JP2013189353A - Mortar application method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a mortar application method in which the promotion of the hydration reaction is reasonably suppressed and the difference in initiation of the setting time is hardly caused, even in the case where the condition to prepare a mortar is different and the mortar is excessively kneaded.SOLUTION: A mortar application method includes a step of continuously kneading a hydraulic composition and an aqueous solution to form a mortar, and a step of applying the mortar at a construction site, wherein the hydraulic composition contains a portland cement as a hydraulic component, and the aqueous solution is a calcium hydroxide aqueous solution.

Description

  The present invention relates to a mortar construction method used for civil engineering and building construction.

  In various construction works in the civil engineering and construction fields, grout materials and self-leveling materials are used depending on the construction site, and materials having fluidity, workability, and good curing properties have been proposed.

  Patent Document 1 discloses a grout material having good fluidity and material separation resistance and excellent crack resistance after curing. Since it has material separation resistance, a hydraulic composition and water are mixed with a mixer. Are continuously kneaded, and the obtained slurry can be pumped over a long distance with a pump to be forwarded to the construction site.

  In addition, Patent Document 2 discloses that a hydraulic substance is kneaded with a lime-based aqueous solution for the purpose of providing a cured body of a hydraulic substance that can reduce the water evaporation rate and obtain a dense surface. There is disclosed a method for producing a hydraulic substance, characterized in that an uncured hydraulic substance is subjected to a combination of a fine water drop curing and a steam curing or a wet air curing.

JP 2010-95389 A Japanese Patent Laid-Open No. 04-209780

  However, using a mortar generating device at the construction site, the hydraulic composition and water are continuously kneaded, and when the resulting mortar is placed at the construction site, by moving the placement location, handling the hose, etc., There are many cases where construction is temporarily suspended. In that case, the mortar continues to be kneaded while being accommodated in the mortar producing apparatus. When the interruption time is long, the mortar is excessively kneaded, so that the hydration reaction of the mortar is promoted, and the time for the setting to start (start of the setting time) is shortened. As a result, the initial difference in the setting time of the mortar differs greatly depending on the construction location, and the structure does not harden as designed, and the structure becomes discontinuous, which may cause cracks. Therefore, even when the conditions for preparing (kneading) the mortar are different, a mortar in which the hydration reaction is stable and the initial fluctuation of the setting time is small is desired. Here, Patent Document 1 is a technique mainly related to improvement of pumpability by improving fluidity and material separation resistance, and Patent Document 2 mainly reduces the moisture evaporation rate during steam curing and has a dense surface. These prior art documents do not have the technical idea of reducing the influence of the difference in the conditions for adjusting the mortar, which is the subject of the present application, on the initial setting of the setting time.

  Therefore, the present invention provides a mortar construction method in which the conditions for preparing the mortar are different and even when excessively kneaded, the acceleration of the hydration reaction is moderately suppressed, and the initial setting time hardly occurs. With the goal.

  The present inventors have found that the above problem can be solved by using a calcium hydroxide aqueous solution as the aqueous solution constituting the mortar in the step of continuously kneading the hydraulic composition and the aqueous solution to produce the mortar. The invention has been completed.

  That is, the present invention is a mortar construction method having a step of continuously kneading a hydraulic composition and an aqueous solution using a mortar production apparatus to produce mortar and a step of constructing mortar at a construction site. The hydraulic composition provides Portland cement as a hydraulic component, and the aqueous solution is a calcium hydroxide aqueous solution.

  The mortar construction method can construct a stable mortar that is less susceptible to the setting time due to the difference in the preparation conditions due to the stable hydration characteristics that are less susceptible to the kneading time of the mortar generator.

  In the mortar construction method of the present invention, it is preferable that the hydraulic composition further contains fine aggregate and a fluidizing agent, whereby the mortar flow characteristics can be improved more reliably.

  In the mortar construction method of the present invention, when the calcium hydroxide aqueous solution is dissolved in 100 g of the aqueous solution at 25 ° C. in an amount of 0.085 g or more, the influence on the setting time due to the difference in the preparation conditions is more affected. The effect of the present invention that a stable mortar that is difficult to receive can be obtained can be obtained more effectively and reliably.

  In the mortar construction method of the present invention, when the calcium hydroxide aqueous solution is a saturated calcium hydroxide aqueous solution, a stable mortar that is less susceptible to the setting time due to the difference in the preparation conditions can be obtained. The effect of achieving the above can be obtained more effectively and reliably.

