Product matched to the temperature, not to habit.

Most de-icing in this business is done by habit. One product, one rate, one bag on the truck all winter, spread the same way at 28°F and at 2°F.

That's how you get an untreated lot at the coldest hour of the storm, and a spalled slab in April. Neither is a snow problem. Both are a product-selection problem.

Anti-icing vs. de-icing — two different jobs

Anti-icing happens before the snow. A treatment laid on dry pavement ahead of a storm makes it much harder for snow and ice to bond to the surface. When the plow comes through, it comes up clean instead of leaving a welded layer behind. Pre-treatment is the cheapest thing on a snow contract that actually reduces work — and it only exists if somebody was watching the forecast two days out.

De-icing happens after. Snow is cleared first, then product is applied to break the residual bond and hold the surface. Product on top of six inches of unplowed snow doesn't melt the snow; it makes slush, and slush refreezes into something harder than what you started with. Clear first. Then treat.

Temperature drives the chemistry

Every de-icer has a temperature below which it stops doing useful work in a real-world application rate.

• Sodium chloride (rock salt) is the workhorse — cheap, widely available, and effective through the mild end of a Colorado winter. As pavement temperature drops it slows down sharply, and near the bottom of its range it's spreading cost with very little melt to show for it.
• Magnesium chloride and calcium chloride keep working at colder pavement temperatures than rock salt does. Minnesota's Smart Salting guidance — the reference most of this industry actually uses — puts rock salt's lowest practical melting temperature around 15°F, magnesium chloride near −10°F, and calcium chloride near −20°F. Those are working numbers, not the eutectic temperatures printed on the bag, which are much colder and effectively meaningless in a parking lot.
• Blends and treated salts — rock salt coated or blended with a chloride brine or an organic additive — push the working range colder than straight salt while keeping cost in check.
• Acetates and formates are chloride-free. They're the standard on airfields precisely because they're gentler on metal, and they're the honest answer on structural surfaces where chloride corrosion of reinforcing steel is a real concern. They cost more, and they carry their own environmental tradeoff.
• Sand doesn't melt anything. Sand is traction, not chemistry, and it's what you use when it's genuinely too cold for a de-icer to do anything but sit there. On the coldest Front Range mornings, sand on a walk is the difference between grip and no grip.

The practical version: the crew checks pavement temperature — not air temperature — and puts down the product that works at that number. Which product, at what rate, on which surfaces, at what temperature, all of it goes in the log.

What this does to your concrete

De-icers do not "eat" concrete the way people say. What actually happens is mostly physical: the melt water saturates the pore structure, and then it freezes again. Repeated freeze-thaw cycling inside a saturated slab is what scales the surface off in sheets. That's why properly air-entrained concrete — concrete with a deliberate microscopic bubble structure that gives freezing water somewhere to expand into — holds up so much better than concrete that isn't.

Two things are also chemically true and worth knowing:

• Magnesium chloride and calcium chloride can chemically attack cement paste, forming expansive compounds inside the slab. It's a real mechanism, not a myth.
• Chlorides drive corrosion of reinforcing steel. On a slab-on-grade in a parking lot, that's a long-term issue. On a parking structure or a bridge deck, it's the issue.

And the one nobody wants to hear: new concrete is the vulnerable concrete. A slab in its first winter has not developed full strength and has not gone through a dry-out cycle. Ordinary practice is to keep de-icers off fresh concrete through that first winter and use sand for traction instead. If you poured a new walk, a new dock apron, or a new entry this year, tell us before the season starts — we'll route sand to it and keep the chlorides off. The full chemistry is in ice melt products and what they do to concrete.

Rate discipline

Over-application is the actual problem in this industry. More product does not melt more ice past a point — it just runs off into your landscape beds, loads chloride into the soil and the storm drain, tracks into the lobby on everyone's shoes, and hands you a bigger invoice for the privilege.

We spread to a rate, we spread to the pavement temperature, and we write down what we did. Then you have a record — of the ice, the response, and the product. That record is the point.