Bureau of Indian Standards (BIS) and is denoted as OPC-33, OPC-43, and OPC-53. The American Standards classify OPC as Type I, Type II, Type III, Type IV, and Type V, based on its chemical and physical properties. In Europe, OPC is classified according to the EN-197 standard and is denoted as CEM I, CEM II, CEM III, CEM IV, and CEM V, depending on the clinker content and the presence of other materials.
Despite the differences in classification, the basic properties and uses of OPC remain the same across different standards. OPC is widely used in construction because of its high compressive strength and durability.
As per Indian Standards
| Indian Standard Codes | |||||||||
| Grade | 33 Grade | 43 Grade | 53 Grade | ||||||
| Properties | |||||||||
| Chemical Properties | |||||||||
| Ratio of percentage of lime to percentages of silica, alumina and iron oxide | Not greater than 1.02 and not less than 0.66 | Not greater than 1.02 and not less than 0.66 | Not greater than 1.02 and not less than 0.8 | ||||||
| Ratio of percentage of alumina to percentage of iron oxide | Not less than 0.66 | Not less than 0.66 | Not less than 0.66 | ||||||
| Insoluble residue, percent by mass | Not more than 4 | Not more than 2 | Not more than 2 | ||||||
| Magnesia, percent by mass | Not more than 6 | Not more than 6 | Not more than 6 | ||||||
| Total Sulphur content calculated as Sulphuric anhydride (SO2), percent by mass | |||||||||
| (a) When tricalcium aluminate is less than or equal to 5 | Not more than 2.5 | Not more than 2.5 | Not more than 2.5 | ||||||
| (b) When tricalcium aluminate is greater than 5 | Not more than 3 | Not more than 3 | Not more than 3 | ||||||
| Total loss on ignition, percent by mass, Max | Not more than 5 % | Not more than 5 % | Not more than 5 % | ||||||
| Chloride content, percent by mass, Max | Not more than 0.1 % | Not more than 0.1 % | Not more than 0.1 % | ||||||
| Alkali content | Not more than 0.05 | Not more than 0.05 | Not more than 0.05 | ||||||
| Physical Properties | |||||||||
| Setting Time | 3 days | 7 Days | 28 Days | 3 days | 7 Days | 28 Days | 3 days | 7 Days | 28 Days |
| Avg. Compressive Strength in N/mm^2 | 16 | 22 | 33 | 23 | 33 | 43 | 27 | 37 | 53 |
| Fineness in m^2 /kg, Min. | 225 | 225 | 225 | ||||||
| Soundness | |||||||||
| a) By Le Chatelier method, mm, Max | 10 | 10 | 10 | ||||||
| b) By autoclave test method, percent, Max | 0.8 | 0.8 | 0.8 | ||||||
| Setting time | |||||||||
| a) Initial in minutes, Min | 30 | 30 | 30 | ||||||
| b) Final in minutes, Max | 600 | 600 | 600 | ||||||
| Other Information | |||||||||
| Code Reference | IS Code – IS 269 : 1989 | IS Code – IS 8112: 1989 | IS Code – IS 12269 : 1987 | ||||||
As per American Standards
| American Standard – ASTM C 150 | ||||||||
| Types | Type I | Type I A | Type II | Type II A | Type III | Type III A | Type IV | Type V |
| Properties | ||||||||
| Air Content of Mortar | ||||||||
| a) All cements | 12% | 12% | 12% | 12% | 12% | 12% | 12% | 12% |
| b) Air-Entraining Cement | 16% – 22% | 16% – 22% | 16% – 22% | 16% – 22% | 16% – 22% | 16% – 22% | 16% – 22% | 16% – 22% |
| Fineness | ||||||||
| a) Turbidimeter test in m²/kg | 160 | 160 | 160 – 240 | 160 – 240 | – | – | 160 – 240 | 160 |
| b) Air Permeability | 280 | 280 | 280-420 | 280-420 | – | – | 280-420 | 280 |
| Soundness | 0.80% | 0.80% | 0.80% | 0.80% | 0.80% | 0.80% | 0.80% | 0.80% |
| Setting Time in min | ||||||||
| Initial Time | Not less than 45 | Not less than 45 | Not less than 45 | Not less than 45 | Not less than 45 | Not less than 45 | Not less than 45 | Not less than 45 |
| Final Time | Not more than 375 | Not more than 375 | Not more than 375 | Not more than 375 | Not more than 375 | Not more than 375 | Not more than 375 | Not more than 375 |
| Compressive Strength in Mpa | ||||||||
| 1 Day | – | – | – | – | 12 | 10 | – | – |
| 3 Day | 12 | 10 | 10 | 8 | 24 | 19 | – | 8 |
| 7 Day | 19 | 16 | 17 | 14 | – | – | 7 | 15 |
| 28 Day | – | – | – | – | – | – | 17 | 21 |
As per European Standards
| European Standard – EN-197-1 | |||
| Types | Class 32.5 | Class 42.5 | Class 52.5 |
| Properties | |||
| Compressive Strength in MPa | |||
| 2 Days | 10 | 20 | 20 -30 |
| 7 Days | Greater than 16 | ||
| 28 Days | 32.5 -52.5 | 42.5 – 62.5 | Greater than 52.5 |
| Initial Setting Time | Greater than 75 | Greater than 60 | Greater than 45 |
| Soundness | 10mm | 10mm | 10mm |
Uses of Different Type of Ordinary Portland Cement
As per Indian Codes
1. 33 Grade Cement
OPC 33 is a type of cement commonly used for general construction in normal environmental conditions. However, due to its low compressive strength and the availability of higher grades of cement, its use and demand have been impacted.
Despite being a common choice for general construction, OPC 33 has some drawbacks. Its compressive strength is lower compared to other types of cement, which can make it less suitable for certain projects that require higher strength. Moreover, with the availability of higher grades of cement in the market, contractors and builders may opt for stronger options to ensure the durability and longevity of their constructions.
As a result, the demand for OPC 33 has decreased over time. Nonetheless, it remains a viable option for projects that do not require high strength or when cost is a determining factor. Additionally, it is important to consider the environmental impact of cement production, as OPC 33 is often seen as a more sustainable option compared to other types of cement due to its lower clinker content.
2. 43 Grade Cement
OPC 43 is a type of cement that finds its application in various construction projects. It is particularly suitable for the general RCC construction where the concrete grade does not exceed M30. This type of cement is also preferred for making precast items like blocks, tiles, asbestos sheets, and pipes. Additionally, it is also used for non-structural works such as plastering and flooring. Overall, OPC 43 is a versatile and widely used cement type in the construction industry.
3. 53 Grade Cement
OPC 53 is a type of cement that is specifically designed to create higher strength concrete while using a more economical amount of cement. This particular grade of cement is ideal for specialized construction projects such as prestressed concrete components, precast items like paving blocks and building blocks, as well as for the construction of runways, concrete roads, bridges, and other reinforced concrete structures where a minimum concrete grade of M25 is required.
As per American Standards
| Type I | For use when the special properties specified for any other type are not required. |
| Type IA | Air-entraining cement for the same uses as Type I, where air-entrainment is desired. |
| Type II | For general use, more especially when moderate sulfate resistance or moderate heat of hydration is desired. |
| Type IIA | Air-entraining cement for the same uses as Type II, where air-entrainment is desired. |
| Type III | For use when high early strength is desired. |
| Type IIIA | Air-entraining cement for the same use as Type III, where air-entrainment is desired. |
| Type IV | For use when a low heat of hydration is desired. |
| Type V | For use when high sulfate resistance is desired. |