KR101394783B1 - Improvenment material of early age strength using industrial by products - Google Patents

Abstract

The present invention relates to an environmentally friendly mortar and concrete composition, which can exhibit high compressive strength even when a small amount of cement is used, and uses industrial by-products as waste, To 40 parts by weight of alumina, and 40 to 60 parts by weight of fine powder of blast furnace slag.

Description

TECHNICAL FIELD The present invention relates to an initial strength improving material using industrial byproducts, and a mortar and a concrete composition using the same,

The present invention relates to an environmentally friendly mortar and concrete composition, which can exhibit high compressive strength even when a small amount of cement is used, and uses industrial byproducts as waste as a main material.

It is recognized as a severe environmental and pollution industry such as forest destruction due to the extraction of limestone which is a raw material of cement product, high energy burning cost, global warming due to carbon dioxide (CO ² ) emission and incinerator of environmental waste. Regulations and laws are strengthened.

The use of cement for mortar and concrete has been reported to cause various dermatitis, atopy and headache as a strong alkali.

In this way, it is recognized that solving problems in resource, environment and economical aspects due to excessive use of cement in the construction industry is recognized as a very important task.

In addition, there is a problem in that the sagging or cracking of the product occurs when moving the molding pallet to the forklift after the cement-related manufacturing factory and the concrete second product and the mortar molding at the production site, have.

Meanwhile, coal as a by-product of the thermal power plant is being recycled as cement raw materials or admixture materials, but a considerable part of it is simply landfilled and disposed of. Therefore, considering the natural environment preservation and lack of landfill, Is an urgent situation.

In order to solve such problems, the present invention can improve the initial strength after molding of mortar and concrete products, prevent damage and defects of the product, and replace the large specific gravity of cement, thereby improving the environment and preventing pollution An initial strength improving material using industrial byproducts capable of reducing material cost and construction time, and a mortar composition and a concrete composition using the same.

According to an aspect of the present invention,

The present invention provides an initial strength enhancing material using industrial byproducts comprising 20 to 40 parts by weight of Ⅱ type anhydrous gypsum, 20 to 40 parts by weight of alumina and 40 to 60 parts by weight of fine powder of blast furnace slag in 100 parts by weight of combustion sludge.

Particularly, it is preferable that 20 parts by weight of the Ⅱ anhydrous gypsum, 20 parts by weight of alumina and 60 parts by weight of the blast furnace slag powder are mixed in 100 parts by weight of the combustion slaked lime.

Further, the present invention is characterized in that 200 to 400 parts by weight of an initial strength-enhancing material is mixed with 100 parts by weight of cement,

Wherein the initial strength improving material is a mixture of 20 to 40 parts by weight of Ⅱ type anhydrous gypsum, 20 to 40 parts by weight of alumina and 40 to 60 parts by weight of fine powder of blast furnace slag in an amount of 100 parts by weight of the combustion slaked lime. To provide an enhanced mortar composition.

It is preferable that the initial strength-enhancing material is composed of 20 parts by weight of Ⅱ-type anhydrous gypsum, 20 parts by weight of alumina and 60 parts by weight of fine blast furnace slag in 100 parts by weight of the combustion slaked lime.

Particularly, it is preferable that the initial strength improving material is mixed with 300 parts by weight of 100 parts by weight of cement.

In addition, the present invention is characterized in that cement, initial strength improving material, sand, aggregate, water and an admixture are mixed,

200 to 400 parts by weight of the initial strength improving material is mixed with 100 parts by weight of cement, 20 to 40 parts by weight of the Ⅱ type anhydrous gypsum, 20 to 40 parts by weight of alumina and 40 to 60 parts by weight of the blast furnace slag are mixed The present invention provides a concrete composition having improved initial strength using an industrial by-product.

It is preferable that the initial strength-enhancing material is composed of 20 parts by weight of Ⅱ-type anhydrous gypsum, 20 parts by weight of alumina and 60 parts by weight of fine blast furnace slag in 100 parts by weight of the combustion slaked lime.

It is also preferable that the initial strength-improving material is mixed with 300 parts by weight of 100 parts by weight of cement.

The present invention improves the initial strength after molding of mortar and concrete products, thereby preventing damage and defects of the product, replacing a large proportion of cement, thereby improving the environment and preventing contamination. There is an effect that it can be shortened.

