JP5776268B2 - Self-leveling material - Google Patents

Description

  The present invention relates to a self-leveling material used for construction of a structure such as a concrete floor structure. In particular, the present invention relates to a cement-based self-leveling material that provides a good cured surface finish even at low temperatures.

  The self-leveling material is required to have high fluidity, fluidity retention (pot life), fast curing, and the like. Moreover, in order to ensure surface accuracy, a good cured surface finish is required.

  Self-leveling materials can be broadly classified into gypsum and cement, and the latter is particularly problematic in changes in physical properties due to environmental temperature. Therefore, as a composition having excellent workability (high fluidity, long pot life) and curing characteristics (smoothness, dimensional stability, surface properties, strength development) in a wide temperature range, and having ultra-fast curability. Patent Document 1 discloses a self component comprising a hydraulic component made of alumina cement, Portland cement, gypsum and blast furnace slag, a setting rate adjusting agent made of a lithium salt and a boric acid compound, a water reducing agent, and a thickener. A flowable hydraulic composition is disclosed.

  In addition, as a composition that is excellent in high fluidity, horizontal level, surface finish, and curing characteristics in a low-temperature environment and does not generate cracks, Patent Document 2 includes a hydraulic component composed of alumina cement, Portland cement, and gypsum. A self-flowing hydraulic composition containing a setting accelerator and a fine aggregate, wherein the setting accelerator includes an aluminate (excluding a lithium salt) and a lithium salt is disclosed.

Japanese Patent No. 3697921 JP 2008-127250 A

  In the cement-based self-leveling material, alumina cement or Portland cement is mainly used as the hydraulic component, but it is desired to have a high Portland cement composition in terms of material cost and strength development. However, in this case, the surface properties after curing are easily affected by temperature, and surface cracks due to expansion are likely to occur particularly at low temperatures.

  The present invention provides a composition having a sufficiently high workability and curing characteristics, particularly a good cured surface finish even at low temperatures, in a self-leveling material containing Portland cement as a main component of a hydraulic component. For the purpose.

  In order to solve the above problems, the present inventors have changed the blending of the hydraulic component, the type and additive condition of the additive, the type of gypsum in the self-leveling material having Portland cement as the main component of the hydraulic component, As a result of examining the workability, the curing characteristics, and the temperature dependence of the cured surface finish in detail, it was found that the intended composition can be obtained by making these specific conditions, and the present invention was completed. .

  That is, the present invention comprises a hydraulic component comprising 40 to 60% by mass of Portland cement, 15 to 40% by mass of alumina cement and 10 to 30% by mass of gypsum, an inorganic powder, a fine aggregate, a fluidizing agent, A self-leveling material comprising a setting modifier, wherein the gypsum contains α-half-water gypsum, and the content of α-half-water gypsum in the hydraulic component is 2 to 20% by mass. Such a self-leveling material has sufficiently high workability and curing characteristics, and in particular, a good cured surface finish can be obtained even at low temperatures.

  The self-leveling material of the present invention contains 35 to 200 parts by mass of inorganic powder and 85 to 325 parts by mass of fine aggregate with respect to 100 parts by mass of the hydraulic component contained in the composition. An effect can be expressed more reliably.

  Moreover, it is preferable that the said inorganic powder is a blast furnace slag fine powder and / or a limestone fine powder from a viewpoint of improving the intensity | strength development property and dimensional stability of a self-leveling material.

  According to the present invention, it is cheaper than a self-leveling material having a conventional alumina cement as a main component of a hydraulic component, is excellent in strength development, has sufficiently high workability (high fluidity, long pot life) and curing characteristics ( In particular, a self-leveling material having smoothness and dimensional stability) and having a good cured surface finish even at low temperatures can be provided.

  The present invention is described in detail below.

  The self-leveling material of the present invention comprises a hydraulic component comprising 40 to 60% by mass of Portland cement, 15 to 40% by mass of alumina cement and 10 to 30% by mass of gypsum, an inorganic powder, a fine aggregate, and a fluidizing agent. And a setting modifier.

  Here, the Portland cement used for the hydraulic component may be selected from ordinary Portland cement, early-strength Portland cement, ultra-high strength Portland cement, moderately hot Portland cement, low heat Portland cement and sulfate resistant Portland cement. it can. Moreover, mixed cements such as blast furnace cement, fly ash cement, silica cement and the like can be used as an alternative. From the viewpoint of quick setting, it is preferable to use ordinary Portland cement, early-strength Portland cement, or ultra-early-strength Portland cement.

