JPS62207754A - Low shrinkage high strength hydraulic composition - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is directed to cementitious substances, ultrafine powders, ferrous powders, alkali metal chlorides, high performance water reducing agents, and water-based curing shrinkage properties. The present invention relates to a hydraulic composition that exhibits excellent and high compressive strength.

[Prior art]

Cement mortar is widely used as grout for the bases and piers of machine tools, and as a lining material for various molds, but if the volume of cement mortar decreases due to settling or shrinkage, the contact surface This creates gaps between the grout and prevents it from functioning as a grout. For this reason, various studies are being conducted to expand cement mortar. For example, it is already known that attempts are being made to obtain mortar with low shrinkage by combining calcium chloride with ferrous aggregates and expansion agents. By the way (Tokuko Sho 53-1
No. 5087).

However, even in the above-mentioned improved system, if high strength is required, for example, if a compressive strength of 100 ON#f/cIi or more is required, it is not possible to prepare a cement mortar that meets this requirement.

In addition, as a technology to obtain high-strength cement mortar, the main ingredients are cementitious material, ultrafine powder, high-performance water reducing agent, and water.
It is also known that it is possible to achieve a compressive strength higher than that (Japanese Patent Application Publication No. 55-500863).

However, this system suffers from extremely large curing shrinkage, making it impossible to use it as a grout or lining material. As an improvement measure, when calcium chloride and ferrous aggregate are combined with this system, the fluidity is significantly reduced, making it difficult to use it as a grout material or lining material.

For these reasons, there is a strong desire to develop cement mortar that has excellent fluidity, high strength, and low shrinkage.

[Purpose of the invention]

The present inventors conducted various studies in order to solve the above-mentioned problems and find a hydraulic composition with satisfactory characteristics, and as a result, the inventors of the present invention have found that iron powder, alkali metal chloride, and a high-performance water reducing agent are essential. The present inventors have discovered that by combining these, a cement mortar with high strength and low shrinkage can be obtained without impairing fluidity, leading to the completion of the present invention.

[Structure of the invention]

Briefly, this invention relates to a hydraulic composition whose main components are a cementitious material, an ultrafine powder, a ferrous powder, an alkali metal chloride, a high performance water reducer, and water.

Hereinafter, the configuration of the present invention will be explained in detail.

First, the cementitious material used in the present invention will be explained.

Considering that the hydraulic composition of the present invention can be applied to fields that require high strength, such as various grouts, pedestals for machine tools, cement molds, etc., the cementitious material used in the present invention The cured product is IQO
It is desirable to have a compressive strength of ONfff/cm or more. For this purpose, various Portland cements such as Neelite, Ca, 5i05-1 normal, early strength, super early strength, white or sulfate resistant, etc. alone or in combination, as well as blast furnace slag, fly ash, etc. are used. Mixed cement and the like can generally be used. Furthermore, a material mainly composed of blast furnace slag in combination with an alkaline stimulant is also used. In addition, it is also possible to compensate for shrinkage using expanding cement, to develop the required strength in a short time using rapid hardening cement, and to use a gypsum-based high-strength admixture.

The expansion component of the expansion cement is an Etrin guide type, such as Denki Kagaku Kogyo Co., Ltd.'s mounting product name rC3A#2.
0J or calcined CaO is preferable, and among calcined CaO, those calcined at 1,100 to 1,300°C and having an average crystal system of 10μ or less are preferable.

The quick-hardening component of quick-hardening cement is preferably a calcium aluminate-based one, such as alumina cement, a combination of alumina cement and gypsum-based cement, and Denki Kagaku Kogyo Co., Ltd.'s "Denka ESJ" and Onoda Cement ( Co., Ltd.'s product name ``Jet Cement'' is used.

In addition, high-strength admixtures are gypsum-based, and effective examples include Denka Σ-1000, a surface product manufactured by Denki Kagaku Kogyo Co., Ltd., and "Asano Super Mix," a surface product manufactured by Nippon Cement Co., Ltd. be.

In general, in the present invention, some of the various cementitious substances described above can be replaced with inert inorganic materials or metal particles to improve the strength characteristics. In that case, it is necessary for these replacement components to have a particle size approximately equivalent to that of the cementitious material from the viewpoint of fluidity, and preferably a particle size of 1 to 100 μm, more preferably about 5 to 44 μm. It is preferable to have an average particle size of .

