JPH06136922A - Constructing method of self-smoothing cement mortar composite - Google Patents

Abstract

PURPOSE:To form a floor surface having self-smoothing property by kneading a composite obtained by combining a fluidizing agent, a thickener, and a defoaming agent together in proper addition quantities to a base cement mortar having a blend ratio within a determined range under a regulated condition. CONSTITUTION:To a base cement mortar in which cement quantity per m<3> is within the ratio of 300-550kg, water/cement ratio within the range of 0.6-1.4, and sand/cement ratio within the range of 0.5-4, 2-10kg, per m<3>, of a fluidizing agent, 0.5-5kg of a thickener, and 0.3-1kg of a defoaming agent are added, and the mixture is kneaded within the range of 0.5-2 minutes by use of a forced kneading mixer, and casted in a flow value within the range of 20-35cm followed by hardening. The defoaming agent is used in combination of one or two kinds or more, as occasion demands, to arrest the deterioration of the formed hardened body surface and reduction in strength of the hardened body caused by hardening while bubbles are still generated on the surface. As occasion demands, a hardening accelerator/retardant, a compression reducing agent, and an expanding agent may be used as additives.

Description

Detailed Description of the Invention

[0001]

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

[0002]

2. Description of the Related Art Conventionally, when constructing a floor of a building, a method of placing cement mortar on a concrete slab as a base and finishing the surface flat and smooth with a metal iron is used. However, this method requires a lot of time and labor as well as skilled plasterer skills. In recent years, it has become difficult to secure skilled plasterers. Therefore, as a countermeasure against this, a powder composition in which cement or gypsum is used as a base material, and various additives such as an aggregate and a fluidizing agent, a thickener, a defoaming agent, a curing regulator, and a dimensional stabilizer are mixed with the base material. A method in which a composition having self-smoothness obtained by kneading by adding water (hereinafter, also referred to as SL material) is cast in a thickness of 10 mm on a floor substrate and then cured to spread it has become popular. Recently, a slurry SL material (hereinafter,
Raw SL materials) are now manufactured in ready-mixed concrete factories, and raw SL materials prepared in ready-mixed concrete factories are used in the same manner as conventional concrete.
A method is used in which a mixer truck is used to bring the product to the construction site and cast it on the concrete slab at the construction site to cure it.

[0003]

However, the base cement mortar used for the production of general ready-mixed concrete, which is used for ordinary civil engineering and construction and which contains fine aggregate having a particle size of 5 mm or less, has self-smoothness. When adding a fluidizing agent for imparting, a thickener, a defoaming agent and other additives and adding water, when kneading into a slurry using a mixer,
If the compounding conditions are not appropriate, self-smoothness cannot be obtained, or the desired cured physical properties cannot be obtained. Further, if the kneading conditions are not appropriate, the dispersion of the fine aggregate in the obtained slurry is poor and a large lump is present so that a smooth surface cannot be obtained, or the kneading composition thickly adheres to the inside of the mixer to remove it. It becomes difficult. Furthermore, a large amount of air bubbles are mixed in the kneading composition to lower the fluidity, and a composition having the desired self-smoothness cannot be obtained, and the fluidity, which is an important performance as an SL material, varies and is stable. There is a problem that a floor base of the given quality is not formed.

Some of the above-mentioned SL-forming additives used in the production of raw SL materials have an adverse effect on the quality of 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 equipment, so the raw concrete manufacturing equipment cannot be shared and a dedicated raw SL material manufacturing equipment is required. And Therefore, the raw SL material can be supplied only from a specific factory where the raw SL material manufacturing facility is provided. Moreover, raw S
After the L material is prepared, its fluidity decreases with the passage of time, and therefore the time until casting is restricted. If it takes more than 1 hour to prepare and cast the product, deterioration of quality is unavoidable. Therefore, according to the conventional method, the raw slant construction site that can receive and use the raw SL material of stable quality is the raw SL material.
There is a problem that it is limited to the area close to a specific factory where the material manufacturing facility is provided.

The object of the present invention is to solve the above problems, to significantly reduce the work of handling powders and heavy objects at the construction site, and to expand the area where the SL material can be supplied without limitation. A self-smoothing cement that is smooth, has no hard spots, protrusions, and air bubbles, and has a good level of precision, and that provides a finished floor surface with good level accuracy, which can save labor and stabilize floor quality. It is to provide a construction method of a mortar composition.

