JP2018058724A - Mortar kneaded product for filler, additive, and infilling-injecting-filling method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an additive and a mortal kneaded product, for obtaining a mortar kneaded product for a filler which has a suitable curing rate and flow characteristics capable of performing long-distance transportation by compression with a pump, in which a cured body has a predetermined hardness and hardly causes the reduction of its volume; and to provide an infilling-injecting-filling method.SOLUTION: This invention relates to: an additive, the aqueous solution comprising an effective solid constituent in a total solid content of 20-45 wt.%, the effective solid constituent comprising 10-50 wt.% of polycarboxylic acid compounds, 40-80 wt.% of calcium nitrate, calcium nitrite or their mixture, and 0-20 wt.% of oxycarboxylic acid compound or sugar compounds; a mortar kneaded product for a filler, comprising 100 pts.wt. of cement, 40-200 pts.wt. of a particle admixture having 30 wt.% or larger of calcium carbonate component, 50-100 pts.wt. of water, and 0.5-5 pts.wt. of the additive; and an infilling-injecting-filling method using the kneaded product.SELECTED DRAWING: Figure 1

Description

  In the present invention, after the primary lining of the shield work is completed, the resin concrete panel and the gap in the part where the plastic segment is installed as the secondary lining, the reinforcement of the existing canal, the three-sided canal, and other pipes are repaired. High-strength fine particle mortar kneaded material that has the necessary compressive strength and is used as a filler (grouting material) excellent in long-distance pumping when filling the gap of the part where the pipe of the secondary product is installed, and its It relates to the injection method.

  Conventionally, methods that use resin concrete panels and other materials for water channel repair are generally used, such as an adhesive method that injects an epoxy resin adhesive into the gap between the existing water channel and the repair material, or non-shrink mortar. The anchor method is used. The non-shrinking mortar that is a filler (grouting material) in this anchor method exhibits high strength, and if the mortar itself does not shrink and can be filled without gaps in the gap, the purpose of repair work can be achieved. However, in the mortar conventionally used, since hardening starts about 30 minutes after kneading, it has been necessary to knead and fill at the construction site. Further, fine aggregates such as fine sand are used, and the filling property is not sufficient.

  On the other hand, various infrastructures are reaching the end of their lives in Japan, and reinforcement and repair are urgently needed. And the scale is long even if one pipe is taken, and unlike the time when it was constructed, there are limited work yards that can be constructed for repair work instead of new construction work, so how efficient can you work? Has been questioned.

Under such circumstances, in order to efficiently carry out the reinforcement repair work, the material that fills the gap between the existing water channel and the repair material is manufactured not in the mine but outside the mine, and then pumped by a pump or the like, It must be able to be filled in place. In this case, what is required of the filler is that it can exhibit a predetermined strength, has fluidity that can be pumped without being cured for a certain period of time, does not cause breathing, and has almost no volume reduction. That is, as a characteristic required for the mortar kneaded material for filler, the mortar can also be used as the amount of cement to obtain a predetermined post-cure strength (generally, a 4-week strength of 21 N / mm ² or more in a uniaxial compressive strength test). It is possible to pump long-distance pumping, and it has an appropriate curing start time and curing speed without causing breathing, and does not start curing during pumping. It is required to start curing immediately.

  So far, various admixtures and additives used in various cement compositions that exhibit strength, maintain fluidity, and do not cause breathing have been proposed. In Patent Document 1, as an additive for a ground improvement cement composition for a jet grout method, an alkali hydrolyzate of an olefin, maleic anhydride, a copolymer, a sodium salt such as sodium nitrite, and an oxycarboxylic acid compound are further included. The additive consisting of each component is shown. This additive promotes uniform mixing of cement milk with excavated soil, improves the fluidity of slime, lowers the injection rate, reduces the amount of building sludge, and at the same time ensures the early strength. The present invention is directed to a cement composition for improvement (see Patent Document 1, paragraph [0004]) and does not satisfy the characteristics required for the filler described above.

