Florida DOT Concrete Batchman/Operator Practice Exam

When weighing cement in a cumulative weigh hopper, what must be weighed first?

1. Pozzolans

2. Slag

3. Cement

4. Aggregate

The correct answer is: Cement

When weighing cement in a cumulative weigh hopper, cement must be weighed first because it is the primary binding material in concrete. The proper sequence of weighing materials is crucial for achieving uniformity and ensuring that the concrete mix meets the specified design requirements. Weighing cement first helps in establishing a consistent ratio between the cement and the other materials, such as aggregates and any supplementary cementitious materials like pozzolans or slag. The weights of these additional materials are often adjusted based on the weight of cement being used, ensuring that the total concrete mix maintains its intended properties, including strength and workability. By weighing cement first, you also eliminate potential errors that might arise from variations in the properties and moisture contents of the aggregates or other materials, which could adversely affect the overall quality of the concrete. The correct order of weighing ensures that the batching process is standardized and efficient.