By Kevin Shell
Asphalt Specialists, Inc.
Edited article first published in
Michigan Chapter
community
ASSOCIATIONS INSTITUTE

Asphalt Maintenance, Repair & Replacement
Everyone has heard the saying; “There are two seasons in Michigan – winter and road construction.”  Early spring is the start of the second season.  The best time for asphalt repair is during warm weather in spring, summer, & fall. 

THE FOLLOWING IS ABOUT ASPHALT PAVING, SEALING, REPAIR & REPLACING.  THIS IS A VERY BROAD TOPIC WITH A LOT OF INFORMATION.  IT IS PRIMARILY TAILORED FOR CONDOMINIUM ASSOCIATIONS AND MANAGERS.

In assessing the pavement condition for repair or reconstruction during the summer, the first step is to visually inspect the asphalt in early spring after the ground has thawed.
Items to note are cracks, “alligatored asphalt”, deterioration around catch basins, and of course, those pesky potholes.  Hopefully, maintenance repair has been performed prior to pothole formation.
If your inspection leaves you unsure of the next step, the services of an engineer or meeting with a reputable contractor to review your pavement condition is advisable.  Either can assist you in drafting the specifications for repair or reconstruction.
MAJOR PROJECTS SHOULD HAVE AN ENGINEER INVOLVED EARLY ON TO DETERMINE THE BEST COURSE OF ACTION.  CORE SAMPLES & ANALYSIS OTHER THAN VISUAL INSPECTION MAY BE NEEDED TO DETERMINE HOW BEST TO PROCEED.  HIRING AN ENGINEER MAY SEEM EXPENSIVE, BUT THEIR COST IS TYPICALLY ONLY 3% TO 5% OF THE EXPENSE INVOLVED IN MAJOR RECONSTRUCTION.  EMPLOYING AN ENGINEER OFFERS A MEASURE OF PROTECTION TO BOARD MEMBERS AND PROPERTY MANAGERS IN PREVENTING COSTLY ERRORS IN EXECUTING LARGE PROJECTS.
If you are fairly certain of what is needed, another idea is to have a pre bid conference with several reputable contractors.  Indicate the problems, seek their input, and create the needed specifications.  Having written specifications is advisable prior to the bidding process.  Written specs should include a start and completion date, phasing schedule, and any special work rules of your community or association.
If the specifications and scope of work are not clear cut and in writing, you may receive wildly different bids.

If good pavement conditions exist, remember that preventative maintenance can considerably extend pavement life – these measures may include hot rubberized crack filling and sealcoating where applicable.

Whatever type of repairs are needed, it is advisable to schedule the work for late spring, summer, or early fall.  All asphalt products – paving material, rubber joint sealant, sealcoat, etc. are best applied in warm dry weather.  Cold weather is not beneficial to the application of most asphalt paving products.  Cold weather asphalt paving is risky and not always as aesthetically pleasing and should be avoided unless absolutely necessary.

Before we get to the various repair / replacement options, let’s talk for a minute about what causes pavement to fail.

An asphalt roadway or parking lot is actually part of a system.  The system must take into account:  use (heavy or light), ground (subgrade) conditions, drainage – either inverted crown (center drainage), or standard crown (drainage to the curb), and placement of edge drain and catch basins.  Once these factors are accounted for, a cross section for aggregate and asphalt can be determined.  A typical cross section includes a specified depth of aggregate base and a depth of pavement.  In some cases deep strength pavement (no aggregate and 7.5” to 10” of asphalt) may be called for on top of the subgrade, but most often an aggregate base is used prior to placing asphalt.  One typical cross section would be 8” of 21AA stone topped with 4” of asphalt.  There are a variety of different cross sections.