Hereinafter, the initial strength improving material using the industrial by-product of the present invention, the mortar composition and the concrete composition using the same will be described in detail as follows.

The initial strength improving material using the industrial byproduct of the present invention is composed of 20 to 40 parts by weight of the Ⅱ type anhydrous gypsum, 20 to 40 parts by weight of alumina and 40 to 60 parts by weight of the blast furnace slag fine powder in 100 parts by weight of the combustion sludge.

The combustion slag is intended to react with blast furnace slag and alumina to improve initial strength and long-term strength.

Type II gypsum is used to develop initial strength, which is dried and then pulverized and powdered. The above-mentioned Type II anhydrous gypsum is used in an amount of 20 to 40 parts by weight based on 100 parts by weight of the combustion slaked lime. When it is used in an amount of less than 20 parts by weight, a large amount of ettringite can not be produced in an initial stage, and thus there is a problem in initial strength development. When mixed in an amount exceeding 40 parts by weight, an expansion crack occurs in a product such as concrete caused by over- And there is a problem that the strength is lowered.

Alumina and blast furnace slag are materials for improving long-term strength. They contain CaO and Al ₂ O _{3 in an amount} of 20% or more. These materials react with calcium hydroxide produced at the hydration of the combustion slurry at room temperature to form stable insoluble calcium silicate hydrate Or calcium hydrate of calcium aluminate, etc., and the long term strength is improved by the reaction by such pozzolan.

The alumina and the blast furnace slag are mixed with 20 to 40 parts by weight of alumina and 40 to 60 parts by weight of the blast furnace slag with respect to 100 parts by weight of the combustion sludge so that the slag can effectively react with the combustion slag and the cement to enhance the strength.

Particularly, it is preferable that 20 parts by weight of Ⅱ type anhydrous gypsum, 20 parts by weight of alumina and 60 parts by weight of fine blast furnace slag are mixed in 100 parts by weight of combustion sludge in order to effectively exhibit initial strength.

On the other hand, it is preferable to use the above-mentioned combustion sludge, type II anhydrous gypsum, alumina and blast furnace slag with a powdery degree of 3500 to 5000 cm ² / g.

200 to 400 parts by weight of the initial strength-improving material is mixed with 100 parts by weight of the cement. If the initial strength-enhancing material is used in an amount less than 200 parts by weight, the initial strength is low, the coagulation time is long, and the workability is poor. When 400 parts by weight of the initial strength-

Particularly, it is preferable that 300 parts by weight of the initial strength-enhancing material is mixed with 100 parts by weight of the cement.

Hereinafter, the initial strength improving material using the industrial by-product of the present invention and the mortar and concrete composition using the same will be described with reference to examples, but the scope of the present invention is not limited to the following examples.

[Initial strength Promoting material  combination]

Alumina and blast furnace slag were used as the main materials of the initial strength improving material, and the ratios of the materials other than the combustion lime were applied as shown in Table 1 below.

Percentage of initial strength enhancing material by material No Combustion flue Type II anhydrous gypsum Alumina Blast furnace slag
One

100
20
20
60
2

100
40
20
40
3

100
20
40
40

Then, the specific gravity and the degree of the powder were measured for the initial strength enhancing materials of Nos. 1 to 3 above, and the results are shown in Table 2 below.

Specific Gravity and Powder of Initial Strength Enhancer of No.1 to No3 No One 2 3
importance

2.80
2.76
2.74 Powder figure
(cm < ² > / g)

3,800
3,715
3,730

As shown in Table 2, the initial strength improving material of No. 1 to No. 3 of the initial strength improving materials of No. 1 to No. 3 was excellent in specific gravity and powderity, and therefore the mortar and concrete composition were manufactured using the initial strength increasing material of No. 1 .

[Formulation of mortar composition]

Table 1 shows the physical and chemical properties of Portland cement.

importance Powder figure
(cm < ² > / g) Stability congelation Compressive strength First minute (minute) Closing (time) 3 days 7 days 28th 3.18 3,470 0.02 90 2:56 20.6 25.8 35.2 Chemical composition Fe2O3 MgO C3A Thermal loss 3.8 2.2 1.9 2.1

The mortar composition was blended with the ordinary Portland cement having the physical and chemical properties as shown in Table 3 and the initial strength enhancer of No. 1 as shown in Table 4 below.

