CN116600960A

CN116600960A - Ready-mixed factory-like rapid hardening concrete material and ready-mixed factory-like rapid hardening concrete composition

Info

Publication number: CN116600960A
Application number: CN202180062634.8A
Authority: CN
Inventors: 相泽一裕; 原启史
Original assignee: Denka Co Ltd
Current assignee: Denka Co Ltd
Priority date: 2020-09-18
Filing date: 2021-09-03
Publication date: 2023-08-15
Also published as: WO2022059519A1; JPWO2022059519A1

Abstract

The invention relates to a double-component ready-mixed factory-like rapid hardening concrete material, which comprises a material A and a material B, wherein the material A comprises cement, a rapid hardening material and a dormancy agent, the material B comprises an aluminum sulfate hardening accelerator, the aluminum sulfate hardening accelerator comprises aluminum sulfate, and the stoichiometric ratio of the dormancy agent to the aluminum sulfate is 0.5-5.

Description

Ready-mixed factory-like rapid hardening concrete material and ready-mixed factory-like rapid hardening concrete composition

Technical Field

The invention relates to a ready-mixed factory-like fast-hardening concrete material and a ready-mixed factory-like fast-hardening concrete composition.

Background

From a world perspective, the production of cement is increasing and infrastructure refurbishment is rapidly evolving. In particular, the construction climax in China and southeast Asia is continued. In infrastructure truing, road truing is an important location. Since early opening of roads is desired at the time of new construction and repair, materials that can be used early are also required as materials to be used. As an example thereof, quick setting concrete is exemplified.

As a required property of the rapid hardening concrete, usable time is also an important property. In consideration of the time taken for manufacturing the ready-mixed concrete in the ready-mixed factory, transporting to the construction site, and constructing, and the cleaning time of the mixer truck as the ready-mixed concrete transporting truck, it is desirable to ensure a usable time of at least 120 minutes and at least 180 minutes as much as possible. However, ensuring a long pot life delays the curing time, and thus fails to meet the required strength at short ages. Therefore, in the prior art, it is difficult to satisfy the strength manifestation required for the initial age while securing a sufficient usable time.

At present, the actual situation is to prepare quick-hardening concrete at a construction site. In the construction of small casting quantity, 0.1-0.2 m ³ The left and right mixers mix the quick-hardening concrete, and the preparation and pouring of the quick-hardening concrete are carried out by using sea warfare. In this method, a lot of labor is required, man-hours are increased, cost is high, and there is a limit in the volume of the quick-setting concrete that can be supplied. In addition, in the construction with a large casting amount, the rapid hardening concrete is continuously supplied using a concrete traveling vehicle. However, in this method, there are also the following problems: in addition to the necessity of arranging a concrete traveling vehicle, the man-hours of loading the flexible container bag with fine aggregate and coarse aggregate, the moisture of which is managed to be constant, in advance, and carrying them to the site, or loading the flexible container bag with quick-setting cement, carrying them to the site, and preparing them, and the like, are increased, and the cost of the quick-setting concrete is remarkably increased. In addition, there is a limit in the preparation of concrete trucks.

Today, development of quick-setting concrete capable of leaving a ready-mix factory is strongly desired. If the quick-setting concrete can be shipped from a ready-mix factory, a large amount of the quick-setting concrete can be supplied to a construction site by directly using existing kneading equipment and a conveying system.

For example, patent document 1 discloses a ready-mix factory-type rapid-hardening concrete material using a ready-mix factory-type rapid-hardening concrete hardener containing at least 1 selected from the group consisting of calcium hydroxide, calcium carbonate, a calcium aluminate-based compound, a calcium silicate-based compound, colloidal silica, portland cement, calcium sulfoaluminate cement, and blast furnace slag.

Prior art literature

Patent literature

Patent document 1: international publication No. 2018/154890

Disclosure of Invention

Problems to be solved by the invention

According to the ready-mixed factory-like rapid hardening concrete material of patent document 1, a ready-mixed factory-like rapid hardening concrete composition excellent in initial strength performance while securing a sufficient usable time can be produced.

However, patent document 1 discloses a case where when aluminum sulfate is used as an accelerator, transient junction occurs, and the usable time cannot be ensured. Aluminum sulfate is an accelerator excellent as sodium aluminate, alkali metal hydroxide, and the like, but unlike these, aluminum sulfate is also excellent in handleability, and is said to be a material having high practicality. Further, aluminum sulfate is available in either a liquid state or a solid state, and therefore, is highly practical in that the form can be selected according to the place and situation of the construction.

In view of the foregoing, an object of the present invention is to provide a ready-mixed factory-like rapid hardening concrete composition which has excellent initial strength performance and high practicality while securing a sufficient usable time. The present invention also provides a ready-mixed and factory-like rapid hardening concrete material suitable for producing the ready-mixed and factory-like rapid hardening concrete composition.

