JP2926377B2 - Casting method of cement mortar composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for applying a cement mortar composition, and more particularly to a cement mortar having self-smoothness (self-leveling, hereinafter also referred to as SL) suitable for constructing a floor of a building. The present invention relates to a method for casting a composition.

[0002]

2. Description of the Related Art Conventionally, when building a floor of a building, a method has been adopted in which a cement mortar is cast on a concrete slab as an underlayer and the surface is flattened and smoothed with a metal iron. However, this method requires skilled plastering skills and requires much time and effort. In recent years, there has been a problem that it has become difficult to secure skilled plasterer technicians.

[0003] As a countermeasure against this problem, a powder obtained by mixing cement, gypsum, or the like as a base material and mixing it with an aggregate and various additives such as a fluidizing agent, a thickener, a defoaming agent, a setting regulator, and a dimensional stabilizer is used. Water is added to the body composition, and a composition having self-smoothness obtained by kneading (hereinafter, also referred to as SL material) is usually cast in a thickness of 10 mm on a floor base such as a concrete slab,
Curing methods have become widespread.

Recently, SL materials in a slurry state (hereinafter, also referred to as ready-mixed SL materials) have been manufactured in ready-mixed concrete factories, and ready-mixed SL materials prepared in ready-mixed concrete plants have been conventionally used similarly to ready-mixed concrete. Concrete
A method has been adopted in which a mixer truck is used to carry the material to a construction site, cast it onto a concrete slab at the construction site, and cure it.

[0005]

However, some of the additives for SL used in the production of the raw SL material have an adverse effect on the quality of the ready-mixed concrete for ordinary use. In the conventional method, the raw SL material obtained by kneading is difficult to remove and remains in the manufacturing facility, so that the ready-mixed concrete manufacturing facility cannot be shared and a dedicated raw SL material manufacturing facility is required. And Therefore, the raw SL material can be supplied only from a specific factory where the raw SL material manufacturing equipment is provided.

In addition, since the raw SL material decreases in fluidity over time after being prepared, the time required for the raw SL material to flow is limited. In the case where a long time elapses from the preparation to the pouring, deterioration in quality is inevitable. For this reason, according to the conventional method, a flowable construction site capable of receiving and using raw SL material of stable quality is located in an area close to a specific factory where the raw SL material manufacturing equipment is provided. There is a problem that it is limited.

[0007] The inventors of the present invention can share ordinary raw material production equipment and supply raw SL material by specifying the mixing and kneading conditions of various raw materials for raw green material production in a ready-mixed plant mixer. A method has been proposed in which the area can be expanded, a smooth and good cured body free from efflorescence, protrusions and air bubble marks is formed, and a finished floor surface with good level accuracy can be easily obtained.

The present inventors have further attempted to shorten the kneading time of various materials for producing raw SL material in a ready-mixed plant mixer to meet the conditions for producing a base cement mortar for ready-mixed concrete for ordinary use. . However, in ready-mixed concrete base cement mortar for general use,
Since the water cement ratio is usually smaller than 0.5 and the mixing ratio of water to solids is small, the dispersion of each material is good even in a short-time kneading process. In order to increase the fluidity of the raw SL material, the mixing ratio of water to cement is set higher than that of the ordinary base cement mortar for ready-mixed concrete to make the water cement ratio 0.5 or more. The mass of the material (mamako) does not easily collapse and flows while maintaining the mass, resulting in poor dispersion, making it difficult to enhance the kneading effect of the material.

From the above, fine aggregate having a particle size of 5 mm or less, which is used for ordinary civil engineering and construction, is blended.
Mix a base cement mortar prepared by adding water so that the water-cement ratio becomes 0.5 or more with a fluidizing agent, thickener, defoamer, and other additives to impart self-smoothness. When the slurry is kneaded using a slurry, if the kneading conditions are not appropriate, the dispersion of the fine aggregate in the slurry is poor, and the aggregate of the fine aggregate formed by compacting in the material hopper is obtained. When the ready-mixed SL material was manufactured using the ready-mixed concrete manufacturing equipment, coarse aggregate (particle size: 5 to 20 mm) for the ready-mixed concrete remaining in the manufacturing apparatus was manufactured. Mixed with raw SL material, S
Fluidity, which is an important performance of the L material, varies, and a composition having the intended self-smoothness cannot be obtained. When such a raw SL material is poured on a floor substrate, the cured There is a problem that a smooth surface is not formed and a stable quality floor is not formed.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems and to share a common ready-mixed concrete production facility, thereby greatly reducing the work of handling powder and heavy materials at a construction site. Area can be expanded without limitation, the aggregate of fine aggregate and coarse aggregate contained in the raw SL material can be removed, and a uniform SL material can be obtained. Casting of a cement mortar composition with self-smoothness that can produce a smooth and good cured body with no air bubble traces and has a good level accuracy, and can save labor and stabilize floor quality. It is to provide a method.

