KR102561125B1 - Composition for Segment Concrete of Underground Structure - Google Patents

Abstract

The present invention relates to a technology for manufacturing continuous excavation segments of underground structures, and more specifically, to a new composition of a binder for continuous excavation segments that realizes carbon reduction by reducing the amount of cement used in the manufacture of continuous excavation segments, and to a preferred binder for such segments. This relates to highly durable concrete whose physical performance has been improved by adding an additive to prevent reinforcing bar weaving, which has the effect of suppressing chlorine ion and chloride penetration while being used.
The carbon-reducing binder composition for segments according to the present invention contains 70 to 80% by weight of three types of blast furnace slag fine powder; Type 1 ordinary Portland cement 5-15% by weight; Supercritical fluidized bed boiler fly ash 5-15% by weight; It is characterized by being composed of 10 to 20% by weight of natural anhydrous gypsum.
The concrete composition for segments according to the present invention is characterized in that 0.1 to 5 parts by weight of an additive for preventing corrosion of reinforcing bars is mixed with respect to 100 parts by weight of binder for segments in the concrete mixing, where the additive for preventing corrosion of reinforcing bars is hydrotalcite. It consists of 5 to 20 parts by weight of triethanolamine and 10 to 40 parts by weight of sodium nitrate per 100 parts by weight.

Description

Carbon-reducing, high-durability concrete for continuous excavation segments of underground structures {Composition for Segment Concrete of Underground Structure}

The present invention relates to a technology for manufacturing continuous excavation segments for underground structures. More specifically, in the production of continuous excavation segments for use in continuous excavation tunnel construction, etc., a portion of the cement is used to produce supercritical fluidized bed boiler ash, three types of blast furnace slag fine powder, and natural anhydrous. A new composition of the binder for continuous excavation segments that realizes carbon reduction by reducing the amount of cement used by replacing it with gypsum, etc., and the addition of an additive for preventing reinforcing bar non-weaving that exerts the effect of suppressing chlorine ion and chloride penetration while using this binder for segments appropriately. It is about highly durable concrete with improved physical performance.

As underground space development becomes more active, the construction of concrete underground structures is also increasing. The TBM method is a construction method for underground structures such as tunnels. The TBM (Tunnel Boring Machine) method is a method of digging a tunnel by rotating the cutterhead on the front of the excavator and assembling pre-fabricated tunnel wall segments. The TBM method excavates with a circular cross-section, so unlike conventional construction that involves repeated drilling and blasting, it is characterized by mechanically stable vibration-free, non-blasting, and mechanized excavation. Recently, a continuous excavation type TBM method was developed to continuously install spiral-shaped segments without stopping the TBM because the TBM excavation propulsion jack does not interfere with the segment installation work. The continuous excavation TBM method has the advantage of reducing costs by shortening the construction period as there is no interruption in excavation and also making excavation management easier.

In the continuous excavation type TBM method, segments are made of high-strength and high-durability concrete. If the segment material has high strength and high durability, the maintenance demand for the tunnel is reduced and the fundamental safety of the structure can be secured. Since concrete for segments is installed underground, the material itself must be able to respond to water leaks and cracks, and must be able to ensure safety even in disasters such as fire.

In Korea, segment concrete applied to the TBM method is produced with a target strength of 30 to 45 MPa, and high-strength reinforcing bars of SD400 to SD600 are used according to the design standards for concrete. The application of high-strength rebar increases the cross-section of concrete. The increase in the cross-section of concrete leads to an increase in the amount of concrete used, and the increase in the amount of concrete used leads to an increase in costs, so it is necessary to prepare countermeasures. As one of the countermeasures, the mixed use of admixtures such as fine blast furnace slag powder and fly ash was proposed. In particular, blast furnace slag fine powder is made by rapidly cooling molten blast furnace slag, which is produced simultaneously with pig iron in a blast furnace, and pulverizing it with water. When used as a substitute for cement, it improves fluidity, reduces the rate of hydration heat generation, suppresses temperature rise, improves long-term strength, and improves fluidity. It has effects such as improving water tightness. However, the use of blast furnace slag fine powder was limited because it caused an early decrease in strength.

