pavement work tips - No 9 August 2010

INTRODUCTION Preparation Activities Key Summary Maintenance works need to be planned and Cracking carried out well in advance to ensure that Areas of severe This issue of newly resealed pavements have a surfacing crocodile cracking “pavement work that is: should be removed and tips” provides  waterproof and durable replaced. guidelines for the  uniform in appearance Cracks wider than timing and 2 mm should be correction of  of suitable width repaired by sealing with: pavement defects  of adequate ride quality. prior to resealing  hot or cold pour An initial assessment must be made to crack sealants determine whether defects can be corrected  binder and grit systems with the selection of seal type, for example  overbanding (striping) techniques the use of a SAM seal to correct cracking, or  application of a geostrip. whether pretreatment is required. Cracks less than 2 mm wide, and minor PREPARATION OF A crocodile cracking, can generally be successfully PAVEMENT FOR RESEALING treated with a reseal or SAM seal using polymer modified binder, geotextile reinforced seal or General fibre reinforced seal. The following pavement preparation A further alternative, for particular application, activities should always be carried out in is use of a slurry surfacing to repair shape and advance of resealing: lock in cracked segments, followed by a SAM seal  repair any defects such as wide cracks, for waterproofing. pot holes and structural deficiencies; Crack sealing treatments are further described  repair any shoved, rutted or depressed in Pavement Work Tip No 8 and skin patching areas that will affect the shape and ride quality of the reseal; techniques in Pavement Work Tip No 45.  repair any edge breaks to re-establish the Structural Defects/Pot Holes width of the pavement; Structural defects should be repaired by  avoid other concurrent maintenance patching. The materials used for the repairs activity that may adversely affect the early should be given sufficient time to settle in life of the reseal, such as linemarking, before further treatment. Pot holes should be repairing shoulders, trenching or squared and tack coated prior to filling with reinstating any surface drainage. asphalt. A pavement that is well prepared for Ruts and Depressions resealing should have a uniformly textured surface, a smooth ride where practical, and Where ruts and depressions exceed about contain only minor defects that can be 20 mm in depth, they should be repaired by corrected by the reseal. regulating with an asphalt overlay, slurry surface- ing or granular resheet. The texture of the repaired surface should match the adjoining surface texture as far as Flushing practicable. Any variations in the existing Flushed or "fatty" surfaces should be treated. surface are likely to be reflected into the For possible treatment types, refer to Pavement texture of the new surface. Work Tip No 7. continued on reverse

pavement work tips are produced by AUSTROADS in conjunction with AAPA

For more page 2 information on any of the construction practices discussed OTHER MAINTENANCE Techniques for treatment of flushed seals in "pavement work ACTIVITIES and non-uniform surface texture are further tips'', please contact described in Pavement Work Tip No 7. either your local Regrading to repair shoulders or reinstating AUSTROADS longitudinal surface drainage should be representative or Excessive Crack Sealing: Excessive AAPA: undertaken well in advance of resealing work. binder used in crack sealing and overbanding tel (03) 9853 3595; Similarly, shoulder repairs should not be can reflect through the reseal, causing binder fax (03) 9853 3484; e-mail: undertaken too soon after sealing as the surfacing, pick-up and unsightly appearance. Where which may be tender, is easily damaged. [email protected]. there is extensive cracking, it may be A complete list of PREPLANNING preferable to use binder and grit, or apply a “pavement work To ensure satisfactory performance of the reseal, SAM seal as referred to above. tips” issues is it is necessary to carry out the repairs available on Extent of repairs: It is often not AAPA’s website:  using the appropriate materials economical or practical to return the www.aapa.asn.au  well in advance of the reseal. pavement to an "as new" condition. The Issues may be Advance preparation is essential. Uncured extent of repairs will depend on the type of downloaded using Adobe Acrobat bituminous maintenance treatments and embed- road, but should be sufficient to repair the Reader. Copies may ment of aggregate into patching materials can lead major defects, and waterproof the pavement also be obtained to bleeding and adversely affect the quality of the surface. from AAPA. subsequent reseal. Where preparation works are extensive, it Material may be Table 1 provides desirable guidelines for the pre- freely reproduced may be appropriate to use a polymer providing the planning and undertaking of other maintenance modified binder or geotextile reinforced seal source is treatments. rather than carry out extensive crack sealing. acknowledged. This edition was OTHER FACTORS REFERENCES prepared by Treating Pavements with Non-Uniform Pavement Work Tip No 7, Treatment of members of the Surface Texture: Desirably, large variations in bleeding and flushed surfaces. Bituminous Surfacings surface texture between wheel paths and other Pavement Work Tip No 8, Treatment of Research Reference non-trafficked areas should be corrected to cracks in flexible pavements. Group. provide a more uniform surface texture prior to Pavement Work Tip No 45, Skin Patching. resealing.

Desirable time for Maintenance treatment maintenance activity to be completed before resealing1 Repair of edge breaks, patching and regulating with: • Premixed/cold mix asphalt made with cutback bitumen 6 months • Premixed/cold mixed asphalt made with bitumen emulsion 4 months • Hot mix asphalt 2 months • Slurry surfacing 3 months Patrol reseals using: • Cutback bitumen and grit 6 months • Emulsion and grit 1 months Crack sealing using: • Emulsion 2 months • Cutback products 6 months • Hot bitumen products 2 months Treatment of flushed areas by asphalt patching or using solvents 2 months (refer to Pavement Work Tip No 7) Maintenance of shoulders and longitudinal drains 2 weeks (and 2 weeks after) Linemarking before resealing 3 to 6 months (if required) 1. May vary depending on climatic and trafficking conditions.

Austroads and AAPA believe this publication to be correct at the time of printing and do not accept responsibility for any consequences arising from the use of the information herein. Readers should rely on their own skill and judgement to apply information to particular issues.