JP2005213085A - Ultra-lightweight mortar - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide ultra-lightweight mortar having sufficient strength and easy to finish plastering by holding softness for long after kneading. <P>SOLUTION: This ultra-lightweight mortar comprises water, cement, lightweight aggregate of ≤1.0 absolute-dry specific gravity in an absolute dry condition or prescribed amount water-absorbed condition, a polycarboxylic acid-based water reducer or a water reducer having dispersibility equal to or higher than that of the polycarboxylic acid-based water reducer, an inorganic material finer in size than the average particle size of the cement, and an expansive admixture. Thereby pot life after kneading can be extended, transportable distance can be elongated and time to finish plastering can be enough allocated. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an ultralight mortar using a lightweight aggregate having an absolute dry specific gravity of 1.0 or less. Further, all materials other than the blended water can be stored in a mixed state as a premix material, and the blended water is given in the field. It is an ultralight mortar that can be applied only by itself, is easy to knead, maintains softness for a long time, has little quality difference due to kneading time, has little change in specific gravity, is suitable for long transportation times, and is easy to plaster.

  In lightweight concrete using lightweight aggregates, lightweight aggregates are usually used in a predetermined water absorption state by prewetting, but a technology that can be used in a dry state without wetting the lightweight aggregates has been developed. (See Patent Document 1). In the lightweight concrete disclosed in Patent Document 1, by using a highly dispersible water reducing agent, it is possible to realize a lightweight concrete having properties equivalent to those of a lightweight concrete that performs conventional prewetting.

Japanese Patent No. 3382442

  By the way, for example, when an ultralight mortar using a light aggregate (JIS A 5002) having an absolute dry specific gravity of less than 1.0 is used for production, in the production method using the water reducing agent as described above, the flow value after placing is set. There is a problem that the decrease in the unit volume is large and the change in the unit volume mass is large. In order to avoid this problem, by increasing the unit water amount or increasing the amount of water-reducing agent used, it is possible to avoid a rapid decrease in the flow value if the flow value immediately after placement is increased. The mortar surface sinks and cannot be plastered for surface finishing. When the flow value is such that plastering is possible, the unit volume mass becomes heavier and wrinkles are generated by the movement of the iron. If wrinkles are easy to make, construction of a large area is not practical. In this way, the ultra-light mortar that is in the conventional dry state and uses a lightweight aggregate with an absolute dry specific gravity of 1.0 or less has a limited transportable time, and it is difficult to finish plastering. It was. As described above, it has been a problem to increase the transportable time after kneading and improve the plastering efficiency and workability.

  In addition, as a problem in handling materials at the site, very light aggregates with an absolute dry specific gravity of 1.0 or less are easily scattered due to the influence of wind and other factors when measured at the site. Because of the specific gravity difference, it takes time to knead. As described above, it has been a problem to reduce the on-site weighing work, still facilitate kneading, and improve workability. There is also a problem that the initial strength after placement is slow.

  The present invention has been made in view of such a situation, and is easy to knead and place on site, has a reduced flow value after placement, has little change in unit volume mass, and has a long transportable time. An object of the present invention is to provide an ultralight mortar having a feature that a plaster finish area is large because a flow value holding time for plastering work is long and wrinkles are difficult to be formed.

  As a result of intensive studies for obtaining an ultralight mortar having a long plasterable finish area and having a long influence on the kneading time, which has a long transportable time that could not be obtained conventionally, It has been found that the conventional problems described above can be solved at once by a composition comprising an inorganic material finer than the average particle size, an organic agent, and an expanding agent, and the present invention has been completed.

  The composition of the present invention comprises water, cement, a lightweight aggregate having an absolute dry specific gravity of 1.0 or less in an absolutely dry state or a predetermined water absorption state, a water reducing agent, an inorganic material finer than the average particle size of the cement, The water reducing agent contains a swelling agent, and the water reducing agent has a dispersibility equivalent to or higher than that of a polycarboxylic acid water reducing agent or a polycarboxylic acid water reducing agent.

  As an organic agent, it is preferable to add at least one or more water-soluble substances mainly composed of acrylic, acrylic styrene copolymer, and acrylic silicon copolymer.

  In the configuration of the invention described above, the inorganic material is preferably at least one of silica fume, blast furnace slag fine powder, and fly ash fine powder.

  The water reducing agent is preferably used in an amount of 0.02% by mass or more of the cement mass as a solid content.

  It is preferable that the lightweight aggregate absorb water from an absolutely dry state to about 50% of the water absorption rate of the lightweight aggregate. At this time, the water cement mass ratio is preferably 30% or more.

  It is preferable to use a premix material in which all materials other than water are solids and the solids are mixed in advance.

The unit volume mass after kneading is preferably 1.2 t / m ³ or less.

