Surface deformation in rigid pavements

Surface deformation is another very common type of distress of jointed rigid pavements. Surface deformation is the difference in elevation across a joint or a crack resulting from vertical movements. 

Vertical movement may develop either by permanent movement in the form of settlement (also known as faulting) or by dynamic movement caused by passing traffic usually associated with mud pumping. Evaluation of faulting may be carried out by using AASHTO R 36 (2013). 

Settlement or faulting is caused by compaction/consolidation or shrinkage of the layers underlying the slab, movements in the underlying ground or lack of effective load transfer between slabs at joints (effectiveness of dowels and tie bars). 

Dynamic movement is caused by lack of support from the sub-base, lack of effective load transfer at joints or poor pavement (surface) or subgrade drainage. 

Severe settlement is treated either by reconstruction of the slab(s) or by the construction of an asphalt overlay after applying a levelling course. 

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