CN102336555A - Modified polyester antirust coating for construction steel bars and construction method for modified polyester antirust coating - Google Patents

Abstract

Modified polyester antirust paint for building steel bars and its construction method, the composition of the modified polyester antirust paint for building steel bars in parts by mass: mixture: polymer polyester emulsion: water = 30~50: 25~40: 25~45; Among them, the mixture is Portland cement: silicon powder = 80~100: 0~20. Construction steps: ⑴Weigh ordinary Portland cement and silica fume, stir well to make a mixture; ⑵Weigh the mixture, polymer polyester emulsion, and water according to the mass ratio, stir for 3min~5min, and make building steel bars Modified polyester anti-rust coating slurry; (3) Spread the modified polyester anti-rust coating slurry evenly on the outer surface of building steel bars; (4) Put it in a sheltered and cool place for maintenance, and then use it for building construction. The modified polyester antirust paint of the invention can protect steel bars from rust spots when they are placed in the field for 6 months, and can increase the binding force between concrete and steel bars by 15% to 35%.

Description

Modified polyester antirust paint for building steel bars and its construction method

technical field

The invention relates to a modified polyester antirust coating for building steel bars and a construction method thereof, in particular to a modified polyester antirust coating for preventing steel bar corrosion on construction sites and a specific construction method thereof. It is a modified polyester anti-rust coating which can prevent the corrosion of steel bars on the construction site, can remove rust, and increase the binding force of steel bars and concrete, and the specific construction method of the coating on the construction site. This kind of coating is mainly used in construction projects involving reinforced concrete such as water conservancy projects, water transportation projects, industrial and civil construction projects, and transportation projects. It can significantly improve the quality of cast-in-place reinforced concrete, improve the durability of reinforced concrete and the stability of buildings, increase the service life of buildings, and reduce maintenance costs in the later period.

Background technique

In 2010, the data released by the American Society of Corrosion Engineers (NACE) showed that the total annual corrosion loss in the United States had reached 300 billion US dollars, accounting for 4.2% of the gross national product (GDP). Another report pointed out that infrastructure-based Corrosion damage of steel bars, its annual economic loss reaches 150 billion US dollars, accounting for 50% of the total corrosion loss and 2% of GDP. In addition, the annual repair cost of infrastructure caused by corrosion of steel bars in the United Kingdom is 5.5 billion pounds, and the annual corrosion loss in Australia is 25 billion US dollars. In particular, it should be noted that steel bar corrosion accounts for the main part. Asia, the Middle East and other regions also have a large amount of reinforced concrete. Reports of corrosion damage. In fact, steel bar corrosion damage has become a worldwide problem. In the International Conference on Concrete Durability, among many factors affecting the durability of concrete, steel bar corrosion was ranked first.

Since the founding of the People's Republic of my country, a large number of reinforced concrete structures have been built in water conservancy, highways, railways, and construction systems. Today, after decades of load operation of these reinforced concrete structures, there is no structural damage caused by steel corrosion. According to the exact statistical data, there must be a large amount of corrosion of steel bars in reinforced concrete. The premature destruction of buildings caused by steel bar corrosion has become a problem that is widely concerned in the engineering field and is becoming increasingly prominent.

The corrosion of reinforced concrete works mainly occurs in two stages. One is before concrete pouring, because the steel bars are exposed to the outside, affected by rain and weather, it is easy to produce large areas of rust spots; It is very common for large areas of rust to appear before concrete is poured. The second is that after the concrete is poured, during the service period of the reinforced concrete, the steel bars in the reinforced concrete are corroded due to various reasons. The corrosion of these two stages will reduce the service life of the reinforced concrete structure, and will increase the post-maintenance cost of the reinforced concrete structure at the same time.

Aiming at the damage caused by the corrosion of reinforced concrete, there are currently many methods to alleviate the corrosion damage of reinforced concrete. The commonly used methods are as follows: 1. Increase the thickness and compactness of concrete and protective layers, such as adding slag to the concrete to reduce Water-binder ratio, etc.; 2. Add a coating on the concrete surface to prevent the diffusion of harmful media to the concrete surface; 3. Add corrosion inhibitors during the concrete mixing process to reduce the corrosion rate of concrete during operation; 4. Electrochemical protection methods, Such as sacrificial anode method and applied current method, etc.; 5. Electrochemical desalination method, that is, to re-absorb the salt that has penetrated into the concrete; 6. Reinforcement surface treatment method, such as coating chemical latex on the surface of the rebar. Among the commonly used anti-corrosion treatment methods for steel bars at this stage, the first five methods are mainly used for the anti-corrosion of steel bars during the service period of reinforced concrete, but the corroded steel bars before concrete pouring cannot be treated; the sixth method belongs to the pre-treatment method for steel bars. The current construction method of chemical latex coating is complicated, and after the coating is dry and hard, the binding force between the steel bar and the concrete is reduced.