  Several types of alumina cements having different mineral compositions are known and are commercially available as hydraulic components. All of these commercially available products are mainly composed of monocalcium aluminate (CA), and any commercially available product can be used regardless of its type.

  The gypsum used for the hydraulic component contains α hemihydrate gypsum, and the content of α hemihydrate gypsum in the hydraulic component is 2 to 20% by mass. When the content of α hemihydrate gypsum is less than 2% by mass, a good cured surface finish tends not to be obtained. Moreover, when the content of α hemihydrate gypsum exceeds 20% by mass, the fluidity tends to decrease. A preferable content rate is 2 to 17% by mass, more preferably 3 to 15% by mass, and still more preferably 3 to 10% by mass.

  Examples of the gypsum component other than α hemihydrate gypsum include dihydrate gypsum, β hemihydrate gypsum, and anhydrous gypsum, and gypsum produced as a by-product in flue gas desulfurization and hydrofluoric acid production processes, or naturally produced. Any gypsum can be used. From the viewpoint of workability (high fluidity, long pot life), it is preferable to use anhydrous gypsum.

  In the self-leveling material according to the present invention, a favorable cured surface finish can be obtained even at low temperatures by blending a predetermined amount of α-hemihydrate gypsum. On the other hand, it is difficult to obtain this effect with β hemihydrate gypsum. The reason why such a specific effect is obtained is not necessarily clear, but by blending a predetermined amount of α hemihydrate gypsum, an ettringite film with an appropriate thickness is formed on the particle surface of Portland cement, and coexisting alumina The present inventors presume that the reaction with cement or gypsum has the effect of keeping the reaction constant regardless of the temperature. On the other hand, in β hemihydrate gypsum and other gypsum, the formation of the film becomes insufficient, and the temperature dependence of the reaction appears to be large, and it is assumed that fine ettringite that is expandable at low temperatures is generated, causing surface cracks. Is done.

  In the present invention, as a hydraulic component, by using a hydraulic component composed of Portland cement, alumina cement and gypsum, it has excellent self-fluidity, and has a proper pot life and excellent fast-curing property. A leveling material can be obtained.

  The hydraulic component needs to include Portland cement, alumina cement, and gypsum in the above range when the mass is 100% by mass. This makes it easy to obtain a cured product that is low in material cost, has self-fluidity and rapid curing, and has a small volume change during curing.

  The blending ratio of the hydraulic component is preferably Portland cement 42 to 58 mass%, alumina cement 20 to 36 mass% and gypsum 14 to 30 mass%, more preferably Portland cement 45 to 55 mass%, alumina cement 23 to 33 mass% and gypsum 17-27 mass%, particularly preferably Portland cement 47-53 mass%, alumina cement 25-29 mass% and gypsum 19-25 mass%.

  As the inorganic powder, blast furnace slag fine powder specified by JIS A 6206 “Blast furnace slag fine powder for concrete”, siliceous mixed material specified by JIS R 5212 “silica cement”, JIS A 6207 “silica fume for concrete” Silica fume specified in JIS A 6201 “Fly ash for concrete”, fine limestone powder, and the like can be used. Here, the limestone fine powder can be suitably used by pulverizing limestone, but if it is an inorganic powdery substance mainly composed of calcium carbonate, it is obtained by pulverizing waste concrete or the like and chemically purified. Calcium carbonate or the like can be substituted. Among these, strength development and dimensional stability can be improved by using blast furnace slag fine powder and / or limestone fine powder as the inorganic powder.

Further, these inorganic powders is preferably Blaine specific surface area measured in accordance with JIS R 5201 "Physical testing methods for cement" is 3000 cm ² / g or more, more preferably 3000~8000cm ² / g More preferably, it is 3200-5200 cm < ² > / g.

  Fine aggregates according to the present invention include silica sand, river sand, land sand, sea sand, crushed sand and other sand, slag fine aggregate, recycled fine aggregate, waste FCC catalyst, quartz powder, alumina clinker, urethane crushed, It can be appropriately selected from resin pulverized products such as EVA foam and foaming resin. In particular, sand selected from quartz sand, river sand, land sand, sea sand, crushed sand, waste FCC catalyst, quartz powder and alumina clinker can be suitably used.

