WO2009005205A1

WO2009005205A1 - Alkali-activated binder with no cement, method for fabricating mortar using it, and method for fabricating alkali-activated reinforcement mortar with no cement

Info

Publication number: WO2009005205A1
Application number: PCT/KR2008/001217
Authority: WO
Inventors: Keun Hyeok Yang; Jin Kyu Song; Kang Seok Lee
Original assignee: Industry Foundation Of Chonnam National University
Priority date: 2007-06-29
Filing date: 2008-03-03
Publication date: 2009-01-08
Also published as: EP2164816A1; JP2010532307A; JP2012232901A; EP2164816A4; JP5733531B2; CN101687704A; EP2164816B1

Abstract

The present invention relates to a cement-free alkali activated binder in which alkaline inorganic materials are appropriately added to an industrial waste such as blast furnace slag, fly ash, meta kaolin and the like, a method for producing mortar using the same and a method for producing cement-free alkali activated reinforcement mortar. Specifically, the present invention relates to a cement-free alkali activated binder that is not only environmentally friendly as being capable of dramatically reducing the carbon dioxide emission, which has been remained as a problem for producing Portland cement, but also has an excellent property, a method for producing mortar using the same and a method for producing cement-free alkali activated reinforcement mortar.

Description

[DESCRIPTION]

[Invention Title]

ALKALI-ACTIVATED BINDER WITH NO CEMENT, METHOD FOR FABRICATING MORTAR USING IT, AND METHOD FOR FABRICATING ALKALI -ACTIVATED REINFORCEMENT MORTAR WITH NO CEMENT

[Technical Field]

<i> The present invention relates to a cement-free alkali activated binder in which alkaline inorganic materials are appropriately added to an industrial waste such as blast furnace slag, fly ash, meta kaolin and the like, a method for producing mortar using the same and a method for producing cement-free alkali activated reinforcement mortar. Specifically, the present invention relates to a cement-free alkali activated binder that is not only environmentally friendly as being capable of dramatically reducing the carbon dioxide emission, that has been remained as a problem for producing Portland cement, but also has an excellent property, a method for producing mortar using the same and a method for producing cement-free alkali activated reinforcement mortar.

<2>

[Background Art] <3> Mortar, which is generally used in a construction field, consists of a binder, water and an aggregate, and the binder that is generally used therefor is Portland cement. To produce Portland cement, an enormous amount of energy is required and the amount of carbon dioxide that is generated for producing it consists 7% of the greenhouse gas emitted from the entire world.

<4> Portland cement is produced by mixing in an appropriate ratio source materials comprising silica, alumina and lime as a main component, adding an appropriate amount of gypsum to a clinker in which a part of said mixture is molten and sintered, and pulverizing the resultant to give a powder. In this regard, to prepare such cement clinker, the source materials should be molten at high temperature of about 1450°C so that an enormous amount of energy is consumed during the process (i.e., about 30 to 35 H of oil/ton). In addition, to produce a ton of cement, it is known that about 700 to 800Kg of carbon dioxide is released during the process.

<5> Under the circumstances, in order to reduce the amount of carbon dioxide emission (i.e., 0.8 ton) that is accompanied with the production of a ton of cement, concrete-manufacturing companies all over the world try hard to cut off the amount of cement they are using.

<6>

[Disclosure] [Technical Problem]

<7> Thus, the present invention, which is devised to solve the problems and disadvantages of prior art as described above, has an object of providing a cement-free alkali activated binder in which alkaline inorganic materials are appropriately added to an industrial waste such as blast furnace slag, fly ash, meta kaolin and the like so that the binder is not only environmentally friendly as being capable of dramatically reducing the carbon dioxide emission, but also has an excellent property.

<8> Further, another object of the present invention is to provide a method for producing cement-free alkali activated mortar by mixing an alkali activated binder, which comprises alkaline inorganic materials including sodium materials and source materials comprising at least any one of blast furnace slag, fly ash, and meta kaolin as an industrial waste, with water and sand, wherein depending on initial flow, compression strength after 28 days, and a development model of the compression strength of the cement-free alkali activated mortar, the mixing ratio among the alkali activated binder, water and sand is determined. As a result, carbon dioxide emission, which has been remained as a problem for producing cement until now, can be dramatically reduced so that the cement-free alkali activated mortar which is not only environmentally friendly but also has an excellent property can be provided. <9> In addition, another object of the present invention is to provide a method for producing cement-free alkali activated reinforcement mortar that is suitable for repair and reinforcement of buildings, as having high initial flowability, little loss in flowability with time, and low compression strength.

<io>

[Technical Solution]

<ii> The cement-free alkali activated binder according to the first example of the present invention, which is to achieve the purpose of the invention as described in the above, comprises alkaline inorganic materials including sodium materials and source materials comprising at least any one of blast furnace slag, fly ash, meta kaolin.

<12> According to a preferred example, the alkaline inorganic materials comprise at least any one of sodium silicate, sodium hydroxide in powder form, liquid type water glass and liquid type sodium hydroxide.

<13> According to a preferred example, the sodium materials are either Na or Na₂O.

<14> According to a preferred example, molar concentration of the liquid type sodium hydroxide is from 8 to 16M. <15> According to a preferred example, weight ratio between the sodium materials and the source materials is from 0.038 to 0.14.

<16> According to a preferred example, weight ratio between the sodium materials and the source materials is from 0.038 to 0.088 when the source materials are blast furnace slag.

<17> According to a preferred example, weight ratio between the sodium materials and the source materials is from 0.114 to 0.14 when the source materials are fly ash.

<18> According to a preferred example, the alkaline inorganic materials further comprise at least any one of potassium silicate, calcium sulfate and belite.

<19> According to a preferred example, alumina or silica that are comprised in the source materials is solidified by melting and synthesis with the sodium materials comprised in the alkaline inorganic materials.