Means for solving the problems

The present inventors have made various efforts to solve the above problems, and as a result, have found that a practical rapid hardening concrete composition excellent in initial strength performance can be prepared while securing a sufficient pot life by preparing a concrete in which an a material containing cement, a rapid hardening material and a dormancy agent is mixed, transporting the concrete to a site, and adding and mixing in a B material containing an aluminum sulfate-based hardening accelerator, and thus have completed the present invention. Namely, the present invention is as follows.

[1] A ready-mixed factory-like rapid hardening concrete material comprising a material A and a material B, wherein the material A comprises cement, a rapid hardening material and a dormancy agent, the material B comprises an aluminum sulfate-based hardening accelerator, the aluminum sulfate-based hardening accelerator comprises aluminum sulfate, and the stoichiometry ratio of the dormancy agent represented by the following formula (1) to the aluminum sulfate is 0.5 to 5;

formula (1): stoichiometric ratio = mass of aluminum sulfate (mol) x number of aluminum x valence of aluminum ion/(mass of retarder in the dormant agent (mol) x valence of retarder ion in the dormant agent).

[2] The two-component ready-mixed factory-like rapid hardening concrete material according to [1], wherein the aluminum sulfate-based hardening accelerator further comprises magnesium and calcium, and the content of the magnesium and the calcium is 0.007 to 4 parts by mass in terms of oxide based on 100 parts by mass of the aluminum sulfate.

[3] A ready-mixed factory-like rapid hardening concrete composition comprising a material A and a material B, wherein the material A contains cement, a rapid hardening material and a dormancy agent, the material B contains an aluminum sulfate-based hardening accelerator, the aluminum sulfate-based hardening accelerator contains aluminum sulfate, and the stoichiometric ratio of the dormancy agent represented by the following formula (1) to the aluminum sulfate is 0.5 to 5;

Effects of the invention

According to the present invention, a ready-mixed factory-like rapid hardening concrete composition having high practicality and excellent initial strength performance while securing a sufficient usable time can be provided. In addition, a ready-mixed factory-like rapid hardening concrete material suitable for producing the ready-mixed factory-like rapid hardening concrete composition can be provided.

Detailed Description

Hereinafter, embodiments of the present invention will be described in detail, but the present invention is not limited to the embodiments. In the present specification, "parts" and "%" are mass references unless otherwise specified. In the present specification, the composition refers to a generic term for a cement composition, a mortar composition, and a concrete composition.

[1] Premixed factory-leaving type rapid hardening concrete material

The ready-mixed factory-like rapid hardening concrete material of the present embodiment is composed of at least two components including an a material and a B material, wherein the a material contains cement, a rapid hardening material and a dormancy agent, the B material contains an aluminum sulfate-based hardening accelerator, and the aluminum sulfate-based hardening accelerator contains aluminum sulfate.

The term "ready-mix factory-like rapid hardening concrete" as used in the present embodiment means concrete which is transported by a mixer truck or the like after a ready-mix material (ready-mix concrete) is mixed at a ready-mix site, ready-mix factory or the like, and which is cured relatively rapidly after a pouring operation after leaving the factory to a construction site such as a civil engineering site or a construction site. In the case of ready-mixed factory-like quick-setting concrete, the minimum usable time from factory to completion of the work is 120 minutes or more due to the relationship of the conveyance time, and in the case of a long conveyance distance, it is desirable to secure a usable time of 180 minutes or more. This embodiment may be dedicated to such use.

The term "mixer truck" refers to a cargo truck that can be transported while mixing a premix, and that includes a mixing drum (mixing vessel) at a loading base portion, and has a maximum loading capacity of 2 to 26t, and its functions are not greatly different and are used differently depending on the application.

In the present embodiment, the dormancy agent in the material a is in a state where ready-mixed and factory-like rapid hardening concrete is dormant, that is, in a state where hydration hardening is substantially stopped. Thereby, the usable time can be ensured. In addition, by adding the aluminum sulfate-based hardening accelerator to the material B, the hydration hardening of the resting rapid hardening concrete is again awakened at the construction site by adding a large amount of the resting agent. Further, other components such as a rapid hardening material can provide excellent initial strength performance.

The setting and hardening are performed by adding the B material, but even after adding the B material, it is necessary to ensure a working time, and it is necessary to ensure a usable time of at least 15 minutes or longer. However, aluminum sulfate exhibits transient junction properties at a normal addition amount, and a sufficient usable time cannot be ensured. In contrast, in the present embodiment, the stoichiometric ratio of the dormancy agent to aluminum sulfate was studied, and by setting the range to 0.5 to 5, a sufficient usable time was ensured, and excellent initial strength expression was achieved.