Meanwhile, when a crack occurs in a concrete underground structure, groundwater leaks from the point where the crack occurred, greatly reducing the durability of the concrete. When sulfate (SO ₃ component) from groundwater penetrates into concrete, it reacts with C ₃ A in cement to form an expansive (2 to 3.5 times expanded) hydrate (Ettringite, C ₃ A·3CaSO ₄ ·32H ₂ O), damaging the concrete. It expands and destroys, reducing durability. Deterioration in the durability of concrete may lead to problems such as explosion of concrete and destruction of members in the event of a fire. In addition, when concrete loses its alkalinity or the chloride concentration reaches a critical value due to penetration and diffusion, the passivity film, which is the protective film of the reinforcing bar, is destroyed, and the reinforcing bar inside the concrete member is exposed to the corrosive environment and corrodes. When reinforcing bars corrode, not only does the cross-sectional area and mechanical performance of concrete deteriorate, but cracks occur in the concrete due to the expansion of reinforcing steel corrosion by-products. In addition, chloride not only corrodes the reinforcing bars in concrete, but also causes deterioration through chemical attack on the concrete structure itself.

KR 10-1794960 B1 KR 10-2013-0116979 A

The present invention was developed to improve the usability of blast furnace slag powder while improving the segments used in the construction of underground structures using methods such as the continuous excavation TBM method, and to reduce carbon by actively using industrial by-products instead of reducing the amount of cement used. There is a technical challenge in providing a binder composition for segments that realizes and secures physical performance, and highly durable concrete for segments that can be manufactured into segments that exhibit the effect of suppressing chlorine ion and chloride penetration while using such binders preferably.

In order to solve the above-described technical problem, the present invention includes 70 to 80% by weight of three types of blast furnace slag fine powder; Type 1 ordinary Portland cement 5-15% by weight; Supercritical fluidized bed boiler fly ash 5-15% by weight; Provided is a carbon-reducing binder composition for continuous excavation segments of underground structures, characterized in that it consists of 10 to 20% by weight of natural anhydrous gypsum.

In addition, in the present invention, in concrete mixing using a carbon-reduced binder composition for continuous excavation segments of underground structures, 0.1 to 5 parts by weight of an additive for preventing corrosion of reinforcing bars is mixed for 100 parts by weight of binder, and the additive for preventing corrosion of reinforcing bars is Hydrotal. Provides concrete for continuous excavation segments of underground structures, characterized in that it contains 5 to 20 parts by weight of triethanolamine and 10 to 40 parts by weight of sodium nitrate per 100 parts by weight of the site. Here, the additive for preventing corrosion of rebar is prepared by preparing 350 to 600 parts by weight of distilled water per 100 parts by weight of hydrotalcite, adding hydrotalcite to distilled water above 50°C, stirring while maintaining the temperature above 50°C, and adding triethanolamine. It can be manufactured by stirring while maintaining the temperature above 50℃ and then adding sodium nitrate and stirring.

According to the present invention, the following effects can be expected.

First, the concrete mix using the binder for continuous excavation segments of the present invention has the effect of suppressing chlorine ion and chloride penetration, thereby preventing corrosion of reinforcing bars within the segment and improving durability.

Second, instead of reducing the amount of cement used in the manufacture of continuous excavation segments of underground structures, a significant amount of blast furnace slag fine powder and supercritical fluidized bed boiler ash, which are industrial by-products, are used, thereby contributing to carbon reduction.

The present invention relates to a binder and concrete for continuous excavation segments for manufacturing continuous excavation segments of underground structures.

1. Binding material for segments

The binder for segments according to the present invention contains 70 to 80% by weight of three types of blast furnace slag fine powder; Type 1 ordinary Portland cement 5 to 15% by weight; Supercritical fluidized bed boiler fly ash 5-15% by weight; It is characterized by being composed of 10 to 20% by weight of natural anhydrous gypsum. By using a large amount of type 3 blast furnace slag fine powder, the amount of type 1 ordinary Portland cement was reduced and used in large amounts instead, while supercritical fluidized bed boiler fly ash and natural anhydrous gypsum were appropriately used to secure excellent physical properties for segmentation.

