Method for evaluating filling property of cement milk and method for producing cement milk

Abstract

To provide a filling property evaluation method of cement milk capable of evaluating the presence or absence of material separation and accurately evaluating the filling property to open graded asphalt pavement, and a manufacturing method of cement milk using the filling property evaluation method of cement milk.SOLUTION: In a filling property evaluation method of cement milk, the filling property of cement milk containing at least one kind selected from a group consisting of limestone powder, fly ash, and blast furnace slag fine powder, cement, and water is evaluated based on a filling property index F calculated from the following formula (I). F = λ / σ (I) Here, in the formula (I), λ is a variable represented by the following formula (II), and σ is a material constant. Λ = T3 / (P1 / 3) (II) Here, in the formula (II), T is a table flow value, and P is a P funnel flow time.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a method for evaluating the filling property of cement milk and a method for producing cement milk. [Background technology]

[0002] Semi-flexible pavement is a paving method in which cement milk is filled into an open-graded asphalt pavement with a void ratio of 20 to 25%, and is known as a pavement with excellent durability, combining the high flexibility of asphalt pavement with the high rigidity of concrete pavement.Such semi-flexible pavements are not only used in areas such as before intersections on heavy traffic roads, roundabouts in front of train stations, bus stops, and parking lots in service areas, but in recent years have also become widely used in the outer ditches of factories and warehouses, and as pavements for port facilities.

[0003] Semi-flexible pavements are required to be able to reliably fill with cement milk. For example, Non-Patent Document 1 discloses methods for evaluating the filling property of cement milk, which include pouring cement milk into a P funnel and evaluating the time it takes for the cement milk to flow down from the outlet of the P funnel (hereinafter referred to as P funnel flow time), and filling a cylindrical cone with cement milk that is 50 mm in inner diameter and 100 mm in height and evaluating the degree to which the cement milk spreads when the cylindrical cone is pulled up (hereinafter referred to as table flow value). [Prior art documents] [Non-patent literature]

[0004] [Non-Patent Document 1] Study on the filling property of cement milk used for semi-flexible pavement, Proceedings of the Japan Concrete Institute, No.1, Vol.39, pp.1279-1284, 2017 (Shimizu Susumu, Fujiwara Hiromi, Maruoka Masatomo) Summary of the Invention [Problem to be solved by the invention]

[0005] In general semi-flexible pavements, the standard value for the filling property of cement milk is sometimes required to be a P funnel flow time of 10 to 14 seconds. However, even if the P funnel flow time does not meet the standard value, the filling property of cement milk into open-graded asphalt pavement may be good, and it is difficult to say that the evaluation method based on the P funnel flow time can fully grasp the filling property of cement milk.

[0006] Furthermore, Non-Patent Document 1 describes that the filling property of cement milk can be evaluated by the table flow value. However, when the table flow value becomes large, material separation of the cement milk may occur, and the evaluation method using the table flow value is not sufficient as a method for evaluating the filling property of cement milk because it is not possible to grasp the criteria for the occurrence of this material separation.

[0007] The present invention has been made in consideration of the above circumstances, and aims to provide a method for evaluating the filling property of cement milk that can evaluate the presence or absence of material separation and can more accurately evaluate the filling property into open-graded asphalt pavement, and a method for manufacturing cement milk using the method for evaluating the filling property of cement milk. [Means for solving the problem]

[0008] The method for evaluating the filling property of cement milk according to the present invention evaluates the filling property of cement milk containing at least one selected from the group consisting of limestone powder, fly ash, and ground granulated blast furnace slag, cement, and water, based on a filling property index F calculated from the following formula (I).

[0009]

number

[0010] Here, in formula (I), λ is a variable expressed by the following formula (II), and σ is a material constant.

[0011]

number

[0012] In the formula (II), T is the table flow value, and P is the P funnel flow time.

[0013] The method for evaluating the filling property of cement milk according to the present invention can evaluate the presence or absence of material separation by using the filling property index F calculated from the above formula (I), and can more accurately evaluate the filling property into open-graded asphalt pavement.

[0014] The method for producing cement milk according to the present invention is a method for producing cement milk containing at least one selected from the group consisting of limestone powder, fly ash, and ground granulated blast furnace slag, cement, and water, and includes an adjustment step of adjusting the amounts of the at least one selected from the group consisting of limestone powder, fly ash, and ground granulated blast furnace slag, cement, and water so that the filling index F calculated from the following formula (I) is 22 or more and 44 or less.

