KR100415641B1 - Formed material using slag sand - Google Patents

Abstract

The present invention relates to the composition of concrete secondary products such as bricks and blocks; The purpose is to use the blast furnace slag as aggregate, and to remove the fibrous needles on the surface of the blast furnace slag to improve the workability and to make the compact structure to improve the compressive strength of the molded body. In providing a composition of.

In the present invention having such a purpose, molding using a handmade slag yarn in which a unit volume weight is 1.1 Kg / L or more and -2.5 mm particle size cumulative passing content is 100% mixed with cement 1: 4 to 10. The technical subject matter is about material.

Description

FORMED MATERIAL USING SLAG SAND}

The present invention relates to the composition of concrete secondary products, such as bricks and blocks, and more particularly, by using the surface slag produced by the steelworks blast furnace by surface modification and particle size adjustment as the aggregate of the molding material.

In general, cement and aggregates are mixed with water to form moldings with appropriate strength, commonly referred to as concrete secondary products. Examples include bricks, blocks, sidewalk blocks, road boundary stones, drainage pipes, central dividers, manhole covers, and landscape stone. Aggregate which is a raw material of such a molding is mainly used natural sand or stone powder, and natural sand includes mountain sand, river sand, sea sand and the like. However, as the regulations on protection of natural ecosystem and protection of natural environment are intensified in the future, shortage of natural sand is expected to occur, and the countermeasures are required.

On the other hand, various slag generate | occur | produce in a steel mill. For example, blast furnace slag which is a by-product of blast furnace, steelmaking slag, electric furnace slag, dephosphorization and deoiling slag. The slag produced by blast furnace is roughly divided into lumped slag and reclaimed slag according to the production method. Aggregate slag is produced in the form of large lumps because it is manufactured by slow cooling which gradually cools the slag in the molten state separated from the molten iron in the blast furnace in the steelmaking process and then gradually cools it. On the other hand, the reclaimed slag is blasted by injecting high-pressure water into molten slag and quenched to be shipped in a particulate state composed of more than about 98% amorphous. As the lump ash slag is obtained in a large lump state, it is used as road slab by adjusting the particle size to below a certain particle size. The slag slag is used as cement raw material, blast furnace cement raw material and fertilizer raw material.

Table 1 shows an example of the chemistry of blast furnace slag (lumped slag and water slag).

As shown in Table 1, the blast furnace slag contains about 30% of the SiO ₂ component and has a certain viscosity, so when the blast furnace slag is produced by cooling on the blast furnace column, the surface of the particle is directly contacted by high pressure water. Fibrous saliva is formed on the surface, and the particles are not dense and have a rough structure. In the case of using the aggregate slag in such a state, not only the working environment may be poor, but also the contact strength between the aggregate and the cement paste may be weakened.

The present invention is a part of the method for using the blast furnace slag as aggregate, to remove the fibrous needles on the surface of the blast furnace slag to improve the workability and form a compact structure to improve the compressive strength of the molded body To propose a composition of, there is a purpose.

1 is an optical micrograph showing the morphology of the blast furnace slag

Figure 2 is an optical micrograph showing the particle shape of the blast furnace slag particle size adjustment and surface modified slag yarn according to the present invention

The molding material of the present invention for achieving the above object is constituted by including cement and a handmade slag having a unit volume weight of 1.1 Kg / L or more in a range of 1: 4 to 10.

Hereinafter, the present invention will be described in detail.

In the present invention, the term "manufactured slag yarn" is a surface modification and particle size adjustment of the by-product slag produced in the blast furnace, specifically, it is pulverized so that the unit volume weight of the handmade slag is 1.1Kg / L or more. Such reclaimed slag can replace the sand used as aggregate.

Reclaimed slag generated in the blast furnace of the steel making process is amorphous and has latent hydraulic properties, so when used as aggregate, it has a characteristic that can play an important role in strength development. However, as shown in FIG. 1, the hand slag has a fibrous needle formed on the surface of the particle, which causes damage to the human body by vitreous needles, and in particular, the particles are not dense, which impedes application to the molding material.

The present inventors have studied to remove fibrous needles, and when the slag is pulverized, the surface needles are removed by the friction between particles, and the surface is modified, and a fine structure is formed by the particle size adjustment to secure the strength of the molding material. Found to be beneficial.

