JP2019064884A - Polymer cement mortar composition and polymer cement mortar - Google Patents

Abstract

To provide a polymer cement mortar composition that has excellent trowelling properties and is difficult to drop.SOLUTION: A polymer cement mortar composition comprises (A) a hydraulic cement, (B) a fine aggregate, (C) a light-weight aggregate, (D) a polymer for cement, and (F) fibers, such as a cellulose fiber, having a fiber length of 10 mm or less, wherein: the content of the (B) component is 110-270 pts.mass based on 100 pts.mass of the (A) component; and the content of the (F) component is 0.2-10 pts.mass based on 100 pts.mass of the (A) component.SELECTED DRAWING: None

Description

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

  Cracks occur in concrete structures (for example, reinforced concrete (RC) floor slabs or floor slabs such as the inner floor slabs of box culverts, walls, and ceilings) due to factors such as fatigue and drying shrinkage. As this type of deterioration progresses or cracks are rubbed together, when the crack width becomes large, deterioration factors such as water and chloride ions intrude into the concrete structure from the deteriorated portion. As a result, the rebar embedded in the concrete structure is corroded. If the damage due to the cracking of the concrete structure is left, the inner rebars eventually corrode and the cross section is lost, and the safety of the structure can not be maintained. For this reason, after removing the deteriorated part, filling the repair material or the reinforcing material in the recess is performed.

  As a repair material or a reinforcing material, a polymer cement mortar has been proposed (for example, Patent Document 1 and Patent Document 2).

JP, 2015-000820, A JP 2005-015306 A

  The polymer cement mortar used as a repair material or a reinforcing material is required to have workability (iron properties) by a iron treatment because it is finished with a iron after being filled in a recess. Moreover, a polymer cement mortar may see a dripping with the contained polymer, and the further improvement of this dripping is also calculated | required. However, it has been difficult to simultaneously achieve good iron properties and suppression of dripping.

  Accordingly, an object of the present invention is to provide a polymer cement mortar composition and a polymer cement mortar which have good iron properties and are less likely to drip.

  As a result of intensive studies on the above problems, the present inventors have found that using fine aggregate and lightweight aggregate in combination and adjusting the amount of fine aggregate and fibers having a specific fiber length is good. It has been found that a polymer cement mortar composition and a polymer cement mortar which have iron properties and are resistant to dripping can be obtained.

That is, the present invention is shown by the following [1] to [5].
[1] (A) hydraulic cement, (B) fine aggregate, (C) lightweight aggregate, (D) polymer for cement, and (F) fibers having a fiber length of 10 mm or less and containing (B) component The amount is 110 to 270 parts by mass with respect to 100 parts by mass of the component (A), and the content of the component (F) is 0.2 to 10 parts by mass with respect to 100 parts by mass of the component (A). , Polymer cement mortar composition.
[2] The polymer cement mortar composition of [1] whose content of (C) component is 1-25 mass parts with respect to 100 mass parts of (A) components.
[3] The polymer cement mortar composition of [1] or [2] whose content of (D) component is 2-45 mass parts in conversion of solid content with respect to 100 mass parts of (A) component.
[4] The polymer cement mortar composition according to any one of [1] to [3], wherein (C) component / ((B) component + (C) component) is 0.02 to 0.10 on a mass basis.
[5] The polymer cement mortar composition according to any one of [1] to [4] and water, the content of water being 20 to 45 parts by mass with respect to 100 parts by mass of the component (A), Polymer cement mortar.

  According to the present invention, it is possible to provide a polymer cement mortar composition and a polymer cement mortar which have good iron properties and are resistant to dripping.

  Hereinafter, although an embodiment of the present invention is described in detail, the present invention is not limited to this.

  The polymer cement mortar composition of the present embodiment comprises (A) hydraulic cement, (B) fine aggregate, (C) lightweight aggregate, (D) polymer for cement and (F) fibers having a fiber length of 10 mm or less. Including.

