KR101989503B1 - Precast light weight concrete and manufacture method thereof - Google Patents

Abstract

The present invention relates to precast lightweight concrete and a manufacturing method thereof. According to the present invention, the precast lightweight concrete comprises: 150 to 200 kg/m^2 of unit water; 350 to 450 kg/m^2 of a unit binder; 650 to 750 kg/m^2 of unit coarse aggregate; and 500 to 610 kg/m^2 of unit fine aggregate. The binder is premix cement in which high early strength cement and blast furnace slag fine powder are uniformly mixed. The coarse aggregate is artificial lightweight aggregate including bottom ash, wherein the coarse aggregate is formed by mixing the artificial lightweight aggregate with a particle size of 10 mm or more and 20 mm or less and the artificial lightweight aggregate with a particle size of 5 mm or more and less than 10 mm by the ratio of 7:3 to 9:1. Accordingly, the artificial lightweight aggregate is applied to precast concrete such that excellent durability and strength are provided in comparison with existing precast concrete and the specific gravity is decreased through lightweight, thereby providing an effect of reducing a deadweight of a structure.

Description

[0001] PRECAST LIGHT WEIGHT CONCRETE AND MANUFACTURE METHOD THEREOF [0002]

More particularly, the present invention relates to a pre-cast lightweight concrete having excellent durability and strength compared with conventional precast concrete, but also capable of reducing specific gravity through weight reduction and thus reducing the dead load of a structure. Cast lightweight concrete and a method of manufacturing the same.

Lightweight aggregate is generally used for structural strength (lightweight concrete) and non-structural strength (light weight panel / lightweight aggregate) based on the required physical properties (volume weight, compressive strength, water absorption rate, thermal conductivity, Environmental materials (carrier, filter media, vegetation base material, loess balls of health care products) by the porous type (open cell & closed cell) And so on.

The artificial lightweight aggregate is a new concept that has been economically sintered at a high temperature (1150 to 1200 ° C), which satisfies a wide range of functions required in complex modern industrial fields such as lightweight property, heat insulation property, sound absorption property, heat resistance property, Of pure ceramic material.

In the US and Europe, since 1920, manufacturing technology and technology have been mutually leading, and developed a wide range of applications using artificial lightweight aggregates of various sizes, and have been providing excellent stability to civil engineering and construction fields and artificial lightweight aggregate secondary product development And in Japan, since the 1960s, it has been used as a high strength lightweight concrete and secondary product field to build a stable use base.

On the other hand, the problem of improving the performance of construction materials to realize ultra-high-rise, ultra-large, long-span, special structure (ocean structure, etc.) Existing concrete has problems such as low strength and weight of its unit weight, heavy weight of its structural members, and reduced use area. In Korea, the shortage of aggregate for construction civil engineering is getting worse In order to solve this problem, special concrete such as lightweight concrete and high strength concrete has been developed and used in various ways, but it is still not enough.

Korean Patent No. 0975644

In order to solve the problems of the prior art as described above, the present invention applies artificial lightweight aggregate to concrete for precast concrete, thereby reducing the specific gravity through weight reduction while providing excellent durability and strength compared to existing precast concrete, And to provide a precast lightweight concrete capable of reducing dead load and a method of manufacturing the same.

These and other objects of the present invention can be achieved by the present invention described below.

In order to achieve the above-mentioned object, the present invention provides a method for producing an aggregate of water, a binder, a coarse aggregate and a fine aggregate having a unit water amount of 150 to 200 kg / m 3, a unit binding amount of 350 to 450 kg / m 3, a coarse aggregate amount of 650 to 750 kg / Wherein the binder is a premixed cement in which crude steel cement and blast furnace slag fine powder are uniformly mixed and the coarse aggregate is an artificial lightweight aggregate containing bottom ash and having a particle size of 10 mm or more to 20 mm or less The present invention provides a precast lightweight concrete characterized in that an artificial lightweight aggregate and an artificial lightweight aggregate having a particle size of 5 mm or more and less than 10 mm are mixed in a ratio of 7: 3 to 9: 1.