[0015]

number

[0016] Here, in formula (I), λ is a variable expressed by the following formula (II), and σ is a material constant.

[0017]

number

[0018] In the formula (II), T is the table flow value, and P is the P funnel flow time.

[0019] The inventors have found that cement milk having a filling index F of 22 or more and 44 or less has excellent filling properties and reduces material separation. Therefore, the method for producing cement milk according to the present invention makes it possible to produce cement milk that has excellent filling properties into open-graded asphalt pavement and is less likely to cause material separation, by adjusting the blending amounts of each component so that the filling index F calculated from the above formula (I) is 22 or more and 44 or less.

[0020] In the method for producing cement milk according to the present invention, the limestone powder may be at least one of natural limestone powder and artificial limestone powder.

[0021] According to the configuration of the method for producing cement milk of the present invention, the cement milk can be used as a cement extender, thereby reducing the amount of cement used, which emits large amounts of carbon dioxide during production, and thereby reducing the environmental burden caused by the production of cement milk.

[0022] In the method for producing cement milk according to the present invention, the amount of the cement mixed may be 25% by mass or more and 50% by mass or less with respect to the total amount of cement milk.

[0023] According to the method for producing cement milk of the present invention, the strength of the cement milk can be sufficiently ensured.

[0024] In the method for producing cement milk according to the present invention, the cement may be high-early-strength Portland cement.

[0025] According to the method for producing cement milk of the present invention, with such a configuration, it is possible to produce cement milk that is excellent in fluidity and strength development.

[0026] In the method for producing cement milk of the present invention, the cement milk may further contain a fluidity adjuster, and in the adjustment step, the amounts of at least one selected from the group consisting of the limestone powder, the fly ash, and the blast furnace slag ground powder, the cement, the water, and the fluidity adjuster may be adjusted.

[0027] According to the above-described configuration, the method for producing cement milk of the present invention can produce cement milk that has improved fillability into open-graded asphalt pavement by ensuring sufficient strength of the cement milk.

[0028] In the method for producing cement milk of the present invention, the fluidity adjuster may be at least one selected from the group consisting of polycarboxylic acid ether-based water reducers, naphthalene sulfonic acid-based water reducers, and melamine sulfonate-based water reducers.

[0029] According to the method for producing cement milk of the present invention, as configured above, it is possible to produce cement milk that has improved fillability into open-graded asphalt pavement.

[0030] In the method for producing cement milk according to the present invention, the amount of the fluidity modifier to be mixed may be 0.1% by mass or more and 2.0% by mass or less with respect to the cement.

[0031] According to the method for producing cement milk of the present invention, as configured above, it is possible to produce cement milk that has improved fillability into open-graded asphalt pavement. [Effects of the Invention]

[0032] According to the present invention, it is possible to provide a method for evaluating the filling property of cement milk, which can evaluate the presence or absence of material separation and can more accurately evaluate the filling property into open-graded asphalt pavement, and a method for manufacturing cement milk using the method for evaluating the filling property of cement milk. DETAILED DESCRIPTION OF THE INVENTION

[0033] The method for evaluating the filling property of cement milk and the method for producing cement milk according to this embodiment will be described below.

[0034] <Method for evaluating the filling properties of cement milk> The method for evaluating the filling property of cement milk according to this embodiment evaluates the filling property of cement milk containing at least one selected from the group consisting of limestone powder, fly ash, and blast furnace slag ground powder, cement, and water, based on the filling property index F calculated from the following formula (I).

[0035]

number

[0036] Here, in formula (I), λ is a variable expressed by the following formula (II), and σ is a material constant.

[0037]

number

[0038] The P funnel flow time can be measured based on the method described in the "Pavement Survey and Test Methods Handbook C041."

[0039] The table flow value can be measured in accordance with the method described in "JASS 15 M-103."

[0040] The material constant σ means a value equivalent to the length of the solid content contained in cement milk per unit length (a value equivalent to the length when the particles of cement, limestone powder, fly ash, and blast furnace slag powder are lined up in 1 cm), calculated using the following formula (III) from the blending amounts, surface areas, and densities of cement, limestone powder, fly ash, and blast furnace slag powder. Note that the value equivalent to the length is calculated when the unit of the material constant is cm. 3 / 2 / cm, it can be said to be a value between the concepts of length and area.

