JP2008100884A - Method for designing aggregate/cement mixing ratio - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for designing an aggregate/cement mixing ratio, yielding the mixing ratio of cement to aggregate in a standardized manner, even when the particle size distribution of the aggregate significantly changes. <P>SOLUTION: In the method for designing the aggregate/cement mixing ratio, the mixing ratio of the aggregate to the cement is determined based on a standardized ratio (S/C) obtained by correcting the specific surface area of the aggregate 15 so that the thickness of cement paste 14 applied onto a surface 17 of each aggregate 15 can be assumed to be substantially constant. The standardized ratio (S/C) is calculated by multiplying the amount of cement (C<SB>1</SB>) in the actual aggregate/cement ratio (S<SB>1</SB>/C<SB>1</SB>) by a specific surface area ratio (R<SB>S</SB>), which is a ratio of an apparent first specific surface area (S<SB>W1</SB>) (m<SP>2</SP>/kg) of a previously defined standard aggregate to an apparent second specific surface area (S<SB>W2</SB>) (m<SP>2</SP>/kg) reflecting the change in the particle size distribution of the aggregate 15. The specific surface area ratio (R<SB>S</SB>) is calculated by dividing the second specific surface area (S<SB>W2</SB>) by the first specific surface area (S<SB>W1</SB>). <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an aggregate / cement mixture ratio design method for designing a mixing ratio between an aggregate amount and a cement amount of a hardened cement having a plurality of voids formed therein.

There is a hardened cement made by curing a cement mixture in which a cement paste containing a predetermined amount of water is mixed with a mixed aggregate formed from natural aggregate and medium-quality recycled aggregate (Patent Document 1). reference). The mixing ratio of the natural aggregate and the medium-quality recycled aggregate is obtained by using a predetermined calculation formula in consideration of the water absorption rate of the aggregate. The mixing ratio of cement and mixed aggregate varies depending on the material made from the cement mixture, and is designed by an appropriate method each time. As an example of the method for obtaining the mixing ratio of cement and mixed aggregate, when using the weight ratio between the weight of cement and the weight of aggregate, the volume ratio between the volume of cement and the volume of aggregate may be used. .
JP 2002-241164 A

  The mixing ratio of cement and aggregate can be determined using the weight ratio or the volume ratio when the physical properties of the aggregate are substantially constant, such as a small change in the particle size distribution of the aggregate. However, if the particle size distribution of the aggregate changes greatly, the properties during mixing of the cement and aggregate will change significantly, so the mixing ratio of cement and aggregate is designed according to the mixing conditions with the same weight ratio and the same volume ratio. It is not possible. Therefore, when the aggregate particle size distribution changes greatly, weight ratio and volume ratio cannot be used to design the mixing ratio of cement and aggregate, and the mixing ratio of cement and aggregate is uniform. I can't ask for it. The design of the mixing ratio of cement and aggregate when the particle size of the aggregate changes greatly has to rely on the designer's experience and feeling in the field.

  In addition, as an example of the property change at the time of mixing the cement and the aggregate, if the mixing ratio of the cement and the aggregate is the same and the coarse particle ratio of the aggregate is small (the fine particle content is large), the aggregate The wettability of the surface of the cement may decrease, the adhesive strength between the cement and the aggregate may be insufficient, and the compressive strength of the hardened cement may be reduced. In addition, when the mixing ratio of cement and aggregate is the same and the coarse particle ratio of the aggregate increases (the amount of fine particles is small), the wettability of the surface of the aggregate increases. When used as a panel, voids to be formed in the hardened cement material may be blocked by cement, and the sound absorption rate may be significantly reduced. One of the causes of such a phenomenon is that the surface area per unit mass of the aggregate (specific surface area) changes due to the change in the aggregate particle size distribution, and the thickness of the cement paste covering the aggregate surface. Is considered to be non-uniform.

  An object of the present invention is to provide an aggregate / cement mixture ratio design method capable of uniformly determining the mixing ratio of cement and aggregate even when the aggregate particle size distribution is greatly changed. It is in.

  The premise of the present invention to solve the above problems is made by curing a mixture of cement paste containing a predetermined amount of moisture and aggregate having a predetermined range of particle size, and a plurality of voids are formed inside. This is an aggregate / cement mixture ratio design method for designing a mixing ratio between an aggregate amount (kg) and a cement amount (kg) of a formed cement cured product.

