Strengthening agent for geopolymer compositions and geopolymer compositions

Abstract

To provide a strength enhancement aid for a geopolymer composition, capable of imparting high initial strength and long-term strength to a hardened product of a geopolymer composition.SOLUTION: A strength enhancement aid for a geopolymer composition includes at least one kind of a compound selected from a group consisting of an alkaline earth metal oxide, an inorganic calcium salt analog, an inorganic aluminum salt, a nitrate or a nitrite analog, and an organic strength enhancement component.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a strength-enhancing agent for geopolymer compositions and a geopolymer composition comprising the strength-enhancing agent for the geopolymer composition. [Background technology]

[0002] In recent years, there has been a growing demand to reduce carbon dioxide emissions in the construction sector as we strive to achieve a decarbonized society. Water-curing compositions, such as concrete and mortar, which are widely used in construction, contain large amounts of cement, which releases significant amounts of carbon dioxide during their manufacturing process. Therefore, in order to reduce carbon dioxide emissions in the construction sector, the development of alternative water-curing compositions to replace cement is required.

[0003] Therefore, geopolymer compositions that can be hardened without using cement have been proposed. Geopolymers are substances formed by the polycondensation of an active filler containing alumina and silicic acid and an alkaline activator. Various studies are currently being conducted on compounds to be used as active fillers and compounds to be used as alkaline activators. For example, in order to reduce environmental impact through the effective utilization of waste, coal ash such as fly ash, various types of fly ash, blast furnace slag fine powder, silica fume, etc., are sometimes used as active fillers.

[0004] Therefore, a hardening composition has been proposed that does not use any cement at all, using blast furnace slag powder, slaked lime, and optionally fly ash or silica fume as a binder, and further blending this binder with a high-performance AE water-reducing agent such as a polycarboxylic acid, and optionally a water-soluble admixture mainly composed of multiple inorganic compounds such as calcium ions, magnesium ions, sodium ions, and alkali metal ions, and clean water (Patent Document 1). Patent Document 1 states that desired initial strength and durability can be obtained and that it is particularly applicable to porous concrete, etc.

[0005] However, the hardening composition described in Patent Document 1 had room for improvement in its initial strength, which is required for general hardened concrete and affects the timing of formwork removal, at around 1 day of age.

[0006] Furthermore, geopolymer compositions have the problem of having a short fluidity retention time due to their rapid hardening. Therefore, a geopolymer composition has been proposed that further incorporates orthophosphate into an alkaline solution containing fly ash, blast furnace slag powder, water glass, and aggregate (Patent Document 2). Patent Document 2 states that the fluidity retention time can be extended to about 30 to 60 minutes.

[0007] However, for geopolymer compositions to be widely applied as an alternative to conventional cement concrete, there was room for improvement in extending the fluidity retention time of geopolymer compositions containing orthophosphates. Furthermore, for geopolymer compositions to be widely used like general cement concrete, it is preferable that additives be easily added to the geopolymer composition (for example, it is desirable to add them in liquid form), and it is also preferable that the geopolymer composition has the required performance characteristics to facilitate handling, such as low viscosity, suppression of separation, or suppression of shrinkage after hardening. [Prior art documents] [Patent Documents]

[0008] [Patent Document 1] Japanese Patent Publication No. 2012-171855 [Patent Document 2] Japanese Patent Publication No. 2020-026357 [Overview of the project] [Problems that the invention aims to solve]

[0009] In view of the above circumstances, the present invention aims to provide a strength-enhancing agent for geopolymer compositions that can impart high initial strength and long-term strength to the cured product of a geopolymer composition, and a geopolymer composition that has a long fluidity retention time in its fresh state, while having high initial strength and long-term strength in its cured state. [Means for solving the problem]

[0010] The gist of the present invention is as follows: [1] Alkaline earth metal oxides, inorganic calcium salts, inorganic aluminum salts, (sub) A strength-enhancing aid for geopolymer compositions comprising at least one compound selected from the group consisting of nitrates and organic strength-enhancing components. [2] Strength-enhancing aid for geopolymer compositions according to [1], wherein the alkaline earth metal oxide is at least one selected from the group consisting of magnesium oxide, calcium oxide, strontium oxide, and barium oxide. [3] Strength-enhancing aid for geopolymer compositions according to [1] or [2], wherein the inorganic calcium salts are at least one selected from the group consisting of calcium hydroxide, gypsum, calcium carbonate, calcium phosphate, calcium aluminate, and calcium chloride. [4] Strength-enhancing aid for geopolymer compositions according to any one of [1] to [3], wherein the inorganic aluminum salts are at least one selected from the group consisting of sodium aluminate and aluminum sulfate. [5] The above (sub) Strength-enhancing aid for geopolymer compositions according to any one of [1] to [4], wherein the nitrates are at least one selected from the group consisting of alkaline earth metal nitrates and alkaline earth metal nitrites. [6] The strength-enhancing aid for geopolymer compositions according to any one of [1] to [5], wherein the organic strength-enhancing component is at least one selected from the group consisting of glycerols and alkanolamines. [7] A geopolymer composition comprising an active filler, an alkaline activator, a condensate-based dispersant, and a strength-enhancing aid for geopolymer compositions according to any one of [1] to [6]. [8] The active filler is fly ash and blast furnace slag fine powder The geopolymer composition according to [7], comprising at least one selected from the group consisting of the following. [9] The geopolymer composition according to [7] or [8], wherein the alkaline activator comprises at least one selected from the group consisting of alkali silicate and alkali hydroxide.

