How many times should each level be compressed with a rod during a slump test?

During a slump test, each level of concrete should be compressed with a rod precisely 25 times. This specific number of compressions is established to ensure that the test is consistent and that the concrete sample is properly compacted to eliminate air pockets and to achieve an accurate representation of its workability.

The purpose of the slump test is to measure the consistency and flow of fresh concrete. By using the specified amount of rod strokes, the test provides a standardized method to assess how well the concrete will perform in actual construction conditions. Properly following this protocol helps in achieving reliable results, which are critical for quality control in construction projects.

Other quantities, such as 10, 15, or 20 compressions, do not align with industry standards for slump tests, which could lead to incomplete compaction and, therefore, inaccurate measurements of the concrete’s consistency. These standards are set to ensure consistency across different tests and greater reliability in the interpretation of the results.