The feature of the present invention in the above premise is that the specific surface area of the aggregate is corrected so that the mixing ratio in this aggregate / cement mixing ratio design method can assume that the thickness of the cement paste on each aggregate surface is substantially constant. Is determined based on the standardization ratio (S / C) obtained in this way, and the standardization ratio S / C is calculated by S / C = S ₁ / (C ₁ · R _S ), R _S = S _W2 / S _W1 There is to be. Here, S ₁ / C ₁ is the actual ratio between the aggregate amount (S ₁ ) and the cement amount (C ₁ ), and S _W1 is the apparent specific surface area (first specific surface area) of the reference aggregate determined as a reference in advance. ) (M ² / kg), S _W2 is the apparent specific surface area (second specific surface area) (m ² / kg) with respect to the change in the particle size distribution of the aggregate, and R _S is the first specific surface area (S _W1 ) It is a specific surface area ratio with the second specific surface area (S _W2 ). As shown in the above formula, the standardized ratio (S / C) is a standard determined in advance as a standard for the cement amount (C ₁ ) in the actual ratio (S ₁ / C ₁ ) between the aggregate amount and the cement amount. Specific surface area ratio between the apparent first specific surface area (S _W1 ) (m ² / kg) of the aggregate and the apparent second specific surface area (S _W2 ) (m ² / kg) with respect to the change in the particle size distribution of the aggregate ( Calculated by multiplying by R _S ). As shown in the above formula, the specific surface area ratio (R _S ) is calculated by dividing the second specific surface area (S _W2 ) by the first specific surface area (S _W1 ).

As an example of the aggregate / cement mixing ratio design method according to the present invention, the first specific surface area (S _W1 ) and the second specific surface area (S _W2 ) are S _W1 = S _W2 = ΣSi, Si = (4 · ^{π · ri 2) · ni =} 3 · Pi / (M · ri), is calculated by ^{Pi = M · (4.π · ri} 3/3) · ni. Here, Si is the apparent specific surface area (m ² / kg) of the i-th particle size aggregate arbitrarily extracted from the first to n-th particle sizes, and ri is the average radius of the i-th particle size aggregate (M), and ni is the number of particles (number / kg) of the i-th particle size aggregate contained per unit mass. Pi is the mass (kg) of the i-th particle size aggregate contained per unit mass, and M is the surface dry density (kg / liter) of the i-th particle size aggregate.

As another example of the aggregate / cement mixing ratio design method according to the present invention, the second specific surface area (S _W2 ) is determined in the range of 2 × 10 ^{3 to} 20 × 10 ³ (m ² / kg), While setting 1 specific surface area (S _W1 ) to 10 × 10 ³ (m ² / kg), the second specific surface area (S _W2 ) is in the range of 2 × 10 ^{3 to} 20 × 10 ³ (m ² / kg). The standardization ratio (S / C) when determined is in the range of 2.0 to 4.0.

  As another example of the aggregate / cement mixing ratio design method according to the present invention, the coarse particle ratio of the aggregate is in the range of 2.0 to 5.0.

  As another example of the aggregate / cement mixing ratio design method according to the present invention, the median particle size of the aggregate is in the range of 0.6 to 2.5 (mm), and 10 mm or less of those aggregates. Aggregates having a particle size of 90% or more of all aggregates.

  As another example of the aggregate / cement mixing ratio design method according to the present invention, the mixing ratio (W / C) (%) of water and cement forming the cement paste is in the range of 30 to 80 (%).

  As another example of the aggregate / cement mixing ratio design method according to the present invention, the aggregate is at least one of clinker ash, molten slag, and waste glass.

