Quick-hardening mortar composition for slope surface construction and quick-hardening mortar for slope surface construction

Abstract

To provide a quick-hardening mortar composition for constructing a slope surface, which has fluidity for easy pumping and filling without material separation in repairing or newly constructing a large section with a gradient, and can secure a slope and finish plastering after the filling.SOLUTION: A quick-hardening mortar composition for constructing a slope surface includes: a binder comprising cement, inorganic sulfate and calcium aluminate; a fine aggregate; a water reducing agent; and fibers. The water reducing agent contains at least one water reducing agent selected from the group consisting of a naphthalenesulfonic acid-based water reducing agent, a lignin sulfonic acid-based water reducing agent and a melamine-based water reducing agent. The content of the polycarboxylic acid-based water reducing agent is less than 0.08 pts.mass based on 100 pts.mass of the binder, and the content of the fine aggregate is 110-270 pts.mass based on 100 pts.mass of the binder.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a fast-setting mortar composition for use on inclined surfaces and a fast-setting mortar for use on inclined surfaces. [Background technology]

[0002] Recently, cementitious repair materials are being used in civil engineering and construction work to repair and reinforce concrete structures that have deteriorated due to various factors. Examples of cementitious repair materials include plastering mortar for small cross-section repair, pourable filling mortar for large cross-section repair where formwork can be installed, and sprayable mortar for large cross-section repair where formwork cannot be installed.

[0003] On the other hand, for repair and new construction of roads, railways, etc., there are restrictions on the period of closure due to construction, so quick-hardening mortar is often used for emergency repair work and nighttime work.

[0004] Examples of such materials include an ultra-rapid-hardening, non-shrinkage grout material (see Patent Document 1), which is highly fluid and can be poured and filled into large cross sections, and which is made from a hydraulic inorganic binder consisting of alumina cement, blast furnace slag, Portland cement, gypsum, and hydrated lime; a setting adjuster consisting of aluminum sulfates, lithium salts, and a retarder; a fluidizing agent, a thickener, an antifoaming agent, an expanding agent, and fine aggregate; and a rapid-hardening polymer cement mortar composition (see Patent Document 2), which is easy to work with and can be applied uniformly with a trowel finish and can be used to repair small cross sections, and which contains cement, a polymer, fine aggregate, ultra-rapid-hardening clinker, gypsum, and a setting adjuster, and which is a CaO-Al2O3-based ultra-rapid-hardening clinker that contains a carbonate component. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 11-021160 [Patent Document 2] JP 2014-218415 A Summary of the Invention [Problem to be solved by the invention]

[0006] By the way, in repair, renovation and construction work of dirt floors and passageways with a gradient of 2-3% as a rainwater treatment measure, high-fluidity mortar cannot be used even if the pouring scale is large because it causes sagging, so plastering mortar is poured and the gradient is adjusted by trowel finishing. In other words, there is no mortar that can be poured in large quantities at once on a large cross section, so there is a problem that it requires time and effort and the efficiency of construction is low. Therefore, there is a demand for mortar that can be poured in large quantities by pumping, but can also be plastered with a gradient after pouring. However, high fluidity that can be pumped and hard fluidity that can be plastered are contradictory properties, and it has been difficult to achieve both. In addition, when the fluidity of mortar becomes high, material separation is more likely to occur, which causes problems when using it.

[0007] Therefore, an object of the present invention is to provide a fast-setting mortar composition for application on sloping surfaces, which does not separate into materials, can be easily pumped even in repair or new construction work on large cross-sections involving slopes, has fluidity that allows filling, and can ensure a slope after filling and be plastered for finishing, as well as a fast-setting mortar for application on sloping surfaces. [Means for solving the problem]

[0008] As a result of thorough investigation into the above-mentioned problems, the inventors have discovered that by using a specific type of water reducing agent and adjusting the content of fine aggregate, it is possible to obtain a fast-setting mortar composition for application on inclined surfaces and a fast-setting mortar for application on inclined surfaces that have appropriate fluidity to enable both pumping and plastering.

