JP2008308391A - Method for designing mix proportion of porous concrete - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for designing mix proportion of porous concrete by calculating the amount of each material to be used per unit volume of the porous concrete based on a design void content, physical properties of materials to be used and a theoretical formula for void content. <P>SOLUTION: The method for designing mix proportion of porous concrete uses the formula (1) for conducting mix proportion design to obtain a target void content after setting the target void content. In formula (1), Vc represents a void content (m<SP>3</SP>) of the porous concrete, Gg represents a percentage solid (%), Km represents a ratio of mortar coarse aggregate to void content and β represents a mass ratio of the amount of the mortar covering the entire surface of the coarse aggregate with a uniform thickness to the total amount of the mortar in a unit volume of the porous concrete. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a porous concrete blending design method for performing blending design of a material used based on a design void amount, a physical property value of the material used, and a void amount theoretical formula.

  In recent years, urban heat island phenomenon has become a problem due to the urban environment maintained with asphalt pavement and concrete structures and the consumption activities of fossil resources and so on. This can be attributed to a decrease in the green coverage ratio due to an increase in the artificial ground surface with the natural ground surface covered with concrete, and an increase in the nighttime temperature due to the release of heat stored in the concrete. At present, when the idea of emphasizing the global environment has been established, materials that give a load to the global environment (for example, concrete that causes the heat island phenomenon) tend to have a negative image. Therefore, in order to achieve sustainable development of cities, research and development of concrete as an eco-material for the purpose of environmental considerations, reduction of environmental burden or environmental response has become indispensable.

  Against this background, research and development of porous concrete having continuous voids has been actively conducted as an ecomaterial in recent years. Porous concrete has an environmental load reducing function and an environmental protection function such as water permeability, water retention, and low noise by holding a large amount of large voids. Furthermore, porous concrete can be used for vegetation bases and water purification treatments, and can be applied to the symbiotic field.

The amount of void is a factor that dominates the performance of porous concrete such as strength characteristics, durability, and additional performance. As a method for obtaining porous concrete having a desired void amount, for example, the following method has been proposed.
As a method for setting the void amount of porous concrete in advance, for example, “Research Committee Report 2003 on Establishment of Porous Concrete Design / Construction Method” by the Japan Concrete Institute, correction factor for the actual volume ratio of coarse aggregate A method of multiplying by α (0.95 to 0.98 as a general value of α) has been proposed.

In addition, as a method for pavement of porous concrete based on the porosity of porous concrete, the initial unit cement amount, unit coarse aggregate amount and polymer-based admixture are made constant, and the unit water amount is changed within a predetermined range. And obtaining a correspondence relationship between the mass of the specimen and the water cement ratio, obtaining a correspondence relationship between the water cement ratio and the calculated blending density, and obtaining a water cement ratio uniquely obtained from each correspondence relationship. Based on the above, a mixture design of porous concrete assuming a compacted state in which a predetermined porosity is obtained is performed, and a mixture obtained from a material based on the mixture design is spread with a finisher with a predetermined ground pressure, and the gap is A method for constructing a porous concrete pavement has been proposed in which compaction energy capable of securing a rate is introduced for compaction (Patent Document 1).
In addition, as a method of managing the void volume of porous concrete, etc., aggregates are classified according to particle size, models with the binders evenly attached around the aggregates are modeled, and the binders around the aggregates are simulated during the simulation. Uploaded to a computer a 3D particle element method program that can calculate the continuous voids in porous concrete that has been expanded to allow for deformation and also to allow for pressurized vibration compaction. Simulate the physical properties of each frame, blending quantities, and the undeformed amount of the binder as variables to determine the aggregate / void arrangement of porous concrete, actual volume ratio, continuous / independent void distribution, and continuous / independent void volume. A management method has been proposed (Patent Document 2).
Japanese Patent Laying-Open No. 2005-200964 JP-A-2005-47793

  However, the above-mentioned conventional methods are mostly analyzed based on the results, and theoretical clarification is insufficient. Therefore, the present condition is that the compounding design method of the porous concrete for obtaining the required void amount based on the theoretical formula has not been established.