<20> The method for producing cement-free alkali activated mortar according to the second example of the present invention, which is to achieve the purpose of the invention as described in the above, comprises a step of mixing an alkali activated binder, which comprises alkaline inorganic materials including sodium materials and source materials comprising at least any one of blast furnace slag, fly ash and meta kaolin, with water and sand. <2i> According to a preferred example, the alkaline inorganic materials comprise at least any one of sodium silicate, sodium hydroxide in powder form, liquid type water glass and liquid type sodium hydroxide.

<22> According to a preferred example, the sodium materials are either Na or Na₂O.

<23> According to a preferred example, the alkaline inorganic materials further comprise at least any one of potassium silicate, calcium sulfate and belite. <24> According to a preferred example, weight ratio between the alkaline inorganic materials and the source materials is from 0.038 to 0.14. <25> According to a preferred example, weight ratio between the alkaline inorganic materials and the source materials is from 0.038 to 0.088 when the source materials are blast furnace slag. <26> According to a preferred example, weight ratio between the alkaline inorganic materials and the source materials is from 0.114 to 0.14 when the source materials are fly ash. <27> The cement-free alkali activated reinforcement mortar according to the third example of the present invention, which is to achieve the purpose of the invention as described in the above, is produced by mixing a cement-free alkali activated binder, which comprises blast furnace slag, alkaline inorganic materials including sodium materials, calcium hydroxide, melamine water reducing agent and borate salt, with dry sand and water.

<28> According to a preferred example, the borate salt is comprised in a weight ratio of 1% to 5% compared to the blast furnace slag.

<29> According to a preferred example, the calcium hydroxide is comprised in a weight ratio of 5% to 10% compared to the blast furnace slag.

<30> According to a preferred example, the sodium materials are either Na or Na₂O.

<3i> According to a preferred example, the alkaline inorganic materials are sodium silicate and Na₂O, which is the sodium material of the sodium silicate,

is comprised in a weight ratio of 6.4% to 9% compared to the blast furnace slag.

<32> According to a preferred example, the melamine water reducing agent is comprised in a weight ratio of 0.5% to 2% compared to the blast furnace slag. [Advantageous Effects]

<34> As it has been described in detail in the above, the present invention effectively provides a cement-free alkali activated binder, which has high initial strength, an excellent long-term development of strength, low hydration reaction heat, high chemical resistance, high resistance to freeze and melt, high resistance to fire and low non-elastic deformation, etc. As a result, it can be used not only for general buildings, sea structures, and fire-resistant structures but also for a secondary product such as a block, a brick and a roadside boundary structures, etc. Thus, the cement-free alkali activated binder of the present invention can be efficiently used for a broad range of construction field.

<35> Further, according to the present invention, industrial wastes can be transformed into a binder that can replace conventional Portland cement, thus easing an environmental burden. Further, by saving an energy that is required for burning the binder and not releasing carbon dioxide, an environmentally friendly cement-free alkali activated binder is advantageously provided by the present invention.

<36> Further, according to the present invention, an environmentally friendly preparation method is provided without releasing carbon dioxide, contrast to the conventional process for manufacturing Portland cement. In addition, by using industrial wastes such as blast furnace slag, fly ash, meta kaolin and the like as an alkali activated binder, an environmental burden can be eased and cement-free alkali activated mortar, that can save energy for sintering the alkali activated binder, can be advantageously provided.

<37> Further, the present invention effectively provides a cement-free alkali activated mortar, which has high initial strength, an excellent long- term development of strength, low hydration reaction heat, high chemical resistance, high resistance to freeze and melt, high resistance to fire and low non-elastic deformation, etc.

<38> Further, according to the present invention, cement-free alkali activated reinforcement mortar can be effectively produced without using cement .

<39> Further, according to the present invention, environmentally friendly cement-free alkali activated reinforcement mortar can be effectively produced by using an industrial waste such as blast furnace slag.

<40> Still further, the present invention can effectively provide cement- free alkali activated reinforcement mortar that is suitable for repair and reinforcement of buildings, as having high initial flowability, little loss in flowability with time, and low compression strength. [Description of Drawings]

<4i> Figure 1 and Figure 2 are the photos showing the cement-free alkali activated binder according to the first example of the present invention.

<42> Figure 3 and Figure 4 are the photos showing flow of the mortar that is prepared with the cement-free alkali activated binder according to the first example of the present invention.

<43> Figures 5 to 8 are the graphs showing the compression strength after 28 days and the development of compression strength at different aging time of the mortar, that is prepared with the cement-free alkali activated binder according to the first example of the present invention, in accordance with the weight ratio between the sodium materials and the source materials.

<44> Figure 9 and Figure 10 are the graphs showing the shrinkage strain of the mortar that is prepared with the cement-free alkali activated binder according to the first example of the present invention.

<45> Figures 11 to 13 are the photos showing the cement-free alkali activated mortar that is prepared according to the method for the production of cement-free alkali activated mortar according to the second example of the present invention.

<46> Figure 14 and Figure 15 are the graphs showing the flow of the cement- free alkali activated mortar, that is prepared according to the method for the production of cement-free alkali activated mortar according to the second example of the present invention, in accordance with the ratio between water and the alkali activated binder, or the flow of said mortar in accordance with the ratio between sand and the alkali activated binder.

<47> Figure 16 and Figure 17 are the graphs showing the compression strength after 28 days of the cement-free alkali activated mortar, that is prepared according to the method for the production of the cement-free alkali activated mortar according to the second example of the present invention, in accordance with the weight ratio between water and the alkali activated binder, or the compression strength after 28 days of said alkali activated mortar in accordance with the ratio between sand and the alkali activated binder.