[0041]

number

[0042] In the formula (III), C is the amount of cement mixed (mass%), and Cb is the specific surface area of ​​the cement (cm 2 / g) and Cd is the cement density (g / cm 3 ), N is the blending amount of natural limestone powder (mass%), and Nb is the specific surface area of ​​the natural limestone powder (cm 2 / g), and Nd is the density of natural limestone powder (g / cm 3 ), A is the blending amount of artificial limestone powder (mass%), and Ab is the specific surface area of ​​the artificial limestone powder (cm 2 / g), and Ad is the density of the artificial limestone powder (g / cm 3 ), FA is the fly ash content (mass%), and Fb is the specific surface area of ​​the fly ash (cm 2 / g), and Fd is the density of the fly ash (g / cm 3 ), B is the blending amount of ground granulated blast furnace slag (mass%), and Bb is the specific surface area of ​​the ground granulated blast furnace slag (cm 2 / g), and Bd is the density of ground granulated blast furnace slag (g / cm 3 )

[0043] Examples of cement that can be used include Portland cements such as ordinary Portland cement, high-early-strength Portland cement, ultra-high-early-strength Portland cement, moderate-heat Portland cement, sulfate-resistant Portland cement, and white Portland cement, as defined in JIS R 5210:2019; mixed cements such as blast-furnace cement, fly ash cement, and silica cement; ultra-rapid-hardening cement, and alumina cement. One type of cement may be used alone, or two or more types may be used in combination.

[0044] The specific surface area of ​​the cement is not particularly limited, and may be, for example, 4000 cm2 / g or more 5000cm 2 / g or less, or 4200 cm 2 / g or more 4800cm 2 The specific surface area of ​​the cement can be measured based on the method described in JIS R 5201:2015 "Physical testing methods for cement, 8. Fineness test, 8.1 Specific surface area test."

[0045] The density of the cement is not particularly limited, and may be, for example, 3.06 g / cm 3 More than 3.12g / cm 3 It may be less than 3.08 g / cm 3 More than 3.10g / cm 3 The specific surface area of ​​the cement can be measured based on the method described in JIS R 5201:2015 "Physical testing methods for cement, 7. Density test."

[0046] When the cement is normal Portland cement, high-early-strength Portland cement, or ultra-high-early-strength Portland cement, the cement contains natural limestone powder, ground granulated blast furnace slag, and / or fly ash as minor mixed components. In this case, the blending amount, specific surface area, and density of the cement include the values ​​of the natural limestone powder, ground granulated blast furnace slag, and fly ash as minor mixed components.

[0047] When the cement is blast furnace cement or fly ash cement, the cement contains ground granulated blast furnace slag or fly ash as an admixture. In this case, the blending amount, specific surface area, and density of the cement are values ​​including the ground granulated blast furnace slag or fly ash as an admixture.

[0048] Examples of limestone powder include natural limestone powder and artificial limestone powder.

[0049] As the natural limestone powder, for example, one having a calcium carbonate content of 95% by mass or more can be used.

[0050] The specific surface area of ​​the natural limestone powder is not particularly limited, and may be, for example, 3000 cm 2 / g or more 15000cm 2 / g or less, or 3500 cm 2 / g or more 12000cm 2 The specific surface area of ​​the natural limestone powder can be measured in the same manner as the specific surface area of ​​the cement.

[0051] The density of the natural limestone powder is not particularly limited, and may be, for example, 2.60 g / cm 3 More than 2.80g / cm 3 The density of the natural limestone powder can be measured in the same manner as the density of the cement.

[0052] The artificial limestone powder is not particularly limited, and examples thereof include those derived from calcium-containing waste, those obtained by synthesis, etc. Note that the artificial limestone powder may have a calcium carbonate content of 90% by mass or more.

[0053] Examples of calcium-containing waste include waste gypsum boards and sludge solids.

[0054] Examples of calcium obtained by synthesis include calcium obtained by reacting the calcium-containing waste with carbon dioxide emitted from a factory or the like; calcium hydroxide obtained by adding water to calcium oxide obtained by calcining natural calcium carbonate, and calcium hydroxide obtained by reacting carbon dioxide generated when calcining natural calcium carbonate.

[0055] The specific surface area of ​​the artificial limestone powder is not particularly limited, and may be, for example, 5000 cm 2 / g or more 9000cm 2 The specific surface area of ​​the artificial limestone powder can be measured in the same manner as the specific surface area of ​​the cement.

[0056] The density of the artificial limestone powder is not particularly limited, and may be, for example, 2.55 g / cm 3 More than 2.75g / cm 3 The density of the artificial limestone powder can be measured in the same manner as the density of the cement.

[0057] The fly ash is not particularly limited as long as it complies with JIS A 6201:2024 "Fly ash for concrete," and any fly ash known as a cement admixture can be used.