According to the aggregate / cement mixture ratio design method according to the present invention, the standardization obtained by correcting the specific surface area of the aggregate so that the thickness of the cement paste covering each aggregate surface can be assumed to be substantially constant. Since the mixing ratio of cement and aggregate is determined based on the ratio (S / C), even if the specific surface area of each aggregate is greatly changed by changing the particle size distribution of the aggregate, The mixing ratio of cement and aggregate can be determined uniformly by a predetermined calculation procedure. The aggregate / cement mixing ratio design method uses an apparent first specific surface area (S _W1 ) of a reference aggregate that is determined in advance as a correction value for a change in the specific surface area of the aggregate accompanying a change in the particle size distribution of the aggregate. ^(m 2 / kg) and using a second specific surface area of an apparent ^{_{(S W2) (m 2 /}} kg) the specific surface area of the ratio _{(R 3)} with respect to the change of the particle size distribution of aggregates, a specific surface area ratio (R _{Since the} standardization ratio (S / C) is obtained by multiplying the amount of cement ( _{S 1} ) by the amount of cement (C ₁ ), the mixing ratio of cement and aggregate corresponding to the change in the particle size distribution of the aggregate should be calculated reliably and easily. Can do. In the aggregate / cement mixture ratio design method, the standardization ratios (S / C) calculated for aggregates with different particle size distributions are almost the same value. Therefore, the mixing ratio of cement and aggregate can be easily designed, and the work efficiency in the field can be improved. In this aggregate / cement mixing ratio design method, since the mixing ratio of aggregate and cement is designed so that the calculated standardization ratio (S / C) is constant, aggregates having various particle size distributions are used. However, the thickness of the cement paste with respect to the aggregate surface can be kept substantially constant, and the properties during the kneading of the cement paste and the aggregate can be kept substantially constant.

The first specific surface area (S _W1 ) and the second specific surface area (S _W2 ) are S _W1 = S _W2 = ΣSi, Si = (4 · π · ri ² ) · ni = 3 · Pi / (M · ri), ^{Pi = M · (4.π · ri} 3/3) · aggregate / cement mixing ratio design method which is calculated by the formula ni is the first specific surface area from the particle size distribution obtained by a simple sieving test _{(S W1} ) And the second specific surface area (S _W2 ), the first and second specific surface areas (S _W1 ) can be obtained without requiring a complicated test and a complicated calculation and without taking time and effort in the field. , S _W2 ). The aggregate / cement mixing ratio design method calculates the first specific surface area (S _W1 ) and the second specific surface area (S _W2 ) based on the above formula, and calculates the first and second specific surface areas (S _W1). , S _W2 ), the standardization ratio (S / C) is calculated, and the mixing ratio of cement and aggregate is designed based on the calculated standardization ratio (S / C). The mixing ratio can be easily designed, and the work efficiency in the field can be improved. In this aggregate / cement mixing ratio design method, since the mixing ratio of aggregate and cement is designed so that the calculated standardization ratio (S / C) is constant, aggregates having various particle size distributions are used. However, the thickness of the cement paste with respect to the aggregate surface can be kept substantially constant, and the properties during the kneading of the cement paste and the aggregate can be kept substantially constant.

The second specific surface area (S _W2 ) is determined in the range of 2 × 10 ^{3 to} 20 × 10 ³ (m ² / kg), and the first specific surface area (S _W1 ) is set to 10 × 10 ³ (m ² / kg). While being set, the standardization ratio (S / C) when the second specific surface area (S _W2 ) is determined in the range of 2 × 10 ^{3 to} 20 × 10 ³ (m ² / kg) is 2.0 to 4.0. In the aggregate / cement mixing ratio design method in the range, the standardization ratio (S / C) is calculated using the second specific surface area (S _W2 ) in the range, and the standardization ratio (S / C) is calculated. Therefore, since the mixing ratio of cement and aggregate is designed, the mixing ratio of cement and aggregate can be easily designed in the field, and work efficiency in the field can be improved. In this aggregate / cement mixing ratio design method, since the mixing ratio of aggregate and cement is designed so that the calculated standardization ratio (S / C) is constant, aggregates having various particle size distributions are used. However, the thickness of the cement paste with respect to the aggregate surface can be kept substantially constant, and the properties during the kneading of the cement paste and the aggregate can be kept substantially constant.

  The aggregate / cement mixture ratio design method in which the coarse particle ratio of the aggregate is in the range of 2.0 to 4.0 uses the calculated standardization ratio (S / C) Since the mixing ratio of aggregate and cement is designed so that (%) is constant, the thickness of the cement paste with respect to the aggregate surface can be kept substantially constant, and the aggregate and cement The properties during kneading can be maintained substantially constant.

  The median particle size of the aggregate is in the range of 0.6 to 2.5 (mm), and the aggregate having a particle size of 10 mm or less among the aggregates accounts for 90% or more of all the aggregates. The aggregate / cement mixing ratio design method used is a standardized ratio (S / C) calculated while using an aggregate in which the particle size is in the above range and the aggregate having a particle size of 10 mm or less accounts for 90% or more. Since the mixing ratio of aggregate and cement is designed so as to maintain a constant, the thickness of the cement paste relative to the aggregate surface can be kept substantially constant, and the properties during mixing of the cement paste and aggregate can be maintained. It can be maintained substantially constant.