<48> Figure 18 is a graph showing initial flow of the cement-free alkali activated reinforcement mortar that is prepared according to the third example of the present invention.

<49> Figure 19 is a graph showing flow loss of the cement-free alkali activated reinforcement mortar that is prepared according to the third example of the present invention.

<50> Figure 20 is a graph showing compression strength of the cement-free alkali activated reinforcement mortar that is prepared according to the third example of the present invention.

<51>

[Best Mode]

<52> [First example]

<53> In the cement-free alkali activated binder of the first example of the present invention, a source material and an alkaline inorganic material are admixed with each other.

<54> In this case, the source material comprises at least any one of blast furnace slag, fly ash, and meta kaolin, and the alkaline inorganic materials comprise at least any one of sodium silicate, sodium hydroxide in powder form, liquid type water glass and liquid type sodium hydroxide.

<55> In this case, for the cement-free alkali activated binder of the present invention, weight ratio between the sodium materials which constitute said alkaline inorganic materials and the source materials is within the range of 0.038 to 0.14. Such weight ratio between the sodium materials and the source materials determines the mechanical properties such as flowability, strength and the shrinkage strain and the like of the cement- free alkali activated binder of the present invention.

<56> In this case, said sodium materials include Na, Na2θ and the like. The weight of the sodium materials that is taken to calculate the weight ratio between the sodium materials and the source materials as described above is all based on those converted into Na₂O weight. Specifically, the sodium

materials may present as Na, Na₂O and the like in said alkaline inorganic

materials including sodium silicate, sodium hydroxide in powder form, liquid type water glass and liquid type sodium hydroxide. In this case, they are all converted into Na₂O weight for calculation. Therefore, when the sodium

materials are present as Na2θ weight, the weight is taken as it is, but for

the weight of the sodium materials that are present in a form other than Na2θ,

it is converted into Na₂O weight for calculation.

<57> As such, in order to obtain a cement-free alkali activated binder having desired strength, the weight of the alkaline inorganic materials is determined so as to appropriately control the weight ratio between the sodium materials and the source materials when the source materials and the alkaline inorganic materials are admixed with each other.

<58> In this case, when the source materials are blast furnace slag, the amount of the alkaline inorganic materials are adjusted so that the weight ratio between the sodium materials and the source materials can be within the range of 0.038 to 0.088.

<59> Further, when the source materials are fly ash or meta kaolin, the amount of the alkaline inorganic materials are adjusted so that the weight ratio between the sodium materials and the source materials can be within the range of 0.088 to 0.14.

<60> When liquid type sodium hydroxide is included in the alkaline inorganic materials that are to be incorporated in a cement-free alkali activated binder, sodium hydroxide solution having a concentration of 8 to 16M is used.

<6i> In the cement-free alkali activated binder of the present invention, a source material comprising at least any one of blast furnace slag, fly ash and meta kaolin, and the alkaline inorganic materials comprising at least any one of sodium silicate, sodium hydroxide in powder form, liquid type water glass and liquid type sodium hydroxide are admixed with each other. In this case, alumina or silica that are comprised in the source material and the sodium or potassium comprised in the alkaline inorganic material are molten and synthesized to give a solidified cement-free alkali activated binder of the present invention, as it is shown in the following chemical reaction 1. <62> [Chemical react ion 1]

n(Sl₂O₅, AI₂O₂) + 2nSiO₂ + 4nH₂O + NaOH or (KOH)

→Na⁺, K⁺ + n(0H)₃- ShAh-O-Si-(OH)₃

!

(OH)₂

<63>

<64> (wherein, any one of NaOH or KOH can be selected and mixed)

<65> Figure 1 and Figure 2 are the photos showing the cement-free alkali

activated binder according to the first example of the present invention.

<66> More specifically, Figure 1 is a photo which shows the cement-free

alkali activated binder in which blast furnace slag as a source material and

sodium silicate, sodium hydroxide and calcium sulfate as an alkaline

inorganic material are admixed with each other. Figure 2 is a photo which

shows the cement-free alkali activated binder in which fly ash as a source

material and sodium silicate, sodium hydroxide and calcium sulfate as an

alkaline inorganic material are admixed with each other.

<67> In this case, the cement-free alkali activated binder that are shown in

Figure 1 and Figure 2 have a specific gravity of 2.2 to 2.9 and specific

2 surface area of 400Og/cm , depending on the weight ratio between the sodium

materials and the source materials. <68> Figure 3 and Figure 4 are the photos showing flow of the mortar that is prepared with the cement-free alkali activated binder according to the example of the present invention.

<69> Herein after, ^JGBS means a ground granulated blast furnace slag that is obtained by fine pulverization of blast furnace slag to granules with a uniform size.

<70> Herein after, mortar means the mortar which has been produced under the conditions including that ratio of water/cement-free alkali activated binder (i.e., W/B) is 50% and the weight ratio of sand/the source material (i.e., S/B) is 3.0, and the maximum diameter of an aggregate is 5mm or less.

<7i> In Figure 3, flowability of the mortar, which has been produced by using cement-free alkali activated binder obtained from a source material such as blast furnace slag or fly ash and alkaline inorganic materials including at least any one of sodium silicate, sodium hydroxide in powder form, liquid type water glass and liquid type sodium hydroxide, is shown in accordance with the weight ratio between the sodium material and the source material .

<72> According to the results indicated in the graph of Figure 3, when the weight ratio between the sodium material and the source material is about 0.015, the initial flow was about 170mm or 180mm, respectively, for the cases having blast furnace slag or fly ash as a source material. In addition, when the weight ratio between the sodium material and the source material is about 0.06, the initial flow was about 200mm or 180mm, respectively, for the cases having blast furnace slag or fly ash as a source material.