[10] The condensate-based dispersant comprises at least one selected from the group consisting of beta-naphthaleneformaldehyde condensates, condensates having a polyallyl ether structure, and condensates containing at least the following constituent units A), B), C), and D), The geopolymer composition according to any one of [7] to [9], wherein the content of the condensate-based dispersant is 0.5 parts by mass or more and 1.5 parts by mass or less per 100 parts by mass of the active filler. A) Polyethylene glycol monophenyl ether of the following formula (I) [ka] [In the formula, m is an integer between 3 and 280.] B) Cyclic compounds having at least one hydroxyl group and their derivatives C) Phenoxyethyl derivatives containing phenol, polyethylene glycol monophenyl ether with 1 or 2 repeating units of ethylene oxide, or phosphate or phosphonate. D) Aldehydes.

[11] The geopolymer composition according to any one of [7] to

[10] , wherein the strength-enhancing aid for the geopolymer composition contains the alkaline earth metal oxide.

[12] The geopolymer composition according to

[11] , wherein the content of the alkaline earth metal oxide is 1.0 part by mass or more and 15 parts by mass or less per 100 parts by mass of the active filler.

[13] The geopolymer composition according to any one of [7] to

[12] , wherein the content of fumed silica in 100% by mass of the active filler is 20% by mass or less.

[14] The geopolymer composition according to any one of [7] to

[13] , wherein the content of fumed silica in 100% by mass of the active filler is 5.0% by mass or less.

[15] The geopolymer composition according to any one of [7] to

[14] , wherein the active filler does not contain fumed silica.

[16] The geopolymer composition according to any one of [7] to

[15] , further comprising a thickener and / or a bleeding inhibitor.

Advantages of the Invention

[0011] According to an aspect of the strength enhancing aid for the geopolymer composition of the present invention, by containing at least one compound selected from the group consisting of alkaline earth metal oxides, inorganic calcium salts, inorganic aluminum salts, (sub) nitrate salts and organic strength enhancing components, high initial strength and long-term strength can be imparted to the cured product of the geopolymer composition.

[0012] According to an aspect of the strength enhancing aid for the geopolymer composition of the present invention, when the alkaline earth metal oxide is at least one selected from the group consisting of magnesium oxide, calcium oxide, strontium oxide and barium oxide,

[0013] According to an embodiment of the geopolymer composition of the present invention, by including an active filler, an alkaline activator, a condensate-based dispersant, and a strength-enhancing aid for the geopolymer composition, a geopolymer composition can be obtained that has a long fluidity retention time in its fresh state, while having high initial strength and long-term strength in its cured state. Therefore, in the geopolymer composition of the present invention, since it has a long-term fluidity retention time in its fresh state, it is possible to transport and pump it for long periods of time, improving handling during on-site concrete placement. Furthermore, in the geopolymer composition of the present invention, since it has sufficient initial strength and long-term strength in its cured state, it is possible to remove the formwork early and ensure the structural strength over a long period of time.

[0014] According to an embodiment of the geopolymer composition of the present invention, the active filler is fly ash and blast furnace slag. fine powder By including at least one selected from the group consisting of the above, it is possible to reduce the environmental burden through the effective utilization of waste, and to easily manufacture geopolymer compositions.

[0015] According to an embodiment of the geopolymer composition of the present invention, by including at least one alkali activator selected from the group consisting of alkali silicate and alkali hydroxide, a polycondensate of an active filler containing alumina and silicic acid and an alkali activator can be easily and reliably obtained.

[0016] According to an embodiment of the geopolymer composition of the present invention, the condensate-based dispersant comprises a beta-naphthaleneformaldehyde condensate, a condensate having a polyallyl ether structure, and at least the following constituent units A), B), C), and D) A) Polyethylene glycol monophenyl ether of the following formula (I) [ka] [In the formula, m is an integer between 3 and 280.] B) Cyclic compounds having at least one hydroxyl group and their derivatives C) Phenoxyethyl derivatives containing phenol, polyethylene glycol monophenyl ether with 1 or 2 repeating units of ethylene oxide, or phosphate or phosphonate. D) Aldehydes The geopolymer composition contains at least one selected from the group consisting of condensates, and the content of the condensate-based dispersant is 0.5 parts by mass or more and 1.5 parts by mass or less per 100 parts by mass of the active filler, thereby reliably reducing the viscosity of the geopolymer composition in its fresh state, and thus ensuring a long flow retention time.

