JP2003119063A - Low-shrinkage lightweight mortar and surface preparation method using low-shrinkage lightweight mortar - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide low-shrinkage lightweight mortar which is used in coating the highly rigid and flat ground surfaces of, for example, cast-at-site concrete, precast concrete members, concrete blocks, and bricks, with the cement mortar, exhibits a high follow-up characteristic to the dry, moist, warm and cold movements of a body having high rigidity, can be easily smoothed by about twice up to 3 to 25 mm of a coating thickness after under-rubbing in the application, is high in the adhesion to the body after curing, is high in the adhesion to coating joint mortar as well, is low in shrinkage and water absorption, and can prevent cracking by curing and drying and the infiltration of external rain water and the surface preparation method using this low-shrinkage lightweight mortar. SOLUTION: This low-shrinkage lightweight mortar is 1.1 to 1.9 in the unit volume mass of the composition, exhibits the low shrinkage, low water absorption and high adhesion, can be easily smoothed, has the flexibility to follow-up the hot, cold, dry and wet movements of the body, etc., after curing and hardly cracks.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is used for applying cement mortar to a highly rigid flat substrate such as cast-in-place concrete, precast concrete members, concrete blocks, bricks, etc. It shows high followability to hot and cold movements, and can be easily smoothed by 2 times after under-rubbing after coating, about 3 to 25 mm in thickness, has high adhesion with the body after curing, and has good mortar compatibility. The present invention relates to a low-shrinkage lightweight mortar that has high adhesion, low shrinkage / low water absorption, and can be prevented from cracking due to curing / drying and intrusion of external rainwater, and a base adjustment method using a low shrinkage lightweight mortar.

[0002]

2. Description of the Related Art When cement mortar is applied to a highly rigid flat substrate such as cast-in-place concrete, precast concrete members, concrete blocks, bricks, etc., it has the ability to follow the movement of hot and cold, dry and wet movements of a highly rigid body. Adhesiveness is important, and there was also a problem in construction that the construction method was different from adjustment of thickening unevenness to thinning with less unevenness as shown below.

In the case of thickening unevenness adjustment, the base adjustment method is applied in three steps (bottom, middle, and top coating) and the thickness of each step is 7 mm or less. Ground preparation method constructed with lightweight sand mortar. A base conditioning method in which a lightweight sand mortar is undercoated and then cement mortar is applied. When there is little unevenness, a ground preparation method that uses cement paste.

[0004]

However, each of the above-mentioned conventional construction methods (1) to (3) has the following problems in construction and quality.

In the case of the above-mentioned construction method: (Problems in construction) In the construction method used for adjusting a large uneven surface, thick coating cannot be applied at once in the construction method; Since it is divided into two parts, the work is troublesome and the construction cost is high. Further, it is necessary to strictly control the time (curing) interval between each coating and the next coating so as not to cause adhesion failure between the three mortar layers. (Problem in Quality) As described above, when the curing time is not strictly controlled, defective adhesion between mortar layers is likely to occur.

[0006] In the case of the above-mentioned construction method: (Problems in construction) Cement and adhesive (ethylene vinyl acetate-based / acrylic-based / SBR-based resin emulsion) are kneaded and mixed in the on-site formulation, and are lightweight. However, it cannot be thickened, and there is a type for external use, but it is not currently approved as a tile base in the construction work specifications. (Problems in quality) Although the quality is stable when used according to the standard method specified by the manufacturer, it is difficult to show stable performance if the on-site mixture control is neglected because the mixture covers several types. Moreover, due to the smoothness of the finish, the amount of shrinkage of the mortar is large because the proportion of cement is large.

In the case of the above-mentioned construction method: (Problem in construction) Since the cement sand mortar is used as the base of the lightweight sand mortar, it is necessary to control the construction interval. If the process interval is not sufficient, the mortar floats and shrinks cracks. Easy to enter. Cement mortar also needs an admixture, and kneading must be controlled. (Problems in quality) If the composition and construction management of cement mortar is not performed sufficiently, the performance such as adhesion will not be stable,
Uncertain.

In the case of the above-mentioned construction method: (Problem in construction) It can be used for construction only when there is little unevenness, and is unsuitable when there is large unevenness. (Problems on quality) Stable performance can be obtained for already prepared products, but it is difficult for on-site prepared products. It cannot be thickened more than 10mm.

[0009]

The present invention has been proposed in view of the above, and the low-shrinkage lightweight mortar composition has a unit volume mass of 1.1 to 1.9 and has a low shrinkage, a low water absorption, and a high The present invention relates to a low-shrinkage, lightweight mortar characterized by having an adhesive force, capable of being easily smoothed, having flexibility to follow the movement of a skeleton or the like after curing, and being resistant to cracking.

