Trade Topics
January 2004
Paving Repair and Replacement
Stages of Asphalt Deterioration
When estimating asphalt repair or replacement one should be aware of four recognizable states of deterioration that occur on paved surfaces. Some parts of a parking lot will likely be degraded to a greater extent than others and a typical un-maintained lot will show evidence of all four stages:
Stage I Pre-oxidation: The condition of a new parking lot before sunlight, rain and traffic started to wear off the asphalt emulsion topping. Solution: Preventative maintenance every 3-4 years by seal coating and re-striping
Stage II Oxidation - Moderate: Asphalt emulsion has worn away exposing the top surface of aggregate rock beneath Solution: Seal coat using a sand and latex asphaltic emulsion, res-tripe lot.
Stage III Oxidation - Severe: Voids between the aggregate rock have enlarged to a point where the they cannot be satisfactorily bridged with a sealer. Solution: Overlay asphalt with 1&1/2” asphalt topping, re-stripe lot.
Stage IV Alligator Cracking: This condition most frequently appears in the high traffic areas of the lot where cracks form due, in most cases, to unstable base material below the asphalt exacerbated by heavy vehicle traffic. The cracks become connected to each other rendering the look of an alligator hide. This condition may spread rapidly once water has begun to seep through the cracks, liquefying the underlying base material and causing further subsidence and more cracking. Solution: Cut out the areas that are cracking and replace them with new asphalt, seal coat, stripe if necessary. Frequently, in high traffic areas, it is best to increase the thickness of the asphalt from 4” to between 6” to 8”.
The prices given below were solicited from a well known paving contractor. These are rule of thumb costs - several factors will influence the final figures for a specific project, they are:
- Configuration and frequency of landscape islands
- Distance from asphalt plant to the site
- Space availability on the site for for crew and equipment
- The number of phases for the work.
| |
|
UNIT |
Under 10Ksf |
10 - 50 Ksf |
Over 50 Ksf |
1 |
Seal coat (prevents deterioration) |
S.F. |
$0.25 |
$0.20 |
$0.15 |
2 |
Seal coat with sand and latex ( bridges small voids in suface) |
S.F. |
$0.35 |
$0.25 |
$0.20 |
3 |
Asphalt overlay (1-1/2") ( rougher surfaces) |
S.F. |
$1.65 |
$1.50 |
$1.25 |
4 |
Cut and replace to 4" depth (normal traffic areas) where alligatored |
S.F. |
$4.55 |
$3.50 * |
$3.00 * |
5 |
Cut and replace to 6" -8" (heavy traffic areas) where alligatored |
S.F. |
$6.25 |
$4.00 * |
$3.75 * |
6 |
Stripe parking areas - after any of the above |
EACH |
$4.50 |
$4.50 |
$4.00 |
|
NOTE: Costs for items 4 and 5, above, are based upon machine work and
will increase if site conditions dictate hand work.
Isolated cracks can be repaired using the follow methods
| Cracks less than 1/4" wide |
"Cold Pour" crack fill |
L.F. |
$0.25 |
| Cracks between 1/4" and 1" |
Hot rubberized filler |
L.F. |
$0.75 |
| Cracks over 1 " |
Sheet asphalt |
L.F. |
$1.00 |
| Landscape curb replacement |
Minimum 50 L.F. |
L.F. |
$15.00 |
|
Trade Contributor: Granite Construction, San Jose Ca
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