Rust on Reinforcing Steel

which ASTM specification

Haha yeah I remember all those times in the field when I’d hose off rebar...not!

Thank you. I live in the Malaysia and I'm currently doing a residential project using reinforced concrete. We are under Restricted Movement Order (RMO) due to Covid-19. I was worried about this as the RMO started when I was about to fill the first floor with concrete and the site has stopped for a month now. The formwork and Rebars are all exposed to the elements which got me really worried about the effect it has. After watching this, I'm more assured that it actually increases the bond of the bar to the concrete. I measured a 6% nominal weight deterioration for a 10mm bar would be 9.7mm. That's a low margin. I will check the bar size once the RMO is lifted.