A rusty assembly must be emptied, my experience.
Rust is a very extensive topic, there are many types and much attention must be paid to it, because neglecting this variable can cause many accidents, therefore, the steel in the open, exposed to rain, heat or cold, among Other conditions such as the case of reinforced steel under construction that I show you, must be evaluated to take the appropriate respective measures.
The respective question would be, should you clean the steel bars with a steel brush before pouring with cement; When you observe the armed bars and touch them, you notice how a very soft brown powder comes off, common sense tells you that it is better to clean them with a wire brush, since if it is emptied with the oxide film it can remove the grip between the bar and cement.
To discern the matter, consult the American Standard ACI 318-14, in chapter 26 article 26.6.6.1.1, where it says:
“(b) reinforcement not pre-stressed with rust, flake, or a combination of both should be considered satisfactory if the minimum dimensions (includes the height of the ribs of the corrugation) and the weight of a sample cleaned by hand using a brush of steel wire meets applicable ASTM standards. ”
Furthermore, R26.6.1.28b) tells us:
“The specified limits of oxidation are based on the tests performed (kemp et al 1968) and on the review of previous tests and recommendations: Kemp et al (1968) provide guidance regarding the effects of oxidation and from flaking on the characteristics of corrugated rebar: Research has shown that a normal amount of oxide increases the bond between concrete and reinforcement. " Generally, through normal rough handling, loose rust is lost and can impair the bond between concrete and reinforcement.
Reinforcements Uncleaned
It is necessary to limit something, that the norm mentions the bars in a loose state, prior to being used; and when handling it, the powder mentioned above will be lost with handling in the reinforcement assembly; in my case the reinforcement is already assembled, there will be no more manipulation and in this sense the loose dust has to be removed, as specified by the norm.
Refuerzos limpios
Good friends, it all depends on the conditions that your reinforcement element finds, in my case I will only clean them of that loose dust.