570.3 Repair of Buckled Pavement

"Blowups" or buckled pavement occurs when the compressive stress due to high temperatures exceed the strength of the concrete at some locations in the pavement. These blow-ups usually occur on very hot afternoons, as the maximum temperature for the day is reached.

A blow-up generally begins by slight spalling at the joint. The condition may either get progressively worse or the blow-up may occur instantaneously. In most cases, temporary or emergency repairs will be required to accommodate traffic.

Where a concrete pavement slab is raised at a joint, due to a blow-up of buckled pavement and is free of the subgrade, it may be necessary to cut off the end of the slab to permit it to fall back into position. The widening of the expansion joint should be kept as narrow as the use of air chisels and other tools will permit.

If a concrete saw is available, the joint can be widened neatly to relieve the pressure and to prevent future buckling.

If the slab has been shattered during the buckling process temporary repairs will require the removal of shattered and broken concrete, the breaking out of sufficient width of the slab to relieve the pressure and to a allow the slab to reset and temporarily repaired using bituminous materials. Permanent repairs should be made later by removing the bituminous material and replacing with concrete in accordance with instruction outlines under Concrete Replacement.

Measures may be taken when there is evidence of compression in the pavement and blow-ups or buckling may be prevented by removing non-compressible materials that have infiltrated the expansion joint, by cutting away a part of the slab and widening the expansion joint or by providing an additional expansion joint. It is recommended that the pavement receptive to blow-ups be patrolled when "blow-ups" are anticipated to provide for traffic safety.