[0009] That is, the present invention is represented by the following [1] to [7]. [1] A fast-hardening mortar composition for use on inclined surfaces, comprising a binder made of cement, inorganic sulfates, and calcium aluminates, fine aggregate, a water-reducing agent, and fibers, wherein the water-reducing agent comprises at least one water-reducing agent selected from the group consisting of naphthalenesulfonic acid-based water-reducing agents, ligninsulfonic acid-based water-reducing agents, and melamine-based water-reducing agents, the content of the polycarboxylic acid-based water-reducing agent is less than 0.08 parts by mass per 100 parts by mass of the binder, and the content of the fine aggregate is 110 to 270 parts by mass per 100 parts by mass of the binder. [2] The rapid-hardening mortar composition for application on inclined surfaces according to [1], wherein the mass ratio of inorganic sulfate to calcium aluminates ([calcium aluminate content (parts by mass)] / [inorganic sulfate content (parts by mass)]) is 1.5 to 2. [3] The fast-hardening mortar composition for inclined surface application according to [1] or [2], wherein the content of at least one water-reducing agent selected from the group consisting of naphthalenesulfonic acid-based water-reducing agents, ligninsulfonic acid-based water-reducing agents, and melamine-based water-reducing agents is 0.01 to 1 part by mass per 100 parts by mass of the binder. [4] The fast-hardening mortar composition for use on inclined surfaces according to any one of [1] to [3], further comprising a shrinkage-reducing agent. [5] A fast-hardening mortar composition for use on sloped surfaces according to any one of [1] to [4], which is used for pumping. [6] A rapid-setting mortar for application to inclined surfaces, comprising the rapid-setting mortar composition for application to inclined surfaces according to any one of [1] to [5] and water, wherein the water content is 30 to 50 parts by mass per 100 parts by mass of the binder. [7] A fast-hardening mortar for application on inclined surfaces according to [6], having a flow value of 110 to 150 mm at 0 strokes and a flow value of 160 to 260 mm at 15 strokes. Effect of the Invention

[0010] According to the present invention, it is possible to provide a fast-setting mortar composition for application on sloping surfaces and a fast-setting mortar for application on sloping surfaces which do not separate into materials, can be easily pumped even in repair or new construction work on large cross-sections involving slopes, have fluidity that allows filling, and can ensure a slope after filling and allow plastering finishing. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Hereinafter, one embodiment of the present invention will be described in detail.

[0012] In this specification, the term "inclined surface" refers to a construction surface that has an incline (gradient of more than 0%). The gradient (%) of the incline is not particularly limited, but the gradient is preferably 1% to 8%, more preferably 1% to 5%, and even more preferably 1.5% to 4%.

[0013] The rapid-hardening mortar composition for use on inclined surfaces of the present embodiment contains cement, a binder made of an inorganic sulfate and a calcium aluminate, fine aggregate, a water-reducing agent, and fibers.

[0014] In the fast-hardening mortar composition for application on inclined surfaces of this embodiment, the binder is composed of three components: cement, inorganic sulfates, and calcium aluminates.

[0015] Various types of cement can be used, including various types of Portland cement such as ordinary, early strength, super early strength, low heat and medium heat, ecocement, rapid hardening cement, etc. As for cement, ordinary Portland cement and early strength Portland cement are preferred from the viewpoints that they can be pumped and finished with a trowel, the setting time is not easily delayed, the pot life is easily controlled, and it is easy to obtain an appropriate fluidity. One type of cement may be used alone, or two or more types may be used in combination.

[0016] The inorganic sulfate is not limited as long as it can dissolve sulfate ions and react with aluminum ions to form ettringite. Examples of inorganic sulfate include calcium sulfate, sodium sulfate, magnesium sulfate, and lithium sulfate. One type of inorganic sulfate may be used alone, or two or more types may be used in combination. Among inorganic sulfates, calcium sulfate is preferred from the viewpoint of easily improving strength development. Examples of calcium sulfate include gypsums such as anhydrous gypsum, hemihydrate gypsum, and dihydrate gypsum. As gypsums, anhydrous gypsum is preferred from the viewpoint of further improving strength development. The Blaine specific surface area of ​​gypsums is 4000 to 10000 cm from the viewpoint of easily obtaining rapid hardening and strength development. 2 / g, and 5000 to 9000 cm 2 / g, and more preferably 5500 to 8500 cm 2 It is more preferable that the molecular weight is / g.