  The fine aggregate preferably contains less than 5% by mass of coarse particles having a particle diameter of 600 μm or more in 100% by mass and has a water absorption of 1.6% or less in terms of fluidity. Here, 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, “the coarse particle portion having a particle diameter of 600 μm or more” means the mass ratio of the remaining particles when a 600 μm sieve is used. Further, the water absorption rate of the fine aggregate is a value measured according to the method of measuring the water absorption rate (unit:%) of the aggregate defined in JIS A 1109: 2006.

  In order to obtain excellent self-fluidity, the coarse particle content in the fine bone agent is preferably 0 to 3% by mass, more preferably 0 to 0.5% by mass, still more preferably 0 to 0.2% by mass, and 01-0.15 mass% is especially preferable. The water absorption of the fine bone agent is preferably 0 to 1.50%, more preferably 0 to 1.40%, still more preferably 0 to 1.30%, and particularly preferably 0.1 to 1.28%.

  In addition, the coarse particle ratio of the fine aggregate is in the range of 1.00 to 1.40, the unit volume mass of the fine aggregate is in the range of 1.45 to 1.70 kg / L, and the fine aggregate performance rate Is desirably in the range of 55.0 to 61.0%. Thereby, more excellent self-fluidity can be obtained.

  Here, the “rough grain ratio” refers to the coarse grain ratio of the aggregate as defined in JIS A 1102: 2006. The “unit volume mass” refers to the unit volume mass (unit: kg / L) of the aggregate as defined in JIS A 1104: 2006. The “actual rate” refers to the actual rate (unit:%) of the aggregate defined in JIS A 1104: 2006.

  The coarse particle ratio of the fine aggregate is preferably 1.00 to 1.40, more preferably 1.10 to 1.35, still more preferably 1.11 to 1.32, and particularly preferably. 1.12 to 1.30. The unit volume mass of the fine aggregate is preferably 1.45 to 1.70 kg / L, more preferably 1.50 to 1.60 kg / L, still more preferably 1.51 to 1.57 kg. / L, particularly preferably 1.52 to 1.55 kg / L. Moreover, as a performance rate of a fine aggregate, Preferably it is 55.0-61.0%, More preferably, it is 56.0-60.0%, More preferably, it is 56.5-59.5%. Especially preferably, it is 57.0 to 59.0%.

  The self-leveling material of the present invention preferably contains 35 to 200 parts by mass of inorganic powder and 85 to 325 parts by mass of fine aggregate with respect to 100 parts by mass of the hydraulic component. Thereby, workability | operativity and hardening characteristics can be improved more.

  The content ratio of the inorganic powder is more preferably 40 to 180 parts by mass, further preferably 60 to 150 parts by mass, and 70 to 130 parts by mass with respect to 100 parts by mass of the hydraulic component. Particularly preferred. The content ratio of the fine aggregate is more preferably 100 to 300 parts by mass with respect to 100 parts by mass of the hydraulic component, further preferably 150 to 275 parts by mass, and 165 to 250 parts by mass. Particularly preferred.

  The self-leveling material is usually used with a small amount of mixing water in order to obtain a high-strength cured body while suppressing material separation. Therefore, in the self-leveling material of the present invention, a fluidizing agent having a water reducing effect is an essential component in order to ensure high fluidity even if the water / hydraulic component ratio is small.

  As the fluidizing agent, commercially available fluidizing agents such as formaldehyde condensate of melamine sulfonic acid, casein, casein calcium, polycarboxylic acid, polyether and polyether polycarboxylic acid, which have a water reducing effect, are included. It can be used regardless of the type, and it is particularly preferable to use a commercially available fluidizing agent such as polyether-based and polyether polycarboxylic acid.

  The fluidizing agent can be appropriately added in a range that does not impair the characteristics, depending on the hydraulic component used, and is preferably 0.01 to 2.0 parts by mass, more preferably 100 parts by mass with respect to the hydraulic component. 0.05 to 1.0 part by mass, more preferably 0.07 to 0.7 part by mass, and particularly preferably 0.1 to 0.5 part by mass. If the addition amount of the fluidizing agent is too small, a suitable effect (excellent fluidity and high cured body strength) will not be exhibited. Not only is it economical, but in some cases the viscosity becomes large and the amount of kneading water for obtaining the required fluidity increases, which may deteriorate the strength properties.