  The aggregate / cement mixing ratio design method in which the mixing ratio (W / C) (%) of the water and cement forming the cement paste is in the range of 30 to 80 (%), the water cement ratio is in the above range, The thickness of the cement paste with respect to the aggregate surface can be kept substantially constant, and the properties at the time of kneading the cement paste and the aggregate can be kept substantially constant. In this aggregate / cement mixing ratio design method, the mixing ratio of aggregate and cement is designed so that the calculated standardization ratio (S / C) is constant, and the water cement ratio (W / C) is within the above range. By doing so, it is possible to produce a hardened cement product having a necessary and sufficient compressive strength and impact resistance and having a predetermined void formed therein.

  The details of the aggregate / cement mixture ratio designing method according to the present invention will be described with reference to the accompanying drawings. FIG. 1 is a perspective view of a hardened cement material 10 shown as an example, and FIG. 2 is a partially enlarged view showing an AA line cross section of FIG. The hardened cement 10 is a hexahedron having an upper wall 11 and a lower wall 12 and side walls 13 located between the upper and lower walls 11 and 12. The hardened cement 10 is made by curing a mixture obtained by mixing a cement paste 14 (shown as hardened cement 14 in FIG. 2) and a plurality of aggregates 15 having a predetermined particle size.

  As shown in FIG. 2, a plurality of irregular voids 16 (spaces) in which the cement 14 and the aggregate 15 do not exist are formed inside the hardened cement 10. In the hardened cement material 10, when the voids 16 are present independently of each other, the voids 16 may be continuously present in a predetermined direction by connecting the voids 16 to each other. The surface 17 of the aggregate 15 is covered with a cement 14 having a substantially uniform thickness. In the hardened cement material 10, the aggregate 16 is encapsulated in the cement 14 alone, or the aggregate 16 is encapsulated in the cement 14 in a state where the adjacent aggregates 16 are partially in contact with each other. There is. The cement 14 is bonded to the aggregate 16 in contact with the surface 17 of the aggregate 16. Between the gaps 16, the cement 14 is bonded to each other, so that the shape of the hardened cement material 10 is maintained.

  An example of a procedure for manufacturing the hardened cement material 10 is as follows. The cement paste 14 and the aggregate 15 are mixed to form a mixture, the mixture is poured into a mold (not shown) having a predetermined shape, and the mold is immediately after filling. Remove or remove the mold until the mixture is cured. In addition, the cement hardened | cured material 10 is not limited to the quadrangular prism shape shown in figure, It can shape | mold into all other shapes, such as column shape and polygonal column shape, according to the shape of a formwork. The cement paste 14 is made by mixing raw material cement and water at a predetermined ratio, and has a predetermined viscosity. A ribbon mixer, a paddle mixer, a stirring hopper, a poni mixer, a power mixer, or the like can be used for mixing the raw material cement and water or the cement paste 14 and the aggregate 15.

The raw material cement is added with a solidifying material that effectively acts on the object to be solidified. Therefore, in cement, agglomeration of soil particles due to calcium ion exchange, and water is taken in to cause a hydration reaction, and a large amount of water containing acicular crystal ettringite (C ₃ A · 3CaSO ₄ · 32H ₂ O). Continuously promote multiple solidification reactions such as the formation of Japanese minerals. As the raw material cement, at least one of premix cement, Portland cement, blast furnace cement, fly ash cement, and silica cement is used. As the raw material cement, any of them may be used alone, or a mixed cement obtained by mixing them at a predetermined ratio may be used. Tap water, ground water, river water, etc. are used for water.

  For the aggregate 15, at least one of clinker ash, molten slag, and waste glass is used. The aggregates 15 are aggregates of aggregates having a variety of three-dimensional shapes, and the shapes thereof are not constant. As the aggregate 15, any one of clinker ash, molten slag, and waste glass may be used alone, or a mixed aggregate obtained by mixing these aggregates 15 at a predetermined ratio may be used. Clinker ash can be made by burning finely pulverized coal in a boiler at a coal-fired power plant. Inside the boiler, coal ash particles generated by combustion condense with each other and fall into a clinker hopper at the bottom of the boiler as a porous mass. The deposit is pulverized into sand by a pulverizer to produce clinker ash having a predetermined particle size. Clinker ash is fired at a high temperature (about 1300 ° C.), so that it has the properties of being chemically stable, hard to compact, and strong against clamping pressure, and has excellent air permeability and water retention.