[0017] The content of the inorganic sulfate is preferably 2 to 25 parts by mass, more preferably 3 to 20 parts by mass, and even more preferably 4 to 15 parts by mass, relative to 100 parts by mass of the binder. When the content of the inorganic sulfate is within the above range, good fluidity and pot life are easily ensured, and strength expression is also excellent.

[0018] Calcium aluminates are classified as C3A, C2A, C, when CaO is C, Al2O3 is A, Na2O is N, Fe2O3 is F, and SiO2 is S. 12 Calcium aluminate with a mineral composition indicated as A7, CA, or CA2, calcium aluminoferrite indicated as C4AF, calcium aluminate with halogen as a solid solution or as a substitute, C3A3·CaF2, etc. 11 Calcium haloaluminates, including calcium fluoroaluminates designated as A7·CaF2, calcium sodium aluminates designated as C8NA3 and C3N2A5, calcium lithium aluminates designated as CA, CA2, C 12A general term for alumina cements whose main components are A7, C2AS, etc., and calcium sulfoaluminates represented as C3A3·CaSO4, etc. As calcium aluminates, alumina cement is preferred. Calcium aluminates can be crystalline, non-crystalline, or a mixture of amorphous and crystalline. Calcium aluminates can be used alone or in combination of two or more. From the viewpoint of further improving early strength development, the fineness of calcium aluminates is set to 3000 cm2 in Blaine specific surface area. 2 / g or more, and 2 / g or more. The fineness of calcium aluminates is preferably 8000 cm2 in terms of Blaine specific surface area. 2 It is preferable that the molecular weight is not more than 1 / g.

[0019] The content of calcium aluminates is preferably 5 to 45 parts by mass, more preferably 8 to 40 parts by mass, and even more preferably 10 to 35 parts by mass, relative to 100 parts by mass of the binder. When the content of calcium aluminates is within the above range, it is easy to achieve both rapid curing and pot life, and it is easy to achieve excellent strength expression.

[0020] The mass ratio of the inorganic sulfate to the calcium aluminates ([calcium aluminate content (parts by mass)] / [inorganic sulfate content (parts by mass)]) is preferably 1.5 to 2, and more preferably 1.7 to 1.9. When the mass ratio of the inorganic sulfate to the calcium aluminates is within the above range, appropriate fluidity that enables pumping and trowel finishing is easily obtained, and the compressive strength is further improved.

[0021] Examples of fine aggregate include river sand, silica sand, crushed sand, kansui stone, limestone sand, slag aggregate, etc. Of these, it is preferable to use silica sand, limestone sand, etc., adjusted to a particle size that does not contain fine powder or coarse aggregate, as the fine aggregate. One type of fine aggregate may be used alone, or two or more types may be used in combination. It is preferable to use fine aggregate with a particle size of 5 mm or less (passing a 5 mm sieve), which is commonly used.

[0022] The particle size of the fine aggregate is not particularly limited, and can be adjusted within the required particle size range of the fine aggregate. The particle size of the fine aggregate can be considered from the coarse aggregate ratio defined by JIS A 1102:2014 "Sieving test method for aggregates". From the viewpoint of obtaining better fluidity when made into mortar and suppressing bleeding, the coarse aggregate ratio of the fine aggregate is preferably 1 to 4, more preferably 1.5 to 3.8, and most preferably 1.8 to 3.5.

[0023] The content of the fine aggregate is 110 to 270 parts by mass relative to 100 parts by mass of the binder. If the content of the fine aggregate is outside the above range, the fluidity that allows both pumping and trowel finishing may not be obtained, material separation may occur, and workability may decrease. The content of the fine aggregate is preferably 120 to 250 parts by mass, more preferably 130 to 220 parts by mass, and even more preferably 140 to 200 parts by mass relative to 100 parts by mass of the binder. If the content of the fine aggregate is within the above range, it is easy to obtain an appropriate fluidity that allows both pumping and trowel finishing, and workability is further improved.

[0024] The water reducing agent includes at least one selected from the group consisting of naphthalenesulfonic acid-based water reducing agents, ligninsulfonic acid-based water reducing agents, and melamine-based water reducing agents. The water reducing agent includes a high-performance water reducing agent, a high-performance air-entraining water reducing agent, an air-entraining water reducing agent, and a superplasticizer. Examples of such water reducing agents include those specified in JIS A 6204:2011 "Chemical admixtures for concrete." The water reducing agents may be used alone or in combination of two or more.

