What is defined as a roller pass in pavement construction?

In pavement construction, a roller pass refers specifically to the action of the roller as it moves over the pavement surface. When describing it as one trip of the roller in one direction, it highlights the process whereby the roller compacts the material during its forward travel. This single pass is essential for ensuring that the layers of pavement achieve the necessary density and stability.

Other options, while they may reflect actions taken with rollers, do not accurately capture the definition of a roller pass. For example, the concept of two trips of the roller implies additional movement that is outside the scope of defining a single pass. Similarly, a trip in both directions suggests a more comprehensive action than what is classified as a single pass, and full coverage, while related to the overall compaction effort, does not reflect the straightforward definition of a roller pass.

Therefore, defining a roller pass as one trip in one direction encapsulates the essential action taken during pavement compaction, focusing solely on that forward movement which is crucial for achieving the required pavement characteristics.