[0058] The specific surface area of ​​the fly ash is not particularly limited, and may be, for example, 2500 cm 2 / g or more 5000cm 2 The specific surface area of ​​the fly ash can be measured in the same manner as the specific surface area of ​​the cement.

[0059] The density of the fly ash is not particularly limited, and may be, for example, 1.95 g / cm 3 The density of the fly ash can be measured in the same manner as the density of the cement.

[0060] The ground granulated blast furnace slag is not particularly limited as long as it complies with JIS A 6206:2024 "Ground granulated blast furnace slag for concrete," and any ground granulated blast furnace slag known as a cement admixture can be used. The ground granulated blast furnace slag is mainly classified into air-cooled ground granulated blast furnace slag, which becomes crystalline when slowly cooled from a molten state and solidifies into a rock-like substance, and granulated blast furnace slag, which becomes sandy and amorphous when rapidly cooled from a molten state with water. The ground granulated blast furnace slag may be air-cooled ground granulated blast furnace slag or granulated blast furnace slag.

[0061] The specific surface area of ​​the ground granulated blast furnace slag is not particularly limited, and may be, for example, 2750 cm 2 / g or more, and 2 / g or more, and 2 / g or more, and 2 The Blaine specific surface area of ​​the ground granulated blast furnace slag may be, for example, 10,000 cm 2 / g or less than 7000 cm 2 / g or less than 5000 cm 2 / g or less than 3500 cm 2 The specific surface area of ​​the ground granulated blast furnace slag can be measured in the same manner as the specific surface area of ​​the cement.

[0062] The density of the ground granulated blast furnace slag is not particularly limited, and may be, for example, 2.80 g / cm 3 The density of the ground granulated blast furnace slag can be measured in the same manner as the density of the cement.

[0063] The water is not particularly limited, and examples thereof include tap water, industrial water, recycled water, groundwater, river water, and rainwater. The water preferably does not contain organic matter, chloride ions, sodium ions, potassium ions, and the like, which have adverse effects on the hydration reaction of cement and concrete, or contains only trace amounts of such ions. The water is more preferably tap water or industrial water of stable quality.

[0064] The cement milk may contain admixtures. Examples of admixtures include fluidity adjusters (e.g., air-entraining water-reducing agents, high-performance water-reducing agents, high-performance air-entraining water-reducing agents, superplasticizers, etc.), air-entraining agents, separation-reducing agents, setting retarders (e.g., tartaric acid, etc.), setting accelerators (e.g., aluminum sulfate, etc.), quick-setting admixtures, shrinkage-reducing agents, foaming agents, foaming agents, waterproofing agents, etc. Note that one type of admixture may be used alone, or two or more types may be used in combination.

[0065] The cement milk may also contain an admixture. Examples of the admixture include inorganic fine powders such as silica fume, cement kiln dust, blast furnace fume, ground converter slag, hemihydrate gypsum, expanding agents, ground quicklime, and ground dolomite, as well as inorganic fillers such as sodium bentonite, calcium bentonite, attapulgite, sepiolite, activated clay, acid clay, allophane, imogolite, shirasu (volcanic ash), shirasu balloons, kaolinite, metakaolin (calcined clay), synthetic zeolite, artificial zeolite, mordenite, and clinoptilolite. One type of admixture may be used alone, or two or more types may be used in combination.

[0066] The cement milk may also contain fine aggregate. Fine aggregate refers to aggregate that passes entirely through a 10 mm mesh sieve and 85% or more by mass passes through a 5 mm mesh sieve (JIS A 0203:2019). Examples of fine aggregate include river sand, sea sand, land sand, crushed sand, and silica sand. Of these, silica sand is preferred as the fine aggregate. One type of fine aggregate may be used alone, or two or more types may be used in combination.

[0067] The method for evaluating the filling property of cement milk according to this embodiment evaluates the filling property of cement milk containing at least one selected from the group consisting of limestone powder, fly ash, and blast furnace slag powder, cement, and water based on the filling property index F calculated from the above formula (I), thereby making it possible to evaluate the presence or absence of material separation and to more accurately evaluate the filling property into open-graded asphalt pavement.

[0068] <Cement milk manufacturing method> The method for producing cement milk according to this embodiment is a method for producing cement milk containing at least one selected from the group consisting of limestone powder, fly ash, and ground granulated blast furnace slag, cement, and water, and includes an adjustment step for adjusting the amounts of the at least one selected from the group consisting of limestone powder, fly ash, and ground granulated blast furnace slag, cement, and water.

