Which piece of equipment is essential for core sampling?

The essential piece of equipment for core sampling is the concrete saw. Core sampling is a process used to retrieve cylindrical samples of asphalt or concrete from a paved surface, allowing for analysis of the material composition, thickness, and quality. The concrete saw is specifically designed to accurately cut through hard materials, making it ideal for this purpose. Its precision ensures that the core samples are taken without damaging the surrounding pavement, which is crucial for both testing and subsequent repairs.

The other equipment listed does not serve the same function. An asphalt roller is used primarily for compacting asphalt during paving, a road grader is utilized to create a smooth surface by grading and leveling the roadbed, and a pneumatic hammer is typically used for breaking up concrete or asphalt rather than extracting core samples. Thus, the concrete saw is uniquely suited for the task of core sampling, making it the correct choice.