  In the mortar construction method according to the present invention, the mortar generating device includes a plurality of blades formed on the outer peripheral surface of the shaft member, and the shaft member rotates to knead the hydraulic composition and the aqueous solution while mixing the hydraulic composition and the aqueous solution. A kneading apparatus provided with a kneading screw for transferring the mortar from the base end side toward the terminal end, a hopper having a hopper screw for transferring the hydraulic composition to the kneading apparatus, and a mortar discharged from the kneading apparatus. It is preferable to include a reservoir for housing, a snake pump for discharging the mortar in the reservoir to the outside, and a transfer pipe for transferring the mortar discharged from the snake pump.

  By using such a mortar generating apparatus, mortar can be generated continuously, mass-placement at the construction site is possible, and the effect of shortening the construction period can be obtained more reliably.

  Moreover, the mortar generating apparatus further includes a hydraulic composition supply apparatus that supplies the hydraulic composition to the hopper, thereby ensuring a large amount of mortar placement.

  Furthermore, the mortar generating device further includes an aqueous solution supply device that supplies the aqueous solution to the kneading device, thereby enabling construction in a place where there is no aqueous solution supply facility.

  When the mortar generating apparatus is mounted on a vehicle, it is possible to more easily move the hydraulic composition to the construction site and perform construction on the site.

  According to the present invention, the conditions for preparing the mortar with the mortar generator at the construction site are different, and even when excessively kneaded, the promotion of the hydration reaction is moderately suppressed, and it is difficult to cause a difference in the initial setting time. The construction method of the mortar which can suppress malfunctions, such as a crack, can be provided.

It is a figure which shows a mortar production | generation apparatus typically. It is a rear view which shows typically the mortar production | generation apparatus mounted in the vehicle. It is a side view which shows typically the mortar production | generation apparatus mounted in the vehicle.

  The mortar construction method of the present invention includes a step of producing a mortar by continuously kneading a hydraulic composition containing Portland cement as a hydraulic component and an aqueous calcium hydroxide solution using a mortar producing apparatus, and constructing the mortar. And a process for construction on site.

  DESCRIPTION OF EMBODIMENTS Preferred embodiments of a mortar construction method according to the present invention will be described below with reference to the drawings.

<Mortar generator>
FIG. 1 is a diagram schematically illustrating a mortar generating apparatus according to the present embodiment. In the mortar generating apparatus according to the present embodiment, a plurality of blades are formed on the outer peripheral surface of the shaft member, and the shaft member rotates in a predetermined direction, thereby kneading the hydraulic composition and the aqueous solution while the proximal end side of the shaft member A kneading device 2b provided with a kneading screw 26 for transferring the kneaded material (mortar) from the end to the end side, a hopper 2a having a hopper screw 22 for transferring the hydraulic composition to the kneading device 2b, and a kneading device A reservoir 2c for storing the mortar discharged from the reservoir, a snake pump 2d for discharging the mortar in the reservoir 2c to the outside, and a transfer pipe 2e for transferring the mortar discharged from the snake pump 2d. It is preferable to provide.

  As shown in FIG. 1, the mortar generating apparatus includes a hopper 2a, a kneading apparatus 2b, a reservoir 2c, a snake pump 2d, a transfer pipe 2e, an operation panel 2f, and a water supply port 27, and a hydraulic composition and an aqueous solution are provided. Continuous kneading produces mortar.

  The hopper 2a supplies the charged hydraulic composition to the kneading apparatus 2b side. The hopper 2a has a wide opening 21 formed in the upper part of the main body of the hopper 2a, and has an opening communicating with the adjacent kneading device 2b in the lower side wall of the main body. And the hopper screw 22 is provided substantially horizontally in the main body lower part of the hopper 2a, and is rotationally driven by the motor 23 installed in the exterior of the hopper 2a. In this case, the rotational driving force by the motor 23 is transmitted to the hopper screw 22 side via the power transmission belt 24. Here, a hydraulic or electric motor 23 is used.

  The hopper screw 22 is formed such that a spiral blade is wound around the outer peripheral surface. Here, the hydraulic composition charged into the charging port 21 is transferred to the kneading device 2 b by the rotational movement of the hopper screw 22.

