KR20160113882A - Dry mortar composition comprising blast furnace slag - Google Patents

Abstract

The present invention relates to a mortar composition and, more specifically, to a dry premix type mortar composition which has excellent workability and physical properties by including slag processed sand as an aggregate, wherein the slag processed sand is obtained by polishing and processing a slag crushing product having the particular specific gravity and the average particle size in a wet state.

Description

[0001] DRY MORTAR COMPOSITION COMPRISING BLAST FURNACE SLAG [0002]

The present invention relates to a mortar composition, and more particularly to a slag mortar composition comprising sand blasted in a wet state and sand blasted as aggregate.

Cement mortar is prepared by adding aggregate to cement and adding water. It hardens and hardens due to hydration of cement. As the aggregate used in combination with the mortar, the natural sand collected from the river, the sea and the mountain is generally used as it is, or the grain size is adjusted by processing.

However, there is a problem that natural sand is costly to collect and transport, resulting in a great increase in the cost of construction. Also, since the collection of natural sand is limited recently from the viewpoint of environmental protection, There is a problem that the construction cost is greatly increased. Therefore, it is required to develop an aggregate capable of replacing natural sand.

Blast furnace slag has been proposed as an aggregate of mortar, which is a subsidiary material generated during steel production, in which the granulated slag is cooled after its cooling. However, since the particle shape of the blast furnace slag does not meet the physical properties of the natural sand, the workability of the mortar is lowered and the natural sand can not be completely replaced. In addition, the mortar containing blast furnace slag has a low curing hardening rate and a low strength development rate in the early age compared to general mortar containing only natural sand, thereby extending the form retention period in the field installation.

Korean Patent No. 10-0356369 (September 30, 2002) Korean Patent No. 10-0272814 (2013.06.03)

It is an aspect of the present invention to provide a dried mortar composition having excellent workability and improved initial strength while containing blast furnace slag as an aggregate.

According to one aspect of the present invention, there is provided a cement composition comprising: cement; A slag having an apparent specific gravity of 2.2 to 3 and an average particle size of 0.1 to 5 mm is subjected to a grinding process in a wet state at a moisture content of 2 to 10 wt% to obtain a slag having a circular ratio of 65% or more, a yield ratio of 65% Processed sand; And a dry mortar composition comprising gypsum, wherein the dry mortar composition is characterized in that the ultrahigh settling time is 15 to 25 minutes and the final settling time is 20 to 30 minutes.

In addition, the slag-treated sand may include at least one selected from blast furnace slag sand and slowly-cooled slag sand.

Further, it may further include an admixture.

Further, it may include 30 to 60 wt% of cement, 30 to 60 wt% of slag-treated sand, and 0.01 to 10 wt% of gypsum.

The weight ratio of the cement to the gypsum may be 1: 0.001 to 0.1.

The dry mortar composition according to one aspect of the present invention can reduce manufacturing cost and manufacturing time compared to the conventional mortar composition by using blast furnace slag as an aggregate instead of natural sand.

The dry mortar composition according to one aspect of the present invention is excellent in workability and can be applied to various fields requiring mortar.

The present invention relates to cement; Slag processed sand having a circular ratio of 65% or more, a win rate of 65% or more, and a surface dry specific gravity of 2 to 3, obtained by grinding a slag crushed material having an apparent specific gravity of 2.2 to 3 and a grain size of 0.1 to 5 mm in a wet state at a moisture content of 2 to 10 wt% And a dry mortar composition comprising gypsum, wherein the dry mortar composition is characterized in that the ultrahardening time is 15 to 25 minutes and the final setting time is 20 to 30 minutes.

In the present invention, the circularity ratio is determined by measuring the area (Amm ² ) and the maximum diameter (Lmm) for 10 particles having the same particle diameter in a particle transmission chart using a computer microscope, .

[Equation 1]

Circular ratio (%) = R / 0.5L x 100

(In the above formula, R means a radius having Amm ² as a center circle, and can be obtained by the following equation (2).)

&Quot; (2) "

R (mm) = √A√π

In the present invention, the blast furnace slag-treated sand is charged into a cylindrical vessel having a diameter of 140 mm and a height of 130 mm in accordance with JIS A1111, and the total volume V of the blast- (%) Of the total amount (%).

In the present invention, the ultrahigh and final settling time means the value obtained by the method of KS L 5108-2007.

Hereinafter, the present invention will be described in more detail.

According to one aspect of the present invention, a dry mortar composition is provided. Here, the dry mortar composition means a mortar composition in the absence of water, and it can be used after being cured by adding an appropriate amount of water at the time of construction.

