JP2007177567A - Mortar spraying method in construction, repair method for damaged portion in concrete structure, and concrete structural body - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a mortar spraying method in construction, a repair method for damaged portions in a concrete structure, and a concrete structure which is repaired by the methods by removing concrete portions where cracks or fissures occurred due to salt damage or aggregate reaction, by using a high pressure water spraying method capable of suppressing any reaction of aggregate in concrete structures without creating any reoccurrence of the cracks or fissures due to aggregate reaction in the repaired portions. <P>SOLUTION: In the mortar spraying method, a mixture 35 (dry mortar) made by mixing polymer cement and aggregate together is fed under pressure from dry mortar supplying equipment 32 to a mortar spraying nozzle 31 through a hose 34 by compressed air 33. Mortar 37 is made by mixing dry mortar, water and lithium nitrite together in the mortar spraying nozzle 31 and then the mortar 37 is sprayed to predetermined places of the concrete structural body. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a mortar spraying method suitable for repairing the occurrence of cracks or cracks due to corrosion of iron due to salt damage of a concrete structure or the like, or expansion of the surface of the aggregate due to aggregate reaction, or suppression of aggregate reaction, concrete structure The present invention relates to a method for repairing a damaged part of a body and a repaired concrete structure.

Many concrete materials such as reinforcing bars and steel frames are embedded in concrete structures such as road piers and bridges in order to increase the strength. When a corrosive solution containing chloride penetrates into such a concrete structure, rust occurs in the iron material, the surface of the iron material expands, and many cracks and cracks occur in the concrete in the vicinity of the iron material. Has a problem of deterioration (decrease). Especially in roads in snowy areas, many chlorides such as calcium chloride are used as a snow-melting agent (snow-melting agent), and the snow-melting water contains a lot of chloride, and the snow-melting water penetrates into concrete structures such as bridge piers, chloride ion Cl ^- acts on the passive film iron embedded in the concrete structure, it is experiencing many problems that rust is generated in the iron material destroying unmoving kinetics film.

  In addition, if the alkali component and moisture are present in the concrete under appropriate conditions, the silica component of the silica aggregate in the concrete reacts with the alkali and water (aggregate reaction), and the reaction product accumulates and grows on the surface of the aggregate. There is also a problem that the concrete surface is cracked and cracked and the concrete strength deteriorates (decreases).

  Conventionally, cracks and cracks have occurred in concrete due to salt damage and aggregate reaction, and when the strength is reduced, the concrete where the cracks and cracks have occurred is removed by spraying with high-pressure water or the like (chips), The removed part was repaired by filling with mortar. However, if cracks or cracks occur due to salt damage or aggregate reaction again after repair, such repair must be performed again, and in some cases, such repair must be performed at predetermined intervals. There is also a problem.

  The present invention has been made in view of the above points, and when cracks or cracks occur due to salt damage or aggregate reaction, the cracked or cracked concrete is removed by spraying with high pressure water or the like, and this removal is performed. A mortar spraying method that can prevent a crack or crack from occurring due to salt damage or an aggregate reaction, and can suppress the aggregate reaction of a concrete structure even if the mortar is filled and repaired. An object of the present invention is to provide a method for repairing a damaged portion of a structure and a repaired concrete structure.

  In order to solve the above-mentioned problem, the invention according to claim 1 sprays a mortar formed by mixing polymer cement, aggregate, water and a lithium nitrite solution onto a predetermined portion of a concrete structure through a mortar spray nozzle. It is characterized by.

  The invention according to claim 2 is the mortar spraying method according to claim 1, wherein the mortar spraying from the mortar spray nozzle is performed by compressing the mixture of the polymer cement and the aggregate with compressed air through a hose. The mortar spray nozzle is pumped, and the water and lithium nitrite solution are mixed into the mixture immediately before the mortar spray nozzle or in the mortar spray nozzle to form a mortar, which is sprayed from the mortar spray nozzle. .

  The invention according to claim 3 is the mortar spraying method according to claim 1, wherein the mortar spraying from the mortar spray nozzle is a mixture of the polymer cement, aggregate, water, and lithium nitrite solution. The mortar is transferred to the mortar spray nozzle through a hose, and compressed air is supplied to the mortar spray nozzle for spraying.

  The invention according to claim 4 removes the damaged portion of the concrete where cracks and cracks have occurred due to the corrosion of the iron structure of the concrete structure embedded with the reinforcing iron material by removing the iron material, and adds mortar to the concrete removing portion. A method for repairing a damaged part of a concrete structure by filling and repairing the damaged part, wherein a mortar formed by mixing polymer cement, aggregate, water, and a lithium nitrite solution is added to the concrete removing part excluding the iron material. It is characterized by being filled by spraying through a mortar spray nozzle.

  According to a fifth aspect of the present invention, in the method for repairing a damaged portion of the concrete structure according to the fourth aspect, the mortar spraying from the mortar spraying nozzle is performed by passing the mixture of the polymer cement and the aggregate through a hose. The mortar spray nozzle is compressed by compressed air, and the mixture is mixed with the water and lithium nitrite solution immediately before the mortar spray nozzle or in the mortar spray nozzle, and sprayed from the mortar spray nozzle. It is characterized by.

