To prevent steel bars from rusting, what are the reasons why steel bars will rust?

This is absolutely not possible, the oil stain on the steel bar will affect the adhesion of the steel bar and concrete, and the construction code has clear regulations.

Generally, the floating rust of the steel bar can be used after the rust is removed, and the steel bar with serious rust and obvious corrosion dens needs to be re-identified for its strength, and it cannot be used if it does not meet the design requirements, or it is selected and used according to the identification strength decided by the design unit. Therefore, the steel bars should be overhead and stored indoors, and the steel bars at the construction site must be stored overhead, strengthened and covered and used as soon as possible.

No, diesel fuel will volatile. But diesel is expensive, and if it's covered, it's generally not rusty. Rust can be removed, polishing is more cost-saving, and it is conducive to welding. The diesel fuel did not volatilize cleanly. Affect welding.

Use it quickly before it doesn't rust.

The steel bar is not allowed to be painted, so as to prevent it from affecting its grip and wrapping force with concrete. The oil stain on the surface of the steel bar must be cleaned before construction.

In the shutdown project, if the steel bar is exposed, some practices are to brush the cement slurry, but it is not standardized, and the effect is not good.

Definitely not, it is absolutely not allowed to get oil on the steel bar. If it is only floating rust, it will not affect the use; If it is rusted, it is more difficult to deal with.

Waste diesel, big brother... That's a lot of money!!

It's better to cover the plastic sheet first, and basically leave it for a few days and it will be fine.

Even if it's a little rust, it's fine, it's just powdery floating rust, which doesn't affect the use and meets the requirements of the specification.

If you don't evaporate the oil when you use it, the supervisor won't let you ash it, which will definitely affect the bonding.

If the rust is too big and it becomes scaled, you can dig a trench, spread plastic cloth inside, pickle it with oxalic acid, or brush it with a wire brush.

If the rust reaches this point ... Your on-site management is too poor.,Downgrade it.。。。

Rust can occur in many corrosive-causing media, such as moist air, soil, industrial exhaust gases, etc.

Rust in steel can be broadly divided into two categories:

1. Chemical corrosion: refers to the rust caused by the direct chemical reaction between the surface of the steel and the surrounding medium. Steel is oxidized at high temperatures to form Fe3O4; Oxidation at room temperature to form FeO.

2. Electrochemical corrosion: The corrosion that occurs in the storage and use of construction steel mainly belongs to this category. The corrosion process is as follows:

1) In a humid environment, the surface of the steel is covered with a layer of electrolyte water.

Due to the unevenness of the surface composition or the shape of the stressed edge, the adjacent parts produce differences in electrode potential, and many microbatteries are established.

2) In the anode region, iron is oxidized into Fe ions and enters the water film; Because the water dissolves oxygen from the air, the oxygen placed in the cathode area is reduced to OHK; The two are combined to form ferrous hydroxide Fe(OH)2 that is not resistant to water.

3) Further oxidation will form loose and easy to peel off reddish-brown rusty iron hydroxide Fe(OH)3.

4) If there is an acid component in the water film, the cathode will be reduced to the separator. The corrosion will stop due to the polarization caused by the accumulation of hydrogen in the cathodo, but the dissolved oxygen in the water will combine with red to form water to remove the hydrogen accumulation, so the rust can continue. Because the concentration of separation in the water film increases.

Cathodic discharge is fast, corrosion is carried out quickly, so under the conditions of industrial atmosphere. Steel is more susceptible to corrosion.

It can be seen that the most common factors affecting the corrosion damage of steel are water and air that provides dissolved oxygen.

In reinforced concrete, the main causes of steel rust are:

1) The steel bars buried in the concrete are in an alkaline medium (the pH value of the newly poured concrete is about 125 or higher), and the oxidation protective film is also alkaline, so it will not corrode. But this protective film is susceptible to halogens.

Ions, especially chloride ions, cause rust to develop rapidly.

2) The water-cement ratio when pouring concrete.

Poor control, too much free water, after the hydration reaction, the free water evaporates, so that there are many fine pores on the surface of the concrete, due to the capillary phenomenon.

Ambient moisture will penetrate into the concrete along the capillary pores and corrode the steel bar.

3) The compactness of the concrete determines the speed of steel corrosion, the denser the concrete, the less easy the steel bar is to corrode, and vice versa, the steel bar corrodes faster. (4) Due to concrete curing.

Improper or insufficient thickness of the protective layer and cracks in the concrete under load are also the main causes of corrosion of the steel bars inside the concrete.

Answer, usually the main reasons are moisture, rain, sun, and open storage will lead to accelerated rusting of steel bars.

1. Manual rust removal.

This is a method of cleaning up the rust on the part of the steel bar, the specific operation is to use a scraper or a wire brush, manually rub it in the place where the rust needs to be removed, and then wipe it dry with a cleaning cloth, this method is time-consuming, and it is very troublesome, unless it is some local situation.

2. Mechanical rust removal.

If the number of corroded steel bars is large, you can only choose mechanical rust removal, automatic derusting machine or manual derusting machine are good choices, using the impact of the derusting machine to remove the rust marks attached to the surface of the steel bar.

3. Sandblasting and rust removal.

This rust removal method is a new technology that has become popular in recent years, using compressed air as the power to form a high-speed jet, spraying the spray at high speed on the material that needs to be derusted, removing rust marks on the surface, and obtaining a new cleanliness.

Spraying materials are divided into artificial abrasives and natural abrasives, quartz sand, river sand, copper ore, etc., because they contain free silicon and harmful heavy metals, there is a risk of carcinogenicity, and the use has been restricted, so the construction should be distinguished.

4. Chemical rust removal.

Use steel rust remover to remove rust marks on the surface, it should be noted that steel bar rust remover needs to be used with the original solution, spraying and brushing can not be regretted with water (otherwise it will be white ash), reducing the effect and affecting the appearance.

Summary. There is granular or flake rust on the surface of the building steel bar, which cannot be used, and the steel bar needs to be treated accordingly.

There is granular or flake rust on the surface of the building steel bar, which cannot be used, and the steel bar needs to be treated accordingly.

The degree of corrosion of the steel bar is divided into 5 categories. A: There is oxidation and rust on the surface of the building steel bar.

B: The surface of the steel is completely covered with oxide scale and almost no rust. c:

The steel surface has been corroded and part of the oxide scale has peeled off. D: The oxide scale has peeled off due to rust, or can be scraped off, and there is a small amount of pitting on the surface of the steel.

E: The surface of the steel that has been completely peeled off due to rust and has been widely pitted. In my opinion, except for Class A, the other four categories should be treated with rust removal in building construction.