The dry mortar composition of the present invention comprises cement. The cement is hydrated when water is added, and it hardens and hardens as time passes, thereby joining the aggregates and generating the strength of the mortar. The cement can be any known one, and the cement in the dry mortar composition containing conventional natural sand as an aggregate can be used. For example, Portland cement, blast furnace cement, silica cement, fly ash cement, white cement, or alumina cement may be used, but is not limited thereto. The average particle diameter of the cement particles is not particularly limited, and is preferably 5 to 30 占 퐉, preferably 10 占 퐉.

The dry mortar composition of the present invention comprises slag-treated sand as an aggregate. The slag-processed sand can be obtained by grinding the slag crushed material as a raw material in a wet state to adjust the particle size and shape.

Specifically, a slag crush material having an apparent specific gravity of 2.2 to 3 and an average particle diameter of 0.1 to 5 mm is first prepared as a raw material. When the apparent specific gravity of the slag is less than 2.2, there is a problem that it is difficult to improve the circular ratio and the yield rate of the slag-processed sand produced by the grinding to the level of the natural sand aggregate. Preferably, the apparent specific gravity of the slag disintegration material is 2.7 to 3 in order to further reduce the porosity of the raw material. When the average particle diameter of the slag crushed material falls within the range of 0.1 to 5 mm, it is preferable that the particle diameter of the slag-processed sand obtained after the grinding process is included in the aggregate of the mortar composition. The kind of the slag is not particularly limited, and for example, a blast furnace slag obtained by quenching molten slag discharged from a blast furnace with water, or a blast furnace slag obtained by slowly cooling molten slag may be used, but the present invention is not limited thereto. The slag crushed material is obtained by crushing blast furnace slag or blast furnace slag using a jaw crusher, a gyretor crusher, a dodge crusher, an edge runner, a hammer mill, a disk crusher, a rotary crusher, a ball mill, a conical mill, . The coarse particle ratio (FM) of the slag disintegration is preferably 3.0 to 3.9. When the coarse particle ratio of the slag is within the above range, the total particle diameter of the slag-processed sand to be produced can be adjusted to 2.0 to 2.7.

Next, the prepared slag raw material is abraded and rubbed in a wet state. The abrasive effect is improved when the abrasive is carried out in a wet state rather than in a dry state. The wet state is preferably a condition in which the moisture content of the raw material is 2 to 10 wt%. More preferably, the raw material water content is in the range of 3 to 5 wt%. When the water content is less than 2 wt%, a sufficient polishing effect can not be obtained, and when the moisture content is more than 10 wt%, the surface of the particles is covered with a water film, which makes it difficult to adjust the particle size and shape of the particles. The slag particles obtained by grinding the raw material having the water content in the above range can be dried to produce the slag-processed sand contained in the mortar composition of the present invention. The mechanism for the abrasive machining is not particularly limited and may be carried out using, for example, a cylindrical rotary sliding abrasive machine or the like. If necessary, the slag-treated sand may be dried or classified to be mixed with the dry mortar composition of the present invention.

The slag-treated sand contained as an aggregate in the mortar composition of the present invention satisfies the physical properties of a circular ratio of 65% or more, a win rate of 65% or more and a surface dryness specific gravity of 2 to 3, To have excellent workability. Preferably, the slag-treated sand contained in the aggregate of the present invention satisfies the physical properties of a circular ratio of 90% or more and a surface dryness specific gravity of 2.5 to 2.9.

The dry mortar composition of the present invention comprises gypsum. The gypsum improves the hardening strength of the mortar composition and reduces the change in length after molding.

If necessary, the dry mortar composition of the present invention may further comprise natural sand as an aggregate.

If necessary, the dry mortar composition of the present invention may further comprise an alkali activating agent. When the dry mortar composition of the present invention further comprises an alkali activating agent, the strength and durability of the mortar can be further improved by progressing the pozzolanic reaction, but there may arise a problem that the numerical value of the length after molding increases. As the alkali activating agent, known alkaline stimulants may be used, for example, sodium hydroxide, sodium chloride, calcium chloride, calcium hydroxide and the like, but the present invention is not limited thereto. The content of the alkali activating agent can be adjusted by those skilled in the art in consideration of the strength of the mortar and the change in length after molding.

If necessary, the dry mortar composition of the present invention may further comprise an admixture. As the admixture, a material conventionally added in a conventional mortar composition may be used. For example, at least one selected from the group consisting of a polymer material, an inorganic material, a fiber reinforcing agent, and a pigment may be added and used, but the present invention is not limited thereto. Examples of the polymer material include ethylene-vinyl acetate copolymer, polyvinyl acetate hydrolyzate, methylcellulose, carboxymethylcellulose, and the like, but are not limited thereto. Examples of the inorganic material include, but are not limited to, quicklime, mica, silica sand, serpentine rock, elvanite, kaolin clay, sepiolite, dolomite, limestone and wollastonite. Examples of the fiber reinforcing material include, but are not limited to, pulp and synthetic fibers.

