What is the primary purpose of concrete slump tests?

The primary purpose of concrete slump tests is to assess the workability of the mix. This test provides a simple and quick way to evaluate the consistency and fluidity of fresh concrete, which directly impacts how easily it can be placed and finished. A higher slump value indicates a more workable concrete mix, suitable for applications requiring easy placement, while a lower slump suggests a stiffer mix that may require more effort to work with.

Workability is crucial for ensuring that the concrete can be compacted effectively and that it fills the forms adequately without segregation of materials. Thus, the slump test serves as a practical method for measuring this important property, allowing construction teams to adjust the mix design to meet specific job requirements.

In contrast, the other options focus on aspects that are not evaluated by the slump test, such as weight, temperature, or curing efficiency. These factors may be important in different contexts, but they do not relate to the immediate assessment of concrete workability, which is the main focus of a slump test.