Further, since aluminum sulfate is excellent in operability and can be used in either a liquid state or a solid state (preferably, powder) as described above, the form thereof can be selected according to the construction site and situation, and the like, and the practicability is high.

Hereinafter, the material B and the material a will be described in detail.

[ Material B ]

The aluminum sulfate-based hardening accelerator in the material B is a substance containing aluminum sulfate as a main component (preferably 70% or more, more preferably 80% or more) as a hardening accelerator component.

In the material B, the presence of a substance (other component) other than the hardening accelerator can also enhance the dispersibility of the aluminum sulfate-based hardening accelerator and promote the effect of the aluminum sulfate-based hardening accelerator, and therefore, the substance (other component) other than the hardening accelerator may be contained in a range of 30% or less as long as the effect of the present invention is not inhibited.

The aluminum sulfate of the present embodiment has the general formula Al ₂ (SO ₄ ) ₃ ·nH ₂ O (n=0 to 18), wherein n is in the range of 0 to 18. As the aluminum sulfate, there are anhydrous aluminum sulfate and aluminum sulfate having various amounts of crystal water, and any one may be used in the present invention.

Aluminum sulfate may be used as a powdery material or a material which is dissolved in water to prepare a liquid state. When aluminum sulfate is in a liquid state, the B material is also in a liquid state, and when aluminum sulfate is in a powder state, the B material is also in a powder state.

Among them, in particular, when good mixing with cement concrete is required and dust generation is prevented, it is preferable to use the cement concrete in a liquid form such as an aqueous solution. The concentration of aluminum sulfate in this case is preferably 10 to 40%, more preferably 20 to 30, in terms of solid content (anhydrous substance). By setting the content to 10 to 40%, the storage stability is improved, and the setting and hardening of the cement concrete can be prevented from being excessively promoted.

The term "liquid" also includes a substance in the form of a slurry or a substance in the form of a suspension.

In particular, when extremely high initial strength is required, aluminum sulfate is preferably a powder.

Aluminum sulfate may not be pulverized when it is 14 or more hydrate, and preferably 12 or less hydrate. In addition, since the coagulation property of anhydrous salt may be lowered, it is preferably 4 or more. More preferably 4 to 12, i.e. more preferably aluminum sulfate is a hydrate and the amount of water of hydration is 4 to 12.

The amount of the hydration water may be adjusted by, for example, heating aluminum sulfate of 18 water salts to dehydrate the aluminum sulfate to a desired amount of the hydration water.

The particle size of the aluminum sulfate is not limited, but it is usually preferably aluminum sulfate passing through a 1.2mm sieve, more preferably aluminum sulfate passing through a 0.6m sieve, and is difficult to dissolve in the form of a lump.

The aluminum sulfate-based hardening accelerator contains magnesium and calcium, and the content thereof is preferably 0.007 to 4 parts by mass, more preferably 0.01 to 2 parts by mass, in terms of oxide, per 100 parts by mass of aluminum sulfate. By 0.007 to 4 parts, sufficient adhesion can be imparted even in a normal-temperature to low-temperature environment, and a significant decrease in long-term strength in a high-temperature environment can be prevented. In addition, the initial strength performance can be maintained to be good.

The term "low temperature" in the low temperature environment "means 5 ℃ or lower, and the term" high temperature "in the high temperature environment" means 25 ℃ or higher.

Here, when the B material is in a liquid state, examples of the form in which magnesium and calcium are contained in the aluminum sulfate-based hardening accelerator include a form in which a compound containing magnesium and calcium, respectively, is dissolved in the liquid B material, and the content of magnesium and calcium is 0.007 to 4 parts in terms of oxide relative to 100 parts of aluminum sulfate.

In order to set the content of magnesium and calcium to the above range, the magnesium compound and the calcium compound may be dissolved in a predetermined amount.

In the case where the material B is in the form of powder, examples of the form in which magnesium and calcium are contained in the aluminum sulfate-based hardening accelerator include forms in which magnesium and calcium are contained in aluminum sulfate and the content thereof is 0.007 to 4 parts in terms of oxide relative to 100 parts of aluminum sulfate.

In order to form a state in which magnesium and calcium are contained in aluminum sulfate, when aluminum hydroxide and sulfuric acid are mixed to produce aluminum sulfate, a compound such as CaO and/or MgO contained in sulfuric acid is brought into a desired range, or a compound such as CaO and MgO is intentionally mixed into aluminum hydroxide and sulfuric acid to bring into a desired range, and the mixture is heated to react the mixture.

In this case, although CaO and MgO were confirmed together with aluminum sulfate in the fluorescent X-ray analysis, only a broad peak of aluminum sulfate was confirmed in the analysis by X-ray diffraction (XRD), and no peak was confirmed that can identify CaO and MgO. That is, although the aluminum sulfate contains calcium and magnesium, it can be regarded as substantially the same as aluminum sulfate.

