What are the common materials a road grader is used to spread?

A road grader is primarily designed for grading and leveling surfaces, making it particularly useful for materials that require precise handling to achieve the desired grade and smoothness. The correct answer highlights gravel, dirt, and asphalt as common materials processed by a road grader.

Gravel is often used for road bases and surfaces, and a grader can effectively spread and level it to create a smooth road. Dirt is another common material for constructing unpaved roads, where graders help in achieving the proper elevation and drainage. Asphalt is also a key material in road construction, and while it may require additional machinery for laying down, a grader can be used afterwards to ensure it is properly graded and smoothed out.

The other options include materials that are either not typically associated with road grading or not commonly used in the same context. For instance, concrete and bricks are more often related to construction activities requiring different equipment for precise placement, while materials like mulch and crushed stone may not require the same level of grading but rather spreading, which can be done by other machines or manual labor.