KR101953105B1 - Underwater non-segregation cement concrete composition and construction method for expanding sectional area of water flow in sewage box - Google Patents

Abstract

The present invention relates to an underwater inseparable cement concrete composition used for expanding and constructing a water flow cross section of a sewage box, which has excellent strength, durability, contamination resistance, chloride resistance, acid resistance, adhesion, water tightness, etc.; and a method for expanding and constructing a water flow cross section of a sewage box using the composition. The underwater inseparable cement concrete composition of the present invention comprises 5 to 75 wt% of a modified binder, 5 to 65 wt% of fine aggregates, 5 to 75 wt% of coarse aggregates, and 0.1 to 15 wt% of water.

Description

UNDERWATER NON-SEGREGATION CEMENT CONCRETE COMPOSITION AND CONSTRUCTION METHOD FOR EXPANDING SECTIONAL AREA OF WATER FLOW IN SEWAGE BOX}

The present invention relates to an underwater non-separable cement concrete composition used in the sewage box passage surface expansion construction, and to a sewage box passage surface expansion construction method using the same, in order to ensure the water supply capacity of the sewage box, more specifically to the concrete in the water Even if it is poured, the pouring material does not disperse in water, expresses high viscosity while showing high fluidity, and the separability of the material separated by self-weight difference is suppressed, which makes it possible to form a constant hardened structure in water. Underwater disintegration cement concrete composition used for the expansion of sewage box through-surface to reduce the cost and shorten the air required for large-scale construction such as full iron or new construction by making full use of the structure It is about a method.

When concrete cracks occur in concrete structures due to deterioration, the compressive strength of concrete and tensile strength of reinforcing bars are gradually decreased, and concrete exposed through cracks is neutralized and corrosion of reinforcing bars occurs. If the corrosion of the reinforcing bar becomes more severe, the concrete structure may eventually collapse. Therefore, when the concrete structure is deteriorated and cracks occur, it is necessary to repair the deteriorated portion as soon as possible.

On the other hand, the recent increase in rainfall due to extreme weather causes frequent flooding, and the approach to upward revision of rainfall intensity frequency is rapidly progressing. Rapid and effective improvement measures are urgently needed to solve technical or cost problems.

In addition, rainfall has increased in recent years and the number of probable years has increased, resulting in increased rainfall intensity (sewer culverts have increased from 10 to 30 years, but are reviewed for more than 50 years). And the rapid coefficient is increasing the runoff coefficient.

In addition, if the existing sewage applause lacks the water supply capacity, the pipes of the starting point and the end point are fixed, and the existing sewage culverts are removed after securing the water supply capacity in the corresponding section. However, the existing construction method does not secure a working space and the air is increased in the process of complete demolition and construction.

Therefore, when the existing sewage box is removed and a new cross-sectional area is extended in the horizontal direction to secure the cross-sectional area, the earthwork is increased in size and high costs are caused by the installation of the temporary facility and the removal and construction of the structure. In addition, the city center has a lot of obstacles around the sewage box, making it difficult to secure space and work space for the establishment of sewage culverts. In addition, the sewage pipes connected to the existing sewage box are required to be re-constructed into the side of the sewage box to be re-introduced, resulting in high costs. In addition, due to the large-scale excavation in the city, there is a problem that causes a lot of indirect costs caused by traffic inconvenience.

On the other hand, in order to expand the cross section of the sewage box in which the groundwater is present, water disintegration is required in which the constituent raw materials of the concrete composition are not separated. In order to disintegrate in the water, required laborability that can be compacted by its own fluidity and viscosity and material separation resistance to prevent the material from being scattered are required. In the case of general cement mortar, a thickener is required for underwater disintegration having high fluidity, viscosity, and material separation resistance, compared to conventional concrete having disintegration in water, and stable cement concrete production using the same is required.

Republic of Korea Patent Registration No. 10-1720037 (registered March 21, 2017) Republic of Korea Patent Registration No. 10-1609697 (registered March 31, 2016)

The technical problem to be achieved by the present invention is that even when cement concrete is poured in water, the material is not dispersed in the water, and high viscosity is exhibited while exhibiting high fluidity, so that the separability of the material separated by the difference in weight is suppressed. Among them is to provide an underwater inseparable cement concrete composition that can form a constant cured structure.

Another technical problem to be solved by the present invention is to remove the lower slab without removing the sewage culverts and install an extended sewage box where the existing sewage box is removed, thereby eliminating the need for large-scale construction such as front maintenance or new construction. It is intended to provide a method of constructing a sewage box for cross section expansion to maximize water supply capacity.

The present invention provides a water-disintegrated cement concrete composition containing 5 to 75% by weight of modified binder, 5 to 65% by weight of fine aggregate, 5 to 75% by weight of coarse aggregate, and 0.1 to 15% by weight of water.

The modified binder is 30 to 85% by weight of crude steel portland cement, 5 to 40% by weight of blast furnace slag, 1 to 40% by weight of tricalcium aluminate cement, 1 to 20% by weight of anhydrous gypsum, 0.1 to 20% by weight of fine rock powder, sepiol 0.1 to 20% by weight of light, 0.01 to 10% by weight of sodium magnesium silicate 0.01 to 5% by weight of lithium oxide, 0.01 to 10% by weight of ethylene-methylmethacrylate or ethylene-methyl methacrylate copolymer, 0.01 to ethylene-vinyl alcohol copolymer 10 wt%, 0.01-10 wt% of polyamide-imide copolymer, 0.01-10 wt% of fluorinesilane, and 0.01-10 wt% of polyvinylbutylal.

The modified binder may further comprise 0.1 to 10% by weight of a high performance water reducing agent.

In addition, the modified binder may further comprise 0.01 to 10% by weight of the defoaming agent.

In addition, the modified binder may further comprise 0.01 to 10% by weight of calcium nitrite.

In addition, the modified binder may further comprise 0.01 to 10% by weight of the retardant.

In addition, the modified binder may further comprise 0.01 to 10% by weight of hydrophilic fiber.

In addition, the modified binder may further comprise 0.01 to 10% by weight of apatite hydroxide.

