KR101217061B1 - Cement Zero Concrete Composition and Cement Zero Concrete ＆ Cement Zero Concrete Manufacturing Method - Google Patents

Abstract

The present invention relates to a cementless concrete composition and a method of manufacturing cementless concrete using fly ash and blast furnace slag as binders, and replace compressive portions of general fine aggregates with oxidized slag and bottom ash, but have higher compressive strength than conventional cemented concrete. The present invention relates to a concrete compounding technology that enables workability and workability to be secured without decreasing.
The present invention is "binder, coarse aggregate, fine aggregate and water is blended in the weight ratio for the target slump and the target compressive strength, but the binder is a fly ash or a mixture of fly ash and blast furnace slag fine powder, and the chemicals of the binder In the cement concrete composition to which the alkali activator is added to activate the reaction, the fine aggregate is 40 to 80wt% of the general fine aggregate and 20 to 60wt% of the oxide slag of electricity to provide.

Description

Cement Zero Concrete Composition and Cement Zero Concrete & Cement Zero Concrete Manufacturing Method}

The present invention relates to a cementless concrete composition and a method of manufacturing cementless concrete using fly ash and blast furnace slag as binders, and replace compressive portions of general fine aggregates with oxidized slag and bottom ash, but have higher compressive strength than conventional cemented concrete. The present invention relates to a concrete compounding technology that enables workability and workability to be secured without decreasing.

Cement broadly means a substance that bonds a substance to a substance, but generally means an inorganic bond hardener for civil engineering and construction. However, the term 'cement' in the present invention is used in a narrow sense to refer to the 'portland cement (OPC), the main component of lime, silica, alumina, etc., the portland cement and fly ash, bottom ash, blast furnace slag, electricity Inorganic bonding hardeners (a wide range of cements), which contain mixed materials such as furnace oxide slag and loess, are known as 'binders' in advance.

Cement is the most important and widely used structural material used in the modernization of the industry. Cement is the basic material for the construction of various SOCs such as roads, bridges, tunnels, ports, houses and buildings. Such cement is produced in the high temperature (about 1,500 ℃) state during the firing process, that is, clinker manufacturing using limestone as the main raw material, in the process of producing 0.7 ~ 1.0 tonnes of carbon dioxide gas per tonne of cement. As a result, although cement has played an important role in the construction industry, it has recently become increasingly recognized as a negative material for the natural and global environment.

In Korea, cement production is about 63 million tons per year, releasing about 57.7 million tons of carbon dioxide, which is the second largest after the steel industry. On the other hand, since the climate change agreement to prevent global warming was adopted in Rio in Brazil in 1992, the issue of global warming was recognized as a common human task. In particular, since the Kyoto Protocol on the Climate Change Convention was adopted in Kyoto, Japan in 1997, the Kyoto Protocol came into force in 2005, and 38 developed countries must comply with their obligations to reduce greenhouse gases. According to the Kyoto Protocol, there is a difficult task to reduce the average 5.2% of emissions in 1990 during the first commitment period (2008-2012). Such strong GHG reduction efforts are no exception to Korea, and since 2013, it is clear that they will be included in the second mandatory countries that need to reduce GHG emissions. As of 2004, Korea emits 462.12 million tons of carbon dioxide, making it the 10th largest carbon dioxide emitter in the world.

In line with this situation, all domestic industries are making a lot of investments in equipment and technology development to reduce CO2 emissions.In the cement industry, the efficiency of facilities is increased, and the use of alternative fuels instead of bituminous coal is produced or fly ash in the production process. It is trying to reduce the amount of carbon dioxide by using mixed cement such as blast furnace slag.

As a result of this, the use of concrete by partially replacing industrial by-products such as fly ash and blast furnace slag with respect to the amount of cement (OPC) is gradually becoming common. Cement cement concrete that alkali-activates fly ash and blast furnace slag without cement (OPC) Research results are also being published.