In the dry mortar composition of the present invention, the mixing ratio of the cement and the aggregate is not particularly limited, and the cement and the slag-treated sand may be mixed in the same amount or the ratio of the slag-treated sand may be smaller or larger than the proportion of the cement. For example, the dry mortar composition of the present invention can be prepared by mixing 30 wt% to 60 wt% of cement, 30 wt% to 60 wt% of slag-treated sand, and 0.01 wt% to 10 wt% of gypsum based on 100 wt% of the total dry mortar composition. The dry mortar composition of the present invention can obtain a strength comparable to a mortar using natural sand as an aggregate even when the proportion of the slag-treated sand is larger than the proportion of the cement. Therefore, from the viewpoint of reducing the unit cost of the mortar to be produced, Cement and slag-treated sand in a weight ratio of 1: 1 to 1.2.

In the dry mortar composition of the present invention, the content of gypsum can be adjusted based on the content of the cement component, and it is preferable that the gypsum is contained in the mortar so that the weight ratio of cement to gypsum is 1: 0.001 to 0.1. More preferably, the weight ratio of cement to gypsum is in the range of 1: 0.01 to 0.05.

The dry mortar composition of the present invention can be used as a paste-like mortar by adding water in the same manner as in the conventional dry mortar composition. The content of the water is not particularly limited and can be adjusted in consideration of the flow value and the like. For example, the water may be added to the dry mortar composition in an amount of 25 to 70 wt% based on the total 100 wt% of the paste-like mortar composition.

The dry mortar composition of the present invention can reduce the manufacturing cost and the manufacturing time compared with the conventional mortar composition using natural sand as an aggregate by using blast furnace slag as an aggregate instead of natural sand. In addition, the dry mortar composition of the present invention can be applied to various fields requiring mortar because it has high workability and high replacement ratio of aggregate as compared with conventional slag mortar compositions which can replace only a part of aggregate with slag.

Hereinafter, the present invention will be described in more detail with reference to the following examples and comparative examples in order to facilitate understanding of the present invention. It will be apparent to those skilled in the art that these embodiments are illustrative of the present invention and are not intended to limit the scope of the appended claims and that various changes and modifications may be made to the embodiments within the scope and spirit of the invention , And it is natural that such variations and modifications fall within the scope of the appended claims.

Example

<Confirmation of grinding effect of blast furnace>

(A) having an apparent specific gravity of 2.26, an average particle diameter of 0.01 to 2.5 mm and 20 kg of an electron transfer material slag (B) having an apparent specific gravity of 2.51 and an average particle diameter of 0.01 to 2.5 mm were charged into a reactor having a diameter of 600 mm, a height of 200 mm, The results are shown in Table 1. The results are shown in Table 1. The results are shown in Table 1. [Table 1] &lt; tb &gt;&lt; TABLE &gt;

sample
Apparent specific gravity Performance ratio (%) Circular Ratio (%) Before polishing After polishing Before polishing After polishing Before polishing After polishing Converter slag A 2.26 2.38 47.5 58.0 76.1 85.2 Converter slag B 2.51 2.61 54.2 61.5 78.3 88.9 Natural sand 2.59 64.5 86.4

In Table 1, silica sand was used as natural sand. Referring to Table 1 above, it can be confirmed that the apparent specific gravity, the yield percentage and the circularity ratio of the blast furnace slag are improved by the self-polishing treatment process and are close to the physical properties of the natural sand.

&Lt; Confirmation of effect of abrasion processing performed in a wet state >

The blast furnace slag having an apparent specific gravity of 2.76, an average particle diameter of 0.3 to 5 mm, a yield ratio of 56.6% and a round ratio of 76.1% was crushed by using a double roll crusher in a wet state of a dry state and a moisture content of 3 wt% And the physical properties of the slag-processed sand before polishing and the slag-processed sand after polishing are shown in Table 2 below.

sample Apparent specific gravity Performance ratio (%) Circular Ratio (%) Blast furnace slag cracking 2.76 56.6 79.3 Blast furnace slag processing sand (drying) 2.79 61.9 86.1 Blast furnace slag processing sand (wet) 2.80 65.3 90.5

Referring to Table 2, it can be seen that when the slag-treated sand is polished in the dry state or the wet state, the yield ratio of the sand is more than 60%, but when wetted, the yield rate is 65% .