  The invention according to claim 6 is the method for repairing a damaged portion of the concrete structure according to claim 4, wherein the mortar spraying from the mortar spray nozzle is performed by using the polymer cement, the aggregate, water, and the lithium nitrite solution. The mixed mortar is transferred to the mortar spray nozzle, and compressed air is supplied to the mortar spray nozzle for spraying.

  The invention according to claim 7 is the method for repairing a damaged portion of a concrete structure according to claim 5 or 6, wherein after removing the damaged portion of the concrete except the reinforcing bar, a rust preventive material is applied to the reinforcing bar. A rust prevention treatment layer is provided.

  The invention according to claim 8 is the method for repairing a damaged portion of a concrete structure according to claim 5 or 6, wherein after removing the damaged portion of the concrete except for the reinforcing bars, the mortar is formed on the surface of the concrete removing portion. It is characterized in that an adhesive layer coated with an adhesive material that improves the adhesion of is provided.

  The invention according to claim 9 is a concrete structure in which a damaged portion of concrete in which cracks or cracks are generated by an aggregate reaction of a concrete structure is removed, and the concrete removed portion is filled with mortar to repair the damaged portion. A method for repairing a damaged part of a body, wherein the concrete removing part is filled with mortar formed by mixing polymer cement, aggregate, water and a lithium nitrite solution through a mortar spray nozzle.

    The invention according to claim 10 is the method for repairing a damaged portion of a concrete structure according to claim 9, wherein the mortar spraying from the mortar spray nozzle is performed by passing the mixture of the polymer cement and the aggregate through a hose. The mortar spray nozzle is compressed by compressed air, and the mixture is mixed with the water and lithium nitrite solution immediately before the mortar spray nozzle or in the mortar spray nozzle, and sprayed from the mortar spray nozzle. It is characterized by.

  The invention according to claim 11 is the method for repairing a damaged portion of a concrete structure according to claim 9, wherein the mortar spraying from the mortar spray nozzle is performed by using the polymer cement, the aggregate, water, and the lithium nitrite solution. The mixed mortar is transferred to the mortar spray nozzle, and compressed air is supplied to the mortar spray nozzle for spraying.

  The invention according to claim 12 removes a damaged part of concrete in which cracks or cracks have occurred due to iron corrosion for reinforcing a concrete structure and / or an aggregate reaction, and a polymer cement, an aggregate, It is characterized by being repaired by filling a mortar made by mixing water and lithium nitrite solution.

According to the first aspect of the invention, since the mortar mixed with the lithium nitrite solution is sprayed to a predetermined portion of the concrete structure through the mortar spray nozzle, the mortar is bonded (attached) to the concrete structure with a strong binding force. In addition, even if water containing chloride penetrates into this place, the chloride ion (Cl ⁻ ) of the chloride is neutralized by the nitrite ion (NO ₂ ⁻ ) of lithium nitrite (LiNO ₂ ), and As will be described in detail later, the passive film destroyed by chlorine ions (Cl ⁻ ) on the surface of the iron material embedded in the concrete is regenerated by lithium nitrite (LiNO ₂ ) to prevent the generation of rust. Further, since lithium ions (Li) of lithium nitrite (LiNO ₂ ) in the mortar react with the silica component of the silica aggregate to form an insoluble reaction layer (Li ₂ O × Sio ₂ ) on the surface, The material reaction is suppressed. Therefore, it is possible to prevent cracks and cracks from occurring in the concrete due to salt damage and aggregate reaction, thereby reducing the strength.

  According to the invention described in claim 2, the mixture of polymer cement and aggregate is pumped to the mortar spray nozzle by compressed air through a hose, and the mixture is formed immediately before the mortar spray nozzle or in the mortar spray nozzle. By mixing water and lithium nitrite solution into mortar, and so-called dry mortar spraying from the mortar spray nozzle, the polymer cement and aggregate mixture (dry mortar) is pumped over a long distance as described later. The mortar spraying method range can be set widely, and mortar can be sprayed at a high speed, so that a mortar layer having high density and high bond strength of concrete can be formed.

  According to invention of Claim 3, the mortar which mixes a polymer cement, an aggregate, water, and a lithium nitrite solution is transferred to a mortar blowing nozzle via a hose, and compressed air is supplied to this mortar blowing nozzle By so-called wet mortar spraying, the mortar pumping distance is shorter and the spraying speed is lower than the dry type as described later, so the mortar spraying method range is narrow, and the bonding force between mortar and concrete However, it is easy to make the ratio of water and polymer cement constant, and the amount of rebound of the mortar is small when the mortar is sprayed, and the waste of the mortar is reduced.