[0025] The content of the water reducing agent is preferably 0.01 to 1 part by mass, more preferably 0.02 to 0.8 parts by mass, and even more preferably 0.03 to 0.7 parts by mass, relative to 100 parts by mass of the binder. If the content of the water reducing agent is within the above range, it is easy to obtain a suitable fluidity that allows pumping and trowel finishing. The content of the polycarboxylic acid water reducing agent in the fast-hardening mortar composition for slope surface application of this embodiment is less than 0.08 parts by mass relative to 100 parts by mass of the binder. If the content of the polycarboxylic acid water reducing agent is 0.08 parts by mass or more, the fluidity becomes too high, causing material separation, or causing sagging when used on a slope surface, making it impossible to finish with a trowel. The content of the polycarboxylic acid water reducing agent is preferably 0.05 parts by mass or less, more preferably 0.02 parts by mass or less, relative to 100 parts by mass of the binder, and even more preferably does not substantially contain a polycarboxylic acid water reducing agent.

[0026] Examples of fibers include organic fibers such as vinylon fibers, polypropylene fibers, nylon fibers, and acrylic fibers; steel fibers; and inorganic fibers such as glass fibers. From the viewpoint of better dispersibility, the fibers are preferably organic fibers, and vinylon fibers and polypropylene fibers are more preferable. One type of fiber may be used alone, or two or more types may be used in combination.

[0027] The length of the fibers is preferably 1 to 30 mm, more preferably 1.5 to 20 mm, and even more preferably 2 to 15 mm. If the length of the fibers is within the above range, the material dispersibility during kneading with mortar is further improved.

[0028] The content of the fibers is preferably 0.01 to 5 parts by mass, more preferably 0.03 to 3 parts by mass, and even more preferably 0.05 to 2 parts by mass, relative to 100 parts by mass of the binder. If the content of the fibers is within the above range, the material dispersion during mortar mixing is maintained, and durability, mainly crack resistance, is further improved.

[0029] The fast-hardening mortar composition for inclined surface application of the present embodiment may contain a hardening accelerator. Examples of hardening accelerators include alkali metal carbonates. The alkali metal carbonate is not particularly limited as long as it is a carbonate of an alkali metal (a Group 1 element of the periodic table excluding hydrogen atoms). Among the alkali metal carbonates, lithium carbonate, sodium carbonate, and potassium carbonate are preferred from the viewpoint of further promoting strength development. The hardening accelerator may be used alone or in combination of two or more kinds.

[0030] The content of the curing accelerator is preferably 0.1 to 2 parts by mass, more preferably 0.2 to 1.5 parts by mass, and even more preferably 0.3 to 1.2 parts by mass, relative to 100 parts by mass of the binder. If the content of the curing accelerator is within the above range, the initial strength development will be even more excellent.

[0031] The fast-hardening mortar composition for inclined surface application of the present embodiment may contain a setting retarder. Examples of setting retarders include organic acids or salts thereof such as citric acid, gluconic acid, malic acid, and tartaric acid; boric acid, borates such as sodium borate, phosphates, and inorganic salts such as alkali metal bicarbonates; and sugars. Among these, citric acid, citrates, tartaric acid, and tartrates are preferred. The setting retarder may be in the form of a powder or a liquid (for example, an aqueous solution, emulsion, or suspension). The setting retarder may be used alone or in combination of two or more types.

[0032] The content of the setting retarder is preferably 0.01 to 1 part by mass, more preferably 0.05 to 0.8 parts by mass, and even more preferably 0.08 to 0.5 parts by mass, relative to 100 parts by mass of the binder. If the content of the setting retarder is within the above range, it is easier to ensure a longer pot life.

[0033] The fast-hardening mortar composition for slope surface application of this embodiment may contain a shrinkage reducing agent. For example, polyoxyalkylene compounds, polyether compounds, alkylene oxide compounds, etc. can be used as the shrinkage reducing agent. Specific examples of the shrinkage reducing agent include polyoxyethylene-alkylaryl ether, polypropylene glycol, lower alcohol alkylene oxide adduct, glycol ether-amino alcohol derivative, polyether, polyoxyalkylene glycol, ethylene oxide methanol adduct, ethylene oxide-propylene oxide polymer, phenyl-ethylene oxide polymer, cycloalkylene-ethylene oxide polymer, dimethylamine-ethylene oxide polymer, etc. The shrinkage reducing agent may be used alone or in combination of two or more.