[0006]

Means for Solving the Problems As a result of intensive studies, the inventors of the present invention have defined a range of a blending ratio of materials for a base cement mortar, and have a specific amount of flow for imparting self-smoothness to the range. By defining the time for kneading with a mixer by adding an agent, a thickener and a defoaming agent, and casting the obtained cement mortar composition at a flow value within a specific range, white flowers, protrusions and bubble traces A smooth and good hardened body is formed, and a finished floor surface with good level accuracy can be easily obtained, and the work of handling heavy objects at the construction site is greatly reduced, and common equipment for manufacturing ready-mixed concrete is shared. Since it is possible to expand the area where raw SL materials can be supplied, the present invention has been completed.

According to the present invention, "the amount of cement per 1 m ³ is
300 to 550 kg, water cement ratio (weight ratio) 0.6 to 1.4, fine aggregate cement ratio (weight ratio) within the range of 0.5 to 4, base cement mortar per 1 m ³ of the fluidizing agent 2
.About.10 kg, thickening agent 0.5 to 5 kg and defoaming agent 0.3 to 1 kg and kneaded in a forced kneading mixer for 0.5 to 2 minutes to obtain a cement mortar composition having a flow value of
A method of constructing a self-smooth cement mortar composition, which comprises casting and hardening when it is within a range of 20 to 35 cm ”is a gist.

The details of the present invention will be described below. The self-smooth cement mortar composition of the present invention (hereinafter simply referred to as the composition of the present invention) comprises a base cement mortar (hereinafter simply referred to as base mortar) and additives such as a fluidizing agent, a thickener and a defoaming agent. Composed. The base mortar constituting the composition of the present invention comprises cement, fine aggregate and water. As the cement, various kinds of cement such as ordinary Portland cement, early-strength Portland cement, moderate heat Portland cement, blast furnace cement, silica cement, fly ash cement, alumina cement, and jet cement can be used. As the fine aggregate, those used in general ready-mixed concrete production, or fine plaster for plastering can be used, and the particle size is 5
mm or less, preferably 2 mm or less, more preferably 1 mm or less.

The amount ratio of the above-mentioned materials in the base mortar constituting the composition of the present invention-the unit cement amount per 1 m ^{3 of the} base mortar, the water cement ratio and the fine aggregate cement ratio are water, cement for obtaining the base mortar. And the first set factor to determine the required amount of fine aggregate.

The unit cement amount is 1 m ^{3 of} base mortar.
This is the amount of cement used per unit. The unit cement amount in the base mortar used in the composition of the present invention is preferably in the range of 300 to 550 kg / m ³ . If it is less than 300 kg / m ³ , the fine aggregate cement ratio becomes large, the flow value of the cement mortar composition becomes small, the level accuracy of the formed hardened body deteriorates, and the strength becomes small. On the other hand, 550 kg / m
^When it exceeds ³ , cracks occur in the formed cured body.

The water-cement ratio is represented by the weight ratio W / C of the unit amount of water W and the unit amount of cement C, and is a factor that affects the fluidity of the composition of the present invention and the strength of the cured product. The water-cement ratio (weight ratio) in the base mortar used in the composition of the present invention is preferably in the range of 0.6 to 1.4. When it is less than 0.6, the fluidity of the cement mortar composition is low, and the level accuracy of the finished surface of the formed cured body is lowered. on the other hand,
If it exceeds 1.4, breathing or aggregate sedimentation occurs, and the hardened body thus formed causes white sinter and cracks.

The fine aggregate cement ratio (weight ratio) is the weight ratio S / C of the weight S of the fine aggregate used and the unit cement amount C.
And affects the fluidity and the state of the finished surface of the composition of the present invention. The fine aggregate cement ratio (weight ratio) in the base mortar used in the composition of the present invention is 0.5 to
A range of 4 is good. If it is less than 0.5, cracks occur in the formed cured body. On the other hand, when it exceeds 4, the fluidity of the cement mortar composition is reduced, and the level accuracy of the finished surface of the formed cured body is reduced.