[0017] According to an embodiment of the geopolymer composition of the present invention, the strength-enhancing aid for the geopolymer composition contains the alkaline earth metal oxide, and the content of the alkaline earth metal oxide is 1.0 part by mass or more and 15 parts by mass or less per 100 parts by mass of the active filler, thereby ensuring that the strength of the geopolymer composition is reliably increased while ensuring a long fluidity retention time.

[0018] According to an embodiment of the geopolymer composition of the present invention, by not including silica fume in the active filler, it is possible to reliably obtain a long fluidity retention time while reducing the manufacturing cost of the geopolymer composition. [Modes for carrying out the invention]

[0019] The strength-enhancing agent for geopolymer compositions and the geopolymer composition of the present invention will be described in detail below. First, the strength-enhancing agent for geopolymer compositions of the present invention will be described in detail.

[0020] <Strength-enhancing agent for geopolymer compositions> The strength-enhancing agent for geopolymer compositions of the present invention is added to a geopolymer composition to assist in improving the initial strength and / or long-term strength of the geopolymer composition, and is an alkaline earth metal oxide, an inorganic calcium salt, an inorganic aluminum salt, (sub)It contains at least one compound selected from the group consisting of nitrates and organic strength-enhancing components. These compounds may be used alone or in combination of two or more. The strength-enhancing aid for geopolymer compositions of the present invention contains alkaline earth metal oxides, inorganic calcium salts, inorganic aluminum salts, (sub) By incorporating at least one compound selected from the group consisting of nitrates and organic strength-enhancing components into a geopolymer composition, high initial strength and long-term strength can be imparted to the cured geopolymer composition. In this specification, "initial strength" refers to the strength of the cured geopolymer composition 24 hours after preparation, and "long-term strength" refers to the strength of the cured geopolymer composition 28 days after preparation. Furthermore, in this specification, "()nitrites" means nitrates and / or nitrites. Furthermore, the strength-enhancing agent for geopolymer compositions of the present invention is easy to add to geopolymer compositions and facilitates the handling of geopolymer compositions. In addition, geopolymer compositions to which the strength-enhancing agent for geopolymer compositions of the present invention has been added possess generally required properties such as moderately low viscosity, suppression of separation of components of the geopolymer composition, and suppression of shrinkage after curing.

[0021] Alkaline earth metal oxides Alkaline earth metal oxides, in combination with the active fillers incorporated into the geopolymer composition of the present invention (described later), can improve the initial and long-term strength of the geopolymer composition. The alkaline earth metal oxide used as a strength-enhancing aid for the geopolymer composition is not particularly limited, but it is preferably at least one selected from the group consisting of magnesium oxide (MgO), calcium oxide (CaO), strontium oxide (SrO), and barium oxide (BaO) in order to reliably impart high initial and long-term strength to the cured geopolymer composition. Magnesium oxide (MgO) and calcium oxide (CaO) are more preferred, and calcium oxide (CaO) is particularly preferred, in order to reliably impart high initial strength to the cured geopolymer composition while being easy to handle. These alkaline earth metal oxides may be used alone or in combination of two or more.

[0022] The content of alkaline earth metal oxides in the geopolymer composition is not particularly limited, but the lower limit is preferably 1.0 part by mass, more preferably 1.5 parts by mass, and particularly preferably 2.0 parts by mass, per 100 parts by mass (solids, hereinafter the same) of active filler blended into the geopolymer composition, in order to reliably increase the strength of the geopolymer composition. On the other hand, the upper limit of the content of alkaline earth metal oxides in the geopolymer composition is preferably 15 parts by mass, more preferably 10 parts by mass, and even more preferably 5.0 parts by mass, per 100 parts by mass of active filler blended into the geopolymer composition, in order to reliably prevent inhibition of the reaction of the active filler and a decrease in the strength-enhancing effect, and to reliably obtain a long fluidity retention time, and particularly preferably 3.0 parts by mass, in order to reliably prevent high temperature in the pre-curing state of the geopolymer composition and reliably prevent cracking in the cured product of the geopolymer composition, as well as in terms of ease of addition and measurement and cost reduction.

[0023] Inorganic calcium salts Inorganic calcium salts, in combination with the active fillers incorporated into the geopolymer composition of the present invention (described later), can improve the initial and long-term strength of the geopolymer composition. The inorganic calcium salts used as strength-enhancing aids for the geopolymer composition are not particularly limited, but it is preferable that they be at least one selected from the group consisting of calcium hydroxide, gypsum, calcium carbonate, calcium phosphate, calcium aluminate, and calcium chloride, in order to reliably impart high initial and long-term strength to the cured product of the geopolymer composition. Calcium hydroxide, gypsum, calcium carbonate, and calcium chloride are more preferable in terms of ease of handling, and calcium hydroxide and gypsum are particularly preferable. These inorganic calcium salts may be used alone or in combination of two or more.

