POTHOLES: - CSIR

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Figure 24: Moisture/traffic-associated cracking in the outer wheel track leading to potholing and extensive patching22Figure 25: Potholes resulting from construction deficiencies
Potholes that develop along the centre-line of theroad are frequently the result of poor sealing/bonding of joins between successive runsduring the sealing process. Water can enterthe pavement along these joins, weakeningthe material and forming potholes. Otherconstruction deficiencies (e.g. localised areasof poor compaction because they are too wetduring construction, material segregation, lackof bond between base and seal, etc.) canalso lead to potholes not directly relating to theseasonal moisture movements (Figure 25). Thewidth of the road and whether the shoulders aresealed can also affect the location of potholes.On narrower roads, the inner wheel paths inthe two directions may overlap, resulting in aneffective doubling of the load in this area andpossible development of potholes.Potholes between the centre-line and the outerwheel track, in the zone of moisture equilibrium,are generally the result of unsealed cracks, poorbonding between the base and seal, or localisedareas of poor construction or material quality.2.8 Non-labour-based repairThe majority of pothole repairs will normallybe undertaken using teams of road workers,usually with a mechanical compactor. However,when potholing becomes extensive or affectslong, linear sections of road (Figure 26), it maybe more effective to use a small recycler ormilling machine to remove the affected areaand replace the material with an appropriaterepair material. This process is not discussed inthis document and should follow conventionalrecycling or large repair procedures.Figure 26: Long, linear development of potholes, resulting from inappropriate layer materials23
Page 1 and 2: POTHOLES:Technical guide to their c
Page 3 and 4: forewordWe have great pleasure in p
Page 5 and 6: TABLE OF FIGURESFigure 1:Localised
Page 8 and 9: CHAPTER 2CAUSES OF POTHOLESAlthough
Page 10 and 11: Figure 3: Cracking of asphalt resul
Page 12 and 13: Figure 6: Initiation of potholes as
Page 14 and 15: Figure 8: A typical pothole formed
Page 16 and 17: 14Figure 12: Fatigue cracking of a
Page 18 and 19: 16Figure 14: A typical pothole form
Page 20 and 21: Figure 19: Failure of a patch withi
Page 22 and 23: 2.6 Mechanisms of pothole developme
Page 26 and 27: CHAPTER 3CLASSIFICATION ANDMANAGEME
Page 28 and 29: 3.2 ManagementFor effective managem
Page 30: 4.3 Preliminary treatmentThe area t
Page 34 and 35: of compaction after placement). To
Page 36 and 37: MethodOnce the area to be patched h
Page 38 and 39: 4.5.5 Medium-depth repair (thin bit
Page 41 and 42: CHAPTER 5QUALITY CONTROL5.1 General
Page 43 and 44: 5.2.3 HMA compaction temperatures m
Page 46 and 47: APPENDIX A - Standard form for the
Page 48 and 49: APPENDIX BKey to THE identification
Page 50 and 51: Notes
Page 52: www.csir.co.zaSee www.csir.co.za/po

POTHOLES: - CSIR

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