Contents of the invention

Aiming at the problems of steel bar corrosion and low grip force between steel bar and concrete caused by the asynchronous erection of steel bars and concrete pouring in current construction projects involving reinforced concrete, the invention provides a modified polyester antirust coating for building steel bars and the improved The specific construction method of non-toxic polyester anti-rust coating on the construction site. This anti-rust coating and its construction method are mainly used in construction projects involving reinforced concrete, which can solve the problems caused by the asynchronous erection of steel bars and concrete pouring in construction projects. Corrosion of steel bars, low binding force between steel bars and concrete, etc., can also remove rust spots on the surface of steel bars, improve the appearance quality of reinforced concrete, and significantly improve the quality of cast-in-place reinforced concrete, improve the durability of reinforced concrete and the stability of buildings , reduce the maintenance cost of the building during operation, and increase the service life of the building.

The modified polyester antirust coating in the invention can prevent the protected steel bars from rusting after being placed in the field for 6 months, and at the same time can increase the gripping force between the concrete and the steel bars by 15% to 35%.

The scheme for completing the first invention task of the present application is a modified polyester antirust coating for building steel bars, characterized in that the mass parts of the modified polyester antirust coating for building steel bars are composed as follows:

Mixture: polymer polyester emulsion: water = 30~50: 25~40: 25~45; wherein the composition of the mixture is, ordinary portland cement: silicon powder = 80~100: 0~20 .

The optimization scheme of the above ratio is, mixture: polymer polyester emulsion: water = 35 ~45: 30~35: 30~40. The best ratio is, mixture: polymer polyester emulsion: water = 35:35:30.

The optimized mass ratio of the mixture is ordinary Portland cement: silica fume = 90~95:5~10. The best mass ratio is ordinary Portland cement: silica fume = 92:8.

In the above scheme, the polymer polyester emulsion can be selected from: neoprene emulsion or polyvinyl chloride-vinylidene chloride emulsion or acrylate copolymer emulsion.

The silicon powder is dust with extremely fine particle size collected from the flue of a blast furnace for smelting silicon metal. The main component is glassy silica, which can make it have excellent properties such as high strength, abrasion resistance and durability when mixed into concrete.

The scheme of completing the 2nd invention task of the present application is: the above-mentioned construction steel bar modified polyester antirust coating is at the construction site specific construction method, it is characterized in that, the steps are as follows:

⑴. Weigh ordinary Portland cement and silicon powder according to a certain mass ratio, and stir them evenly in a dry mixer to make a mixture;

⑵. Weigh the mixture, polymer polyester emulsion, and water according to the mass ratio, put them into the forced mixer and stir for 3 minutes to 5 minutes to make a modified polyester antirust coating slurry for building steel bars;

⑶. Apply the prepared modified polyester antirust coating slurry evenly with a brush to the outer surface of the building steel bar, and the coating thickness is 1mm~2mm.

⑷. After smearing, the steel bars can be used on the construction site after 12 hours of curing in a sheltered and cool place.

After the mixture described in step (1) is weighed according to a certain mass, it should be stirred in a dry mixer for at least 3 minutes.

The "modified polyester antirust coating for building steel bars" of the present invention has the following notable features compared with the traditional antirust coating that does not apply the antirust coating:

1. Improve the binding force between steel bars and concrete

After the surface layer of the steel bar is coated with the "modified polyester anti-rust coating for building steel bars" described in the present invention, the gripping force of the steel bar and concrete can be increased by 15% to 35% compared with that of not applying the anti-rust coating, improving the strength of the steel bar. Integrity with concrete.

2. There is no rust on the surface of the steel bar

After the surface layer of the steel bar is smeared with the "modified polyester antirust coating for building steel bars" described in the present invention, after being placed in the natural environment for 6 months, the apparent quality of the steel bar is observed, and there is no rust spot on the surface of the steel bar, while the ordinary steel bar is placed in the natural environment. After only one month in the environment, the surface of the steel bar was severely corroded.