According to invention of Claim 4, the mortar which mixes a polymer cement, aggregate, water, and a lithium nitrite solution in the part which removed the damaged part of the concrete which the crack and the crack generate | occur | produced was passed through the mortar spraying nozzle. Since the mortar is bonded (attached) to the concrete structure with a strong bonding force, chlorine ions (Cl ⁻ ) are liquified with lithium nitrite (LiNO) even if water containing chloride penetrates into this place. ₂₎ nitrite ions (NO ₂ ^-) is neutralized with, further chloride ions iron surface being embedded in the concrete (Cl ^-) disrupted lithium nitrite of passive film in mortar (LiNO ₂ ) To prevent rusting.

  According to the invention of claim 5, the mixture of polymer cement and aggregate is pumped to the mortar spray nozzle by compressed air through a hose, and the mixture is formed immediately before the mortar spray nozzle or in the mortar spray nozzle. By mixing water and lithium nitrite solution into mortar, and so-called dry mortar spraying from the mortar spray nozzle, the polymer cement and aggregate mixture (dry mortar) is pumped over a long distance as described later. In addition, it is possible to repair the damaged parts of concrete structures existing in a wide range, and mortar is sprayed at high speed, so that a mortar layer with high density and high bond strength of concrete can be formed.

  According to the sixth aspect of the present invention, a mortar formed by mixing polymer cement, aggregate, water, and a lithium nitrite solution is transferred to the mortar spray nozzle, and compressed air is supplied to the mortar spray nozzle for blowing. By applying so-called wet mortar spraying, the mortar pumping distance is shorter and the spraying speed is lower than the dry type as described later, so the repair range of the concrete structure is narrow, and the bonding force between mortar and concrete is Although it becomes weak, it is easy to make the ratio of water and polymer cement constant, and the amount of rebound of the mortar is small when the mortar is sprayed, and the waste of the mortar is reduced.

  According to the invention described in claim 7, since the rust prevention treatment layer is provided on the reinforcing bar, the rust prevention of the iron material is further improved and salt damage can be prevented.

  According to the eighth aspect of the present invention, since the adhering material layer is provided on the surface of the concrete removing portion, it is possible to form a mortar layer having a greater binding force with the concrete.

According to the ninth aspect of the present invention, the damaged part of the concrete cracked or cracked due to the aggregate reaction of the concrete structure is removed, and the polymer cement, the aggregate, water, and the lithium nitrite solution are added to the concrete removed part. Since the mortar is mixed by spraying through a mortar spray nozzle, the lithium ion (Li) of lithium nitrite (LiNO ₂ ) in the mortar reacts with the silica component of the silica aggregate and is insoluble on the surface. Since the layer (Li ₂ O × Sio ₂ ) is formed, the aggregate reaction is suppressed.

  According to the invention of claim 10, the mixture of polymer cement and aggregate is pumped to the mortar spray nozzle by compressed air through a hose, and the mixture is formed immediately before the mortar spray nozzle or in the mortar spray nozzle. Mixing water and lithium nitrite solution into a mortar, and so-called dry mortar spraying from the mortar spray nozzle allows polymer cement and aggregate mixture (dry mortar) to be pumped over long distances and exists widely. It is possible to repair the damaged part of the concrete structure due to the aggregate reaction, and to spray mortar at a high speed, so that a mortar layer with high density and high bond strength of concrete can be formed.

  According to invention of Claim 11, the mortar formed by mixing polymer cement, aggregate, water and lithium nitrite solution is transferred to a mortar spray nozzle, and compressed air is supplied and sprayed to the mortar spray nozzle. By so-called wet mortar spraying, the mortar pumping distance is shorter and the spraying speed is lower than the dry type, so the repair range of the concrete structure by the aggregate reaction is narrow, and the bonding force between mortar and concrete is weak However, it is easy to make the ratio of water and polymer cement constant, and the amount of rebound of the mortar is small when the mortar is sprayed, and the waste of the mortar is reduced.

  According to the twelfth aspect of the present invention, since the concrete removal portion is filled with mortar formed by mixing polymer cement, aggregate, water, and lithium nitrite solution, salt damage and aggregate reaction are caused in the repair portion. Thus, it is possible to provide a concrete structure that is free from cracks and cracks.

  Embodiments of the present invention will be described below with reference to the drawings. In this embodiment, snowmelt water containing a snow-smelting agent chloride melted by a snow-smelting agent (snow-melting agent) such as calcium chloride permeates the piers of roads in snowy areas and penetrates the reinforcing bars embedded in the piers. An example of repairing when rust occurs in the iron material and cracks or cracks occur in the surrounding concrete will be described, but the present invention is not limited to this, and water containing chloride in the concrete structure Widely used for repairing aggregate reaction damage that inhibits salt reaction, cracks and cracks in concrete caused by rusting in embedded steel material that penetrates and buried, and cracks and cracks in concrete due to aggregate reaction, and suppression of aggregate reaction it can.