Further, Patent Document 2 proposes a cement slurry made of cement, a fine powder of polazone, water, a water reducing agent (polycarboxylic acid type, etc.) and a calcium salt (calcium nitrite, calcium nitrate, etc.). The cement slurry of this document has a high fluidity and a relatively high curing rate so as not to cause a delay in setting and a decrease in productivity, and on the other hand, a cement exhibiting an ultra high strength exceeding a compressive strength of 100 MPa. It is provided as a slurry. A micro filler effect and a cement dispersing effect are produced by addition of a fine powder of polarazone, and the fluidity of the slurry is improved. After curing, the cured body is densified to improve the compressive strength (Patent Document 2). , Paragraph [0008]), in order to further increase the strength, it is considered preferable to blend granular aggregates, metal fibers and organic fibers. Furthermore, Patent Document 3 proposes a cement composition containing cement, fine powder and inorganic powder having a specific surface area, alkaline earth metal salt, fine aggregate, and water reducing agent. Here, the alkaline earth metal is calcium nitrate and / or calcium nitrite, and the water reducing agent uses a polycarboxylic acid ether-based high-performance water reducing agent, and maintains high fluidity, while compressing in the same manner as in Patent Document 2. This is achieved by specifying the blending ratio of each of these materials in order to develop an ultra-high strength with a strength of 100 N / mm ² (MPa) or more (see Patent Document 3, paragraph [0007]). Similarly, an embodiment in which metal fibers and organic fibers are added in order to further increase the strength after curing with the aim of ultra-high strength is also shown (Patent Document 3, paragraph [0016]). As described above, the cement compositions disclosed in Patent Documents 2 and 3 are excellent in strength of the cured body, but are not necessarily suitable as a filler for the purpose of injection into gaps or splits.

  Patent Document 4 shows a cement composition containing calcium nitrite, a polycarboxylic acid-based water reducing agent, and a melamine-based water reducing agent in various cements as a cement composition for concrete pavement, and is rapidly hardened after the usage time has elapsed. A cement composition having excellent fluidity before curing and excellent strength after curing while maintaining the properties is shown. However, this cement composition does not necessarily realize excellent workability and physical properties after curing as a filler. Further, Patent Document 5 also shows a cement composition for paving, a cement composition containing Portland cement, a polycarboxylic acid-based admixture, and at least one of calcium nitrate and calcium nitrite. There has been proposed a cement composition that can maintain the properties for a relatively long period of time and can obtain a hardened cement body that can obtain a practical strength in a relatively short time at a low cost. Although these cement compositions are cement compositions having fluidity before curing and an appropriate curing rate for pavement use, they do not have sufficient characteristics as fillers.

Japanese Patent Laid-Open No. 2007-92016 JP 2002-37653 A JP 2010-228953 A JP 2010-285338 A JP 2013-67536 A

In the mortar kneaded material for filler, the unit cement amount is increased in order that the cured product of the kneaded material obtains a predetermined strength (for example, a four-week strength of 21 N / mm ² or more in a uniaxial compressive strength test). However, an increase in the amount of cement used increases the viscosity of the mortar, making pumping difficult. On the other hand, if the water / cement ratio (W / C) is increased to increase the unit water amount in order to facilitate pumping, breathing is likely to occur. In addition, mortar kneaded materials for filling materials used for backfilling and filling and filling in concrete lining and reinforcement repair work in existing waterways, shields, and tunnels are pumped over long distances for a certain period of time after kneading. However, it is required that the fluidity is maintained, has an appropriate curing rate after a certain period of time, the cured body has a predetermined strength, and has almost no volume reduction.

  Therefore, the problem in the present invention is that the kneaded material has a flow characteristic capable of being pumped over a long distance, which is a characteristic required as a mortar kneaded material for a filler used in the above-described filling and filling method, and an appropriate curing speed. Is to provide an additive and a mortar kneaded material and to provide an injection filling method for obtaining a mortar kneaded material for filler having a predetermined strength and almost no volume reduction.

  The additive of the present invention is an additive used for a mortar kneaded material for filler containing 100 parts by weight of cement and 40 to 200 parts by weight of a fine particle admixture containing 30% by weight or more of calcium carbonate component. An effective solid component composed of 10 to 50% by weight of an acid compound, 40 to 80% by weight of calcium nitrate, calcium nitrite, or a mixture thereof, and 0 to 20% by weight of an oxycarboxylic acid compound or a sugar compound. It is characterized by being an aqueous solution containing a total solid concentration of wt%.