[0024] The content of inorganic calcium salts in the geopolymer composition is not particularly limited, but the lower limit is preferably 1.0 part by mass, more preferably 1.5 parts by mass, and particularly preferably 2.0 parts by mass, per 100 parts by mass of active filler incorporated into the geopolymer composition, in order to reliably increase the strength of the geopolymer composition. On the other hand, the upper limit of the content of inorganic calcium salts in the geopolymer composition is preferably 15 parts by mass, more preferably 10 parts by mass, and particularly preferably 5.0 parts by mass, per 100 parts by mass of active filler incorporated into the geopolymer composition, in order to reliably obtain a long fluidity retention time.

[0025] Inorganic aluminum salts Inorganic aluminum salts, in combination with the active fillers incorporated into the geopolymer composition of the present invention (described later), can improve the initial and long-term strength of the geopolymer composition. While the inorganic aluminum salts used as strength-enhancing aids for the geopolymer composition are not particularly limited, it is preferable that they be at least one selected from the group consisting of sodium aluminate and aluminum sulfate, as this reliably imparts high initial and long-term strength to the cured geopolymer composition. The inorganic aluminum salts may be anhydrous or hydrated. Furthermore, the inorganic aluminum salts may contain small amounts of iron ions and may form complexes. These inorganic aluminum salts may be used individually or in combination of two or more.

[0026] The content of inorganic aluminum salts in the geopolymer composition is not particularly limited, but the lower limit is preferably 1.0 part by mass, more preferably 1.5 parts by mass, and particularly preferably 2.0 parts by mass, per 100 parts by mass of active filler incorporated into the geopolymer composition, in order to reliably increase the strength of the geopolymer composition. On the other hand, the upper limit of the content of inorganic aluminum salts in the geopolymer composition is preferably 20 parts by mass, more preferably 15 parts by mass, even more preferably 10 parts by mass, and particularly preferably 5.0 parts by mass, per 100 parts by mass of active filler incorporated into the geopolymer composition, in order to reliably obtain a long fluidity retention time.

[0027] (sub) Nitrates (sub) Nitrates, in combination with the active fillers incorporated into the geopolymer composition of the present invention (described later), can improve the initial and long-term strength of the geopolymer composition. They are used as strength-enhancing aids for geopolymer compositions. (sub) While the nitrates are not particularly limited, it is preferable that they be at least one selected from the group consisting of alkaline earth metal nitrates and alkaline earth metal nitrites, with calcium nitrate and calcium nitrite being particularly preferred, as they can reliably impart high initial strength and long-term strength to the cured product of the geopolymer composition. (sub)Nitrates may be in anhydrous or hydrated form. (sub) Nitrates may be used individually or in combination of two or more types. (sub) Nitrates may be used alone as strength-enhancing agents for geopolymer compositions, but it is preferable to use them in combination with alkaline earth metal oxides, inorganic calcium salts, and / or inorganic aluminum salts.

[0028] (sub) The content of nitrates in the geopolymer composition is not particularly limited, but the lower limit is preferably 1.0 part by mass, more preferably 1.5 parts by mass, and particularly preferably 2.0 parts by mass, per 100 parts by mass of active filler blended into the geopolymer composition, in order to reliably contribute to increasing the strength of the geopolymer composition. On the other hand, (sub) The upper limit of the nitrate content in the geopolymer composition is preferably 10 parts by mass, and particularly preferably 5.0 parts by mass, per 100 parts by mass of active filler blended into the geopolymer composition, in order to ensure a long fluidity retention time.

[0029] Organic strength-enhancing components The organic strength-enhancing component, in combination with the active filler incorporated into the geopolymer composition of the present invention (described later), can improve the initial and long-term strength of the geopolymer composition. The organic strength-enhancing component used as a strength-enhancing aid for the geopolymer composition is not particularly limited, but it is preferably at least one selected from the group consisting of glycerin compounds and alkanolamines, as this can reliably impart high initial and long-term strength to the cured product of the geopolymer composition. Examples of glycerin compounds include glycerin, diglycerin, polyglycerin, and their alkylene oxide adducts. Examples of alkanolamines include diethanolamine, triethanolamine, and triisopropanolamine. These organic strength-enhancing components may be used alone or in combination of two or more. Furthermore, while the organic strength-enhancing component may be used alone as a strength-enhancing aid for the geopolymer composition, it is preferable to use it in combination with alkaline earth metal oxides, inorganic calcium salts, and / or inorganic aluminum salts.

[0030] The content of the organic strength-enhancing component in the geopolymer composition is not particularly limited, but the lower limit is preferably 0.010 parts by mass, more preferably 0.015 parts by mass, and particularly preferably 0.020 parts by mass, per 100 parts by mass of active filler blended into the geopolymer composition, in order to reliably enhance the strength of the geopolymer composition. On the other hand, the upper limit of the content of the organic strength-enhancing component in the geopolymer composition is preferably 5.0 parts by mass, more preferably 3.0 parts by mass, and particularly preferably 1.0 part by mass, per 100 parts by mass of active filler blended into the geopolymer composition, in order to reliably obtain a long fluidity retention time.

