How can unreinforced concrete pavement function without mesh reinforcement?

1. How can unreinforced concrete pavement function without mesh reinforcement?
For concrete carriageway, it is normally classified into two types: reinforced and
unreinforced concrete pavement. The reinforcement in reinforced carriageway (in the form
of mesh) is used for controlling cracking. Then one may query how unreinforced pavement
can control cracking without the use of mesh reinforcement. To answer this question, one
should pay attention to the features of unreinforced concrete pavement. In accordance with
Highways Standard Drawing No. H1109, an approximately 3mm wide groove with a depth
of about one-third to one-fourth of slab thickness is designed with a regular spacing
(normally 5m). The grooves are designed to be too narrow for stones to fall into when the
cracks are open due to concrete contraction. The sectional area in which the groove is
located is a plane of weakness and thus this groove acts a potential crack-inducing device
in which any potential cracks due to shrinkage and thermal contraction may form.
Consequently, the cracks are formed at the base of the groove and thus it would not cause
any unpleasant visual appearance on the exposed surface of unreinforced concrete
pavement.