JP7034573B2 - Fast-curing polymer cement composition and fast-curing polymer cement mortar - Google Patents

Description

The present invention relates to a fast-curing polymer cement composition and a fast-curing polymer cement mortar.

Polymer cement mortar, which is a mixture of mortar and various polymers, is used for the purpose of solving problems related to dry shrinkage, chemical resistance, strength, etc. caused by cement hydrate for problems such as cracking and peeling of concrete structures. Widely used as a construction material. However, with conventional polymer cement mortars, it takes a long time for the cement to harden, and this tendency is more remarkable especially at low temperatures. Therefore, the conventional polymer cement mortar is not always sufficient for on-site construction.

In response to this situation, in recent years, in order to accelerate the curing of cement, a polymer cement mortar using a fast-curing cement having a high curing rate has been proposed (for example, Patent Document 1).

Japanese Unexamined Patent Publication No. 2013-234489

By the way, since the polymer cement mortar is used as a repair / reinforcing material, it is required to achieve both good fluidity and compressive strength as well as a curing speed. When the compressive strength of the polymer cement is further increased, the cement hardened body is densified by reducing the water-cement ratio. However, when the water-cement ratio is reduced, the fluidity tends to deteriorate, and it is difficult to achieve both good fluidity and compressive strength.

It is an object of the present invention to provide a fast-curing polymer cement composition and a fast-curing polymer cement mortar which are excellent in fluidity and also excellent in initial strength development and strength development after the initial stage.

As a result of diligent studies on the above problems, the present inventors have combined quick-hardening cement, gypsum and quicklime, and further blended a specific amount of fine aggregate having a specific particle size to achieve good fluidity and strength development. It was found that both can be achieved. That is, the present invention is, for example, the following fast-curing polymer cement compositions and quick-hardening polymer cement mortars [1] to [6].
[1] Fast-curing cement, gypsum, fresh lime, polymer for cement, fine aggregate A having a particle size of 0.6 mm or more and fine aggregate B having a particle size of 0.09 mm or more and less than 0.3 mm. A fast-curing polymer cement composition containing fine aggregate and a mass ratio of plaster and fresh lime ([mass of plaster] / [mass of fresh lime]) of 1.1 or more, and fine aggregate. The total content of A and the fine aggregate B is 75 parts by mass or more with the total mass of the fine aggregate as 100 parts by mass, and the mass ratio of the fine aggregate A and the fine aggregate B ([[fine aggregate A] A composition having a mass] / [mass of fine aggregate B]) of 1.8 to 2.5 .
[2] The composition according to [1], wherein the total content of gypsum and quicklime is 2.5 to 20 parts by mass, with the total mass of gypsum and quicklime as 100 parts by mass. ..
[3] The composition according to [1] or [2], wherein the mass ratio of gypsum and quicklime is 1.8 to 4.
[4] Of [1] to [3], the total mass of fast-curing cement, gypsum and quicklime is 100 parts by mass, the polymer for cement is 10 to 50 parts by mass, and the fine aggregate is 200 to 350 parts by mass. The composition according to any.
[5] The composition according to any one of [1] to [4], further comprising a water reducing agent.
[6] The composition according to any one of [1] to [5] and water are contained, and the total mass of fast-curing cement, gypsum and quicklime is 100 parts by mass, and 20 to 45 mass of water is used. Fast-curing polymer cement mortar, including gypsum.

According to the present invention, it is possible to provide a fast-curing polymer cement composition and a fast-curing polymer cement mortar which are excellent in fluidity and also excellent in initial strength development and strength development after the initial stage.

Hereinafter, embodiments of the present invention will be described in detail, but the present invention is not limited thereto.

The fast-curing polymer cement composition of the present embodiment includes fast-hardening cement, gypsum, quicklime, a polymer for cement, a fine aggregate A having a particle size of 0.6 mm or more, and a particle size of 0.09 mm or more. Includes fine aggregate, including fine aggregate B that is less than 3 mm.