According to the present invention, the surface modification and particle size adjustment of the hand slag is performed by a grinder, which is a ball mill, a rod mill, a roller mill, an edge runner, a cone crusher. In general, any commercially available grinder can be used. This mill is used for surface modification and particle size adjustment of the hand slag. At this time, it is important that the unit volume weight of the hand slag is 1.1 Kg / L or more.

Unit volume weight (T) means the unit weight of the aggregate, and refers to the weight of the aggregate in a container of 1L as shown below.

T = {W} OVER {V}

Where W is the weight (Kg) of the sample in the container and V is the volume (L) of the container.

According to the present invention, when the unit volume weight of the ground slag is crushed to be 1.1 Kg / L or more, as shown in FIG. 2, the fibrous needles of the ground slag are removed and the particle size is adjusted. At this time, more preferably, the particle size of the handmade slag yarn is such that the cumulative passing content of -2.5 mm is 100%. The reason is that when the unit volume weight is 1.1Kg / L or more and the particle size is controlled as described above, the strength of the molding material is further improved. Substantially the unit volume weight is determined by the particle size at the time of grinding.

According to the present invention, the handmade slag yarn is used as the aggregate of the molding material. In this case, the mixing ratio of the handmade slag yarn and the cement may be adjusted to the blending ratio used in ordinary concrete secondary products. The mixing ratio of aggregate and cement in this field is managed by various companies, and also depends on the characteristics of the concrete secondary products. Usually, the mixing ratio of cement and aggregate is 1: 4 to 10 in bricks and blocks.

In addition, in the molding material of the present invention, at least one or more of sand, stone powder, stainless slag, and lumped slag may be mixed instead of a predetermined amount of the handmade slag, and the reason for the mixing may be confirmed in the following examples. This is because the characteristic of the is further improved. Here, the stainless slag is a slag from the stainless steel manufacturing process is shown in Table 2, for example the chemical composition. In addition, it is preferable to use the aggregate slag less than -10mm.

More preferably, the aggregate of the molding material is (a) handmade slag: 50% by weight or more, (b) sand, stone powder, stainless slag, aggregated slag, or more: 50% by weight or less. This is because the molding material has the highest strength when the handmade slag yarn is 50% by weight or more.

Hereinafter, the present invention will be described in more detail with reference to Examples.

Example 1

Inventive Example (1-5)

The blast furnace slag 3Kg was put into a ball mill and pulverized so that the unit volume weight was 1.1 to 1.5Kg / L, and then the particle size distribution was confirmed. And the unit volume weight of this crushed wood slag company was measured and confirmed as follows. Fill the slag yarn with up to 1/3 of the container and compact it 25 times with the compaction rod, then fill the slag yarn with up to 2/3 of the container and compact it 25 times with the compaction rod, and then add the slag yarn up to 3/3 of the container. After filling, 25 compactions, and weighing were measured on a straight day. As a result of confirming the measured value, it almost coincided with the unit volume weight defined as the criterion of grinding in the grinder.

Thus, the molding state was observed while adjusting the ratio of the hand slag yarn and the cement obtained in this manner to 10: 1 and the water content to 10-15%, and to prepare the specimen for measuring the compressive strength according to KS regulations. After fabricating the specimen, cure it in the primary room under 50 ℃ × 10hr condition in a curing machine with over 98% humidity, and take it out for 7 days outdoor at room temperature, and measure the compressive strength of the specimen by using a compressive strength tester. 3 is shown. In addition, as shown in Figure 2 by measuring the particle shape of the slag yarn according to the unit volume weight of the particle size adjustment and surface-modified handmade slag as described above.

Comparative Example (1-4)

The particle size distribution and unit volume weight of the wood slag (slag without particle size adjustment and surface modification process) shipped from the blast furnace were measured and shown in Table 3 below. In addition, after the molded slag of the shipped slag (cement slag / cement) with cement was 10, 8, 6, 4 in the same manner as in the invention example, the compressive strength was measured and the results are shown in Table 3. It was. In addition, the particle shape of the slag without particle size adjustment and surface modification was measured by an optical microscope and shown in FIG. 1.

