Florida DOT Concrete Batchman/Operator Practice Exam

In concrete, what material has a specific gravity of one?

1. Cement

2. Sand

3. Water

4. Gravel

The correct answer is: Water

In concrete, water has a specific gravity of one, which serves as a reference point for measuring specific gravities of other materials. Specific gravity is a dimensionless quantity that indicates how dense a substance is compared to water. Since water’s density is approximately 1 g/cm³, this results in a specific gravity value of one. Understanding that water holds this unique position is crucial, especially when mixing concrete. The specific gravity of other components like cement, sand, and gravel is greater than one. Their higher density impacts the overall weight and properties of the concrete mix. By knowing the specific gravity of each material, concrete batchers can accurately calculate the proportions needed to achieve the desired strength and workability in the final product. This knowledge ensures that the concrete performs as expected under different conditions.