34. Preventative Maintenance Techniques Flashcards
Benefits of preventative maintenance treatments
Slow future deterioration, maintain or improve functional condition, preserve pavement system, and extend life
Crack filling
Lower level operation with lower quality sealant and little preparation
Only on non-working cracks (<2 mm)
Lasts 1-2 years
How much money is saved when $1 is spent on preservation?
$11
Crack sealing
Higher level operation with higher quality sealant and more preparation
Working cracks
Lasts 3-5 years
Fog seals
Light application of diluted slow-setting asphalt emulsion without aggregate cover
Seal pavement, inhibit raveling, enrich asphalt, provide delineation with shoulder
Thickness: < 3 mm
Slurry seals
Mixture of well-graded fine aggregate, mineral filler, and slow-setting asphalt emulsion
Stop raveling and loss of matrix, reduce potential stripping, improve friction
Thickness: 3-12 mm
Microsurfacing
Mixture of polymer based emulsion binder and high quality aggregates
Improve friction, fill surface irregularities, seal pavement surface
Thickness: 10-20 mm
Chip seals
Application of asphalt and aggregate chips rolled into pavement
Seal pavement, improve friction, wearing course
CIR
Cold in-place recycling
Portion of existing AC pavement milled and reclaimed, then mixed and placed back on pavement
HIR
Hot in-place recycling
Upper 25-50 mm of pavement is heated, mixed with recycling agent, and re-laid on pavement
Heater-Scarifier
Surface of pavement is heated, scarified with a set of scarifying teeth, mixed with recycling agent, then leveled and compacted
Patching
Patching existing pavement with bituminous material
Extends service life, used prior to construction of an HMA overlay
Which gradation is most common?
Dense graded