  According to the present invention, in terms of construction, since the pot life after kneading could be extended, the distance that can be transported, the time for plastering finishing work can be increased, and plastering finishing etc. There is an effect that finishing work becomes easy. Since the change in physical properties due to the elapsed time during kneading can be reduced, a continuous operation can be performed by a small mixer without worrying about the kneading time. As a result, the construction period can be shortened and the cost can be reduced. In addition, the strength is higher than the specific gravity, and the initial strength is also high.

  The ultralight mortar of the present invention can impart fluidity and is also excellent in adhesion performance. Plastering can be done on large or thin sides.

  The ultralight mortar of the present invention has a low water absorption after curing. Furthermore, in order to prevent water absorption, it is also suitable for applying a water repellent to the surface. It is also possible to use a water repellent as part of the prepared water.

  The ultralight mortar of the present invention is imparted with fluidity and excellent adhesion performance. For this reason, plastering can be performed on the side of a large area with an arbitrary layer thickness.

  The ultralight mortar of the present invention has a low water absorption after curing. Furthermore, in order to prevent water absorption, it is also suitable for applying a water repellent to the surface. It is also possible to use a water repellent as part of the prepared water.

  The ultralight mortar of the present invention is excellent in heat insulation and sound absorption. Since there is little change in physical properties due to the length of the kneading time, it is easy to add any material such as a colorant.

  Since the super lightweight mortar of the present invention is suitable for natural curing and steam curing, it is also suitable for secondary products. Furthermore, it is also suitable for secondary products with a large area and thickness.

  The ultralight mortar of the present invention has good cost performance with respect to the obtained performance.

  The ultralight mortar of the present invention is suitable for mixing and supplying all the materials except the blended water as a solid content. The mixed product is also suitable for long-term storage. Use of mixed products can improve work efficiency on site.

  Since the ultralight mortar of the present invention can be used as a premix material, it can be easily applied on site and has excellent durability even after curing.

    Hereinafter, the ultra-light mortar of the present invention will be described with reference to examples. The present invention relates to water measured at a predetermined water cement mass ratio and added at the time of kneading, cement, a lightweight aggregate having an absolute dry specific gravity of 1.0 or less in an absolutely dry state or a predetermined water absorption state, and a polycarboxylic acid type. A water reducing agent or a water reducing agent having dispersibility equivalent to or higher than that of a polycarboxylic acid-based water reducing agent, an inorganic material finer than the average particle diameter of the cement, and an expansion agent are contained. The materials and production thereof will be described below, and the effects brought about by the present invention will be mentioned in the examples (experimental examples).

[material]
Hereinafter, the material which comprises the ultralight mortar of this invention is demonstrated individually.
As the cement used for the ultralight mortar, other than ordinary Portland cement, early-strength Portland cement, belite cement, sulfate-resistant cement, blast furnace cement, three-component cement, mixed cement, and the like can be used.

  The water reducing agent used for the ultralight mortar is preferably a polycarboxylic acid-based water reducing agent. Specific examples of this polycarboxylic acid-based water reducing agent include composites (calcium-based) whose main component is a polycarboxylic acid ether. Commercially available products can also be used suitably, for example, trade name SP-8HE manufactured by NM, trade name Mighty 2000TH manufactured by Kao Corporation, and trade name Sea Cament 1200N manufactured by Nippon Seika Co., Ltd. 2500F etc. are mentioned. Furthermore, the product name EV2000, 50E200 by Nippon NS Co., Ltd. marketed as a powder form etc. are mentioned.

  Water reducing agents having other compositions can also be used. In this case, it is necessary to have a property of imparting dispersibility equivalent to or higher than that of the polycarboxylic acid-based water reducing agent. As an example, a carboxyl group-containing polyether water reducing agent is suitable. As a commercially available product, for example, trade name CAD-8000 manufactured by Kao Corporation can be used in the present invention.

The rate of addition of the water reducing agent in the present invention varies depending on the amount of water used relative to the added amount of cement and inorganic material, organic agent, cement and inorganic material, organic agent, and expansion agent added, for example, 0. It is 2 to 9.0 liter / m ³ , preferably 0.3 to 7.0 liter / m ³ . In the case of powder, it is preferably 0.04 to 2.5 kg / m ³ , preferably 0.05 to 2.0 kg / m ³ .

As the inorganic material used for the ultralight mortar of the present invention, a material mainly composed of SiO ₂ is preferably used. Specific examples of the silica fume include micro silica manufactured by Elchem, 940U, and 940EU. Blast furnace slag fine powder or fine powder obtained by pulverizing ceramics or fly ash is also preferably used. Furthermore, these fine powders can be added simultaneously, not only alone. For example, it is also effective to use silica fume and blast furnace slag fine powder, or a combination of silica fume, slag fine powder and fly ash fine powder.