In addition, the present invention provides a pre-cast lightweight concrete wherein the premixed cement is a mixture of 60 to 90% by weight crude steel cement and 10 to 40% by weight blast furnace slag fine powder.

The artificial lightweight aggregate may contain 50 to 70 wt% of SiO ₂ , 10 to 30 wt% of Al ₂ O ₃ , 1 to 10 wt% of Fe ₂ O ₃ , 1 to 5 wt% of CaO, 0.1 to 5 wt% of MgO, and Na ₂ < / RTI > O in an amount of 0.1 to 5% by weight.

In addition, the present invention is characterized in that the artificial lightweight aggregate has a far-infrared emissivity of 0.85 to 0.95 and far-infrared radiation energy of 3.65 × 10 ² to 3.75 × 10 ² W / m ² .

The pre-cast lightweight concrete of the present invention is characterized in that the 28-day compressive strength is 35 MPa or more and the unit volume weight is 1,750 to 1,860 kg / m 3.

Also, in the lightweight concrete, the water reducing agent may be further mixed with the amount of the unit reducing agent of 1 to 20 kg / m 3.

In the present invention, water, binder, coarse aggregate and fine aggregate have a unit water amount of 150 to 200 kg / m 3, a unit binding amount of 350 to 450 kg / m 3, a unit coarse aggregate amount of 650 to 750 kg / m 3 and a unit fine aggregate amount of 500 to 610 kg / ≪ / RTI > Wherein the binder is a premixed cement in which crude steel cement and blast furnace slag fine powder are uniformly mixed, and the coarse aggregate is an artificial lightweight aggregate including bottom ash, an artificial lightweight aggregate having a particle size of not less than 10 mm and not more than 20 mm Wherein the aggregate and the artificial lightweight aggregate having a particle size of 5 mm or more and less than 10 mm are mixed in a ratio of 7: 3 to 9: 1.

According to the present invention, there is an effect of providing a precast lightweight concrete and a method of manufacturing the same, which are excellent in durability and strength as compared with existing precast concrete, and can reduce specific gravity through weight reduction and thereby reduce dead load of a structure.

FIG. 1 is a photograph showing a comparison of filling performances according to mixing ratios of two types of artificial lightweight aggregates having different particle sizes.
2 is a test report analyzing the components of the artificial lightweight aggregate according to the present invention.
3 is a test report on far-infrared emissivity and far-infrared radiation energy of the artificial lightweight aggregate according to the present invention.

Hereinafter, the precast lightweight concrete of the present invention and its production method will be described in detail.

The present inventors have made efforts to develop lightweight precast concrete with improved durability and excellent strength. As a result, water, binder, coarse aggregate and fine aggregate are mixed in a specific ratio, and the binder is uniformly mixed with crude steel cement and blast furnace slag It has been confirmed that when the artificial lightweight aggregate is used as a premixed cement mixed with two or more kinds of aggregates having different particle sizes in particular, the strength and the weight can be improved, the present invention has been accomplished .

The precast lightweight concrete of the present invention is characterized in that water, binder, coarse aggregate and fine aggregate have a unit water amount of 150 to 200 kg / m3, a unit binding amount of 350 to 450 kg / m3, a unit coarse aggregate amount of 650 to 750 kg / To 610 kg / m < 3 >, the binder is a premixed cement in which crude steel cement and blast furnace slag fine powder are uniformly mixed, and the coarse aggregate is an artificial lightweight aggregate including bottom ash, And an artificial lightweight aggregate having a particle size of 5 mm or more and less than 10 mm are mixed in a ratio of 7: 3 to 9: 1.

