What does the friction course require before placement?

The requirement for preparing the shoulder before the placement of the friction course is crucial because it ensures proper bonding and alignment of the asphalt layers. When the shoulder is adequately prepared, it guarantees that the transition from the main roadway to the shoulder is smooth and maintains the integrity of the pavement structure. Proper shoulder preparation helps prevent issues such as cracking or premature failure in the asphalt layer. Furthermore, an appropriately groomed shoulder enhances drainage and contributes to the overall performance and lifespan of the pavement.

In contrast, other options, while they may involve important aspects of roadway maintenance or construction, do not specifically relate to the prerequisites for placing the friction course. For instance, cleaning the area of debris and testing for quality are necessary steps in the general paving process, but the primary focus of the friction course placement is the specific preparation of the shoulder to ensure a successful and durable installation.