A symptom is not a complete diagnosis. The same crack can come from more than one mechanism, and the visible boundary of damage may be smaller than the affected area below it. Record what you see before choosing a treatment.
First: document the pattern
Take overview and close-up photos, add a ruler or familiar object for scale, and mark the date. Then record:
- exact location and approximate dimensions;
- whether the area carries, turns, or parks heavy vehicles;
- whether water appears during rain or snowmelt;
- nearby drains, downspouts, curbs, utility cuts, trees, or retaining walls;
- vertical movement, loose material, pumping, or hollow sound;
- whether the condition is isolated or repeats; and
- how quickly it has changed.
This small record makes a repair conversation far more useful than “there is a crack near the garage.”
Asphalt symptoms
A single longitudinal or transverse crack
What it can suggest: temperature movement, a paving joint, reflection from below, settlement, or the beginning of localized support movement.
What to check: width, branching, vertical offset, water entry, and whether the crack returns after prior sealing.
Next step: protect the opening from water when an appropriate crack treatment is still feasible, but investigate movement or repeated reflection before expecting a seal to be permanent.
Alligator or fatigue cracking
What it looks like: an interconnected network of small polygons, often in wheel paths or repeatedly loaded areas.
What it can suggest: structural fatigue involving the asphalt, base, or subgrade—not merely an aged surface.
Next step: determine the affected depth and extent. A coating does not restore lost structural support. Local full-depth repair or broader reconstruction may be required.
A pothole
What it can suggest: the end stage of cracking, raveling, joint failure, weak support, and water-related deterioration.
Next step: make the area safe, then plan a repair that removes failed material back to firm support. The Asphalt Institute repair guide notes that drainage may also need correction when water contributes to failure.
Raveling or loose stone
What it looks like: progressive loss of aggregate and a rough, open texture.
What it can suggest: age and oxidation, segregation, poor density, an unsuitable mix, fuel or chemical exposure, or construction damage.
Next step: establish depth and extent. A thin surface treatment cannot replace material that is already structurally disintegrating.
Rutting or shoving
What it looks like: wheel-path depressions, ripples, or pushed-up material near stops and turns.
What it can suggest: movement within the asphalt mix, inadequate density, weak layers below, heavy loading, or a combination.
Next step: check whether the displaced depth is limited to the surface or continues through the pavement structure. Match repair depth to the failed layer.
A depression or settled patch
What it can suggest: poorly compacted trench backfill, localized subgrade settlement, drainage failure, or ongoing utility movement.
Next step: use a straightedge and observe it during rain. Correct the cause and elevations before simply filling the low spot.
Bleeding or a shiny, sticky surface
What it can suggest: excess binder or low air voids, especially in heat and under traffic.
Next step: treat loss of skid resistance as a safety concern and obtain a material-specific assessment. Adding sealer can make the condition worse.
Concrete symptoms
A narrow crack through a slab or panel
What it can suggest: drying shrinkage, restrained movement, delayed or ineffective jointing, thermal change, load, or support movement.
What to check: whether the crack is stable, widening, leaking, rust-stained, or vertically displaced. The pattern and movement matter more than width alone.
Scaling or flaking at the surface
What it looks like: thin surface layers peel or break away, exposing coarse texture below.
What it can suggest: freeze-thaw and de-icer exposure, inadequate curing, an unsuitable mixture, finishing while bleed water was present, or a combination.
Next step: document area and depth before coating. A surface repair must bond to sound concrete and address ongoing exposure.
Spalling at a joint or edge
What it looks like: broken concrete along a joint, corner, or slab edge.
What it can suggest: incompressible debris in a joint, poor load transfer, impact, restraint, corrosion, or unsupported edges.
Next step: remove the hazard, determine whether movement continues, and preserve the joint’s intended function in the repair.
One panel has settled or heaved
What it can suggest: loss of support, poor drainage, frost movement, tree roots, utility work, or soil settlement.
Next step: measure vertical difference and monitor seasons. Grinding may reduce a trip edge but does not correct continuing support movement.
Fine map cracking or crazing
What it looks like: a shallow network of very fine surface lines, often more visible when the slab is wet or drying.
What it can suggest: surface shrinkage tied to finishing or curing. It may be mostly cosmetic, but deeper cracking, scaling, or movement changes the assessment.
Water-related clues on either material
- Ponding after ordinary rain: check slope, outlet elevation, settlement, and blocked drainage.
- Wet edges long after the centre dries: check roof discharge, snow storage, adjacent landscaping, and capillary or subsurface water.
- Fine material pumping from a joint or crack: repeated load may be moving water and base fines below the surface.
- Damage concentrated at a downspout or drain: fix the water route as part of the pavement repair.
- Seasonal opening and closing: temperature or frost movement may be involved; one warm-weather visit can miss it.
Choose urgency by consequence
Address promptly
- trip or fall hazards;
- loose pieces in traffic;
- rapid movement or widening;
- a hole exposing base or subgrade;
- water entering a building or creating an ice route;
- failed areas at an accessible route; or
- surface conditions that reduce vehicle control.
Plan and monitor
- stable, isolated hairline cracking;
- minor appearance variation without movement;
- an old repair that is sound but visibly different; or
- a small low spot that drains and is not changing.
Monitoring is an active choice: record dimensions and dates so “stable” has evidence behind it.
Match the treatment to the depth of failure
| Condition | Treatment family to investigate |
|---|---|
| Sound pavement with an isolated opening | Crack or joint treatment |
| Localized failure with firm surrounding material | Partial- or full-depth local repair |
| Surface aging over stable structure | Surface treatment or resurfacing, after repairs |
| Widespread structural movement or fatigue | Reconstruction of affected layers |
| Drainage-related distress | Drainage and elevation correction plus pavement repair |
Do not select from this table without confirming the condition. It organizes the conversation; it does not replace an on-site assessment.
Sources and further reading
- Asphalt Institute: Repair of asphalt parking lots and driveways
- Asphalt Institute: Engineering frequently asked questions
- NRMCA: Concrete in Practice reference library — includes technical notes on cracking, scaling, joints, finishing, and curing.
For a repeatable inspection routine, continue to the maintenance calendar and FAQ.