What causes asphalt to fail:

1. Heavier than anticipated loads (garbage trucks, through traffic, etc.).
2. POOR SUBGRADE CONDITIONS (organic material, topsoil, wood, wet clay, poor or no drainage).
3. Excessive water in the subgrade (sprinkling too much, signs that water is coming out of the ground and/or asphalt).
4. Freeze Thaw Cycle (expansion & contraction proportional to the water content with poor subgrade conditions).
5. Overall wear & age (aging of asphalt – flexible when new, brittle when old – from black to grey in color).

Typical Asphalt Maintenance / Reconstruction Terms

1. Cold Patch – asphalt material used to fill potholes (can be used in cold weather) – not a long term repair – very flexible without the strength & durability of Hot Mix Asphalt.  Cold patch is temporary.
2. Hot Rubber Joint Sealing – also Crack Filling – process of filling cracks in asphalt or concrete with flexible rubber material.
3. Sealcoating – process of covering asphalt with a very thin layer of liquid asphalt or liquid coal tar pitch emulsion.
4. Skin Patching – placing a thin layer of 1” to 1.5” of asphalt over the surface of a problem area (reflective cracks will occur).
5. R & R – removal and replacement of deteriorated asphalt.
6. Catch Basin – a surface water collector.
7. Overlay or Capping – placing a predetermined thickness of asphalt over existing asphalt – typically a minimum 1.5” in depth due to aggregate content size (reflective cracks will occur).
8. Butt Joint – when asphalt needs to be removed at a fixed point such as a garage door, or the transition of other fixed points such as existing asphalt, sidewalks, concrete curb, etc. to provide a smooth transition, and more importantly proper drainage.
9. Pulverization – process whereby the entire thickness of existing asphalt is ground into small pieces by machine and then graded & compacted for use as additional base for new asphalt.
10. Milling – grinding and removal of a predetermined depth of asphalt.
11. Aggregate Road Base – typically limestone, crushed concrete or road gravel – standard Michigan designations:  MDOT 21AA (in either crushed concrete or limestone) and 22A road gravel.
12. Undercut – process of removing bad or unstable aggregate base and/or sub-base & replacing with stable aggregate base.  Frequently, larger aggregate known as 1” x 3” or 2” x 4” is used to fill an undercut.  These large aggregates are then “choked off” with 21AA (a much smaller aggregate).
13. Edge Drain – perforated & flexible drain installation used to take sub surface water away from the road or parking area base – important in areas of heavy irrigation and or wet clay soils.
14. Tack Coat – the “glue” used to bond two or more layers of asphalt pavement together – application of tack coat is necessary when placing an overlay over existing asphalt or multi course construction of new asphalt pavement.
15. Geo Grid or Grade Stabilization Fabric – material used to stop wet or unstable sub soils from contaminating (pushing up through) a new aggregate base.
16. Various Grades / types of asphalt – Base Course: 500C, 700C, 11A, - Leveling, Commercial Grade: 1100L, 1300L – Wearing Course, Commercial Grade: 1100T, 36A, 1300T.  There are many other possible grades of asphalt.  Asphalt is made up of only three items: Asphaltic Cement, Aggregates (various sizes), and Air Voids.
17. Compaction – is the key to a successful asphalt system.  To achieve proper compaction requires the correct size of rollers and the subgrade and aggregate base must be intact and hard.  Soft subgrade will transfer up to the surface and cause failures.  In smaller areas where a roller cannot be used for compaction, then a hand tamper is used.  Areas where compaction by hand is necessary are typically “rougher” looking than areas placed and compacted by machines.
18. Grade – a minimum of 1% slope to achieve proper drainage.
19. Asphalt Curb – is placed by a curbing machine and is typically 7” tall by 5” to 6” wide.  This type of curb does not stand up well to snow plows and can be damaged easily by vehicles.  Where possible, asphalt curb should be backfilled with topsoil to add stability to be less likely to be moved or damaged.

20. Concrete Curb & Gutter – is available in various thickness, sizes, and formations – it is much more durable and resistant to damage from snowplows, vehicles, etc. – it is also much more expensive than asphalt curb.  Concrete curb requires backfilling.