Type 3 blast furnace slag fine powder is made by quenching molten blast furnace slag, which is produced at the same time as pig iron in a blast furnace, with water and pulverizing it. It has a specific gravity of 2.80 to 2.90 and a fineness of 4,000 to 6,000 cm ² /g, and is the main material for a binder that replaces cement. do. In particular, the three types of blast furnace slag fine powders mainly contain CaO, SiO ₂ , and Al ₂ O ₃ , which helps in the creation of ettringite and thus improves strength, and also produces products that fix chloride ions (Friedel's salt, 3CaO· Because it easily generates Al ₂ O ₃ ·CaCl ₂ ·10H ₂ 0), it plays a major role in suppressing the penetration and diffusion of chloride ions. The three types of blast furnace slag fine powder are used in an amount of 70 to 80% by weight. If it is less than 70% by weight, the amount of cement increases relatively, leading to loss of economic feasibility, lack of carbon reduction effect, and lack of effect in resisting the penetration and diffusion of chloride ions. 80% by weight If it is exceeded, there is a risk of lack of early or long-term strength development.

Type 1 Portland cement is a basic binder and is used in an amount of 5 to 15% by weight in the binder. If it is less than 5% by weight, strength development is insufficient, and if it exceeds 15% by weight, it results in loss of economic feasibility and lack of carbon reduction effect.

Supercritical fluidized bed boiler fly ash is ash discharged from a supercritical fluidized bed boiler through the process of burning coal fuel under supercritical conditions while injecting oxygen, and contains 10-20% by weight of Fe ₂ O ₃ and 5-20% by weight of SO ₃ It has the characteristic of having a fineness of 6,000 to 9,000 ㎠/g. This supercritical fluidized bed boiler fly ash has a higher fineness than general chemical power plant fly ash, contributing to improved water tightness and early strength, and also plays a role in stimulating the reactivity of blast furnace slag fine powder. It is desirable to use 5 to 15% by weight of supercritical fluidized bed boiler fly ash in the binder. If it is less than 5% by weight, the strength improvement effect is minimal, and if it exceeds 15% by weight, there are concerns about a decrease in workability due to decreased fluidity and a decrease in strength. I'm concerned.

Natural anhydrous gypsum contributes to strength improvement by activating the hydration reaction of blast furnace slag fine powder and ordinary Portland cement, and also plays a role in controlling the setting time by preventing rapid setting of C ₃ A in ordinary Portland cement. Natural anhydrous gypsum is suitable if it has a specific gravity of 2.90 to 3.00 and a powder degree of 3,000 to 4,000 g/cm ³ . Natural anhydrous gypsum is used in the binder in an amount of 10 to 20% by weight. If it is less than 10% by weight, it has low activity and it is difficult to achieve physical performance, and if it exceeds 20% by weight, the strength improvement effect is minimal and economic feasibility is lost.

2. Concrete for segments

The segment concrete according to the present invention is a concrete mix using a segment binder, and is characterized in that 0.1 to 5 parts by weight of an additive for preventing corrosion of reinforcing bars is mixed with respect to 100 parts by weight of the binder. By incorporating additional additives to prevent corrosion of reinforcing bars, the purpose was to supplement the performance of resistance to corrosion of reinforcing bars within the segment. In particular, in the present invention, the additive for preventing corrosion of reinforcing bars includes 5 to 20 parts by weight of triethanolamine and 10 to 40 parts by weight of sodium nitrate per 100 parts by weight of hydrotalcite. These additives for preventing corrosion of reinforcing bars can be more preferably applied by preparing them in a liquid form.

Hydrotalcite, also known as anionic clay, layered double hydrate, or layered mixed metal hydroxide, is a layered composite hydroxide with a Mg ₆ Al ₂ (OH) ₁₆ CO ₃ ·4H ₂ O structure, with ion exchange ability, large surface area, and water resistance. It has the characteristics of insolubility and solubility. When hydrotalcite with these characteristics is applied to slag-based cement, it helps create ettringite by maintaining an alkaline environment during the concrete curing process due to the pH of 10 or higher, thereby contributing to strength improvement. Hydrotalcite also plays a role in delaying corrosion of rebar by fixing chloride ions. Hydrotalcite particles containing NO ^2- ions quickly capture chlorides (Cl ^- , SO ₄ ^2-, etc.), preventing chloride ions from penetrating into the rebar inside the concrete, and at the same time releasing NO ^2- ions into the concrete. By doing so, a passive film is formed on the reinforcing bars, thereby preventing corrosion of the reinforcing bars. Furthermore, hydrotalcite improves the water tightness of concrete by acting as a filler that fills the voids between cement and aggregate, and improving water tightness also improves the waterproof performance of concrete.