  The present invention has been made in view of the above-mentioned background, and is based on the design void amount, the physical property value of the material used, and the pore volume theoretical formula. The purpose is to provide a design method.

As a result of diligent study to solve the above problems, the present inventor modeled the filling state of mortar in the voids between coarse aggregates in porous concrete, derived a theoretical equation for void amount, designed void amount, and used Based on the physical properties of the material and the theoretical formula of the void amount, the amount of each material used was calculated, and it was found that the compounding design of the porous concrete could be performed, and the present invention was completed.
That is, the present invention provides the following [1] and [2].

[1] A porous concrete blending design method characterized by performing blending design using the following formula (1) so as to obtain the void amount after determining a target void amount.

（式（１）中、Ｖｃはポーラスコンクリートの空隙量（ｍ^３）であり、Ｇｇは粗骨材の実積率（％）であり、Ｋｍはモルタル粗骨材空隙比であり、βはポーラスコンクリートの単位体積中の全モルタル量に対する、粗骨材の全面を均一な厚みで被覆するモルタル量の質量割合である。）

(In Formula (1), Vc is the void volume (m ³ ) of porous concrete, Gg is the actual volume ratio (%) of coarse aggregate, Km is the mortar coarse aggregate void ratio, and β is porous. (This is the mass ratio of the amount of mortar that covers the entire surface of the coarse aggregate with a uniform thickness to the total amount of mortar in the unit volume of concrete.)

[2] The blending design method for porous concrete according to claim 1, wherein β in the formula (1) is represented by the following formula (2).

（式（２）中、βはポーラスコンクリートの単位体積中の全モルタル量に対する、粗骨材の全面を均一な厚みで被覆するモルタル量の質量割合であり、β_ｐはポーラスコンクリート中のモルタルを構成するペーストが、βに及ぼす影響の度合いを示す係数であり、β_ｓはポーラスコンクリート中のモルタルを構成する細骨材が、βに及ぼす影響の度合いを示す係数であり、Ｇｓは細骨材の実積率（％）であり、Ｋｐはペースト細骨材空隙比である。）

(In the formula (2), β is the mass ratio of the mortar amount covering the entire surface of the coarse aggregate with a uniform thickness to the total mortar amount in the unit volume of the porous concrete, and β _p is the mortar in the porous concrete. The constituent paste is a coefficient indicating the degree of influence on β, β _s is a coefficient indicating the degree of influence of the fine aggregate constituting the mortar in the porous concrete on β, and Gs is the fine aggregate. (The actual volume ratio (%) of K, and Kp is the paste fine aggregate void ratio.)

  According to the compounding design method for porous concrete of the present invention, the amount of each material used per unit volume of porous concrete is calculated based on the design void amount, the physical property value of the material used, and the theoretical amount of void amount. Thus, porous concrete having a required void amount (specifically, a void amount within an error range of about ± 1.5% of the designed void amount) can be obtained.

Hereinafter, the present invention will be described in detail.
In the blending design method for porous concrete according to the present invention, after setting a target void amount, blending design is performed using the following equation (1) so that the void amount is obtained.

（式（１）中、Ｖｃはポーラスコンクリートの空隙量（ｍ^３）であり、Ｇｇは粗骨材の実積率（％）であり、Ｋｍはモルタル粗骨材空隙比であり、βはポーラスコンクリートの単位体積中の全モルタル量に対する、粗骨材の全面を均一な厚みで被覆するモルタル量の質量割合である。）

(In Formula (1), Vc is the void volume (m ³ ) of porous concrete, Gg is the actual volume ratio (%) of coarse aggregate, Km is the mortar coarse aggregate void ratio, and β is porous. (This is the mass ratio of the amount of mortar that covers the entire surface of the coarse aggregate with a uniform thickness to the total amount of mortar in the unit volume of concrete.)