  The kneading apparatus 2 b includes a kneading chamber 25 and a kneading screw (mixer screw) 26. The kneading chamber 25 has a cylindrical shape (hollow cylindrical shape) and is installed so that the longitudinal direction is substantially horizontal. The kneading chamber 25 is provided with an opening communicating with the lower part in the hopper 2a at one end of the two ends in the longitudinal direction, and an opening communicating with the discharge unit 28 in the vicinity of the other end. Is provided. A mixer screw 26 is installed inside the kneading chamber 25 along the longitudinal direction. The kneading apparatus 2b kneads the hydraulic composition transferred from the hopper 2a by the rotation of the mixer screw 26 in the kneading chamber 25 together with the aqueous solution. Here, a water supply port 27 communicating with the transfer pipe 6b is formed at a predetermined position on the side of the hopper 2a on the side wall of the kneading chamber 25, and the inside of the kneading chamber 25 is connected to the transfer pipe 6b and the water supply port 27. An aqueous solution is supplied to

  The transfer pipe 6b can transfer the aqueous solution by being connected to the aqueous solution supply device at the construction site by a rubber hose or the like. The supply amount of the aqueous solution is adjusted by the operator operating the aqueous solution adjustment valve while visually checking the flow meter. The flow meter and the aqueous solution adjusting valve are disposed in the vicinity of the operation panel 2f, and are particularly preferably disposed in a place that is easy to operate and is easy to see.

  Further, the discharge unit 28 communicates the kneading chamber 25 and the reservoir 2c, and discharges the mortar kneaded in the kneading chamber 25 to the reservoir 2c. The mixer screw 26 is formed integrally with the hopper screw 22 of the hopper 2 a (or is connected and fixed), and is rotated together with the hopper screw 22 by a motor 23.

  The rotation speed of the mixer screw 26 is 300 rpm or more, preferably 400 rpm or more, more preferably 500 rpm or more, and still more preferably 600 rpm or more. Thus, since the rotation speed of the mixer screw 26 is as high as 300 rpm or more, the mortar is more sufficiently kneaded. Here, the rotation speed of the mixer screw 26 can be set to a desired value by an operator operating an operation panel 2f described later.

  The reservoir 2c is for temporarily storing the kneaded material (mortar) discharged from the kneading device 2b via the discharge unit 28. Thus, since the mortar is temporarily stored in the reservoir 2c, the mortar can be discharged to the outside at a desired ratio (discharge amount) from the reservoir 2c by the snake pump 2d.

  The reservoir 2c has a wide opening 29 formed in the upper part of the main body, and a stirrer screw 30 and a transfer screw 31 provided substantially horizontally in the lower part of the main body. Each of the stirrer screw 30 and the transfer screw 31 has a length from substantially one side to the other of two side walls facing each other in the lower part of the main body of the reservoir 2c. The stirrer screw 30 is rotationally driven by a motor 32, and the transfer screw 31 is rotationally driven by a motor 33. The rotational driving force by the motor 33 is transmitted to the transfer screw 31 side via the power transmission belt 34. Here, the motors 32 and 33 are hydraulic or electric.

  An opening communicating with the adjacent snake pump 2d is formed on the lower side wall of the reservoir 2c. Through this opening, the transfer screw 31 in the reservoir 2c and the screw (not shown) in the snake pump 2d are integrally connected (formed). For this reason, the screw in the snake pump 2 d rotates with the rotation of the transfer screw 31. Thus, by rotating the screw in the snake pump 2d, the mortar in the reservoir 2c is discharged to the outside through the transfer pipe 2e and is applied at the construction site.

  The operation panel 2f includes various operation levers for the operator to operate the rotational drive of the hopper screw 22, the mixer screw 26, the stirrer screw 30 and the transfer screw 31 installed in each of the hopper 2a, the kneading device 2b and the reservoir 2c. And various operation switches. Furthermore, the operation panel 2f is connected to a transfer pipe 6b for transferring an aqueous solution as necessary, and has an aqueous solution adjusting valve and a flow meter for adjusting the supply amount of the aqueous solution supplied to the water supply port 27.

  In the mortar generating apparatus configured as described above, the hydraulic composition charged into the hopper 2 a is transferred to the kneading apparatus 2 b by the rotation of the hopper screw 22. In the kneading device 2b, the hydraulic composition transferred from the hopper 2a is kneaded with the aqueous solution supplied through the water supply port 27 by the rotation of the mixer screw 26, and mortar is generated. The mortar generated by the kneading device 2 b is discharged to the reservoir 2 c through the discharge unit 28, and is temporarily stored while being stirred by the rotation of the stirrer screw 30. The stirred mortar is transferred to the snake pump 2d by the rotation of the transfer screw 31, and is further discharged from the snake pump 2d through the transfer pipe 2e to be applied at the construction site.