Specifically, the pre-cast lightweight concrete is characterized in that water, binder, coarse aggregate and fine aggregate have a unit water amount of 170 to 180 kg / m 3, a unit bonding amount of 370 to 420 kg / m 3, a unit coarse aggregate amount of 700 to 750 kg / And the binder is a premixed cement in which crude steel cement and blast furnace slag fine powder are uniformly mixed. The coarse aggregate is an artificial lightweight aggregate including bottom ash, and has a particle size of 10 mm to 20 mm and an artificial light weight The aggregate and the artificial lightweight aggregate having a particle size of 5 mm or more and less than 10 mm are mixed in a ratio of 7: 3 to 9: 1.

The binder of the present invention is based on the use of mixed cement having higher strength than that of one kind of ordinary Portland cement (OPC), and the premixed cement pre-mixed cement) was applied.

The premixed cement used in the present invention is a mixture of 60 to 90% by weight of crude steel cement and 10 to 40% by weight of blast furnace slag fine powder, preferably 65 to 75% by weight of crude steel cement and 25 to 35% by weight of fine blast furnace slag powder, It is possible to improve the powder and compressive strength as compared with conventional precast concrete using 100 weight% of Portland cement (OPC) of the first kind within the range.

The crude steel cement of the present invention can be used as cement which contains less free lime components in cement and has a powdery degree larger than that of ordinary cement so that early strength can be exhibited.

Specifically, the crude steel cement has a powder degree of 3,300 cm 2 / g or more, preferably 4,500 to 5,000 cm 2 / g, and the durability and strength of the concrete are excellent within this range.

The powder of the blast furnace slag powder may be 4,000 to 6,000 cm2 / g, preferably 4,000 to 4,500 cm2 / g. Within this range, the surface area is widened to promote water and hydration reaction, . That is, when the powderyness is less than 4,000 cm 2 / g, the surface area of the cement is so small that the hydration reaction lowers and the reinforcing effect may be deteriorated due to the limit of stress and strength. When the powderyness exceeds 6,000 cm 2 / g The surface area is widened to promote water and hydration reaction, so that stress and strength are improved, but the ventilation is lowered and the economic effect is weak.

The water-binder ratio (W / B) of the present invention is 35 to 50%, preferably 40 to 50%, more preferably 40 to 50% %, And it is possible to provide precast concrete having high strength and light weight within this range.

On the other hand, in order to reduce the weight of concrete, it is necessary to lighten the aggregate (coarse aggregate and fine aggregate) occupying 70 to 80% of the volume of concrete. Therefore, in Korea, one kind of lightweight concrete which uses coarse aggregate as lightweight aggregate and thick aggregate as lightweight aggregate are used as lightweight aggregate and a part of light aggregate is used as lightweight aggregate. However, since the compressive strength of concrete is greatly influenced by the strength of coarse aggregate, which accounts for about 40% of the total volume, it is necessary to adjust the density of coarse aggregate used in lightweight concrete.

In the precast lightweight concrete of the present invention, the coarse aggregate can be incorporated at an aggregate aggregate amount of 650 to 750 kg / m 3, preferably 700 to 750 kg / m 3, and the weight can be reduced while maintaining excellent strength within this range There is an effect.

The coarse aggregate of the present invention is an artificial lightweight aggregate including bottom ash, which is a mixture of an artificial lightweight aggregate having a particle size of 10 mm or more and 20 mm or less and an artificial lightweight aggregate having a particle size of 5 mm or more and less than 10 mm at a ratio of 7: . As a result, the durability and the compressive strength are excellent and the weight can be reduced.

In the present invention, an artificial lightweight aggregate is applied to a precast concrete to provide a lightweight precast concrete having improved durability and excellent strength.

Specifically, the coarse aggregate is an artificial lightweight aggregate including bottom ash and dredged soil, characterized in that an artificial lightweight aggregate having a particle size of 10 mm or more and 20 mm or less and an artificial lightweight aggregate having a particle size of 5 mm or more and less than 10 mm are mixed at a ratio of 8: .