[0069] In the adjusting step, the blending amounts of the at least one selected from the group consisting of the limestone powder, the fly ash, and the ground granulated blast furnace slag, the cement, and the water are adjusted so that the fillability index F calculated from the following formula (I) is 22 or more and 44 or less.

[0070]

number

[0071] Here, in formula (I), λ is a variable expressed by the following formula (II), and σ is a material constant.

[0072]

number

[0073] In the formula (II), T is the table flow value, and P is the P funnel flow time.

[0074] The fillability index F can be increased by, for example, increasing the amount of water blended, increasing the amount of a flowability modifier or the like blended, and can be decreased by decreasing the amount of water blended, decreasing the amount of a flowability modifier or the like blended, adding a thickener or the like, or the like.

[0075] In the method for producing cement milk according to this embodiment, from the viewpoint of improving the fillability into open-graded asphalt pavement by ensuring sufficient strength of the cement milk, in a preferred embodiment, the cement milk further contains a fluidity adjuster, and in the adjustment process, the amounts of at least one selected from the group consisting of the limestone powder, the fly ash, and the blast furnace slag ground powder, the cement, the water, and the fluidity adjuster are adjusted.

[0076] The adjusting step can include, for example, a first step of mixing the cement with at least one selected from the group consisting of the limestone powder, the fly ash, and the ground granulated blast furnace slag, adding water while kneading, and further kneading to obtain a cement composition, and a second step of adding the fluidity adjuster to the cement composition as a premix.

[0077] The table flow value, P funnel flow time, and material constants can be calculated in the same manner as in the method for evaluating the filling property of cement milk according to the present embodiment.

[0078] Examples of the flowability adjuster include water-reducing agents and fluidizing agents such as AE water-reducing agents, high-performance water-reducing agents, and high-performance AE water-reducing agents. Among these, the flowability adjuster is preferably a water-reducing agent.

[0079] Specifically, examples of the fluidity modifier include polycarboxylic acid ether-based water reducing agents, naphthalenesulfonic acid-based water reducing agents, melamine sulfonate-based water reducing agents, oxycarboxylic acid-based water reducing agents, ligninsulfonic acid-based water reducing agents, aminosulfonic acid-based water reducing agents, polyol complexes, etc. Among these, from the viewpoint of producing cement milk with improved fillability into open-graded asphalt pavement, the fluidity modifier is preferably at least one selected from the group consisting of polycarboxylic acid ether-based water reducing agents, naphthalenesulfonic acid-based water reducing agents, and melamine sulfonate-based water reducing agents.

[0080] The amount of flowability adjuster to be added is preferably 0.1% by mass or more and 2.0% by mass or less, and more preferably 0.5% by mass or more and 1.5% by mass or less, relative to the cement, from the viewpoint of producing cement milk with improved fillability into open-graded asphalt pavement.

[0081] The cement, the limestone powder, the fly ash, the ground granulated blast furnace slag, and the water may be the same as those used in the method for evaluating the fillability of cement milk according to the present embodiment. The limestone powder, the fly ash, and the ground granulated blast furnace slag can be used as cement extenders.

[0082] From the viewpoint of producing cement milk having excellent fluidity and strength development, the cement is preferably ordinary Portland cement or high-early-strength Portland cement, and more preferably high-early-strength Portland cement.

[0083] From the viewpoint of ensuring sufficient strength of the cement milk, the amount of the cement mixed is preferably 25% by mass or more and 50% by mass or less, more preferably 27% by mass or more and 47% by mass or less, based on the total cement milk. When two or more types of cement are contained, the amount mixed is the total amount of cement mixed.

[0084] The limestone powder is preferably at least one of natural limestone powder and artificial limestone powder, from the viewpoint of reducing the amount of cement used, which emits a large amount of carbon dioxide during production, thereby reducing the environmental load caused by the production of cement milk.

[0085] The amount of natural limestone powder to be blended is preferably 10% by mass or more and 45% by mass or less, and more preferably 12% by mass or more and 40% by mass or less, of the total cement milk, from the perspective that by using it as a cement extender, the amount of cement used, which emits large amounts of carbon dioxide during production, is reduced, thereby reducing the environmental burden caused by the production of cement milk.

[0086] The amount of the artificial limestone powder mixed is preferably 10% by mass or more and 45% by mass or less, and more preferably 12% by mass or more and 40% by mass or less, based on the total cement milk, from the viewpoint of reducing carbon dioxide emissions in the production of cement milk by using it as a cement extender.