  As described above, the additive of the present invention is an aqueous solution prepared by mixing a polycarboxylic acid compound, one of or both of calcium nitrate and calcium nitrite, and an oxycarboxylic acid or a sugar compound added as necessary. It is an additive used to knead cement and the fine particle admixture to obtain a mortar kneaded product.

  And the mortar kneaded material for filler provided in the present invention includes 100 parts by weight of cement, 40 to 200 parts by weight of a fine particle admixture having a calcium carbonate component of 30% by weight or more, 50 to 100 parts by weight of water, and the above. Contains 0.5 to 5 parts by weight of the listed additives. And the manufacturing method of the mortar kneaded material for fillers of this invention puts 0.5-5 weight part of additives of Claim 1 in 50-100 weight part of water to a grout mixer, and stirs and mixes, It is preferable to add 100 parts by weight of cement and 40 to 200 parts by weight of a fine particle admixture having a calcium carbonate component of 30% by weight or more, and knead and knead. However, if necessary, the mixing order may be changed and stirred and mixed. it can.

  The present invention also provides an injection filling method characterized by pumping and filling the above mortar kneaded material for filler to construction sites in existing water channels, shields and tunnels.

  In the mortar kneaded material for filler using the additive of the present invention, the amount of cement used can be reduced as much as possible by using a fine particle admixture having a calcium carbonate component of 30% by weight or more. Realized. In addition, the amount of cement used is increased by the interaction of calcium nitrate, calcium nitrite, which is a component of the additive, or a water-soluble calcium salt, which is a mixture thereof, with the fine particle admixture mainly composed of calcium carbonate. It shows the same strength expression effect. This water-soluble calcium salt also has the effect of promoting the setting of cement. In the mortar kneaded product of the present invention, calcium ions are supersaturated with the fine particle admixture mainly composed of calcium carbonate, and the crystal growth of cement hydrate is promoted. As a result, the curing reaction of the mortar kneaded product is promoted. This acceleration of the curing reaction not only resulted in a rapid curing rate after a lapse of a certain time after kneading, but also increased the amount of cement used as a binder by promoting crystal growth of cement hydrate. Mortar kneading is also preferable for fillers because it has the same effect and can increase the compressive strength of the hardened body without increasing the unit cement amount of cement. It becomes a thing.

  Also, by adding a polycarboxylic acid compound in the additive, even if the water / cement ratio (W / C) value is lowered, the dispersibility of the cement particles is maintained, the fluidity is improved, and the breathing is suppressed. In this way, it can maintain the properties of the fresh mortar state for the required time and realize long-distance pumping. Furthermore, the oxycarboxylic acid or sugar compound added as necessary acts as a setting retarder, and can adjust the time for maintaining the properties of the fresh mortar state, in combination with the above water-soluble calcium salt, By adjusting the blending ratio within the range, it is possible to appropriately adjust the necessary time for maintaining fluidity.

  In addition, the additive of the present invention is blended with each component showing the effect as described above, and is used as an all-in-one additive tailored to the situation at the site, so it can be used easily at the site and work efficiency is improved. It can be set as the additive which contributes to. That is, the required values for the flow characteristics and the curing characteristics of the mortar kneaded material are not always constant, and the required characteristics change depending on the construction conditions. However, the additive of the present invention includes a polycarboxylic acid compound, calcium nitrate, calcium nitrite. Or a mixture thereof, and an aqueous solution containing an effective solid component composed of an oxycarboxylic acid compound or a sugar compound added as necessary, so that the ratio of each effective solid component is changed within the above-mentioned range. Additives can be easily formulated, and various types of additives that provide mortar characteristics that can be applied under various construction conditions can be obtained. It becomes an additive that can be used easily in the field.

It is explanatory drawing of the kneading | mixing pumping plant of a mortar kneaded material.

  Hereinafter, embodiments of the present invention will be described.