[0011]

Means for Solving the Problems The present inventors have conducted intensive studies, and made a raw SL material obtained by kneading with a raw conplant mixer to flow through a sieve having an opening of 5 to 15 mm. As a result, a smooth and good cured body without white spots, protrusions and air bubble traces is formed, and a finished floor surface with high level accuracy can be easily obtained. The present inventor has found that the area where the SL material can be supplied can be expanded, and the work of handling heavy objects at the construction site is greatly reduced.

The present invention relates to a method for producing a cement mortar composition comprising a cement, a fine aggregate, and water, which is obtained by kneading with a raw plant mixer. A method of casting a cement mortar composition, which comprises passing through a sieve having a range of 5 to 15 mm in advance.

[0013] The method of the present invention is further characterized in that the cement mortar composition comprises cement, fine aggregate and water, and is prepared by adding water so that the water-cement ratio is 0.5 or more. When the composition contains an additive for imparting smoothness, the composition can be suitably applied.

Hereinafter, the present invention will be described in detail. A cement mortar composition to which the method of the present invention can be suitably applied is a cement mortar composition also referred to as a cement, a fine aggregate, a base cement mortar containing water (hereinafter, also simply referred to as a base mortar), A base mortar prepared by adding water so that the water-cement ratio becomes 0.5 or more, and a cement mortar composition having self-smoothness obtained by blending an additive for enhancing the self-smoothness with the base mortar (Hereinafter, also referred to as SL composition). The SL composition is composed of a base mortar and various additives such as a fluidizer, a thickener, and an antifoaming agent. As additives other than the above, a curing accelerator, a curing retarder, a shrinkage reducing agent, a swelling agent, and the like can be used as necessary.

[0015] The base mortar constituting the SL composition is usually a mixture of cement, fine aggregate and water. As cement, ordinary Portland cement, early strength Portland cement, moderate heat Portland cement, blast furnace cement, silica cement, fly ash cement,
Various cements such as alumina cement and jet cement can be used. The amount of cement used per 1 m ^{3 of} base mortar (amount of cement) is usually preferably in the range of 300 to 900 kg / m ³ .

As the fine aggregate, those used in general ready-mixed concrete production can be used. The fine aggregate has a particle size of 5 mm or less and a coarse particle ratio of 2 to 3. preferable. The weight ratio (S / C, fine aggregate cement ratio) between the fine aggregate weight S and the unit cement amount C is usually preferably in the range of 0.5 to 4.

Weight ratio of unit water amount W to unit cement amount C
(W / C, water cement ratio) is usually 0.5 or more, preferably
It is better to be in the range of 0.6 to 1.4.

Examples of the fluidizing agent include melamine formalin condensate sulfonate, lignin sulfonate, polyalkylallyl sulfonate, β-naphthalene sulfonate condensate, polycarboxylate and the like. Alternatively, two or more kinds can be used in combination. The addition amount of the fluidizing agent is somewhat different by the type, 1 m ³ per base mortar, usually, it is in the range of 2 to 10 kg.

Examples of the thickener include cellulose ethers such as methylcellulose, ethylcellulose, hydroxyethylcellulose and carboxymethylcellulose, and various water-soluble polymers such as polyacrylamide, polyethylene oxide, polyvinyl alcohol and casein. Two or more can be used in combination. The addition amount of the thickener varies somewhat depending on the type and molecular weight, 1 m ³ per base mortar, usually, it is in the range of 0.5 to 5 kg.

Examples of the antifoaming agent include various antifoaming agents such as alcohol-based, polyol-based, fatty acid ester-based, ethylene oxide-propylene oxide-based, and silicon-based antifoaming agents. These may be used alone or in combination of two or more. be able to. The addition amount of the antifoaming agent are somewhat different depending on the kind, 1 m ³ per base mortar, usually, 0.3～1Kg
It is good to be in the range of.