[0031] <Geopolymer composition> Next, the geopolymer composition of the present invention will be described in detail. The geopolymer composition of the present invention comprises an active filler, an alkaline activator, a condensate-based dispersant, and the above-mentioned strength-enhancing aid for geopolymer compositions. By including the active filler, alkaline activator, condensate-based dispersant, and the above-mentioned strength-enhancing aid for geopolymer compositions of the present invention, it is possible to obtain a geopolymer composition that has a long fluidity retention time in its fresh state, while having high initial strength and long-term strength in its cured state. Therefore, in the fresh state, the geopolymer composition of the present invention has a long fluidity retention time, allowing for long-term transportation and pumping, and improving handling during on-site placement. Furthermore, in the cured state, the geopolymer composition of the present invention has sufficient initial strength and long-term strength, allowing for the early removal of the cured geopolymer composition from the formwork, and ensuring structural strength over a long period of time.

[0032] Each component of the geopolymer composition of the present invention is described below.

[0033] Activated filler When the activated filler comes into contact with the alkaline activator described later, metal ions eluted from the activated filler crosslink with the silica structure of the activated filler, causing dehydration condensation polymerization. The activated filler functions as a binder for the geopolymer composition. The activated filler is not particularly limited as long as it can carry out the above reaction, and examples include fly ash, bottom ash, rice husk ash, palm ash obtained by calcining oil palm residue, waste glass, municipal solid waste incineration ash, sewage sludge incineration ash, blast furnace slag fine powder, metakaolin (calcined clay mineral), silica fume, powdered silica, etc. These may be used alone or in combination of two or more. Of these, fly ash and blast furnace slag fine powder are preferred because they can reduce environmental burden through the effective utilization of waste, allow for easy production of the geopolymer composition, and are readily available and easy to handle.

[0034] The active filler may or may not contain silica fume. In other words, the geopolymer composition of the present invention may or may not contain silica fume. By not including silica fume in the active filler, that is, by not including silica fume in the geopolymer composition of the present invention, it is possible to reduce the manufacturing cost of the geopolymer composition while reliably obtaining a long fluidity retention time.

[0035] When the active filler contains silica fume, the upper limit of the silica fume content in 100% by mass of the active filler (solid content, hereinafter the same) is preferably 20% by mass, more preferably 10% by mass, from the viewpoint of preventing an increase in the viscosity of the geopolymer composition and more reliably obtaining handling properties in a fresh state, and particularly preferably 5.0% by mass, from the viewpoint of reliably preventing a decrease in the fluidity of the geopolymer composition and reducing costs. On the other hand, the lower limit of the silica fume content in 100% by mass of the active filler is preferably 1.0% by mass, particularly preferably 2.0% by mass, from the viewpoint of reliably preventing a decrease in the fluidity of the geopolymer composition. It is preferable to add the silica fume to the geopolymer composition in powder or slurry form in combination with other active fillers. It is preferable that the silica fume and powdered silica have a silica component of 90% or more.

[0036] The activated filler is preferably free of cement clinker, as this ensures carbon dioxide reduction and reliable acquisition of high initial and long-term strength.

[0037] Fly Ash (FA) Fly ash is industrial waste generated at coal-fired power plants. Fly ash is rich in silica (SiO2) and alumina (Al2O3). In the geopolymer composition of the present invention, any quality of fly ash can be used, whether or not it conforms to the JIS standard. There are four types of fly ash (Fly Ash Type I to Type IV) used in the geopolymer composition of the present invention. Fly ash specified in JIS is preferred, and Type II fly ash (JIS Type II ash) is particularly preferred in terms of further increasing the strength of the cured product. In addition, ASTM Type F and Type C fly ash are preferred for use in the geopolymer composition of the present invention.

[0038] The fly ash content is not particularly limited, but the lower limit is 100 kg / m³, from the standpoint of facilitating the hardening of the geopolymer mortar. 3 Preferably, 200 kg / m 3 This is particularly preferable. On the other hand, the upper limit of the fly ash content is 700 kg / m³, in order to prevent an increase in viscosity of the fresh geopolymer composition and to obtain excellent handling properties. 3 Preferably, 500 kg / m 3 That is particularly preferable.

[0039] Blast furnace slag fine powder (BS) Blast furnace slag fine powder Blast furnace slag is a by-product obtained in the process of manufacturing pig iron from iron ore, by recovering components other than iron contained in the iron ore, along with the ash from the auxiliary raw materials, limestone and coke. Blast furnace slag fine powder is obtained by adjusting the particle size by crushing blast furnace slag or the like. Blast furnace slag fine powder is not particularly limited as long as it is used in ordinary geopolymer compositions, and can be appropriately selected according to the usage conditions, etc. Examples of blast furnace slag fine powder include blast furnace slag fine powder used in JIS R 5211 "Blast Furnacement" and blast furnace slag fine powder conforming to JIS A 6206 "Blast Furnace Fine Powder for Concrete".

[0040] The content of blast furnace slag fine powder is not particularly limited, but the lower limit is 50 kg / m³, in terms of imparting excellent fluidity to the fresh geopolymer composition. 3 Preferably, 100 kg / m 3 This is particularly preferable. On the other hand, the upper limit for the content of blast furnace slag fine powder is 400 kg / m³ in order to ensure a long fluidity retention time. 3 Preferably, 350 kg / m 3That is particularly preferable.

