JPS586709B2 - Slag-based inorganic hardened material - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a slag-based inorganic hardened body used for building materials and the like.

Generally, when a hydraulic slag such as blast furnace slag is used alone to produce a slag-based inorganic hardened body, since the hydration hardening of the blast furnace slag is slow, it takes a long time to manufacture the slag-based inorganic hardened body, making mass production difficult. In addition, the obtained inorganic cured product had high density and low strength.

On the other hand, even when blast furnace slag and gypsum are used in combination to produce a slag-based inorganic hardened body, it still takes a long time to produce the inorganic hardened body because the hydration hardening of the blast furnace slag is slow.

However, in this case, unlike the case of using blast furnace slag alone, a low-density inorganic cured slag yarn was obtained, and the strength was also greater than that produced using slag alone.

However, since the slag-based inorganic hardened body produced in this manner contains gypsum that is soluble in water, there is a problem in that the water resistance is extremely low.

Therefore, the purpose of this invention is to achieve high mass productivity, low density,
It is an object of the present invention to provide a slag-based inorganic cured body having high strength and excellent water resistance.

Next, this invention will be explained in detail.

As a result of repeated research on improving the water resistance of slag-based inorganic hardened bodies that use a combination of hydraulic slag and gypsum such as blast furnace slag, the inventors have developed a composition for hardened bodies that uses a combination of hydraulic slag and gypsum. , and further calcium aluminate monosulfate hydrate (3CaO-AI.

03・CaS04・nH20, n takes a value of approximately 12 (hereinafter abbreviated as MSH) and an alkaline compound accelerates the hydration hardening of hydraulic slag and increases the production speed of the hardened product. It has been found that the water resistance of slag-based inorganic cured products is improved.

That is, by blending MSH and an alkaline compound into a composition for a cured body containing hydraulic slag and gypsum, the gypsum and MSH react in the presence of water to form calcium aluminate trisulfate hydrate (3
CaCIAI203・3CaSO4.

nH20,n has a value of approximately 31 to 32 (hereinafter abbreviated as TSH)) becomes insoluble in water, and furthermore, the alkaline compound promotes hydration hardening of the hydraulic slag.

As a result, a slag-based inorganic cured body with high water resistance can be obtained in a short time.

As shown in the drawing, this slag-based inorganic hardened body has TSH needle-like crystals 2 attached to a large block of slag hydrated hardened body 1, and crystals of this shape mutually form TSH. It is composed of needle-like crystals 2 connected by intertwining.

Therefore, the reinforcing effect due to the entanglement of the rSH needle crystals 2 provides high strength, and the crystals increase the voids, resulting in a low density.

Examples of the hydraulic slag used in this invention include blast furnace slag.

However, the slag is not limited to this, and any hydraulic slag may be used.

MSH is obtained by a conventional method, for example, by blending a CaO component raw material, an Al203 component raw material, and a CaS04 component raw material in a molar ratio of approximately 3:1:1, and performing wet heat synthesis.

As the gypsum, dihydrate gypsum is mainly used, but hemihydrate gypsum or anhydrous gypsum can also be used.

These three components are used in amounts such that the weight ratio of hydraulic slag (S) and TSH (T) in the slag-based inorganic hardened body is S/T = 0.1/1 to 4/1. It is preferable to select one and include it in the composition for a cured product.

If the ratio of hydraulic slag to TSH is below the above-mentioned range, the water resistance provided by the slag will be insufficient, and T
The strength is lower than that of an inorganic cured body consisting only of SH.

In this case, it is thought that the slag acts simply as a filler.

On the other hand, even if the ratio of hydraulic slag to TSH is smaller than 4/1, if it becomes 1.2/1 or more, the strength reinforcing effect of TSH becomes insufficient, and the strength of the slag-based inorganic cured product decreases. At the same time, it becomes difficult to obtain a low-density product.

In addition, the mixing ratio of MSH and gypsum is inappropriate and T
If SH conversion is not completed and any of them remains, the strength of the inorganic cured product will be insufficient.

In particular, if gypsum remains, the strength will drop significantly.

Therefore, it is preferable to allow them to react completely.

Furthermore, if the water-based hardening of the slag is insufficient, the water resistance of the inorganic hardened product will be somewhat poor.

This indicates that slag contributes to water resistance.

Examples of alkaline compounds include NaOH, Ca-(
OH)2, Na2CO3.

Such an alkaline compound is contained in the composition for the cured product.
．． It is preferable to select the amount used so that it is contained in an amount of 1 to 5.0% by weight (hereinafter abbreviated as ``kaku'').

If the content of alkaline compounds is below this range, the effect will be small and the effect of promoting hardening of slag will be small.On the other hand, if the content of alkaline compounds is above this range, the TSH conversion reaction of MSH will be significantly delayed and the effect of promoting water hardening of slag will be reduced. becomes smaller.