  The mortar generating apparatus can include a hydraulic composition supply apparatus as necessary. And if it is an apparatus which can automatically supply a powder raw material to the hopper 2a continuously, a commercially available apparatus can be used in combination.

  As shown in FIG. 2 and FIG. 3 as an example of the hydraulic composition supply device, the hydraulic composition tank 5a for automatically supplying the hydraulic composition to the mixer pump and containing the hydraulic composition, It has screw conveyors 5b and 5c for transferring the hydraulic composition in the hydraulic composition tank 5a to the hopper 2a side. A screw conveyor 5c is arranged on the bottom surface of the main body of the hydraulic composition tank 5a, and a discharge port for discharging the hydraulic composition to the screw conveyor 5b side is formed. An opening 53 for receiving a replenishment supply of the raw material is formed.

  The screw conveyor 5b is for transferring the hydraulic composition in the powder raw material tank 5a to the hopper 2a side, and one end of the screw conveyor 5b is disposed at the bottom of the main body of the hydraulic composition tank 5a. The other end is formed with a discharge port 52 for discharging the hydraulic composition. The discharge port 52 is located near the input port 21 of the hopper 2a. In the screw conveyor 5b, the powder raw material discharged from the discharge port of the powder raw material tank 5a is transferred to the discharge port 52, and is discharged from the discharge port 52 to the hopper 2a.

  The mortar generating apparatus can include an aqueous solution supply apparatus as necessary. And if it is an apparatus which can connect with the water supply port 27 and can supply aqueous solution, it can use combining a commercially available apparatus.

  FIG. 2 is a rear view schematically showing the mortar generating device mounted on the vehicle, and FIG. 3 is a side view schematically showing the mortar generating device mounted on the vehicle.

  The mortar generating apparatus can be mounted on a vehicle 71 such as a truck as necessary. For example, as shown in FIG. 2 and FIG. 3, a mortar generating device including a hydraulic composition supply device and an aqueous solution supply device can be disposed in the loading platform portion of the vehicle 71.

  As shown in FIG. 2 and FIG. 3 as an example of the aqueous solution supply device, the aqueous solution supply device includes an aqueous solution tank 6a for storing the aqueous solution, and a transfer pipe for transferring the aqueous solution stored in the aqueous solution tank 6a to the kneading device 2b. 6b, an aqueous solution supply pump 6c that pumps up the aqueous solution stored in the aqueous solution tank 6a, an aqueous solution adjustment valve that adjusts the supply amount of the aqueous solution supplied into the kneading apparatus 2b, and a flow meter. The adjustment of the aqueous solution is performed by the operator operating the aqueous solution adjustment valve while visually checking the flow meter. The flow meter and the aqueous solution adjusting valve are disposed in the vicinity of the operation panel 2f, and are particularly preferably disposed in a place that is easy to operate and is easy to see. For example, the operation panel 2f and a transfer pipe 6b for transferring the aqueous solution may be connected to incorporate an aqueous solution adjusting valve and a flow meter for adjusting the supply amount of the aqueous solution supplied to the water supply port 27 into the operation panel 2f. .

  By using such a mortar generating apparatus, mortar can be generated continuously, mass placement at the construction site becomes possible, and the construction period can be shortened.

<Hydraulic composition>
An example of the hydraulic composition according to the present embodiment will be described. The hydraulic composition of this embodiment contains Portland cement as a hydraulic component.

  As the Portland cement, at least one selected from ordinary Portland cement, early-strength Portland cement, ultra-early strong Portland cement, moderately hot Portland cement, low heat Portland cement and sulfate-resistant Portland cement can be used. From the viewpoint of rapid hardening, it is preferable to use ordinary Portland cement, early-strength Portland cement, or ultra-early-strength Portland cement.

  It is preferable that the hydraulic composition according to the present embodiment further includes a fine aggregate and a fluidizing agent.

  Fine aggregates include silica sand, river sand, land sand, sea sand, crushed sand and other sands, slag fine aggregate, recycled fine aggregate, alumina clinker aggregate, urethane crushed, EVA foam, and foamed resin. It is preferable to select and use the pulverized material as appropriate. In particular, the fine aggregate is preferably selected from sands such as quartz sand, river sand, land sand, sea sand, crushed sand, and alumina clinker aggregate.