In addition, the modified binder may further comprise 0.01 to 10% by weight of polycarbosilane.

Aggregates used in the present invention are divided into fine aggregates and coarse aggregates, and those having a particle diameter of 5 mm or less are referred to as fine aggregates and those having a particle diameter larger than 5 mm as coarse aggregates. The fine aggregate is preferably contained 5 to 65% by weight with respect to the water-free separation cement concrete composition of the present invention, the coarse aggregate is preferably contained 5 to 75% by weight relative to the water-free separation cement concrete composition of the present invention.

In addition, according to one embodiment of the present invention, to expand the cross section of the existing sewage box in the formwork and concrete pouring method, the step of installing a reinforcement in the existing sewer box buried underground; Cutting both sides of the lower slab of the existing sewage box to a predetermined width, excavating a lower portion thereof, and placing reinforcement to the excavated portion, and then placing the water-dissociable cement concrete composition to install an earth barrier; Excavating the lower slab of the existing sewage box after the black film is installed, and then pouring rubble concrete layer after compacting rubble on the bottom of the excavated portion; After reinforcing the reinforcing bar on the side and the bottom of the excavated portion, the bottom is laid by curing the water-free separation cement concrete, the side is installed wall formwork and then the water-free separation cement concrete is poured and cured Forming an expansion sewage box; Weld each of the rebar ends exposed at the connection between the cross section of the remaining portion of the lower slab of the existing sewage box and the top of the expansion sewage box, and connect them to each other, and install the formwork at the connected site, and then remove the water-free cement concrete By pouring and curing, so that the lower side of the side of the existing sewage box and the upper side of the expansion sewage box is connected to each other; And it provides a method for expanding the sewage box through-plane expansion surface comprising the step of removing and finishing the reinforcement and formwork.

According to another embodiment of the present invention, to expand the cross section of the existing sewage box in a precast concrete (PC) method, the step of installing a reinforcement in the existing sewer box buried underground; Cutting both sides of the lower slab of the existing sewage box to a predetermined width, excavating a lower portion thereof, and placing reinforcement on the excavated portion, and then placing the water-dissociable cement concrete composition to install an earth barrier; Excavating the lower slab of the existing sewage box after installing the earthen membrane, and then pouring rubble concrete layer after compacting rubble on the bottom of the excavated portion; Forming an expanded sewage box by placing the prefabricated PC having an open shape after striking the discarded concrete layer; Weld each of the rebar ends exposed at the connection between the cross section of the remaining part of the lower slab of the existing sewage box and the top of the side of the expansion sewage box, and connect each other, and install the formwork at the connected site and then remove the cement Placing and curing concrete, such that the bottom of the side of the existing sewage box and the top of the side of the expansion sewage box are connected to each other; And it provides a method for expanding the sewage box through-plane expansion surface comprising the step of removing and finishing the reinforcement and formwork.

According to the water-disintegrated cement concrete composition of the present invention, it is excellent in strength, durability, pollution resistance, salt resistance, acid resistance, adhesion, water tightness, etc., which can prevent concrete corrosion due to chemical erosion of the structure, and thus the maintenance cost used therefor. The effect can be remarkably reduced.

In addition, by providing excellent fluidity, cohesion and material separation resistance than existing cement concrete products, it is possible to form stable concrete structures in the water.In addition, it prevents underwater contamination by excellent cohesion and protects the reinforcement of underwater structures. It can be effective.

In addition, according to the sewage box passage section expansion construction method of the present invention, without removing the existing sewage box, by removing a portion of the lower slab and extending vertically to the removed place to install the sewage box vertically the cross-sectional area to extend the water supply capacity It does not require large-scale construction such as full-scale repair or new construction, and unskilled workers can be installed quickly and economically with predetermined quality.

1 is a flow chart illustrating a process of the passage section expansion construction method of the sewage box according to an embodiment of the present invention.
Figure 2 is a schematic diagram for explaining the process of installing the reinforcing material in the existing sewage box of the cross-sectional expansion construction method of the sewage box according to an embodiment of the present invention.
Figure 3 is a schematic diagram for explaining the process of constructing the expansion box in the formwork and concrete placing method in the lower portion of the existing sewage box of the water supply section expansion construction method of the sewage box according to an embodiment of the present invention.
Figure 4 and Figure 5 is a schematic diagram for explaining the process of constructing the expansion box by the prefabricated PC method in the lower portion of the existing sewage box of the water supply section expansion construction method of the sewage box according to an embodiment of the present invention.

Hereinafter, preferred embodiments of the present invention will be described in detail. However, the following embodiments are provided to those skilled in the art to fully understand the present invention, and may be modified in various forms, and the scope of the present invention is limited to the embodiments described below. It doesn't happen.

Underwater disintegrating cement concrete composition according to a preferred embodiment of the present invention, 5 to 75% by weight of the modified binder, 5 to 65% by weight of the aggregate, 5 to 75% by weight of the coarse aggregate and 0.1 to 15% by weight of water.

The modified binder having excellent strength and durability is 30 to 85% by weight of crude steel portland cement, 5 to 40% by weight of blast furnace slag, 1 to 40% by weight of tricalcium aluminate cement, 1 to 20% by weight of dry gypsum, and natural stone powder 0.1 to 20 % By weight, 0.1 to 20% by weight of sepiolite, 0.01 to 5% by weight of lithium oxide, 0.01 to 10% by weight of ethylene-methyl methacrylate or ethylene-methyl methacrylate copolymer, 0.01 to 10% by weight of ethylene-vinyl alcohol copolymer It is preferable to contain%, 0.01-10 weight% of polyamide-imide copolymers, 0.01-10 weight% of fluorinesilane, and 0.01-10 weight% of polyvinyl butylal.

The crude steel portland cement is preferably used cement that meets the KS standards. The ordinary portland cement is preferably contained 30 to 85% by weight based on the modified binder.

The blast furnace slag is used to improve latent hydraulic properties, long-term strength development and durability. When the weight ratio of the blast furnace slag powder is increased, the early strength is lowered, but the long-term strength expression and durability are increased. The blast furnace slag is preferably contained 5 to 40% by weight based on the modified binder. When the content of the blast furnace slag exceeds 40% by weight, durability is improved, but early strength expression is lowered, and when the content of the blast furnace slag is less than 5% by weight, the effect of improving long-term strength and durability is insufficient.

