Cement is one of the fundamental materials used in the construction industry. It is used in various forms to build strong and durable structures. They act as binding agents as they are the main materials in concrete, mortar, and other materials. The quality and the cement type play a significant role in strength and long-life determination.
This blog provides you with details regarding different types of grade cements focusing on 43 Grade and 53 Grade Cement.
What is 43 Grade Cement?
OPC (Ordinary Portland Cement) of 43 grade conforms to IS:8112-1989 (an Indian code book specifying standards for OPC) and has a designed strength of 43 MPa after 28 days. While its early strength is lower than 53 Grade cement, it achieves similar strength over time. The initial setting of 43-grade cement is slower, releasing moderate heat during hydration, reducing micro-cracking risk with proper curing.
It’s recommended for general civil construction, RCC works up to M-30 grade of concrete and precast items. OPC of 43 grade is also used in plastering and flooring.
What is 53 Grade Cement?
OPC 53 grade cement was introduced by BIS (Bureau of Indian Standards) in 1987 and commercially produced from 1991. It conforms to IS:12269-1987 with a minimum 28-day strength of 53 MPa. It can be used in high-load structures like bridges and skyscrapers, due to its high strength and durability.
There may be a possibility of micro cracking if the 53-grade cement is not handled properly due to fast hydration. Proper supervision and curing are essential to mitigate the risks. This grade is suitable for applications needing high strength and stringent quality assurance.
Differences Between 43 and 53 Grade Cement
Compressive Strength
43 Grade Cement:
This grade has a minimum compressive strength of around 43MPa after curing for 28 days. They are used in projects where very high strength is not an important requirement.
53 Grade Cement:
This grade has a minimum compressive strength of around 53MPa after curing for 28 days. It can be used in projects that need very high load-bearing capacity and high initial strength.
Fineness
The hydration rate, setting time and strength development are affected by fineness.
43 Grade Cement:
43-grade cement needs 225 square metres per kilogram as minimum fineness.
53 Grade Cement:
53-grade cement needs a high minimum fineness of up to 370 square metres per kilogram. This can help in quick hydration and early development of strength.
IS Codes
43 Grade Cement:
Conforms to IS 8112 standards.
53 Grade Cement:
Conforms to IS 12269 standards.
Strength Development
The strength development of these grades varies at different stages.
43 Grade Cement:
- 3 days: 23 N/mm²
- 7 days: 33 N/mm²
- 28 days: 43 N/mm²
53 Grade Cement:
- 3 days: 27 N/mm²
- 7 days: 37 N/mm²
- 28 days: 53 N/mm²
Strength Gain
43 Grade Cement:
The 43-grade cement starts to get stronger after 28 days. It can be used in projects where long-term strength development is necessary.
53 Grade Cement:
53-grade cement gets its strength within 28 days. It can be used in fast-paced construction projects.
Heat of Hydration
43 Grade Cement:
It releases heat at a moderate level during the hydration process.
53 Grade Cement:
It releases heat at a particularly fast pace. This may cause microcracking if not maintained properly.
Cost
43 Grade Cement:
It is commonly obtained at a lower price of around ₹350 to ₹400 per 50kg bag. Cheaper but requires more quantity for higher grade concrete (above M30), making it less economical for high-strength applications.
53 Grade Cement:
It is expensive compared to 43-grade cement with a price of around ₹400 to ₹500 per 50kg bag. Although more expensive, it can save 8-10% in costs for high-strength concrete due to its higher performance and reduced quantity requirement.
Applications
43 Grade Cement:
43-grade cement can be used for PCC and RCC works up to M30 grade of concrete, tiling, plastering, flooring, masonry, pathways, and finishings of buildings, roads, bridges, culverts, and structures that retain water.
53 Grade Cement:
53-grade cement can be used in RCC structures such as columns, beams, footings, slabs, industrial works, high-rise buildings, and precast concrete items including tiles, pavement, pipes, railways, blocks, and sleepers. Additionally, it can be used in projects that need high early strength.
Chemical Composition
Both grades have similar chemical compositions but differ in specific ratios that affect their performance.
43 Grade Cement:
In 43-grade cement, the lime-to-silica ratio varies from 0.66 to 1.02.
53 Grade Cement:
In 53-grade cement, the lime-to-silica ratio varies from 0.8 to 1.02.
Curing
Curing is a process to which the concrete maintains the temperature and moisture for the cement to ultimately gain strength.
The curing process is the same for both 43 grade cement and 53 grade cement. However, they may have different strengths.
Loss on Ignition
When water comes in contact with the cement it emits a large amount of heat to form solid concrete. The loss of ignition measures the amount of heat generated and water lost to make sure the strength remains unchanged.
43 Grade Cement:
It should not exceed 5% by mass.
53 Grade Cement:
It should not exceed 4% by mass.
Suitability for Different Climates
43 Grade Cement:
It is used mainly in hot climates as it has moderate levels of hydration heat.
53 Grade Cement:
It is used mainly in cold climates as it has a high hydration heat property.
Practical Considerations
43 Grade Cement:
This cement provides flexibility in use for a wide range of construction projects where extreme early strength is not crucial.
53 Grade Cement:
This cement can be used in fast-paced construction and applications that need high strength. It must be handled and cured carefully to avoid microcracking
Choosing the Right Cement
When selecting between 43 Grade and 53 Grade cement, consider the following factors:
- Project Requirements
- Environmental Conditions
- Budget
- Construction Speed
Both 43-grade and 53-grade cements have their unique properties and applications. The choice between 43 and 53-grade cement significantly impacts construction outcomes. 43 grade is cost-effective for standard applications, while 53 grade is best for projects demanding rapid strength and durability. However, it is advisable to consult structural engineers to recommend the right cement required based on specific project needs.
FAQs
For most residential constructions, 43-grade cement is sufficient. However, for high-rise buildings, 53 grade cement may be used for certain structural elements.
53-grade cement is generally more expensive than 43-grade cement.
43-grade cement requires a minimum fineness of 225 square metres per kilogram.
53-grade cement requires a minimum fineness of 370 square metres per kilogram.
53-grade cement is preferred for high-rise buildings due to its higher strength.