  The lightweight mortar composition of the invention can also wet the lightweight aggregate as necessary, and can be used even in a water absorption state up to about 50% of the water absorption rate of the lightweight aggregate.

  The kind of lightweight aggregate with an absolute dry specific gravity of 1.0 or less used for ultralight mortar includes pearlite as non-structural lightweight aggregate, but it is not limited to this, and depending on the purpose Various choices such as those simulating pearlite, obsidian, and pine stones. Natural lightweight aggregates and artificial lightweight aggregates can also be used in combination. Specifically, artificial light-weight fine aggregate obtained by foaming natural pumice crushed sand and obsidian produced in Haruna with a foaming agent can also be used. Different types of artificial lightweight fine aggregates can be used in combination. Specifically, artificial lightweight fine aggregates made of nacreous foam and artificial lightweight fine aggregates made by foaming glass can be used. It can be used as a ceramic filler of hollow microspheres in an artificial lightweight fine aggregate obtained by foaming, and these can be used in various types. Furthermore, it can be used together in a form in which a fine aggregate in an almost dry state is mixed with a fine aggregate in a wet state.

  It is also preferable to use it as an organic agent used in the ultralight mortar composition in order to increase the water retention of mortar mainly composed of acrylic or acrylic copolymer such as acrylic, acrylic styrene copolymer and acrylic silicon copolymer during kneading.

  The other additive materials used for the ultralight mortar can be the same as the conventional additive material and are not particularly limited. For example, an expanding agent, an AE agent, a dimensional stabilizer, and a foaming agent can be added as appropriate. Further, a plurality of these can be added. That is, it can be selected, used together, or combined depending on the purpose and application.

[Manufacturing]
Light weight mortar using aggregate with an absolute dry specific gravity of 1.0 or less according to the present invention is kneaded after materials are put into a mixer, and mixed water and water reducing agent are added, as in conventional light weight mortar. It is preferable to carry out. Moreover, it is also preferable to mix all the materials except mixing water and to store as a premix material. In this case, an ultralight mortar with an appropriate blend can be manufactured by adding a predetermined amount of blended water to the premix material and kneading. In this case, a known concrete mixer such as a forced biaxial type, a pan type, or a tilting cylinder type can be used.

A known curing method and apparatus can be employed as the curing means. For example, steam curing with a predetermined integrated temperature can be employed, thereby preventing initial cracks and the like.
Hereinafter, the ultralight mortar of the present invention will be described with reference to examples.

  According to the blending ratio shown in Table 1, a conventional lightweight mortar and an ultralight mortar (Example 1) as comparative examples were produced. The materials used in this example are high-strength cement manufactured by Taiheiyo Cement Co., Ltd. as the cement, silica fume of trade name 940-U manufactured by Elchem Japan Co., Ltd. as the inorganic material, and crystal clay ( An artificial light-weight fine aggregate manufactured by the company, trade name G LIGHT was used. As the organic agent, a reagent name VP-A manufactured by Nippon Seika Co., Ltd., whose main component is acrylic polymerization, was added to the blended water. The reagent name P-1 (special sodium sulfate type | system | group) by Nippon Sika Co., Ltd. was added as a swelling agent. As the water reducing agent, trade name Seikament 2500F which is a polycarboxylic acid-based high performance AE water reducing agent manufactured by Nippon Seika Co., Ltd. was used. As the AE agent, a product name Sika AER-G manufactured by Nippon Sika Co., Ltd. was used.

  In accordance with the formulation shown in Table 1, each material was put into a mixer and kneaded, then blended water and a water reducing agent were added, followed by main kneading, and a lightweight mortar (comparative example) and an ultralight mortar (Example) 1) was produced.

  For the obtained lightweight mortar (comparative example) and ultralight mortar (Example 1), physical properties and plastering properties after 10 minutes of kneading were examined. The results are shown in Table 2.

  Further, each lightweight mortar and ultralight mortar were placed on a mold (4 × 4 × 16 cm) to obtain a specimen, and the compressive strength was measured. The results are shown in Table 3.

  Light weight mortar (comparative example) and ultralight mortar (Example 2) were produced according to the blending ratio shown in Table 4. The material used in this example is Sumitomo Osaka Cement Co., Ltd.'s early-strength cement as the cement, Elchem Japan Co., Ltd., trade name 970-U silica fume as the inorganic material, and fine aggregate as Sakai Perlite Co., Ltd. A mixture of an artificial light-weight fine aggregate with a trade name of Fyolite and Taiheiyo Cement Co., Ltd. with a trade name of Microcells was used. The organic agent was made by Nippon Sika Co., Ltd., whose main component is acrylic polymerization, and the reagent name VP-A was added to the blended water. As the water reducing agent and the AE agent, polycarboxylic acid-based high performance AE water reducing agents manufactured by NM Co., Ltd., trade names SP-8HE and 775S were used. As the swelling agent, trade name EXPAN M manufactured by Taiheiyo Cement Co., Ltd. was used. In addition, Neolite Kosan Co., Ltd. brand name Kenacell S was used as a fiber material.