FIG. 1 is a diagram showing a configuration example of a top portion of a bridge pier laid in a snowfall area, and an end portion of a bridge 11 is mounted and supported on the top portion of a bridge pier 10. When there is snow on the upper surface (road surface) of the bridge 11, a snow-melting agent such as magnesium chloride or calcium chloride is applied to melt the snow. Most of the snowmelt water 12 flows through the gap between the ends of the bridge 11 and flows down through the surface of the pier 10, but a part of the snowmelt water 12 penetrates into the concrete of the pier 10. The snowmelt water 12 contains a snow-removing agent chloride, and the chloride film (Cl ⁻ ) of the chloride destroys the passive film on the surface of the iron material 13, thereby generating rust on the iron material 13. When rust is generated in the iron material 13 and the surface of the iron material 13 expands due to the rust, the surrounding concrete material is pressed and cracks and cracks are generated in the concrete. When the cracks and cracks are generated, the snowmelt water penetrates through the cracks and cracks, the rust of the iron material 13 further proceeds, more cracks and cracks are generated in the concrete, and the strength of the concrete is reduced.

  FIG. 2A is a diagram showing a part of the pier 10 near the iron material 13. As illustrated, when the rust of the iron material 13 proceeds, many cracks and cracks 15 are generated in the concrete 14 around the iron material 13. Since the concrete strength of the portion where the cracks and cracks 15 are generated deteriorates, it is necessary to remove this portion and fill the removed portion with mortar using the mortar spraying method according to the present invention to reinforce and repair. The following repair method will be described. First, as shown in FIG. 2 (b), the damaged concrete portion 16 where cracks and cracks 15 have occurred is crushed and removed (clawed) by electric and air picks, water jets, etc., and shown in FIG. 2 (c). Thus, the concrete removal part 17 is formed in the peripheral part of the iron material 13.

Next, rust on the surface of the iron material 13 is removed by sandblasting or the like. Subsequently, dirt and harmful substances on the surface of the concrete removing portion 17 (base material concrete surface) are removed by sand blasting and water jet to expose a sound foundation of the concrete 14. In this state, as shown to Fig.3 (a), a rust prevention material is apply | coated to the surface of the iron material 13 which removed rust, and the rust prevention process layer 18 is formed. Here, as the rust preventive material, for example, a mixture of calcium silicate, silicon dioxide, and sodium benzoate in a predetermined ratio is used. As shown in FIG. 3 (b) in a state where a rust prevention layer 18 is formed on the surface of the iron material 13, as will be described in detail later in the concrete removing portion 17, polymer cement, aggregate (sand), water, and nitrous acid. Mortar formed by kneading a lithium (LiNO ₂ ) solution is sprayed through a nozzle to form a mortar packed layer 19. Subsequently, as shown in FIG. 3C, a finishing mortar layer 20 is formed on the mortar filling layer 19, and a surface treatment layer (for example, an acrylic coating layer) 21 is formed on the finishing mortar layer 20. .

Further, as shown in FIG. 2 (c), a concrete removing portion 17 is formed in the peripheral portion of the iron material 13, the rust on the surface of the iron material 13 is dropped, and a rust preventive material is applied to the surface of the iron material 13 to prevent the rust-preventing treatment layer 18 Form the
The dirt and harmful substances on the surface of the concrete removing portion 17 are removed to expose a sound foundation of the concrete 14. Next, as shown in FIG. 4A, an adhesive material 22 is formed by applying an adhesive material to improve the adhesion of the mortar to the surface of the concrete removing portion 17. Next, as shown in FIG. 4 (b), mortar formed by kneading polymer cement, aggregate (sand), water and a solution of lithium nitrite (LiNO ₂ ) is sprayed to the concrete removing portion 17 through a nozzle. A mortar filling layer 19 is formed. Subsequently, as shown in FIG. 4C, a finished mortar layer 20 is formed on the mortar filling layer 19, and a surface treatment layer (for example, an acrylic coating layer) 21 is formed on the mortar layer 20. In addition, as the adhering material for forming the adhering material layer 22, a material obtained by mixing calcium silicate, calcium formate, butyl acrylate-styrene and silica sand in a predetermined ratio is used.

The mortar obtained by removing the cracked and cracked concrete damaged portion 16 as described above and spraying the concrete removed portion 17 with polymer cement, aggregate, water, and lithium nitrite solution through the mortar spray nozzle is used. Since the filling layer 19 is formed, the mortar filling layer 19 is bonded (attached) to the surface of the concrete removing portion 17 (base material concrete surface) with a strong bonding force. And when snowmelt water containing chloride permeates into the mortar packed layer 19, chloride ions (Cl ⁻ ) of the chloride destroy the passive film on the surface of the iron material 13, but it exists in the mortar packed layer 19. Since the passive film destroyed by the action of nitrite ions (NO ₂ ⁻ ) of lithium nitrite (LiNO ₂ ) is re-formed, rust generation on the surface of the iron material 13 is prevented. FIG. 5 is a diagram showing the mechanism of destruction and regeneration of the passive film. As shown in FIG. 5 (a), when chloride permeates into the concrete 14 in which the iron material 13 is embedded, its chloride ion (Cl ⁻ ), oxygen ion (O ²⁻ ), water (H ₂ O). As a result, the passive film on the surface of the iron material 13 is destroyed as Fe (OH) ₂ , but as shown in FIG. 5B, in the mortar packed layer 19, lithium nitrite (LiNO ₂ ) present in the mortar. A passive film destroyed by the following reaction is re-formed by the action of nitrite ions (NO ₂ ⁻ ).
Fe ²⁺ + 2OH ⁻ + 2NO ⁻ → 2NO + Fe ₂ O ₃ + H ₂ O