[0087] The amount of fly ash to be blended is preferably 10% by mass or more and 45% by mass or less, and more preferably 12% by mass or more and 40% by mass or less, relative to the total cement milk, from the viewpoint of reducing the amount of cement used, which emits a large amount of carbon dioxide during production, thereby reducing the environmental impact caused by the production of cement milk.

[0088] From the viewpoint of reducing carbon dioxide emissions in the production of cement milk, the amount of the blast furnace slag powder to be mixed is preferably 10% by mass or more and 45% by mass or less, and more preferably 12% by mass or more and 40% by mass or less, relative to the total cement milk.

[0089] From the viewpoint of ensuring sufficient strength of the cement milk, the amount of water to be blended is preferably 25% by mass or more and 38% by mass or less, and more preferably 30% by mass or more and 35% by mass or less, based on the total cement milk.

[0090] The method for producing cement milk according to this embodiment may use the same admixtures, additives and / or fine aggregates as those used in the method for evaluating the filling property of cement milk according to this embodiment.

[0091] The admixture and / or fine aggregate can be used in the first step of the preparation step. The admixture can be used in the first step and / or the second step of the preparation step.

[0092] The particle size of the fine aggregate may be, for example, 0.1 mm or more and 0.4 mm or less. The particle size of the fine aggregate can be measured in accordance with the method described in JIS A 1102:2014.

[0093] The fine aggregate preferably passes through a 0.425 mm sieve and is retained on a 0.106 mm sieve. Examples of such fine aggregate include No. 6 silica sand (particle size: 0.2 to 0.4 mm) and No. 7 silica sand (particle size: 0.1 to 0.2 mm). Of these, the fine aggregate is preferably No. 6 silica sand.

[0094] The method for producing cement milk according to this embodiment is a method for producing cement milk containing at least one selected from the group consisting of limestone powder, fly ash, and granulated blast furnace slag, cement, and water, and includes an adjustment step for adjusting the amounts of at least one selected from the group consisting of limestone powder, fly ash, and granulated blast furnace slag, cement, and water so that the filling index F calculated from the above formula (I) is 22 or more and 44 or less. This makes it possible to produce cement milk that has excellent filling ability into open-graded asphalt pavement and is less likely to cause material separation.

[0095] Furthermore, in the method for producing cement milk according to this embodiment, at least one selected from the group consisting of limestone powder, fly ash, and ground granulated blast furnace slag can be used as a cement extender. Therefore, by reducing the amount of cement while increasing the amount of at least one selected from the group consisting of limestone powder, fly ash, and ground granulated blast furnace slag so that the filling index F is 22 or more and 44 or less, the amount of cement used, which emits a large amount of carbon dioxide during production, can be reduced, thereby reducing the environmental impact caused by the production of cement milk.

[0096] In the method for producing cement milk according to this embodiment, the limestone powder is at least one of natural limestone powder and artificial limestone powder, so that the limestone powder can be used as a cement extender. This reduces the amount of cement used, which emits a large amount of carbon dioxide during production, and reduces the environmental burden caused by the production of cement milk.

[0097] In the method for producing cement milk according to this embodiment, the amount of cement mixed is 25% by mass or more and 50% by mass or less relative to the total cement milk, thereby making it possible to ensure sufficient strength of the cement milk.

[0098] In the method for producing cement milk according to this embodiment, since the cement is high-early-strength Portland cement, it is possible to produce cement milk that is excellent in fluidity and strength development.

[0099] In the method for producing cement milk according to this embodiment, the cement milk further contains a fluidity adjuster, and in the adjustment process, by adjusting the blending amounts of at least one selected from the group consisting of the limestone powder, the fly ash, and the blast furnace slag powder, the cement, the water, and the fluidity adjuster, it is possible to produce cement milk that has improved fillability into open-graded asphalt pavement by ensuring sufficient strength of the cement milk.

[0100] In the method for producing cement milk according to this embodiment, the fluidity adjuster is at least one selected from the group consisting of polycarboxylic acid ether-based water reducers, naphthalene sulfonic acid-based water reducers, and melamine sulfonate-based water reducers, making it possible to produce cement milk with improved fillability into open-graded asphalt pavement.

[0101] The method for producing cement milk according to this embodiment makes it possible to produce cement milk with improved fillability into open-graded asphalt pavement by blending the fluidity adjuster in an amount of 0.1 mass% or more and 2.0 mass% or less relative to the cement.

[0102] The method for evaluating the filling property of cement milk and the method for manufacturing cement milk according to the present invention are not limited to the above embodiments, and various modifications are possible within the scope that does not deviate from the gist of the present invention.

