14 LONGITUDINAL CRACKING Longitudinal cracking in asphalt is a type of pavement distress that occurs when cracks run parallel to the centerline of the pavement. Longitudinal cracking can allow moisture to infiltrate the pavement, making it rougher. Longitudinal cracking is caused by issues related to linear features. It may be related to: • Inadequate compaction between adjacent passes of asphalt construction. • Inability of the pavement section to support loads in the wheel path. • Frost heave in the wheel path resulting from heavy traffic and moist fine‑grained soils within the frost zone. • Inadequate compaction and subsequent settling of utility trenches. • Reflection from underlying layers. • Thermal shrinkage. • Loss of volatile compounds in the binder over time. • Poor joint construction. To prevent longitudinal cracking, you can: • Using true warm mix where the temperature is reduced during application instead of hot mix asphalt. • Maintain a surface treatment on the asphalt to preserve its flexibility. Tips on responding to longitudinal cracking: • Fill cracks soon after they appear to prevent the intrusion of water under the asphalt. • If the cause of longitudinal cracking is related to conditions below the asphalt layer, correction of these conditions will be required for a permanent solution to the problem.
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