Expansion joints in concrete

Nearly all concrete should have a type of joint ex specially paths and drive ways as they are prone  to excessive movement

The types of expansion joint can differ from job to job or person to person

Most common joint is the "old fooker joint" witch is troweled into the concrete in designated areas Witch leaves a small indentation in the finished surface

The now used expansion join is the saw cut mostly done by demo saw that has a blade used only for cutting concrete

It leaves a neat 3 mm wide cut in the surface that is more productive for cracking if a cures and is a lot neater For the eye to look at and in many instances you can make patterns to resemble paving  but is a bit costly to do so