(A) A variety of hydraulic cements can be used, and examples thereof include various Portland cements such as normal, early strength, ultra early strength, low heat and moderate heat, eco cement, quick setting cement and the like. A hydraulic cement may be used individually by 1 type, and may be used in combination of 2 or more types.
Quick-setting cement is preferably those containing calcium aluminates as an active _{ingredient, 11CaO · 7Al 2 O 3 ·} CaX 2 (X represents a halogen atom) or _{3CaO · 3Al 2 O 3 · CaSO} 4 a (Auin) It is more preferable to contain it as an active ingredient. 11CaO · 7Al ₂ O ₃ · CaX ₂ is a so-called calcium aluminate halide cement. The halogen atom is preferably a fluorine atom. In addition, auin is also called calcium sulfoaluminate cement (auin cement). These are called ultra rapid-hardening cements and are marketed under the trade name jet cement or super jet cement. The fast setting cement is most preferably an auin cement.
In addition, as calcium aluminates, when CaO is indicated by C, Al ₂ O ₃ by A, Fe ₂ O ₃ by F, C ₃ A, C ₂ A, C ₁₂ A ₇ , C ₅ Calcium aluminate with a mineral composition denoted as A ₃ , CA, C ₃ A ₅ , CA ₂ etc., calcium aluminoferrite denoted as C ₂ AF, C ₄ AF etc etc, alumina cement, and also SiO ₂ , _{K 2 O, Fe 2 O 3} , TiO 2 or the like include such as those in solid solution or compound. The calcium aluminates may be either crystalline or amorphous, or may be a mixture of crystalline and amorphous. A quick-hardening admixture prepared by blending these calcium aluminates and an inorganic salt such as gypsum and added to portland cement can also be used as a quick-hardening cement.

  The fine aggregate (B) is not particularly limited, and examples thereof include river sand, silica sand, crushed sand, cold water stone, limestone sand, slag aggregate and the like. Among them, it is preferable to use fine aggregate such as silica sand or limestone adjusted to a particle size free of fine powder and coarse aggregate. As the fine aggregate, it is preferable to use one having a particle diameter of 5 mm or less which is usually used (5 mm sieve passing part). The fine aggregate may be used alone or in combination of two or more.

  The content of the fine aggregate (B) is 110 to 270 parts by mass with respect to 100 parts by mass of the hydraulic cement (A). (B) When the content of the fine aggregate is outside the above range, when it is made into mortar, the fluidity and the iron property become poor, and it is difficult to obtain sufficient compressive strength at the time of hardening. From the viewpoint of better fluidity and iron properties of mortar and improvement in compressive strength at curing, the content of (B) fine aggregate is 120 to 200 parts by mass with respect to 100 parts by mass of (A) hydraulic cement And preferably 120 to 170 parts by mass.

  (C) The lightweight aggregate is not particularly limited. For example, pearlite which is an inorganic foamable aggregate obtained by firing and forming obsidian, fly ash balloon generated in a thermal power plant, foam glass particles (glass balloon Etc.). It is preferable to use a lightweight aggregate having a particle diameter of 5 mm or less which is usually used (5 mm sieve passing portion). The lightweight aggregate may be used singly or in combination of two or more. The lightweight aggregate preferably has, for example, a bulk specific gravity (kg / L) of 0.1 to 0.8 and more preferably 0.15 to 0.6. If the bulk specific gravity of the lightweight aggregate is within the above range, the effect of weight reduction is easily obtained, and the fluidity when used as a mortar tends to be unlikely to decrease.

  The content of the lightweight aggregate (C) is preferably 1 to 25 parts by mass, more preferably 1 to 15 parts by mass, and more preferably 2 to 10 parts by mass with respect to 100 parts by mass of (A) hydraulic cement. Even more preferably it is part. (C) When the content of the lightweight aggregate is in the above range, a good iron-like property is easily obtained when it is used as mortar, it is difficult to drip, and the compressive strength at the time of hardening is easily improved.

  It is preferable that the polymer cement mortar composition of this embodiment is mix | blended by a fixed mass ratio with the (B) fine aggregate and the (C) lightweight aggregate. Specifically, (C) lightweight aggregate / ((B) fine aggregate + (C) lightweight aggregate) is preferably 0.02 to 0.10 on a mass basis, and 0.02 to 0 More preferably, it is .097, and still more preferably 0.02 to 0.06. If the mass ratio of the fine aggregate to the lightweight aggregate is within the above range, good mortar properties are easily obtained when it is used as a mortar, dripping is less likely to occur, and compressive strength at the time of curing is more easily improved.

(D) The polymer for cement is preferably a polymer defined in JIS A 6203: 2015 “Polymer dispersion for cement mixing and redispersible powder resin”. Examples of such cement polymers include polymer dispersions, re-emulsifiable powder resins and the like. Examples of the polymer dispersion include synthetic rubbers such as styrene butadiene rubber (SBR); natural rubbers; rubber asphalts; ethylene vinyl acetates; acrylic esters; and resin asphalts. Among the polymer dispersions, synthetic rubbers, ethylene vinyl acetates and acrylic esters are preferable, and specifically, synthetic rubber latex, polyacrylic esters and ethylene vinyl acetate are more preferable. Examples of re-emulsifiable powder resins include synthetic rubbers such as styrene butadiene rubber; acrylic esters; ethylene vinyl acetates; vinyl acetate / versatric acid vinyl esters; vinyl acetate / versaic acid esters / acrylic acid esters. As the cement polymer, a polymer dispersion may be used, a re-emulsifiable powder resin may be used, and a polymer dispersion and a re-emulsifiable powder resin may be used in combination.
Among cement polymers, polymer dispersion of styrene butadiene rubber and / or re-emulsified powder resin is preferable from the viewpoint of further improving the adhesion to concrete. Styrene butadiene rubber is a kind of synthetic rubber obtained by copolymerizing styrene and butadiene, and the quality can be appropriately adjusted by the styrene content and the amount of vulcanization. For cement mixing, the amount of bound styrene is often 50 to 70% by mass, and stability and adhesiveness are improved and used. The cement polymer may be used alone or in combination of two or more.