The bottom ash (hereinafter referred to as BA) is an industrial by-product of thermal power generation, and refers to a fly ash generated after coal combustion, which is a large fly ash produced by falling down from the bottom of a boiler. Specifically, the bottom ash is fired at a high temperature (about 1100 to 1200 ° C) of a sintering furnace to have characteristics such as lightweight characteristics, heat insulation, sound absorption, heat resistance and workability and is 60 to 80 wt% . ≪ / RTI >

The dredged soil is a pumped soil, soil, sand or the like deposited on the bottom of a river, lake, or sea, and can be contained in an amount of 20 to 40% by weight based on 100% by weight of the artificial lightweight aggregate.

The artificial lightweight aggregate having a particle size of not less than 10 mm and not more than 20 mm has an absolutely solid density of 1.0 to 1.5 g / cm ³ , preferably 1.2 to 1.4 g / cm ³ , and an artificial lightweight aggregate having a particle size of 5 mm or more and less than 10 mm, To 1.9 g / cm < ³ >, preferably 1.6 to 1.7 g / cm < ³ >, and in this case, the durability and the compressive strength are excellent,

The required density of the present invention can be measured according to the KS F 2504: 2014 test method.

The artificial lightweight aggregate of the present invention is produced by mixing and sintering bottom ash and dredged soil, and comprises 50 to 70% by weight of SiO ₂ , 10 to 30% by weight of Al ₂ O ₃ , 1 to 10% by weight of Fe ₂ O ₃ , To 5 wt%, MgO 0.1 to 5 wt%, and Na ₂ O 0.1 to 5 wt%.

Specifically, the artificial lightweight aggregate contains 60 to 70% by weight of SiO ₂ , 15 to 20% by weight of Al ₂ O ₃ , 5 to 8% by weight of Fe ₂ O ₃ , 1 to 3% by weight of CaO, 0.1 to 3% by weight of MgO, And 0.1 to 3% by weight of Na ₂ O. Within this range, there is an effect of excellent durability and compressive strength, and light weight.

The artificial lightweight aggregate may further comprise at least one selected from the group consisting of K ₂ O, TiO ₂ , P ₂ O ₅ , B ₂ O ₃ , Cr ₂ O ₃ , V ₂ O ₅ , ZrO ₂ , PbO and MnO .

More specifically, the artificial lightweight aggregate has a total composition of 60 to 70% by weight of SiO ₂ , 15 to 20% by weight of Al ₂ O ₃ , 5 to 8% by weight of Fe ₂ O ₃ , 1 to 3% by weight of CaO, , 0.1 to 3 wt% of Na ₂ O, 0.1 to 3 wt% of K ₂ O, 0.1 to 3 wt% of TiO _2, 0.1 to 3 wt% of P ₂ O _5, 0.1 to 3 wt% of B ₂ O _3, 0.01 to 3 wt% of Cr ₂ O _3, 0.01 to 3 wt% of V ₂ O _5, 0.01 to 3 wt% of ZrO _2, 0.01 to 3 wt% of PbO and 0.01 to 3 wt% of MnO, It has the most excellent effect of lighter weight while having excellent compressive strength.

The artificial lightweight aggregate has a far-infrared emissivity of 0.85 to 0.95 and far-infrared radiation energy of 3.65 × 10 ² to 3.75 × 10 ² W / m ² .

Specifically, the artificial lightweight aggregate has a far-infrared emissivity of 0.90 to 0.92 and a far-infrared radiation energy of 3.70 x 10 ² to 3.71 x 10 ² W / m ² .

The far-infrared emissivity and the far-infrared radiation energy of the present invention were measured using a FT-IR spectrometer according to the KCL-FIR-1005: 2001 test method at a measurement temperature of 40 DEG C and a measurement wavelength of 5 to 20 mu m to be.

The artificial lightweight aggregate has a unit volume weight of 900 kg / m ³ or less, or 880 kg / m ³ or less, and preferably 500 to 880 kg / m ^{3. In} this case, weight reduction of concrete is effective.