[1. Formulation of void volume in porous concrete]
[(1) Modeling the void state of porous concrete]
FIG. 1 is an explanatory diagram showing a model (hereinafter referred to as “POC model”) that schematically illustrates the state of coarse aggregate 2, mortar 3, and void 4 constituting porous concrete 1. Moreover, FIG. 2 is explanatory drawing which modeled two limit states of porous concrete, (a) shows a coarse aggregate covering state, (b) shows a space | gap filling state.
The theoretical formula of the void amount in the above formula (1) can be derived from the POC model shown in FIG.
The mortar 3 serving as a binder for the coarse aggregate 2 is a gap (see FIG. 2A) that covers the entire surface of the coarse aggregate 2 with a uniform thickness, and voids formed between the particles of the coarse aggregate 2 (see FIG. Hereinafter, it is considered to be composed of a portion 3b (the remainder of the mortar 3 excluding the portion 3a; see FIG. 2B) that partially fills the gap between coarse aggregate particles. When the mortar 3 is composed only of the portion 3a that covers the coarse aggregate 2 with a uniform thickness, the void amount is considered to be the maximum (maximum void amount) (coarse aggregate covered state in FIG. 2A).
On the other hand, when the mortar 3 is filled in the voids between the coarse aggregate particles, the void amount is considered to be the minimum (minimum void amount) (the void filling state in FIG. 2B).
The POC model shown in FIG. 1 represents a state in which a mortar 3a in a coarse aggregate covering state and a mortar 3b in a void filling state are mixed, and is considered to be close to an actual porous concrete state. . The inventor has a limit state (hereinafter, also referred to as (a) coarse aggregate coating state), a limit state (hereinafter, also referred to as (b) void filling state), and a minimum void amount. The void amount and unit coarse aggregate bulk volume in the POC model were derived as follows.

Here, the unit coarse aggregate bulk volume Rg is the bulk volume of the coarse aggregate in 1 m ^{3 of} concrete. The unit coarse aggregate bulk volume Rg is a value obtained by dividing the unit coarse aggregate amount G (kg) in the surface dry state by the unit volume mass Tg ′ (kg / m ³ ) of the surface coarse aggregate. It is represented by the following formula (3). The unit volume mass Tg ′ (kg / m ³ ) of the coarse aggregate in the surface dry state is the unit volume of the coarse aggregate obtained based on JIS A1104 (Aggregate unit volume mass and actual volume ratio test method). It is a value obtained by multiplying the mass Tg (kg / m ³ ) by the water absorption rate Qg of the coarse aggregate.

[(A) void amount and unit coarse aggregate bulk volume in coarse aggregate covering state]
Compared to the case where the coarse aggregates are in point contact with each other in a state where there is no mortar, the coarse aggregate covering state is formed by forming a mortar layer having a uniform thickness on the entire surface of the coarse aggregate. This is a state in which the distance between them is uniformly increased, and the void amount is considered to be equal regardless of the amount of mortar. Therefore, the void amount Vc _u (m ³ ) in the coarse aggregate covered state is equivalent to the void amount of the coarse aggregate when there is no mortar. Therefore, when the actual volume ratio of the coarse aggregate is Gg, As shown in Formula (4), it is shown by the amount of voids between coarse aggregate particles (1-Gg (m ³ )).

Next, the unit coarse aggregate bulk volume Rg _u in the coarse aggregate covered state is obtained.
In the coarse aggregate covered state, it is considered that the coarse aggregate particle distance increases and the unit coarse aggregate bulk volume Rg decreases due to an increase in the coating thickness of the mortar. In the following, this consideration is demonstrated from the theoretical formula.
First, the mortar coarse aggregate void ratio (hereinafter referred to as Km) is used to determine the unit mortar volume m _u (m ³ ) in the coarse aggregate covered state.
Mortar coarse aggregate void ratio Km is the ratio of the void volume between the coarse aggregate particles in the concrete 1 m ³ Vg units mortar volume m for (m ³⁾ (m ^3), represented by the following formula (5) .

