ACI Concrete Field Testing Technician - Grade I Practice Exam

Which test provides a quick estimate of workability in freshly mixed concrete?

1. Vebe test

2. Slump test

3. Compression test

4. Tensile test

The correct answer is: Slump test

The slump test is widely recognized as a quick and effective method to estimate the workability of freshly mixed concrete. It involves measuring the vertical settlement of a conical mold filled with concrete. The degree of slump indicates how easily the concrete can be mixed, placed, and finished, which are crucial factors for construction applications. A higher slump value generally signifies a more workable mix that can flow easily into place, while a lower slump indicates a stiffer mix that may be more difficult to work with. This test is particularly favored in the field due to its simplicity and quick results, allowing technicians to assess the consistency and suitability of the concrete for a specific job without the need for extensive equipment or lengthy procedures. While other tests, like the Vebe test, can also assess workability, they are not as commonly used for a quick estimate in everyday field testing. The compression and tensile tests are primarily designed to evaluate the strength of concrete rather than its workability, focusing on different properties altogether. Thus, the slump test stands out as the benchtop technique for determining the workability of freshly mixed concrete efficiently.