Florida DOT Concrete Batchman/Operator Practice Exam

When using Calcium Nitrite, what aspect of the concrete mix must be adjusted?

1. Aggregate size

2. Cement content

3. Batch water

4. Admixture quantity

The correct answer is: Batch water

When using Calcium Nitrite in a concrete mix, it is essential to adjust the batch water component. Calcium Nitrite acts as a corrosion inhibitor, and its inclusion into the concrete mixture can affect the overall water-to-cement ratio. This is critical to ensure that the desired workability and strength of the concrete are maintained. Adding an admixture like Calcium Nitrite can inadvertently change the water content needed for the mix to achieve optimal performance, so adjusting the batch water helps to balance the consistency and quality of the concrete. In practice, if the batch water is not adjusted properly when incorporating Calcium Nitrite, it can lead to a mix that is too wet or too dry, which may compromise the final strength and durability of the concrete. Therefore, careful calculations regarding the total water content, including the water from the admixture itself, are necessary to maintain the intended properties of the concrete.