To obtain the composition according to the invention, fluidizers, thickeners and defoamers are added to the base mortar. The superplasticizer has a function of increasing fluidity without increasing the amount of water mixed in the composition of the present invention, and includes a melamine formalin condensate sulfonate, a lignin sulfonate,
Examples thereof include polyalkylallyl sulfonate, β-naphthalene sulfonic acid aldehyde condensate, polycarboxylate, and the like, and these can be used alone or in combination of two or more.

The addition amount of the fluidizing agent is slightly different depending on the kind, but is preferably in the range of 2 to 10 kg per 1 m ^{3 of} the base mortar. If the added amount is less than 2 kg, the effect of improving the fluidity cannot be obtained, and the level accuracy of the finished surface of the formed cured body is reduced. On the other hand, when it exceeds 10 kg, breathing and sedimentation of aggregate occur, and the hardened body thus formed produces white sinter.

The thickener has a function of preventing the generation of breathing water and the sedimentation of aggregate when the composition of the present invention is cast and spread, and cellulose ethers such as methyl cellulose, ethyl cellulose, hydroxyethyl cellulose and carboxymethyl cellulose. , Polyacrylamide,
Examples include various water-soluble polymers such as polyethylene oxide, polyvinyl alcohol, and casein, and these can be used alone or in combination of two or more.

The addition amount of the thickening agent is slightly different depending on the kind and the molecular weight, but per 1 m ^{3 of} the base mortar,
The range of 0.5-5 kg is good. If the amount added is less than 0.5 kg, bleeding and aggregate sedimentation will occur, causing whitening in the formed cured product. On the other hand, if it exceeds 5 kg, the viscosity is increased and the fluidity is lowered, and the level accuracy of the finished surface of the formed cured body is lowered.

The air entrained when the fluidizing agent and the thickening agent are added to the base mortar and kneaded forms bubbles due to the surface-active action of these additives, so that a gas is formed on the surface of the formed cured product. The surface condition deteriorates due to the inclusion of bubble-like protrusions and pinholes in the trace of vaporized gas. Further, the strength of the cured body formed by curing while containing bubbles is lowered.

The defoaming agent has a function of preventing the occurrence of such a phenomenon, and various kinds of defoaming agents such as alcohol-based, polyol-based, fatty acid ester-based, ethylene oxide-propylene oxide-based, and silicon-based defoaming agents are used. And these can be used alone or in combination of two or more.

The amount of defoaming agent added varies slightly depending on the type, but is 0.3 to 1 kg per 1 m ^{3 of} the base mortar.
The range is good. If the amount added is less than 0.3 kg, air bubbles remain in the formed cured product, while if it exceeds 1 kg, the defoaming effect does not increase so much, which is economically disadvantageous. Incidentally, as additives other than the above, a curing accelerator, a curing retarder, a shrinkage reducing agent,
A swelling agent or the like can be used if necessary.

As described above, a base mortar consisting of cement, fine aggregate and water, and a fluidizing agent, a thickener and a defoaming agent added to the base mortar are used in a material mixing ratio within the range specified in the present invention. The composition obtained by appropriately combining the addition amount, kneading under the conditions specified in the present invention,
A composition of the invention is obtained.

The kneading device used in the method of the present invention is as follows:
A forced kneading mixer with good kneading performance is used. As the forced kneading mixer, a pan type or a pug mill type is used, and a pug mill type is preferable. In particular, it is preferable to use a multi-screw type mixer such as a twin-screw forced kneading mixer.

The kneading time is preferably 0.5 to 2 minutes.
If the kneading time is less than 0.5 minutes, the fine aggregate is not sufficiently dispersed in the kneaded product, and the formed aggregate of fine aggregate remains. Even if the kneaded product in such a state is cast and cast, a smooth floor surface cannot be obtained. On the other hand, when the kneading time exceeds 2 minutes, the kneaded product adheres to the inner wall of the kneading device or the stirring blades, which makes it difficult to wash and remove the kneaded product after discharging the kneaded product from the kneading device. In such a state, when the production equipment is shared with the ready-mixed concrete or the ready-mixed mortar, the SL material component remaining in the production equipment adversely affects the quality of the batch-purpose ready-mixed ready-mixed concrete or the ready-mixed mortar. Further, when the kneading time exceeds 2 minutes, the amount of air mixed in increases, the amount of the defoaming agent added in the above range does not allow the defoaming to be completed, and the fluidity of the kneaded product is lowered, so that a smooth floor surface can be obtained. Cannot secure the flow value.