[0103] The present invention includes the following aspects. [1] A method for evaluating the fillability of cement milk, which evaluates the fillability of cement milk containing at least one selected from the group consisting of limestone powder, fly ash, and blast furnace slag powder, cement, and water, based on the fillability index F calculated from the following formula (I).

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[0104] Examples of the present invention will be described below, but the present invention is not limited to the following examples.

[0105] <Preparation of cement milk> The cement milks of the test examples were prepared using the materials shown in Table 1. Specifically, first, at least one selected from the group consisting of limestone powder, fly ash, and ground granulated blast furnace slag was mixed with cement in advance in the amounts shown in Table 2, and the mixture was mixed using a hand mixer at a rotation speed of 550 rpm. The mixture was then poured into water within 30 seconds of the start of mixing, and mixed for 2 minutes to obtain cement compositions of formulations 1 to 18 (first step).

[0106] Next, the fluidity adjusters shown in Table 1 were premixed into the cement compositions of Formulations 1 to 18 obtained in the first step according to the blending amounts shown in Tables 3 and 4 (second step), to obtain the cement milk of each test example described in Tables 3 and 4. In Test Example 14, the fluidity adjuster was not premixed. For the cement milk of each test example, the P-funnel flow-down time, table flow value, and filling rate were measured according to the methods shown below, and the presence or absence of material separation was visually confirmed. Also, the filling property index F was calculated from the results of the obtained P-funnel flow-down time and table flow value. The P-funnel flow-down time, table flow value, and filling rate were measured under the environment of 20°C and 60% RH.

[0107] Incidentally, artificial limestone powder was obtained by extracting calcium ions from waste gypsum board as calcium-containing waste using bipolar membrane electrodialysis to recover carbonate containing calcium, and recombining the carbonate with carbon dioxide separated in the cement production process, and then drying and pulverizing the obtained calcium carbonate was used.

[0108] [Table 1]

[0109] [Table 2]

[0110] <P-funnel flow-down time> Based on the method described in "Pavement Survey and Test Method Handbook C041", the P-funnel flow-down time was measured for the cement milk of each test example described in Tables 3 and 4. The measurement results were evaluated based on the following criteria. The evaluation results are shown in Tables 3 and 4. ○: 10 seconds or more and 14 seconds or less ×: Less than 10 seconds or exceeding 14 seconds

[0111] The table flow value was measured for each of the cement milks of the test examples shown in Tables 3 and 4 in accordance with the method described in "JASS 15 M-103." The measurement results were evaluated based on the following indices. The results are shown in Tables 3 and 4. ○: 31.0cm or more and 38.0cm or less ×: Less than 31.0 cm or more than 38.0 cm

[0112] <Fillability index F> For the cement milk of each test example shown in Tables 3 and 4, the filling index F was calculated from the following formula (I) using the P funnel flow time and table flow value measured by the above method. The results are shown in Tables 3 and 4.

[0113]

number

[0114] Here, in formula (I), λ is a variable expressed by the following formula (II), and σ is a material constant.

[0115]

number

[0116] The material constant σ was calculated from the following formula (III) using the blending amounts, specific surface area, and density of cement, each limestone powder, fly ash, and ground granulated blast furnace slag listed in Table 1. The calculated material constant σ is shown in Table 2.

[0117]

number

[0118] In the formula (III), C is the amount of cement mixed (mass%), and Cb is the specific surface area of ​​the cement (cm 2 / g) and Cd is the cement density (g / cm 3), N is the blending amount of natural limestone powder (mass%), and Nb is the specific surface area of ​​the natural limestone powder (cm 2 / g), and Nd is the density of natural limestone powder (g / cm 3 ), A is the blending amount of artificial limestone powder (mass%), and Ab is the specific surface area of ​​the artificial limestone powder (cm 2 / g), and Ad is the density of the artificial limestone powder (g / cm 3 ), FA is the fly ash content (mass%), and Fb is the specific surface area of ​​the fly ash (cm 2 / g), and Fd is the density of the fly ash (g / cm 3 ), B is the blending amount of ground granulated blast furnace slag (mass%), and Bb is the specific surface area of ​​the ground granulated blast furnace slag (cm 2 / g), and Bd is the density of ground granulated blast furnace slag (g / cm 3 )

[0119] The measurement results were evaluated based on the following criteria. The evaluation results are shown in Tables 3 and 4. ○: 22 or more and 44 or less ×: Less than 22 or more than 44