The fast-curing cement preferably contains calcium sulfates as an active ingredient, and contains 11CaO / 7Al _{2O 3} / CaX ₂ (X indicates a halogen atom) or 3CaO / 3Al ₂ O ₃ / CaSO ₄ (auyne). Those contained as an active ingredient are more preferable. _11CaO・ 7Al _2O3・ CaX ₂ is a so-called calcium aluminate halide-based cement. The halogen atom is preferably a fluorine atom. Hauyne is also referred to as calcium sulfoluminate-based cement (auyne-based cement). These are called ultrafast hard cements and are commercially available under the trade name Jet Cement or Super Jet Cement. Hauyne cement is the most preferable as the quick-hardening cement.
As calcium aluminates, when CaO is indicated by C, Al ₂ O ₃ is indicated by A, and Fe ₂ O ₃ is indicated by F, C ₃ A, C ₂ A, C ₁₂ A ₇ , C ₅ A ₃ , CA, C ₃ A ₅ or CA ₂ etc. Calcium aluminate having a mineral composition, C ₂ AF, C ₄ AF etc. Calcium aluminoferrite, alumina cement, and SiO ₂ , K ₂ thereof. Includes solid-dissolved or compounded O, Fe ₂ O ₃ , TiO ₂ , and the like. The calcium aluminates may be crystalline or amorphous. As the quick-hardening cement, a quick-hardening admixture prepared by blending these calcium aluminates and inorganic salts such as gypsum may be added to Portland cement. As the quick-hardening cement, one type may be used alone, or two or more types may be used in combination.

The fast-hardening cement may be one in which a part of the quick-hardening cement is replaced with Portland cement. As the Portland cement, ordinary Portland cement, early-strength Portland cement, ultra-early-strength Portland cement, moderate heat Portland cement, low heat Portland cement and the like can be used. The content of Portland cement is preferably 20 parts by mass or less, preferably 10 parts by mass or less, based on 100 parts by mass of fast-hardening cement, from the viewpoint of ensuring better pot life, developing early strength, and durability against repeated loading. Is more preferable.

The gypsum is not particularly limited, and examples thereof include anhydrous gypsum, hemihydrate gypsum, and dihydrate gypsum. Further, the gypsum is not particularly limited in the raw material history, and may be, for example, various chemical gypsum. As the gypsum, type II anhydrous gypsum may be used from the viewpoint that the strength development in the medium to long term is more likely to be enhanced. As the gypsum, one type may be used alone, or two or more types may be used in combination. The particle size of the gypsum is not particularly limited, but the brain specific surface area is preferably 3000 to 10000 cm ² / g from the viewpoint of obtaining a reaction activity that is easier to control.

The quicklime is not particularly limited as long as it has a hydration reaction activity, and may be any quicklime. The quicklime according to the present embodiment may be a simple substance of calcium oxide or a calcined quicklime product containing free calcium oxide as a main component. Examples of quick lime include quick lime such as soft-baked quick lime, medium-baked quick lime, hard-baked quick lime, and extremely hard-baked quick lime. As the quicklime, one kind may be used alone, or two or more kinds may be used in combination. The particle size of quicklime is not particularly limited, but the brain specific surface area is preferably 2000 to 6000 cm ² / g from the viewpoint of obtaining a reaction activity that is easier to control.

The total content of gypsum and quicklime is 2.5 to 20 parts by mass, with the total mass of fast-hardening cement, gypsum and quicklime as 100 parts by mass, from the viewpoint of obtaining better initial strength development. Is preferable, 5 to 15 parts by mass is more preferable, and 5 to 10 parts by mass is further preferable.

The mass ratio of gypsum and quicklime ([mass of gypsum] / [mass of quicklime]) is 1.1 or more, preferably 20 or less. The mass ratio of gypsum and quicklime is, for example, preferably 1.1 to 15, more preferably 1.5 to 5, further preferably 1.8 to 4, and particularly preferably 1.8 to 3.5. When the mass ratio of gypsum and quicklime is within the above range, good fluidity can be easily ensured, and the strength development from the initial stage is further excellent.