[0041] When the active filler contains fly ash and blast furnace slag fine powder, the mass ratio of fly ash to blast furnace slag fine powder in the active filler is not particularly limited, but from the viewpoint of facilitating the dehydration condensation polymerization reaction by the alkaline activator, 5:1 to 1:5 is preferred, and 3:1 to 1:1 is particularly preferred. Furthermore, when the active filler contains fly ash and blast furnace slag fine powder, from the viewpoint of facilitating the curing of the geopolymer composition, the total amount of fly ash and blast furnace slag fine powder is preferably 90% by mass or more.

[0042] Alkaline activator Alkaline activators have the function of eluting metal ions from the active filler, crosslinking the silica structure of the active filler with the eluted metal element, and causing the active filler to undergo dehydration condensation polymerization. Alkaline activators are solutions containing alkali metals such as lithium (Li), sodium (Na), and potassium (K). They may also contain other components as needed. As alkaline activators, alkali silicate and alkali hydroxide are preferred because they allow for easy and reliable acquisition of polycondensates of the active filler containing alumina and silicic acid with the alkaline activator, and are readily available.

[0043] The content of the alkaline activator is not particularly limited, but its lower limit is preferably 3.0 parts by mass and particularly preferably 4.0 parts by mass per 100 parts by mass of active filler, from the viewpoint of smoothly dehydrating and condensing the active filler. On the other hand, the upper limit of the alkaline activator content is preferably 6.0 parts by mass and particularly preferably 5.0 parts by mass per 100 parts by mass of active filler, from the viewpoint of facilitating the curing of the geopolymer composition.

[0044] Condensate-based dispersants The condensate-based dispersant has the function of reducing the viscosity of the geopolymer composition of the present invention and providing a long fluidity retention time in its fresh state. As the condensate-based dispersant, for example, beta-naphthaleneformaldehyde condensate and condensate having a polyallyl ether structure are preferred because they can reliably reduce the viscosity of the geopolymer composition in its fresh state and reliably provide a long fluidity retention time.

[0045] Furthermore, other condensate-based dispersants include, for example, those that can reliably reduce the viscosity of the geopolymer composition in its fresh state and reliably provide a long fluidity retention time, at least the following constituent units A), B), C), and D) A) Polyethylene glycol monophenyl ether of the following formula (I) [ka] [In the formula, m is an integer between 3 and 280.] B) Cyclic compounds having at least one hydroxyl group and their derivatives C) Phenoxyethyl derivatives containing phenol, polyethylene glycol monophenyl ether with 1 or 2 repeating units of ethylene oxide, or phosphate or phosphonate. D) Aldehydes A condensate containing the above is preferred.

[0046] Constituent unit B is a cyclic compound having at least one hydroxyl group and its derivatives. Specific examples of constituent unit B include at least one aromatic compound selected from the group consisting of benzene-1,2-diol, benzene-1,2,3-triol, 2-hydroxybenzoic acid, 2,3-dihydroxybenzoic acid, 3,4-dihydroxybenzoic acid, 3,4,5-trihydroxybenzoic acid, 3-hydroxyphthalic acid, 2,3-dihydroxybenzenesulfonic acid, 3,4-dihydroxybenzenesulfonic acid, 1,2-dihydroxynaphthalene, 2,3-dihydroxynaphthalene, 1,2-dihydroxynaphthalene-5-sulfonic acid, 1,2-dihydroxynaphthalene-6-sulfonic acid, 2,3-dihydroxynaphthalene-5-sulfonic acid, 2,3-dihydroxynaphthalene-6-sulfonic acid, and mixtures thereof.

[0047] The constituent unit C is a phenoxyethyl derivative containing phenol, polyethylene glycol monophenyl ether with 1 or 2 repeating units of ethylene oxide, or phosphate or phosphonate. Specific examples of constituent unit C include at least one other aromatic compound selected from the group consisting of phenol, 2-phenoxyethanol, 2-phenoxyethyl phosphate, 2-phenoxyethyl phosphonate, 2-phenoxyacetic acid, 2-(2-phenoxyethoxy)ethanol, 2-(2-phenoxyethoxy)ethyl phosphate, 2-(2-phenoxyethoxy)ethyl phosphonate, 2-[-(2-hydroxyethoxy)phenoxy]ethyl phosphate, 2-[4-(2-hydroxyethoxy)phenoxy]ethyl phosphonate, 2-[4-(2-phosphonatooxyethoxy)phenoxy]ethyl phosphate, 2-[4-(2-phosphonatooxyethoxy)phenoxy]ethyl phosphonate, methoxyphenol, and mixtures thereof.

[0048] The constituent unit D is an aldehyde. Specific examples of constituent unit D include formaldehyde, paraformaldehyde, glyoxylic acid, benzaldehyde, benzaldehyde sulfonic acid, benzaldehyde disulfonic acid, vanillin, isovanillin, and at least one aldehyde selected from the group consisting of these.