Whether the material B is in a liquid or powder form, magnesium and calcium are preferably contained as oxides (MgO, caO), the CaO content in the material B is preferably 0.005 to 2%, and the MgO content is preferably 0.002 to 2%. The CaO content is more preferably 0.01 to 1.5%, and the MgO content is more preferably 0.008 to 1.5%.

If the CaO content is 0.005% or more, the long-term strength is more easily obtained under high temperature conditions, and if it is 2% or less, the decrease in coagulation property is easily suppressed. Further, when the MgO content is 0.002% or more, the long-term strength is more easily obtained in a high temperature condition, and when it is 2% or less, abnormal expansion is easily suppressed in a high temperature condition.

In this embodiment, as described above, the stoichiometric ratio of aluminum sulfate to a dormancy agent described later is studied, and the range is set to 0.5 to 5, whereby a sufficient usable time is ensured, and excellent initial strength performance is achieved. The stoichiometric ratio is represented by the following formula (1).

The expression (1) means that in concrete containing a rapid hardening material and a dormancy agent, the ratio of aluminum sulfate as a hardening accelerator to the dormancy agent is in the range of 0.5 to 5, and if the ratio is too low, the dormancy agent is too much to be rapidly hardened, and if the ratio is too high, the hardening accelerator is too much to cause transient junction.

Formula (1): stoichiometric ratio = mass of aluminum sulfate (mol) x number of aluminum x valence of aluminum ion/(mass of retarder in dormant agent (mol) x valence of retarder ion in dormant agent)

The stoichiometric ratio will be described below by taking as an example the case of using aluminum sulfate as the material B and potassium carbonate and citric acid (potassium carbonate: citric acid=75:25 (mass ratio)) as the dormancy agent of the material a.

First, the molar masses of aluminum sulfate and citric acid are as follows.

Aluminum sulfate (Al) ₂ (SO ₄ ) ₃ )：M.W.＝342.2

Citric acid (C) ₆ H ₈ O ₇ )：M.W.＝192.1

If the concrete contains 1% aluminum sulfate and 1.5% dormancy agent per 500kg of the binding material in the concrete, the respective components in the concrete are as follows. The hardening accelerator acts on citric acid as a retarder of the dormancy agent.

Aluminum sulfate: binding material 500000g×0.01 (=1%)/342.2=14.6 mol

Citric acid: binding material 500,000g×0.015 (=1.5%) ×0.25 (=25%)/192.1=9.7 mol

The aluminum ion functions as a 3-valent acid, and there are 2 pieces of Al in aluminum sulfate, and the citric acid ion is a 3-valent base (valence of retarder ion=3), so the above formula (1) is calculated as follows.

Formula (1): stoichiometric ratio= (14.6×2×3)/(9.7×3) =3.0

[ Material A ]

The material A contains cement, quick hardening material and dormancy agent.

(dormancy agent)

The dormancy agent used in the present embodiment has a function of dormancy (substantially stopping hydration hardening) of the rapid hardening concrete delivered from the ready-mix material, and avoids rapid hardening failure in the ready-mix factory and rapid hardening failure during transportation by a mixer truck. Examples of the dormancy agent include hydroxycarboxylic acids or salts thereof, or combinations of these with alkali metal carbonates, saccharides, boric acid, and the like. Wherein the retarder corresponds to hydroxycarboxylic acid or its salt, saccharide, and boric acid.

Among the above, hydroxycarboxylic acids and alkali metal carbonates are preferably used in combination from the viewpoint of the great effect of setting the rapid hardening concrete and the excellent strength performance after the addition of the B material. However, alkali metal carbonates other than lithium are preferably selected. It is necessary to ensure a sufficient usable time of the base concrete, and also to ensure a certain usable time even after the addition of the B material, and further to improve the strength performance, and from this point of view, it is not preferable to use lithium carbonate. In addition, in the case where only an alkali metal carbonate is used in combination with the hydroxycarboxylic acid, the alkali metal carbonate does not act as a dormancy agent.

In the present specification, the base concrete means a concrete obtained by kneading at least cement, a rapid hardening material, a dormancy agent, an aggregate, and kneading water.

The dormancy agent preferably contains a hydroxycarboxylic acid, a mixture of an alkali metal carbonate other than lithium and a hydroxycarboxylic acid, and more preferably contains a mixture of an alkali metal carbonate other than lithium and a hydroxycarboxylic acid. The mixing ratio of the alkali metal carbonate other than lithium to the hydroxycarboxylic acid is preferably 10/90 to 90/10, more preferably 20/80 to 80/20, in terms of alkali metal carbonate/hydroxycarboxylic acid.