  The fine aggregate preferably has a maximum particle size of 1400 μm or less and a content ratio of particles having a particle size of 63 μm or less of 10% by mass or less, a maximum particle size of 1180 μm or less, and a particle size of 63 μm or less. The content ratio of the particles is more preferably 5% by mass or less, the maximum particle diameter is 1000 μm or less, and the content ratio of the particles having a particle diameter of 63 μm or less is further preferably 3% by mass or less.

  The hydraulic composition of the present embodiment can further improve the strength characteristics and dimensional stability of the mortar of the present invention by including a fine aggregate having a particle diameter in the above range.

  The particle diameter of the fine aggregate can be measured by using several sieves having different nominal dimensions as defined in JIS Z 8801: 2006. Further, in this specification, “the maximum particle size is 1400 μm or less” means that when a sieve having a mesh size of 1400 μm is used, the fine aggregate passes through all sieves having a mesh size of 1400 μm. “The content ratio of particles having a diameter of 63 μm or less” refers to the content ratio (% by mass) of the particles passing through the sieve having a sieve size of 63 μm with respect to the entire fine aggregate when a sieve having a sieve size of 63 μm is used.

  The content of the fine aggregate is preferably 50 to 400 parts by weight, more preferably 70 to 300 parts by weight, still more preferably 90 to 200 parts by weight, with respect to 100 parts by weight of Portland cement. Preferably it is 100-150 mass parts.

  The hydraulic composition of this embodiment can make the improvement of the strength characteristics and dimensional stability after hardening of the mortar of the present invention more reliable by setting the content of the fine aggregate in the above range.

  The fluidizing agent is selected from commercially available fluidizing agents such as formaldehyde condensate of melamine sulfonic acid, casein, calcium caseinate, polycarboxylic acid, polyether and polyether polycarboxylic acid, which have a water reducing effect. It is preferable to use at least one, and it is particularly preferable to use a commercially available fluidizing agent such as a polyether or polyether polycarboxylic acid.

  It is preferable that the hydraulic composition of the present embodiment contains a fluidizing agent because a mortar having high fluidity can be obtained even in kneading with a smaller amount of an aqueous solution. Further, it is preferable because the strength property is further improved by reducing the aqueous solution / hydraulic composition ratio without lowering the fluidity.

  The content of the fluidizing agent is preferably 0.04 to 2.0 parts by mass, more preferably 0.06 to 1.0 parts by mass, and still more preferably 0 with respect to 100 parts by mass of Portland cement. 0.08 to 0.5 parts by mass, particularly preferably 0.1 to 0.2 parts by mass.

  The hydraulic composition of this embodiment can make the improvement of the fluidity | liquidity of the mortar of this invention and the intensity | strength property after hardening more reliably by making content of a fluidizing agent into the above-mentioned range.

  As described above, the hydraulic composition according to the present embodiment includes Portland cement. Furthermore, it is preferable that a fine aggregate and a fluidizing agent are included, and the fluidity, strength characteristics after hardening, and dimensional stability of the mortar of the present invention are more preferable.

  In addition to the above components, the hydraulic composition of the present embodiment is within a range that does not impair the characteristics of the mortar of the present invention, gypsum, alumina cement, inorganic fine powder, inorganic expansion material, metal expansion material, setting adjustment An agent, a thickener, an antifoaming agent, a shrinkage reducing agent, a resin powder, and the like can be suitably added.

  Gypsum, such as anhydrous gypsum, hemihydrate gypsum, and dihydrate gypsum, can be suitably added as one or a mixture of two or more regardless of the type. By adding gypsum, the dimensional stability of the mortar is improved more reliably.

  Several types of alumina cements with different mineral compositions are known and commercially available, but the main component is monocalcium aluminate (CA), and commercially available products can be suitably added regardless of the type. . By adding alumina cement, it is possible to more surely improve the hardening characteristics (fast curing) and dimensional stability of the mortar.

  Inorganic fine powder is a fine powder such as fly ash, blast furnace slag, steelmaking slag, various ceramics, calcium carbonate, etc., or a fine powder in which the average circularity of the particles is increased by grinding treatment, heat treatment, classification treatment, etc. Two or more kinds can be mixed and added suitably. By adding inorganic fine powder, the flowability and dimensional stability of the mortar are improved more reliably.

  Examples of the inorganic expansive material include auin in the calcium sulfoaluminate system, quick lime, quick lime-gypsum system, calcined dolomite, and the like in the lime system, and at least one selected from these can be suitably added. As the lime-based expansion material, quick lime and quick lime-gypsum are preferable, and quick lime-gypsum is particularly preferable. By adding an inorganic expansion material, the mortar's dimensional stability is improved more reliably.