Using the above equation (5) and assuming that the unit coarse aggregate volume in the coarse aggregate covered state is g _u (m ³ ), the unit mortar volume m _u (m ³ ) in the coarse aggregate covered state is (6).

Further, the unit volume mass Tg (kg / m ³ ) of the coarse aggregate is expressed by the following formula (7) using the surface dry density ρg (kg / m ³ ) of the coarse aggregate and the actual volume ratio Gg of the coarse aggregate. ).

By substituting and organizing equation (7) into equation (3) above, the unit coarse aggregate volume g _u (m ³ ) is obtained by the following equation (8).

The sum of the unit mortar volume m _u (m ³ ), the unit coarse aggregate volume g _u (m ³ ), and the void amount Vc _u (m ³ ) between the coarse aggregate particles in the coarse aggregate covering state is 1 m ^3. (Equation (9) below).

Substituting the above formulas (4), (6), and (8) into the above formula (9) and rearranging, the following formula (10) is obtained. As shown in the following formula (10), it became clear that the unit coarse aggregate bulk volume Rg _u in the coarse aggregate covered state becomes smaller as the mortar coarse aggregate void ratio increases.

[(B) Void amount and unit coarse aggregate bulk volume in void filling state]
The unit volume of porous concrete including voids is 1 m ³ , and the unit coarse aggregate bulk volume Rg _l in the void filling state matches the unit volume of porous concrete (Rg _l = 1).
The sum of the unit mortar volume m _l (m ³ ), the unit coarse aggregate volume g _l (m ³ ), and the void amount Vc _l (m ³ ) between the coarse aggregate particles in the void filling state is also 1 m ³ .
Here, when the above equation (5) is used, the unit mortar volume m _l (m ³ ) in the void filling state is represented by the following equation (11).

Further, the unit coarse aggregate volume g _l (m ³ ) in the space filling state is expressed by the following formula (12).

上記の式（１１）及び式（１２）を、単位モルタル体積ｍ_ｌ（ｍ^３）、単位粗骨材体積ｇ_ｌ（ｍ^３）、および、粗骨材粒子間の空隙量Ｖｃ_ｌ（ｍ^３）の和が１ｍ^３となる式に代入すると、空隙充填状態における粗骨材粒子間の空隙量Ｖｃ_ｌ（ｍ^３）は、下記の式（１３）で表される。

The above equation (11) and (12), the unit mortar volume _m l ^(m 3), the unit coarse aggregate volume _g l ^(m 3), and the void volume between the coarse aggregate particles _Vc l ^{(m 3} When the sum of) is substituted into the equation as a 1 m ^3, the void volume Vc l _(m 3 between the coarse aggregate particles in the air gap filling ^state) is represented by the following equation (13).

[(C) Porosity and unit coarse aggregate bulk volume in POC model]
FIG. 3 is an explanatory diagram showing a POC model. As described above, the POC model is a part in which the mortar as a binder uniformly covers the entire surface of the coarse aggregate with a uniform thickness, and a part that partially fills the gap between the coarse aggregate particles formed by this part. It is a model that consists of
As shown in FIG. 3, the ratio of the mortar covering the coarse aggregate is β (beta), and the ratio of the mortar partially filling the gaps between the coarse aggregate particles is (1-β). β is the mass ratio of the mortar amount covering the entire surface of the coarse aggregate with a uniform thickness to the total mortar amount in the unit volume of the porous concrete.
When obtaining the unit coarse aggregate bulk volume in the POC model, only the mortar covering the coarse aggregate needs to be considered.
When the unit mortar volume of the porous concrete is m (m ³ ), the unit volume of the mortar covering the coarse aggregate is β × m (m ³ ). Therefore, in the porous concrete considering only the mortar covering the coarse aggregate, the following formula (14) is established, and the unit coarse aggregate bulk volume Rg is obtained by the following formula (15). From this equation (15), it was found that the unit coarse aggregate bulk volume in the POC model decreases as the mortar coarse aggregate void ratio Km increases.