<73> Further, while the weight ratio between the sodium material and the source material increases up to about 0.17, the initial flow decreases and it becomes dramatically reduced starting from the specific weight ratio (i.e., about 0.11) when the source material was blast furnace slag. On the other hand, initial flow gradually increases and it becomes stabilized starting from the specific weight ratio (i.e., about 0.08) when the source material was fly ash.

<74> Still further, it was found that, when the source material was fly ash the initial flow is higher than that of conventional Portland cement, regardless of the weight ratio between the sodium material and the source material. When the source material was blast furnace slag the initial flow is higher than that of conventional Portland cement only if the weight ratio between the sodium material and the source material is 0.06 or less.

<75> According to the results shown in the graph of Figure 4, when the weight ratio between the sodium material and the source material (in this case, the source material was blast furnace slag and fly ash) is 0.015 or 0.035, the initial flow in accordance with the change in the weight ratio between S1O2 and the sodium material is affected by the amount of sodium

hydroxide.

<76> In other words, the initial flow becomes higher as the amount of sodium hydroxide, which has an overall influence on the amount of the sodium materials, is smaller.

<77> As such, it was found that the mortar based on the cement-free alkali activated binder of the present invention has initial flow that is the same or greater than that required for application in actual field.

<78> Figures 5 to 8 are the graphs showing the compression strength after 28 days and the development of compression strength at different aging time of the mortar, that is prepared with the cement-free alkali activated binder according to the first example of the present invention, in accordance with the weight ratio between the sodium materials and the source materials.

<79> In Figure 5, the compression strength after 28 days increases as the weight ratio between the sodium materials and the source materials (when blast furnace slag was used as a source material) gradually increases. Specifically, when blast furnace slag was used as a source material, the compression strength was about 20MPa even when the weight ratio between the sodium materials and the source materials was 0.03795 (i.e., about 0.038).

<80> Figure 6 shows that the compression strength after 28 days tends to increase as the weight ratio between the sodium materials and the source materials (when fly ash was used as a source material) increases. Specifically, when the weight ratio between the sodium materials and the source materials was less than 0.08855, i.e., less than about 0.088, the compression strength after 28 days was IMPa or less, and when the ratio was the same or more than 0.088 the compression strength after 28 days was 4MPa or more.

<8i> Figure 7 indicates that, when the source material was blast furnace slag the compression strength at different aging time in accordance with the weight ratio between the sodium materials and the source materials is slightly lower than that of conventional Portland cement specifically when said weight ratio is about 0.038. However, when it is the same or greater than 0.06325, i.e., the same or greater than about 0.063, the mortar based on the cement-free alkali activated binder of the present invention has higher compression strength. Furthermore, it also shows that long term development of the strength is better than conventional Portland cement.

<82> In Figure 8, when the source material was fly ash the compression strength at different aging time in accordance with the weight ratio between the sodium materials and the source materials was excellently developed especially after 56 days. When the weight ratio between the sodium materials and the source materials was low, the compression strength was also low. However, when the weight ratio was 0.11385 (i.e., about 0.114), the compression strength was 16MPa (strength after 91days), and when the ratio was 0.13915 (i.e., about 0.14) the compression strength was 18MPa or more (strength after 91days), which is not lower than the compression strength of conventional Portland cement, so that it can be satisfactorily used in actual field of construction.

<83> Taken together the results and explanations regarding Figures 5 to 8, the cement-free alkali activated binder of the present invention can provide mortar having compression strength of 20MPa or more when the source material is blast furnace slag and the weight ratio between the sodium materials and the source materials is about 0.038 or more and said compression strength is satisfactory compared to those required in an actual construction field. Further, the cement-free alkali activated binder of the present invention can provide mortar having compression strength of 16MPa or more when the source material is fly ash and the weight ratio between the sodium materials and the source materials is about 0.114 or more and said compression strength is slightly lower or higher than that required for mortar that is used in an actual construction field, which is at the level of 20 to 30 MPa. Thus, it is found that the cement-free alkali activated binder of the present invention can be satisfactorily used in an actual construction field.

<84> In this case, since the amount of an alkaline inorganic material increases as the weight ratio between the sodium materials and the source materials becomes higher, when the source material is blast furnace slag it is preferable that the weight ratio between the sodium materials and the source materials is the same or less than 0.088. In addition, when the source material fly ash it is preferable that the weight ratio between the sodium materials and the source materials is the same or less than 0.14. This is because that initial flow decreases as the weight ratio between the sodium materials and the source materials becomes higher and due to high price of the alkaline inorganic materials such as sodium materials, price of the cement-free alkali activated binder of the present invention will be more expensive as more amount of inorganic materials is included in therein.

<85> Figure 9 and Figure 10 are the graphs showing the shrinkage strain of the mortar that is prepared with the cement-free alkali activated binder according to the first example of the present invention.

<86> In Figure 9, the shrinkage strain of the mortar that is prepared using blast furnace slag as a source material is lower than that of the mortar prepared using conventional Portland cement after aging for 14 days, when the

weight ratio between the sodium materials and the source materials is the

same or less than 0.139 (i.e., the same or less than about 0.14). In this

case, extreme shrinkage strain of the alkali activated mortar using blast

-6 furnace slag is about -900X10 or less.

<87> In Figure 10, the shrinkage strain of the mortar that is prepared using

fly ash as a source material is lower than that of the mortar prepared using

conventional Portland cement after aging for 14 days, when the weight ratio

between the sodium materials and the source materials is 0.114 or less. In

addition, even when the weight ratio between the sodium materials and the

source materials is 0.139 (i.e., about 0.14) or 0.164, the shrinkage strain

is almost at the same level as that of conventional Portland cement mortar.

In this case, extreme shrinkage strain of the alkali activated mortar using

-6 fly ash is also about -900X10 or less.