  In accordance with the formulation shown in Table 4, each material was put into a mixer and kneaded, then blended water and a water reducing agent were added, followed by main kneading, ultralight mortar (comparative example) and ultralight mortar (implemented) Example 2) was prepared.

  For the obtained ultralight mortar (comparative example) and ultralight mortar (Example 2), physical properties and plastering properties after 5 minutes of kneading were examined. The results are shown in Table 5. It was confirmed that the physical properties of the ultra-light mortar (Example 2) did not change greatly even when continuously kneaded for 30 minutes.

  Further, each lightweight mortar and ultralight mortar were placed on a mold (4 × 4 × 16 cm) to obtain a specimen, and the compressive strength was measured. The results are shown in Table 6.

  Light weight mortar (comparative example) and ultralight mortar (Example 2) were produced according to the blending ratio shown in Table 7. All materials were solid and used as premix material. That is, only the blended water was added during kneading. In addition, the material used in the present example is a high-strength cement manufactured by Mitsubishi Materials Corporation as cement, fine powder obtained by pulverizing fly ash manufactured by Chubu Electric Power Co., Ltd. as an inorganic material, and fine aggregate is perlite A mixture of an artificial light-weight fine aggregate with a trade name of Fyolite manufactured by Co., Ltd., and Taiheiyo Cement Co., Ltd. with a trade name of Microcells was used. As the organic agent, a reagent name VP-B manufactured by Nippon Seika Co., Ltd., whose main component is acrylic polymerization, was used. As a water reducing agent, a product made by Erotex Co., Ltd., a polycarboxylic acid-based high-performance water reducing agent, trade name EV2000 was used, and as a swelling agent, a product of Nippon Sika Co., Ltd., a special sodium sulfate-based reagent name P-1 was used. The product used was Palchip, a trade name of polypropylene fiber from Ebara Corporation.

  In accordance with the formulation shown in Table 7, each material was put into a mixer and kneaded, then blended water and a water reducing agent were added, followed by main kneading, ultralight mortar (comparative example) and ultralight mortar (implemented) Example 3) was prepared.

  For the obtained ultralight mortar (comparative example) and ultralight mortar (Example 2), physical properties and plastering properties after 5 minutes of kneading were examined. The results are shown in Table 8.

  Further, each lightweight mortar and ultralight mortar were placed on a mold (4 × 4 × 16 cm) to obtain a specimen, and the compressive strength was measured. The results are shown in Table 9.

  As can be seen from Table 9, the ultralight mortar (Example 3) was found to have higher strength and higher initial strength than the specific gravity. Moreover, since the distance which can be conveyed after kneading | mixing can be taken long and the work possible time for plastering finishing work can be taken long, workability | operativity, such as surface finishing, is easy to improve. Since there is little change in physical properties due to the length of the kneading time, continuous operation can be performed without worrying about the kneading time by a small mixer. Therefore, it is possible to shorten the construction period and cost saving of the finishing process such as plastering work.

In addition, the ultralight mortar of the present invention can secure a sufficient time for plastering work because the distance that can be transported after kneading can be long even if the amount of unit cement is large, for example, about 400 kg / m ³ is used. There are also advantages.

Claims (8)

  It contains water, cement, a lightweight aggregate having an absolute dry specific gravity of 1.0 or less in an absolutely dry state or a predetermined water absorption state, a water reducing agent, an inorganic material smaller than the average particle size of the cement, and an expansion agent. The water reducing agent is a polycarboxylic acid-based water reducing agent, or an ultralight mortar characterized by having dispersibility equivalent to or higher than that of a polycarboxylic acid-based water reducing agent.   2. The ultralight mortar according to claim 1, wherein at least one water-soluble organic agent mainly composed of acrylic, acrylic styrene copolymer and acrylic silicon copolymer is added.   The ultralight mortar according to claim 1, wherein the inorganic material is at least one of silica fume, blast furnace slag fine powder, and fly ash fine powder.   2. The ultralight mortar according to claim 1, wherein the amount of the water reducing agent used is 0.02% by mass or more of the cement mass as a solid content.   The lightweight mortar composition according to claim 1, wherein the lightweight aggregate is absorbed from an absolutely dry state to about 50% of the water absorption rate of the lightweight aggregate.   The ultralight mortar according to any one of claims 1 to 5, wherein a water cement mass ratio is 30% or more.   2. The ultralight mortar according to claim 1, wherein all materials other than water are solid contents, and are made of a premix material in which the solid contents are mixed in advance. The ultralight mortar according to claim 1, wherein the unit volume mass after kneading is 1.2 t / m ³ or less.