In the precast lightweight concrete of the present invention, fine aggregate has a unit fine aggregate amount of 500 to 580 kg / m 3; . ≪ / RTI >

In the present invention, when the entire amount of artificial lightweight aggregate is used, the unit volume of concrete can be greatly reduced, but there is a fear of a decrease in strength. Therefore, in the present invention, fine aggregate, The volume mass reduction can be realized.

The fine aggregate preferably has a fine aggregate ratio (S / a,%) of 20 to 40%, preferably 30 to 35%. And the compressive strength of concrete is considerably lowered when it is substituted by 40% or more.

The fine aggregate may be selected from at least one of natural sand, crushed sand and recycled sand, and preferably crushed sand is suitable for the production of lightweight precast concrete.

Natural sand means natural sand collected from beaches, mountains, riverside, crushed sand means sand made by breaking rock, and recycled sand means sand made from waste concrete.

In the lightweight concrete of the present invention, the water reducing agent may be further mixed with the amount of the unit reducing agent of 1 to 20 kg / m 3.

This is because the water reducing agent is incorporated for improving the workability of the concrete, and the amount of the unit reducing agent may be further mixed to 1 to 20 kg / m 3 or 1 to 10 kg / m 3, preferably 2 to 6 kg / m 3 , And the effect of improving the durability and compressive strength of the concrete within this range is excellent.

As the water reducing agent, for example, a polycarboxylic acid-based high-performance water reducing agent may be used, and the water reducing agent dispersant and the preservative may be mixed at a ratio of 9: 1 to 6: 4, preferably 7: 3.

The precast lightweight concrete of the present invention is characterized by having a compressive strength of 24 Pa or more, or 24 to 30 MPa after 14 hours of steam curing.

The pre-cast lightweight concrete may have a compressive strength of 28 MPa or more at 35 MPa and a unit volume of 1,750 to 1,860 kg / m3.

As described above, the precast lightweight concrete according to the present invention is characterized by being able to realize lighter weight as well as excellent compression strength, compared to conventional concrete for precast.

The method of manufacturing precast lightweight concrete of the present invention is characterized in that water, binder, coarse aggregate and fine aggregate have a unit water amount of 150 to 200 kg / m3, a unit binding amount of 350 to 450 kg / m3, a unit coarse aggregate amount of 650 to 750 kg / And a unit fine aggregate amount of 500 to 610 kg / m3; Wherein the binder is a premixed cement in which crude steel cement and blast furnace slag fine powder are uniformly mixed, and the coarse aggregate is an artificial lightweight aggregate comprising bottom ash, and a lightweight aggregate having a particle size of not less than 10 mm and not more than 20 mm The aggregate and the artificial lightweight aggregate having a particle size of 5 mm or more and less than 10 mm are mixed in a ratio of 7: 3 to 9: 1.

For example, the steam curing may be carried out at 15 to 30 ° C for 2 to 3 hours, then heated to 50 to 70 ° C for 2 to 3 hours, maintained at 50 to 70 ° C for 4 hours, Followed by natural cooling for 4 to 6 hours. In this case, it is possible to manufacture precast lightweight concrete having excellent durability and compressive strength.

In the method of manufacturing precast lightweight concrete of the present invention, the compressive strength within 14 hours after the steam curing is 70% or more of the compressive strength at 28 days of age and the compressive strength at 7 days of age exhibits the strength of 100% .

Specifically, the method for producing precast lightweight concrete according to the present invention is characterized in that, after steam curing, the compressive strength is 24 MPa or more, 24 to 30 MPa within 14 hours, the compressive strength at 7 days is 34 MPa or more, 34 to 40 MPa, And a compressive strength of 39 MPa or more, or 39 to 45 MPa.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the present invention. Such variations and modifications are intended to be within the scope of the appended claims.

[Example]

Example 1

The precast lightweight concrete was formulated according to the following Table 1, and the physical properties thereof are shown in Table 2.

