What shape is the mold used for the slump test?

The mold used for the slump test is shaped like a cone. This conical shape is essential for accurately measuring the workability of fresh concrete. During the slump test, fresh concrete is placed into the cone-shaped mold in three layers, each layer being compacted. After the mold is carefully lifted, the amount the concrete slumps or settles downward is measured. The conical design of the mold helps facilitate the flow of the concrete and provides a definitive shape for consistent measurements.

The other shapes, such as a cube or a cylinder, do not allow for this specific type of flow behavior measurement, which is critical for understanding the concrete's consistency. A pyramid shape would also not conform to the requirements of the slump test, as it would not provide a uniform surface area for observing the slump. Thus, the conical shape is both practical and fundamental for this type of test, ensuring accurate workability assessments of the concrete mix.