  The metal-based expansion material can be suitably added with metal powder such as aluminum powder and iron powder. Among these, it is particularly preferable to add aluminum powder from the aspect of specific gravity. As the aluminum powder, a material according to the second type of JIS K 5906: 1998 “Aluminum Pigment for Coating” can be suitably added. By adding a metal-based expansion material, the improvement in dimensional stability of the mortar is further ensured.

  The setting modifier includes a setting accelerator that accelerates the hydration reaction and a setting retarder that delays the hydration reaction. Detailed adjustment of mortar fluidity, fluidity retention, and setting time is ensured by appropriately selecting and adding each component (type), amount and ratio of the setting accelerator and setting retarder. To.

  As the thickener, cellulose, protein, latex, water-soluble polymer, and the like can be suitably added. Among them, it is preferable to add a cellulose thickener. By adding a thickener, the material separation resistance of the mortar is further improved.

  As the antifoaming agent, known substances such as synthetic substances such as silicone, alcohol, polyether and mineral oil, or natural substances derived from plants can be suitably added. By adding an antifoaming agent, the surface properties and strength characteristics of the mortar are improved more reliably.

  A known shrinkage reducing agent can be suitably added to the shrinkage reducing agent. As the shrinkage reducing agent, those having an alkylene oxide polymer in the skeleton of the chemical structure are preferable. For example, it can be suitably selected from generally known materials such as polyalkylene glycols such as polypropylene glycol and poly (propylene / ethylene) glycol, and alkoxy poly (propylene / ethylene) glycol having 1 to 6 carbon atoms. By adding a shrinkage reducing agent, the dimensional stability of the mortar is further improved.

  The type of the resin powder is not particularly limited, and a resin powder produced by a known production method can be suitably added, and a resin powder in which an antiblocking agent is mainly attached to the surface of the resin is preferred. Further, a resin powder obtained by removing the solvent from the aqueous polymer dispersion by a method such as spraying or freeze drying, and drying is preferable. The resin powder is made of an acrylic polymer such as ethylene / vinyl acetate copolymer, vinyl acetate / veova copolymer, or vinyl acetate / veova / acrylic copolymer, styrene / acrylic copolymer, and acrylic / methacrylic copolymer. A resin powder mainly composed of a coalescence is preferable. Thereby, the improvement of the surface characteristic at the time of hardening mortar, adhesiveness with a foundation | substrate, and bending strength characteristic is ensured.

<Mortar>
The mortar which concerns on the construction method of the mortar of this invention is obtained by mix | blending and knead | mixing the hydraulic composition and calcium hydroxide aqueous solution which contain Portland cement as a hydraulic component. In addition, the conditions for preparing the mortar (kneader kneading time, rotation speed, etc.) are different, and even when it is excessively kneaded, the promotion of the hydration reaction is moderately suppressed, making it difficult to produce a difference in the initial setting time. Therefore, the calcium hydroxide aqueous solution according to the present embodiment preferably has 0.085 g or more dissolved in 100 g of the aqueous solution at 25 ° C., more preferably 0.113 g or more. Preferably, 0.141 g or more is more preferably dissolved, and 0.168 g or more is particularly preferable. When calcium hydroxide is dissolved in the above-described range, it is more difficult to be affected by the preparation conditions.

  In general, after the Portland cement particles come into contact with water, the particles themselves dissolve and calcium ions are released. Thereafter, nucleation and hydrate precipitation occur, which is called hydration reaction. When the mortar containing Portland cement is excessively kneaded, the surface of the Portland cement particles (for example, the electric double layer) is disturbed, so that the dissolution of the particles proceeds excessively, and as a result, the hydration reaction is promoted. By using water as the above-mentioned calcium hydroxide aqueous solution, the thickness of the ion equilibrium layer on the cement particle surface increases, and therefore, even when excessively kneaded, the promotion of the hydration reaction can be moderately suppressed.

  Moreover, the above-mentioned calcium hydroxide aqueous solution is preferable because it is a saturated calcium hydroxide aqueous solution, since it is further ensured that the hydration reaction is less affected by the preparation conditions. Furthermore, if a calcium hydroxide aqueous solution having a predetermined calcium ion concentration is supersaturated with respect to calcium hydroxide, the effect of appropriately suppressing the promotion of the hydration reaction will be greater. A calcium hydroxide aqueous solution is more preferable.