In the paper `` Structural Performance and Application of Cemented Concrete Using Alkali Activation '' (Korean Journal of Concrete Sciences Vol. 19, No. 2, 2007. 3), a mechanism by which fly ash and blast furnace slag fine powders are activated and cured by alkali activators Several advantages and disadvantages of concrete and cementless concrete are introduced.

In addition, Korean Patent Application Publication No. 2010-0023453 "Method of manufacturing cementless concrete using fly ash and blast furnace slag" has introduced the strength formability and curing method according to the powder ratio and weight ratio of fly ash and blast furnace slag.

Recently, however, there has been no research on the application of oxidized slag and bottom ash as fine aggregate in cement concrete.

The present invention is to provide a cement concrete composition and cement concrete manufacturing method that can further improve the compressive strength and fluidity compared to conventional cement concrete while applying the oxide slag and bottom ash as an aggregate of cement cement. The purpose.

The present invention is "binder, coarse aggregate, fine aggregate and water is blended in the weight ratio for the target slump and the target compressive strength, but the binder is a fly ash or a mixture of fly ash and blast furnace slag fine powder, and the chemicals of the binder In the cement concrete composition to which the alkali activator is added to activate the reaction, the fine aggregate is 40 to 80wt% of the general fine aggregate and 20 to 60wt% of the oxide slag of electricity to provide.

In addition, the present invention is "binder, coarse aggregate, fine aggregate and water is blended in the weight ratio for the target slump and the target compressive strength, the binder is a fly ash or a mixture of fly ash and blast furnace slag fine powder, the binder In the cement concrete composition with an alkali activator added to activate the chemical reaction of the fine aggregate, the fine aggregate is composed of 30 to 79 wt% of the general fine aggregate, 20 to 60 wt% electric furnace oxide slag and 1 to 10 wt% bottom ash Cementless concrete composition "to be provided together.

In addition, the present invention provides the "cement cement composition, characterized in that the binder is composed of fly ash 88 ~ 99wt% and blast furnace slag fine powder 1 ~ 12wt% ''.

In addition, the present invention provides the "cement cement composition, wherein the alkali activator is applied with sodium hydroxide powder, and the weight ratio of the sodium hydroxide powder and water is 1: 1: 1.86-5.00.

In addition, the present invention "(a) fly ash and blast furnace slag fine powder mixture, the general fine aggregate, the fine aggregate aggregated with the electric furnace oxide slag and the bottom ash, coarse aggregate and water, the weight ratio for the target slump and the target compressive strength expression Mixing by mixing; (b) adding sodium hydroxide powder and mixing to prepare a cementless concrete composition; (c) curing the cement concrete composition at 60 ° C. for 1 day, and then curing the air at 20 ° C. until the measurement age; Cemu cement concrete manufacturing method characterized in that it comprises a.

In addition, the present invention "the step (a) is the binder, fine aggregate, coarse aggregate and water into a mixer for 10 to 300 seconds mixing at 20 ~ 60rpm, the step (b) by adding the sodium hydroxide powder Cemu cement concrete manufacturing method characterized by mixing for 60 to 300 seconds at 30 ~ 50rpm.

According to the present invention, by applying the electric furnace oxidized slag and bottom ash as fine aggregate of cement concrete, it reduces carbon dioxide generation, solves the problem of aggregate supply and demand imbalance and depletion of natural resources, and expands the scope of industrial by-products. Can be.

1 and 2 are graphs showing the slump and the compressive strength of cementless concrete in which an oxidized slag was applied as a fine aggregate.
3 and 4 show the results of slump and compressive strength of cementless concrete in which the composition ratio of oxidized slag was fixed to 40wt% in the fine aggregates and then the composition ratio of bottom ash was substituted in the range of 0 to 15wt%. It is a graph.
5 and 6 are graphs showing slump and compressive strength results of cementless concrete according to the use ratio of fly ash (F / A) and blast furnace slag fine powder (BFS) constituting the binder.
7 and 8 are graphs showing slump and compressive strength measurement results according to a mixing ratio of sodium hydroxide powder and water.
9 is a graph showing the compressive strength according to the curing temperature conditions of cementless concrete.

