JPS6236059A - High strength cement 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 [Field of Industrial Application] The present invention relates to a high strength cement composition using pulverized blast furnace slag powder.

[Prior Art] Blast furnace slag powder is produced by pulverizing slag by-produced from a blast furnace in a steelworks and making it glassy by rapid cooling such as water cooling or air cooling. It's just in case. Such pulverized blast furnace slag powder has latent hydraulic properties, and at least one or two or more basic stimulants such as calcium hydroxide, cement, calcium sulfoaluminate minerals, various alkali salts, and gypsum are added. It is known that this property quickly develops hydraulic properties and hardens strongly, and the use of high sulfate slag cement, improved blast furnace cement, etc. that takes advantage of these properties has been investigated.

[Problem that the invention seeks to solve]

The combination of the above-mentioned blast furnace cement powder and an alkaline stimulant has low heat generation and is highly effective in preventing cracking due to heat, has low shrinkage during hardening and drying, and has excellent chemical resistance. It has many advantages such as: However, the development of strength is slow, and there are drawbacks such as the need for a longer material life to achieve a certain level of strength compared to ordinary cement compositions, and the difficulty of obtaining high strength. In order to utilize these compositions in a wide range of fields in the future, it is strongly desired to improve the above-mentioned drawbacks.

Based on the above, the inventors have conducted various studies, and as a result,
By combining pulverized blast furnace slag powder, an alkaline stimulant, ultrafine powder and a high-performance water reducing agent on and off the water, and achieving a low water-to-cement ratio, the above drawbacks can be solved and a high-strength cement composition with excellent strength development can be obtained. The present invention was completed based on the knowledge that the present invention can be achieved.

[Means for solving problems]

The present invention is a high-strength cement composition containing pulverized blast furnace slag, an alkaline stimulant, ultrafine powder, a high-performance water reducer, and water as main components.

The present invention will be explained in detail below.

The blast furnace slag powder used in the present invention is made by making slag by-produced from a blast furnace in a steelworks into a glassy substance by rapid cooling such as water cooling or air cooling, and then pulverizing it. However, in order to increase the activity, cement powder with a fineness of 5,500 cm"/f (Blane value) is often used.
cm''/cm are also used. These do not have hydraulic properties by themselves, but they harden strongly when combined with an alkaline stimulant.

This property is called latent hydraulic property. Note that some products are manufactured by adding a small amount of gypsum in advance and pulverizing it.

The alkaline irritants used in the present invention are conventionally known and include various cements, calcium hydroxide, calcium oxide, calcium sulfoaluminate minerals, various inorganic and organic alkali salts, and gypsum (in various forms). At least one type or a combination of two or more types is required. The amount added varies greatly depending on the type of stimulant and the required performance, but it is preferably 50 parts by weight or less, preferably less than 30 parts by weight, based on internal cutting of 100 parts by weight of blast furnace slag.

The ultrafine powder used in the present invention means one having an average particle size at least one order smaller than the commonly used blast furnace slag powder (about 10 to 30 μm on average), and the average particle size is at least two orders of magnitude smaller. A fine powder is preferable from the viewpoint of fluidity of the kneaded product.Furthermore, it is also possible to use a finely ground alkali stimulant as part or all of the ultrafine powder.

As the ultrafine powder, specifically, silica dust and siliceous dust, which are by-products during the production of silicon, silicon alloy, and zirconia, are particularly suitable, and calcium carbonate, silica gel, titanium oxide, aluminum oxide, etc. Fine powder can also be used. Further, it is also possible to use an alkali stimulant such as opalescent silica stone, fly ash, slag or cement that has been pulverized using a classified product. These may be used alone or in combination with 2a1 or more.

In addition to the amount of ultrafine powder used, at least 4 particles that are one order of magnitude thick,
That is, 40 to 95 parts by weight of pulverized blast furnace slag powder
~ 5 Jukeibu-type dishes.

If it is less than 5 parts by weight, the effect of developing high strength will be small and the improvement in fluidity will not be sufficient, and if it exceeds 40 parts by weight, the fluidity of the mixed wire material will be significantly reduced.

The high-performance water reducing agent in the present invention is a surfactant with a large dispersion ability that does not cause significant delay in setting or excessive air entrainment even when added to cement in large quantities, such as formaldehyde condensate of naphthalene sulfonate, melamine, etc. Examples include formaldehyde condensates of sulfonates, high molecular weight trigenine sulfonates, etc. as main components.

Conventionally, the amount of high-performance water reducing agent used is 3 to 1 weight percent of CL as a solid content, but in the present invention, it is preferable to add a larger amount than that, and it is 1 to 5 weight percent. Part is more preferable.

The effect of high-performance water reducing agents on blast furnace slag powder is low, but this is because the ρ-potential of blast furnace slag powder in water is H.
This is because. The effectiveness of the superplasticizer is improved by the addition of Ca''+ ions; for example, when calcium hydroxide is added, the fluidity is improved by the addition of α5 weight, which is more preferable than the addition of 12-2 weight factor. Ru.

