TWI824553B - Cement doped with reactive ultra-fine fly ash and corrosion prevention method thereof - Google Patents

Abstract

The present invention discloses cement doped with reactive ultra-fine fly ash and manufacturing method thereof. The cement doped with reactive ultra-fine fly ash is composed of a cement material and an ultra-fine fly ash material. The ultra-fine fly ash material is doped into the cement material, and the wt% of the ultra-fine fly ash material of the cement material ranges from 5%-30%. Therefore, the compressive strength of the cement is significantly increased and the water absorption rate of the cement may be decreased. On the other hand, the present invention is used for protect at least one metal building material to prevent and reduce the corrosion of the at least one metal building material.

Description

Concrete doped with ultrafine reactive fly ash and its anti-corrosion method

The invention is a concrete doped with ultrafine reactive fly ash and a preparation method thereof. In particular, it refers to a technology that can be filled with ultrafine reactive fly ash materials by doping ultrafine reactive fly ash materials in concrete materials. A void in the concrete material. Accordingly, various physical and chemical properties of concrete doped with ultrafine reactive fly ash can be extremely effectively improved.

For modern buildings, cement can be said to be the most important part. Generally speaking, when cement is used in construction, the most important factors are the cement composition ratio and other factors. In the production of cement floor, most of it depends on the preparation of cement mortar to determine the characteristics of cement application.

Regarding the issue of cement materials, most cement used in buildings is required to have an extremely high degree of solidity. In addition, the water absorption rate of the cement itself should also be reduced. The reason is that cement with low water absorption can prevent corrosion and other problems on various objects buried in it, including various cable lines, pipelines, steel bars, etc.

However, the internal structure of the cement after solidification will actually approach a fine thorn petal-like structure. Please refer to Figure 2 first. Figure 2 is a scanning electron microscope diagram of the internal structure of conventional concrete. From Figure 2, it can be clearly seen that conventional concrete actually has many irregular structures inside; these structures are very likely to cause potential structural dangers or cause more pores and thus water absorption problems.

In view of the fact that many buildings are built in coastal areas or areas with high humidity, corrosion often occurs in these areas. The so-called corrosion is the phenomenon that occurs when materials are exposed to the environment and come into contact with water, soil and air.

Metal building materials such as mild steel materials are widely used in various public facilities and buildings. Therefore, if concrete cannot reduce the intrusion of various water or air, the service life of these metal building materials such as internal steel bars, external steel plates and steel beams, and even structures that may be immersed in water such as bridge piers, will face many difficulties and challenge.

In addition, with the booming development of offshore power generation units and offshore construction in recent years, the requirements for the corrosion resistance protection of materials have become more stringent. The reason is that the increase in chloride ion (Cl ^- ) concentration in the marine environment accelerates the corrosion process of metal building materials.

In order to solve the problems mentioned in the prior art, the present invention provides a concrete doped with ultrafine reactive fly ash and a preparation method thereof.

Specifically, the concrete doped with ultrafine reactive fly ash of the present invention includes a concrete body material and an ultrafine reactive fly ash material. The ultrafine reactive fly ash material is mixed into the concrete body material, and the ultrafine reactive fly ash material accounts for 5%-30% of the weight percentage of the concrete body material. Among them, the ultrafine reactive fly ash material includes oxides of silicon, aluminum, iron and calcium. The aforementioned concrete doped with ultrafine reactive fly ash is used to embed at least one metal building material.

Furthermore, the present invention further provides the aforementioned anti-corrosion method using concrete doped with ultrafine reactive fly ash.

Step (A) is first performed to provide a fly ash powder containing a plurality of fly ash spheres. Next, step (B) uses a calcination method to process the plurality of fly ash spheres to break the plurality of fly ash spheres to obtain an ultrafine reactive fly ash material.

The next step (C) is to mix the ultrafine reactive fly ash material in a proportion of 5% to 30% by weight of the concrete bulk material. Step (D) can produce the ultrafine reactive fly ash-doped concrete as described above. Therefore, in step (E), the concrete doped with ultrafine reactive fly ash can be wrapped with at least one metal building material.

Through the technology of the present invention, the strength of concrete can be effectively improved and its water absorption rate can be reduced. Further improve the sturdiness of buildings and prevent risks such as oxidation or rust in various structures covered by concrete.