Triethanolamine is a material for improving early strength and fluidity, and is used in an amount of 5 to 20 parts by weight per 100 parts by weight of hydrotalcite. If it is less than 5 parts by weight, the effect of improving strength is minimal, and if it exceeds 20 parts by weight, it actually inhibits fluidity.

Sodium nitrate promotes the cement hydration reaction by increasing the pH of Na+ ions and at the same time acts as a filler to ensure even mixing of the concrete composition. In addition, sodium nitrate (NaNO ₃ ) contributes to ensuring usability at low temperatures by lowering the condensation temperature of the mixed water as NO ₃ ^- ions. Sodium nitrate is used in an amount of 10 to 40 parts by weight per 100 parts by weight of hydrotalcite. If it is less than 10 parts by weight, the effect of promoting the hydration reaction is minimal, and if it exceeds 40 parts by weight, there are concerns about reduced fluidity and loss of economic feasibility.

When considering dispersibility, solubility, etc., liquid additives for preventing corrosion of reinforcing bars are preferably manufactured with a solid content of 25% by weight or less while maintaining a temperature condition of 50°C or higher. Specifically, first prepare 100 parts by weight of hydrotalcite powder, 5 to 20 parts by weight of triethanolamine, 10 to 40 parts by weight of sodium nitrate, and 350 to 600 parts by weight of distilled water of 50°C or higher. Next, hydrotalcite powder is added to distilled water above 50℃ and stirred for about 2 hours at a speed of 200-250rpm while maintaining the temperature condition above 50℃ using a stirring device. It can then be prepared by adding liquid triethanolamine and stirring for more than 30 minutes while maintaining a temperature condition of 50°C or higher, and finally adding sodium nitrate (purity 99%) to dissolve it and stirring for an additional 2 hours.

Hereinafter, the present invention will be examined in detail based on manufacturing examples and test examples. However, the following manufacturing examples and test examples are only for illustrating the present invention, and the scope of the present invention is not limited thereto.

[Manufacturing example] Manufacture of additives for preventing corrosion of rebar

1. Preparation of hydrotalcite

Hydrotalcite was prepared by the nominal method. First, the molar ratio of divalent and trivalent cations is 2:1, 1 mol Mg(NO ₃ ) ₂ ·6H ₂ O (179.5 g) of divalent cation and 0.5 mol Al(NO ₃ ) ₃ ·9H ₂ O of trivalent cation. (131.3g) The reagent was dissolved in 700ml of distilled water and stirred at a speed of 250-300rpm to react for more than 30 minutes. As the reaction progressed, a white precipitate was formed and the pH of the solution lowered. As a pH adjusting solution, 1 mol (40 g) of NaOH solution was titrated over 1 to 2 hours to maintain the pH at 10 to 11. To ensure good crystallinity of the precipitate, it was aged with stirring at a temperature of 60°C for 24 hours. After crystallization was completed, the precipitate was separated through filtering and washed several times with distilled water to remove remaining sodium. The finally formed white precipitate was dried at 100°C for 12 hours and then sieved through a 100㎛ sieve, thereby producing Mg and Al-based hydrotalcite powder with the characteristics shown in [Table 1] below.

Characteristics of hydrotalcite Ingredients
(weight%) Al ₂ O ₃ content (%) MgO content (%) etc Sum 10-20 30-50 10-20 100 characteristic Specific gravity (g/cm ³ ) pH form color particle size 2.10±0.05 10.0±0.5 powder type White 200-300nm

2. Preparation of additives

For 100 parts by weight of the prepared Mg and Al-based hydrotalcite powder, 10 parts by weight of triethanolamine, 30 parts by weight of sodium nitrate, and 520 parts by weight of distilled water above 50°C were prepared, and prepared as a liquid additive. First, hydrotalcite powder was added to distilled water above 50°C and stirred using a stirring device at a speed of 200-250rpm for 2 hours, while maintaining the temperature condition above 50°C. Afterwards, liquid triethanolamine was added and stirring was performed for more than 30 minutes while maintaining a temperature condition of 50°C or higher. Finally, sodium nitrate (purity 99%) was added, dissolved, and stirred for an additional 2 hours. As a result, a liquid rebar corrosion prevention additive with a solid content of 25% by weight was prepared.

