CN106220074A - A kind of for Marine reinforced concrete structure antiseptical fungicidal paint and coating processes thereof - Google Patents

Abstract

The invention discloses a bactericidal coating for anticorrosion of marine reinforced concrete and a coating process thereof. Portland cement is used as the matrix material, magnesium titanate is used as the photocatalytic bactericidal material, and sand is added, mixed with water, and stirred evenly to obtain the bactericidal anticorrosion coating. The invention has the advantages of wide source of raw materials, low cost, simple process, efficient and stable bactericidal performance and the like.

Description

A kind of bactericidal coating and its coating process for anticorrosion of marine reinforced concrete

technical field

The invention belongs to the field of inorganic coatings used on the surface of concrete structures, and in particular relates to a bactericidal coating used for anticorrosion of marine reinforced concrete and a coating process thereof.

Background technique

Entering the 21st century, my country has entered the era of great coastal economic development, and it is foreseeable that a large number of seaport terminals, cross-sea bridges, tunnels, offshore oil production platforms, etc. will use concrete structures in the future. Due to the long-term exposure to wind, sun and repeated beating of waves, the concrete structure in the wave base area tends to accumulate a large number of colonies and microorganisms on the surface of the concrete structure. How to effectively prevent the corrosion and damage of these bacterial colonies and microorganisms to concrete structures has gradually attracted the attention of the majority of scientific researchers and has become one of the focuses of academic research. Therefore, developing and using new materials and technologies to solve the corrosion problem of concrete structures is one of the most urgent tasks faced by scientific and technological workers in the field of civil engineering.

In terms of biological corrosion, biological sulfuric acid corrosion caused by T-sulfur oxidizing bacteria, Thiobacillus X, and silophilic bacteria is one of the common concrete corrosions. It flows and gradually deposits on the surface of the concrete structure to become attachments, and the sulfate ions in the attachments are reduced by sulfur-reducing bacteria to generate hydrogen sulfide gas. At the same time, the hydrogen sulfide gas is oxidized to produce stronger acidic sulfuric acid through complex biochemical reactions, thereby reducing the pH value of the surrounding environment. The hydrogen ions released by the dissolution of sulfuric acid diffuse into the interior of the concrete and contact the steel structure inside the concrete, resulting in corrosion of the concrete and steel bars, which seriously threatens the safety of the concrete building structure. At present, the commonly used bactericidal material is nano-titanium dioxide. Since nano-titanium dioxide can perform a "photocatalytic reaction", it generates chemical energy after being excited by light, and uses the generated chemical energy to carry out redox reactions. The basic principle of photocatalysis is to use nano-titanium dioxide as a photocatalytic material to generate highly oxidative holes or highly reactive hydroxyl radicals on the surface of nano-titanium dioxide under light radiation of a specific wavelength. These holes or free radicals can effectively contact and recombine with organic pollutants, viruses, and bacteria to produce a strong destructive effect, resulting in the degradation of organic pollutants and the killing of viruses and bacteria, thereby achieving the degradation of environmental pollutants and sterilization Antibacterial and antiseptic purposes. However, nano-titanium dioxide is subject to the influence of its preparation process and production capacity, as well as its potential hazards to the human body. It is urgent to develop a new type of substitute product, which is applied to the concrete anti-corrosion process that is not suitable for using nano-titanium dioxide.

In addition, there are many anti-corrosion methods for reinforced concrete blocks in the current prior art. For example, the invention patent with application number 201310232855.2 discloses a kind of anti-corrosion building concrete, including cement and admixture, and also has preservative and dispersant. The anti-corrosion building concrete of the invention is to make isobutyltriethoxysilane penetrate into the concrete, and react with the air exposed in the acidic or alkaline environment and the water molecules in the substrate to form a water-repellent treatment layer. Thereby inhibiting the ingress of moisture into the substrate. It must be added to the raw materials when the concrete mortar is prepared, that is, the preservative and dispersant, and cannot be used for the formed concrete blocks. The invention patent with application number 201510550106.3 discloses a modified acrylic coating concrete anticorrosion method, including the following steps: coating test; scaffold erection; concrete cleaning; concrete grinding; concrete repair and leveling; Lacquer; acrylic topcoat; curing. The essence of the invention is to seal the primer and topcoat with acrylic resin to form a strong protective barrier on the concrete surface, preventing water and carbon dioxide from entering the concrete block. However, this method does not work on concrete blocks soaked in water for a long time, because the bacteria on the surface still cannot be killed, and it is easy to enter the interior and cause corrosion to the steel bars.