The silica component of the silica aggregate 23 in the concrete 14 reacts in the presence of predetermined alkali components (K ⁺ , Na ⁺ , OH ⁻ ) and water (H ₂ O) as shown in FIG. 6 (a). (Aggregate reaction), a formed gel (Na ₂ O.nSiO ₂ .mH ₂ O) layer 24 is formed on the surface of the silica aggregate 23, and the concrete 14 is pressed by the growth and expansion of the generated gel layer 24, Cracks and cracks 25 are generated on the surface. In contrast, in the mortar packed layer 19 containing lithium nitrite (LiNO ₂ ), as shown in FIG. 6B, lithium ions (Li ⁺ ) react with the silica component of the silica aggregate 23 and become insoluble on the surface. Since the reaction product (Li ₂ O × Sio ₂ ) layer 26 is formed, the aggregate reaction is suppressed. It is possible to prevent cracks and cracks from occurring in the concrete 14 due to the aggregate reaction resulting from the strength being lowered.

  There are dry and wet mortar spraying methods. As shown in FIG. 7, the dry mortar spraying method includes a mortar spray nozzle 31, and the mortar spray nozzle 31 and the dry mortar supply device 32 are connected by a hose 34. Compressed air 33 is supplied to the dry mortar supply device 32, and a predetermined amount of polymer cement / aggregate mixture (dry mortar) 35 is cut out from the dry mortar supply device and put into the hose 34. Compressed air 33 is supplied into the hose 34, and the mixture of polymer cement and aggregate is uniformly mixed with the compressed air 33 while being compressed by the compressed air through the hose 34, and a mortar spray nozzle. 31. A mixed liquid 36 of water and a lithium nitrite solution is supplied to the mortar spray nozzle 31, and the mixed liquid 36 is mixed into a mixture of polymer cement and aggregate uniformly mixed with compressed air in the mortar spray nozzle 31, The mortar 37 is sprayed from the mortar spray nozzle 31 to the concrete removing portion 17 (see FIGS. 2, 3, and 4) of the pier 10, and the concrete removing portion 17 is filled with the mortar 37 (forms the mortar filling layer 19). . The mixing and kneading of the mixture 36 of compressed air, polymer cement, aggregate, water and lithium nitrite solution may be performed immediately before the mortar spray nozzle 31.

  As shown in FIG. 8, the wet mortar spraying method includes a mortar spray nozzle 41, and the mortar spray nozzle 41 and the mortar supply device 42 are connected by a hose 43. A mortar 44 obtained by mixing and kneading polymer cement, aggregate, water, and lithium nitrite solution is accommodated in the mortar supply device 42, and the mortar 44 is pumped to the mortar spray nozzle 41 through the hose 43. By supplying the compressed air 45 to the mortar spray nozzle 41, the mortar 44 is sprayed from the mortar spray nozzle 41 to the concrete removing portion 17 of the bridge pier 10, and the concrete removing portion 17 (see FIGS. 2, 3, and 4). Is filled with mortar 44 (forms mortar filling layer 19).

The dry mortar spraying method and the wet mortar spraying method have the following merits and demerits, respectively.
(Dry type)
-Since adjustment of the water | moisture content of the mortar 37 is performed with the quantity of the water inject | poured into the mortar spray nozzle 31, it depends on the operator's skill.
-The amount of mortar 37 that rebounds (the mortar that rebounds from the concrete surface) 37 is greater than wet (10-20%), and the amount of mortar 37 that is wasted increases.
The polymer cement / aggregate mixture 35 in the hose 34 is dry and can be reused. Further, the inside of the hose 34 need not be cleaned every day.
-Since the transfer distance of the polymer cement / aggregate mixture 35, that is, the length of the hose 34 can be increased (maximum distance horizontal 200m, height direction 150m), the mortar spray nozzle 31 can be moved in a wide range. , Mortar spraying construction range becomes large.
-Mortar spraying speed can be made high speed (200 km / h), and the sprayed mortar adheres to the concrete surface with high density and strong bonding force.