No One 2 3 4 5 6 7 8 9 10
cement

5
10
15
20
25
30
35
40
45
50 Initial strength enhancing material

95
90
85
80
75
70
65
60
55
50

[Specific Gravity, Curing Time and pH Test of Mortar Composition]

The specific gravity, the setting time and the pH of the mortar composition of No.1 to No.10, which were blended with the general Portland cement in the ratios shown in Table 4, were measured, and the results are shown in Table 5.

No importance Setting time pH First minute (minute) Termination time (minutes) cement 3.18 90 176 12.6 One 2.76 12 85 9.1 2 2.78 22 94 8.9 3 2.79 31 100 9.3 4 2.76 38 110 9.1 5 2.80 45 126 9.2 6 2.82 56 142 10.2 7 2.80 68 150 11.3 8 2.84 82 165 10.5 9 2.86 86 172 11.6 10 2.87 88 174 12.4

The specific gravity of the mortar compositions No. 1 to No. 10 was lower than the specific gravity of 3.18 of one ordinary Portland cement, but was higher than 2.76. And the condensation time was shorter in the combination of the combustion lime and the finishing time, and the condensation time was shortened because of the influence of the lime scale component and the powdery degree.

[Measurement of compressive strength of mortar]

The compressive strengths of the general Portland cement and the mortar compositions No. 1 to No. 10 blended in the ratios shown in Table 4 were measured and the results are shown in Table 6.

No Compressive strength (MPa) 3 days 7 days a year 28 days old cement 19.8 25.6 34.4 One 17.9 26.6 34.6 2 17.5 25.1 33.7 3 18.1 26.9 34.1 4 19.8 27.8 37.4 5 21.7 29.2 39.5 6 21.3 28.9 38.8 7 21.4 28.7 39.2 8 20.9 28.0 38.4 9 21.8 29.0 40.1 10 21.2 28.5 39.4

As shown in Table 6, the compressive strength of the mortar composition was generally lower in the case of No1 to No4 where the initial strength enhancing material was abundant, and it was judged that the strength was decreased due to a large amount of unburnt powders.

No 7 to No 10 in which the initial strength-enhancing material contained less were excellent in strength, but as shown in Table 5, prolonged setting time and workability were not good.

The combination of No 5 and No 6 with the best mixing condition showed excellent results in mortar strength and coagulation time. Especially, No 5 showed the highest strength by age.

[Formulation of concrete composition]

The cement used was one cement of the common portland cement S, which has the physical and chemical properties as shown in Table 3. As the aggregate, natural fine aggregate for concrete was given and white crushed stone was used. The crushed fine aggregate and coarse aggregate were used as Iksan Kangsan granite The physical properties are shown in Table 7.

Aggregate physical properties division importance Absorption Rate (%) Granulation rate Unit volume weight
(kg / m ³ ) origin Coarse aggregate 2.64 1.2 7.3 1,590 Iksan Kangsan

Table 8 shows the physical and chemical properties of the naphthalene-based high performance AE water reducing agent.

Properties of concrete admixture importance pH % Reduction rate Ratio of bleeding amount (%) Air volume (%) 1.35 6.9 2.0 54 4.6

The above cement, aggregate, initial strength improver No. 1 of Table 1 and admixture were compounded in the ratio shown in Table 9 below.

Concrete formulations No Unit volume weight (kg / m ³ ) Gross weight
(kg / m ³ ) cement Initial strength enhancing material sand aggregate water Mixed material OPC 317 0 856 935 180 1.6 2,290 One 16 301 856 935 180 1.6 2,290 2 32 285 856 935 180 1.6 2,290 3 48 269 856 935 180 1.6 2,290 4 64 253 856 935 180 1.6 2,290 5 80 237 856 935 180 1.6 2,290 6 96 221 856 935 180 1.6 2,290 7 112 205 856 935 180 1.6 2,290 8 128 189 856 935 180 1.6 2,290 9 142 173 856 935 180 1.6 2,290 10 158 157 856 935 180 1.6 2,290

[Characteristics of Uncured Concrete]

The slump, air content, salt content and workability of the concrete compositions No. 1 to No. 10 using the general OPC and the initial strength improving material of Table 9 were tested, and the results are shown in Table 10.