  Molten slag is a vitreous substance formed by cooling and solidifying after incineration ash or the like heated under a high temperature condition of 1200 ° C. or higher is melted. The vitreous substance is pulverized by a pulverizer to produce molten slag having a predetermined particle size. Molten slag is mainly composed of silicon dioxide, aluminum oxide, and calcium oxide, and contains very little heavy metals (mercury, lead, cadmium, etc.). Since the heavy metals remaining in the molten slag are encapsulated in the Si—O 2 network structure of silicon dioxide, which is the main component of the molten slag, the elution is prevented. In addition, since dioxins contained in incineration ash are thermally decomposed by the high temperature conditions at the time of incineration ash melting, they do not remain in the molten slag. Waste glass can be made by pulverizing used glass to a predetermined particle size by a pulverizer. Waste glass is made by first crushing glass, removing metals, and further crushing secondary. Waste glass is classified by particle size with a sieve. As the pulverizer, a coarse pulverizer such as a jaw crusher, a gyratory crusher, a cone crusher, a hammark crusher, and a roll crusher, or a fine pulverizer such as a ball mill, a medium stirring mill, and a roller mill can be used.

After preparing the raw material cement and the aggregate 15, the mixing ratio of the aggregate amount (S) (kg) and the cement amount (C) (kg) is examined, and the mixing ratio of the aggregate 15 and the raw material cement is determined. design. When the particle size distribution of the aggregate 15 changes under the condition that the mixing ratio of the aggregate amount and the cement amount is constant, the specific surface area per unit mass of each aggregate 15 changes, and the surface 17 of the aggregate 15 is changed. The thickness of the cement paste 14 to be encapsulated becomes uneven. Therefore, by correcting the mixing ratio of the aggregate 15 and the raw material cement in accordance with the change in the particle size distribution of the aggregate 15 and the change in the specific surface area of the aggregate 15, the surface 17 of the aggregate 15 is changed. The thickness of the cement paste 14 to be encapsulated can be made substantially constant. Based on this, the mixing ratio of the aggregate amount and the cement amount in the case of making the hardened cement 10 is the thickness of the cement paste 14 on the surface 17 of each aggregate 15 after the cement paste 14 and the aggregate 15 are mixed. Is designed based on the standardized ratio S / C obtained by correcting the specific surface area of the aggregate 15. The standardization ratio S / C is calculated by the following formula.
(1) S / C = S ₁ / (C ₁ · R ₃ )
(2) R ₃ = S _W2 / S _W1
(A) S ₁ / C ₁ : Actual ratio of aggregate amount (S ₁ ) to cement amount (C ₁ ) (b) S _W1 : Apparent specific surface area of reference aggregate (first Specific surface area) (m ² / kg)
(C) S _W2 : Apparent specific surface area (second specific surface area) against change in aggregate particle size distribution (m ² / kg)
(D) R _S : Specific surface area ratio between the first specific surface area (S _W1 ) and the second specific surface area (S _W2 )

Standardization ratio S / C is the as shown in the expression, the amount aggregate _{(S 1)} and the cement content actual ratio _{(S 1} / _C 1) the cement content in the _{(C 1) (C 1)} , Apparent first specific surface area (S _W1 ) (m ² / kg) per unit mass of the reference aggregate determined in advance as a reference and apparent second specific surface area (S _W2 ) with respect to changes in the particle size distribution of the aggregate 15 ( m ² / kg) and the specific surface area ratio (R _S ). As shown in the above formula, the specific surface area ratio (R _S ) is calculated by dividing the second specific surface area (S _W2 ) by the first specific surface area (S _W1 ).