Examples of the hydroxycarboxylic acid include hydroxycarboxylic acids or salts thereof, examples of the hydroxycarboxylic acids include citric acid, gluconic acid, tartaric acid, and malic acid, and examples of the salts thereof include sodium salt, potassium salt, calcium salt, and magnesium salt. 1 or 2 or more of them may be used in combination.

The content of the dormancy agent is preferably 0.3 to 5 parts, more preferably 0.3 to 4.5 parts, based on 100 parts of the total of the cement and the rapid hardening material. By setting the amount to 0.3 to 5 parts, a sufficient working time can be easily ensured in addition to the transportation time to the site. In addition, hydration hardening is easily caused again when the B material is added.

(fast hardening Material)

The rapid hardening material of the present embodiment is preferably composed of a calcium aluminate compound and a gypsum-based material. Here, the calcium aluminate compound means a compound composed of CaO and Al ₂ O ₃ The general term of the compound as the main component is not particularly limited. Specific examples thereof include CaO and Al ₂ O ₃ 、12CaO·7Al ₂ O ₃ 、11CaO·7Al ₂ O ₃ ·CaF ₂ 、3CaO·Al ₂ O ₃ 、3CaO·3Al ₂ O ₃ ·CaSO ₄ With CaO and Al ₂ O ₃ Amorphous material as main body (e.g. CaO-Al ₂ O ₃ -SiO ₂ A compound of the formula (I). Among them, from the viewpoint of strength expression, an amorphous substance is preferably selected.

Here, the amorphous degree in the present embodiment is defined as follows. The target material was annealed at 1000 ℃ for 2 hours, and then cooled slowly at a cooling rate of 5 ℃/min to crystallize. Then, the crystallized material was measured by powder X-ray diffraction method to determine the area S of the main peak of the crystallized mineral ₀ . Next, from the main peak area S of the crystals of the material before annealing, the amorphous degree X was obtained by the following formula.

X(％)＝100×(1-S/S ₀ )

The general industrial raw material contains SiO ₂ 、MgO、Fe ₂ O ₃ 、TiO ₂ 、K ₂ O、Na ₂ O, etc., but these impurities also promote the amorphization of the calcium aluminate compound, and the total amount thereof may be present in a range of 20% or less. Among them, siO is preferable for the purpose of obtaining amorphous calcium aluminate ₂ The presence of (2) may be contained in the range of 1 to 18%.

Thus, as a quickHard materials, preferably containing CaO-Al ₂ O ₃ -SiO ₂ A compound of the group consisting of CaO-Al and gypsum ₂ O ₃ -SiO ₂ The amorphous degree of the compound is 70% or more, and SiO ₂ In the range of 1 to 18 mass%. More preferably CaO-Al ₂ O ₃ -SiO ₂ The amorphous degree of the compound is 80% or more, and SiO ₂ In the range of 2 to 13 mass%.

The calcium aluminate compound is preferably adjusted to 3000 to 9000cm in terms of Bo's specific surface area by pulverization treatment ² Preferably 4000 to 8000cm ² And/g. By making the powder degree (Bo's specific surface area) of the calcium aluminate compound 4000-9000 cm ² And/g, a sufficient quick hardening property is easily obtained, and strength manifestation at low temperature is easily obtained.

In the rapid hardening material of the present embodiment, the surface area of the rapid hardening material is preferably adjusted to 3000 to 9000cm by grinding ² Preferably 4000 to 8000cm ² And/g. By making the powder degree of the rapid hardening material 3000-9000 cm ² And/g, sufficient overspeed hardening properties can be easily obtained, and strength manifestation at low temperature can be easily obtained.

The content of the rapid hardening material is preferably 10 to 35 parts, more preferably 15 to 30 parts, and even more preferably 20 to 25 parts, based on 100 parts of the total of the cement and the rapid hardening material. When the amount is 10 to 35 parts, good initial strength properties can be easily obtained, and the decrease in long-term strength is less likely to occur.

It should be noted that rapid hardening materials and cements may also be used as the ultrarapid hardening cement. As the overspeed hard cement, a cement containing calcium fluoroaluminate (C ₁₁ A ₇ ·CaF ₂ ) Calcium sulfoaluminate (3CaO.3Al) ₂ O ₃ ·CaSO ₄ ) Cement containing the compound as a main component.

The gypsum-based material used in the present embodiment may be any of anhydrous gypsum, semi-hydrated gypsum, and dihydrate gypsum. Furthermore, chemical gypsum such as natural gypsum, phosphoric acid by-product gypsum, flue gas desulfurization gypsum, hydrofluoric acid by-product gypsum, or gypsum obtained by heat treatment of these may be used. Wherein the method comprises the steps ofFrom the viewpoint of strength expression, anhydrite and/or hemihydrate gypsum is preferable, but from the viewpoint of cost, anhydrite is preferably selected, and type II anhydrite and/or natural anhydrite is preferable. The particle size of the gypsum is preferably 3000cm in terms of Bohler's number ² Preferably 4000 to 7000cm per gram ² And/g. Through 3000cm ² And/g or more, the initial strength manifestation can be well exhibited.

