Test for 28-Day Crushing Strength of Cement

The crushing strength of cement is tested to determine its ability to withstand compressive loads and is an important factor in the quality of concrete structures. The test is conducted on mortar cubes made with a specific cement to sand proportion and the strength is measured after 28 days of curing.

Size of the Cubes

The size of the cubes used for testing is 70.7 mm, which is a standard size for this test.

Cement to Sand Proportion

The proportion of cement to sand used in the mortar cubes is an important factor in the strength of the cement. The options given in the question are:

a) 1 : 3
b) 1 : 4
c) 1 : 5
d) 1 : 6

The correct answer is option 'A', which means the cement to sand proportion used in the mortar cubes is 1 : 3.

Explanation

The higher the proportion of cement in the mortar, the higher the strength of the cement. In option 'A', the proportion is 1 : 3, which means that for every 1 part of cement, 3 parts of sand are used. This results in a higher concentration of cement in the mortar, resulting in a higher crushing strength.

On the other hand, if the proportion of cement is lower, as in options 'B', 'C', and 'D', the strength of the cement will be lower. This is because there is less cement in the mortar, resulting in weaker bonds between the particles.

Conclusion

In conclusion, the crushing strength of cement is an important factor in the quality of concrete structures. The test is conducted on mortar cubes made with a specific cement to sand proportion, and the strength is measured after 28 days of curing. The correct answer in this case is option 'A', which means that the proportion of cement to sand used in the mortar cubes is 1 : 3.

It is for strength of CEMENT, not for Concrete.

it is standard things(like size of cube) which is defined by IS code.

C:S = 1:3.

thanks