In order to understand the technical features and practical effects of the present invention and implement it according to the contents of the description, the preferred embodiment as shown in the drawings is further described in detail as follows:

The concrete doped with ultrafine reactive fly ash in this embodiment includes concrete body material and ultrafine reactive fly ash material. The ultrafine reactive fly ash material is mixed into the concrete body material, and the ultrafine reactive fly ash material accounts for 5%-30% of the weight percentage of the concrete body material. Among them, the ultrafine reactive fly ash material contains oxides of silicon, aluminum, iron, and calcium. In other possible embodiments, in addition to the aforementioned oxides, the ultrafine reactive fly ash material further includes magnesium, sodium and potassium oxides. In this embodiment, the concrete doped with ultrafine reactive fly ash is used to wrap at least one metal building material. The at least one metal building material is steel bars, steel frames, steel plates, steel beams, pipelines or combinations thereof.

Among them, the best implementation of this embodiment is based on the ultrafine reactive fly ash material accounting for 20% of the weight percentage of the concrete body material. Specifically, the ultrafine reactive fly ash material used in this embodiment is made of fly ash powder containing a plurality of fly ash spheres, and the plurality of fly ash spheres are processed by a calcination method to make the plurality of fly ash spheres The material obtained after rupture.

Furthermore, the particle size of the aforementioned fly ash powder is between 1 and 20 microns (μm); the particles of the ultrafine reactive fly ash material in this embodiment obtained after being heated in a specific temperature range by calcination means are spheres. And the particle size of the spheres is between 0.1 and 5 microns (μm).

In this embodiment, fly ash powder is a by-product of coal-fired power generation in thermal power plants, and its main components are silicon dioxide (SiO ₂ ), aluminum oxide (Al ₂ O ₃ ), and calcium oxide (CaO). Of course, the fly ash powder may also contain heavy metal elements due to different compositions of coal combustion.

For this reason, the ultrafine reactive fly ash material in this embodiment includes oxides of silicon, aluminum, iron and calcium, wherein the oxide of silicon is silicon dioxide (SiO ₂ ); the oxide of aluminum is alumina. (Al ₂ O ₃ ) and the iron oxide is hematite (Fe ₂ O ₃ ).

Further, in other possible embodiments, when the ultrafine reactive fly ash material further includes magnesium, sodium and potassium oxides, the atomic proportion of the ultrafine reactive fly ash material in this embodiment is based on X-ray energy. Energy-dispersive X-ray spectroscopy (EDS) analyzes ultra-fine reactive fly ash materials. The atomic proportions of this embodiment include weight percentages of 67-75% oxygen atoms (O), 16-20% silicon atoms (Si), 4.5-6% aluminum atoms (Al), and 1-3% calcium. atoms (Ca), 0.5-2% sodium atoms (Na), 0.8-1.6% potassium atoms (K), 0.8-1.6% iron atoms (Fe) and 0.2-0.6% magnesium atoms (Mg).

Specifically, the relatively accurate atomic proportions of this embodiment include 71.28% oxygen atoms (O), 17.65% silicon atoms (Si), 5.23% aluminum atoms (Al), 1.98% calcium atoms (Ca), and 1.19% sodium atoms (Na), 1.16% potassium atoms (K), 1.15% iron atoms (Fe) and 0.37% magnesium atoms (Mg).

However, each experiment or test conditions and equipment may cause errors. Therefore, the above-mentioned atomic proportion data in this embodiment may have an error that increases as the proportion decreases. Therefore, depending on the proportion of each atom, if the proportion of atoms falls within the following error interval, it should still fall within the scope of the present invention.

First of all, for major elements (such as oxygen atoms (O)) with an atomic weight percentage of more than 20%, the relative error tolerance should be less than or equal to plus or minus 5%. For elements whose atomic weight percentage is between 3-20% (such as silicon atoms (Si) and aluminum atoms (Al)), their relative error tolerance should be less than or equal to plus or minus 10%. Next, for elements whose atomic weight percentage is between 1-3% (such as calcium atoms (Ca), sodium atoms (Na), potassium atoms (K) and iron atoms (Fe)), the relative error tolerance value is Should be less than or equal to plus or minus 30%. Finally, for elements whose atomic weight percentage is between 0.5-1% (such as magnesium atoms (Mg)), their relative error tolerance should be less than or equal to plus or minus 50%.