Since the sum of unit mortar volume m (m ³ ), unit coarse aggregate volume g (m ³ ) and porous concrete void volume Vc (m ³ ) in porous concrete is 1 m ³ , porous concrete void volume Vc Can be obtained from the following equation (1) which is a fractional function of the mortar coarse aggregate void ratio Km.

FIG. 4 shows the relationship between the POC model and the mortar coarse aggregate void ratio Km in each limit state (coarse aggregate covering state and void filling state) and the void amount Vc of the porous concrete.
As shown in FIG. 4, the relational expression between the mortar coarse aggregate void ratio Km and the porous concrete void amount Vc in the POC model is a fractional function passing through a region sandwiched between the coarse aggregate covered state and the void filled state. , (0,1-Gg) and (Gg / (Gg-β), 0).
Therefore, the unit coarse aggregate bulk volume of the porous concrete becomes smaller as the target void amount Vc or the ratio β of the mortar covering the coarse aggregate is larger, and is not constant.
From the above results, the basic form of the void amount (theoretical) equation of porous concrete could be derived.

[(2) Ratio of mortar covering coarse aggregate]
Next, β, which is the ratio of the mortar covering the coarse aggregate, will be examined.
The ratio β of the mortar covering the coarse aggregate is considered to be a constant that varies depending on the fluidity of the mortar. Here, in order to subdivide the factors affecting the mortar covering the coarse aggregate, the mortar is further divided into paste and fine aggregate.
The unit volume of the mortar covering the coarse aggregate in the POC model can be represented by β × m (m ³ ). When the coefficients indicating the degree of influence of the volume ratio of the paste and fine aggregate constituting the mortar in the concrete 1 m ³ on the mortar ratio β covering the coarse aggregate are β _p and β _s , respectively, the coarse aggregate The ratio β of the mortar to be coated can be expressed by the following formula (16). Equation (16) shows that when β _p or β _s is a negative value, the ratio of the paste or fine aggregate in the mortar increases, so that the ratio β of the mortar covering the coarse aggregate decreases. Show.

Paste fine aggregate void ratio (hereinafter referred to as Kp.) Is the ratio of the unit volume of fine aggregate interparticle voids in the concrete 1m ³ Vs ^{(m 3)} units of the paste volume p ^{(m 3).} The paste fine aggregate void ratio Kp is calculated by the following formula (17) from the fine aggregate actual volume ratio Gs (%), unit paste volume p (m ³ ), and unit fine aggregate volume s (m ³ ). Desired.

According to the above formula (17) and the above formula (5), the unit paste volume p (m ³ ) and the unit fine aggregate volume s (m ³ ) should be expressed by the following formulas (18) and (19), respectively. Can do.

By substituting the above formulas (18) and (19) into the above formula (16), the following formula (2) is obtained. According to this equation (2), when the ratio β of the mortar covering the coarse aggregate becomes β _p = β _s, it becomes a constant regardless of the paste fine aggregate void ratio Kp, except that β _p = β _s Is a fractional function of the paste fine aggregate ratio Kp.

Table 1 shows the unit coarse aggregate bulk volume Rg, the void volume Vc of the porous concrete, and the ratio β of the mortar covering the coarse aggregate in the POC model.
As shown in Table 1, the pore volume Vc (theoretical value) of porous concrete is the blending conditions Km (mortar coarse aggregate void ratio) and Kp (paste fine aggregate void ratio), and the actual volume ratio of the aggregate. A certain Gg (actual volume ratio of coarse aggregate) and Gs (actual volume ratio of fine aggregate), β _p which is an experimental constant (volume ratio of paste constituting mortar in 1 m ^{3 of} concrete covers the coarse aggregate) the volume percentage of fine aggregate constituting the mortar coefficient) and beta _{s (in} concrete 1 m ³ indicating the degree of influence on the mortar ratio beta to indicates the degree of influence on the mortar ratio beta coating the coarse aggregate Coefficient).