The tricalcium aluminate cement is used to improve early strength, crack resistance by shrinkage, chemical resistance, in particular acid resistance. The tricalcium aluminate cement is preferably contained 1 to 40% by weight based on the modified binder. When the weight ratio of the tricalcium aluminate cement is increased, it shows a fast curing property, and when the content of the tricalcium aluminate cement is less than 1% by weight, early strength expression, crack resistance, chemical resistance and acid resistance improvement effect may be weak. When the content of the tricalcium aluminate cement is more than 40% by weight, good physical properties can be obtained due to the fast curing property, but the manufacturing cost is high, which is not economical.

The anhydrous gypsum (CaSO ₄ ) reacts with components in the cement, in particular C ₃ A (3CaO.Al ₂ O ₃ ) to initially produce ethrinzite (AFt phase, C ₃ A · 3CaSO ₄ · 32H ₂ O). The resulting ethrinzite is reduced in amount as the hydration proceeds, or a portion thereof is transferred to the mono sulfate (on AFm, C ₃ A · CaSO ₄ · 12H ₂ O). As in the present invention, when a large amount of anhydrous gypsum is added, ethrinzite is sufficiently produced from the beginning to densify the structure of the cement, thereby increasing the penetration resistance to chloride ions in the early age. In addition, in the case of general cement, the produced ethrinzite is mainly present only at the initial stage, but in the modified binder of the present invention, since a sufficient amount of gypsum is added, ethrinzite is also present in a part of the long-term age or part of ethrin Zites may be generated continuously. The ethrinzite produced in this way densely fills the voids in the concrete structure, thereby increasing the penetration resistance against chlorides even at long-term age. The anhydrous gypsum is preferably contained 1 to 20% by weight based on the modified binder. When the content of the anhydrous gypsum is less than 1% by weight, the durability improvement effect may be weak, and when the content of the anhydrous gypsum exceeds 20% by weight, the reactivity is lowered, leading to early strength expression and water resistance.

The feldspar powder has a tetragonal crystal with a high SiO ₂ content and is used to improve strength, self-healing, waterproofing, salting resistance and freeze-thawing resistance due to its high pozzolanic reactivity. The natural rock powder is preferably contained 0.1 to 20% by weight based on the modified binder. When the amount of the chalcedony powder is less than 0.1% by weight, the effect of improving self-healing, water resistance, salt resistance, and freeze-thawing resistance may be insignificant, and when the content of the feldspar powder exceeds 20% by weight, early strength expression is lowered. do.

The sepiolite serves as an adsorbent as a porous inorganic material. The sepiolite is preferably contained in an amount of 0.1 to 20% by weight based on the modified binder. Increasing the weight ratio of the sepiolite shows a viscosity improving performance, if the content of the sepiolite is less than 0.1% by weight may be a weak viscosity improving effect, when the content of the sepioolite exceeds 20% by weight It is not economical because workability is degraded and manufacturing cost is high.

The sodium magnesium silicate is used to improve the workability and hygroscopicity by adjusting the viscosity. When the weight ratio of the sodium magnesium silicate increases, the early strength is lowered, but the viscosity and hygroscopicity are improved. The sodium magnesium silicate is preferably contained in an amount of 0.01 to 10% by weight based on the modified binder. When the content of sodium magnesium silicate is less than 0.01% by weight, the workability, the hygroscopicity improvement effect may be insignificant. When the content of the sodium magnesium silicate is more than 10% by weight, the hygroscopicity is better but the viscosity is higher workability and strength Is lowered.

The lithium oxide is used to improve strength, crack resistance, water resistance and fire resistance. The lithium oxide is preferably contained in an amount of 0.01 to 5% by weight based on the modified binder. When the content of the lithium oxide is less than 0.01% by weight, the effect of improving the strength, crack resistance, water resistance and fire resistance is insufficient. When the content of the lithium oxide is more than 5% by weight, the effect of improving the performance is not great and the economy is inferior.

The ethylene-methyl methacrylate or ethylene-methyl methacrylate copolymer is used to improve strength, durability and material separation resistance. The ethylene-methyl methacrylate or ethylene-methyl methacrylate copolymer is preferably contained in an amount of 0.01 to 10% by weight based on the modified binder. When the content of the ethylene-methyl methacrylate or ethylene-methyl methacrylate copolymer is less than 0.01% by weight, the effect of improving strength, durability and material separation prevention is insufficient, and the ethylene-methyl methacrylate or ethylene-methacrylic acid When the content of the methyl copolymer exceeds 10% by weight, the performance improvement effect is obvious, but workability is lowered.

The ethylene-vinyl alcohol copolymer is used to improve material separation resistance and water resistance. The ethylene-vinyl alcohol copolymer is preferably contained in an amount of 0.01 to 10% by weight based on the modified binder. When the content of the ethylene-vinyl alcohol copolymer is less than 0.01% by weight, the effect of improving material separation resistance and water resistance is insufficient. When the content of the ethylene-vinyl alcohol copolymer is more than 10% by weight, the performance improvement effect is obvious, but the work The castle is degraded.

The polyamide-imide copolymer is used to improve strength, heat resistance, material separation resistance and water resistance. The polyamide-imide copolymer is preferably contained in an amount of 0.01 to 10% by weight based on the modified binder. When the content of the polyamide-imide copolymer is less than 0.01% by weight, the effect of improving strength, heat resistance, material separation resistance and water resistance is insufficient, and when the content of the polyamide-imide copolymer exceeds 10% by weight, performance is achieved. The improvement is obvious, but the workability and economic efficiency are deteriorated.

The fluorine silane is used to improve the strength and durability by increasing the reactivity. The fluorine silane is preferably contained in an amount of 0.01 to 10% by weight based on the modified binder. When the content of the fluorine silane is less than 0.01% by weight, the reactivity is lowered and the performance improvement effect is insufficient. When the content of the fluorine silane is more than 10% by weight, the reactivity is increased to lower workability.

