aspro spacer. concrete spacer block are placed under reinforcement steel

architecture background bar beam being bent binding brown build builder cement column concrete concreting construction cover deform deformed design distance empty end engineering equipment fastened formwork foundation frame hard home house housing increase industrial industry infrastructure iron maintained manufacturing material mesh metal metallic nominal old outdoor parts rebar reinforced reinforcement reinforcing rod rust rusty site spacer special steel stirrups strong structure structures support tied used welding wire work