Contents of the invention

The purpose of the present invention is to solve the problems existing in the prior art, and provide a new type of bactericidal coating and its coating process for marine reinforced concrete anticorrosion, so as to meet the antibacterial anticorrosion requirements of concrete soaked in seawater for a long time . The concrete technical scheme that the present invention adopts is as follows:

The bactericidal coating used for anticorrosion of marine reinforced concrete, the raw materials include: 20-35 parts by mass of magnesium titanate, 20-40 parts by mass of Portland cement, and 30-50 parts by mass of sand.

A kind of coating process of bactericidal anticorrosion paint, the steps are as follows:

Stir and mix 20-35 parts by mass of magnesium titanate and 20-40 parts by mass of Portland cement to obtain a dry mix A; add an appropriate amount of water to the dry mix A, and mix well to obtain a mixture B. After B is mechanically mixed, continue to stir while pouring 30-50 parts by mass of sand and 4-6 parts by mass of water into mixture B, and continue to mix to form paint C; dip paint C and coat evenly On the surface of the target concrete block and curing.

In the above technical solution, magnesium titanate is used as a photocatalytic material, which can generate hydroxyl radicals under light radiation of a specific wavelength, so as to achieve the purpose of sterilization, antibacterial and anticorrosion. The Portland cement and sand act as a binder, and the magnesium titanate is coated on the surface of marine reinforced concrete, thereby preventing the corrosion of biological sulfuric acid caused by microorganisms and maintaining the structural safety of the steel inside the concrete.

Preferably, the target concrete block is wetted with water before coating, so that the coating material can be stably and long-term fixed on the outer surface of the concrete block.

Preferably, the sand is pre-passed through an 80-mesh sieve. In addition, the weight ratio of the dry mix A to water is (2-4):1. The mesh size of the sand and the amount of water can affect the adhesion performance of the coating, and the adhesion performance is better under the above parameters. But for the specific environment, the corresponding ratio and parameters can be determined according to the experiment.

As a preference, the curing molding is specifically to solidify the coated concrete block in air at normal temperature.

In the photocatalytic anticorrosion coating of the present invention, magnesium titanate is used as a photocatalytic material, which can significantly increase the corrosion potential of concrete components by inhibiting the growth of bacteria, thereby slowing down the corrosion and damage of the concrete structure by biological sulfuric acid. Portland cement and sand in the present invention are used as binders and have a synergistic effect with magnesium titanate to further inhibit the growth of bacteria. The invention has the advantages of wide source of raw materials, low cost, simple process, efficient and stable bactericidal performance and the like. The invention is suitable for sterilization and anticorrosion of marine concrete structures soaked in seawater for a long time.

Description of drawings

FIG. 1 is a graph showing the change in self-corrosion potential with time of the blank control group and the experimental group in Example 3 of the present invention.

detailed description

The present invention will be further elaborated and illustrated below in conjunction with the accompanying drawings and specific embodiments. The technical features of the various implementations in the present invention can be combined accordingly on the premise that there is no conflict with each other.

The raw materials of the antiseptic coating for marine reinforced concrete include: 20-35 parts of magnesium titanate, 20-40 parts of Portland cement, and 30-50 parts of sand (both parts by mass). The coating process of bactericidal anticorrosion coating, the steps are as follows:

Pretreatment: Sand passes through a 80-mesh sieve, and the concrete test block is wetted with water.

Dry mixing: Pour the magnesium titanate and Portland cement weighed according to the proportion of the components into the container, put them in the mixer and stir for 10 minutes, and mix well to obtain the dry mix A.

Wet mixing: add an appropriate amount of water to the dry mix A, the weight ratio of the dry mix A to water is (2-4):1, put it in a mixer and mix well to obtain the mixture B. After mechanical mixing for 3 minutes, continue to stir, and pour the weighed sand and (4-6) parts of water into the mixture B, and continue to mix for 2 minutes to form the coating C;

Coating: Wet the pre-prepared concrete test block with water, dip paint C with a roller brush, and evenly coat the concrete surface to form test block D.