[(3) Air bubbles in porous concrete]
Entrapped air and entrained air exist as air bubbles in ordinary concrete. It has been confirmed by experiments that the amount of air in the porous concrete is 0.025 to 0.035 m ³ . It has also been confirmed by the microfocus X-ray CT scan system that all the gaps are continuous. Further, it has been confirmed that the continuous void amount is about 0.02 to 0.03 m ³ smaller than the total void amount.
From these facts, it can be inferred that air bubbles may be included in the difference between the total void amount and the continuous void amount in the porous concrete.

Here, the effect of air bubbles in porous concrete is examined. In this specification, entrapped air and end drained air are defined as “air bubbles”, and the unit volume thereof is defined as “air amount”.
It is assumed that all air bubbles in the porous concrete are included in the paste, and the amount of air included in the paste does not vary depending on the mortar coarse aggregate void ratio Km and the paste fine aggregate void ratio Kp.
When the amount of air in the porous concrete is Va (m ³ ), the air volume ratio Ap and Am of the paste and the mortar can be expressed by the following equations (20) and (21), respectively. Further, the air volume ratio Am of the mortar is calculated by using the above formula (17) and formula (20), as shown in the following formula (22), the paste air volume ratio Ap, the paste fine aggregate gap It can be shown by the ratio Kp and the actual volume ratio Gs of the fine aggregate.

An attempt is made to calculate the amount of air in the porous concrete using the mortar air volume ratio Am shown in the equation (22).
In porous concrete, voids are formed between coarse aggregate particles. Therefore, as shown in the following formula (23), the unit bulk volume (m / 1-Am) (m ³ ) and unit of mortar having air bubbles The sum of the coarse aggregate volume g (m ³ ) is less than 1.

By obtaining the unit mortar volume m (m ³ ) and the unit coarse aggregate volume g (m ³ ) with reference to the above formulas (5) and (15), and substituting them into the above formula (23), Equation (24) is obtained.

The above formula (24) shows the limit of formation of the gap between coarse aggregate particles, that is, the mortar coarse aggregate gap ratio that becomes the boundary between porous concrete and ordinary concrete, and this boundary value is Kmx.
The unit mortar volume m (m ³ ) in the porous concrete when the mortar coarse aggregate void ratio Km is less than the boundary value Kmx is expressed by the following formula (25) according to the above formula (5) and formula (15). Is required. From this equation (25), the air amount Va (m ³ ) of the porous concrete is expressed by the following equation (26): the ratio β of the mortar covering the coarse aggregate, the air volume ratio Am of the mortar, the mortar It is obtained from the coarse aggregate void ratio Km and the actual volume ratio Gg of the coarse aggregate. The air bubbles of the porous concrete are included in the voids of the porous concrete and are considered to be part of the independent voids.

On the other hand, the void amount Ac (m ³ ) of ordinary concrete when the mortar coarse aggregate void ratio Km is greater than or equal to the boundary value Kmx is expressed by the following equation (27), and a fractional function with y = Am asymptotic line It is.

FIG. 5 shows the mortar coarse aggregate void ratio Km, void volume Vc (m ³ ), air volume Va (m ³ ) and ordinary concrete of porous concrete having the same conditions other than the mortar coarse aggregate void ratio Km. The relationship with the air amount Ac (m ³ ) is shown.
The intersection of the lines indicating these relationships can be represented by (Kmx, (1-Gg) Am / {1- (1-Am) β}). Theoretically, ordinary concrete has the smallest amount of air when Km = Kmx, and the amount of air at that time is (1-Gg) Am / {(1- (1-Am) β} (m ³ ).
Based on the above results, porous concrete and ordinary concrete can be classified as shown in Table 2 according to the range of the mortar coarse aggregate void ratio Km.