  The additive of the present invention is an additive used for a mortar kneaded material for filler containing 100 parts by weight of cement and 40 to 200 parts by weight of a fine particle admixture having a calcium carbonate component of 30% by weight or more. An effective solid component composed of 10 to 50% by weight of carboxylic acid compound, 40 to 80% by weight of calcium nitrate, calcium nitrite, or a mixture thereof, and 0 to 20% by weight of oxycarboxylic acid compound or sugar compound An aqueous solution containing a total solid concentration of 45% by weight. Furthermore, in addition to these effective solid components, if necessary, an antifoaming agent or an air entraining agent may be added as an air amount adjusting agent for the mortar kneaded product.

  In the mortar kneaded product, if the content of the fine particle admixture is less than 40 parts by weight with respect to 100 parts by weight of cement, the viscosity of the mortar increases and pumping becomes difficult. On the other hand, if the content exceeds 200 parts by weight, the effect of cement as a binder is limited, the effect of strength development is reduced, and it becomes difficult to supplement these effects with additives.

  The range of the composition ratio of the effective solid component of the additive is as described above, and if it deviates from the range, the flowability of fresh mortar, which is a preferable characteristic of the mortar kneaded material, is adjusted even if the ratio of each component is adjusted. Breathing is suppressed while maintaining the above, and after a lapse of a certain period of time (with the additive of the present invention, the fluidity can be maintained for 3 hours or more), a rapid hardening promoting effect is exhibited and a cured body having excellent strength is obtained. It becomes difficult to make an additive. In addition, when the effective solid component concentration is less than 20% by weight, the amount added to the mortar kneaded product increases, and when the concentration exceeds 45% by weight, it is difficult to make a one-component aqueous solution depending on the type of the active component. There is.

The cement of the present invention is ordinary Portland cement, early-strength Portland cement, medium heat Portland cement, low heat Portland cement, blast furnace cement, fly ash cement, silica cement as defined in JIS R 5210-5213. Preferably used. The fine particle admixture is a fine powder containing at least 30% by weight of a calcium carbonate component, and is obtained by drying and grinding limestone, which is a natural mineral. The fine particle admixture can be used if it is in the form of fine powder, and the particle size is not particularly limited, but those having an average particle size of 50 μm or less are preferably used. And the fine powder which adjusted the particle size so that a specific surface area may be 3000-8000 cm < ² > / g is preferable. Moreover, fly ash, slag fine powder, etc. can be used together as needed.

  The above-mentioned polycarboxylic acid compound is a compound used for a product marketed as a polycarboxylic acid-based water reducing agent as a chemical admixture, and is a comb polymer compound having polyethylene oxide in the side chain. The oxycarboxylic acid compound is a carboxylic acid compound having a hydroxyl group, and examples thereof include gluconic acid, glycolic acid, citric acid, malic acid, lactic acid, tartaric acid, and water-soluble salts thereof. Examples of the sugar compound include glucose, fructose, sucrose, lactose, and maltose.

  The additive of the present invention is dissolved in an effective solid component having the above-described ratio so as to have a solid component concentration of 20 to 45% by weight to form a one-component aqueous solution. As an effective method for adding to a mortar kneaded material for filler, first, 50 to 100 parts by weight of water and 0.5 to 5 parts by weight of an additive are added to a grout mixer, and the mixture is stirred and mixed. It is preferable to add 40 to 200 parts by weight and 100 parts by weight of cement in this order and knead, but if necessary, the order of addition can be changed and stirred and mixed. Although kneading depends on the mixer used, stirring and kneading is carried out for about 5 minutes after charging all the materials to obtain a mortar kneaded product. And this mortar kneaded material can be pumped for a long distance with a grout pump to the pouring and filling site, and pouring and filling work can be performed.