  The self-leveling material of the present invention contains a setting modifier as an essential component in order to adjust the pot life (fluid retention) and fast curing. There are accelerators and retarders as setting modifiers, and these components and addition amounts are appropriately selected according to the formulation of the hydraulic component to be used.

  A well-known thing can be used as a setting retarder contained in the self-leveling material of this invention. For example, organic acids such as oxycarboxylic acids, sugars such as glucose, maltose, dextrin, sodium bicarbonate, sodium phosphate, etc. may be used alone or in combination of two or more components. it can.

  Oxycarboxylic acids include oxycarboxylic acids and their salts. Examples of oxycarboxylic acid include citric acid, gluconic acid, tartaric acid, glycolic acid, lactic acid, hydroacrylic acid, α-oxybutyric acid, glyceric acid, tartronic acid, malic acid and other aliphatic oxyacids, salicylic acid, m-oxy Mention may be made of aromatic oxyacids such as benzoic acid, p-oxybenzoic acid, gallic acid, mandelic acid and tropic acid.

  Examples of the salt of oxycarboxylic acid include alkali metal salts (specifically sodium salt and potassium salt) and alkaline earth metal salts (specifically calcium salt, barium salt and magnesium salt). Sodium salts are more preferred. In particular, sodium tartrate is preferred from the standpoint of setting delay effect, availability, and price, and more preferably used in combination with sodium bicarbonate.

  The setting retarder is preferably 0.01 to 2 parts by weight, more preferably 0.1 to 1.5 parts by weight, and still more preferably 0.2 to 1.2 parts, with respect to 100 parts by weight of the hydraulic component. The use time (handling time) by which suitable fluidity | liquidity is acquired can be ensured by using in the range of a mass part, Especially preferably 0.2-1 mass part. Furthermore, by adjusting the addition amount of the setting retarder to the above preferable range, a mortar having self-fluidity (self-leveling property) and having a pot life (handling time) capable of obtaining suitable fluidity is obtained. be able to.

  As the setting accelerator contained in the self-leveling material of the present invention, a known component for promoting setting can be used. For example, lithium salt, aluminum sulfate, and calcium chloride having a setting acceleration effect can be preferably used, and several of these can be used in combination.

  Examples of lithium salts include inorganic lithium salts such as lithium carbonate, lithium chloride, lithium sulfate, lithium nitrate and lithium hydroxide, and organic acid organics such as lithium oxalate, lithium acetate, lithium tartrate, lithium malate and lithium citrate. A lithium salt can be mentioned. In particular, lithium carbonate is preferable from the viewpoint of the setting acceleration effect, availability, and cost.

  As the setting accelerator, those having a particle size that does not interfere with the properties of the self-leveling material are preferably used, and the particle size is preferably 50 μm or less. Particularly when a lithium salt is used, the particle diameter of the lithium salt is preferably 50 μm or less, more preferably 30 μm or less, still more preferably 20 μm or less, and particularly preferably 10 μm or less. When the particle diameter of the lithium salt is larger than the above range, the solubility of the lithium salt becomes small, which is not preferable. In particular, in the pigment addition system, it is noticeable as a large number of fine spots, and the appearance may be impaired.

  The setting accelerator is preferably 0.01 to 1 part by weight, more preferably 0.01 to 0.5 part by weight, and still more preferably 0.02 to 0.4 part with respect to 100 parts by weight of the hydraulic component. By using it in a mass part, particularly preferably in the range of 0.04 to 0.3 part by mass, it is preferable because a suitable quick hardening can be obtained after securing the pot life of the self-leveling material. By adjusting the addition amount of the setting accelerator within the above-mentioned preferable range, a mortar having self-fluidity (self-leveling property) and securing a good pot life is obtained, and a suitable fast-curing property is obtained. Can do.

  In addition to the above essential components, a thickener, an antifoaming agent, a shrinkage reducing agent, a resin powder, and the like can be added to the self-leveling material of the present invention as necessary.