<88> Thus, the cement-free alkali activated binder of the present invention

comprises the source materials comprising at least any one of blast furnace

slag, fly ash and meta kaolin, and the alkaline inorganic materials

comprising at least any one of sodium silicate, sodium hydroxide in powder

form, liquid type water glass and liquid type sodium hydroxide. The cement- free alkali activated binder, which is a mixture of said source materials and the alkaline inorganic materials, preferably has a weight ratio between the sodium materials, which constitutes the alkaline inorganic materials, and the source materials of from 0.038 and 0.14.

<89> In this case, for the cement-free alkali activated binder of the present invention, weight ratio between the sodium materials and the source materials is preferably within the range of 0.038 to 0.088 when the source material is blast furnace slag, in view of the initial flow and the compression strength that are required in an actual construction field. Further, for the cement-free alkali activated binder of the present invention, weight ratio between the sodium materials and the source materials is preferably within the range of 0.114 to 0.14 when the source material is fly ash, in view of the initial flow and the compression strength that are required in an actual construction field.

<90> As described in the above, the present invention was illustrated and explained with reference to preferred examples. However, the present invention is not limited to the examples and it is evident that within the spirit of the present invention various changes and modifications can be made by a skilled person in the pertinent art.

<91> [Mode for Invention]

<92> [Second example]

<93> The method for producing cement-free alkali activated mortar according to the second example of the present invention is based on mixing of alkaline inorganic materials including sodium materials and source materials comprising at least any one of blast furnace slag, fly ash and meta kaolin, with water and sand to provide cement-free alkali activated mortar.

<94> In this case, the alkaline inorganic materials, which include sodium materials, comprise at least any one of sodium silicate, sodium hydroxide in powder form, liquid type water glass and liquid type sodium hydroxide.

<95> In this case, the alkaline inorganic materials may further comprise at least any one of potassium silicate, calcium sulfate and belite. These compounds of potassium silicate, calcium sulfate and belite are employed to increase the flowability and to control the shrinkage during the subsequent process of producing alkali activated mortar.

<96> The weight ratio between the alkaline inorganic materials and the source materials which constitute said alkaline inorganic materials is within the range of 0.038 to 0.14. Such weight ratio between the alkaline inorganic materials and the source materials determines the mechanical properties such as flowability, strength and the shrinkage strain and the like of the cement- free alkali activated binder of the present invention. Consequently, the mechanical properties of the cement-free alkali activated binder determine the mechanical properties of the cement-free alkali activated mortar that is produced by the method for producing the same of the present invention. <97> In this case, the alkaline inorganic materials, which include said sodium materials, comprise Na, Na2θ and the like. The weight of said alkaline

inorganic materials that is taken to calculate the weight ratio between the alkaline inorganic materials and the source materials is all based on those converted into Na₂O weight. Specifically, the alkaline inorganic materials

may present as Na, Na₂O and the like in said alkaline inorganic materials

including sodium silicate, sodium hydroxide in powder form, liquid type water glass and liquid type sodium hydroxide. In this case, the weight of Na comprised in said constituent was all converted into Na₂O weight for the

calculation. <98> In this case, when the source materials are blast furnace slag, the amount of the alkaline inorganic materials are adjusted so that the weight ratio between the alkaline inorganic materials and the source materials can be within the range of 0.038 to 0.088. <99> Moreover, when the source materials are fly ash or meta kaolin, the amount of the alkaline inorganic materials are adjusted so that the weight

ratio between the alkaline inorganic materials and the source materials can

be within the range of 0.088 to 0.14.

<ioo> In this case, when the liquid type sodium hydroxide is comprised in the

alkaline inorganic materials that are incorporated in the alkali activated

binder, a solution of sodium hydroxide having concentration of 8 to 16M is

used.

<ioi> The alkali activated binder in which blast furnace slag is used as a

source material can form CSH gel according to a reaction with water. On the

other hand, the alkali activated binder in which fly ash or meta kaolin is

used as a source material does not form CSH gel according to a reaction with

water. In addition, with the reaction between blast furnace slag or fly ash

and water, an alumina can be replaced by silica. As a result, the alkali

activated binder can be ultimately prepared depending on alkali quality index

in view of required strength.

<i02> In this case, the alkali quality index (Q_A) can be calculated from the

following equation,

Na₂O ( ^_{n «} , . _n *_r ~ \ BXbyweight)

<1O3> ⁶^^{2 Ah}°' ^Laυ . In the equation, B represents the total

weight of the source material and the alkaline inorganic materials that are used.

<iO4> For carrying out the method for producing cement-free alkali activated

mortar according to the present invention, when an alkali activated binder,

sand and water are mixed to prepare cement-free alkali activated mortar, the

alkali activated binder comprising the source materials and the alkaline

inorganic materials, sand and water are suitably selected so as to satisfy

the following Equations 1 to 3.

<iO5> The following equation 1 is to calculate initial flow (Fj) wherein the

parameters include alkali quality index (Q_A), ratio between water and alkali

activated binder (W/B), ratio between specific surface area of a source

material and basic specific surface area of a source material (S_A/S_AO) (in

2 this case, the basic specific surface area of a source material is 4000cm /g),

ratio between sand and alkali activated binder (S/B) and basic flow (F₀) (in

this case, said basic flow corresponds to 100mm). <1O6> [Equat ion 1]

<107>

<1O8> As such, once the initial flow value that is required for cement-free alkali activated mortar is decided, the weight ratio among the alkali activated binder comprising the source materials and the alkaline inorganic materials, water and sand, that is calculated from Equation 1 above is determined while considering Equation 2 and Equation 3 below. Further, by mixing the components in said determined weight ratio, cement-free alkali activated mortar is produced, and therefore cement-free alkali activated mortar having a desired initial flow value can be obtained.