The premixed cement (C) used was premixed cement mixed with 70% by weight crude steel cement and 30% by weight blast furnace slag powder. The coarse aggregate (G) had an artificial lightweight aggregate having a particle size of 10 mm to 20 mm, Lightweight aggregate containing less than 10 mm of artificial lightweight aggregate in an 8: 2 ratio was used. Crushed sand of calcareous acid was used as fine aggregate.

As the curing method after the concrete mixing, 2 hours of transposition at 20 캜; Temperature rise to 60 占 폚 for 2 hours; Held at 60 캜 for 4 hours; And 6 hours of natural cooling for a total of 14 hours.

How to measure

Concrete specimens were prepared in accordance with KS F 2403 "Method of specimen preparation for concrete strength test" and compressive strength was measured by KS F 2405 "Concrete compressive strength test method".

The precast lightweight concrete according to the present invention, division combination
burglar W / B (%) S / a (%) Unit material amount (kg / m3) W C S G AD Example 1 35 42.7 30.3 175 410 523 722 3.1

W / B: water-binding ratio

S / a: Fine aggregate rate

W: Unit quantity

C: Premix cement

S: fine aggregate (crushed sand)

G: coarse aggregate (lightweight aggregate)

AD: water reducing agent

The properties of the pre-cast lightweight concrete according to the present invention division Compounding strength Compressive strength (MPa) Unit volume mass (kg / m3) Example 1 35 14hr 7 days 28th Before curing After curing 26.6 36.3 40.9 1836 1819

As shown in Table 1, according to the KS F 2405 and KS F 2462 of the present invention, when the 28-day compressive strength test and the unit mass test were performed, the compressive strength at 28 days of age exceeded 40 MPa and the unit mass was 1,800 to 1,850 kg / m < 3 >, it has been found that the present invention meets both the targeted weight reduction and high intensity expression.

Comparative Example 1

The general precast concrete was blended according to the following Table 3 by using the ordinary aggregate in place of the artificial lightweight aggregate in Example 1, and the physical properties thereof are shown in Table 4. < tb > < TABLE >

General Precast Concrete Blending condition of Comparative Example 1 (general aggregate) division combination
burglar W / B (%) S / a (%) Unit material amount (kg / m3) W C S G AD Comparative Example 1 35 44.3 46.7 155 350 855 983 6.3

General precast concrete Properties of Comparative Example 1 (general aggregate) division Compounding strength Compressive strength (MPa) Unit volume mass (kg / m3) Comparative Example 1 35 14hr 7 days 28th Before curing After curing 22.3 29.0 41.3 2388 2365

Example 2

In Example 1, the lightweight aggregate was an artificial lightweight aggregate having a particle size of not less than 10 mm and not more than 20 mm and an artificial lightweight aggregate having a particle size of not less than 5 mm and less than 10 mm, Therefore, the precast concrete according to the lightweight aggregate mixture ratio is blended and the physical properties thereof are shown in Table 6 and Table 7. [

Comparative Example 2

In Example 2, the lightweight aggregate was an artificial lightweight aggregate having a particle size of 10 mm or more and 20 mm or less and an artificial lightweight aggregate having a particle size of 5 mm or more and less than 10 mm premixed at 10: Therefore, the precast concrete according to the lightweight aggregate mixture ratio is blended and the physical properties thereof are shown in Table 6 and Table 7. [

Mixed state of precast concrete concrete according to lightweight aggregate mixture ratio division combination
burglar mix
ratio W / B (%) S / a (%) Unit material amount (kg / m3) W C S G
_{(10 to 20 mm)} G
_{(5 to 10 mm)} AD Example 2 35 8: 2 48.2 32.9 180 373 574 552 152 2.8 Comparative Example 2 10: 0 48.2 34.8 180 373 607 670 - 2.8