The polymer for cement is preferably the polymer specified in JIS A 6203: 2015 “Polymer dispersion for cement admixture and re-emulsified powder resin”. Examples of such a polymer for cement include polymer dispersions and re-emulsified powder resins. Examples of the polymer dispersion include synthetic rubber type such as styrene-butadiene rubber; natural rubber type; rubber asphalt type; ethylene vinyl acetate type; acrylic acid ester type; resin asphalt type and the like. Among the polymer dispersions, synthetic rubber-based, ethylene-vinyl acetate-based and acrylic acid ester-based are preferable, and specifically, synthetic rubber latex, polyacrylic acid ester and ethylene vinyl acetate are more preferable. Examples of the re-emulsified powder resin include synthetic rubber such as styrene-butadiene rubber; acrylic acid ester type; ethylene vinyl acetate type; vinyl acetate / versatic acid vinyl ester; vinyl acetate / versatic acid vinyl / acrylic acid ester and the like. As the polymer for cement, a polymer dispersion may be used, a re-emulsified powder resin may be used, or the polymer dispersion and the re-emulsified powder resin may be used in combination.
Among the above-mentioned polymers for cement, polymer dispersion of styrene-butadiene rubber and / or re-emulsified powder resin is preferable from the viewpoint of further improving the adhesiveness to concrete. Styrene-butadiene rubber is a kind of synthetic rubber obtained by copolymerizing styrene and butadiene, and its quality can be appropriately adjusted depending on the styrene content and the vulcanization amount. For cement admixture, the amount of bonded styrene is often 50 to 70% by mass, and it is used with improved stability and adhesiveness. As the cement polymer, one type may be used alone, or two or more types may be used in combination.

The content of the cement polymer is preferably 10 to 50 parts by mass, more preferably 10 to 40 parts by mass, and 10 to 35 parts by mass, with the total mass of the fast-curing cement, plasters and quicklime as 100 parts by mass. By mass is even more preferred, 12.5 to 30 parts by mass is even more preferred, and 15 to 25 parts by mass is particularly preferred. When the content of the polymer for cement is within the above range, it is easy to secure sufficient adhesion strength with concrete, and the strength development tends to be difficult to decrease.

Examples of the fine aggregate include river sand, silica sand, crushed sand, cold water stone, limestone sand, and slag aggregate. Among these fine aggregates, it is preferable to use fine aggregates such as silica sand and limestone sand whose particle size is adjusted so as not to contain fine powder or coarse aggregate. The fine aggregate is a commonly used material having a particle size of less than 5 mm (passing through a 5 mm sieve). As the fine aggregate, one type may be used alone, or two or more types may be used in combination.

The fast-curing polymer cement composition of the present embodiment contains a fine aggregate A having a particle size of 0.6 mm or more and a fine aggregate B having a particle size of 0.09 mm or more and less than 0.3 mm. The particle size of the fine aggregate A is preferably less than 5 mm. The fine aggregate A passes through a sieve with an opening of 5 mm and stays in the sieve with an opening of 0.6 mm, and the fine aggregate B passes through a sieve with an opening of 0.3 mm and has an opening of 0.09 mm. It stays on the sieve.

The total content of the fine aggregate A and the fine aggregate B is 50 parts by mass or more, preferably 75 parts by mass or more, and more preferably 80 parts by mass or more, with the total mass of the fine aggregate as 100 parts by mass. The upper limit of the total content of the fine aggregate A and the fine aggregate B may be 100 parts by mass or 90 parts by mass or less, assuming that the total mass of the fine aggregate is 100 parts by mass. When the total content of the fine aggregate A and the fine aggregate B is within the above range, it is easy to secure better fluidity.

The mass ratio of the fine aggregate A and the fine aggregate B ([mass of the fine aggregate A] / [mass of the fine aggregate B]) is 1.5 to 5, preferably 1.5 to 3, and 1 .8 to 2.5 is more preferable. When the mass ratio of the fine aggregate A and the fine aggregate B is within the above range, it is easy to secure better fluidity and long-term strength development.

The content of the fine aggregate is preferably 200 to 350 parts by mass, more preferably 225 to 325 parts by mass, and further 25 to 310 parts by mass, with the total mass of the fast-curing cement, gypsum and quicklime as 100 parts by mass. preferable. When the content of the fine aggregate is within the above range, it is easy to secure the pot life and it is easy to obtain better strength development.