<1O9> In addition, by incorporating each of mixing ratio, which can be obtained from compression strength after 28 days using Equation 2 or Equation 3 below or a model for the development of compression strength, to Equation 1 above, corresponding initial flow can be obtained. As a result, the initial flow according to combination with Equation 1 or Equation 3 below can be obtained.

<iio> The following equation 2 is for the calculation of compression strength after 28 days ((f_Ck)2s) wherein the parameters include alkali quality index

(Q_A), ratio between water and alkali activated binder (W/B), ratio between

specific surface area of a source material and basic specific surface area of

a source material (S_A/S_Ao) and ki.

<iπ> [Equation 2]

<112> ⁽/Ar^{148 [}

^*(/*^}o th

<ii3> The ki described in the above equation corresponds to the 0.5 power or

-0.5 power value of the ratio between sand and alkali activated binder

(S/A) . When the ratio between sand and alkali activated binder is the same

or less than 2.5, the value obtained from the calculation using (S/A) is

incorporated to Equation 2, while when it is more than 2.5 the value obtained

from the calculation using (S/A) is incorporated to Equation 2.

<ii4> In this case, the (f_Ck)o is a parameter which indicates basic

compression strength and it corresponds to 10MPa.

<U5> Thus, once the compression strength after 28 days that is required for

cement-free alkali activated mortar is decided, the weight ratio among the alkali activated binder comprising the source materials and the alkaline inorganic materials, water and sand, that is calculated from Equation 2 above is determined while considering Equation 1 and Equation 3 below. Further, by mixing the components in said determined weight ratio, cement-free alkali activated mortar is produced, and therefore cement-free alkali activated mortar having a desired compression strength after 28 days can be obtained.

<ii6> In addition, by incorporating each of mixing ratio, which can be obtained from initial strength using Equation 1 or Equation 3 below or a model for the development of compression strength, to Equation 2 above, corresponding compression strength after 28 days can be obtained. As a result, the compression strength after 28 days according to combination with Equation 1 or Equation 3 below can be obtained.

<ii7> The following equation 3 is for the calculation of a model for development of compression strength (i.e., compression strength according to different aging time, f_Ck(O) wherein the parameters include alkali quality

index (Q_A), ratio between water and alkali activated binder (W/B), ratio

between specific surface area of a source material and basic specific surface area of a source material (S_A/S_AQ) and k2. <ii8> [Equat ion 3]

<119>

<i20> In this case, the Ai corresponds to

and

<i2i> the Bi corresponds to

<122> With respect to k2, when the ratio between sand and alkali activated

binder (S/A) is the same or less than 2.5, the value obtained from the calculation using (1+S/A) is incorporated to Equation 3, while when it is

more than 2.5 the value obtained from the calculation using (1+S/A) is

incorporated to Equation 3.

<123> As such, once the model for development of compression strength that is required for cement-free alkali activated mortar is decided, the weight ratio among the alkali activated binder comprising the source materials and the alkaline inorganic materials, water and sand, that is calculated from Equation 3 above is determined while considering Equation 1 and Equation 2 above. Further, by mixing the components in said determined weight ratio, cement-free alkali activated mortar is produced, and therefore cement-free alkali activated mortar having a desired model for development of compression strength can be obtained.

<i24> In addition, by incorporating each of mixing ratio, which can be obtained from initial strength using Equation 1 or Equation 2 above or a model for the development of compression strength, to Equation 3 above, corresponding model for development of compression strength can be obtained. As a result, the model for development of compression strength according to combination with Equation 1 or Equation 2 above can be obtained.

<125> Figures 11 to 13 are the photos showing the cement-free alkali activated mortar that is prepared according to the method for the production of cement-free alkali activated mortar according to the second example of the present invention.

<126> More specifically, Figures 11 to 13 are the photos showing the cement- free alkali activated mortar that is prepared as a representative example based on the optimum mixing ratio indicated in Table 1 above. Figure 11 shows the cement-free alkali activated mortar wherein the ratio between water and an alkali activated binder is 50%, the ratio between sand and an alkali activated binder is 3.0 and the source material of the alkali activated binder is furnace blast slag. Figure 12 shows the cement-free alkali activated mortar wherein the ratio between water and an alkali activated binder is 50%, the ratio between sand and an alkali activated binder is 3.0 and the source material of the alkali activated binder is fly ash. Figure 13 shows the cement-free alkali activated mortar wherein the ratio between water and an alkali activated binder is 40%, the ratio between sand and alkali activated binder is 1.0 and the source material of the alkali activated binder is furnace blast slag.

<127> Figure 14 and Figure 15 are the graphs showing the flow of the cement- free alkali activated mortar, that is prepared according to the method for the production of cement-free alkali activated mortar according to the second example of the present invention, in accordance with the ratio between water and the alkali activated binder, or the flow of said mortar in accordance with the ratio between sand and the alkali activated binder.

<128> With respect to Figure 14, the graph of Figure 14 shows the flow of the cement-free alkali activated mortar that is prepared according to the method for the production of cement-free alkali activated mortar according to the second example of the present invention, in accordance with the ratio between water and the alkali activated binder, indicating that the flow value increases as the ratio between water and the alkali activated binder becomes higher.

<129> With respect to Figure 15, the graph of Figure 15 shows the flow of the cement-free alkali activated mortar that is prepared according to the method for the production of cement-free alkali activated mortar according to the second example of the present invention, in accordance with the ratio between sand and the alkali activated binder, indicating that the flow value decreases as the ratio between sand and the alkali activated binder becomes higher.

<13O> Consequently, it was found that, the flow value increases as the ratio between water and the alkali activated binder becomes higher while it decreases as the ratio between sand and the alkali activated binder becomes higher.