The polyvinyl butyl al is used to improve strength and durability. The polyvinyl butyl al is preferably contained in an amount of 0.01 to 10% by weight based on the modified binder. When the content of the polyvinyl butyl al is less than 0.01% by weight, the effect of improving the strength and durability is insufficient, and when the content of the polyvinyl butylal exceeds 10% by weight, the performance improving effect is obvious but workability is lowered.

The modified binder may further comprise a high performance water reducing agent. The high performance water reducing agent is used to improve the strength and durability by reducing the water-cement ratio of the modified binder. The high performance water reducing agent may use a polycarboxylic acid-based, melamine-based or naphthalene-based fluidizing agent. Melamine-based or naphthalene-based sensitizers have less strength and durability improvement effects than polycarboxylic acid sensitizers, do not significantly reduce the water-cement ratio, and when mixed with performance-improving agents, foaming occurs, resulting in poor miscibility. There is this. Therefore, it is preferable to use a polycarboxylic acid type high performance water reducing agent, and it is preferable that 0.1-10 weight% is contained with respect to the said modified binder.

In addition, the modified binder may further include an antifoaming agent to increase the strength and durability by removing bubbles in the modified binder. In addition, when the antifoaming agent is added to the performance improving agent, it is possible to improve workability and pot life by giving an air entraining effect. The antifoaming agent is preferably contained in an amount of 0.01 to 10% by weight based on the modified binder. The antifoaming agent may be an alcoholic antifoaming agent, a silicone antifoaming agent, a fatty acid antifoaming agent, an oil antifoaming agent, an ester antifoaming agent, an oxyalkylene antifoaming agent, or the like. The silicone antifoaming agent includes dimethylsilicone oil, polyorganosiloxane, fluorosilicone oil and the like. The fatty acid antifoaming agent includes stearic acid, oleic acid and the like. The oil-based defoamer includes kerosene, animal and vegetable oils, castor oil and the like. The ester antifoaming agent may include solitol trioleate, glycerol monoricinoleate, and the like. Examples of the oxyalkylene antifoaming agent include polyoxyalkylene, acetylene ethers, polyoxyalkylene fatty acid esters, polyoxyalkylene alkylamines, and the like. The alcoholic antifoaming agent includes glycol and the like.

In addition, the modified binder may further include calcium nitrite. The calcium nitrite is used to prevent corrosion of reinforcing steel in the concrete. The calcium nitrite is preferably contained 0.01 to 10% by weight based on the modified binder.

In addition, the modifying binder may further include a retardant. The retardant may be used to secure workability for a certain time and delay the hardening. The retarder is preferably contained in an amount of 0.01 to 10% by weight based on the modified binder. As the retarder, generally well-known substances can be used, for example, sugars such as glucose, glucose, textine, dextran, gluconic acid, malic acid, citric acid, citric acid or salts thereof, aminocarboxylic acids Or salts thereof, phosphonic acids or derivatives thereof, polyhydric alcohols such as glycerin, and the like.

In addition, the modified binder may further include any one or a mixture of hydrophilic fibers of hydrophilic nylon fibers, polyvinyl chloride (PVC) fibers, polyethylene (PE) fibers and polypropylene (PP) fibers. The hydrophilic fiber can be used to prevent plastic cracking and to improve bending toughness. The hydrophilic fiber is preferably contained in an amount of 0.01 to 10% by weight based on the modified binder. When the content of the hydrophilic fiber is less than 0.01% by weight, the effect of preventing plastic cracking and improving the flexural toughness may be insignificant, and when the content of the hydrophilic fiber is more than 10% by weight, workability is lowered and manufacturing cost is high. Can not do it.

In addition, the modified binder may further include apatite hydroxide. The apatite hydroxide is used to improve the strength, chemical resistance, and wear resistance. The apatite hydroxide is preferably contained in an amount of 0.01 to 10% by weight based on the modified binder. Increasing the weight ratio of the apatite hydroxide shows strength, chemical resistance, and wear resistance. When the content of the apatite hydroxide is less than 0.01% by weight, the effect of improving strength, chemical resistance, and abrasion resistance may be weak, and the content of the apatite hydroxide is 10 weight. If it exceeds the percentage, the manufacturing cost increases and it is not economical.

In addition, the modified binder may further include polycarbosilane. The polycarbosilane is used to improve strength, heat resistance, wear resistance, and durability. The polycarbosilane is preferably contained in an amount of 0.01 to 10% by weight based on the modified binder. Increasing the weight ratio of the polycarbosilane indicates strength, heat resistance, wear resistance, and durability. When the content of the polycarbosilane is less than 0.01% by weight, strength, heat resistance, wear resistance, and durability improvement effects may be weak, and the polycarbosilane If the content of more than 10% by weight, the manufacturing cost is high, it is not economical.

Aggregates used in the present invention are divided into fine aggregates and coarse aggregates, and those having a particle diameter of 5 mm or less are referred to as fine aggregates and those having a particle diameter larger than 5 mm as coarse aggregates. The fine aggregate is preferably contained 5 to 65% by weight with respect to the water-free separation cement concrete composition of the present invention, the coarse aggregate is preferably contained 5 to 75% by weight relative to the water-free separation cement concrete composition of the present invention.

Hereinafter, a method for producing an underwater undissolved cement concrete composition according to a preferred embodiment of the present invention.

In the water-disintegrated cement concrete composition according to a preferred embodiment of the present invention, 5 to 75% by weight of the modified binder, 5 to 65% by weight of the aggregate and 5 to 75% by weight of the coarse aggregate in a forced mixer, water 0.1 It can be prepared by adding 15 wt% by mixing for a predetermined time (for example, 1 to 10 minutes) with a forced mixer or a continuous mixer.

In the following, the sewage box through the cross-sectional expansion construction method using the above-mentioned underwater undissolved cement concrete composition is presented.