The first specific surface area (S _W1 ) and the second specific surface area (S _W2 ) are calculated by the following equations.
(3) S _W1 = S _W2 = ΣSi
(4) Si = (4 · π · ri ² ) · ni = 3 · Pi / (M · ri)
(5) Pi = M · ( 4.π · ri 3/3) · ni
(E) Si: Apparent specific surface area (m ² / kg) in the aggregate (actually used aggregate) of the i-th grain size arbitrarily extracted from the grain sizes 1 to n
(F) ri: average radius (m) in the i-th particle size aggregate
(G) ni: Number of particles of aggregate of the i-th particle size contained per unit mass (pieces / kg)
(H) Pi: Mass of the i-th particle size aggregate contained per unit mass (kg)
(I) M: Surface dry density (kg / liter) of the i-th particle size aggregate

In the calculation of the first specific surface area (S _W1 ) and the second specific surface area (S _W2 ), the calculation is performed assuming that the shape of the aggregate 15 is spherical. The average radius of the aggregate 15 is a value obtained by dividing the middle of the length between both ends of the particle size width of the aggregate 15 by 2. For example, when the particle diameter of the aggregate 15 is 0.6 to 1.2 mm, the average radius (ri) is ri = [[{(0.6 + 1.2) / 1000} / 2] / 2] = 0. 045 (m). Moreover, if it is the same kind of aggregate 15, it assumes that the specific surface area of the same particle size range is the same, and the aggregate 15 with a particle size of 10 mm or more is calculated as the particle size of 10-20 mm. The first and second specific surface areas (S _W1 , S _W2 ) defined in this way are not the same as the actual specific surface area of the aggregate 15, but are considered to be values proportional to the specific surface area. The standardized ratio S / C can be used as a parameter.

For calculation of standardization ratio (S / C) by these formulas, calculation of specific surface area ratio between first specific surface area (S _W1 ) and second specific surface area (S _W2 ), calculation of first specific surface area (S _W1 ) A personal computer (computer resource) (not shown) having a CPU and a memory is used. An application program for causing the computer to execute various calculations based on the above formula is stored in the memory of the computer. The application program is installed in the memory of the computer from the storage medium storing it. The CPU activates an application program from the memory based on the control by the operating system stored in the hard disk, calculates the first and second specific surface areas (S _W1 , S _W2 ) according to the activated application program, A specific surface area ratio between the specific surface area (S _W1 ) and the second specific surface area (S _W2 ) is calculated, and a standardized ratio (S / C) is calculated. Each numerical value necessary for the calculation is input to the computer via an input device such as a keyboard or a mouse connected to the computer.

In this aggregate / cement mixing ratio design method, the second specific surface area (S _W2 ) is determined in the range of 2 × 10 ^{3 to} 20 × 10 ³ (m ² / kg). The first specific surface area (S _W1 ) is set to 10 × 10 ³ (m ² / kg). While the first specific surface area (S _W1 ) is set to 10 × 10 ³ (m ² / kg), the second specific surface area (S _W2 ) is in the range of 2 × 10 ^{3 to} 20 × 10 ³ (m ² / kg). The standardization ratio (S / C) in the case defined by is in the range of 2.0 to 4.0. Thus, the values of the standardization ratios (S / C) calculated for the aggregates 15 having different particle size distributions are substantially the same. When the second specific surface area (S _W2 ) is less than 2 × 10 ³ (m ² / kg) and more than 20 × 10 ³ (m ² / kg), the formation state of cement paste around the aggregate and the formation state of voids The mixing ratio between the aggregate amount and the cement amount cannot be obtained uniformly, and an appropriate mixing ratio between the aggregate 15 and the raw material cement cannot be designed. The first specific surface area (S _W1 ) can also be set to a numerical value other than 10 × 10 ³ (m ² / kg).

In this aggregate / cement mixing ratio design method, the second specific surface area (S _W2 ) is set in the above range so that the value of the standardized ratio S / C is substantially constant, and the mixing ratio between the aggregate amount and the cement amount is set. Can be determined uniformly, and an appropriate mixing ratio of the aggregate 15 and the raw material cement can be reliably designed. Furthermore, even if the aggregate 15 having various particle size distributions is used, the thickness of the cement paste 14 with respect to the surface 17 of the aggregate 15 can be kept substantially constant, and the cement paste 14 and the aggregate 15 are kneaded. The property at the time can be maintained substantially constant.

  The mixing ratio (W / C) (%) of water and raw material cement forming the cement paste 14 is in the range of 30 to 80%. If the water-cement ratio is less than 30%, the bonding force between the cement 14 and the aggregate 15 and the bonding force between the cements 14 are weak, and the compressive strength of the cement cured product 10 is reduced. Therefore, the cured product 10 having excellent impact resistance. Can't make. If the water-cement ratio exceeds 80%, the cement paste 14 closes the void 16 of the cement cured product 10, and the predetermined void 16 cannot be formed in the cured product 10. In this aggregate / cement mixture design method, the necessary and sufficient compressive strength and impact resistance are achieved by adopting the standardized S / C and setting the water cement ratio (W / C) (%) within the above range. And a hardened cement material 10 in which a predetermined gap 16 is formed.