A slag having a surface dry specific gravity of 2.76 and FM 3.817 was crushed by a roll mill with a roll gap of 1.5 mm in a wet state of 3 wt% in a dry state and a water content of 3 wt%, and the slag was crushed using a cylindrical rotary sliding grinder , FM, surface dry specific gravity, water absorption, volume ratio and performance ratio are shown in Table 3 below. In the following Table 3, the path means the number of passes through the polishing machine.

sample FM Surface dry specific gravity Absorption rate In volume ratio Performance ratio (%) Slag crush 3.817 2.76 2.80 1.52 56.6 Slag
Processed sand
(dry) 1 pass 2.926 2.79 1.63 1.70 61.9 2 passes 2.769 2.79 1.51 1.53 62.9 3 pass 2.533 2.78 1.44 1.77 64.6 Slag
Processed sand
(Wet) 1 pass 2.541 2.80 0.96 1.81 65.3 2 passes 2.242 2.80 0.97 1.87 67.4 3 pass 2.108 2.83 0.88 1.88 67.0

In case of Natural Silica No. 5, which is a type of natural sand, FM2.34, surface dry specific gravity is 2.60, and the yield rate is 57.4%. Referring to Tables 2 and 3, the slag-treated sand obtained by crushing and grinding processing the slag in a wet state can be confirmed to exhibit equivalent or superior physical properties when compared with natural sand. Since the slag-treated sand can be used instead of natural sand in mortar, it is possible to reduce the manufacturing cost of the mortar and reduce the environmental destruction due to the extraction of natural sand.

EXAMPLES Preparation of dried mortar composition

Slowly cooled slowly slag having an apparent specific gravity of 2.71, an average particle diameter of 0.01 to 2.5 mm, a yield ratio of 58.7% and an average circularity ratio of 73.9% was subject to a self-polishing treatment in a wet state using a cylindrical rotary sliding polishing machine to give an apparent specific gravity of 2.80, 2.5 mm, yield ratio 66.5%, and an average circularity ratio of 93.4%. 1100 g of the blast furnace slag-treated sand, 840 g of Portland cement, 40 g of gypsum, and 20 g of an admixture containing ethylene vinyl acetate, cellulose and quicklime were mixed to prepare 2 kg of a dried mortar composition.

Next, 300 to 350 g of water was added to the above composition so as to have a flow rate of about 190 mm to prepare and cure the mortar paste. The physical properties of the prepared mortar are shown in Table 4 below. And measured using a standard specimen.

Test Items Test Methods Measurement result Setting time
Fresh KS L 5108-2007 20 minutes closing 25 minutes Compressive strength


3 hours of age KS F 2476-2007 10.0 N / mm ² 1 day 18.1 N / mm ² 7 days a year 27.5 N / mm ² 28 days old 40.0 N / mm ² After chemical resistance test 34.4 N / mm ² After freeze-thaw test 36.0 N / mm ² Flexural strength 28 days old 15.0 N / mm ² Bond strength 28 days old 2.5 N / mm ² Appearance after chemical resistance test: Crack and peeling Visual inspection clear

Referring to Table 4, it can be confirmed that the mortar prepared by using the dry mortar composition of the present invention including natural sand as a substitute for slag-treated sand has physical properties comparable to those of conventional mortars prepared using natural sand . In addition, the mortar produced using the dry mortar composition of the present invention was found to have good workability. In the case of replacing the slag-treated sand used in the above-described embodiment with the slag crushed material before the grinding process, the compressive strength and the bending strength were measured to be similar to conventional mortar, but the workability was remarkably decreased.

The dry mortar composition of the present invention has excellent strength, chemical resistance, and curing speed, and is excellent in workability, so that it can be applied to various construction sites instead of conventional mortar. In addition, since the dry mortar composition of the present invention can contain natural sand and cement, which are expensive materials, compared to the conventional mortar composition in a low content, the construction cost can be reduced when the mortar is used instead of the conventional mortar composition.

Claims (5)

cement;
A slag process having an apparent specific gravity of 2.2 to 3 and an average particle size of 0.1 to 5 mm in a wet state with a water content of 2 to 10 wt% and a round ratio of 65% or more, a win rate of 65% sand; And
In a dry mortar composition comprising gypsum,
A fast curing time of 15 to 25 minutes, and a final curing time of 20 to 30 minutes.
The dry mortar composition according to claim 1, wherein the slag-treated sand comprises at least one selected from the group consisting of blast furnace slag sand, and slowly-cooled slag sand.
The dry mortar composition of claim 1, further comprising an admixture.
The dry mortar composition according to claim 1, comprising 30 to 60 wt% of cement, 30 to 60 wt% of slag-treated sand, and 0.01 to 10 wt% of gypsum.
The dry mortar composition according to claim 4, wherein the weight ratio of the cement to the gypsum is 1: 0.001 to 0.1.