Blowup

Blowups occur in hot weather, usually at a transverse crack or joint that is not wide enough to permit expansion of the concrete slabs. The insufficient width is usually caused by inflation of incompressible materials into the joint space. When expansion cannot relieve enough pressure, a localized upward movement of the slab edges (buckling) or shattering will occur in the vicinity of the joint. Blowups can also occur at utility cuts and drainage inlets. This type of distress is almost always repaired immediately because of severe damage potential to aircraft. The main reason blowups are included here is for reference when closed sections are being evaluated for reopening.

Severity Distress Example Description
Low Overview photo of a transverse PCC joint with a low-severity blowup.  A slight difference in height is noticable between the two slabs. Buckling or shattering has not rendered the pavement inoperable, and only a slight amount of roughness exists.
Medium Overview photo of a transverse PCC joint with a medium-severity blowup.  Both slabs show some distress at the joint, but the right slab has considerable spalling due to the blowup. Buckling or shattering has not rendered the pavement inoperable, but a significant amount of roughness exists.
High Overview photo of a transverse PCC joint with a high-severity blowup.  Both slabs have considerable spalling due to the blowup. Buckling or shattering has rendered the pavement inoperable.