Ⅰ. Cement Concrete Composition

Cementum composition provided by the present invention is a binder, coarse aggregate, fine aggregate and water is formulated in a weight ratio for the target slump and the target compressive strength. Therefore, the mixing ratio of each of the components may vary depending on the target value of the slump and the compressive strength, which is a general matter, so the description thereof will be omitted.

Cementless concrete literally does not use cement (OPC) at all, but instead uses only fly ash as a binder or a mixture of fly ash and blast furnace slag powder. The basic strength expression mechanism of the cementless concrete is to dissolve atoms such as aluminum and silica in fly ash and blast furnace slag with high concentrations of alkali components to impart hardening performance. Therefore, an alkali activator for activating the chemical reaction of the binder should be added to the cement cement, and an alkali hydroxide (ROH) or a silicate in the form of R ₂ O · (n) SiO ₂ may be used as the alkali activator. R is an alkali metal ion such as Na, K, Li, and the like, and sodium hydroxide, sodium silicate, potassium silicate, sodium carbonate, sodium sulfate and the like are generally used alkali activators.

The present invention has the greatest feature in that the oxidized slag is applied as a part of fine aggregate compounded in cement concrete as described above, and furthermore, bottom ash can be applied as part of fine aggregate. When a part of the fine aggregate is replaced by the oxidized slag by electricity, the fine aggregate may be composed of the general fine aggregate 40 ~ 80wt% and the electric oxidation slag 20 ~ 60wt%.

1 and 2 are graphs showing the slump and the compressive strength of the cementless concrete in which the oxidized slag was applied as the fine aggregate with electricity (see conditions in Table 1 below). The slump shown in [FIG. 1] is a result measured immediately after mixing according to KS F 2402, and the compressive strength shown in [FIG. 2] is a cylindrical test specimen having a diameter of 100 × 200 mm to produce a compressive strength for 1 and 28 days. Is the result of measuring.

Composition ratio of oxide slag by electric furnace (wt%) Binder use ratio Use weight ratio of sodium hydroxide powder and water Curing temperature
(℃) F / A BFS Sodium hydroxide powder water 0

97

3


One


2.21



60 20 40 60 80 100

In the case of concrete slump, the slump increased as the composition ratio of oxidized slag increased with electricity, but the slump when 100 wt% of oxidized slag was used as fine aggregate was 225 mm, which is out of the target slump range. 1]).

In the case of compressive strength, the compressive strength was higher than that of conventional cement concrete (electricity slag 0wt%) until the composition ratio of oxidized slag was 60wt%, but the compressive strength was 80wt% and 100wt%. Was found to be somewhat lowered (see FIG. 2).

As a result of reviewing the above slump and compressive strength, when the 20 ~ 60wt% of fine aggregate is composed of oxidized slag of electric furnace, it shows that the relative workability and compressive strength are improved compared with the conventional cement concrete which does not use oxidized slag of electricity at all. In particular, when 40wt% of fine aggregate was composed of oxidized slag with electricity, slump and compressive strength were found to be the best.

Electrically oxidized slag is composed of SiO ₂ , Al ₂ O ₃ , and CaO, so that it reacts with water in high alkali and high temperature environment to produce CSH (calcium silicate hydrate; 3CaO ₂ SiO ₂ 3H), which is a hydration product such as cement. ₂ O) and Ca (OH) ₂ and the like, among these products, CSH contributes to the initial strength expression, Ca (OH) ₂ gives a strong alkaline environment to further activate the polymerization of fly ash, compressive strength It is analyzed to improve.

On the other hand, when the bottom ash is applied as part of the fine aggregate with the oxidation furnace slag, the fine aggregate is composed of 30 to 79 wt% of the general fine aggregate, 20 to 60 wt% electric furnace slag and 1 to 10 wt% bottom ash can do.