<131> Figure 16 and Figure 17 are the graphs showing the compression strength after 28 days of the cement-free alkali activated mortar, that is prepared according to the method for the production of the cement-free alkali activated mortar according to the second example of the present invention, in accordance with the weight ratio between water and the alkali activated binder, or the compression strength after 28 days of said alkali activated mortar in accordance with the ratio between sand and the alkali activated binder .

<132> With respect to Figure 16, the graph of Figure 16 shows the compression strength after 28 days of the cement-free alkali activated mortar that is prepared according to the method for the production of the cement-free alkali activated mortar according to the second example of the present invention, in accordance with the ratio between water and the alkali activated binder, indicating that the compression strength after 28 days decreases as the ratio of water becomes higher and the ratio of the alkali activated binder becomes 1ower.

<133> With respect to Figure 17, the graph of Figure 17 shows the compression strength after 28 days of the cement-free alkali activated mortar that is prepared according to the method for the production of the cement-free alkali activated mortar according to the second example of the present invention, in accordance with the ratio between sand and the alkali activated binder, indicating that the compression strength is the highest when the ratio between sand and the alkali activated binder is 2.5 and when it is 2.5 or more, the compression strength starts to decrease as the ratio between sand and the alkali activated binder becomes higher.

<i34> Taken together the results shown in the graphs of Figure 16 and Figure 17, it was found that, the compression strength after 28 days decreases as the ratio between water and the alkali activated binder becomes higher while the compression strength after 28 days increases as the ratio between sand and the alkali activated binder is increased to 2.5.

<135>

<136> [Third example]

<i37> The method for producing cement-free alkali activated reinforcement mortar according to the third example of the present invention is based on mixing of an alkali activated binder, which comprises blast furnace slag, an alkaline inorganic materials including sodium materials, calcium hydroxide, melamine water reducing agent and borate salt, with dry sand and water.

<i38> The dry sand used in the present invention has a maximum diameter of 5mm and it is admixed in a weight ratio of 2.5 compared to the cement-free alkali activated binder.

<139> Further, water is admixed in a weight ratio of 0.55 compared to the cement-free alkali activated binder.

<14O> The blast furnace slag that is mentioned in the above is used as a main component for preparing the cement-free alkali activated binder and it is a slag that is produced from a cast iron from iron ore.

<141> Thus, the cement-free alkali activated reinforcement mortar, that is produced according to the third example of the present invention, is environmentally friendly by recycling industrial wastes and it can be produced without using cement. <142> The alkaline inorganic materials are used to control the mechanical properties of mortar, including flowability, strength and the shrinkage strain and the like, when the mortar is produced from the alkali activated binder. <143> The alkaline inorganic materials include sodium materials that are Na or Na₂θ, and according to one example of the present invention sodium silicate

was used.

<144> Still, any alkaline inorganic materials which include sodium materials that are Na or Na₂θ can be used for the present invention.

<145> For instances, the alkaline inorganic materials can be sodium hydroxide in powder or liquid type or liquid type water glass. <146> Further, sodium silicate is added so as to obtain that the weight ratio of Na2θ, which is a sodium material comprised in the sodium silicate, is 6.4%

to 9% compared to the weight of the blast furnace slag. <147> In the alkaline inorganic materials, Na or Na₂θ may present as a sodium material. In this case, it was converted into Na₂O weight for calculation.

Therefore, when the sodium materials are present as Na₂θ the weight is taken

as it is, and for the weight of the sodium materials that are present in a form other than Na₂O, it is converted into Na₂O weight for calculation, and

added to obtain the Na₂O weight ratio of 6.4% to 9% compared to the weight of

the blast furnace slag. <148> Calcium hydroxide is added to determine the solidifying property of the cement-free alkali activated mortar that is produced according to one example of the present invention. Added in a weight ratio of 5% to 10 % compared to blast furnace slag, it can delay the solidification. <149> Borate salts are added to improve the flowability and reduce the compression strength of the mortar of the present invention. Specifically, it is added in a weight ratio of 1% to 5% compared to the weight of blast furnace slag. <15O> The melamine water reducing agent is added in a weight ratio of 0.5% to

2% compared to the weight of blast furnace slag, and it can improve the workability of the mortar. <i5i> Figure 18 is a graph showing initial flow of the cement-free alkali activated reinforcement mortar that is prepared according to the third example of the present invention. <i52> As it can be confirmed from Figure 18, the slump flow of the mortar having no borate salts was 118mm while it is improved to 165mm when the borate salts were added in an amount of 1%, indicating better initial flow. <153> Thus, having high initial flow, the mortar that is prepared according to the third example of the present invention is appropriate for the repair of buildings such as filling cracks of the buildings, etc. <154> Figure 19 is a graph showing flow loss of the cement-free alkali activated reinforcement mortar that is prepared according to the third example of the present invention. <i55> With respect to Figure 19, the slump flow after 30 minutes is about

180mm or about 205mm when 1% or 2% borate salts were added to the mortar, indicating an improvement over the initial slump flow of 165mm. <156> On the other hand, for the mortar having no borate salts, the slump flow reduced to 103mm after 30 minutes from the initial slump flow of 118mm, indicating a rapid solidification. <157> Thus, it was found that, having very little flow loss over time, the mortar that is prepared according to the third example of the present invention is highly suitable to be used as repair and reinforcement mortar. <158> Figure 20 is a graph showing compression strength of the cement-free alkali activated reinforcement mortar that is prepared according to the one example of the present invention.

<159> With respect to Figure 20, the compression strength after one day is 7.5MPa when no borate salts were added to the mortar, while it was reduced to 2.5MPa for the mortar in which 2% borate salts had been added.

<16O> In addition, from the results of the compression strength determined after 3 or 7 days, it was found that the compression strength was reduced by about 7MPa and about 5MPa, respectively, for the mortar having 2% borate salts compared to the mortar without them.