In such an amount of the high-performance water reducing agent used, by combining ultrafine powder, it is possible to obtain a fluid mixed material that can be molded by a conventional method even if the water-to-solid ratio is 25 or less.

The water used in the present invention is necessary for molding,
In order to obtain a high-strength hardened product, it is best to use as little as possible, and 12.5 to 30 parts by weight of solids (total of blast furnace slag, alkali stimulant, and ultrafine powder) of 100 parts by weight of dish water is preferred. , more preferably 15 to 28 parts by weight.If the amount of water is more than 30 parts by weight, it is difficult to obtain a high-strength cured product;
When the amount is less than 12.5 parts by weight, it becomes difficult to perform molding such as ordinary casting. Note that compression molding and the like are not limited to this, and molding is possible even when the amount is less than 12.5 parts by weight. Furthermore, it is also possible to use a molding method normally used for cement concrete, such as extrusion molding.

In addition to the above formulations, it is common to use a combination of various aggregates. As the aggregate, materials generally used in the field of civil engineering and construction may be used, such as river sand, mountain sand, sea sand, crushed sand, slag sand, crushed stone, river gravel, crushed slag stone, light aggregate, etc. In addition, if particularly high strength is required, the Mohs hardness is 6 or higher, or the Knoop indenter hardness is 70.
It is better to use 0 kg7wa" or more, examples of which include silica, emery, pyrite, magnetite, yellow jade, lawsonite, corundum, zenasite, spinel,
Beryl, full curb stone, tourmaline, Hanaoka rock, beryl, cross stone, zircon, calcined bauxite, boron carbide, tungsten carbide, ferrosilicon nitride, silicon nitride, fused silica, fused magnesia, silicon carbide, cubic nitride These include boron, crushed ceramics, iron powder, iron balls, and scrap iron.

In addition, it is also possible to combine reinforcing materials such as fibers and nets. Examples of fibers include steel fibers, stainless steel fibers, various natural and synthetic mineral fibers such as asbestos and alumina fibers, carbon fibers, glass fibers, and natural or synthetic organic fibers such as polypropylene, vinylon, acrylonitrile, cellulose, and Kevlar. . Also, as reinforcement materials, are there conventionally used steel rods or 1'RP rods? It is also possible to use

It is also possible to mix substances with other functions, such as solid lubricants and substances imparting thermal and electrical conductivity.

Any method may be used for mixing and kneading the above-mentioned materials as long as they can be mixed and kneaded uniformly, and the order of addition is not limited.

Various curing methods can be applied to cure the molded product, and any of the following methods may be used: room temperature curing, normal pressure steam, high temperature and high pressure, and high temperature curing, and if necessary, it is also possible to carry out a combination of these methods. .

〔Example〕

The present invention will be explained in more detail below with reference to Examples.

Example 1 After kneading and defoaming using a vacuum omnimixer (manufactured by Chiyoda Giken) using the formulation shown in Table 1, 4×4×1600 specimens were prepared, and the compressive strength after curing was measured. The results are shown in Table-2.

For curing, after 80 SRHIEL at 20°C, curing in water at 20°C for 7 days and 28 days, curing in humid air at 50°C for 7 days, and curing in an autoclave at 180°C for 3 hours.

Materials used> Alkaline stimulant: White Portland cement (manufactured by Chichibu) Dihydrate gypsum (special grade reagent) [Σ1000 J (J&C) anhydrite-based admixture ultra-fine powder Nijirica hium (manufactured by Nippon Heavy Industries, Ltd.) High-performance water reducing agent:
β-Naphthalene sulfone i1 [Formalin condensate system [Cellflow 110PJ (specific industrial charge) Silica sand = No. 3.4.5 (mixed in equal amounts) Water: Tap water Blast furnace slag powder Nibrene value 4200 ctw”/t
Table of pulverized blast furnace slag -2 Compressive strength (Yuf 7cm) Example 2 Using the formulation of N002.4 in Example 1, curing shrinkage and drying shrinkage strain were measured, and the dimensional stability was calculated from the sum of both. The curing shrinkage was conducted in accordance with the U.S. Corps of Engineers method, and the drying shrinkage was measured at 20°C, 50% R after 7 days of curing in water.
Measurements were made using the contact gauge method. Also,
As a comparative example, the same evaluation was conducted for a formulation example (Nn1) using only cement instead of blast furnace slag, cement, and gypsum. The formulation composition and evaluation results are shown in Tables 3 and 4.

Table 3 Table 4 [Effects of the Invention] As described above, according to the present invention, it is possible to obtain a high strength cement composition with little drying shrinkage. In addition, by using blast furnace slag as the main component, it is possible to provide a cement composition for concrete that has excellent chemical resistance and high strength, and therefore has even better fastness.

Such a cement composition can be used not only in the field of civil engineering and construction, but also in industrial equipment such as molds, grindstones, and mechanical parts.

Claims (1)

[Claims] 1. A high-strength cement composition containing pulverized blast furnace slag powder, ultrafine powder, an alkali stimulant, a high-performance water reducer, and water as main components.