[Test Example 1] Characteristics of segment concrete according to the type of binder

1. Test specimen preparation

After mixing concrete under the conditions shown in [Table 2] below, the test specimen was molded and cured. Curing was carried out in the following way: 2 hours of air-dry curing, 6 hours of hot water curing, then 7 days of underwater curing, and then 21 days of constant temperature and humidity curing. Comparative Example 1 is a mix using cement and three types of blast furnace slag fine powder as a binder, and Comparative Example 2 is a mix using a binder in which a part of the three types of blast furnace slag fine powder in Comparative Example 1 was replaced with general fly ash, which is used for conventional segments. It is a blend using a binder, and Examples 1 and 2 are a blend using a binder for segments according to the present invention.

division W/B(%) S/a(%) Binder (kg/m ³ )
Unit Weight
aggregate
(kg/ ^m3 )
Ad.(%)
PC OPC FA CFBC GGBS C.S. Sum S A Comparative Example 1 32.3 44.5 329 - 141 - 470 770 970 3.70 Comparative Example 2 42.5 329 47 - 94 - 470 727 986 Example 1 42.5 47 - 47 329 47 470 730 988 Example 2 42.5 47 - 23.5 352.5 47 470 733 994 1) OPC: Type 1 Ordinary Portland Cement
2) FA: Type 1 fly ash
3) CFBC: Supercritical fluidized bed fly ash
4) GGBS: 3 types of blast furnace slag fine powder
5) CS: Natural anhydrous gypsum

2. Concrete properties

Slump (KS F 2402), air volume (KS F 2421), compressive strength (KS F 2405), and chlorine ion penetration resistance (KS F 2711) were measured for the test specimen. In addition, the chloride diffusion coefficient was calculated (NT BUILD 492, Chloride Migration Coefficient from Non-Steady-State Migration Experiments (Nordtest 1999)). The results are shown in [Table 3] below.

concrete properties division Slump
(mm) air
(%) compressive strength
(MPa) Chlorine ion penetration resistance (C) Chloride diffusion coefficient
(x10 ^-12 , m ² /s) 3d 7d 28d 28d 56d 28d Comparative Example 1 75 3.9 37.9 43.7 53.4 4912 3877 5.01 Comparative Example 2 65 4.0 35.8 43.9 57.1 4216 3322 6.12 Example 1 70 3.9 38.8 48.5 62.1 3022 2112 4.83 Example 2 75 4.0 37.1 50.9 63.3 2613 1890 4.44

As shown in [Table 3] above, rather than Comparative Example 2 using a conventional binder for segments, according to the present invention, general fly ash (FA) was replaced with supercritical fluidized bed fly ash (CFBC), and a part of OPC was used in three types of blast furnace. In Examples 1 and 2, which were mixed by substituting slag fine powder (GGBS) and natural anhydrous gypsum (CS), it was confirmed that the slump and air volume were increased, and in addition, the supercritical fluidized bed fly ash was reduced compared to Example 1 and three types of blast furnace slag fine powder were used. More advantageous results are confirmed in Example 2 in which is increased. It was confirmed that the compressive strength, chlorine ion penetration resistance, and chloride diffusion coefficient were also significantly improved in Examples 1 and 2 compared to Comparative Example 1.2. According to these results, the binder according to the present invention can be advantageously used as a binder for segments.

[Test Example 2] Characteristics of segment concrete according to the type of additive

1. Test specimen preparation

Concrete was mixed under the conditions shown in [Table 3] below, and a test specimen was manufactured through the same process as Test Example 1. Comparative Examples 3 to 5 and Examples 3 and 4 were mixed with the same binder as Example 2 with different types of additives. Comparative Example 3 is a formulation using only sodium nitrate as an additive, Comparative Example 4 is a formulation using additional triethanolamine to Comparative Example 3, Comparative Example 5 is a formulation using only hydrotalcite as an additive, and Comparative Example 6 and Examples 3 and 4 are formulations in which hydrotalcite was added to Comparative Example 4. In this formulation, Comparative Examples 3 to 6 used the additive components by mixing them with water and liquefying them, Example 3 used the additives of the production example, and Example 4 used the additive components in powder or liquid form as is. .