(Wet)
The mortar is obtained by mixing polymer cement, aggregate, water, and lithium nitrite solution in the mortar feeder 42, so that the ratio of water to polymer cement can be made constant, and it can be obtained batchwise so There is little outbreak.
-The amount of mortar 44 that rebounds (the mortar that bounces off the concrete surface) 44 is less than the dry type (2-5%), and the amount of mortar 44 that is wasted is small.
-The pumping speed of the mortar 44 is constant.
-When trouble occurs, it is necessary to clean the inside of the hose 43 or the like (if left untreated, the mortar 44 is cured and clogged inside the hose 43 or the like).
-Since the mortar pumping distance, that is, the length of the hose 43 cannot be made longer than the dry type (maximum 60 m), the moving range of the mortar spray nozzle 41 is narrow, and the mortar spraying construction range cannot be widened.
-Since the mortar spraying speed cannot be increased as compared with the dry type (100 km / h), the bonding force of the sprayed mortar is smaller than that of the dry type.

  FIG. 9 is a diagram showing a schematic configuration example of a dry mortar spraying apparatus. As shown in FIG. 9, the dry mortar spraying apparatus includes a silo 51, a sprayer 52, and a compressor 53. A mixture (dry mortar) of polymer cement and aggregate stored in the silo 51 is supplied to the sprayer 52 through the supply pipe 54. The spraying machine 52 includes a hopper 55 and a cutting machine 56, and the mixture of polymer cement and aggregate supplied through the supply pipe 54 is accommodated in the hopper 55, and is cut from the hopper 55 by a cutting machine 56 by a predetermined amount. It is taken out and put into the hose 43. Compressed air 33 is supplied into the hose 43 from the compressor 53, and the polymer cement / aggregate mixture 35 is mixed with the compressed air 33 while the hose 43 is transferred a predetermined distance (60 m or more). It is mixed uniformly and reaches the mortar spray nozzle 31. A mixed liquid 36 of water and lithium nitrite solution is supplied to the mortar spray nozzle 31 through a hose 57, and the polymer cement, the aggregate, the compressed air 33 and the mixed liquid 36 are mixed and sprayed to the pier 10 as a mortar 37. . In addition, in order to prevent dust from scattering to the mixture of polymer cement and aggregate (dry mortar), the liquid mixture 36 is supplied through the supply pipe 54 in an amount that prevents dust from scattering.

  FIG. 10 is a diagram showing a schematic configuration example of a wet mortar spraying apparatus. As shown in FIG. 10, the wet mortar spraying apparatus includes a silo 61, a mortar feeder 62, and a compressor 63. The mortar feeder 62 includes a hopper 64, a mortar stirring extruder 65, and a motor 67 that drives the mortar stirring extruder 65. Mortar obtained by mixing polymer cement, aggregate, and water (including lithium nitrite solution) in silo 61 is supplied to hopper 64 by, for example, dispensing mechanism 66, and mortar stirring extruder 65 is driven by motor 67. The mortar is pumped through the hose 43 to the mortar spray nozzle 41. The compressed air 45 is supplied from the compressor 63 to the mortar spray nozzle 41 through the hose 68, and the mortar 44 is sprayed from the mortar spray nozzle 41 to the pier 10.

  As the polymer cement used in the dry mortar spraying method, for example, a mixture of calcium silicate, calcium formate, butyl acrylate-styrene, and silica sand in a predetermined ratio is used. Examples of the polymer cement used in the wet mortar spraying method include calcium silicate, 2,2-dimethyl-1,3-propanediol, styrene acrylate, silicon dioxide, calcium formate, calcium oxide, and calcium fluoride. A mixture mixed at a predetermined ratio is used.

An example of a method for calculating the amount of lithium nitrite used in the mortar by the dry mortar spraying apparatus will be described below.
・ Molar ratio (nitrite ion / chloride ion) is calculated from the following formula.
Molar ratio _{^{(NO 2 - / Cl -)}} = (NO 2 - amount / NO ₂ ^- molecular weight) / (Cl ^- amount / Cl ^- molecular weight)
= (NO ₂ ^- amount /46.0)/(Cl ^- amount /35.5)
· NO ₂ ^- amount calculation formula NO ₂ ^- weight = molar ratio × (Cl ^- amount / Cl ^- molecular weight) × NO ₂ ^- molecular weight
= Molar ratio × (Cl ^- amount /35.5)×46.0

Here, Cl in Concrete ^- amount: 1.0 kg / m ^3, the molar ratio of 1: 5, lithium nitrite solution: If the case of the concentration of 20 wt% density, calculation of the amount of lithium nitrite (LiNO ₂₎ An example is as follows.
NO ₂ ^- weight = molar ratio × (Cl ^- amount / Cl ^- molecular weight) × NO ₂ ^- molecular weight
= 1.5 × (1.0 kg / m ³ /35.5)×46.0
≒ 1.944

Lithium nitrite amount (kg / m ³ ) = 1.944 × (LiNO ₂ molecular weight / NO ₂ molecular weight)
= 1.944 × (52.9 / 46.0)
≒ 2.236

Amount of lithium nitrite aqueous solution (kg / m ³ ) = 2.236 / 0.2
= 11.18
If the weight per 1 m ^{3 of} spray mortar is 2200 kg, the amount of cement is 25%, and the ratio of water to cement is 40%, the amount of water used is 220 kg, and the amount of lithium nitrite aqueous solution mixed is 11.18 / 220 = 5 .1%