[2. Classification of concrete based on material composition]
As described above, a theoretical model (POC model) related to the voids in porous concrete was devised, and a void amount theoretical formula (formula (1)) was derived from this model. From this theoretical formula of void amount, the formation limit of voids between coarse aggregate particles of porous concrete was obtained, and as shown in Table 2 above from the relationship between the void amount Vc and the air amount Va, porous concrete and ordinary concrete are mortar coarse. It was shown that classification can be made within the range of the aggregate void ratio Km.
Further, by applying this concept to the fine interaggregate particle gap, the paste fine aggregate gap ratio Kp is used to determine the formation limit of the fine aggregate interparticle gap, and the paste fine aggregate gap ratio Kp It is considered that concrete can be classified by range.
When the boundary value between porous concrete and ordinary concrete is Kpx, it is considered that porous concrete including voids between fine aggregate particles is in the region of Kp <Kpx, and that of ordinary concrete is in the region of Kp ≧ Kpx.

  Here, by using the mortar coarse aggregate void ratio Km and the paste fine aggregate void ratio Kp, the positioning of the porous concrete is shown, and the mixing conditions of the porous concrete for experimental verification of the void amount theoretical formula are examined. Moreover, the concept about the boundary values Kmx and Kpx of porous concrete and normal concrete is shown.

FIG. 6 shows a conceptual diagram of concrete expressed when the horizontal axis is the mortar coarse aggregate void ratio Km and the vertical axis is the paste fine aggregate void ratio Kp.
The range of Km and Kp was 0 to infinity (∞), and Kmx and Kpx were used as the boundary between porous concrete and ordinary concrete. In FIG. 6, NFC indicates concrete (No-Fines Concrete) that does not include fine aggregate. Each region in FIG. 6 will be described below.
On the horizontal axis (x-axis), only aggregate is shown, and Km = infinity (∞) shows only fine aggregate. Only the coarse aggregate is shown on the vertical axis (y-axis). Km = infinity (∞) indicates mortar, and Kp = infinity (∞) indicates paste. On the Kp = infinity (∞) line, NFC is indicated.

In FIG. 6, a region I is a region of Km ≧ Kmx and Kp ≧ Kpx, and shows normal (ordinary) concrete having no voids between aggregate particles. The positions of the various concretes in the figure are approximate positional relationships because the concepts of the mortar coarse aggregate void ratio Km, the paste fine aggregate void ratio Kp, and the water cement ratio (W / C) are not included.
The concrete in this region is a solid concrete mainly focusing on strength and durability, but includes aerated concrete containing a large amount of air bubbles in the binder.

In FIG. 6, regions II, III, and IV are regions of concrete including aggregate interparticle voids, and indicate porous concrete.
In FIG. 6, it is considered that a continuous void having a relatively large void diameter can be formed in region II because the void between coarse aggregate particles remains. This is a region of porous concrete that can be improved in strength and durability by improving the performance of mortar, and porous concrete that has been put into practical use is almost included in this region II. The example using the void amount theoretical formula is intended for porous concrete included in the region II. Also, Kp = infinity (∞) is porous concrete (No-Fine Porous Concerte, NF-POC) that does not contain fine aggregate.

In FIG. 6, in the region IV, the voids between the fine aggregate particles remain, so it is considered that continuous voids having a relatively small void diameter can be formed. Km = infinity (∞) is porous mortar (POM).
In FIG. 6, region III is considered to be porous concrete having both continuous voids having a relatively large void diameter in region II and continuous voids having a relatively small void diameter in region IV. Since the amount of paste becomes very small, it is considered difficult to ensure strength and durability.

As shown in FIG. 6, when concrete is classified, porous concrete can be defined as “concrete having voids between aggregate particles excluding air bubbles such as entrapped air and entrained air”.
In addition, when classifying concrete based on the mortar coarse aggregate gap ratio Km and paste fine aggregate gap ratio Kp, the classification of the coarse aggregate and the fine aggregate as a basis is very important.
As coarse aggregate of porous concrete, use 5 to 2.5 mm aggregate (No. 7 crushed stone) included in the particle size range of ordinary fine aggregate for concrete or small particle size single crushed stone of 2.5 mm or less. There is. This is a method of classifying an aggregate serving as a skeleton that forms a gap between aggregate particles having a relatively large void diameter as a coarse aggregate and classifying an aggregate contained in a mortar as a fine aggregate.

