What characterizes checking under the roller?

When evaluating the characteristics of checking under the roller, the phenomenon is primarily associated with the formation of small cracks that run parallel to the roller drum during the compaction process. This parallel alignment occurs because the weight and pressure applied by the roller causes strains in the asphalt surface, leading to these types of minor cracks as the material adjusts and compacts.

These small parallel cracks are indicative of proper rolling and compaction techniques, where the asphalt is sufficiently manipulated without excessive segregation or damage to the overall surface integrity. Observing cracks that run parallel supports the understanding that the rolling action effectively applied pressure evenly across the surface, a fundamental aspect of achieving quality in Hot Mix Asphalt construction.

In contrast, larger cracks, regardless of their orientation, typically signify distress in the asphalt due to failing structural integrity or inappropriate rolling techniques. Hence, the identification of small cracks running parallel to the roller drum becomes a key diagnostic element for inspectors assessing the quality of the asphalt layer during the compaction phase.