In order to suppress the aggregate reaction of the concrete structure, a mixture of polymer cement, aggregate, water, and lithium nitrite is formed on the surface of the concrete structure 71 by the mortar spraying method of claim 1 as shown in FIG. A mortar layer 72 is formed. As a result, lithium nitrite (LiNO ₂ ) in the mortar layer 72 penetrates into the concrete structure 71, and lithium ions (Li ⁺ ) react with the silica component of the silica aggregate 23 and are insoluble on the surface. The (Li ₂ O × Sio ₂ ) layer 26 is formed and the aggregate reaction is suppressed. That is, when there is a possibility that an aggregate reaction may occur, suppression of the aggregate reaction can be expected by forming a mortar layer 72 containing a lithium nitrite solution on the surface of the concrete structure 71.

In addition, as shown in FIG. 12, a concrete removal portion 74 is formed by removing a damaged concrete portion having cracks or cracks on the surface due to an aggregate reaction, and the concrete removal portion 74 has a polymer cement, an aggregate, water, a sublimation. When mortar filled with lithium nitrate is sprayed through a mortar spray nozzle to form the mortar filling portion 75, the mortar filling portion 75 is insoluble on the surface of the silica aggregate 23 as in FIG. 6B. The product (Li ₂ O × Sio ₂ ) layer 26 is formed and the aggregate reaction is suppressed, and the concrete structure 73 located in the vicinity of the mortar filling portion 75 penetrates from the mortar filling portion 75 as in FIG. the lithium nitrite (LiNO2), lithium ion (Li ⁺⁾ reacts with the silica component of the silica aggregate 23 insoluble reaction products on the surface (L Since ₂ O × Sio ₂₎ layer 26 is formed, aggregate reaction is suppressed.

Figures 13 (a) to 13 (c) show a mortar spraying layer with a diameter (Φ) = 50.0mm and a thickness of less than 100mm by the dry mortar spraying method, respectively. It is a figure which shows the result of having performed. (A) has a curing period of 28 days and an average intensity of 66.0 (N / mm ² ), (b) has a curing period of 7 days and has an average intensity of 48.1 (N / mm ² ), and (c) has a curing period of 4 The average intensity was 42.1 (N / mm ² ) per day.

Figures 14 (a) to 14 (c) show a strength test by forming a mortar spray layer with a diameter (Φ) = 50.0 mm and a thickness of less than 100 mm by wet mortar spraying method, and changing the curing period by curing in the field. It is a figure which shows the result of having performed. (A) has a curing period of 28 days and an average intensity of 48.7 (N / mm ² ), (b) has a curing period of 7 days and has an average intensity of 34.6 (N / mm ² ), and (c) has a curing period of 4 The average intensity was 30.6 (N / mm ² ) per day. As is apparent from FIGS. 13 and 14, it can be seen that the mortar layer formed by the dry mortar spraying method has higher tensile strength than the mortar layer formed by the wet mortar spraying method, that is, it is difficult to peel off.

  Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various modifications can be made within the scope of the technical idea described in the claims and the specification and drawings. Is possible. It should be noted that any shape, structure, and material not directly described in the specification and drawings are within the scope of the technical idea of the present invention as long as the effects and advantages of the present invention are exhibited.

It is a figure which shows the structural example of a bridge pier top part. It is a figure which shows the concrete damage part near the iron material of a bridge pier, and its removal state. It is a figure which shows the example which sprays and fills the mortar to the concrete damage removal part of the iron material vicinity of a bridge pier. It is a figure which shows the example which sprays and fills the mortar to the concrete damage removal part of the iron material vicinity of a bridge pier. It is a figure for demonstrating the damage and reproduction | regeneration mechanism of the passive film of the iron material in concrete. It is a figure for demonstrating the aggregate reaction of concrete, and the mechanism of the suppression. It is a figure which shows the outline | summary of dry-type mortar spraying. It is a figure which shows the outline | summary of wet mortar spraying. It is a figure which shows schematic structure of a dry-type mortar spraying apparatus. It is a figure which shows schematic structure of a wet mortar spraying apparatus. It is a figure for demonstrating the mechanism of aggregate reaction suppression at the time of forming the mortar layer containing lithium nitrite on the surface of a concrete structure. It is a figure for demonstrating the suppression mechanism of the aggregate reaction at the time of filling the mortar containing lithium nitrite in the concrete removal part of a concrete structure. It is a figure which shows the result of the intensity | strength test of the mortar layer formed with the dry mortar spraying method which concerns on this invention. It is a figure which shows the result of the strength test of the mortar layer formed with the wet mortar spraying method which concerns on this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Bridge pier 11 Bridge 12 Snowmelt water 13 Iron 14 Concrete 15 Crack and crack 16 Concrete damage part 17 Concrete removal part 18 Rust prevention layer 19 Mortar filling layer 20 Finishing mortar layer 21 Surface treatment layer 22 Adhesive material layer 23 Silica aggregate 24 Formation Gel layer 25 Cracks and cracks 26 Reaction product layer 31 Mortar spray nozzle 32 Dry mortar feeder 33 Compressed air 34 Hose 35 Mixture (dry mortar)
36 liquid mixture 37 mortar 41 mortar spray nozzle 42 mortar feeder 43 hose 44 mortar 45 compressed air 51 silo 52 sprayer 53 compressor 54 supply pipe 55 hopper 56 cutting machine 61 silo 62 mortar feeder 63 compressor 64 hopper 65 mortar stirring extrusion Machine 67 Motor 68 Hose 71 Concrete structure 72 Mortar layer 73 Concrete structure 74 Concrete removal part 75 Mortar filling part

