E01C 5/223

Pavings made of prefabricated single units made of units composed of a mixture of materials covered by two or more of groups {[CPC: E01C5/008]} , [CPC: E01C5/02] - [CPC: E01C5/20] {except embedded reinforcing materials on prefabricated supporting or prefabricated foundation units, except coverings made of layers of similar elements}