The amount of gypsum to be used is preferably 10 to 200 parts, more preferably 15 to 150 parts, and even more preferably 20 to 130 parts, based on 100 parts of the calcium aluminate compound. By setting the range to this value, the strength-exhibiting property can be exhibited satisfactorily.

(Cement)

The "cement" in this embodiment is not particularly limited, and examples thereof include various portland cements of ordinary, early strength, medium heat and low heat prescribed in Japanese Industrial Standards (JIS), various mixed cements mixed with blast furnace slag, fly ash and silica, filled cements mixed with limestone powder, fine blast furnace slag powder and the like, and all cements such as environment-friendly cement (environment-friendly cement) produced from municipal waste incineration ash and sewage sludge incineration ash as raw materials. In addition, cement specified in foreign EN197-2000 and all cement specified in the Chinese GB standard can be cited, and one or more of them can be used.

The constituent compounds of portland cement are further mixed with tricalcium silicate (3 cao—sio) ₂ ) Dicalcium silicate (2cao.sio) ₂ ) Aluminate (3 CaO. Al) ₂ O ₃ ) Ferrite (4 CaO. Al) ₂ O ₃ ·Fe ₂ O ₃ ) And dihydrate gypsum (sometimes a part of which is changed to hemihydrate gypsum). In the present embodiment, from the viewpoint of strength expression, it is preferable to select cement that does not contain a mixed material such as blast furnace slag, fly ash, silica, or limestone fine powder, and among these, cement having a high tricalcium silicate content and a high powder content (fine particle size) is preferable. As the cement corresponding thereto, for example, when exemplified in cement in japan, early strength cement and ordinary cement can be cited. In addition, if in ChinaExamples of the cement include p·ii 52.5 and p·ii 42.5.

In the present embodiment, in addition to the rapid hardening material, the dormancy agent, and the aluminum sulfate-based hardening accelerator described above, one or more of an expansive material, a water reducing agent, an AE water reducing agent, a high performance water reducing agent, slag such as fine powder of blast furnace slag, a limestone powder, a mixed material such as fly ash and silica powder, a defoaming agent, a thickener, an antirust agent, an antifreezing agent, a shrinkage reducing agent, a clay mineral such as a polymer and bentonite, and an anion exchanger such as hydrotalcite may be used in the material a and/or the material B within a range that does not substantially hinder the object of the present invention.

[2] Ready-mixed factory-leaving type rapid hardening concrete composition

The ready-mixed factory-like rapid hardening concrete composition of the present embodiment is obtained by mixing a material a containing cement, rapid hardening material and a dormancy agent with a material B containing an aluminum sulfate-based hardening accelerator (which contains aluminum sulfate). The stoichiometric ratio of the dormancy agent represented by the above formula (1) to aluminum sulfate is 0.5 to 5. The preferable range and the like are the same as those mentioned in the "ready-mixed factory-like rapid hardening concrete material of component type".

In a ready-mix plant, it is necessary to prepare various kinds of base concrete mixed with a material a, and a material B is required to add and mix the various kinds of base concrete after being transported to a site. If the B materials are mixed in advance with various base concretes not at a construction site but at a ready-mix factory, the usable time cannot be ensured. In addition, when both the rapid hardening material and the B material are added to the ready-mixed site, the usable time becomes extremely short, and the concrete has to be discarded during transportation.

When the material B is added to a ready-mixed site and the rapid hardening material is added to a construction site, the usable time after the addition of the rapid hardening material is 10 minutes or less, and the construction becomes extremely short. When the rapid hardening material and the material B are added to the construction site, the usable time is shortened, the compressive strength is also low, and only about 30% of the drum volume of the stirrer can be transported. Thus, the timing of adding the material a and the material B is extremely important.

In the present embodiment, therefore, the ready-mixed factory-like rapid hardening concrete composition of the present embodiment can be produced by preparing a two-component type of a material and a material B, specifically, by transporting the base concrete in which the material a is mixed in the ready-mixed factory to the construction site and mixing the material B in the construction site.

[ preparation method of ready-mixed factory-like quick-hardening concrete ]

An embodiment of the method for producing ready-mixed factory-like rapid hardening concrete according to the present invention includes, in order, at least a step of kneading a material a together with kneading water in a kneading vessel to prepare a base concrete (kneading step), and a step of further mixing a material B at, for example, a construction site.