  The content of the (D) polymer for cement is preferably 2 to 45 parts by mass in terms of solid content, and more preferably 5 to 40 parts by mass with respect to 100 parts by mass of (A) hydraulic cement. It is further more preferable that it is 10-30 mass parts, and it is most preferable that it is 10-25 mass parts. (D) When the content of the polymer for cement is in the above range, when it is used as mortar, it is easy to obtain good fluidity and iron properties, and it is difficult to drip.

  The type of fibers (F) is not particularly limited as long as the fiber length is 10 mm or less, and natural fibers or chemical fibers may be used. Examples of natural fibers include plant fibers and animal fibers. Examples of chemical fibers include inorganic fibers such as glass, natural polymer fibers such as rayon and cellulose, polyvinyl alcohol fibers such as vinylon, polyamide fibers such as nylon, and various other synthetic fibers. The fibers are preferably those having durability against the alkali component of cement. The fibers may be used alone or in combination of two or more.

  (F) The fiber length of fibers is 10 mm or less. (F) If the fibers having a fiber length of 10 mm or less are not blended, the fluidity and the iron property become poor when it is made into mortar, sagging easily occurs, and it is difficult to obtain sufficient compressive strength at the time of curing. The fiber length of the (F) fibers is preferably 0.1 to 10 mm, preferably 0.1 to 5 mm, from the viewpoint of better fluidity, iron and dare properties of the mortar, and improvement in compressive strength during hardening. Is more preferably 0.1 to 1 mm, and most preferably 0.1 to 0.8 mm.

  The content of (F) fibers is 0.2 to 10 parts by mass with respect to 100 parts by mass of (A) hydraulic cement. When the content of the fibers (F) is outside the above range, when it is made into mortar, the fluidity and the iron property become poor, and sagging tends to occur. The content of (F) fibers is 0.2 to 5 parts by mass with respect to 100 parts by mass of (A) hydraulic cement from the viewpoint of better fluidity, iron properties and drip properties of mortar Preferably, 0.2 to 3 parts by mass is more preferable, and 0.2 to 1.5 parts by mass is even more preferable.

  The polymer cement mortar composition of the present embodiment may partially contain fibers having a fiber length of more than 10 mm as long as the effects of the present invention are not impaired.

  The polymer cement mortar composition of the present embodiment may contain a water reducing agent. The water reducing agent includes a high performance water reducing agent, a high performance AE water reducing agent, an AE water reducing agent, and a fluidizing agent. As such a water reducing agent, the water reducing agent prescribed | regulated to JIS A 6204: 2011 "chemical admixture for concrete" is mentioned. Examples of water reducing agents include polycarboxylic acid-based water reducing agents, naphthalene sulfonic acid-based water reducing agents, lignin sulfonic acid-based water reducing agents, melamine-based water reducing agents, and acrylic water-reducing agents. Among these, naphthalenesulfonic acid-based water reducing agents are preferred. A water reducing agent may be used individually by 1 type, and may be used in combination of 2 or more types.

  It is preferable that it is 0.5-7.5 mass parts with respect to 100 mass parts of (A) hydraulic cement, and, as for content of a water reducing agent, it is more preferable that it is 1-4 mass parts. When the content of the water reducing agent is within the above range, when the mortar is used, better flowability and iron-like properties are easily obtained, sagging is difficult, and compressive strength at the time of curing is also easily improved.

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

  The content of the setting retarder is preferably 0.3 to 7.5 parts by mass, and more preferably 0.5 to 5 parts by mass with respect to 100 parts by mass of (A) hydraulic cement. If the content of the setting retarder is within the above range, it is easier to secure the pot life and the initial strength development tends to be difficult to reduce.

  Various admixtures may be added to the polymer cement mortar composition of the present embodiment as long as the effects of the present invention are not impaired. Examples of the admixture include antifoaming agents, waterproofing agents, rustproofing agents, shrinkage reducing agents, thickeners, water retention agents, pigments, water repellents and anti-whitening agents.

  The polymer cement mortar composition of the present embodiment can be prepared by mixing the above-described components with a commonly used kneading device, and the device is not particularly limited. Examples of the kneading apparatus include a Hobart mixer, a hand mixer, a tilting cylinder mixer, and a biaxial mixer.