The flow value (hereinafter referred to as F) when casting the composition of the present invention must be in the range of 20 to 35 cm. Flow value F when casting the composition of the present invention
However, if it is less than 20 cm, protrusions remain on the surface of the formed cured body, and the level accuracy of the finished floor surface deteriorates. On the other hand, 35 cm
If it exceeds, breathing and sedimentation of aggregates will occur, and whitening will occur in the cured body.

Examples of embodiments of the construction method using the composition of the present invention are shown below, but the invention is not limited thereto. The composition of the present invention can be produced not only in a production facility dedicated to ready-mixed SL materials but also in a production facility for ready-mixed concrete, and is generally used when transporting ready-mixed concrete to the site of civil engineering / construction work. Can be accepted by mixer trucks. The composition of the present invention produced in a mixer plant of a ready-mixed concrete factory under the conditions specified in the present invention and transported to a construction site by a mixer truck is used within a range of the F value specified in the present invention by using a mortar pump or the like. And spread it to the construction site and smooth it using a surface leveling tool such as a register mark.
A hardening mode is possible.

[0025]

The method of the present invention has the following effects. 1) Since the work of handling powders and heavy objects at the construction site is greatly reduced, the work efficiency is improved and the pollution of the work environment due to dust can be prevented. 2) Since it is possible to prevent the increase in the adhesiveness of the kneaded material to the inner wall of the kneading device or the stirring blades and to easily wash and remove the kneaded material, it is possible to manufacture it by sharing the ordinary ready-mixed concrete manufacturing equipment. The degree of freedom of the area where the composition of the present invention can be used is large, and the area where the composition can be supplied can be expanded. 3) Dispersion of fine aggregate is good, smooth and good hardened body is formed without white fluff / protrusions and bubble traces, and a finished floor surface with good level accuracy can be easily obtained. 4) Compared with the conventional construction method, it has become possible to significantly reduce labor during construction when building a building floor and stabilize the quality of the finished floor surface.

[0026]

EXAMPLES The present invention will be specifically described below with reference to Examples and Comparative Examples. The present invention is not limited to the following examples unless it exceeds the gist. Examples 1-5 and Comparative Examples 1-19. Various mortar compositions were obtained under the material mixing ratios and kneading conditions shown in Table 1. 0.1 m ³ of the obtained mortar composition,
At the flow value F shown in Table 1, a mortar pump was used to cast a 20 mm thick layer on 5 m ² of concrete slab, and it was leveled with a dragonfly and naturally cured.

Table 1 shows the physical properties and properties of the tested mortar compositions and cured products thereof. The main materials used in the test are as follows. -Cement ... Ordinary Portland cement-Fine aggregate ... Plastering sand for building-Additive a ... Fluidizing agent "SMF-PD" (manufactured by Nissan Chemical Industries, Ltd.)-〃 b ... Thickener "hi-Metroze 90SH 30000" ( Shin-Etsu Chemical Co., Ltd.) 〃 c ... Defoamer "SN Deformer 14 HP" (San Nopco Co.)

The equipment shown in the column of kneading equipment in Table 1 and used for kneading by adding the additive to the base mortar is as follows. Kneading device A… Bread type forced kneading mixer (manufactured by Koyo Kikai Sangyo Co., Ltd., capacity 1 m ³ ) 〃 B… Biaxial forced kneading mixer in the ready-mixed plant (Nippon Construction Machinery Co., Ltd., capacity 3 m ³ ).

The method of measuring or testing each evaluation item shown in Table 1 is as follows.・ Washability of mortar composition… When removing the mortar composition by washing from inside the kneading device, it is “easy” if it can be removed by running water, and “difficult” if pressurized water (0.1 kg / cm ² or more) is required. It was classified as ". -State of mortar composition slurry ... The presence or absence of a lump of fine aggregate having a diameter of more than 5 mm was visually observed and determined.・ Flow value: F is the right angle of the circle formed by filling the flow cone with the sample and lifting the flow cone vertically according to the test method specified in JIS R5201, and spreading the sample flowing out in a circular shape and standing still. The diameter in two directions was measured and expressed as the average value.・ Breathing of mortar composition, presence of aggregate sedimentation ...
It was judged by observing the condition after 3 hours from kneading.