  A commercially available calcium hydroxide can be used. From the viewpoint of solubility in water, the 45 μm residue on the sieve is preferably 0.5% or less, more preferably 0.4% or less, still more preferably 0.3% or less, and particularly preferably 0.15% or less.

  The mortar according to the present embodiment, for example, carries the hydraulic composition into the construction site in the form of a bag, and uses a mixer such as an on-site mixing / kneading device or a hand mixer near the construction site. A mortar can be obtained by blending and kneading a fixed amount of calcium hydroxide aqueous solution. Moreover, when preparing mortar, the flow value of mortar can be adjusted by changing the compounding quantity of calcium hydroxide aqueous solution suitably.

  Here, the flow value means that a pipe made of vinyl chloride having an inner diameter of 50 mm and a height of 100 mm is placed on a glass sheet having a thickness of 5 mm, filled with mortar, and then the pipe is pulled up vertically. After the spread of the mortar stops, the diameter (mm) in two directions at right angles is measured, and the average value is taken as the flow value (mm).

  The amount of the calcium hydroxide aqueous solution is preferably 32 to 52 parts by mass, more preferably 35 to 49 parts by mass, and still more preferably 37 to 47 parts by mass with respect to 100 parts by mass of the hydraulic component. . By mixing the calcium hydroxide aqueous solution with the hydraulic composition within the above range, a mortar having suitable fluidity is obtained.

  The flow value of the mortar of the present embodiment is preferably 160 to 290 mm, more preferably 170 to 280 mm, and still more preferably 180 to 260 mm. By setting the flow value within the above range, a mortar having further excellent fluidity can be obtained.

  The mortar of the present embodiment is prepared by blending a hydraulic composition containing Portland cement as a hydraulic component and an aqueous calcium hydroxide solution and kneading, and after a predetermined time has elapsed, the setting starts (the setting time). First departure). Even if the conditions for preparing the mortar (kneading time and number of rotations of the kneader) differ depending on the construction site, it hardens as designed and does not cause defects such as cracks. It is necessary to keep the difference below a certain level. Here, the first start of the setting time is measured in accordance with the test method described in JIS R 5201: 1997 “Cement physical test method”.

  The difference in the initial setting time is preferably within 30 minutes, more preferably within 20 minutes, and even more preferably within 15 minutes. By setting the difference in the initial setting time within the above range, an excellent cured product free from defects such as cracks can be obtained.

  The preferred embodiment of the present invention has been described above, but the present invention is not limited to the above embodiment.

  Hereinafter, the contents of the present invention will be described in more detail with reference to examples and comparative examples, but the present invention is not limited to the following examples.

[Materials used]
The raw materials shown in (1) to (4) below were prepared.
(1) Hydraulic component / Portland cement, CEM I 42.5R (manufactured by Laferge Germany, Blaine specific surface area = 2960 cm ² / g)
(2) Fine aggregate [S]
・ Silica sand (manufactured by Quarz Werke, Inc., the particle size composition of silica sand measured using a sieve is shown in Table 1)

(3) Fluidizer [PCE]
-Polyether polycarboxylic acid-based fluidizing agent (BASF Construction Polymers, trade name: Melflux2651F)
(4) Aqueous solution / Aqueous solution A: Tap water / aqueous solution B: Saturated calcium hydroxide aqueous solution (calcium hydroxide: manufactured by Ube Materials Co., Ltd., super slaked lime, 45 μm residue 0.1% on the sieve)

  Here, the aqueous solution B was prepared by adding 50 g of the above-mentioned calcium hydroxide to 1000 g of water at 20 ° C., stirring for 3 minutes using a chemistor to dissolve the calcium hydroxide, and then removing undissolved calcium hydroxide. Thus, a saturated aqueous calcium hydroxide solution was obtained.

  Table 2 shows the blending ratio (parts by mass) of the above materials for obtaining the mortars of Examples and Comparative Examples.

[Preparation of mortar]
In a temperature-controlled room with a temperature of 20 ° C. and a humidity of 65%, use a hydraulic composition and an aqueous solution cured at the same temperature as the temperature-controlled room, put 270 g of the aqueous solution shown in Table 2 in a 2 L plastic container, and install a stirrer equipped with turbine blades. A total amount of 1500 g of the hydraulic composition was added while stirring at 300 rpm, and kneaded at 700 rpm for a predetermined time to prepare a mortar. The kneading time was 1 minute, 2 minutes, and 7 minutes.