[0034] The content of the shrinkage reducing agent is preferably 0.1 to 5 parts by mass, more preferably 0.3 to 3 parts by mass, and even more preferably 0.5 to 2 parts by mass, relative to 100 parts by mass of the binder. If the content of the shrinkage reducing agent is within the above range, drying shrinkage after curing can be suppressed and durability can be further improved without causing almost any setting delay.

[0035] The fast-hardening mortar composition for slope construction of this embodiment may contain various admixtures (materials) within the range in which the effects of the present invention are not impaired. Examples of admixtures (materials) include expansive materials, cement polymers, defoamers, foaming agents, waterproofing agents, rust inhibitors, water retention agents, pigments, water repellents, efflorescence inhibitors, blast furnace slag powder, stone powder, earth mineral powder, slag powder, fly ash, silica fume, inorganic fillers, volcanic ash, etc.

[0036] The method for producing the fast-hardening mortar composition for inclined surface construction of this embodiment is not particularly limited, and for example, the composition can be produced by mixing the above-mentioned materials using a mixer such as a gravity mixer such as a V-type mixer or a tilting concrete mixer, a Henschel mixer, a jet mixer, a ribbon mixer, or a paddle mixer.

[0037] The fast-setting mortar composition for inclined surface application of this embodiment can be mixed with water to prepare a fast-setting mortar for inclined surface application, and the water content may be appropriately adjusted according to the application. The water content is preferably 30 to 50 parts by mass, more preferably 33 to 48 parts by mass, and even more preferably 35 to 45 parts by mass, relative to 100 parts by mass of the binder. If the water content is within the above range, it is easy to obtain a suitable fluidity that allows pumping and trowel finishing, and the workability is further improved.

[0038] The preparation of the fast-setting mortar for slope application of the present embodiment can be carried out using the same kneading equipment as that used for ordinary fast-setting mortar compositions, and is not particularly limited. Examples of the kneading equipment include a mortar mixer, a grout mixer, a hand mixer, a tilting mixer, and a twin-shaft mixer.

[0039] The fast-setting mortar for slope construction of this embodiment preferably has a 0-stroke flow value of 110-150 mm and a 15-stroke flow value of 160-260 mm, more preferably a 0-stroke flow value of 120-148 mm and a 15-stroke flow value of 180-250 mm, and even more preferably a 0-stroke flow value of 125-148 mm and a 15-stroke flow value of 195-245 mm. If the 0-stroke flow value is 110 or more and the 15-stroke flow value is 160 or more, pumping tends to be easy, and if the 0-stroke flow value is 150 mm or less and the 15-stroke flow value is 260 mm or less, the occurrence of material separation of the mortar is easily suppressed, and the fast-setting mortar for slope construction by trowel finishing tends to be easy to adjust.

[0040] The fast-setting mortar composition for sloped surface construction of this embodiment and the mortar thereof have a moderate fluidity that allows easy spreading while maintaining a moderate hardness, and are not easily separated, so that they can be applied to both large cross-sections by pumping and plastering with a trowel, and do not sag even on sloped surfaces. Therefore, the fast-setting mortar composition for sloped surface construction of this embodiment and the mortar thereof can be suitably used for repair, renovation, and construction work of sloped earthen floors, passageways, etc. The construction method is not particularly limited, and can be selected from a method of pumping to the construction site and finishing with a trowel, a method of filling the recesses with a trowel, a method of leveling with a vibrator after filling, and a method of finishing with a trowel. EXAMPLES

[0041] The present invention will be described in detail below with reference to examples, but the present invention is not limited thereto.

[0042] The materials used in the examples are as follows: Cement: Ordinary Portland cement Inorganic sulfate: anhydrous gypsum (Blaine specific surface area: 7000 cm 2 / g) Calcium aluminate: Alumina cement (main component: CA) Fine aggregate: Silica sand (adjusted to a coarse aggregate ratio of 2.0 to 3.0) Water reducing agent A: Naphthalene sulfonic acid water reducing agent Water reducing agent B: Melamine sulfonic acid water reducing agent Water reducing agent C: Lignosulfonic acid-based water reducing agent Water reducing agent D: Polycarboxylic acid-based high-performance water reducing agent Fiber: Nylon fiber (fiber length 5 mm) Hardening accelerator: sodium carbonate Set retarder: Citric acid Powder shrinkage reducing agents: alkylene oxide adducts of lower alcohols.

