Is salt safe FOR YOUR SIDEWALK ?
Concrete shrinks as it cures, which causes shrinkage cracks. Settling and frost heaves also lead to cracks. Instead of risking random, meandering cracks, provide “control joints” for straight, invisible cracks to occur. You can plow control joints into fresh concrete with a groover (as shown here) or use a saw when the concrete is partially cured. On sidewalks, control joints are needed every 4 to 5 ft. On wide slabs like driveways, place them 10 to 12 ft. apart.
Groover Control joint