Repair guide
Asphalt Crack Filling and Frost Heave Repair in Alaska
Last updated
Cracks and frost heaves are the most common pavement problems in Southcentral Alaska. The fix depends on the cause: a surface crack in otherwise healthy asphalt is a cheap, routine repair, while heaving or alligator cracking usually means water and frost are working on the base below.
Why does asphalt crack and heave in Alaska?
Most Alaska pavement damage comes from water and cold working together. Water seeps into cracks or the base, freezes and expands, and in frost-susceptible soils builds ice lenses that lift the pavement. Spring thaw then leaves the base saturated and weak.
Asphalt is also stiffer and more brittle in extreme cold, so it shrinks and can crack in long transverse lines (thermal cracking). Add oxidation from age, studded tires and heavy vehicles, and you get the familiar mix of crack types.
Identify the type of damage first
| What you see | Likely cause | Typical repair |
|---|---|---|
| Single straight cracks across or along the driveway | Thermal shrinkage, aging, reflective cracking from old pavement below | Clean and fill with hot-pour rubberized crack sealant |
| Interconnected cracks in a pattern like alligator skin | Base failure, often saturated or weak base, heavy loads | Cut out and patch full depth, fixing the base and drainage |
| A hump or ridge that appears in winter and partly settles in summer | Frost heave from ice lenses in frost-susceptible soil | Excavate the frost-susceptible soil, replace with free-draining gravel, improve drainage, repave |
| Dips or depressions | Settlement, poor compaction or thawing of buried organics | Remove, rebuild and compact base, then patch |
| Edge breaking and crumbling | Unsupported edges, plow damage, water at the edge | Patch, back the edge with compacted gravel, adjust snow management |
| Potholes | Water through cracks, freeze-thaw, traffic | Cold patch as temporary fix; hot-mix patch when the season allows |
How is crack filling done correctly?
Effective crack filling means cleaning the crack completely, making sure it's dry, and filling it with a flexible sealant that stays bonded as the pavement expands and contracts. Hot-applied rubberized sealants are the common professional choice for working cracks.
- Clean out the crack. Remove vegetation, dirt and loose material with a wire brush, crack-cleaning tool or compressed air. Wider cracks are sometimes routed to create a clean reservoir.
- Dry it. Sealant won't bond to a damp crack. Professionals often use a heat lance for this.
- Backer rod for deep cracks. Deep cracks may get a foam backer rod so sealant isn't wasted and can flex properly.
- Fill and shape. Sealant is applied slightly above or flush with the surface and may be struck off with a squeegee to form a thin band.
Pourable cold-applied fillers from hardware stores work for small DIY repairs on narrow cracks, but they tend to have a shorter life than hot-pour materials on cracks that open and close a lot with temperature.
When is the best time to fill cracks?
Cracks are widest in cool weather, so many contractors prefer filling in spring or fall when the crack is open but the pavement is dry and above the product's minimum temperature. Filling before winter keeps water out during the freeze-thaw season, which is when it does the most damage.
Fixing frost heave: treat the cause
A frost heave needs three things: frost-susceptible soil (typically silts and some fine sands), a supply of water, and freezing temperatures reaching that soil. Remove any one and the heaving stops. Practical fixes, from least to most involved:
- Improve drainage. Redirect downspouts, eliminate low spots, and keep meltwater from snow piles off the driveway. Sometimes this alone reduces seasonal movement.
- Excavate and replace. The durable fix is to dig out the frost-susceptible soil in the problem area to an adequate depth and replace it with compacted, free-draining gravel, then repave.
- Insulation. In some designs, rigid foam insulation board placed under the pavement section reduces frost penetration. This is an engineered detail and needs adequate cover over the board; ask for experience with it before relying on it.
Grinding down a heave or patching over it only treats the symptom; the bump typically comes back the next winter.
Temporary winter repairs
Hot-mix asphalt plants generally don't run through the winter, so winter potholes get cold patch: a workable mix you can tamp in place. It's meant to be temporary. Clear out water and loose debris, overfill slightly, compact with a tamper or tire, and plan a permanent repair for the paving season.
Frequently asked questions
Should I fill driveway cracks before winter?
Yes, if conditions allow. Sealing cracks while the pavement is dry and above the sealant's minimum temperature keeps water out during freeze-thaw season, when cracks grow fastest.
Will a frost heave go away by itself?
A heave usually settles partly when the ground thaws, but as long as frost-susceptible soil, water and freezing temperatures are all present, it tends to return each winter and the pavement cracks more each cycle.
Can I patch a pothole in winter?
You can use cold patch as a temporary repair. Clear water and debris, fill, and compact it firmly. Plan a permanent hot-mix patch during paving season.