Accordingly, all ultrafine reactive fly ash materials whose atomic weight percentage content falls within the corresponding interval error should fall within the scope of the present invention.

Finally, in order to verify that the ultrafine reactive fly ash material in this embodiment can fill the pores in the concrete body material, so that the entire concrete structure doped with ultrafine reactive fly ash is denser and has fewer pores, please also refer to the figure. 1 and Figure 2. Figure 1 is a scanning electron microscope picture of the internal structure of concrete doped with ultrafine reactive fly ash according to an embodiment of the present invention; Figure 2 is a scanning electron microscope picture of the internal structure of conventional concrete.

Among them, the scanning electron microscope pictures in Figures 1 and 2 were both taken at a magnification of 10,000 times. In Figure 1, the spherical material filled in the concrete body is the ultra-fine reactive fly ash material referred to in this embodiment.

By analyzing and comparing the electron microscopy images of Figures 1 and 2 using ImageJ ^TM software, it can be found that the porosity of the concrete doped with ultrafine reactive fly ash in this example is between 11.38% and 5.71%. By comparison, Figure The porosity of the conventional concrete in 2 is as high as 14.82%. When the ultrafine reactive fly ash material accounts for 20% of the weight percentage of the concrete body material, the porosity of the best embodiment is only 5.71%.

At the same time, comparing this embodiment with conventional concrete in Figures 1 and 2, the compressive strength of the concrete doped with ultrafine reactive fly ash in this embodiment is between 392.3-461.0 kgf/ ^cm2 . Similarly, when the ultrafine reactive fly ash material accounts for 20% of the weight percentage of the concrete body material, the compressive strength of the best embodiment is as high as 461.0 kgf/cm ² . However, the conventional concrete has only 363.7 kgf/cm ² .

Regarding the water absorption rate, compare this embodiment with conventional concrete in Figures 1 and 2. The water absorption rate of the concrete doped with ultrafine reactive fly ash in this embodiment is between 0.9% and 1.4%. . When the ultrafine reactive fly ash material accounts for 20% of the weight percentage of the concrete body material, the water absorption rate of the best embodiment is 0.9%. It can be seen that the ultra-fine reactive fly ash material effectively fills the pores in the concrete body material and further prevents water vapor from being sucked into the concrete body material. In comparison, the conventional concrete in Figure 2 has a high content of 1.7%.

Next, please refer to Figure 3. Figure 3 is a flow chart of an anti-corrosion method for concrete doped with ultra-fine reactive fly ash according to an embodiment of the present invention. As shown in FIG. 3 , the method for preparing concrete doped with ultrafine reactive fly ash in this embodiment first performs step (A) to provide a fly ash powder containing a plurality of fly ash spheres.

Next, step (B) uses a calcination method to process the plurality of fly ash spheres to break the plurality of fly ash spheres to obtain an ultrafine reactive fly ash material. In this embodiment, the processing temperature range of the calcination means is between 260 and 1100 degrees Celsius.

Step (C) is then performed, and the ultrafine reactive fly ash material is mixed in a proportion of 5% to 20% by weight of the concrete bulk material. Finally, step (D) can produce the ultrafine reactive fly ash-doped concrete as described above. Finally, in step (E), the concrete doped with ultrafine reactive fly ash can be wrapped with at least one metal building material.

Among them, in step (C), the ultrafine reactive fly ash material accounts for 20% of the weight percentage of the concrete body material, which is optimal.

Through the technology of this embodiment, the solidity of concrete can be effectively improved and its water absorption rate can be reduced. Further improve the sturdiness of buildings and prevent risks such as oxidation or rust in various structures covered by concrete.

Furthermore, in order to verify that the concrete doped with ultrafine reactive fly ash in this embodiment can effectively have good anti-corrosion effect on various metal building materials such as steel bars, steel frames, steel plates or steel beams, this embodiment uses three different The steel bars in this state were respectively embedded in the conventional concrete in Figure 2 and the concrete doped with ultra-fine reactive fly ash in this embodiment of Figure 1 for testing.