Curing: The test block D was left standing in the air at room temperature for 24 hours and then solidified and formed.

Following examples 1-3 are respectively the preparation of bactericidal coating:

Example 1

Pretreatment: Sand passes through a 80-mesh sieve, and the concrete test block is wetted with water.

Dry mixing: Pour 30 parts of magnesium titanate and 31 parts of Portland cement into a container, place them in a mixer and stir for 10 minutes to obtain a dry mixture A.

Wet mixing: according to the weight ratio of A: water = 3:1, add 20.3 parts of water to the dry mix A, put it in a mixer and mix well to obtain the mixture B. After mechanical mixing for 3 minutes, while stirring, pour 39 parts of sand and 4 parts of water into mixture B together, and continue mixing for 2 minutes to form coating C;

Coating: Dip paint C with a roller brush and spread it evenly on the concrete surface.

Curing: The test block is solidified after standing in the air at room temperature for 24 hours.

Example 2

Pretreatment: Sand passes through a 80-mesh sieve, and the concrete test block is wetted with water.

Dry mixing: Pour 25 parts of magnesium titanate and 28 parts of portland cement into a container, place them in a mixer and stir for 7 minutes to obtain a dry mixture A.

Wet mixing: according to the weight ratio of A: water = 2:1, add 26.5 parts of water to the dry mix A, put it in the mixer and mix well to obtain the mixture B. After 3 minutes of mechanical mixing, while stirring, pour 47 parts of sand and 4 parts of water into mixture B together, and continue mixing for 2 minutes to form coating C;

Coating: Dip paint C with a roller brush and spread it evenly on the concrete surface.

Curing: The test block is solidified after standing in the air at room temperature for 24 hours.

Example 3

Pretreatment: Sand passes through a 80-mesh sieve, and the concrete test block is wetted with water.

Dry mixing: Pour 33 parts of magnesium titanate and 33 parts of portland cement into a container, place them in a mixer and stir for 7 minutes to obtain a dry mixture A.

Wet mixing: According to the weight ratio of A: water = 2.5: 1, add 23.2 parts of water to the dry mix A, put it in the mixer and mix well to obtain the mixture B. After 3 minutes of mechanical mixing, while stirring, pour the weighed 42 sand and 4 parts of water into the mixture B, and continue to mix for 2 minutes to form the coating C;

Coating: Dip paint C with a roller brush and spread it evenly on the concrete surface.

Curing: The test block is solidified after standing in the air at room temperature for 24 hours.

In order to verify the effect of the coating and coating method of the present invention, an open circuit potential test and a photocatalytic sterilization experiment were carried out. The test results of the concrete blocks prepared in the above-mentioned Examples 1-3 are basically the same. For the sake of brevity, Example 3 is taken as an example below to illustrate. The specific methods and results are as follows:

1) Open circuit potential test

Take two experimental groups, each with two parallel concrete test blocks (40*40*40mm). The first group was used as a blank control group, and the two test blocks were not coated with the coating of the present invention (UC-01/02). The second group is used as an experimental group, and two test blocks are evenly coated with the photocatalytic anticorrosion coating (C-01/02) of the present invention. Each test block is put into four sealed cups separately, and poured into 400ml of sewage with bacteria (T-sulfur oxidizing bacteria, Thiobacillus X, Silicophage), and irradiated with a fluorescent lamp. Take out the test block regularly every day, and use the electrochemical workstation to do the open circuit potential test. The test results are shown in Figure 1.

It is well known that the higher the corrosion potential, the less likely it is to corrode. In the initial stage of immersion in sewage, the corrosion potential fluctuates greatly, and the corrosion potential tends to go in the direction of decreasing value (that is, the direction of corrosion). As the immersion time gets longer, the fluctuation of corrosion potential becomes smaller and smaller, and finally the corrosion potential tends to a stable value.