[0049] The condensate-based dispersants described above may be used alone or in combination of two or more. The content of the condensate-based dispersant is not particularly limited, but the lower limit is preferably 0.5 parts by mass, and particularly preferably 0.7 parts by mass, per 100 parts by mass of active filler, in order to reliably reduce the viscosity of the geopolymer composition in its fresh state and reliably provide a long fluidity retention time. On the other hand, the upper limit of the content of the condensate-based dispersant is preferably 1.5 parts by mass, and particularly preferably 1.3 parts by mass, in order to reliably prevent setting delay and reliably obtain excellent initial strength.

[0050] Strengthening agent for geopolymer compositions The geopolymer composition of the present invention contains, as described above, alkaline earth metal oxides, inorganic calcium salts, inorganic aluminum salts, (sub) The geopolymer composition contains a strength-enhancing agent for geopolymer compositions comprising at least one compound selected from the group consisting of nitrates and organic strength-enhancing components. Details of the strength-enhancing agent for geopolymer compositions incorporated into the geopolymer composition of the present invention are as described above.

[0051] Other ingredients In the geopolymer composition of the present invention, other components commonly used in concrete compositions may be added as needed, depending on the usage conditions. Examples of other components include fine aggregate, coarse aggregate, fibers, water, thickeners, bleeding inhibitors, air-entraining agents, retarders, and the like.

[0052] Examples of thickening agents include inorganic derivatives such as clay and talc, acrylic or acrylamide (co)polymers, natural polysaccharides such as celluloses and gums, and compounds having a thickening effect such as polysaccharide derivatives. Examples of bleeding inhibitors include, in addition to the above thickening agents, polyalkylene oxides, superabsorbent polymers, and amine salts.

[0053] The thickening agent also has the effect of suppressing water separation. The lower limit of the thickening agent content in the geopolymer composition is preferably 0.001% by mass, in order to reliably suppress water separation. On the other hand, the upper limit of the thickening agent content in the geopolymer composition is preferably 1.0% by mass, in order to reliably prevent a decrease in handling properties due to an increase in the viscosity of the geopolymer composition.

[0054] The lower limit of the mass ratio of water (W) to active filler (P) (hereinafter sometimes referred to as "W / P") is preferably 20%, and particularly preferably 25%, from the viewpoint of reliably preventing a decrease in handling properties due to an increase in the viscosity of the geopolymer composition. On the other hand, the upper limit of W / P is preferably 40%, and particularly preferably 35%, from the viewpoint of facilitating the curing of the geopolymer composition. Hereinafter, W means the mass of all water contained in the geopolymer composition, including the water added as described above, the water contained in the alkaline activator, and the surface water of the aggregate, and P means the mass of all active fillers contained in the geopolymer composition. In other words, W / P means the mass ratio obtained by dividing the mass of all water contained in the geopolymer composition by the mass of all active fillers contained in the geopolymer composition.

[0055] <Method for producing geopolymer compositions> The method for producing the geopolymer composition of the present invention is not particularly limited and can be produced using conventional geopolymer composition production methods. Furthermore, the apparatus used for producing the geopolymer composition can also be the same as that used for conventional geopolymer composition production. [Examples]

[0056] Next, embodiments of the present invention will be described, but the present invention is not limited to the following embodiments.

[0057] <Synthesis of condensate-based dispersants> 621.8 parts of 2-phenoxyethanol were packed into a heatable reactor equipped with a stirrer and a metering pump under nitrogen at 20°C. Then, 449.7 parts of polyphosphate were added over 100 minutes under cooling, ensuring the temperature did not exceed 35°C. After metering, the reaction mixture was stirred for a further 15 minutes at approximately 70°C, transferred before solidification, and 2-phenoxyethyl phosphate was obtained.

[0058] In a heatable reactor equipped with a stirrer and a metering pump, 300 parts of poly(ethylene oxide) monophenyl ether (average molecular weight 2000 g / mol), 46.2 parts of 3,4-dihydroxybenzoic acid, 33 parts of 2-phenoxyethyl phosphate, and 19.9 parts of paraformaldehyde were packed under nitrogen at 90°C. This reaction mixture was heated to 110°C with stirring, and then 41 parts of methanesulfonic acid (70%) were added within 25 minutes, ensuring that the reaction temperature did not exceed 115°C. After metering, this reaction mixture was stirred further at 110°C for 2.5 hours. After cooling, it was mixed with 350 parts of water, heated to 100°C for 30 minutes, neutralized with 50% caustic soda solution to a pH of approximately 7.0, and polymer 1 with a solid content of 20% by mass was obtained.

[0059] <Formulation of geopolymer composition> The constituent components of the geopolymer compositions in the examples, reference examples, and comparative examples are shown in Table 1 below.