3. Remove rust spots on the surface of corroded steel bars

The pH value of the "modified polyester antirust coating for building steel bars" described in the present invention is 3.5-5.0, which is weakly acidic, and can chemically react with the rust spots on the surface of steel bars to remove the rust spots on the surface.

4. Improve the apparent quality of poured concrete

After the "modified polyester antirust paint for building steel bars" of the present invention is applied to the surface of the steel bars, the surface of the steel bars will no longer be corroded, so that there will be no rust spots on the surface of the steel bars and the yellow liquid mixed with water will penetrate into the cast-in-place reinforced concrete The surface improves the apparent quality of reinforced concrete. The laboratory and field test results are shown in Table 1.

Table 1 Laboratory and field test results of modified polyester antirust coatings for building steel bars

Detailed ways

Modified polyester anti-rust paint for building steel bars and its construction methods are as follows:

Example 1,

1. Weigh a certain amount of ordinary portland cement and silicon powder according to the ratio of mass ratio of 90:10, put them into a dry mixer, and stir for 3 minutes to make a mixture;

2. Weigh the mixture, polymer polyester emulsion and water according to a certain mass ratio, wherein the mixture accounts for 30 parts of the total mass, the polymer polyester emulsion accounts for 35 parts of the total mass, and water accounts for 35 parts of the total mass .

3. Put the weighed materials into the forced mixer and stir continuously for 4 minutes.

4. Put the stirred modified polyester anti-rust coating slurry into a container (such as a soft leather bucket), use a wire brush to remove rust spots or other impurities on the surface of the steel bar, and then use a brush to remove the modified polyester anti-rust coating slurry Brush evenly on the steel bar, after the surface of the steel bar is covered with modified polyester anti-rust paint slurry, put it in a sheltered and cool place for 12 hours.

Example 2,

1. Weigh a certain amount of ordinary Portland cement and silica fume according to the mass ratio of 92:8, put them into a dry mixer, and stir for 3 minutes to make a mixture;

2. Weigh the mixture, polymer polyester emulsion and water according to a certain mass ratio, wherein the mixture accounts for 40 parts of the total mass, the polymer polyester emulsion accounts for 25 parts of the total mass, and water accounts for 35 parts of the total mass .

3. Put the weighed material into the forced mixer and stir continuously for 3 minutes.

4. Put the stirred modified polyester anti-rust coating slurry into a container (such as a soft leather bucket), use a wire brush to remove rust spots or other impurities on the surface of the steel bar, and then use a brush to remove the modified polyester anti-rust coating slurry Brush evenly on the steel bars. After the surface of the steel bars is covered with the modified polyester anti-rust paint slurry, put it in a sheltered and cool place for 15 hours.

Example 3,

1. Weigh a certain amount of ordinary portland cement and silica fume according to the mass ratio of 85:15, put them into a dry mixer, and stir for 4 minutes to make a mixture;

2. Weigh the mixture, polymer polyester emulsion and water according to a certain mass ratio, wherein the mixture accounts for 35 parts of the total mass, the polymer polyester emulsion accounts for 25 parts of the total mass, and water accounts for 40 parts of the total mass .

3. Put the weighed material into the forced mixer and stir continuously for 3 minutes.

4. Put the stirred modified polyester anti-rust coating slurry into a container (such as a soft leather bucket), use a wire brush to remove rust spots or other impurities on the surface of the steel bar, and then use a brush to remove the modified polyester anti-rust coating slurry Brush evenly on the steel bar, after the surface of the steel bar is covered with modified polyester anti-rust paint slurry, put it in a sheltered and cool place for 14 hours.

Example 4,

It is basically the same as Example 1, but with the following changes: the ratio of ordinary Portland cement and silica fume in the mixture is 88:12.

In the modified polyester antirust paint slurry, the mixture accounts for 35 parts of the total mass, the polymer polyester emulsion accounts for 35 parts of the total mass, and the water accounts for 30 parts of the total mass.

Example 5,

It is basically the same as Example 2, but with the following changes: the ratio of ordinary Portland cement to silica fume in the mixture is 87:13.

In the modified polyester antirust paint slurry, the mixture accounts for 40 parts of the total mass, the polymer polyester emulsion accounts for 30 parts of the total mass, and the water accounts for 30 parts of the total mass.

Example 6 is basically the same as Example 3, but with the following changes: the ratio of ordinary Portland cement to silica fume in the mixture is 91:9.