Next, the ultrafine powder used in the present invention is a cementitious material (
The average particle diameter is at least one order smaller (average particle diameter of about 10 to 30 μm), and in particular, those with an average particle diameter two orders of magnitude smaller are preferable from the viewpoint of the fluidity properties of the kneaded product and the strength properties of the cured product. This ultrafine powder component improves the fluidity of the mixed system of the above-mentioned cementitious material and the ferrous powder described below, and fills the interparticle voids formed in the mixed system, resulting in an approximate close-packed structure. It is an essential component to improve the strength of hydraulic bodies. As specific examples of ultrafine powder, silica dust (silica fuyum) and siliceous dust, which are by-products when manufacturing silicon, silicon-containing alloys, and zirconia, are particularly suitable, and calcium carbonate, silica gel, opal silica, fly ash, Blast furnace slag, titanium oxide, and finely ground aluminum oxide or cementitious materials can also be used. In particular, the use of ultrafine powder obtained by pulverizing opalescent silica stone, fly ash, blast furnace slag, etc. by using a classifier and a pulverizer in combination is effective in improving shrinkage.

The amount of ultrafine powder used is preferably 40 to 5 parts by weight, more preferably 6 to 90 parts by weight of the cementitious material.
The amount is 35 to 10 parts by weight compared to 5 to 90 parts by weight.

If it is less than 5 parts by weight, the effect of developing high strength is small;
If the amount exceeds 1 part by weight, the fluidity of the mixed wire material will be significantly reduced, making it difficult to mold the material, and developing insufficient strength.

Next, the iron powder and the alkali metal chloride, which are characteristic components in the present invention, will be explained.

In the present invention, the ferrous powder is used for the purpose of imparting expansion force to the hardened body, and examples of the ferrous powder include iron powder and iron balls produced by a reduction method, an atomization method, etc. be. The particle size structure of this iron powder is usually 0.1 to 1.
It is about 0s. In general, the smaller the particle size, the more effective it is at the beginning, but if it is too small, it will be inconvenient to handle in the air and it will be expensive, so a particle size of less than 1 μm is not suitable, while if it is too large, the expansion effect will be less. become uneven,
Since the fluidity of the kneaded material also decreases, the time is up to about 5 seconds. There is no particular restriction on the shape of the particles, but particles with a large specific surface area have a greater effect even in small amounts, so plate-like, columnar, or scale-like particles are preferable to spherical ones.

Further, in the present invention, the alkali metal chloride used together with the ferrous powder is used for the purpose of oxidizing the ferrous powder and imparting expansion power to it.

A specific example of an alkali metal chloride is NaCL.

LiCff1. KCA, CsC! and so on.

Note that the use of alkali metal chlorides is specific;
A similar expansion effect can be obtained by using chlorides such as alkaline earth metals, but when a high performance water reducing agent (described later) is used in combination to achieve a low (water/cement) ratio, it is difficult to obtain fluidity with the latter. The reason for this is not clear, but it is presumed that the high-performance water reducing agent is subjected to a salting-out effect due to a large amount of alkaline earth metal ions, etc., which interferes with the dispersion effect.

The amounts of the ferrous powder and alkali metal chloride used are 20 to 150 parts by weight, preferably 30 to 120 parts by weight, for the total of 100 parts of cementitious material and ultrafine powder, and the latter is 0.3 to 5 parts by weight, preferably 0.
It is 5 to 3 parts by weight.

The high-performance water reducing agent (hereinafter simply referred to as a water reducing agent) used in the present invention refers to a surfactant that does not cause too much delay in setting or excessive air entrainment even when added to cement in large amounts, and has a large dispersing power. Examples of the water reducing agent include those containing as main components salts of naphthalene sulfonic acid formaldehyde condensates, salts of melamine sulfonic penta-acid formaldehyde condensates, high molecular weight phosphoric acid salts, polycarboxylic acid salts, and the like.

Conventionally, the amount of water reducing agent used is 0.3 to 1 part by weight as a solid content per 100 parts by weight of cementitious material, but in the present invention, it is preferable to use a larger amount than that. Preferably, 1 to 5 parts by weight are used.

Water reducing agents reduce the kneaded material to a low water/(cement + ultrafine powder) ratio (
(hereinafter referred to as water/powder ratio), and if it exceeds 10 parts by weight, it will adversely affect the curing reaction.

When such a water reducing agent is used in combination with ultrafine powder, it is possible to obtain a fluid kneaded material that can be molded by a conventional method even at a water/powder ratio of 25% or less.

In the present invention, water is added to the various ingredients described above to form a kneaded product, which is then molded.