The fast-curing polymer cement composition of the present embodiment may contain a water reducing agent. Water reducing agents include high performance water reducing agents, high performance AE water reducing agents, AE water reducing agents and fluidizing agents. Examples of such a water reducing agent include water reducing agents specified in JIS A 6204: 2011 “Chemical admixture for concrete”. Examples of the water reducing agent include a polycarboxylic acid-based water reducing agent, a naphthalene sulfonic acid-based water reducing agent, a lignin sulfonic acid-based water reducing agent, a melamine-based water reducing agent, and an acrylic water-reducing agent. Among these, a naphthalene sulfonic acid-based water reducing agent is preferable. As the water reducing agent, one type may be used alone, or two or more types may be used in combination.

The content of the water reducing agent is 0.5 to 5 parts by mass, with the total mass of the fast-curing cement, gypsum and quicklime as 100 parts by mass, from the viewpoint that it is easy to secure fluidity and the initial strength development is further excellent. Is preferable, and 1 to 3.5 parts by mass is more preferable.

The fast-curing polymer cement composition of the present embodiment may contain a setting retarder. By including the setting retarder, it is easy to secure the pot life even when the kneading temperature of the polymer cement mortar becomes high such as in summer. Examples of the setting retarder include organic acids such as citric acid, gluconic acid, malic acid and tartrate or salts thereof; borates such as boric acid and sodium borate, phosphates, alkali metal carbonates and alkali metal weights. Inorganic salts such as carbonates; saccharides and the like. Among these, citric acid, citrate, tartaric acid, tartaric acid, and alkali metal carbonate are preferable. The setting retarder may be a powder or a liquid (for example, in the form of an aqueous solution, an emulsion or a suspension). As the condensation retarder, one type may be used alone, or two or more types may be used in combination.

The content of the setting retarder shall be 0.5 to 5 parts by mass, with the total mass of fast-curing cement, gypsum and quicklime as 100 parts by mass in terms of the active ingredient (solid component) in the setting retarder. It is preferably 1 to 3 parts by mass, and more preferably 1 to 3 parts by mass. When the content of the setting retarder is within the above range, it is easy to secure the pot life and the initial strength development is unlikely to decrease.

In the fast-curing polymer cement composition of the present embodiment, various admixtures may be used as long as the effects of the present invention are not impaired. Examples of the admixture include defoaming agents, waterproofing agents, rust preventives, shrinkage reducing agents, thickeners, water retention agents, pigments, water repellents, efflorescence inhibitors, and fibers.

The fast-curing polymer cement composition of the present embodiment can also be made into a concrete composition by using a coarse aggregate. Examples of the coarse aggregate include river gravel, land gravel, crushed stone, artificial coarse aggregate, slag coarse aggregate, and recycled coarse aggregate. The coarse aggregate has a particle size of 5 mm or more (5 mm sieve residue), and is preferably 25 mm or less. The content of the coarse aggregate can be appropriately set within the range of the amount usually used for preparing concrete.

The fast-curing polymer cement composition of the present embodiment can be prepared by mixing with a kneading device usually used, and the device is not particularly limited. Examples of the kneading device include a hobert mixer, a hand mixer, a tilting mixer, a twin-screw mixer, and the like.

The fast-curing polymer cement composition of the present embodiment can be mixed with water to prepare a mortar or concrete, and the water content thereof may be appropriately adjusted according to the intended use. The water content is preferably 20 to 50 parts by mass, more preferably 22.5 to 40 parts by mass, and further 25 to 40 parts by mass, with the total mass of the fast-curing cement, gypsum and quicklime as 100 parts by mass. preferable. When the water content is within the above range, it is easier to secure fluidity, and it is easy to suppress the occurrence of material separation, the increase in shrinkage of the cured product, and the decrease in the initial strength development.

The preparation of the fast-curing polymer cement mortar of the present embodiment can use the same kneading equipment as the ordinary polymer cement mortar, and is not particularly limited. As the kneading tool, for example, the above-mentioned one can be used.

The fast-curing polymer cement composition of the present embodiment and the fast-curing polymer cement mortar using the same have good fluidity, excellent initial strength development, and stable strength even after the initial stage. Since it can exhibit its expressiveness, it is excellent in workability and durability. Further, since the fast-curing polymer cement composition of the present embodiment and the fast-curing polymer cement mortar using the fast-curing polymer cement mortar use the fast-curing cement, the curing speed is high and the working time can be shortened. Therefore, such a fast-curing polymer cement composition and a fast-curing polymer cement mortar using the same can be used, for example, as a repair / reinforcing material for concrete structures, roads, and the like.