  These aggregates 15 have a median particle size in the range of 0.6 to 2.5 (mm), and aggregates 15 having a particle size of 10 mm or less of aggregates 15 are all aggregates 15. Of these, more than 90%. In this aggregate / cement mixing ratio design method, by using the aggregate 15 having an appropriate particle size, the cement cured product 10 having a predetermined porosity can be produced, and the aggregates 15 are reliably connected to each other. be able to. The particle size is tested according to JIS A 1102 “Aggregate Screening Test”, and the result is expressed by a particle size curve, a coarse particle ratio, and the like. The sieving test uses a screen sieve of 0.15, 0.3, 0.6, 1.2, 2.5, and 5.0 mm, and obtains the passage amount or residual amount of the aggregate sample in each sieve.

  The aggregate 15 has a coarse particle ratio in the range of 2.0 to 4.0. When the coarse particle ratio of the aggregate 15 is less than 2.0 and exceeds 4.0, the particle size distribution of the aggregate 15 becomes large, and the formation state of the cement paste around the aggregate and the formation state of the voids are greatly changed. The mixing ratio between the material amount and the cement amount cannot be determined uniformly, and an appropriate mixing ratio between the aggregate 15 and the raw material cement cannot be designed. The coarse particle ratio is 80, 40, 20, 10, 5, 2.5, 1.2, 0.6, 0.3, and 0.15 mm when a screening test is performed using a set of sieves. It is a value obtained by dividing the sum of mass percentages (integers) by 100 for the total amount of the aggregate material that does not pass through each sieve. In this aggregate / cement mixing ratio design method, since the coarse particle ratio of the aggregate 15 is in the above range, the value of the standardized ratio S / C is substantially constant, and the mixing ratio of the aggregate amount and the cement amount is uniform. Therefore, an appropriate mixing ratio of the aggregate 15 and the raw material cement can be designed. Furthermore, even if the aggregate 15 having various particle size distributions is used, the thickness of the cement paste 14 with respect to the surface 17 of the aggregate 15 can be kept substantially constant, and the cement paste 14 and the aggregate 15 are kneaded. The property at the time can be maintained substantially constant.

  FIG. 3 is a perspective view of the wall 18 to which the hardened cement material 10 is attached. The hardened cement material 10 made by using this aggregate / cement mixing ratio design method can be used as a sound absorbing material, water retaining concrete, and heat insulating material that form a soundproof wall. As shown in FIG. 3, the hardened cement 10 is disposed inside the wall material 19 and is fixed to the wall material 19 with an adhesive or a screw (not shown). The hardened cement 10 may be fixed to the wall material 19 with an adhesive or a screw in a state of being disposed outside the wall material 19, and may be attached to the wall material 19 while being stored between the wall materials 19. It may be fixed. Moreover, the cement hardened | cured material 10 can also be attached to a floor or a ceiling. Since this cement hardened | cured material 10 has the several space | gap 16 formed in the inside, it has the outstanding sound absorption property and heat insulation. When the clinker ash is used for the aggregate 15, the clinker ash has excellent air permeability and water retention, so that the hardened cement 10 can be optimally used as water retention concrete.

  In this aggregate / cement mixture ratio design method, the standardized ratio obtained by correcting the surface area of the aggregate 15 so that the thickness of the cement paste 17 covering the surface 17 of each aggregate 15 can be assumed to be substantially constant. Since the mixing ratio of the aggregate 15 and the raw material cement is designed based on (S / C), the specific surface area per unit mass of each aggregate 15 is increased by changing the particle size distribution of the aggregate 15. Even if it has changed, the mixing ratio of the aggregate 15 and the raw material cement can be obtained uniformly by a predetermined calculation procedure.

The aggregate / cement mixture ratio design method uses an apparent first specific surface area (S) of a reference aggregate that is determined in advance as a reference value as a correction value for a change in the specific surface area of the aggregate 15 due to a change in the particle size distribution of the aggregate 15. The specific surface area ratio (R _S ) between _W1 ) (m ² / kg) and the apparent second specific surface area (S _W2 ) (m ² / kg) with respect to the change in the particle size distribution of the aggregate 15 is used. Since the standardized ratio (S / C) is obtained by multiplying the ratio (R _S ) by the cement amount (C ₁ ), the mixing ratio of the aggregate 15 and the raw material cement corresponding to the change in the particle size distribution of the aggregate 15 is ensured. And it can be easily calculated.