The SL composition which is the object of the method of the present invention comprises a base mortar containing cement, fine aggregate and water, a fluidizing agent, a thickening agent, It can be obtained by appropriately combining various additives such as a foaming agent, and kneading. A device for kneading the SL composition is not particularly limited, but a device having good kneading performance called a forced kneading mixer is usually used. The forced kneading mixer is widely used as a ready-mix plant mixer in a general ready-mix plant. The kneading time is in the range of 0.5 to 2 minutes, similarly to the conditions for producing a base cement mortar for ready-mixed concrete for ordinary use.

In the method of the present invention, the cement mortar composition obtained by kneading with a raw conplant mixer—the base mortar or the SL composition is passed through a sieve.
It is possible to break down and disperse a lump mainly composed of lump of fine aggregate contained in the cement mortar composition, and it is possible to remove mixed coarse aggregate and to homogenize the cement mortar composition. Can be done.

The sieve used for treating the cement mortar composition in the method of the present invention has an opening of 5 to 15 meshes.
It should be in the range of mm. When the mesh size of the sieve is less than 5 mm, fine aggregate dispersed and contained in the cement mortar composition does not pass through the sieve, which hinders the treatment of the cement mortar composition and lowers working efficiency. On the other hand, if the opening of the sieve exceeds 15 mm, the effect of dispersing the lump is small, and the mixed coarse aggregate cannot be removed by passing through the sieve. When the obtained cement mortar composition is cast, a smooth cured body surface is not formed.

It is to be noted that a plurality of sieves having different openings can be used in combination from the one having the larger opening to the one having the smaller opening. Further, when processing a cement mortar composition containing a large amount of aggregates and aggregates having a size of more than 15 mm, roughing is performed by combining a sieve having an opening of an appropriate size exceeding 15 mm as a preliminary treatment. Operations can be performed.

The capacity of the sieve is preferably such that the cement mortar composition can be processed at about 20 to 100 liters per minute. Further, it is preferable that it is structurally able to withstand vibration even when a vibrator is attached.

An example of an embodiment of the method of the invention is given below.
The method of the present invention is not limited to this. The cement mortar composition targeted by the method of the present invention is a raw SL
Not only those manufactured with manufacturing equipment dedicated to materials but also those manufactured in common with ready-mixed concrete manufacturing equipment may be used, and the manufactured cement mortar composition generally transports ready-mixed concrete to the site of civil engineering and construction work It can be transported by the mixer truck used at the time.

The sieving treatment of the cement mortar composition, which is a feature of the method of the present invention, is performed when the cement mortar composition produced by the raw conplant mixer is transferred into the mixer truck or when the cement mortar composition is transported by the mixer truck. It can be applied when transferring the mortar composition to a hopper such as a mortar pump provided at the construction site. After the sieving treatment is performed, an embodiment in which the sieving treatment is performed and the mixture is poured to a construction site using a mortar pump or the like, and is leveled and hardened using a surface leveling tool such as a register mark is possible.

[0028]

The method of the present invention has the following effects. 1) It is possible to obtain a homogeneous SL composition with a good dispersion of fine aggregate and various additives, and a smooth and good cured product without white spots, protrusions and air bubble marks is formed, and the level accuracy is good. The floor can be easily obtained. 2) The SL composition can be manufactured using the common ready-mixed concrete production equipment, thereby increasing the degree of freedom in the area where the SL composition can be used, and supplying the SL composition. Possible areas can be expanded. 3) Since the work of handling powder and heavy objects at the construction site is greatly reduced, the work efficiency is improved, and the contamination of the work environment by dust can be prevented. 4) Compared with the conventional construction method, it is possible to greatly reduce labor when constructing a building floor and stabilize the quality of the finished floor surface.

[0029]

The present invention will be described in detail below with reference to examples and comparative examples. As long as the present invention does not exceed the gist,
It is not limited to the following embodiments. Examples 1 and 2 and Comparative Examples 1 and 2. Cement, fine aggregate and water were kneaded at a mixing ratio described later using a raw conplant mixer to prepare a base mortar slurry of 0.5 m ³ each. The obtained base mortar slurry was transferred to a mixer truck while being sieved under the conditions shown in Table 1. This additive was added at below the mixing ratio, total flow of the SL composition obtained by kneading in a mixer cars, each with a mortar pump 20mm thickness on the concrete slab 25 m ^2, Dragonfly And natural hardening. During the sieving treatment, vibration was applied to the sieve with a vibrator.