[0060] [Table 1]

[0061] Using the compounding ingredients shown in Table 1, geopolymer compositions of the examples, reference examples, and comparative examples were produced. Specifically, half of the fine aggregate, the reactive filler, the strength enhancement aid (strength enhancement aid for geopolymer composition), and half of the fine aggregate were put into a container in this order, and kneaded for 20 seconds. Then, the condensate-based dispersant, water, and alkali activator were added, kneaded for 60 seconds, scraping (the operation of putting the powder adhering to the wall surface into the center of the container) was performed, and kneaded for 120 seconds to obtain a geopolymer composition. The compounding amounts of each component blended in the geopolymer composition are shown in Table 2 below. Note that the reference example is a sample in which, as the strength enhancement aid (strength enhancement aid for geopolymer composition), fumed silica that has been conventionally used is blended instead of calcium oxide.

[0062]

Table 2

[0063] The numerical values of the compounding amounts in Table 2 indicate the compounding amounts in 1 m 3 of the geopolymer composition in kg units. However, the addition amount of calcium oxide is the part by mass of calcium oxide with respect to 100 parts by mass of the solid reactive filler. Also, the addition amounts of the alkali activator and the condensate-based dispersant are parts by mass with respect to 100 parts by mass of the solid reactive filler.

[0064] The evaluation items are as follows. (1) Flow value (mm) Measured in accordance with JIS R 5201. However, the flow value without performing 15 blows of tamping was used.

[0065] (2) Compressive strength (MPa) Measured in accordance with JIS A 1108. The test specimen size was a cylinder with a diameter of φ5 and a height of 10. The compressive strength after 1 day was evaluated that if it was 5.0 MPa or more, the formwork could be removed early and was judged as qualified. Also, the compressive strength after 28 days was evaluated that if it was 50.0 MPa or more, the strength of the long-term structure could be ensured and was judged as qualified.

[0066] The measurement results of flow values ​​and compressive strengths for the geopolymer compositions of the examples, reference examples, and comparative examples are shown in Table 3 below.

[0067] [Table 3]

[0068] As shown in Table 3 above, in the geopolymer compositions of Examples 1 and 2, which contained calcium oxide instead of silica fume as a strength-enhancing agent for geopolymer compositions, the compressive strength after 1 day was 5.0 MPa or higher, and the compressive strength after 28 days was 50.0 MPa or higher, demonstrating that not only high long-term strength but also high initial strength was achieved. Therefore, in Examples 1 and 2, it was possible to reduce manufacturing costs compared to the conventional geopolymer composition in Reference Example 1 while obtaining the same initial and long-term strength as the conventional one. Furthermore, in the geopolymer compositions of Examples 1 and 2, which contained a condensate-based dispersant, the flow value from immediately after mixing to 120 minutes was 300 mm, indicating that high fluidity was maintained for a long period in the fresh state. The geopolymer compositions of Examples 1 and 2 showed superior flow values ​​from immediately after mixing to 120 minutes compared to the conventional geopolymer composition.

[0069] On the other hand, in Comparative Example 1, the geopolymer composition, which did not contain calcium oxide, a strength-enhancing agent for geopolymer compositions, was unable to demold the mold after one day due to the weak strength of the cured geopolymer composition, and therefore the compressive strength could not be measured. Consequently, high initial strength could not be obtained in Comparative Example 1. [Industrial applicability]

[0070] The strength-enhancing agent for geopolymer compositions of the present invention can impart high initial strength and long-term strength to the cured geopolymer composition. The geopolymer composition of the present invention has a long fluidity retention time in its fresh state, while having high initial strength and long-term strength in its cured state, making it highly valuable for use in the construction field.

Claims

1. A geopolymer composition comprising an active filler, an alkaline activator, a condensate-based dispersant, and a strength-enhancing agent for geopolymer compositions, The active filler comprises at least one selected from the group consisting of fly ash and blast furnace slag fine powder. The aforementioned alkaline activator comprises at least one selected from the group consisting of alkali silicate and alkali hydroxide. The strength-enhancing agent for the geopolymer composition is selected from calcium oxide, and the content of the strength-enhancing agent for the geopolymer composition is 1.0 part by mass or more and 5.0 parts by mass or less per 100 parts by mass of the active filler. The aforementioned condensate-based dispersant includes a condensate comprising at least the following constituent units A), B), C), and D), A geopolymer composition in which the content of the condensate-based dispersant is 0.5 parts by mass or more and 1.5 parts by mass or less per 100 parts by mass of the active filler. A) Polyethylene glycol monophenyl ether of the following formula (I) 【Chemistry 1】 [In the formula, m is an integer between 3 and 280.] B) Cyclic compounds having at least one hydroxyl group and their derivatives C) Phenoxyethyl derivatives containing phenol, polyethylene glycol monophenyl ether with 1 or 2 repeating units of ethylene oxide, or phosphate or phosphonate. D) Aldehydes.

2. The geopolymer composition according to claim 1, wherein the silica fume content in 100% by mass of the active filler is 20% by mass or less.

3. The geopolymer composition according to claim 1, wherein the silica fume content in 100% by mass of the active filler is 5.0% by mass or less.

4. The geopolymer composition according to claim 1, wherein the active filler does not contain silica fume.

5. Furthermore, the geopolymer composition according to any one of claims 1 to 4, further comprising a thickening agent and / or a bleeding inhibitor.

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