Hereinafter, the present invention will be described in detail with reference to Examples, but the present invention is not limited thereto.

Table 1 shows the materials used, and Table 2 shows the fine aggregates whose particle size has been adjusted. The fine aggregate was adjusted to each particle size distribution by sieving using various sieves.

[Mixing design]
The total mass of quick-hardening cement, gypsum, and quicklime is 100 parts by mass, and quicklime, gypsum, and fine aggregate are blended and designed as shown in Table 3, and a water reducing agent and a setting retarder are added by 1 part by mass. And prepared. Various polymer cement mortars were prepared by adding the above powder to a cement polymer (in terms of solid content) prepared with the amount of water shown in Table 3 and kneading with a hand mixer for 90 seconds.

[Evaluation methods]
-Consistency The fluidity of the polymer cement mortar was evaluated by measuring the consistency. The consistency is described in JIS R 5201: 2015 [“Physical test method for cement” 12. Flow test] was measured in an environment of 20 ° C. As for the consistency, those having a 15-stroke flow / drawing flow of 1.35 or more were evaluated as good (◯), and those having a consistency of less than 1.35 were evaluated as defective (x).

-Compressive strength The strength development of the polymer cement mortar was evaluated by measuring the compressive strength of the cured product. The compressive strength was measured at 2 hours and 28 days of age according to the JSCE standard JSCE-G 505-2010 "Compressive strength test method for mortar or cement paste using a cylindrical specimen (draft)". .. The dimensions of the specimen were 50 mm in diameter and 100 mm in height. In addition, the curing was first performed in a constant temperature bath at 20 ° C., demolded the next day, and then cured in the air at 20 ° C. until the age of the material. It was judged that the strength development was good if the material age was 10 N / mm ^{2 or more at 2 hours and 45 N / mm 2 or} more at 28 days.

[result]
The results of each test are shown in Table 4. It was shown that the polymer cement mortar of the example was excellent in fluidity, and was also excellent in initial strength development and strength development after the initial stage, and these properties could be compatible with each other. On the other hand, in the polymer cement mortar in which the ratio of gypsum and quicklime and the particle size or content of the fine aggregate are not appropriate, both fluidity and strength development could not be achieved at the same time. In addition, the polymer cement mortar using early-strength cement was not hardened at the age of 2 hours.

Claims (6)

Fine bone containing fast-hardening cement, gypsum, fresh lime, a polymer for cement, fine aggregate A having a particle size of 0.6 mm or more, and fine aggregate B having a particle size of 0.09 mm or more and less than 0.3 mm. A fast-curing polymer cement composition comprising wood.
The mass ratio of the gypsum and the quicklime ([mass of gypsum] / [mass of quicklime]) is 1.1 or more.
The total content of the fine aggregate A and the fine aggregate B is 75 parts by mass or more with the total mass of the fine aggregate as 100 parts by mass.
A composition having a mass ratio of the fine aggregate A and the fine aggregate B ([mass of fine aggregate A] / [mass of fine aggregate B]) of 1.8 to 2.5 . The first aspect of the present invention, wherein the total content of the gypsum and quicklime is 2.5 to 20 parts by mass, with the total mass of the fast-curing cement, the gypsum and quicklime as 100 parts by mass. Composition. The composition according to claim 1 or 2, wherein the mass ratio of the gypsum and quicklime is 1.8 to 4. Taking the total mass of the fast-hardening cement, the gypsum, and the quicklime as 100 parts by mass,
The composition according to any one of claims 1 to 3, which comprises 10 to 50 parts by mass of the cement polymer and 200 to 350 parts by mass of the fine aggregate. The composition according to any one of claims 1 to 4, further comprising a water reducing agent. The composition according to any one of claims 1 to 5 and water are included.
A fast-curing polymer cement mortar containing 20 to 45 parts by mass of water, with the total mass of the fast-curing cement, the gypsum and quicklime being 100 parts by mass.