[0043] [Experimental Example 1] <Production of fast-hardening mortar composition> Each material was charged into a Henschel mixer in the proportions shown in Table 1 and mixed for 6 minutes to produce a fast-hardening mortar composition. In Table 1, the numerical values ​​of each material are shown in parts by mass when the binder consisting of cement, inorganic sulfate, and calcium aluminate is taken as 100 parts by mass.

[0044] <Production of fast-hardening mortar> The produced rapid hardening mortar composition and water were mixed for 90 seconds with a basket-type high-speed hand mixer (1000 rpm) to prepare a rapid hardening mortar. The mixing ratio of water is as shown in Table 1.

[0045] [Table 1]

[0046] <Evaluation of fresh properties of fast-hardening mortar> The produced fast-setting mortars (Products 1 to 7 of the present invention, and Reference Products 1 to 4) were evaluated for fresh consistency, pot life, material separation resistance, and workability. The evaluation test methods are shown below. [Consistency] The fast-hardening mortar was filled into a cement paste container (flow cone) according to JIS R5201:1997 "Physical Testing Methods for Cement," and the table flow value after the container was removed (0-stroke flow value) and the table flow value after 15 strokes of drop vibration (15-stroke flow value) were measured. In judging fluidity, in addition to being able to be pumped and filled, the fluidity was evaluated as being such that a gradient could be secured by trowel finishing after filling. If the flow value for 0 strokes was 110-150 mm and the flow value for 15 strokes was 160-260 mm, these were indicators of fluidity, and they were rated as "good." If they did not satisfy these criteria, they were rated as "poor." If separation was observed in the material separation resistance test described below, they were rated as "separated." [Pot life] 300ml of fast-setting mortar was placed in a 350ml plastic cup, and the plastic cup was replaced three times every 5 minutes to check the fluidity. The point at which the mortar gelled and lost its fluidity (the point at which the mortar would no longer fall out of the plastic cup when turned upside down) was taken as the pot life. The pot life was set as an index of whether the mixture could be maintained for 30 minutes or more after mixing, from the viewpoint of maintaining the workability required for pumping. [Material separation resistance] The resistance to material separation was evaluated by checking the presence or absence of aggregate separation in the mixed fast-hardening mortar by touch. If the fast-hardening mortar was not uniform and the feel of fine aggregate was clearly visible on the bottom of the container, it was rated as × (aggregate separation present), and if the fast-hardening mortar was uniform and the feel of fine aggregate was not noticeable on the bottom of the container, it was rated as ○ (no aggregate separation). [Workability] The fast-setting mortar was poured into a wooden formwork measuring 30cm in length, 30cm in width, and 15cm in height, and the fast-setting mortar was leveled with a trowel so that the gradient was approximately 2%. When the pot life was exhausted and the surface of the fast-setting mortar had begun to harden, the mortar was again leveled with the trowel to achieve a gradient of 2%. As an index of workability, a good trowel finish and gradient adjustment were given an O, and sagging or gradient adjustment was not possible were given an X.

[0047] Table 2 shows the evaluation results of fresh properties. The fast-setting mortars of the examples all had a zero-pump flow value of 129-146 mm and a 15-pump flow value of 187-240 mm immediately after mixing, confirming that they had fluidity that could be easily pumped. Regarding workability, the fast-setting mortar poured into the formwork could be easily leveled with a trowel and the gradient adjusted. Furthermore, it was confirmed that the pot life of each was 30 minutes or more.

[0048] [Table 2]

[0049] [Experimental Example 2] <Evaluation of hardening properties of mortar> The compressive strength of the hardened mortars (Products 1 to 7 of the present invention and Reference Products 1 and 2) was measured and evaluated. The evaluation test methods are as follows. [Compressive strength] Compressive strength was measured in accordance with JIS R5201:1997 "Physical Testing Methods for Cement". As an index of fast-hardening mortar, short-term strength was measured at ages of 3 hours and 24 hours. Curing was performed in air in a test room at 20℃ and RH 60% until each age.