Examples will be shown below to describe the present invention more specifically. In the mortar kneading and pumping plant shown in FIG. 1, water, additive, and fine particle admixture per 1 m ^{3 of} mortar each measured based on the formulation of each example shown in Table 1 and Table 2 (high flow MP grout) ) And cement (ordinary Portland cement) are sequentially added to the grout mixer 1 and stirred and kneaded for about 5 minutes to produce a mortar kneaded product. The manufactured mortar kneaded material is pumped by a plunger-type main push grout pump 2 and is pumped to an injection port provided at a construction site, and the mortar kneaded material is injected from the injection port to fill and close a predetermined gap. , Solidify and fill with filling. Also, when the pumping extension is long distance, it is further pumped to the injection port provided at the construction site via the relay grout pump 3 installed at the intermediate point in the shield or tunnel, and the mortar mixture is injected from the injection port. The predetermined gap is filled and closed and solidified to perform filling.
Fine particle admixture used
Limestone powder "MP grout for high fluidity" (manufactured by Kizaitect)
Specific gravity 2.7 Specific surface area 5000 cm ² / g

Example 1
As a pumping test of the mortar kneaded material produced as described above, a pumping pipe having a diameter of 50 mm and a length of 2800 m was used, and the relay grout pump 3 was installed at a point of 1400 m to perform pumping. The mortar kneaded mixture is blended as shown in Table 1. The water cement ratio W / C is 84.1%, and the weight ratio of the cement and the fine particle admixture is 1: 1.48. The additive used varied the effective solid component in the composition ratio within the range shown in Table 1.

After the slurry was produced, the mixture was gently stirred in the kneading tank for about 10 minutes, and then the mortar kneaded material was fed under pressure until the 1200 m point at a pressure of about 0.1 to 1.9 MPa and an injection rate of 100 liters. / Min. After that, after arriving at a point of 1400 m, the main push grout pump 2 and the relay grout pump 3 are infused with a pressure of about 0.2 to 1.6 MPa and an injection rate of 60 liters / min. Continued. It was confirmed that the fluidity of the mortar kneaded material was secured even after 3 hours had passed since the start of the pumping. The volume of the cured product obtained by solidifying the mortar kneaded material of Example 1 is hardly observed, the gap is completely filled, and the compressive strength after 4 weeks is maintained at 21 N / mm ² or more. I was able to confirm that.

(Example 2)
Except that the blending of the mortar kneaded material was performed according to the blending shown in Table 2, the production of the mortar kneaded material and the pressure feeding test were performed 1400 m without using a relay grout pump in the same manner as in Example 1. As a result, as in Example 1, it was confirmed that the fluidity of the mortar kneaded material was ensured even after 3 hours had passed since the start of pumping. Further, almost no volume reduction of the cured product in which the mortar kneaded material of Example 2 was consolidated, the gap was completely filled, and the compressive strength after 4 weeks was maintained at 30 N / mm ² or more. It was.

(Example 3)
In the formulation of the mortar kneaded material shown in Table 1, the same formulation as in Example 1 was used except that an additive that does not add an oxycarboxylic acid compound or a sugar compound as a constituent component was used as an effective solid component of the additive. Thus, a mortar kneaded product was manufactured and a pumping test was performed. As a result, it was confirmed that the fluidity of the mortar kneaded material was ensured until 1.5 hours passed, and the characteristics of the solidified cured body were the same as those in Example 1.

1 Grout Mixer 2 Main Push Grout Pump 3 Relay Grout Pump 5 Main Push Pump Flowmeter 6 Relay Pump Flowmeter

Claims (3)

  An additive for use in a mortar kneaded material for filler containing 100 parts by weight of cement and 40 to 200 parts by weight of a fine particle admixture having a calcium carbonate component of 30% by weight or more, comprising 10 to 50% by weight of a polycarboxylic acid compound , Calcium nitrate, calcium nitrite, or a mixture thereof in an amount of 40 to 80% by weight, an effective solid component composed of 0 to 20% by weight of an oxycarboxylic acid compound or a sugar compound, and a total solid concentration of 20 to 45% by weight An additive characterized by being an aqueous solution containing   100 parts by weight of cement, 40 to 200 parts by weight of a fine particle admixture having a calcium carbonate component of 30% by weight or more, 50 to 100 parts by weight of water, and 0.5 to 5 parts by weight of the additive according to claim 1. Mortar kneaded material for filler.   A filling injection filling method characterized by pumping and filling the mortar kneaded material for filler according to claim 2 to a construction site in an existing water channel, a shield and a sluice.

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