Claims (12)

  A mortar spraying method characterized by spraying a mortar formed by mixing a polymer cement, an aggregate, water, and a lithium nitrite solution onto a predetermined portion of a concrete structure through a mortar spray nozzle. In the mortar spraying method according to claim 1,
The mortar is sprayed from the mortar spray nozzle by pumping the polymer cement and aggregate mixture to the mortar spray nozzle by compressed air through a hose, and immediately before or in the mortar spray nozzle. A mortar spraying method comprising mixing the water and lithium nitrite solution into the mixture to form a mortar, and spraying from the mortar spray nozzle. In the mortar spraying method according to claim 1,
The mortar spraying from the mortar spray nozzle is performed by transferring a mortar formed by mixing the polymer cement, aggregate, water and lithium nitrite solution to the mortar spray nozzle through a hose and compressing the mortar spray nozzle. Mortar spraying method characterized by supplying air and spraying. Remove the damaged part of the concrete where cracks and cracks were generated by corrosion of the iron structure of the concrete structure embedded with reinforcing iron material by removing the iron material, and fill the concrete removed part with mortar to repair the damaged part A method for repairing a damaged part of a concrete structure,
Repairing a damaged part of a concrete structure, wherein the concrete removal part excluding the iron material is filled with mortar formed by mixing polymer cement, aggregate, water and lithium nitrite solution through a mortar spray nozzle. Method. The method for repairing a damaged part of a concrete structure according to claim 4,
The mortar spraying from the mortar spray nozzle is carried out by feeding the mixture of the polymer cement and the aggregate to the mortar spray nozzle with compressed air through a hose, and immediately before the mortar spray nozzle or in the mortar spray nozzle. A method for repairing a damaged part of a concrete structure, wherein the mixture is mixed with the water and lithium nitrite solution to form a mortar and sprayed from the mortar spray nozzle. The method for repairing a damaged part of a concrete structure according to claim 4,
The mortar spraying from the mortar spray nozzle is performed by transferring a mortar formed by mixing the polymer cement, the aggregate, water, and a lithium nitrite solution to the mortar spray nozzle, and supplying compressed air to the mortar spray nozzle. A method for repairing a damaged part of a concrete structure, characterized by spraying. In the damaged part repair method of the concrete structure of Claim 5 or 6,
A method for repairing a damaged part of a concrete structure, comprising: removing a damaged part of concrete by removing the reinforcing bar, and then providing a rust prevention treatment layer in which a rust preventive material is applied to the reinforcing bar. In the damaged part repair method of the concrete structure of Claim 5 or 6,
After removing the damaged part of the concrete excluding the reinforcing bar, the concrete structure damage characterized by providing an adhesive layer coated with an adhesive material that makes the mortar adhere well on the surface of the concrete removed part Department repair method. A method for repairing a damaged part of a concrete structure in which a damaged part of concrete that has cracks or cracks due to an aggregate reaction of the concrete structure is removed, and the concrete removed part is filled with mortar to repair the damaged part. ,
A method for repairing a damaged part of a concrete structure, characterized in that a mortar formed by mixing a polymer cement, an aggregate, water and a lithium nitrite solution is sprayed and filled into the concrete removing part through a mortar spraying nozzle. The method for repairing a damaged portion of a concrete structure according to claim 9,
The mortar spraying from the mortar spray nozzle is carried out by feeding the mixture of the polymer cement and the aggregate to the mortar spray nozzle with compressed air through a hose, and immediately before the mortar spray nozzle or in the mortar spray nozzle. A method for repairing a damaged part of a concrete structure, wherein the mixture is mixed with the water and lithium nitrite solution to form a mortar and sprayed from the mortar spray nozzle. The method for repairing a damaged portion of a concrete structure according to claim 9,
The mortar spraying from the mortar spray nozzle is performed by transferring a mortar formed by mixing the polymer cement, the aggregate, water, and a lithium nitrite solution to the mortar spray nozzle, and supplying compressed air to the mortar spray nozzle. A method for repairing a damaged part of a concrete structure, characterized by spraying. Remove the damaged part of concrete that has cracked or cracked due to iron corrosion and / or aggregate reaction for reinforcing concrete structure, and mix the polymer cement, aggregate, water and lithium nitrite solution into the concrete removed part. Concrete structure characterized by filling and repairing mortar.

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