concrete mix division W/B
(%) S/a
(%) Unit Weight(kg/m ³ ) Ad (wt% compared to Bidner) Binder aggregate S.N. TEAs HDT PC Comparative Example 3 32.3 42.5 470
(OPC:47, CFBC: 23.5, GGBS: 352.5, CS:47)
S: 773
G: 994 0.3 - - 3.70 Comparative Example 4 0.3 0.1 - Comparative Example 5 - - 1.0 Comparative Example 6 0.3 0.1 0.5 Example 3 0.3 0.1 1.0 Example 4 0.3 0.1 1.0 1) SN: Sodium nitrate
2) TEA: Triethanolamine
3) HDT: hydrotalcite

2. Concrete properties

In the same manner as [Test Example 1], the slump, compressive strength, and chlorine ion penetration resistance of the test specimen were measured, and the chloride diffusion coefficient was calculated. The results are shown in [Table 5] below.

concrete properties division Slump
(mm) air
(%) compressive strength
(MPa) Chlorine ion penetration resistance (C) Chloride diffusion coefficient
(x10 ^-12 , m ² /s) 3d 7d 28d 28d 56d 28d Comparative Example 3 70 4.3 37.9 51.1 64.7 2,543 1,788 4.67 Comparative Example 4 80 4.2 36.6 50.2 65.9 2,617 1,793 4.59 Comparative Example 5 70 4.1 34.9 48.7 61.8 2,417 1,423 2.79 Comparative Example 6 70 4.2 36.0 51.3 64.1 2,393 1,359 2.54 Example 3 80 4.4 37.9 52.9 66.1 1,822 923 1.98 Example 4 85 4.2 35.3 49.1 63.0 2,072 1,178 2.27

As shown in [Table 5] above, Comparative Example 3 in which only sodium nitrate (SN) was mixed with the binder according to the present invention, and Comparative Example 4 in which triethanolamine (TEA) was additionally mixed in addition to sodium nitrate (SN). Compared to Example 2 previously examined in [Test Example 1], it showed an increase in air volume, an improvement in mid- to long-term compressive strength, a slight increase in chlorine ion penetration resistance, and a slight decrease in chloride diffusion coefficient. Comparative Example 5, which was mixed with hydrotalcite (HDT) alone, showed an increase in chlorine ion penetration resistance and chloride diffusion coefficient compared to Example 2, but showed a decrease in strength. Comparative Example 6, which mixed a small amount of hydrotalcite (HDT) in addition to sodium nitrate (SN) and triethanolamine (TEA), showed a strength improvement effect, but the chloride diffusion coefficient was lower than that of Comparative Example 5.

Example 3 is a mixture prepared and mixed according to the manufacturing example by further increasing the amount of hydrotalcite (HDT) mixed in Comparative Example 6. Compared to Comparative Example 6, slump and air volume increased, compressive strength improved, and chlorine ions were added. It showed a significant improvement in penetration resistance and chloride diffusion coefficient. Example 4 is a formulation in which sodium nitrate (SN), triethanolamine (TEA), and hydrotalcite (HDT), which are components of additives, were mixed as raw materials in powder or liquid form. Although it showed an improved effect compared to the comparative examples, it showed a lower effect than Example 3. According to these results, the additive prepared as in the preparation example shows a beneficial effect in preventing corrosion of reinforcing bars and can be advantageously used as an additive for continuous excavation segments.

Claims (3)

delete For 100 parts by weight of binder, 0.1 to 5 parts by weight of additive for preventing corrosion of reinforcing bars is mixed and mixed.
The binder is 70 to 80% by weight of three types of blast furnace slag fine powder; Type 1 ordinary Portland cement 5-15% by weight; Supercritical fluidized bed boiler fly ash 5-15% by weight; It is a carbon-reducing binder composed of 10 to 20% by weight of natural anhydrous gypsum;
The additive for preventing corrosion of reinforcing bars is a highly durable concrete for continuous excavation segments of underground structures, characterized in that it contains 100 parts by weight of hydrotalcite, 5 to 20 parts by weight of triethanolamine, and 10 to 40 parts by weight of sodium nitrate. In paragraph 2,
The additive for preventing corrosion of rebar,
After preparing 350 to 600 parts by weight of distilled water for 100 parts by weight of hydrotalcite, add hydrotalcite to distilled water above 50℃, stir while maintaining the temperature above 50℃, and add triethanolamine while maintaining the temperature above 50℃. Highly durable concrete for continuous excavation segments of underground structures, characterized in that it is manufactured into a liquid state by adding and stirring sodium nitrate after stirring.