1 is a flow chart illustrating a process of the construction method for extending the cross section of the sewage box according to an embodiment of the present invention, Figure 2 is a view for explaining a process of installing a reinforcement in the existing sewage box of the construction method illustrated in FIG. 3 is a schematic view illustrating a process of constructing an expansion box in a formwork and concrete pouring method under the existing sewage box among the construction methods illustrated in FIG. 1, and FIGS. 4 and 5 are illustrated in FIG. 1. It is a schematic diagram for explaining a process of constructing an expansion box by a prefabricated PC method under the existing sewage box of the construction method.

According to the method for expanding the cross-section of the sewage box of the sewage box according to the embodiment of the present invention illustrated in FIGS. 1 to 5, the entire sewage box is not dismantled, but the side wall and the upper slab of the existing sewage box are left unchanged. Extend the cross section below the slab. To this end, first, the lower slab of the existing sewage box is crushed and the lower part is excavated. Then, on the excavated part, an expansion sewer box is formed by (1) formwork and concrete pouring or (2) prefabricated PC seating. After that, the bottom of the existing sewage box and the bottom of the extended sewage box are connected and finished.

Specifically, as illustrated in FIGS. 1 and 2, first, a step 101 of installing a reinforcement in an existing sewage box buried in the ground is performed. The reason for installing the reinforcement in this step 101 is, according to the present invention, while removing the lower slab 20a and the lower sidewall 20b and the upper slab 20c of the existing sewage box 20 intact. Since the expansion construction should proceed in progress, in order to maintain a stable shape of the existing sewage box 20 having a generally rectangular cross section as illustrated in (a) of FIG. The reinforcement may be made of a horizontal reinforcement 22, a lateral reinforcement 24, and a vertical reinforcement 26, for example, may be made of a rigid material in the form of a column, such as H beam. First, as illustrated in FIG. 2B, the horizontal reinforcement 22 is parallel in the longitudinal direction (ie, the length direction of the sewage box) at both ends of the lower slab 20a in the existing sewage box 20. Can be installed. Then, as illustrated in (c) of Figure 2, it is possible to install the lateral reinforcement 24 to support both horizontal reinforcing material 22 portions to support each other at intervals of, for example, 1 ~ 2m. Finally, as illustrated in (d) of FIG. 2, the vertical reinforcing material 26 is in a state where the lower end of the vertical reinforcing material 26 is in contact with the portion where the horizontal reinforcing material 22 and the horizontal reinforcing material 24 overlap the side wall 20b. ) Can be installed in such a way that the top of the existing contact with the upper slab (20c) of the existing sewage box (20). Due to the structure of the reinforcing materials (22, 24, 26), the substantially rectangular cross-sectional shape of the existing sewage box 20 can be stably maintained during expansion.

Once the reinforcement installation is complete, step 103 of FIG. 1 proceeds, as illustrated in FIGS. 3A, 4A, and 5A, of the existing sewage box 20. After crushing the concrete of the portion between the two horizontal stiffeners 22 in the lower slab (22a), excavate the lower portion, and reinforce the reinforcement to the excavated portions (31, 41, 51) after the water-insoluble cement concrete The composition is poured to install the retainers 32, 42, and 52.

As a result, as illustrated in (a) of FIG. 3, (a) of FIG. 4, and (a) of FIG. 5, an expansion space B is formed below the existing space A of the existing sewage box 20. do.

By forming a concrete layer on the inner surface of the expansion space (B) formed in this way, expansion sewage boxes 30, 40, as illustrated in (d), (d) and (d) of FIG. 50). This may be done in any of the formwork and pouring method 105 and the prefabricated PC method 1006, as illustrated in FIG.

The construction in the formwork and pouring method 105 is illustrated in steps 107 and 109 of FIG. 1 and FIG. 3B. First, in step 107, the rubble is compacted 33 at the bottom of the excavated portion 31, and the discarded concrete layer 34 is poured thereon. After the poured concrete is cured, in step 109, after reinforcing the reinforcing bars on the side and the bottom of the excavated portion 31, the bottom is cured by pouring in-water disintegrated cement concrete according to the present invention, After installing the wall formwork on the side can be poured and cured under-water disintegrated cement concrete according to the present invention can form an expanded sewer box (35).

형태 또는 상부가 열려 있는 대체로 반원형 단면을 가진 둥근 U자 형상이지만, 도시된 예로만 한정될 필요는 없고, 다양한 단면 형상이 가능하다는 것은 해당 기술 분야의 통상의 지식을 가진 자에게 자명할 것이다.On the other hand, the construction in the prefabricated PC system 106 is illustrated in step 108 of FIG. 1, (b) and (b) of FIG. In step 108, after forming the rubble compaction and discarded concrete layers, the prefabricated PCs are seated on the inner surfaces of the excavated portions 41 and 51 to form the expanded sewage boxes 43 and 53. In this case, prefabricated concrete (PC) refers to the concrete body made by manufacturing in advance in the factory. The assembled PC in the present invention corresponds to the shape of the inner surface of the excavated portions 41 and 51 and has an open top. Specifically, in the example shown in FIG. 4, the prefabricated PC is an angled U-shape having a generally rectangular cross section with a └┘ shape or an open top, and the prefabricated PC in the example shown in FIG.

Although rounded U-shape having a generally semi-circular cross-section that is open in shape or top, it need not be limited to the illustrated example, and it will be apparent to those skilled in the art that various cross-sectional shapes are possible.

Once the expansion sewage boxes 35, 43, 53 are constructed, respectively, as illustrated in step 111 of FIG. 1 and (c) of FIG. 3, (c) of FIG. 4 and (c) of FIG. The lower end of the existing sewage box 20 and the upper end of the expanded sewage box 35, 43, 53 form a connection portion 36, 45, 55 adjacent to each other. At this time, the rebar exposed to the end of the remaining portion of the lower slab 20a at the bottom of the side wall slab of the existing sewage box 20, and the rebar exposed to the top of the side wall of the expansion sewage box (35, 43, 53) Are welded together. Then, after installing the formwork at the site where the reinforcing bar is placed and cured under water undetached cement concrete according to the present invention. As a result, the lower sides of the existing sewage box 20 and the upper sides of the expanded sewage boxes 35, 43, and 53 may be smoothly formed to connect the connection parts 36, 45, and 55 to each other with a concrete material.

