Why do sidewalks have blocks, instead of being solid?

Question

Why do sidewalks have blocks, instead of being solid?

In: 205

Answer 1

A large single block of concrete will experience more stress from changes in the ground around it. The ground settles, freezes, tree roots grow, etc. It’s a guarantee that it will crack.

By pouring the concrete in blocks with a small gap, you give it room to flex. The gaps are literally called “expansion joints”.

If you didn’t include these intentional cracks when pouring, the concrete will create cracks for you. They’ll be uglier and far less uniform than the nice intentional straight ones.