Further, the low-shrinkage lightweight mortar of the present invention has a high ability to follow a dry / humidity / warm-cooling movement, and can be easily smoothed during construction up to 3 to 25 mm after rubbing in about twice. It is characterized in that it has a large adhesive force with the body after curing, and is suitably used for the undercoat preparation method. Further, it can be used in other methods other than the base conditioning method as well as other general cement mortars, it has excellent adhesion to the base, small drying shrinkage, and long-term stability. Furthermore, since the low-shrinkage lightweight mortar of the present invention is a one-powder type pre-mixed mortar, it is possible to prevent mismeasurement of cement and aggregate, resin, etc. when kneading the mortar as a ground control agent in the ground control method, and it is always stable. The obtained quality can be obtained, and the workability of transporting and kneading materials on site is improved. Young's modulus is small and dry
Since it can follow hot and cold movements, it is effective in preventing peeling and peeling of finishing materials (tiles, etc.). Also, since it is lightweight, it has good workability during application. In addition, it has low water absorption and water permeability, and is highly waterproof.

In the above-mentioned base adjustment method, the description was given as a base adjustment material, but as an application, a coating base, waterproof mortar,
It can also be applied to filled mortar.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION The development history of the present invention will be shown below, and the constitution of the present invention will be described in more detail. The present inventors aim to propose a low-shrinkage, lightweight mortar capable of solving the problems of the above-described conventional ground control method, and the unit volume mass of the composition at the time of construction is 1.1 to 1.9. ,
More preferably, it is 1.5 to 1.8, exhibits low shrinkage, low water absorption, high adhesive force, can be easily smoothed, and has flexibility to follow the movement of hot, cold, dry and wet of the body after curing. It has been found that a low-shrinkage, lightweight mortar that has a crack resistance and does not easily crack is suitable for the purpose. When the unit volume mass of the composition at the time of construction is less than 1.1, the composition components are greatly limited, and it is difficult to obtain a composition satisfying well-balanced performance and characteristics. Moreover, the unit volume mass is 1.9.
If it is larger than the above range, it becomes particularly difficult to apply it, and it is necessary to perform the application in several times as in the conventional case.

Regarding the aforementioned low shrinkage, specifically, the change in shrinkage is 0.15% or less, more preferably 0.05%.
It is the following. Regarding low water absorption, specifically, the absorption amount is 1.6 g or less, and more preferably 0.5 g or less.
For high adhesion, concretely, the adhesion strength is 0.7 N / mm
^{It is 2} or more, more preferably 1.5 N / mm ² or more.
The ability to be easily smoothed and easily smoothed using a trowel when finishing the surface is confirmed by workability. Flexibility and resistance to cracking are confirmed by compressive Young's modulus, bending strength, compressive strength, etc., and the compressive Young's modulus is 1.0 to 5.5 × 10 ⁻³ N / mm ² , more preferably 2 .5～4.0 a × 10 ^-3 N / mm ^2, bending strength of 3.0 N / mm ² or more, more desirably at 5.0 N / mm ² or more, the compressive strength is 5.0 N / mm ² or more, more preferably 10.0 N / mm ² or more, more desirably 20.0N / mm ² or more.

Furthermore, it is desirable that the following required quality (quality standard JIS A6916) is satisfied as characteristics other than these. Change in softness: ± 20 or less Impact resistance: No cracking or peeling Water permeability: 0.5 g or less Durability: No cracking, swelling or peeling, and adhesive strength of 1.
Greater than 0 N / mm ² Good followability with the body.

As the low-shrinkage lightweight mortar having such characteristics, one having the above-mentioned unit volume mass and the following composition ratio is used. Cement 17-52 wt%, lightweight aggregate 4.0-10 wt%, inorganic admixture 30-75 wt%
And short fiber 0.05 to 0.2 wt% and organic admixture 6.4
.About.11 wt%.

If a light weight mortar out of the above range of each component is used, the above quality cannot be obtained. For example, the compounding amount of cement is 17 to 52 wt%, but if it is less than 17 wt%, the compressive strength, water permeability, water absorption, etc. will be low,
When it is more than 52 wt%, the shrinkage and Young's modulus are bad. More preferably, the cement content is 30 to 50% by weight.
And

The blending amount of the lightweight aggregate is 4.0 to 10 wt.
%, But when it is less than 4.0 wt%, the specific gravity is heavy and the workability is poor, and when it is more than 10 wt%, the particle size distribution is poor, the water ratio is increased, and the shrinkage is increased, and the strength is reduced. To do. As this lightweight aggregate, EVA-
Organic aggregates such as calcium carbonate foam aggregate, styrene foam aggregate or the like, or perlite, glass foam aggregate, inorganic aggregates such as shirasu balloon can be used.