Finally, as shown in step 113 of FIG. 1, the reinforcement was installed in the existing space (A) of the existing sewage box 20, and the expanded sewage boxes (30, 40) completed thereunder are formed. Remove and finish the formwork installed to As a result, as illustrated in (d) of FIG. 3, (d) of FIG. 4, and (d) of FIG. 5, the expansion space B extending below the existing space A of the existing sewage box 20 is formed. Can be formed.

Hereinafter, the embodiments of the water-insoluble cement concrete composition according to the present invention will be described in more detail, and the present invention is not limited by the following examples.

<Example 1>

20 wt% of the modified binder, 30 wt% of the fine aggregate, and 40 wt% of the coarse aggregate were premixed in a forced mixer, and then mixed with a forced mixer for 10 minutes by adding 10 wt% of water to prepare a cement-free cement concrete composition in water. .

At this time, the modified binder is 35% by weight of crude steel Portland cement, 15% by weight of blast furnace slag, 15% by weight of tricalcium aluminate cement, 10% by weight of anhydrous gypsum, 5% by weight of sedimentary rock powder, 5% by weight of sepiolite, sodium magnesium silicate 5% by weight, 1% by weight lithium oxide, 1% by weight ethylene-methyl methacrylate or ethylene-methyl methacrylate copolymer, 1% by weight ethylene vinyl alcohol copolymer, 1% by weight polyamide-imide copolymer, fluorine 1% by weight of silane, 1% by weight of polyvinylbutylal, 1% by weight of calcium nitrite, 0.5% by weight of high performance water reducing agent, 0.5% by weight of antifoaming agent, 0.5% by weight of retardant, 0.5% by weight of hydrophilic fiber, 0.5% by weight of apatite hydroxide and polycarbosilane 0.5 weight% was used in mixture. The high performance reducer used a polycarboxylic acid-based high performance reducer. Citric acid was used as the retardant. The hydrophilic fibers used nylon fibers. The antifoaming agent was a silicone antifoaming agent.

<Example 2>

20 wt% of the modified binder, 30 wt% of the fine aggregate, and 40 wt% of the coarse aggregate were premixed in a forced mixer, and then mixed with a forced mixer for 10 minutes by adding 10 wt% of water to prepare a cement-free cement concrete composition in water. .

At this time, the modified binder is 32.5% by weight of crude steel Portland cement, 15% by weight of blast furnace slag, 15% by weight of tricalcium aluminate cement, 10% by weight of anhydrous gypsum, 5% by weight of sedimentary rock powder, 5% by weight of sepiolite, sodium magnesium silicate 5% by weight, lithium oxide 1%, ethylene-methyl methacrylate or ethylene-methyl methacrylate copolymer 1.5% by weight, ethylene vinyl alcohol copolymer 1.5% by weight, polyamide-imide copolymer 1.5% by weight, fluorine 1 wt% silane, 1 wt% polyvinylbutylal, 2 wt% calcium nitrite, 0.5 wt% high performance water reducing agent, 0.5 wt% antifoaming agent, 0.5 wt% retardant, 0.5 wt% hydrophilic fiber, 0.5 wt% apatite hydroxide and polycarbosilane 0.5 weight% was used in mixture. The high performance reducer used a polycarboxylic acid-based high performance reducer. Citric acid was used as the retardant. The hydrophilic fibers used nylon fibers. The antifoaming agent was a silicone antifoaming agent.

<Example 3>

20 wt% of the modified binder, 30 wt% of the fine aggregate, and 40 wt% of the coarse aggregate were premixed in a forced mixer, and then mixed with a forced mixer for 10 minutes by adding 10 wt% of water to prepare a cement-free cement concrete composition in water. .

At this time, the modified binder is 30% by weight of crude steel Portland cement, 15% by weight of blast furnace slag, 15% by weight of tricalcium aluminate cement, 10% by weight of anhydrous gypsum, 5% by weight of sedimentary rock powder, 5% by weight of sepiolite, sodium magnesium silicate 5 wt%, 1 wt% lithium oxide, 2 wt% ethylene-methylmethacrylate or ethylene-methyl methacrylate copolymer, 2 wt% ethylene vinyl alcohol copolymer, 2 wt% polyamide-imide copolymer, fluorine 2 wt% silane, 1.5 wt% polyvinylbutylal, 1.5 wt% calcium nitrite, 0.5 wt% high performance water reducing agent, 0.5 wt% antifoaming agent, 0.5 wt% retardant, 0.5 wt% hydrophilic fiber, 0.5 wt% apatite hydroxide and polycarbosilane 0.5 weight% was used in mixture. The high performance reducer used a polycarboxylic acid-based high performance reducer. Citric acid was used as the retardant. The hydrophilic fibers used nylon fibers. The antifoaming agent was a silicone antifoaming agent.

In order to more easily understand the characteristics of Examples 1 to 3 above, comparative examples that can be compared with the embodiments of the present invention are presented, and Comparative Examples 1 and 2, which will be described later, are commonly used cements. A mortar composition and a polymer cement mortar composition are presented.

Comparative Example 1

Usually, 20% by weight of Portland cement, 30% by weight of fine aggregate, 40% by weight of coarse aggregate, and 10% by weight of water were stirred with a forced mixer to prepare a normal cement mortar composition.

The following test examples show the experimental results comparing the characteristics of the examples according to the invention with the characteristics of Comparative Examples 1 and 2 to more easily understand the characteristics of Examples 1 to 3 according to the present invention .

<Test Example 1>

According to the method defined in KS L 5220, the flow test (flowability at the time of non-strike) was measured for the water-indeterminate cement concrete composition prepared in Examples 1 to 3 and the cement concrete composition prepared in Comparative Example 1.

Material separation was judged by stirring concrete by hand, and underwater specimen was prepared by free fall after installing 10cm mold under water. The results are shown in Table 1.

division Example 1 Example 2 Example 3 Comparative Example 1 Flow (mm) 188 195 202 115 Material separation none none none Occur

As shown in Table 1, it was found that the flowability at the time of non-strike of the water-disintegrated cement concrete composition prepared according to Examples 1 to 3 showed very high flowability than Comparative Example 1 and showed excellent fluidity. In addition, in Comparative Example 1, material separation occurred, but in Examples 1 to 3, no material separation occurred.