[0050] The results of compressive strength measurements are shown in Table 3. The specimen in the example had a compressive strength of 12 N / mm at 3 hours. 2 It has a short-term strength development of 20N / mm at 24 hours. 2 The above strength development was confirmed.

[0051] [Table 3]

[0052] [Experimental Example 3] <Evaluation of pumpability and crack resistance of fast-hardening mortar> The pumpability and crack resistance of the fast-hardening mortar were confirmed using the present invention products 1, 3 and 4. The test method is as follows. [Pumpability] Using fast-setting mortar mixed in a pan mixer, it was pumped by a squeeze grout pump through a 20 m φ1.5 inch pressure hose, and the table flow value and material separation resistance of the fast-setting mortar emerging from the end of the hose were confirmed in the same manner as in Example 1. As an index of pumpability, a 0 shot flow value of the fast-setting mortar emerging from the end of the hose after pumping of 110 to 150 mm and a 15 shot flow value of 160 to 260 mm were evaluated as ◯ (good pumpability), and an outside of the range was evaluated as × (poor pumpability). [Crack resistance] In accordance with NEXCO Test Method 432-2006 "Test Method for Spray Mortar for Section Repair", fast-hardening mortar was poured into a triangular steel formwork (75mm x 75mm x 6mm x 1000mm) with D13 rebar welded to the bottom of the steel formwork, and the occurrence of cracks 28 days after molding was confirmed. Curing was carried out in a test room with a room temperature of 20±3℃ and a relative humidity of 60±10%.

[0053] Table 4 shows the evaluation results of pumpability and crack resistance of the fast-hardening mortar. The flow value after pumping of the product of the present invention was within the range of 139-145 mm for 0 shot flow value and 212-222 mm for 15 shot flow value, and good pumpability was confirmed without occurrence of blockage or material separation. In addition, no cracks were generated in the test specimens of the product of the present invention, and good crack resistance was confirmed.

[0054] [Table 4]

Claims

1. The concrete comprises cement, a binder made of inorganic sulfates and calcium aluminates, fine aggregate, a water-reducing agent, and fibers, The water-reducing agent includes at least one water-reducing agent selected from the group consisting of a naphthalene sulfonic acid-based water-reducing agent, a lignosulfonic acid-based water-reducing agent, and a melamine-based water-reducing agent, The content of the polycarboxylic acid-based water-reducing agent is less than 0.08 parts by mass per 100 parts by mass of the binder, The content of the cement is 55 to 78 parts by mass relative to 100 parts by mass of the binder, The content of the fine aggregate is 110 to 270 parts by mass relative to 100 parts by mass of the binder, The mass ratio of the inorganic sulfate to the calcium aluminates ([the content (parts by mass) of the calcium aluminate] / [the content (parts by mass) of the inorganic sulfate]) is 1.5 to 2. A fast-hardening mortar composition for application to sloped surfaces.

2. A fast-hardening mortar composition for use on inclined surfaces as described in claim 1, further containing a hardening accelerator.

3. A fast-hardening mortar composition for use on inclined surfaces as described in Claim 2, wherein the hardening accelerator is at least one selected from the group consisting of lithium carbonate, sodium carbonate and potassium carbonate.

4. A fast-hardening mortar composition for application on inclined surfaces as described in claim 2 or 3, wherein the content of the hardening accelerator is 0.1 to 2 parts by mass per 100 parts by mass of the binder.

5. The fast-hardening mortar composition for inclined surface construction according to any one of claims 1 to 4, wherein the content of the at least one water-reducing agent selected from the group consisting of naphthalene sulfonic acid-based water-reducing agents, lignin sulfonic acid-based water-reducing agents, and melamine-based water-reducing agents is 0.01 to 1 part by mass relative to 100 parts by mass of the binder.

6. The fast-hardening mortar composition for sloped surface construction according to any one of claims 1 to 5, further comprising a shrinkage reducing agent.

7. A method for constructing a sloping surface comprising the rapid-hardening mortar composition for sloped surfaces according to any one of claims 1 to 6 and water, The fast-hardening mortar for slope surface application, wherein the content of the water is 30 to 50 parts by mass per 100 parts by mass of the binder.