The kneading water is supplied from, for example, a pre-mixing site, a pre-mixing plant, or the like. In addition, in the kneading step, the kneading is carried out while the conveying is often carried out.

In the kneading step, the volume of the base concrete containing at least the material a and the kneading water is preferably 40% (volume%) or more, more preferably 50% or more, of the internal volume of the kneading (and transporting) vessel.

Here, the kneading (and transporting) vessel means a vessel which is attached to a premixed material transporting vehicle such as a drum of a mixer truck and can hold a premixed material while stirring the premixed material.

The type of the B material and the above-described stoichiometric ratio are preferably determined within an appropriate range so that the usable time after mixing the B material can be ensured to be 10 minutes or longer, preferably 15 minutes or longer.

As described above, the two-component ready-mix factory-type rapid hardening concrete material according to the present embodiment is suitable for use as a material to be added after a casting operation by mixing a ready-mix material (ready-mix concrete) and then transporting the mixed material to a construction site and leaving the factory. The usable time may be, for example, 120 minutes or longer, and preferably 180 minutes or longer.

Examples

The present invention will be described in more detail with reference to examples, but the present invention is not limited thereto.

Experimental example 1

Preparation of Cement 375kg/m ³ Quick hardening material A125 kg/m ³ The water/binding material ratio was 32%, s/a=42%, air quantity was 2.0±1.5% by volume of fast hardening concrete. At this time, 1.5 parts of dormancy agent 1 was added to 100 parts of a bonding material composed of cement and a rapid hardening material so as not to be hardened by hydration (material A) for 24 hours or more. It is assumed that the transportation time to the site and the waiting time after reaching the construction site were generated, and after 120 minutes, the B material containing the hardening accelerator was added at the stoichiometric ratio shown in table 1 below. The pot life after the addition of the B material was measured, and the compressive strength after 6 hours after the addition of the B material (after 8 hours after completion of kneading) was measured. S/a is the fine aggregate ratio, and is a value representing the absolute volume ratio of the amount of fine aggregate to the total amount of aggregate in the concrete in percent. The ambient temperature was set at 20 ℃. The stoichiometric ratio is calculated from the above-described formula (1).

< materials used >

(1) Hardening accelerator I, II

Hardening accelerator I: liquid aluminum sulfate with 27% aluminum sulfate (used in experiment No. 1-2-1-6) and water as solvent

Hardening accelerator II: powdered aluminum sulfate (14 Water salt), a material passing through a 0.6mm sieve was used (used in experiment Nos. 1-7)

(2) Quick hardening material

Fast hardening material a: caO-Al ₂ O ₃ -SiO ₂ Is an equal amount of mixture of amorphous material and anhydrous gypsum. CaO-Al ₂ O ₃ -SiO ₂ CaO of amorphous material is 43% and Al ₂ O ₃ 44% of SiO ₂ 10% and 3% others. Density 2.85g/cm ³ Specific surface area of Bosch 5000cm ² G, degree of amorphism 90%

(3) Dormancy agent

Dormancy agent 1: mixture of 75 parts of reagent grade 1 potassium carbonate and 25 parts of reagent grade 1 citric acid

(4) Others

And (3) cement: commercially available Portland Cement (Denka Co., ltd., density 3.15 g/cm) ³ )

Anhydrous gypsum: type II anhydrite, pH3.0, bo's specific surface area 5000cm ² /g

Water: tap water

Fine aggregate: natural river sand

Coarse aggregate: broken stone

< measurement method >

Usable time: the start time of coagulation was measured as a usable time according to JIS A1147.

Compressive strength: measured according to JIS A1108.

TABLE 1

Experimental example 2

The procedure of example 1 was repeated except that CaO and MgO (both as reagents) were dissolved in the hardening accelerator I so that the contents of the hardening accelerators I were set to the contents shown in Table 2 below with respect to 100 parts of aluminum sulfate, and the hardening accelerators I-1 to I-4 were prepared and used instead of the hardening accelerator I. The results are shown in Table 2.

TABLE 2

Experimental example 3

The procedure of example 1 was repeated except that the type and the stoichiometry of the dormancy agent were changed as shown in Table 3 using the material B used in experiment Nos. 1 to 4. The results are shown in Table 3. In the case of using the non-dormancy agent 2, the non-dormancy agent 2 was 112 parts per 100 parts of aluminum sulfate.

< materials used >

Dormancy agent 1: mixture of 75 parts of reagent 1 grade potassium carbonate and 25 parts of reagent 1 grade citric acid non-dormancy agent 2: reagent grade 1 potassium carbonate

Dormancy agent 3: reagent grade 1 citric acid

Dormancy agent 4: reagent 1 grade tartaric acid (C) ₄ H ₆ O ₆ M.w. = 150.09,2 valent base

TABLE 3

As is clear from table 3, the effect of the present invention is particularly well exhibited when hydroxycarboxylic acid or a mixture of hydroxycarboxylic acid and alkali metal carbonate other than lithium is used as the dormancy agent.