Among them, the three different states of steel bars are untreated, hot-dip galvanized and epoxy resin. The detailed grouping is shown in Table 1 below: Group Covering body Rebar A custom concrete No processing B custom concrete hot dip galvanized C custom concrete Epoxy resin D Concrete doped with ultrafine reactive fly ash (20% by weight of ultrafine reactive fly ash) No processing E Concrete doped with ultrafine reactive fly ash (20% by weight of ultrafine reactive fly ash) hot dip galvanized F Concrete doped with ultrafine reactive fly ash (20% by weight of ultrafine reactive fly ash) Epoxy resin Table 1

Among them, the steel bars in this embodiment are hot-dip galvanized by first soaking the steel bars in zinc chloride (ZnCl ₂ ) and ammonium chloride (NH ₄ Cl) in a weight ratio of 6:4. The steel bars were then subjected to a zinc bath at a temperature of 450 degrees Celsius for 2 minutes, and then the steel bars were cooled at a constant temperature in a water tank at a temperature of 60 degrees Celsius to obtain steel hot-dip galvanized steel bars with a galvanized layer thickness of 50 microns (groups B and E).

For the epoxy resin steel bars in this embodiment, the steel bars are first sprayed with epoxy resin (Epoxy) evenly through an air compressor and a spray gun. Finally, an epoxy resin layer with a thickness of 11 microns was formed outside the steel bars (groups C and F).

The above-mentioned groups A-C are formed by grouting with conventional concrete mixed with mortar, and at least part of the steel bars of each group are embedded therein. Groups D-F were grouted with the concrete doped with ultrafine reactive fly ash of this embodiment (ultrafine reactive fly ash weight percentage: 20%), and finally at least part of the steel bars of each group were embedded in it.

Next, the test subjects in groups A-F were cured for 56 days. The relevant curing method is to soak the test objects in saturated lime water for curing. Next, since the corrosion resistance of concrete needs to simulate the corrosion conditions of the external environment, in this example, the test objects of groups A-F are first immersed in a sodium chloride (NaCl) solution with a concentration of 3.5% by weight to simulate the corrosion of sea water. environment.

Then, connect the positive electrode of the power supply to the steel bar; connect the cathode to an ungrounded metal object (such as an iron mesh placed on an accelerated corrosion tank), and then energize it with a fixed current density (0.5 mA/cm²) to accelerate corrosion. In this embodiment, the power is turned off once every 24 hours, and the open circuit potential value of the steel bars in groups A-F is measured after 240 hours to examine their corrosion resistance.

Among them, the larger the open circuit potential value means that the coating of this group has extremely good coating and denseness, and can effectively prevent gas and liquid from contacting the embedded steel bar body. Specifically, the open circuit potential value results of the final AF group in this embodiment are shown in Table 2 below: Group Covering body Rebar Open circuit potential value (mV) A custom concrete No processing -502 B custom concrete hot dip galvanized -675 C custom concrete Epoxy resin -1208 D Concrete doped with ultrafine reactive fly ash (20% by weight of ultrafine reactive fly ash) No processing -425 E Concrete doped with ultrafine reactive fly ash (20% by weight of ultrafine reactive fly ash) hot dip galvanized -576 F Concrete doped with ultrafine reactive fly ash (20% by weight of ultrafine reactive fly ash) Epoxy resin -966 Table 2

After testing, it was found that comparing group A and group D; comparing group B and group E; and comparing group C and group F, it can be found that no matter which group the results are, the coating is made of ultra-doped materials. When using concrete with fine reactive fly ash (ultra-fine reactive fly ash weight percentage 20%), a higher open circuit voltage value can be obtained.

Therefore, no matter what kind of metal building materials have been processed (such as the steel bars in this embodiment), when the concrete doped with ultrafine reactive fly ash in this embodiment is selected as the covering body, it has been proven that the ultrafine reactive fly ash in this embodiment is doped. Fly ash-type concrete has good density protection, can effectively block the transmission of electrons and destructive ions, and slow down corrosion.

However, the above are only preferred embodiments of the present invention, and should not be used to limit the scope of the present invention. That is, simple changes and modifications made based on the patent application scope and description content of the present invention still belong to the present invention. within the scope covered.

(A)~(E): Steps

Figure 1 is a scanning electron microscope diagram of the internal structure of concrete doped with ultrafine reactive fly ash according to an embodiment of the present invention.