No Slump (mm) Air volume (%) Salinity (%) Workability
(Worcavery) OPC 120 4.5 0.002 Good One 130 4.0 0.004 Severe deflection 2 125 4.0 0.004 There is deflection 3 115 3.9 0.004 Sag 4 120 4.3 0.003 Good 5 120 4.6 0.003 Good 6 115 4.6 0.0025 usually 7 110 4.8 0.0025 Viscous 8 115 4.6 0.0020 usually 9 110 4.7 0.0020 Viscosity is strong 10 105 4.8 0.0015 Viscosity is strong

As shown in Table 10, the concrete compositions No. 1 to No. 10 in which the initial strength enhancer was used in comparison with the general OPC had a good overall slump. However, in the case of No 1 to No 3 containing much of the initial strength improving material, deflection was observed. In the case of No 7 to No 10 in which the initial strength improving material was less blended, a phenomenon of viscosity was observed. The condition of No 5 was the best, but the condition of No 5 showed the best slump, air volume, salt content and workability.

[Compressive strength of concrete]

The compressive strengths of concrete (No. 3, No. 7, and No. 28) for concrete No. 1 to No. 10 using the general OPC and initial strength enhancer shown in Table 9 were measured, and the results are shown in Table 11.

Compressive Strength by Age of Concrete No
Compressive strength (MPa) 3 days 7 days a year 28 days old OPC 20.6 25.8 35.2 One 19.9 27.0 36.5 2 19.4 26.8 34.9 3 19.8 26.9 35.5 4 21.9 30.9 38.6 5 23.7 33.1 41.1 6 23.5 32.4 40.7 7 23.4 33.1 39.8 8 23.2 32.2 39.6 9 23.4 32.1 40.2 10 22.7 30.6 38.4

As shown in Table 11, the compressive strength of No. 1 to No. 4 in which a large amount of initial strength-enhancing material was mixed was evaluated to be lower than that of mortar mixture. In the case of No 7 to No 10 in which the initial strength-enhancing material was less contained, the initial strength was low and the condensation time was long, resulting in poor workability.

On the other hand, in case of No 5 and No 6, the initial strength was higher than that of general OPC of 23.5 MPa or more, the condensation time was short, and the workability was evaluated to be good.

[Concrete drying shrinkage]

The changes in drying shrinkage for the concrete of No 1 to No 10 in which the general OPC and the initial strength enhancing material of Table 9 were used were measured and the results are shown in Table 12.

Concrete dry shrinkage change No Dry shrinkage date 7 days 29th 60 days OPC 0.00008 0.00010 0.00015 One 0.00008 0.00010 0.00013 2 0.00009 0.00011 0.00014 3 0.00008 0.00010 0.00013 4 0.00007 0.00009 0.00011 5 0.00005 0.00008 0.00010 6 0.00005 0.00009 0.00011 7 0.00007 0.00011 0.00014 8 0.00009 0.00013 0.00015 9 0.00009 0.00013 0.00016 10 0.00008 0.00012 0.00014

As shown in Table 12, all of the No 1 to No 10 concrete in which the initial strength-enhancing material was used showed less drying shrinkage than the general OPC. In particular, the initial shrinkage of No 5 and No 6 were small. It is considered that the change of the drying shrinkage is the least because the composition of the initial strength strengthening material and filling of the concrete are the best and the volume change is small.

Claims (8)

100 parts by weight of cement is mixed with 300 parts by weight of initial strength improving material,
Wherein the initial strength enhancing material is a mixture of 20 parts by weight of Ⅱ type anhydrous gypsum, 20 parts by weight of alumina and 60 parts by weight of fine blast furnace slag in 100 parts by weight of the combustion slaked lime.
Cement, initial strength promoting material, sand, aggregate, water and admixture,
Wherein the initial strength enhancing material is obtained by mixing 300 parts by weight of cement with 100 parts by weight of cement and 20 parts by weight of Ⅱ type anhydrite, 20 parts by weight of alumina and 60 parts by weight of fine blast furnace slag in 100 parts by weight of combustion sludge. Wherein the initial strength is increased. delete delete delete delete delete delete