Further, the compounding amount of the inorganic admixture is 30 to 7
Although it is 2% by weight, if it is less than 30% by weight, the compressive strength and shrinkage increase, and the workability decreases. When it is more than 72 wt%, both Young's modulus and strength decrease, and setting time, curing failure and the like occur. As this inorganic admixture,
In addition to inorganic weight aggregates such as silica sand, shrinkage reducing agents, dolomite plaster, fly ash, blast furnace slag powder, calcium carbonate and the like can be used.

The blending amount of the short fibers is 0.05 to 0.2 wt%, but if it is less than 0.05 wt%, the effect of retaining the mortar before curing is lacking, and if it is more than 0.2 wt% during kneading. Takes in air and causes insufficient strength. As the short fibers, fiber-converging acrylic fibers, polyolefin-based reinforcing fibers, alkali-resistant glass fibers, carbon fibers,
Fibers such as vinylon fibers can be used. Fiber cut length is 2
The optimum thickness is 12 mm, but it may be determined depending on the coating thickness of the work.

The amount of the organic admixture is 6.4 to 1
Although it is 1 wt%, if it is less than 6.4 wt%, poor adhesion strength / shrinkage is deteriorated, and if it is more than 11 wt%, poor curing and workability are deteriorated. Examples of the organic admixture include vinyl acetate-beoba, ethylene vinyl acetate, re-emulsified powder resin such as acrylic resin, water-soluble thickener such as methyl cellulose, hydroxypropyl methyl cellulose, hydroxyethyl methyl cellulose, ethylene hydroxyethyl cellulose, naphthalene sulfonic acid. High performance water reducing agents such as condensed salts and sulfonated melamine condensed salts, polyoxyalkylene compounds, shrinkage reducing agents such as alkylene oxide adducts of lower alcohols, waterproofing agents and dispersants such as fatty acid metal salts such as aluminum stearate, etc. Compound. Especially in re-emulsified powder resin, the workability is significantly reduced in the usage amount, so be careful of the mixing amount, and if the workability deteriorates, use low-viscosity methyl cellulose or use the resin considered in workability. It is desirable to do.

The low-shrinkage lightweight mortar may be selected appropriately in consideration of shrinkage amount, adhesion strength, water absorption amount, water permeation amount and the like within the above range according to actual required performance. For example, a more desirable formulation example is shown in Table 1.

[0022]

EXAMPLES Using the lightweight mortars having the compositions of 7 types of examples shown in Table 1 and 4 types of comparative examples, various physical property tests were conducted, and the results of Table 1 were obtained. For the method of each test, see JI
It was performed by the test method specified in S A 1916 (base adjustment coating material for building finish coating material). The workability was evaluated in 10 levels, and 4 was not acceptable, 5 and 6 were acceptable, 7 and 8 were good, 9 and 10 were excellent, and excellent and acceptable were subdivided and displayed in detail. Nos. 10 to 9 have good workability (light weight on the edge) and can construct a certain area in a short time. In Nos. 8 to 7, workability is normal and construction on a fixed area is standard. 6 to 5 are
Workability is a little bad (somewhat heavy Kotebaki), and it takes time to construct a certain area. Nos. 4 to 1 are poor in workability (it is difficult to handle Kotebaki heavily).

[Table 1] As is clear from Table 1 above, in the lightweight mortars of Examples 1 to 7 of the present invention, the kneading specific gravity (unit volume specific gravity) is 1.1 to 1.
It has a range of 9 and exhibits low shrinkage, low water absorption, high adhesive force, can be easily smoothed, has flexibility to follow the movement of hot and cold, dry and wet such as the body after curing, and cracks are less likely to occur. It was confirmed to be a thing. Further, particularly in the lightweight mortars of Examples 2 to 7 in which the kneading specific gravity (unit volume mass) is in the range of 1.53 to 1.8, favorable results were obtained in various property tests, particularly in coating workability. . On the other hand, in the lightweight mortars of Comparative Examples 1 and 2 having a kneading specific gravity (unit volume mass) of less than 1.1, a composition satisfying well-balanced performance and characteristics could not be obtained, bending strength was insufficient, and water absorption Was confirmed, and particularly in Comparative Example 1, the adhesive strength was low and the compressive Young's modulus was large. Further, Comparative Examples 3 and 4 having a kneading specific gravity (unit volume mass) of more than 1.9.
It was confirmed that the light-weight mortar of No. 2 did not appear significantly in terms of numerical values, but it was difficult to apply it, and a physical problem that the compressive Young's modulus was large was also confirmed.