Figure 2 is a scanning electron microscope image of the internal structure of conventional concrete.

Figure 3 is a flow chart of the anti-corrosion method of concrete doped with ultrafine reactive fly ash according to an embodiment of the present invention.

Claims (18)

A concrete doped with ultrafine reactive fly ash, including: a concrete body material; an ultrafine reactive fly ash material doped in the concrete body material, and the ultrafine reactive fly ash material accounts for 10% of the concrete body material 5%-30% by weight; wherein, the ultrafine reactive fly ash material contains silicon, aluminum, iron and calcium oxides; wherein, the concrete doped with ultrafine reactive fly ash is embedded with at least one metal building material ; The porosity of the concrete doped with ultrafine reactive fly ash is between 11.38% and 5.71%. The concrete doped with ultrafine reactive fly ash as described in claim 1, wherein the ultrafine reactive fly ash material accounts for 20% of the weight percentage of the concrete bulk material. The concrete doped with ultrafine reactive fly ash as described in claim 1, wherein the silicon oxide is silicon dioxide (SiO ₂ ). The concrete doped with ultrafine reactive fly ash as described in claim 1, wherein the aluminum oxide is alumina (Al ₂ O ₃ ). The concrete doped with ultrafine reactive fly ash as described in claim 1, wherein the iron oxide is hematite (Fe ₂ O ₃ ). The concrete doped with ultrafine reactive fly ash as described in claim 1, wherein the particles of the ultrafine reactive fly ash material are spheres. The concrete doped with ultrafine reactive fly ash as described in claim 6, wherein the particle size of the sphere is between 0.1 and 5 microns (μm). The concrete doped with ultrafine reactive fly ash as described in claim 1, wherein the ultrafine reactive fly ash material further contains oxides of magnesium, sodium and potassium. The concrete doped with ultrafine reactive fly ash as described in claim 8, wherein the atomic proportion of the ultrafine reactive fly ash material includes 67-75% oxygen atoms (O) and 16-20% silicon atoms ( Si), 4.5-6% aluminum atoms (Al), 1-3% calcium atoms (Ca), 0.5-2% sodium atoms (Na), 0.8-1.6% potassium atoms (K), 0.8-1.6 % iron atoms (Fe) and 0.2-0.6% magnesium atoms (Mg). The concrete doped with ultrafine reactive fly ash as described in claim 1, wherein the porosity of the concrete doped with ultrafine reactive fly ash is 5.71%. The concrete doped with ultrafine reactive fly ash as described in claim 1, wherein the compressive strength of the concrete doped with ultrafine reactive fly ash is between 392.3-461.0kgf/cm ² . The concrete doped with ultrafine reactive fly ash as described in claim 11, wherein the compressive strength of the concrete doped with ultrafine reactive fly ash is 461.0kgf/cm ² . The concrete doped with ultrafine reactive fly ash as described in claim 1, wherein the water absorption rate of the concrete doped with ultrafine reactive fly ash is between 0.9% and 1.4%. The concrete doped with ultrafine reactive fly ash as described in claim 13, wherein the water absorption rate of the concrete doped with ultrafine reactive fly ash is 0.9%. The concrete doped with ultrafine reactive fly ash as described in claim 1, wherein the at least one metal building material is steel bars, steel frames, steel plates, steel beams, pipelines or combinations thereof. An anti-corrosion method for concrete doped with ultrafine reactive fly ash, including: (A) providing a fly ash powder containing a plurality of fly ash spheres; (B) Treat the plurality of fly ash spheres with a calcination method to break the plurality of fly ash spheres to obtain an ultrafine reactive fly ash material; (C) Use the ultrafine reactive fly ash material to occupy an Mix the concrete body material in a proportion of 5% to 30% by weight; (D) prepare the concrete doped with ultrafine reactive fly ash as described in claim 1; and (E) mix the ultrafine reactive fly ash Reactive fly ash concrete encases at least one metal building material. The concrete doped with ultrafine reactive fly ash as described in claim 16, wherein the temperature range of the calcination means is between 260 and 1100 degrees Celsius. The concrete doped with ultrafine reactive fly ash as described in claim 16, wherein the at least one metal building material is steel bars, steel frames, steel plates, steel beams, pipelines or combinations thereof.