The most preferable range is 0.5 to 2.0.

Next, to explain an example of a method for manufacturing a slag-based inorganic hardened body, hydraulic slag, MSH1 stone RE, and an alkaline compound are mixed in a predetermined ratio, water is added and kneaded to form a slurry, and this is molded into a slurry. Pour into the frame.

Then, cultivate it. In this case, the hydration hardening of the hydraulic slag is promoted by the addition of an alkaline compound, and although the curing speed is rather slow at room temperature, it hardens in 2 to 5 hours by heating at 60° to 80°C.

On the other hand, the reaction rate of the TSH conversion reaction is delayed by the addition of an alkaline compound compared to a system without the addition.

As a result, the generated crystals of TSH become fine needle-like crystals,
The degree of intertwining between the crystals becomes stronger, which effectively affects the development of strength.

However, even if the TSH reaction is delayed in this way,
The TSH conversion reaction is completed by heating at 60 to 80°C for 1 to 5 hours.

Therefore, considering the hardening state of hydraulic slag and the production state of TSH, curing should be carried out at a temperature of 60 to 8
It is preferable to carry out the reaction in a humid atmosphere at 0° C. for several hours.

If the temperature is less than 60°C, the slag will not be sufficiently hardened, and 8
When the temperature exceeds 0°C, there is a tendency that the TSH conversion reaction becomes difficult to occur.

In this way, a slag-based inorganic cured body having low density, high strength, and excellent water resistance can be obtained in a short time.

Next, examples will be described together with comparative examples.

Examples 1 to 21, Comparative Examples 1 to 3 The following materials were used as raw materials.

Hydraulic slag: pulverized blast furnace slag (product name: Esment, manufactured by Nippon Steel Chemical Co., Ltd., Blaine value 3500 cr!/g - 4000 crt/g) MSH: Synthesized by slurry method in an autoclave Gypsum: Dihydrate gypsum (1st grade reagent) Alkaline compounds: NaOH, KOH, Ca-(OH)
2. (Additive) NaC03 (both are first grade reagents) The above raw materials were blended as follows.

That is, the hydraulic slag is selected and blended in such a way that its blending amount is in proportion to the total blended solid content as shown in Table 1 below, and the alkaline compound is blended in such a way that its blending amount is based on the total blended solid content. The ingredients were blended in proportions shown in Table 1 below.

Then, the theoretical ratio of MSH and gypsum for TSH synthesis (M
It was selected and blended so that SH)/(gypsum)=0.6470.36.

Next, water is added to this mixture at the water mixing ratio shown in Table 1 (amount of water to blended solids = water weight/total solids weight), stirred and mixed to create a slurry, and this is molded into a mold. It was poured into a frame and cured in a humid air at the temperature shown in the table for the time shown in the table.

Next, it was removed from the mold and dried at 40°C to obtain a slag-based inorganic cured product.

Comparative example 4 Use of MSH was discontinued.

Other than that, a slag-based inorganic cured body was obtained in the same manner as in Examples 1 to 21.

Table 1 shows the conditions of the slurry in the above Examples and Comparative Examples and the results of the performance tests of the obtained slag-based inorganic cured bodies.

As is clear from Table 1, it can be seen that the inorganic cured slags of Examples have a small rate of decrease in water absorption, a low density, and high strength in a short period of time due to the addition of MSH and an alkaline compound.

As the amount of slag increases, its strength improves.

However, if the amount of alkaline compound added is too large or the TSH conversion is incomplete due to insufficient curing, the strength of the cured product is insufficient.

Reference Examples 1 and 2 Using the raw materials of Examples 1 to 21, these raw materials were blended as shown in Table 2 in the same manner as in Examples 1 to 21, and pulp was added to 5 parts of the total solid content of the blend. A slurry was prepared in the same manner as in Examples 1 to 21.

Next, this was made into paper to obtain a slag-based inorganic hardened body.

The results of the performance test of the slag-based inorganic cured product thus obtained are shown in Table 2.

[Brief explanation of drawings]

The drawings are explanatory views for explaining the hardened structure of the slag-based inorganic hardened body of the present invention. 1...Slag hydrated hardened body, 2...TS
Needle crystals of H.

Claims (1)

[Scope of Claims] 1. A slag-based inorganic cured product obtained by curing a composition for a cured product whose main components are hydraulic slag, calcium aluminate monosulfate hydrate, gypsum, and an alkaline compound. 2 The alkaline compound is NaOH, KOH, Ca
Claim 1 is at least one alkaline compound selected from the group consisting of (OH)2, NaCOs.
The slag-based inorganic hardened body described in .