The construction relating to the groundwork adjusting method using the low-shrinkage lightweight mortar was experimentally verified on an actual site.

[Execution example] Using the light weight mortar of Example 2 shown in Table 1, about 50 m ² of the first floor south part of RC 5th floor, the outer wall foundation adjustment average coating thickness of 10 mm was applied for 2 weeks in Tsukuba City, Ibaraki Prefecture. After curing, 2 tiles were tiled. The workability during construction was slightly inferior, and there were no problems in appearance and performance, and there were no problems such as floating or peeling of tiles after 2 years.

Using the light-weight mortar of Example 4 shown in Table 1, in the Higashi-Matsuyama City, Saitama Prefecture, the RC structure, 4th floor, 1st floor, south part 1
An outer wall foundation adjustment average coating thickness of 7 mm was applied at 00 m ² , and after curing for 2 weeks, a 2-chome tile was applied. The workability at the time of construction is good, and there is no defect such as floating or peeling of tiles after 1 year and 6 months.

Using the lightweight mortar of Example 7 shown in Table 1, about 50 parts of the RC construction 5th floor 1st floor west part in Matsudo City, Chiba Prefecture
m ^2, performs the outer wall base adjusted mean coating thickness 4mm, two weeks after curing, was carried out for 2 ChoKake tiled construction. The workability at the time of construction is good, and there is no defect such as tile floating or peeling after one year.

Although the present invention has been described based on the embodiments, the present invention is not limited to the above-mentioned embodiments, and may be carried out in any manner as long as the configuration described in the claims is not changed. You can

[0028]

The low-shrinkage lightweight mortar of the present invention and the ground preparation method using the same apply the cement mortar to a highly rigid flat ground such as cast-in-place concrete, precast concrete members, concrete blocks and bricks. It is used at the same time and shows a high followability to the dry / wet / warm-cooled movement of the highly rigid body, and at the time of construction, it can be easily smoothed in about 2 times to the undercoating post-coating thickness of 3 to 25 mm, and after curing It has a high adhesive strength and also has a high adhesive strength with the splicing mortar, and it is possible to prevent cracking due to curing and drying and infiltration of external rainwater with low shrinkage and low water absorption.

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) C04B 14:38 C04B 16:06 Z 16:06 24:26 Z 24:26) (72) Inventor Hidenori Kojima 13 Torihama-cho, Kanazawa-ku, Yokohama-shi, Kanagawa Fujikawa Construction Materials Co., Ltd. (72) Inventor Kazuya Wada 13 Torihama-cho, Kanazawa-ku, Yokohama-shi, Kanagawa Fujikawa Construction Materials Co., Ltd. (72) Ryoji Nitta 2-5-8 Kita-Aoyama, Minato-ku, Tokyo Intra-company group (72) Inventor Takayuki Masuda 2-5-8 Kita-Aoyama, Minato-ku, Tokyo Intra-company group F-term (reference) 4G012 PA02 PA04 PA07 PA15 PA24

Claims (4)

[Claims] 1. The composition has a unit volume mass of 1.1 to 1.9, exhibits low shrinkage, low water absorption, high adhesive strength, can be easily smoothed, and can be heated / cooled / dried in a skeleton after curing. A low-shrinkage, lightweight mortar characterized by having the flexibility to follow the movements of, and being resistant to cracking. 2. Cement 17-52 wt%, lightweight aggregate 4.0-10 wt%, inorganic admixture 30-72 wt%,
Short fiber 0.05 to 0.2 wt% and organic admixture 6.4 to 1
The low-shrinkage lightweight mortar according to claim 1, characterized in that it contains 1 wt%. 3. A base conditioning method, wherein the composition has a unit volume mass of 1.1 to 1.9, exhibits low shrinkage, low water absorption, high adhesive force, can be easily smoothed, and has a post-curing structure, etc. A base using low shrinkage lightweight mortar characterized by using low shrinkage lightweight mortar that has flexibility to follow the movements of hot, cold, dry and wet, and is resistant to cracking, as a base conditioning agent and / or finishing material Adjustment method. 4. Cement 17-52 wt%, lightweight aggregate 4.0-10 wt%, inorganic admixture 30-72 wt%,
Short fiber 0.05 to 0.2 wt% and organic admixture 6.4 to 1
The low-shrinkage lightweight mortar containing 1 wt% is used, and the undercoat adjusting method using the low-shrinkage lightweight mortar according to claim 3.