Inventive examples (1 to 5) shown in Table 3 were produced by using a slag yarn manufactured through particle size adjustment and surface modification, all of the compressive strength was 80Kg / cm ² or more. On the other hand, in the case of Comparative Example (1), the molding was not even formed due to the weak contact force between the aggregate and the cement paste, and as in the case of Comparative Examples (2 to 4), even if the aggregate / cement ratio was increased by more than two times, It can be seen that the value is significantly lower than the measured compressive strength. Even when the slag without granularity adjustment and surface modification is not formed like this, it shows low compressive strength even if the mold is not formed again. The cement paste is aggregated because the cement face does not sufficiently penetrate between the aggregate and the aggregate due to the existence of a compact structure and surface needles. This is because the connection between the two is not strong.

On the other hand, Inventive Example (2), which satisfies this, was superior in compressive strength than Inventive Example (5), which had a -2.5 mm particle size cumulative passage.

Example 2

Inventive Example (6-8)

100% of the slag yarn with the unit volume weight adjusted by adjusting the particle size and surface modification by grinding machine, etc., and cement ratio of aggregate is 10: 1 when manufacturing cement brick, and 5: when manufacturing hollow concrete block. After each adjustment to 1, an appropriate amount of water was added and mixed in an impller mixer sufficiently. At this time, the weight of the total aggregate was 1000kg. Thereafter, cement blocks and hollow concrete blocks were molded at a pressure of 45 kg / cm ² , and then cured indoors at 50 ° C. × 10 hr in a curing tank with a humidity of over 98%. After 7 days of outdoor curing, compressive strength and water absorption of cement bricks and hollow concrete blocks were measured and the results are shown in Table 4 below.

As shown in Table 4, Inventive Examples (6 to 8) used a slag yarn having a unit volume weight of 1.1 Kg / L or more, and it was found that the compressive strength of the molded body increased as the unit volume weight increased.

Example 3

Inventive Example (9-21)

For the aggregates in which stainless slag, stone powder, sand, and -10mm lumped slag were mixed in a hand slag yarn having a unit volume weight of 1.78Kg / ℓ manufactured by adjusting the particle size and surface modification by a grinder, etc., as shown in Table 4 below. After adjusting the cement ratio to 6.7: 1, an appropriate amount of water was added and mixed in the impller mixer sufficiently. At this time, the weight of the total aggregate was 1000Kg. Thereafter, cement bricks were molded at a pressure of 45 kg / cm ² , and then cured indoors under a condition of 50 ° C. × 10 hrs in a curing tank with a humidity of 98% or higher. After 7 days of outdoor curing, compressive strength and water absorption of cement blocks were measured and the results are shown in Table 5 below.

As shown in Table 5, Inventive Examples (9 to 21) are binary slag aggregates or water slag yarns in which stainless slag, stone powder, sand, and -10 mm lumped slag are mixed up to 90% by the total aggregate weight ratio, respectively. It showed excellent compressive strength even when used as a five-way mixed aggregate in which stainless slag, stone powder, sand and aggregate slag were mixed. Here, the compressive strength value tended to increase as the amount of wood slag increased.

Therefore, when using blast furnace slag to replace natural sand as fine aggregate used in civil engineering, construction, and structures where compressive strength is important, it is necessary to perform particle size adjustment and surface modification. If particle size adjustment and surface modification are not carried out, as shown in FIG. 1, a large amount of vitreous saliva exists on the surface of the slag particles, which has a harmful effect on the human body.

As described above, the present invention not only improves the contact strength between the aggregate and the cement face by adjusting or surface modification of the blast furnace slag to an appropriate granularity, but also facilitates handling of the slag, thus making natural sand as a civil engineering and construction aggregate. It is to replace the effect.

Claims (2)

In the molding material composed of cement and aggregate, The aggregate is a composite slag yarn having a unit volume weight of 1.1 Kg / l or more, the cumulative passing content of -2.5 mm particle size is 100%, and the mixing ratio of the cement and the composite slag yarn is 1: 4 to 1:10. Used molding materials. The molding material according to claim 1, wherein the molding material is mixed with any one species of sand, stone powder, stainless slag, and aggregated slag instead of a predetermined amount of the handmade slag yarn.