Ratio of strength of cement concrete at 3 months to that at 28 days of curing:

The approximate ratio of strength of cement concrete at 3 months to that at 28 days of curing is around 1.2 to 1.5. This means that the strength of concrete continues to increase after 28 days of curing, but at a slower rate.

Explanation:

Concrete strength is directly related to its curing time. The longer it is allowed to cure, the more durable and stronger it becomes. The curing process begins immediately after the concrete is poured, and it continues for several weeks, even months.

During the first few days, the concrete gains strength quickly, and after 28 days, it reaches about 90% of its final strength. However, the curing process continues, and the strength of the concrete increases slowly over the next several months.

The rate of strength gain after 28 days varies depending on several factors, such as the type of cement used, the water-cement ratio, the curing conditions, and the presence of any additives or pozzolanic materials.

In general, the strength of concrete at 3 months is about 20-50% higher than that at 28 days. The exact ratio depends on the factors mentioned above and can vary from project to project.

Conclusion:

In conclusion, the approximate ratio of strength of cement concrete at 3 months to that at 28 days of curing is around 1.2 to 1.5. The strength of concrete continues to increase after 28 days, but at a slower rate, and the exact ratio depends on various factors.

1.15