  The polymer cement mortar composition of the present embodiment can be mixed with water to prepare a mortar, and the water content may be appropriately adjusted according to the application. The content of water is preferably 20 to 45 parts by mass, more preferably 22 to 38 parts by mass, and 24 to 34 parts by mass with respect to 100 parts by mass of (A) hydraulic cement. Even more preferred. If 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 initial strength development.

  Preparation of the polymer cement mortar of this embodiment can use the same kneading apparatus as a normal polymer cement mortar, and is not particularly limited. As the kneading device, for example, those described above can be used.

  The polymer cement mortar composition and the polymer cement mortar of the present embodiment have good iron-like properties and are resistant to dripping, so they have excellent workability and a clean finish. Therefore, such a polymer cement mortar composition and a polymer cement mortar prepared using the same can also be used, for example, as a repair / reinforcing material for concrete structures, steel-concrete composite structures, roads, and the like. The method of using the polymer cement mortar composition and the polymer cement mortar of the present embodiment can be selected appropriately, for example, a method of filling the recess with a iron, a method of filling with a vibrator after filling and finishing with a iron, etc. The method of spraying etc. can be selected.

  Hereinafter, the present invention will be described in detail by way of examples, but the present invention is not limited thereto. The materials used are shown in Table 1.

[Composition design of polymer cement mortar composition]
Fine aggregate, lightweight aggregate, polymer for cement (solid content conversion) and fiber materials were compounded and designed to be as shown in Table 2 with respect to 100 parts by mass of hydraulic cement. The water reducing agent was 2 parts by mass and the setting retarder was 2 parts by mass with respect to 100 parts by mass of the hydraulic cement. No. The 22 formulation does not contain a set retarder.

[Preparation of polymer cement mortar]
Add cement polymer (polymer dispersion) to a 10 L cylindrical container under an environment of 20 ° C, add each material of the polymer cement mortar composition formulated according to Table 2 and water, and knead with a hand mixer for 90 seconds Then, about 3 L of polymer cement mortar was produced.

[Evaluation method]
Each item was evaluated by the following method. The evaluation results are shown in Table 3.
・ Consistency JIS R 5201: 2015 “Physical test method of cement” 12. According to the flow test, the flow value of the polymer cement mortar was measured in a 20 ° C. environment, and this was evaluated as the consistency.
-Properties of the polymer cement mortar was applied to a formwork (30 x 30 x 3 cm) and then leveled with a cloth to evaluate the properties of the polymer cement mortar. When the time from mortar construction to finishing of finishing is required for 5 minutes or more, the iron property is evaluated as poor (x), and the iron property is good when 5 minutes for finishing work is not required. Among those evaluated as (() and the iron quality was evaluated as good, when the polymer cement mortar did not adhere to the iron, the iron quality was evaluated as particularly good (◎).
Dare Properties A formwork (30 × 30 × 3 cm) was placed in a state of a gradient of 5%, and a polymer cement mortar was applied and then leveled with a cloth to visually observe the drip property of the polymer cement mortar. Those in which the sag occurred were evaluated as defective (x), and those in which the sag did not occur were evaluated as good (o).
・ Compressive strength According to JSCE-G 505-2010 “Test method for compressive strength of mortar or cement paste using cylindrical specimen (draft)”, the compressive strength of hardened polymer cement mortar at a material age of 28 days It was measured. The dimensions of the specimen were 50 mm in diameter and 100 mm in height. The specimen was demolded on the next day of preparation and then cured in air until the material age. Curing was always performed in a thermostat at 20 ° C.

Claims (5)

(A) hydraulic cement, (B) fine aggregate, (C) lightweight aggregate, (D) polymer for cement and (F) fibers having a fiber length of 10 mm or less,
The content of the component (B) is 110 to 270 parts by mass with respect to 100 parts by mass of the component (A), and the content of the component (F) is 100 parts by mass of the component (A). , 0.2 to 10 parts by mass, a polymer cement mortar composition.   The polymer cement mortar composition of Claim 1 whose content of the said (C) component is 1-25 mass parts with respect to 100 mass parts of said (A) components.   The polymer cement mortar composition of Claim 1 or 2 whose content of the said (D) component is 2-45 mass parts in conversion of solid content with respect to 100 mass parts of said (A) components.   The polymer cement mortar composition according to any one of claims 1 to 3, wherein the component (C) / (the component (B) + the component (C)) is 0.02 to 0.10 on a mass basis. object. A polymer cement mortar composition according to any one of claims 1 to 4 and water.
The polymer cement mortar whose content of the said water is 20-45 mass parts with respect to 100 mass parts of said (A) components.