3 and 4 show the results of slump and compressive strength of cementless concrete in which the composition ratio of oxidized slag was fixed to 40wt% in the fine aggregates and then the composition ratio of bottom ash was substituted in the range of 0 to 15wt%. (See conditions in Table 2 below).

Furnace Oxidation Slag
Composition ratio (wt%) Bottom ash
Composition ratio
(wt%) Binder use ratio Use weight ratio of sodium hydroxide powder and water Curing temperature
(℃) F / A BFS Sodium hydroxide powder water

40 0

97


3



One





2.21





60



2.5 5.0 7.5 10.0 12.5 15.0

In the case of slump, due to the high absorption rate of bottom ash itself, the composition ratio decreased gradually by 2.5wt%, especially when the composition ratio of bottom ash was 12.5wt and 15.0wt, respectively. It became 175 mm and 170 mm, and it turned out to be out of the range of 180-220 mm which is a target slump range (refer FIG. 3).

As the composition ratio of bottom ash among fine aggregates increased, both the 1st and 28th day compressive strengths were increased compared to the case where no bottom ash was used (see FIG. 4). It is considered that the Si and Al components in the bottom ash composed of similar components promoted the polymerization reaction by combining with the alkali activator. Based on the above results, 1 ~ 10wt of fine aggregate is composed of bottom ash.

5 and 6 are graphs showing the results of slump and compressive strength of cementless concrete according to the use ratio of fly ash (F / A) and blast furnace slag fine powder (BFS) constituting the binder (see [Table below] 3].

Furnace Oxidation Slag
Composition ratio (wt%) Use weight ratio of sodium hydroxide powder and water Curing temperature
(℃) Sodium hydroxide powder water

40

One


2.21



60

Increasing the use rate of fly ash, the workability and workability of cementless concrete are secured, but there is a problem that the expression of compressive strength is relatively low.In contrast, in the case of blast furnace slag fine powder, the expression of compressive strength is increased as the use ratio of On the other hand, it is difficult to secure workability and constructability. However, by properly combining the use ratio of fly ash and blast furnace slag powder, it is possible to secure a hardened body in which workability, workability and compressive strength that meet user requirements are expressed.

According to the graph of FIG. 5, when blast furnace slag fine powder was not used at all and only fly ash was used as a binder, the slump was the largest as 215 mm, and the blast furnace slag fine powder used ratio was 3, 6, 9, 12, 15 wt%. As slump was decreased due to rapid reaction with blast furnace slag fine powder and alkali activator, especially 15% of blast furnace slag fine powder had a slump value of 165 mm, which is below the target slump range.

On the other hand, the compressive strength was increased compared to the case of using only fly ash as a binder as the use ratio of blast furnace slag fine powder, as shown in the graph of FIG.

As a result of examining the slump and the compressive strength, it is judged that the composition of the binder capable of satisfying the required workability and workability is 88 ~ 99wt% of fly ash and 1 ~ 12wt% of blast furnace slag powder.

7 and 8 show slump and compressive strength measurement results according to a mixing ratio of sodium hydroxide powder and water (see conditions of Table 4 below).

Furnace Oxidation Slag
Composition ratio (wt%) Binder use ratio (wt%) Curing temperature
(℃) F / A BFS

40

94

6



60

7 and 8 are results of applying sodium hydroxide powder as an alkali activator for activating fly ash and blast furnace slag fine powder. As the mixing ratio of water to calcium hydroxide powder increases, It was found to increase and met the target performance range in all formulations (see FIG. 7). In the case of compressive strength, it was found that the mixing ratio of water was slightly lowered, but all of them showed good strength at 30 MPa or more.

As a result of reviewing the above results, the weight ratio of water to sodium hydroxide powder was found to be able to secure required workability and workability within the range of 1: 1: 1.86 ~ 5.00.