In the modified polyester antirust paint slurry, the mixture accounts for 50 parts of the total mass, the polymer polyester emulsion accounts for 25 parts of the total mass, and the water accounts for 25 parts of the total mass.

Example 7 is basically the same as Example 1, but with the following changes: the ratio of ordinary Portland cement to silica fume in the mixture is 80:20.

In the modified polyester antirust paint slurry, the mixture accounts for 45 parts of the total mass, the polymer polyester emulsion accounts for 30 parts of the total mass, and the water accounts for 25 parts of the total mass.

Example 8 is basically the same as Example 2, but with the following changes: the ratio of ordinary Portland cement to silica fume in the mixture is 85:15.

In the modified polyester antirust paint slurry, the mixture accounts for 40 parts of the total mass, the polymer polyester emulsion accounts for 30 parts of the total mass, and the water accounts for 30 parts of the total mass. Rebar curing time is 20 hours.

Example 9 is basically the same as Example 3, but with the following changes: the ratio of ordinary Portland cement to silica fume in the mixture is 95:5.

In the modified polyester antirust paint slurry, the mixture accounts for 35 parts of the total mass, the polymer polyester emulsion accounts for 35 parts of the total mass, and the water accounts for 30 parts of the total mass. Rebar curing time is 25 hours.

Example 10 is basically the same as the above examples, but with the following changes: the ratio of ordinary Portland cement to silica fume in the mixture is 98:2.

In the modified polyester antirust paint slurry, the mixture accounts for 35 parts of the total mass, the polymer polyester emulsion accounts for 40 parts of the total mass, and the water accounts for 45 parts of the total mass.

Example 11 is basically the same as the above examples, but with the following changes: the ratio of ordinary Portland cement to silica fume in the mixture is 99:1.

Embodiment 12 is basically the same as the above embodiment, but with the following changes: the mixture is only made of ordinary Portland cement, without adding silica fume (that is, the ratio of ordinary Portland cement and silica fume in the mixture is 100: 0).

Claims (10)

1. A modified polyester antirust paint for building reinforcement, is characterized in that the mass parts of the modified polyester antirust paint for building reinforcement consist of the following: Mixing material: polymer polyester emulsion: water = 30~50: 25~40: 25~45; Wherein the mass composition of the mixture is Portland cement: silicon powder = 80~100:0~20. 2. The modified polyester antirust paint for building steel bars according to claim 1, wherein the mixture: polymer polyester emulsion: water = 35~45: 30~35: 35~40. 3. The modified polyester antirust coating for building steel bars according to claim 2, wherein the mixture: polymer polyester emulsion: water = 35:35:30. 4. The modified polyester antirust paint for building steel bars according to claim 1, wherein the mass ratio of the mixture is Portland cement: silicon powder = 90~95:5~10. 5. The modified polyester antirust paint for building reinforcement according to claim 4, wherein the mass ratio of the mixture is Portland cement: silicon powder = 92:8. 6. The modified polyester antirust paint for building reinforcement according to any one of claims 1 to 5, wherein the polymer polyester emulsion is selected from: neoprene emulsion or polyvinyl chloride-vinylidene chloride emulsion or acrylate copolymer emulsion. 7. a construction method of modified polyester antirust paint for building reinforcement as claimed in claim 1, is characterized in that, the steps are as follows: ⑴. Weigh ordinary Portland cement and silicon powder according to a certain mass ratio, and stir them evenly in a dry mixer to make a mixture; ⑵. Weigh the mixture, polymer polyester emulsion, and water according to the mass ratio, put them into the forced mixer and stir for 3 minutes to 5 minutes to make a modified polyester antirust coating slurry for building steel bars; ⑶. Apply the prepared modified polyester anti-rust coating slurry evenly on the outer surface of the building steel bar with a brush; ⑷. After the painted steel bars are kept in a sheltered and cool place, they can be used in construction sites. 8. The construction method of modified polyester antirust paint for building steel bars according to claim 7, characterized in that, after the mixture described in step (1) is weighed by a certain mass, it will be stirred in a dry mixer for at least 3min. 9. the construction method of modified polyester antirust coating for building reinforcement according to claim 7, is characterized in that, the modified polyester antirust coating that is applied to the outer surface of building reinforcement described in step (3), thickness is 1mm～ 2mm. 10. according to the construction method of claim 7 or 8 or 9 described building reinforcement modified polyester antirust coatings, it is characterized in that, in step (4), the steel bar of modified polyester antirust coatings after described smearing is put away from the wind , The curing time in the shade is at least 12 hours.