43 and 53 cement grades show the highest strength attained after 28 days. These are the two Ordinary Portland Cement grades that are most commonly used.

The differences between them are as follows:

• After 28 days, grade 53 cement attains a strength of 530kg/sq cm, while grade 43 cement attains a strength of 430kg/sq cm.
• Grade 53 cement is used in high-speed construction projects such as bridges, roadways, multistory structures, and cold weather concrete. The most commonly used general purpose cement is grade 43 cement.
• Grade 53 cement has a quick setting time and develops strength rapidly. After 28 days, the strength does not significantly rise. Although it starts off with low initial strength, grade 43 cement eventually develops good strength.
• While grade 43 cement produces relatively little hydration heat, grade 53 cement sets quickly and releases a significant amount. As a result, grade 53 Cement may have micro cracks that are not evident on the surface, and adequate curing should be done.
• Grade 53 cement is slightly more expensive than grade 43.