Florida DOT Concrete Batchman/Operator Practice Exam

Can engineers approve sizes #8 and #89 for use in coarse aggregates?

1. No, only standard sizes are approved

2. Yes, either alone or blended with other sizes

3. Only if they are larger than #78

4. Yes, but only for temporary use

The correct answer is: Yes, either alone or blended with other sizes

The response indicating that engineers can approve sizes #8 and #89 for use in coarse aggregates is based on the flexibility in aggregate selection for specific applications within concrete production. These sizes can indeed be used, whether on their own or blended with other aggregate sizes, because they meet certain performance criteria defined in engineering practices. In concrete mixing, the goal is often to achieve a specific density, workability, and strength. By allowing the inclusion of finer aggregates like #8 and the even finer #89, engineers can optimize the mixture's properties, as different sizes can facilitate better packing and distribution of the aggregate within the concrete matrix. This adaptability is essential for achieving the desired characteristics in various concrete applications. Furthermore, standard practices in the industry provide leeway for incorporating non-standard sizes when they meet the specifications and performance needs of a project. Often, the effective design of concrete mixtures can enhance the overall durability and strength of the final product, making the approval for these sizes a strategic decision rather than merely adhering to strict sizing conventions.