Garage slabs take a lot of abuse. They have to support heavy cars and trucks and resist ice, dirt, salty water, de-icers, gasoline, motor oil, antifreeze, and other contaminants. Plus, since few garages are heated, they have to tolerate freeze/thaw conditions.
But a garage slab that has been carefully planned, installed, and cured should have no trouble providing years of crack-free performance in any climate, even under the toughest conditions.
Garage concrete contractors do this kind of work every day; adopt their attention to detail and you’ll meet their high standard of quality, without having to raise your prices.