<i6i> Thus, it was found that, having low compression strength, the mortar that is prepared with the cement-free alkali activated binder according to the third example of the present invention can be solidified with flexibility when it is used for repair of cracks in buildings.

<162> Herein above, the constitution and the function of the present invention were described in view of the above explanation and the drawings. However, it is evident that they are only for the exemplification of the present invention, and without departing from the technical spirit and the scope of the present invention, various changes and modification can be made. [Industrial Applicability]

<163> According to the present invention, a cement-free alkali activated binder that is not only environmentally friendly as being capable of dramatically reducing the carbon dioxide emission, which has been remained as a problem for producing Portland cement, but also has an excellent property, a method for producing mortar using the same and a method for producing cement-free alkali activated reinforcement mortar are provided and they can be advantageously used in an actual construction field.

Claims

[CLAIMS]

[Claim 1]

<166> A cement-free alkali activated binder, characterized in that it comprises source materials comprising at least any one of blast furnace slag, fly ash and meta kaolin; and alkaline inorganic materials including sodium materials.

[Claim 2]

<167> The cement-free alkali activated binder according to Claim 1, characterized in that said alkaline inorganic materials comprise at least any one of sodium silicate, sodium hydroxide in powder form, liquid type water glass and liquid type sodium hydroxide.

<168>

[Claim 3]

<169> The cement-free alkali activated binder according to Claim 1 or Claim 2, characterized in that said sodium materials are either Na or Na₂θ.

<170>

[Claim 4]

<171> The cement-free alkali activated binder according to Claim 2, characterized in that said liquid type sodium hydroxide has concentration of 8 to 16M.

<172>

[Claim 5]

<173> The cement-free alkali activated binder according to Claim 1 or Claim 2, characterized in that weight ratio between the sodium materials and the source materials is from 0.038 to 0.14.

<174>

[Claim 6]

<175> The cement-free alkali activated binder according to Claim 5, characterized in that weight ratio between the sodium materials and the source materials is from 0.038 to 0.088 when the source materials are blast furnace slag.

<176>

[Claim 7]

<177> The cement-free alkali activated binder according to Claim 5, characterized in that weight ratio between the sodium materials and the source materials is from 0.114 to 0.14 when the source materials are fly ash.

<178>

[Claim 8] <179> The cement-free alkali activated binder according to Claim 1 or Claim 2, characterized in that the alkaline inorganic materials further comprise at least any one of potassium silicate, calcium sulfate and belite.

<180>

[Claim 9]

<i8i> The cement-free alkali activated binder according to Claim 1 or Claim 2, characterized in that alumina or silica that are comprised in the source materials is solidified by melting and synthesis with the sodium materials comprised in the alkaline inorganic materials.

<182>

[Claim 10]

<183> A method for producing cement-free alkali activated mortar, characterized in that it comprises a step of mixing an alkali activated binder which comprises alkaline inorganic materials including sodium materials and source materials comprising at least any one of blast furnace slag, fly ash and meta kaolin; water, and; sand.

<184>

[Claim 11]

<185> The method for producing cement-free alkali activated mortar according to Claim 10, characterized in that the alkaline inorganic materials comprise at least any one of sodium silicate, sodium hydroxide in powder form, liquid type water glass and liquid type sodium hydroxide.

<186>

[Claim 12]

<187> The method for producing cement-free alkali activated mortar according to Claim 11, characterized in that the sodium materials are either Na or Na2U.

<188>

[Claim 13]

<189> The method for producing cement-free alkali activated mortar according to Claim 11, characterized in that the alkaline inorganic materials further comprise at least any one of potassium silicate, calcium sulfate and belite.

<190>

[Claim 14]

<i9i> The method for producing cement-free alkali activated mortar according to Claim 10, characterized in that weight ratio between the alkaline inorganic materials and the source materials is from 0.038 to 0.14.

<192>

[Claim 15]

<193> The method for producing cement-free alkali activated mortar according to Claim 14, characterized in that weight ratio between the sodium materials and the source materials is from 0.038 to 0.088 when the source mater ials are blast furnace slag.

<194>

[Claim 16]

<195> The method for producing cement-free alkali activated mortar according to Claim 14, characterized in that weight ratio between the sodium materials and the source materials is from 0.114 to 0.14 when the source materials are fly ash.

<196>

[Claim 17]

<197> A method for producing cement-free alkali activated reinforcement mortar, characterized in that the cement-free alkali activated reinforcement mortar is produced by mixing a cement-free alkali activated binder, which comprises blast furnace slag, alkaline inorganic materials including sodium materials, calcium hydroxide, melamine water reducing agent and borate salt, with dry sand and water.

<198>

[Claim 18]

<199> The method for producing cement-free alkali activated reinforcement mortar according to Claim 17, characterized in that the borate salt is comprised in a weight ratio of 1% to 5% compared to the blast furnace slag.

<200>

[Claim 19]

<20i> The method for producing cement-free alkali activated reinforcement mortar according to Claim 17 or Claim 18, characterized in that calcium hydroxide is comprised in a weight ratio of 5% to 10% compared to the blast furnace slag.

<202>

[Claim 20]

<203> The method for producing cement-free alkali activated reinforcement mortar according to Claim 19, characterized in that the sodium materials are either Na or Na2θ.

<204>

[Claim 21]

<205> The method for producing cement-free alkali activated reinforcement mortar according to Claim 20, characterized in that the alkaline inorganic materials are sodium silicate and Na2θ, which is the sodium material of the

sodium silicate, is comprised in a weight ratio of 6.4% to 9% compared to the blast furnace slag. [Claim 22] The method for producing cement-free alkali activated reinforcement mortar according to Claim 21, characterized in that the melamine water reducing agent is comprised in a weight ratio of 0.5% to 2% compared to the blast furnace slag.