[Method for evaluating physical properties]
The measurements shown in (1) and (2) below were performed using the obtained mortar.

(1) Flow test A pipe made of vinyl chloride having an inner diameter of 50 mm and a height of 100 mm was placed on a glass sheet having a thickness of 5 mm, filled with mortar, and then the pipe was pulled up vertically. After the spread stopped, the diameters in two directions at right angles were measured, and the average value was taken as the flow value (mm). The evaluation results are shown in Table 3.

(2) Setting test (start of setting time)
Measured according to the test method described in JIS R 5201: 1997 “Cement physical test method”. The measurement was performed in a constant temperature room at a temperature of 20 ° C. and a humidity of 65%. Also, the influence on the first train due to the difference in the kneading time was determined as the difference (minutes) of the first train by subtracting the earliest time from the latest train first. The evaluation results are shown in Table 3.

  As shown in Table 3, the effect on the flow value due to the difference in the kneading time was not significantly different in both Example 1 and Comparative Example 1. However, in the mortar of Example 1, the difference in the initial time was 15 minutes, and even if the kneading time was different, the influence on the setting time was small, and it was confirmed that the difference in the initial time was small. On the other hand, in Comparative Example 1, it was confirmed that the difference in the first departure was as large as 80 minutes. In Comparative Example 1, it was confirmed that as the kneading time increased, the hydration reaction was promoted, and the initial setting time was early.

  From the above, the mortar of the present invention obtained by blending and kneading a hydraulic composition containing Portland cement as a hydraulic component and a lime-based aqueous solution accelerates the hydration reaction even when the preparation conditions are different. This is a mortar that moderately suppresses the difference in the initial setting time, and the conditions for preparing the mortar with the mortar generator at the construction site are different. It is possible to provide a mortar construction method that is suppressed, is unlikely to cause a difference in the initial setting time, and can suppress defects such as cracks.

  2a ... hopper, 2b ... kneading device, 2c ... reservoir, 2d ... snake pump, 2e ... transfer pipe, 2f ... operation panel, 21 ... loading port, 22 ... hopper screw, 23 ... motor, 24 ... power transmission belt, 25 ... Kneading chamber, 26 ... kneading screw, 27 ... water supply port, 28 ... discharge port, 29 ... expanding part, 30 ... stirrer screw, 31 ... transfer screw, 32, 33 ... motor, 34 ... power transmission belt, 5a ... hydraulic Composition tank, 5b, 5c ... screw conveyor, 51 ... hydraulic composition, 52 ... discharge port, 53 ... opening, 6a ... aqueous solution tank, 6b ... transfer pipe, 6c ... aqueous solution pump, 71 ... vehicle.

Claims (8)

Using a mortar generating apparatus, a hydraulic composition and an aqueous solution are continuously kneaded to form a mortar, and a step of constructing the mortar at a construction site, and a mortar construction method,
The hydraulic composition includes Portland cement as a hydraulic component,
The mortar construction method, wherein the aqueous solution is an aqueous calcium hydroxide solution.   The mortar construction method according to claim 1, wherein the hydraulic composition further includes a fine aggregate and a fluidizing agent.   The said calcium hydroxide aqueous solution is the construction method of the mortar of Claim 1 or Claim 2 in which calcium hydroxide is melt | dissolving 0.085g or more in 100 g of this aqueous solution at 25 degreeC.   The said calcium hydroxide aqueous solution is the construction method of the mortar of Claims 1-3 which is saturated calcium hydroxide aqueous solution. The mortar generator is
A plurality of blades are formed on the outer peripheral surface of the shaft member, and when the shaft member rotates, the mortar is transferred from the base end side to the terminal end side of the shaft member while kneading the hydraulic composition and the aqueous solution. A kneading device provided with a kneading screw,
A hopper having a hopper screw for transferring the hydraulic composition to the kneading device;
A reservoir for containing the mortar discharged from the kneading device;
A snake pump for discharging the mortar in the reservoir to the outside;
A transfer pipe for transferring the mortar discharged from the snake pump,
The construction method of the mortar of any one of Claims 1-4. The mortar generating device further includes a hydraulic composition supply device that supplies the hydraulic composition to the hopper.
The construction method of the mortar of Claim 5. An aqueous solution supply device for supplying the aqueous solution to the kneading device;
The construction method of the mortar of Claim 5 or Claim 6. The mortar generating device is mounted on a vehicle,
The construction method of the mortar of any one of Claims 5-7.

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