In the aggregate / cement mixture ratio design method, since the standardized ratios (S / C) calculated in the aggregates 15 having different particle size distributions are substantially the same value, without depending on the experience and sense of the designer, The mixing ratio of the raw material cement and the aggregate 15 can be easily designed at the site, and the work efficiency at the site can be improved. In the aggregate / cement mixing ratio design method, the first specific surface area (S _W1 ) and the second specific surface area (S _W2 ) are calculated based on the above formula, and therefore, from the particle size distribution obtained by a simple sieving test The first and second specific surface areas (S _W1 , S _W2 ) can be obtained, the first and second specific surface areas (S _W1 and S _W2 ) do not require complicated tests and calculations, and do not require labor and time in the field. S _W1 , S _W2 ) can be calculated.

The perspective view of the cement hardened material shown as an example. The elements on larger scale which expand and show the AA line cross section of FIG. The perspective view of the wall which attached cement hardened | cured material.

Explanation of symbols

10 Cement cured product 14 Cement paste (cement)
15 Aggregate 16 Void 17 Surface

Claims (7)

Aggregate amount (kg) of hardened cement made by curing a mixture of cement paste containing a predetermined amount of moisture and aggregate having a predetermined range of particle size, with a plurality of voids formed inside In the aggregate / cement mixing ratio design method for designing the mixing ratio of the cement and the cement amount (kg),
The mixing ratio is determined based on a standardized ratio (S / C) obtained by correcting the specific surface area of the aggregate so that the thickness of the cement paste on each aggregate surface can be assumed to be substantially constant. The standardized ratio (S / C) is an apparent appearance of the reference aggregate that is defined in advance as a reference to the cement amount (C ₁ ) in the actual ratio (S ₁ / C ₁ ) between the aggregate amount and the cement amount. The specific surface area ratio (RS) between the first specific surface area (S _W1 ) (m ² / kg) and the apparent second specific surface area (S _W2 ) (m ² / kg) with respect to the change in the particle size distribution of the aggregate Calculated by multiplication, and the specific surface area ratio (RS) is calculated by dividing the second specific surface area (S _W2 ) by the first specific surface area (S _W1 ). Cement mixing ratio design method. The first specific surface area (S _W1 ) and the second specific surface area (S _W2 ) are:
S _W1 = S _W2 = ΣSi
Si = (4 · π · ri ² ) · ni = 3 · Pi / (M · ri)
^{Pi = M · (4.π · ri} 3/3) · ni
Si: Apparent specific surface area (m ² / kg) in the aggregate of the i-th particle size arbitrarily extracted from the particle size Nos. 1 to n
ri: average radius (m) in the i-th particle size aggregate
ni: Number of particles of the i-th particle size aggregate per unit mass (pieces / kg)
Pi: Mass of the i-th particle size aggregate contained per unit mass (kg)
M: Surface dry density of the i-th particle size aggregate (kg / liter)
The aggregate / cement mixing ratio design method according to claim 1 calculated by: The second specific surface area (S _W2 ) is determined in a range of ² × 10 ^{3 to} 20 × 10 ³ (m ² / kg), and the first specific surface area (S _W1 ) is set to 10 × 10 ³ (m ² / kg). The standardized ratio (S / C) when the second specific surface area (S _W2 ) is determined within the range while being set to) is in the range of 2.0 to 4.0. 2. The aggregate / cement mixing ratio design method according to 2.   The aggregate / cement mixture ratio design method according to any one of claims 1 to 3, wherein a coarse particle ratio of the aggregate is in a range of 2.0 to 5.0.   A median particle size of the aggregate is in a range of 0.6 to 2.5 (mm), and an aggregate having a particle size of 10 mm or less is 90% of all aggregates. The aggregate / cement mixture ratio design method according to any one of claims 1 to 4, wherein the aggregate / cement mixture ratio occupies at least 50%.   The aggregate / cement mixing ratio according to any one of claims 1 to 5, wherein a mixing ratio (W / C) (%) of water and cement forming the cement paste is in a range of 30 to 80 (%). Design method. The aggregate / cement mixture ratio design method according to any one of claims 1 to 6, wherein the aggregate is at least one of clinker ash, molten slag, and waste glass.

Images