  The self-leveling material of the present invention has sufficiently high workability (high fluidity, long pot life) and curing characteristics (smoothness, dimensional stability). The self-leveling material of the present invention takes advantage of these characteristics as a leveling material, such as schools, condominiums, convenience stores, hospitals, verandas, factories, warehouses, parking lots, gas stations, kitchens, and rooftops, and floor finishes. Can be used for materials. In addition, since the self-leveling material of the present invention can obtain a good cured surface finish even at low temperatures, it can be stably used for these applications regardless of the season or region.

  The contents of the present invention will be specifically described below with reference to examples. Note that the present invention is not limited to these examples.

[Materials used]
The materials used in Examples and Comparative Examples are described below.

(1) Hydraulic component Portland cement [PC] (early strength Portland cement, manufactured by Ube Mitsubishi Cement Co., Ltd., Blaine specific surface area 4500 cm ² / g)
Alumina cement [AC] (Fonju, Kerneos, Blaine specific surface area 3100 cm ² / g)
Gypsum [GG] (Natural anhydrous gypsum, α hemihydrate gypsum, β hemihydrate gypsum)

The said material was mix | blended in the ratio shown in Table 1, and the hydraulic component was prepared.

(2) Inorganic powder Blast furnace slag fine powder [BFS] (Reverment, manufactured by Chiba Riverment Co., Ltd., Blaine specific surface area 4400 cm ² / g)
(3) Fine aggregate Silica sand [S] (coarse fraction having a particle diameter of 600 μm or more = 0.1 mass%, water absorption = 1.25%, coarse grain ratio 1.15, unit volume mass = 1.53 kg / L, actual rate = 57.5%)
(4) Fluidizing agent Polycarboxylic acid based fluidizing agent (Kao Corporation)
(5) Setting retarder Na tartrate (manufactured by Fuso Chemical Industries)
(6) Setting accelerator Lithium carbonate (Honjo Chemical Co., Ltd.)

[Preparation of mortar]
The above materials (total amount: 1.5 kg) were mixed at a blending ratio shown in Table 2, and kneaded using a chemistor to prepare a self-leveling material. Next, 390 g of water was added to the obtained self-leveling material and kneaded for 3 minutes to obtain a mortar. The mortar was prepared in a thermostatic chamber at a temperature of 5 ° C.

[Evaluation of cured surface finish]
The prepared mortar was poured into a 13 cm × 19 cm resin mold at a thickness of 10 mm, and the surface finish at each age was visually observed to confirm the presence or absence of cracks. Evaluation was performed in a constant temperature room at a temperature of 5 ° C. The evaluation results are shown in Table 2.

  As shown in Examples 1 and 2 in Table 2, the self-leveling material of the present invention using a predetermined amount of α hemihydrate gypsum did not show cracks on the surface of the cured product. On the other hand, as shown in Comparative Examples 1 to 3, in the case of a mortar using only natural anhydrous gypsum as a gypsum in a hydraulic component or a mortar added with β hemihydrate gypsum, the cured material can be obtained at a material age of 2 days or 3 days. Cracks occurred on the surface. It has been confirmed that this crack does not occur in an environment of 20 ° C. and is independent of the Shore hardness.

  Based on the above results, in the self-leveling material that uses Portland cement, which is easily affected by environmental temperature, as the main component of the hydraulic component, the hydraulic component should be blended properly and a certain amount of α hemihydrate gypsum should be used. Thus, it was confirmed that a self-leveling material having sufficiently high workability and curing characteristics and having a satisfactory cured surface finish even at low temperatures can be obtained. The self-leveling material of the present invention is cheaper and more excellent in strength than conventional self-leveling materials containing alumina cement as the main component of the hydraulic component, and can be used for a wide range of applications.

Claims (3)

Portland cement 40-60% by mass, alumina cement 15-40% by mass and gypsum 10-30% by mass hydraulic component, inorganic powder, fine aggregate, fluidizing agent, setting agent, Containing self-leveling material,
The gypsum includes α hemihydrate gypsum and anhydrous gypsum , and the content of the α hemihydrate gypsum in the hydraulic component is 2 to 20% by mass.   The self-leveling material according to claim 1, comprising 35 to 200 parts by mass of the inorganic powder and 85 to 325 parts by mass of the fine aggregate with respect to 100 parts by mass of the hydraulic component.   The self-leveling material according to claim 1 or 2, wherein the inorganic powder is blast furnace slag fine powder and / or limestone fine powder.