Winters working from the outside in
At this elevation, a real freeze and thaw cycle repeats over the length of a winter rather than showing up as an occasional cold snap. Water that has soaked into the top of an exposed slab freezes, expands, and pushes against the surface from inside it. One winter rarely does much damage. Several winters of the same cycle, especially with salt in the mix, is how a sound looking driveway starts losing chips and flakes.
A mix or a finish that made it easier to happen
Not every case starts with weather. A mix poured without enough air entrainment gives freezing water nowhere to expand into except the surface itself. That decision is made at the plant, before the truck ever leaves, and it cannot be corrected later.
The other half of it is the finish. Bleed water rises out of fresh concrete for a while after it is placed, and a surface closed up before that water has finished coming up traps it under a sealed top skin. Working extra water into the top with the tools does the same kind of harm, and so does troweling the laitance back down into the surface instead of letting it leave. Any of those and the slab starts life with a weak layer on top that fails faster under the same winters everyone else's concrete handles fine.
Spalling next to its look-alikes
Spalling, scaling, and a pop out all describe chips and losses on a concrete surface, and people use the words loosely. Spalling is the broader term for the surface breaking away in chips or flakes. Scaling is the same failure spread thin and wide across a slab. A pop out is a small, localized cone-shaped chip, usually tied to one piece of aggregate near the surface rather than the whole top skin failing.
Where a driveway starts losing its surface first
Spalling rarely arrives evenly across a whole slab. It shows up first where water sits longest and where salt gets concentrated. The parking spot is usually the earliest patch, because a vehicle carries road slush and de-icer up the drive and drops it in the same square every time it is parked. Edges and the shoulders of control joints tend to be next, since there is more open surface there for water to get into and less concrete around it holding things together.
So does the strip that sits under a roof line with nothing carrying the runoff away, where the same line of the slab gets wet and refreezes all season. If your concrete is chipping in patches rather than everywhere at once, it is worth looking at what is happening above those patches before you decide the whole pour was bad.
Why an old driveway spalls faster than a new one
Concrete does not usually spall in its first winter. The surface has to be exposed to enough freeze and thaw cycles for water to have worked its way in and found a weak spot to push against, so an older slab that has been through several winters is naturally more likely to show it than one that went down last spring. That is also why spalling that shows up fast, within the first year, is worth a closer look. It usually means the mix, the finish, or the base gave it a head start it should not have had.
Either way, how deep the loss goes is what decides whether a slab is a resurfacing candidate or has to come out. That call is worked through on our tear out and replacement page.