Experimental example 4

The procedure of example 1 was repeated except that the type of cement and the amount of the dormancy agent 1 used in the materials A used in the experiments No.1 to 4 were changed as shown in the following Table 4. The results are shown in table 4 below.

TABLE 4

As is clear from Table 4, in any cement, by properly controlling the amount of the dormancy agent, a certain usable time was obtained, and a good 6-hour strength and a good 1-day strength were obtained.

Experimental example 5

The procedure of example 1 was repeated except that the type and amount of the rapid hardening material used in the materials A used in the experiments No.1 to 4 were changed as shown in Table 5 below. The results are shown in table 5 below. The rapid hardening materials B to D are as follows.

< materials used >

Fast hardening material B: caO-Al ₂ O ₃ -SiO ₂ Is an equal amount of mixture of amorphous material and anhydrous gypsum. CaO-Al ₂ O ₃ -SiO ₂ CaO of amorphous material is 47% and Al ₂ O ₃ 47% of SiO ₂ 3% and the other 3%. Density 2.85g/cm ³ Specific surface area of Bosch 5000cm ² G, degree of amorphism 90%

Fast hardening material C: with CaO.Al ₂ O ₃ Equal amount of mixture of high alumina cement No.1 and anhydrous gypsum as main components. Density 3.00g/cm ³ Specific surface area of Bosch 5000cm ² /g

Fast hardening material D: contains 3CaO.3Al ₂ O ₃ ·CaSO ₄ Overspeed hard cement with a compound of the group as a main component (40%). Density 2.80g/cm ³ Specific surface area of Bosch 5000cm ² /g

TABLE 5

As is clear from table 5, the cured product was not cured for 24 hours or more without adding a rapid hardening material, and the cured product was not excellent in 6-hour strength and 1-day strength, but the cured product was excellent in 6-hour strength and 1-day strength after a predetermined usable time was obtained by adding a rapid hardening material. Further, it was found that the abrasion resistance was also excellent. Further, it is found that the effects of the present invention can be exerted even if the kind of the rapid hardening material is changed.

Experimental example 6

The procedure of example 1 was repeated except that the addition timings (locations) of the materials A and B in the experiments No.1 to 4 were changed as shown in Table 6 below. The results are shown in Table 6 below.

TABLE 6

*1: the 120-minute usable time cannot be ensured, and the product cannot be transported to the site and discarded during the process.

*2: the available time after arriving at the site is insufficient, and the construction is impossible.

*3: the term "after arrival of the pot life" in the table refers to the pot life from the addition of the hard start agent and/or the fast hardening material.

As is clear from table 6, when the material a was added in the ready-mix factory and the material B was not added at the site of the work, the effect of the present invention was not obtained. When both the material a and the material B are added to the ready-mixed site, the usable time is 60 minutes, and the usable time becomes extremely short, and the material a and the material B have to be discarded during transportation. In addition, when the material B is added to the ready-mixed site and the material a is added to the construction site, the usable time after the addition is 10 minutes, which is extremely short and cannot be constructed. It is found that when the materials a and B are added at the site of construction, the time required for use is shortened and the compressive strength is low, and in addition, only about 30% of the drum volume of the mixer serving as a kneading and transporting container can be transported.

Industrial applicability

The ready-mixed factory-like rapid hardening concrete composition of the present invention ensures a sufficient usable time and is excellent in initial strength performance, and is therefore particularly suitable for use in the civil engineering and construction field.

Claims

1. A two-component ready-mixed factory-like rapid hardening concrete material comprising a material A and a material B, wherein the material A comprises cement, a rapid hardening material and a dormancy agent, the material B comprises an aluminum sulfate-based hardening accelerator, the aluminum sulfate-based hardening accelerator comprises aluminum sulfate, and the stoichiometric ratio of the dormancy agent represented by the following formula (1) to the aluminum sulfate is 0.5-5;

2. The two-component ready-mixed factory-type quick-setting concrete material according to claim 1, wherein the aluminum sulfate-based hardening accelerator further contains magnesium and calcium in an amount of 0.007 to 4 parts by mass in terms of oxide based on 100 parts by mass of the aluminum sulfate.

3. A ready-mixed factory-like rapid hardening concrete composition comprising a material a containing cement, a rapid hardening material and a dormancy agent, and a material B containing an aluminum sulfate-based hardening accelerator, wherein the aluminum sulfate-based hardening accelerator contains aluminum sulfate, and wherein the stoichiometric ratio of the dormancy agent represented by the following formula (1) to the aluminum sulfate is 0.5 to 5;