<Test Example 2>

In order to compare the physical properties of the water-disintegrated cement concrete composition prepared according to Examples 1 to 3 and the cement concrete composition prepared in Comparative Example 1, the water prepared according to Examples 1 to 3 described above The non-separated cement concrete composition and the cement mortar composition prepared in Comparative Example 1 were subjected to a compressive strength test by KS F 2476 (Test Method of Polymer Cement Mortar), and the results are shown in Table 2 below. In addition, the flexural strength test was performed by KS F 2476, and the results are shown in Table 3 below. In addition, the adhesive strength was measured by KS F 2476 and the results are shown in Table 4 below.

division Example 1 Example 2 Example 3 Comparative Example 1 Compressive strength
(MPa) 3 days 32.5 33.5 35.3 28.5 28 days 50.8 53.5 56.0 45.0 3 days underwater 30.5 31.5 33.6 27.1 28 days underwater 49.3 51.2 54.2 46.0

division Example 1 Example 2 Example 3 Comparative Example 1 Flexural strength
(MPa) 3 days 4.8 5.1 5.5 2.2 28 days 6.0 6.3 6.8 4.8 3 days underwater 4.5 4.9 5.3 1.6 28 days underwater 5.8 6.1 6.5 5.0

division Example 1 Example 2 Example 3 Comparative Example 1 Adhesive strength
(MPa) 3 days 1.5 1.6 1.8 0.6 28 days 1.9 2.0 2.1 1.3 3 days underwater 1.3 1.5 1.7 0.8 28 days underwater 1.8 2.0 2.1 1.4

As shown in Table 2 to Table 4, the compression, bending and adhesive strength of the water-indeterminate cement concrete composition prepared according to Examples 1 to 3 was significantly higher than the cement concrete composition prepared according to Comparative Example 1. .

It was confirmed that the water-insoluble cement concrete composition prepared according to Examples 1 to 3 was much superior in strength compared to the cement concrete composition prepared in Comparative Example 1.

<Test Example 3>

The rate of change in length was measured by KS F 2476 for the water-indeterminate cement concrete composition prepared according to Examples 1 to 3 and the cement concrete composition prepared according to Comparative Example 1, and the results are shown in Table 5 below.

division Example 1 Example 2 Example 3 Comparative Example 1 Length change rate (%) 0.05 0.03 0.02 0.12

As shown in Table 5 above, it is confirmed that the water-disintegrated cement concrete composition prepared according to Examples 1 to 3 has a reduction effect in shrinkage as the length change rate is reduced compared to the cement concrete composition prepared according to Comparative Example 1. Could.

<Test Example 4>

The measurement results of the water absorption rate according to the method specified in KS F 2476 for the water-indeterminate cement concrete composition prepared according to Examples 1 to 3 and the cement concrete composition prepared according to Comparative Example 1 are shown in Table 6 below. . If the absorption rate is high, if the impurities or water penetrates into the concrete, the porosity increases in the concrete, causing a problem of damage to the structure.

division Example 1 Example 2 Example 3 Comparative Example 1 Absorption rate (%) 0.6 0.5 0.3 2.0

As shown in Table 6 above, the water-indeterminate cement concrete composition prepared according to Examples 1 to 3 had a lower absorption rate than the cement concrete composition prepared according to Comparative Example 1.

<Test Example 5>

In-water intact cement concrete compositions prepared according to Examples 1 to 3 and cement concrete compositions prepared according to Comparative Example 1 were tested by KS F 4042, and the results are shown in Table 7 below.

division Example 1 Example 2 Example 3 Comparative Example 1 Chloride Ion Penetration Resistance (coulombs) 800 710 650 1650

As shown in Table 7 above, the water-indeterminate cement concrete composition prepared according to Examples 1 to 3 has less chloride ion penetration depth than that of the cement mortar composition prepared according to Comparative Example 1, thereby providing resistance to salt damage. It was confirmed that high.

<Test Example 6>

In-water intact cement concrete compositions prepared according to Examples 1 to 3 and cement concrete compositions prepared according to Comparative Example 1 were tested by KS F 4042, and the results are shown in Table 8 below.

division Example 1 Example 2 Example 3 Comparative Example 1 Neutralization Depth (mm) 0.9 0.7 0.6 1.9

As shown in Table 8, the water-insoluble cement concrete composition prepared according to Examples 1 to 3 has a lower neutralization penetration depth than the cement concrete composition prepared according to Comparative Example 1, resulting in high resistance to neutralization. Could confirm.

<Test Example 7>

2% hydrochloric acid according to the Japanese Industrial Standards [Method for testing chemical resistance by solution deposition of concrete] was prepared from the water-insoluble cement concrete composition prepared according to Examples 1 to 3 and the cement concrete composition prepared according to Comparative Example 1. , 5% sulfuric acid and 45% aqueous solution of sodium hydroxide was immersed in the test solution for 28 days to test the chemical resistance test results are shown in Table 9 below.

division Example 1 Example 2 Example 3 Comparative Example 1 Weight change rate
(%) Hydrochloric acid -1.3 -1.0 -0.8 -5.0 Sulfuric acid -0.3 -0.2 -0.1 -2.3 Sodium hydroxide +0.3 +0.4 +0.8 -0.1

As shown in Table 9, in the water-disintegrated cement concrete composition prepared according to Examples 1 to 3 has a lower weight change rate for chemical resistance than the cement concrete composition prepared according to Comparative Example 1 It was confirmed that the resistance to high.