[0120] <Filling rate> In accordance with the continuous void ratio measurement method described in the "Pavement Survey and Testing Methods Handbook B011," the specified amount of cement milk for each test example shown in Table 3 was infiltrated into an open-graded asphalt slab with a continuous void ratio of 22.0% and dimensions of 150 mm x 150 mm x 50 mm immediately after mixing. The open-graded asphalt slab was then vibrated for 10 seconds using a vibrator, and this vibration was repeated three times to smooth the surface of the open-graded asphalt slab. The mass of the smoothed open-graded asphalt slab was measured, and the filling rate was calculated from the mass of the open-graded asphalt slab before and after the cement milk infiltration. The calculated filling rate was evaluated based on the following criteria. The evaluation results are shown in Tables 3 and 4. ○: 90% or more ×: Less than 90%

[0121] <Overall rating> The following evaluations were made based on the results of the evaluation of the filling rate and the presence or absence of separation of the materials. The evaluation results are shown in Tables 3 and 4. The overall evaluation was compared with the above-mentioned filling index. ○: Filling rate was 90% or more and there was no separation of materials ×: Filling rate less than 90% or separation of materials occurred

[0122] [Table 3]

[0123] [Table 4]

[0124] As can be seen from Tables 3 and 4, the method for evaluating the filling property of cement milk according to the present invention can evaluate the presence or absence of material separation by using the filling property index F, and can more accurately evaluate the filling property into open-graded asphalt pavement.

[0125] On the other hand, the evaluation method based on the P funnel flow time may result in an "O" for the P funnel flow time but an "X" for the filling rate, or an "X" for the P funnel flow time but an "O" for the filling rate, so it is difficult to fully grasp the filling property of the cement milk. Similarly, the evaluation method based on the P funnel flow time cannot evaluate whether or not material separation occurs.

[0126] Furthermore, with the evaluation method using the table flow value, even if the evaluation result of the table flow value is "○", the evaluation result of the filling rate may be "×", or even if the evaluation result of the table flow value is "×", the evaluation result of the filling rate may be "○" even though there is no material segregation, so it is difficult to say that it is possible to fully grasp the filling properties of the cement milk or to evaluate whether or not there is material segregation.

[0127] Furthermore, the method for producing cement milk according to the present invention can produce cement milk that has excellent filling ability into open-graded asphalt pavement and is less likely to cause material separation, since the filling index F is 22 or more and 44 or less.

Claims

1. A method for evaluating the fillability of cement milk, which evaluates the fillability of cement milk containing at least one selected from the group consisting of limestone powder, fly ash, and blast furnace slag ground powder, cement, and water, based on a fillability index F calculated from the following formula (I). [Equation 1] Here, in formula (I), λ is a variable expressed by the following formula (II), and σ is a material constant. [Equation 2] In the formula (II), T is the table flow value, and P is the P funnel flow time.

2. A method for producing cement milk containing at least one selected from the group consisting of limestone powder, fly ash, and ground granulated blast furnace slag, cement, and water, A method for producing cement milk, comprising an adjusting step of adjusting the blending amounts of at least one selected from the group consisting of limestone powder, fly ash, and ground granulated blast furnace slag, cement, and water so that the filling index F calculated from the following formula (I) is 22 or more and 44 or less. [Equation 3] Here, in formula (I), λ is a variable expressed by the following formula (II), and σ is a material constant. [Equation 4] In the formula (II), T is the table flow value, and P is the P funnel flow time.

3. The method for producing cement milk according to claim 2, wherein the limestone powder is at least one of natural limestone powder and artificial limestone powder.

4. The method for producing cement milk according to claim 2 or 3, wherein the amount of cement mixed is 25% by mass or more and 50% by mass or less with respect to the total cement milk.

5. The method for producing cement milk according to claim 2 or 3, wherein the cement is early-strength Portland cement.

6. The cement milk further contains a fluidity adjuster, 4. A method for producing cement milk as described in claim 2 or 3, wherein in the adjustment step, the amounts of at least one selected from the group consisting of limestone powder, fly ash, and blast furnace slag ground powder, the cement, the water, and the fluidity adjuster are adjusted.

7. The method for producing cement milk according to claim 6, wherein the fluidity adjuster is at least one selected from the group consisting of a polycarboxylic acid ether-based water reducer, a naphthalene sulfonic acid-based water reducer, and a melamine sulfonate-based water reducer.

8. The method for producing cement milk according to claim 6, wherein the amount of the fluidity adjuster is 0.1 mass% or more and 2.0 mass% or less relative to the cement.

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