This question was previously asked in

Gujarat Engineering Service 2017 Official Paper (Engineering Aptitude)

Option 1 : Compression test on 15 cm cubes at 28 days

Gujarat Engineering Service 2019 Official Paper (Civil Part 1)

757

150 Questions
150 Marks
90 Mins

__Explanation:__

- Compressive strength is defined as the strength of the hardened concrete which gives the measure of the concrete’s ability to resist compressive loads.
- It can be found out by testing standard-sized concrete cubes (15 cm x 15 cm x 15 cm) or cylinders (15 cm diameter and 30 cm height) under Compression Testing Machine after 7 and 28 days taking an average of three samples.

__Additional Information__

- Cube compressive strength is approximately 15 % more than the cylinder compressive strength.
- This difference in compressive strength occurs because, in the cylinder, less end restraint and more uniform distribution of stress over the cross-section exist due to which the cylinder strength is probably closer to the true uniaxial compressive strength of concrete than the cube strength.