<Test Example 8>

The measurement results of the freeze-thaw resistance test according to the method specified in KS F 2456 of the water-indeterminate cement concrete composition prepared according to Examples 1 to 3 and the cement concrete composition prepared according to Comparative Example 1 are shown in Table 10 below. Shown in Freeze-thawing refers to the freezing and melting of water absorbed in the capillary to concrete, and repeated freeze-thawing causes fine cracks in the concrete structure, resulting in deterioration in durability. Table 10 shows the durability index of each of the Examples and Comparative Examples according to the freeze thaw resistance test.

division Example 1 Example 2 Example 3 Comparative Example 1 Durability index 91 92 93 68

As shown in Table 10 above, since the water-insoluble cement concrete composition prepared according to Examples 1 to 3 is significantly higher durability index than the cement concrete composition prepared according to Comparative Example 1, it is found that durability is improved. Can be.

As mentioned above, although preferred embodiment of this invention was described in detail, this invention is not limited to the said embodiment, A various thing by the person of ordinary skill in the art within the range of the technical idea of this invention. Modifications are possible.

Claims (10)

It is a water-free separation cement concrete composition for the expansion of sewage box
5 to 75% by weight of modified binder, 5 to 65% by weight of fine aggregate, 5 to 75% by weight of coarse aggregate, and 0.1 to 15% by weight of water,
The modified binder is 30 to 85% by weight of crude steel portland cement, 5 to 40% by weight of blast furnace slag, 1 to 40% by weight of tricalcium aluminate cement, 1 to 20% by weight of anhydrous gypsum, 0.1 to 20% by weight of fine rock powder, sepiol 0.1 to 20% by weight of light, 0.01 to 10% by weight of sodium magnesium silicate 0.01 to 5% by weight of lithium oxide, 0.01 to 10% by weight of ethylene-methylmethacrylate or ethylene-methyl methacrylate copolymer, 0.01 to 10% by weight of ethylene vinyl alcohol copolymer 10 wt%, 0.01-10 wt% of polyamide-imide copolymer, 0.01-10 wt% of fluorinesilane, 0.01-10 wt% of polyvinylbutylal, 0.1-10 wt% of high-performance water reducing agent, 0.01-10 wt% of antifoaming agent 0.01 to 10% by weight of calcium nitrite, 0.01 to 10% by weight of retardant, 0.01 to 10% by weight of hydrophilic fiber, 0.01 to 10% by weight of apatite hydroxide, and 0.01 to 10% by weight of polycarbosilane,
Flow (mm) measured according to the method specified in KS L 5220 is 188 ~ 202 mm,
The compressive strength (MPa) carried out by KS F 2476 (Test Method for Polymer Cement Mortar) is 32.5 ~ 35.3 in 3 days, 50.8 ~ 56.0 in 28 days, 30.5 ~ 33.6 in 3 days, 49.3 ~ 54.2 in 28 days, Flexural strength (MPa) is 4.8 ~ 5.5 in 3 days, 6.0-6.8 in 28 days, 3-4.5-5.3 days in water, 5.8-6.5 in 28 days, and adhesive strength (MPa) is 1.5-1.8 in 3 days, 28 days in air 1.9 to 2.1, 3 days to 1.3 ~ 1.7, 28 days to 1.8 ~ 2.1, the length change rate (%) is 0.02 ~ 0.05, the water absorption rate (%) is 0.3 ~ 0.6,
Chloride ion penetration resistance (coulombs) by KS F 4042 is 650 ~ 800, neutralization depth (mm) is 0.6 ~ 0.9,
According to the Japanese Industrial Standards [Method for testing chemical resistance by solution deposition of concrete], 2% hydrochloric acid, 5% sulfuric acid, and 45% sodium hydroxide aqueous solution was dipped into the test solution for 28 days. (%) Is -1.3 to -0.8 for hydrochloric acid, -0.3 to -0.1 for sulfuric acid, +0.3 to +0.8 for sodium hydroxide,
According to the method specified in KS F 2456, the endurance index of the freeze-thaw resistance test was 91 to 93.
Underwater fireless cement concrete composition, characterized in that.
delete delete delete delete delete delete delete As a method for expanding the sewage box passage surface for expanding the water passage cross section of an existing sewage box by using a water-insoluble cement concrete composition according to claim 1 in a formwork and concrete pouring method,
Installing reinforcement in existing sewer boxes buried underground;
Cutting both lower portions of the existing sewage box to a predetermined width, excavating a lower portion thereof, and placing reinforcement on the excavated portion, and then placing the underwater unseparated cement concrete composition to install an earth barrier;
Excavating the lower slab of the existing sewage box after installing the earthen membrane, and then pouring rubble concrete layer after compacting rubble on the bottom of the excavated portion;
After reinforcing the reinforcing bar on the side and the bottom of the excavated portion, the bottom is laid by curing the water-free separation cement concrete, the side is installed wall formwork and then the water-free separation cement concrete is poured and cured Forming an expansion sewage box;
Weld each of the rebar ends exposed at the connection between the cross section of the remaining part of the lower slab of the existing sewage box and the upper end of the expansion sewage box, and connect each other, and install the formwork at the connected area, and then the water-free cement concrete By pouring and curing, so that the lower side of the side of the existing sewage box and the upper side of the expansion sewer box is connected to each other; And
Removing and finishing the reinforcement and formwork
Sewage box passage surface expansion construction method comprising a.
As a method of expanding the sewage box passage surface for expanding the water passage section of an existing sewage box using a precast concrete (PC) method using the water-incommunicable cement concrete composition according to claim 1,
Installing reinforcement in existing sewer boxes buried underground;
Cutting both sides of the lower slab of the existing sewage box to a predetermined width, excavating a lower portion thereof, and placing reinforcement to the excavated portion, and then placing the water-dissociable cement concrete composition to install an earth barrier;
Excavating the lower slab of the existing sewage box after installing the earthen membrane, and then pouring rubble concrete layer after compacting rubble on the bottom of the excavated portion;
After placing the discarded concrete layer, seating a prefabricated PC having an open top shape to form an expanded sewage box;
Weld each of the rebar ends exposed at the connection between the cross section of the remaining part of the lower slab of the existing sewage box and the top of the side of the expansion sewage box, and connect each other, and install the formwork at the connected site and then remove the cement Placing and curing concrete, such that the bottom of the side of the existing sewage box and the top of the side of the expansion sewage box are connected to each other; And
Removing and finishing the reinforcement and formwork
Sewage box passage surface expansion construction method comprising a.

Images