Final answer:
The slump test measures the workability of fresh concrete with certain time constraints. The entire test should be completed within 5 minutes after acquiring the sample, and the steps from the initial pour to the final measurement should be done promptly to ensure accuracy.
Step-by-step explanation:
The slump test is a concrete consistency test used to measure the workability of fresh concrete before it sets. It has specific time limitations that are important to follow to ensure the accuracy of the test results.
For the entire test, the time limit is typically within 5 minutes after the sample has been obtained, and the concrete should be tested as soon as possible. From the initial pour, when the concrete is placed into the slump cone, the test should be conducted without delay. Once the cone is filled, the concrete should be consolidated then the cone is lifted off, allowing the concrete to slump due to gravity. The change in height of the concrete is then measured immediately.
The reason for these time limitations is twofold: 1. to measure the time it takes for a quantity of liquid to flow through a narrow vertical tube and 2. to measure the time it takes steel balls to fall through a given volume of the liquid. Delays can result in inaccurate measurements as the concrete begins to set.