Surface state of the cured body (white flower, protrusions and air bubble traces): The mortar composition is cast in a thickness of 20 mm, and the temperature is 20 ° C.
After 7 days at RH 60%, it was judged visually and visually.・ Whether you can walk lightly the next day ... Cast the mortar composition in a thickness of 20 mm, and after 12 hours at 20 ° C and RH60%, step on it with a shoe with a rubber sole, and check whether a mark of the sole is left on the surface of the cured product. It was judged by visual observation.・ Level accuracy of the hardened material: The mortar composition is cast on a concrete slab (0.5 m × 5 m) in a thickness of 10 mm and smoothed using a register mark, and the level accuracy of the surface of the hardened material formed is measured using a level. It was measured. -Compressive strength of the cured product: The sample was poured into a mold of 40 x 40 x 160 mm, demolded after curing, cured at 20 ° C and RH 60%, and uniaxial compressive strength was measured at 4 weeks of age.・ Presence of cracks ... Concrete slab with mortar composition
(1m x 1m) Cast on 20mm thick, 20 ℃, RH60%
After 28 days, it was visually observed and judged.

[0031]

[Table 1]

The meanings of the symbols in the columns of each evaluation item shown in Table 1 are as follows.・ Cleanability of mortar composition ○… easy, ×… difficult; ・ Agglomerate of fine aggregate ・ Breathing ・ Aggregate sedimentation ・ White flower ・
Protrusions, bubble marks, cracks: ○…
No, ×… Yes; ・ Light walking the next day ○… Yes, ×… No; ・ Level accuracy ○… 1/300 or less, ×… 1/300 or more;

In each of Examples 1 to 5, which were tested under the conditions satisfying the requirements of the present invention, a smooth and good cured product was formed, and a floor surface with good level accuracy was obtained. On the other hand, Comparative Example 1
Nos. 6 to 6 have the same material mixing ratio of the base mortar,
-11 is the case where the addition amount of the fluidizing agent, the thickener or the defoaming agent added to the base mortar deviates from the range specified in the present invention, and Comparative Example 12 uses these additives. In all cases, satisfactory results were not obtained.

From the viewpoint of composition, Comparative Examples 13 to 17 have the material mixing ratios defined in the present invention corresponding to Examples 1 to 5, respectively, but the kneading time at the time of preparation of the mortar composition is the same in the present invention. If it is out of the specified range,
None of them yielded satisfactory results. Comparative Examples 18-19
In the case where the flow value when casting the mortar composition was out of the range specified in the present invention, no satisfactory result was obtained.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Internal reference number FI Technical display location C04B 24:18 B 2102-4G 24:38) D 2102-4G (72) Inventor Miyazaki Matsumi Tokyo 1-5-1, Marunouchi, Chiyoda-ku, Nitto Kagaku Kogyo Co., Ltd. (72) Inventor Takeshi Mashita 5-16-7 Sugamo, Toshima-ku, Tokyo Incorporated in Mashita Kenzai Kogyo (72) Inventor Hiroshi Ito Kanagawa 3 Try Industry Co., Ltd. at 4239 Minamiyamada-cho, Kohoku-ku, Yokohama-shi, Japan

Claims (1)

[Claims] 1. The amount of cement per 1 m ³ is 300 to 550 k.
g, water cement ratio (weight ratio) 0.6 to 1.4, fine aggregate cement ratio (weight ratio) within the range of 0.5 to 4, base cement mortar per 1 m ³ of the fluidizing agent 2 to 10 kg, thickener When 0.5 to 5 kg and 0.3 to 1 kg of an antifoaming agent are added and kneaded in a forced kneading mixer for a range of 0.5 to 2 minutes, the obtained cement mortar composition has a flow value within a range of 20 to 35 cm. A method of applying a self-smooth cement mortar composition, which comprises casting and hardening.