Examples 3 to 6 and Comparative Examples 3 to 5. Using a raw conplant mixer, the materials were kneaded at the mixing ratio described below to obtain a 5 m ³ slurry SL composition.
This was transferred to a mixer truck. After treating each 0.5 m ³ of the SL composition slurry transferred to the mixer truck under the conditions shown in Table 1, each was poured into a concrete slab 25 m ^{2 at} a thickness of 20 mm using a mortar pump, and evenly distributed with a register mark. And naturally cured. During the sieving treatment, vibration was applied to the sieve with a vibrator.

The main materials and the compounding ratios used in the test are as follows. <Material> ・ Cement… Normal Portland cement ・ Fine aggregate ・ ・ ・ Table specific gravity: 2.6, coarse particle ratio: 2.7 ・ Additive (a): Superplasticizer “SMF-PD” (manufactured by Nissan Chemical Industries, Ltd.) (b) : Thickener "hi-metroz 90SH 30000" (Shin-Etsu Chemical Co., Ltd.) (c): Defoamer "SN Deformer 14 HP" (San Nopco) <Material composition ratio>: Unit amount, (kg / m ³ Cement (C): 550, Fine aggregate (S): 1100, Aggregate ratio (S / C): 2.0 Water (W): 410, Water ratio (W / C): 0.75 Additive (a): 4 , (b): 1, (c): 0.5

Table 1 shows the conditions and properties of the base mortar slurry or the SL composition slurry passed through the sieve in each test and the surface condition of the formed cured product.

[0033]

[Table 1]

The method of measuring or testing each evaluation item shown in Table 1 is as follows.・ Situation of passing through sieve ... Base mortar slurry or SL
It was determined whether the aqueous composition slurry smoothly passed through the sieve. -Properties of the SL composition slurry: SL that has been cast
The presence or absence of a lump in the aqueous composition slurry was visually determined.・ Surface condition of cured body (white flower / projection and bubble mark)… S
The L-type composition was cast at a thickness of 20 mm, and after 7 days at 20 ° C. and 60% RH, the composition was visually observed and touched to determine the evaluation.・ Whether the next day's light walking is possible ... Run the SL composition at a thickness of 20mm, and after riding for 12 hours at 20 ℃, RH60%, get on the shoes with rubber soles and see if there are any traces of the soles on the surface of the cured body. Was visually observed and judged. -Level accuracy of cured product: The level accuracy of the surface of the formed cured product was measured using a level.

The meanings of the symbols in the columns of each evaluation item shown in Table 1 are as follows.・ Situation of passing through sieve: ○… Smoothly passing. ×…
-Does not pass smoothly.-Property of cement mortar composition slurry: ○: Good dispersion of material. ×: Lumps exist.
Yes. ・ Possibility of light walking the next day: ○… Yes. ×…
No. ・ Level accuracy: ○… 1/300 or less, ×…
Over 1/300;

In each of Examples 1 to 6 tested under the conditions satisfying the requirements of the present invention, a smooth and good cured product was formed, and a floor surface with high level accuracy was obtained.

On the other hand, in Comparative Examples 1 and 2, the sieves used in the base mortar slurry were used. In Comparative Examples 3 and 4, the sieves used in the SL composition slurry were used. The results were out of the range specified in the present invention, and no satisfactory results were obtained. In Comparative Examples 1 and 3, the mesh size of the used sieve was smaller than the range specified in the present invention, and a part of the blended fine aggregate was removed by the sieve treatment. It was bad. On the other hand, in Comparative Example 2 or 4, since the mesh of the used sieve was larger than the range specified in the present invention, dispersion or removal of the lump present in the cement mortar composition slurry was insufficient and formed. The properties of the cured product were poor. Comparative Example 5 is based on the base mortar slurry and SL
In this case, no sieving treatment was applied to any of the slurry of the composition, and there were lumps in the cast SL composition slurry, and the properties of the formed cured product were poor.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) E04F 15/12 E04G 21/00-21/10

Claims (3)

(57) [Claims] 1. A cement mortar composition containing cement, fine aggregate and water, obtained by kneading with a raw conplant mixer, is poured and the cement mortar composition has an opening of 5 to 15 mm. A method for casting a cement mortar composition, characterized in that the composition is passed through a sieve in the range of (1) to (4) in advance. 2. The casting method according to claim 1, wherein the cement mortar composition is prepared by adding water so that the water-cement ratio becomes 0.5 or more. 3. The casting method according to claim 1, wherein the cement mortar composition contains cement, fine aggregate, and water, and further contains an additive for imparting self-smoothness.