Water is necessary for molding, and in order to obtain a high-strength cement hardened product, it is best to use as little as possible, preferably 10 to 30 parts by weight, and preferably 12 to 30 parts by weight of water per 100 parts by weight of the mixture of cementitious material and ultrafine powder. 25 parts by weight is more preferred. If the amount of water is more than 30 parts by weight, it will be difficult to obtain a high-strength cured product, and if it is less than 10 parts by weight, it will be difficult to perform ordinary molding such as pouring. Note that compression molding and the like are not limited to this, and molding is possible even when the amount is less than 10 parts by weight. It is also possible to use molding methods commonly used for cement concrete, such as extrusion molding.

In addition, in the present invention, aggregate can be used in combination with the above-mentioned ingredients. Aggregates that are generally used when mixing concrete in the civil engineering and construction field are good, but harder ones, specifically those with a Mohs hardness of 6 or higher, preferably 7 or higher, or a Knoop indenter hardness of 700, are preferable. j
/mt7r or more, preferably 800Kg/- or more, is preferably used because the strength can be significantly improved. Examples of materials that meet this standard include silica, emery, magnetic steel, magnetic steel, yellow jade, lawsonite, corundum, zenasite, spinel, beryl, gold-cut stone, tourmaline, granite, andalusite, cross stone, Zircon, calcined bauxite, heavy calcined ash, boron carbide, tungsten carbide, ferrosilicon nitride, silicon nitride, fused silica, fused magnesia, silicon carbide, cubic boron nitride, etc., machinable stainless steel, iron powder, etc. , metals such as iron balls, etc.

The aggregate is usually selected in an amount within 5 times the total weight of the cementitious material and the ultrafine powder. However, this does not apply to special molding methods such as pre-packed and post-packed construction methods.

In addition to the above ingredients, it is also possible to add various types of fibers and nets. Fibers include fibers produced by chatter cutting of cast iron, steel fibers, stainless steel fibers, various natural or synthetic mineral fibers such as asbestos and alumina fibers, carbon fibers,
Examples include glass fibers, and natural or synthetic organic fibers such as polypropylene, vinylon, acrylonitrile, cellulose, and the like. Furthermore, it is also possible to use conventionally used steel rods and FRP rods as reinforcement, and these are indispensable especially for large-sized ones. Any method for mixing and kneading the above-mentioned 7 materials may be used as long as they can be mixed and kneaded uniformly, and the order of addition is not particularly limited.

The molded product obtained by molding the mixed material is cured, and various methods can be used for this curing, and any of the following methods may be adopted: room temperature curing, normal pressure steam curing, high temperature and high pressure curing, and high temperature curing. These can be combined if necessary.

〔Example〕

Hereinafter, the present invention will be explained in more detail with reference to Examples.
The invention is not limited to these examples.

(Examples 1 to 3) The ingredients shown in Table 1 were kneaded with a predetermined amount of water using a 21 mortar mixer (low speed 1 minute → high speed 2 minutes → low speed 1 minute).
minutes), the table flow was measured. In addition, the shrinkage rate was measured in accordance with the US Army Corps of Engineers method. (The shrinkage rate is 4X
A 4×1 Bcm specimen was sealed with silicone oil, and a change in lateral length (base length: 10 cm) was determined using a comparator.

). Roughly prepare a 4x4x16cm specimen and heat it to 50°C.
GIL moist curing was performed and the compressive strength was measured. The results are shown in Table 1.

As shown in Examples 1 to 3 in Table 1 below, according to the present invention, cured products with very small curing shrinkage can be obtained. The product of the present invention achieved almost the same curing shrinkage as the conventional low-shrinkage material of Comparative Example 7, and the shrinkage rate was half that of the systems that did not use sodium chloride and iron powder (Comparative Examples 4 and 5). It has become.

On the other hand, in terms of strength, the strength was more than double that of the conventional low shrinkage material (Comparative Example 7) (Examples 1 to 3), demonstrating the effects of the present invention.

〔Effect of the invention〕

ADVANTAGE OF THE INVENTION The present invention provides a hydraulic composition that exhibits excellent fluidity, low shrinkage, and high strength. The low-shrinkage, high-strength hydraulic composition of the present invention is useful in fields that require high strength, such as pedestals for machine tools, grouts for bridge piers, and various molding molds.

Claims (1)

[Claims] A low-shrinkage, high-strength hydraulic composition characterized by containing a cementitious material, an ultrafine powder, a ferrous powder, an alkali metal chloride, a high-performance water reducer, and water as main components.