It can be found from the test chart that the corrosion potential interval of two concrete specimens (C-01/02) coated with the photocatalytic anticorrosion coating of the present invention is between -300--400mV, which is obviously higher than that of the concrete specimen not coated with the present invention. The corrosion potential of the two concrete specimens (UC-01/02) of the photocatalytic anticorrosion coating is -650—-750mV, and the potential difference between the two reaches about 250mV. Therefore, the photocatalytic anticorrosion coating of the present invention can significantly increase the corrosion potential of concrete components by inhibiting the growth of bacteria, thereby slowing down the corrosion and damage of concrete structures by biological sulfuric acid.

2) Photocatalytic sterilization experiment

Prepare the test block for the experiment: the concrete test block (40*40*5mm) is divided into two groups, the blank group concrete test block is not processed, and the surface of the experimental group concrete test block (40*40mm) is coated with the coating of the present invention.

Take the experimental test block and place it in a petri dish, with the 40*40mm side facing up, pour the pre-configured nutrient solution with colonies onto the test block, use ultraviolet light to irradiate the liquid with colonies, and wait for a while time, take a certain amount of liquid with colonies and drop them on a sterile plate, and count them under a microscope. The bactericidal ability of the coating is judged by the number of colonies. The lower the number of colonies, the stronger the bactericidal ability.

Supplementary explanation: 1, (because ultraviolet light itself just has very strong bactericidal effect, if use the ultraviolet lamp with stronger energy, can cover the photocatalytic sterilizing effect of coating test piece of the present invention, so this experiment selects medium excitation wavelength 365nm, medium Ultraviolet light with a power of 20W is used as a photocatalytic excitation light source) 2. Due to the large number of bacterial colonies, three bacteria that cause biological sulfuric acid corrosion were selected as experimental bacteria in this experiment: T-sulfur oxidizing bacteria, Thiobacillus X, and Silicophage.

Table 1 T-sulfur oxidizing bacteria culture solution test

Table 2 Thiobacillus X culture solution test

Table 3 Test of silophage culture medium

Note: unit cfu/ml: refers to the total number of bacterial communities contained in each milliliter sample

It can be seen from the above table that after 35 minutes of ultraviolet irradiation, the amount of viable bacteria on the four coating test pieces was reduced to 0.50, 0.67, and 0.55 respectively, only 31.6%, 36.8%, and 34.2% of the original amount of viable bacteria. . However, the amount of viable bacteria on the uncoated test piece as a control still remained at 1.5-1.8. It shows that the coated specimen can effectively kill the bacteria group.

The above-mentioned embodiment is only a preferred solution of the present invention, but it is not intended to limit the present invention. Various changes and modifications can be made by those skilled in the relevant technical fields without departing from the spirit and scope of the present invention. Therefore, all technical solutions obtained by means of equivalent replacement or equivalent transformation fall within the protection scope of the present invention.

Claims (7)

1. A bactericidal coating for anticorrosion of marine reinforced concrete, characterized in that the raw materials include: 20-35 parts by mass of magnesium titanate, 20-40 parts by mass of Portland cement, and 30-50 parts by mass of sand. 2. a coating process of bactericidal anticorrosion coating, is characterized in that, step is as follows: Stir 20-35 parts by mass of magnesium titanate and 20-40 parts by mass of portland cement, and mix them uniformly to obtain dry mix A; Add an appropriate amount of water to the dry mix A, and mix well to obtain a mixture B. After the mixture B is mechanically mixed, continue to stir while pouring 30-50 parts by mass of sand and 4-6 parts by mass of water into the mixture In B, continue mixing to form coating C; Dip paint C, apply it evenly on the surface of the target concrete block and cure it. 3. the coating technology of bactericidal anticorrosion coating as claimed in claim 2, is characterized in that described target concrete block is sprinkled with water before coating coating and wets. 4. the coating process of bactericidal anticorrosion paint as claimed in claim 2, is characterized in that, described sand passes through 80 mesh screens in advance. 5. The coating process of bactericidal anticorrosion coating as claimed in claim 2, characterized in that, the weight ratio of the dry mix A to water is (2-4):1. 6 . The coating process of the bactericidal anticorrosion coating as claimed in claim 2 , wherein the curing molding is specifically placing the coated concrete block in normal temperature air for solidification and molding. 7 . 7. A kind of magnesium titanate is used to prepare the purposes of antiseptic bactericidal coating of marine reinforced concrete.