Properties of Precast Concrete Examples by Lightweight Aggregate Mix Ratio division Mixing ratio Compressive strength (MPa) Unit volume mass (kg / m3) 14hr 7 days 28th Before curing After curing Example 2 8: 2 24.9 34.5 39.5 1,853 1,796 Comparative Example 2 10: 0 23.4 30.6 37.1 1,825 1,768

As shown in Table 6, when the artificial lightweight aggregate having an artificial lightweight aggregate having a particle size of 10 mm or more and 20 mm or less and an artificial lightweight aggregate having a particle size of 5 mm or more and less than 10 mm was used, 23.4 MPa, 7 days compressive strength was 30.6 MPa, and 28 days compressive strength was 37.1 MPa, which means that the strength was lowered in comparison with the case where the mixing ratio was 8: 2 according to the range of the present invention.

In addition, as shown in Table 7 below, it was confirmed that, in the case of the mixing ratio of 8: 2 according to the present invention, the pore filling property by the continuous particle size was superior to the case where the mixing ratio of the artificial lightweight aggregate was 10: 0 .

Comparison of Filling Performance of Precast Concrete Examples by Lightweight Aggregate Mix Ratio Mixing ratio 10: 0 8: 2 Filling Performance Comparison

Claims (7)

Water, binder, coarse aggregate and fine aggregate have a unit water quantity of 150 ~ 200㎏ / ㎥; Unit bonding discretion 350 ~ 450㎏ / ㎥; Unit coarse aggregate amount 650 ~ 750㎏ / ㎥; And a unit fine aggregate amount of 500 to 610 kg / m3; , ≪ / RTI >
The binder is a premixed cement in which crude steel cement and blast furnace slag fine powder are uniformly mixed,
The coarse aggregate is an artificial lightweight aggregate including bottom ash and dredged soil. The artificial lightweight aggregate having a particle size of 10 mm or more and 20 mm or less and the artificial lightweight aggregate having a particle size of 5 mm or more and less than 10 mm are mixed in a ratio of 7: 3 to 9: 1 ,
And a compressive strength of 39 MPa or more at 28 days and a unit volume weight of 1,750 to 1,860 kg / m3.
The method according to claim 1,
Wherein the premixed cement is a mixture of 60 to 90% by weight crude steel cement and 10 to 40% by weight blast furnace slag fine powder.
The method according to claim 1,
The artificial lightweight aggregate is SiO ₂ 50 ~ 70 _{wt%, Al 2 O 3 10 ~} 30 _{weight%, Fe 2 O 3 1 ~} 10 wt%, CaO 1 ~ 5 wt%, MgO 0.1 ~ 5% by weight and Na ₂ O 0.1 to 5% by weight based on the total weight of the pre-cast lightweight concrete.
The method according to claim 1,
Wherein the artificial lightweight aggregate has a far-infrared emissivity of 0.85 to 0.95 and a far-infrared radiation energy of 3.65 × 10 ² to 3.75 × 10 ² W / m ² .
delete The method according to claim 1,
Wherein the water reducing agent is further mixed with the amount of the unit reducing agent of 1 to 20 kg / m 3.
Water, binder, coarse aggregate and fine aggregate are mixed at a unit water amount of 150-200 kg / m 3, a unit binding amount of 350-450 kg / m 3, a coarse aggregate amount of 650-750 kg / m 3 and a unit fine aggregate amount of 500-610 kg / step; And
Steam curing step,
The binder is a premixed cement in which crude steel cement and blast furnace slag fine powder are uniformly mixed,
The coarse aggregate is an artificial lightweight aggregate including bottom ash and dredged soil. The artificial lightweight aggregate having a particle size of 10 mm or more and 20 mm or less and the artificial lightweight aggregate having a particle size of 5 mm or more and less than 10 mm are mixed in a ratio of 7: 3 to 9: 1 ,
And a compressive strength of 39 MPa or more at 28 days and a unit volume weight of 1,750 to 1,860 kg / m 3.

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