Ⅱ. Manufacturing method of cement concrete

The present invention is (a) fly ash and blast furnace slag fine powder mixture, the general fine aggregate, finely mixed fine aggregate, coarse aggregate and water ash oxide and bottom ash by mixing the weight ratio for the target slump and the target compressive strength Mixing; (b) adding sodium hydroxide powder and mixing to prepare a cementless concrete composition; (c) curing the cement concrete composition at 60 ° C. for 1 day, and then curing the air at 20 ° C. until the measurement age; It provides a cementless concrete manufacturing method comprising a.

In the step (a), the composition of the binder and the composition of the fine aggregate may be specified in the same manner as the above-mentioned cement concrete composition. Step (b) is a step of mixing by adding sodium hydroxide powder as an alkali activator to the composition mixed by the step (a). In step (a), the binder, fine aggregate, coarse aggregate, and water are added to a mixer and mixed for 10 to 300 seconds at 20 to 60 rpm, and in step (b), the sodium hydroxide powder is added to 30 to 50 to 50 rpm. It is desirable to mix for 300 seconds.

Cementum concrete composition prepared by performing the steps (a) and (b) is cured for 1 day at 60 ℃, it is preferable to air-cured at 20 ℃ until the measuring age.

Figure 9 shows the compressive strength according to the curing temperature conditions of cementless concrete (see conditions in Table 5 below).

Furnace Oxidation Slag
Composition ratio (wt%)
Binder use ratio (wt%) Use weight ratio of sodium hydroxide powder and water Curing temperature
(℃) F / A BFS Sodium hydroxide
powder water
40

100

0

One

2.33
20 40 60

At curing temperature 60 ℃, the compressive strength was 39 ~ 40MPa. At curing temperature 40 ℃, the compressive strength was 22 ~ 24MPa, which was somewhat lower than that at 60 ℃. The curing temperature for securing a compressive strength of 30MPa or more is 9 ~ 10MPa, which is considered to be 60 ° C. In the case of the fly ash polymerization reaction, there is a problem that the reactivity is lowered due to the formation of a glass coating (Glassy), it is understood that the high temperature curing as described above is required in order to solve the problem of the reactivity caused by the glass film formation to promote the reaction.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the invention. Therefore, the claims of the present invention include modifications and variations that fall within the true scope of the invention.

none

Claims (6)

delete The binder, coarse aggregate, fine aggregate and water are formulated in a weight ratio for expressing the target slump and the target compressive strength, and as the binder, a fly ash or a mixture of fly ash and blast furnace slag fine powder is applied, and the chemical reaction of the binder is activated. In cementless concrete compositions with added alkali activator,
The fine aggregate is a cementless concrete composition, characterized in that consisting of the general fine aggregate 30 to 79 wt%, 20 to 60 wt% electric furnace slag and 1 to 10 wt% bottom ash.
In claim 2,
The binder is a cementless concrete composition, characterized in that consisting of fly ash 88 ~ 99wt% and blast furnace slag fine powder 1 ~ 12wt%.
In claim 2,
As the alkali activator is applied sodium hydroxide powder,
Cementum concrete composition, characterized in that the weight ratio of the sodium hydroxide powder and water is 1: 1: 1.86 ~ 5.00.
(a) mixing and mixing the combination of fly ash and blast furnace slag fine powder, general fine aggregate, fine aggregate, coarse aggregate, and water mixed with oxidized slag and bottom ash in an electric furnace in a weight ratio for expressing a target slump and a target compressive strength; ;
(b) adding sodium hydroxide powder and mixing to prepare a cementless concrete composition;
(c) curing the cement concrete composition at 60 ° C. for 1 day, and then curing the air at 20 ° C. until the measurement age; Cemented concrete manufacturing method comprising a.
The method of claim 5,
In step (a), the binder, fine aggregate, coarse aggregate, and water are added to a mixer and mixed for 10 to 300 seconds at 20 to 60 rpm,
Step (b) is the cement concrete manufacturing method, characterized in that for 60 to 300 seconds mixing at 30 ~ 50rpm by adding the sodium hydroxide powder.

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