In the examples shown below, the fine aggregate in the porous concrete is a continuous fine-grain concrete fine aggregate having a maximum aggregate size of 5 mm or less forming mortar, and the other aggregates are small or large in particle size. All will be treated as coarse aggregate.
In the present specification, “continuous particle size” means having a particle size distribution that is continuous up to the maximum size without providing a lower limit particle size.
For example, porous concrete using a single particle size aggregate having a particle size of 5 mm or less is “porous concrete using a small particle size coarse aggregate” and is made of a fine aggregate and paste that does not contain coarse aggregate. Separated from (porous mortar).

  In the following, with respect to the formula (1) of the void amount formulated in “1. Formulation of void amount in porous concrete”, the particle size of the coarse aggregate (continuous particle size) in the porous concrete indicated by region II in FIG. The suitability of the above formula (1) is verified by the example in which the range, the mortar coarse aggregate void ratio Km, and the paste fine aggregate void ratio Kp are changed.

[Example]
1. Method of implementation (1) Materials used As cement (binding material), ordinary Portland cement (density: 3.16 g / cm ³ ), and as admixture / admixture, inorganic admixture exclusively for porous concrete for road pavement (Ad1, Density: 2.26 g / cm ³ ), inorganic admixture exclusively for porous concrete for landscape pavement (Ad2, density: 2.16 g / cm ³ ), high-performance AE water reducing agent (SP8SB (SP)).
The admixture was used as the inner part of cement, and the admixture was used as the inner part of water.
The physical property values of the aggregates used are shown in Table 3 below. As the fine aggregate, a fine aggregate for concrete (SA, SB, SC) having a particle size range of 0 to 5 mm was used. As the coarse aggregate, an aggregate (No. 6 crushed stone) having a particle size range of 13 to 5 mm and an aggregate (No. 7 crushed stone) having a particle size range of 5 to 2.5 mm were used. In addition, an aggregate having a particle size range of 13 to 10 mm and an aggregate having a particle size range of 10 to 5 mm and an aggregate having a particle size range of 10 to 5 mm were used as the coarse aggregate. The physical properties of the aggregate are shown in Table 3 below.

(2) Mixing The mixing level of porous concrete is shown in Table 4 below.
In consideration of the convenience of analytical verification of the void amount equation (1), the compounding design is such that the unit coarse aggregate bulk volume Rg is 1.0, and the design void amount Vd ′ (m ³ ) is expressed by the following equation ( 28) was used to determine the actual aggregate ratio Gg of the coarse aggregate and the mortar coarse aggregate void ratio Km. Examples of blending of porous concrete in which the mortar coarse aggregate void ratio Km is changed are shown in Table 5 (Porous concrete showing blending example 1 (using G1305A)) and Table 6 (Porous concrete showing blending example 2 (using G0502)).
In Tables 4 to 6, G is a unit coarse aggregate amount (kg), S is a unit fine aggregate amount (kg), W is a unit water amount (kg), C is a unit cement amount (kg), W / B represents a water binder ratio, and W / C represents a water cement ratio.

(3) Kneading method Porous concrete is kneaded by using a forced kneading mixer, putting coarse aggregate, fine aggregate, cement and admixture into the mixer, mixing for 15 seconds, and then adding water. And kneading for 5 minutes.

(4) Measuring method of void volume The void volume of porous concrete was measured by the settlement method. In FIG. 7, the measuring method of the void amount of the porous concrete by the settlement method is shown.
As shown in FIG. 7, a steel mold 6 having a diameter of 10 cm and a height of 20 cm is placed on the vibration table 5, and a sample 7 (mass Wtp; 2.60 kg) is put into the mold 6. Then, a weight 8 of 4 kg is placed on the mold 6, the sample 7 together with the steel mold 6 is vibrated, the height and diameter of the sample 7 in the mold 6 are measured, and porous concrete is measured. The volume V (m ³ ) of was determined. The vibration table 5 having a vibration frequency of 300 rpm and an excitation force of 823 N was used, and the excitation time was 2 minutes.
Using the theoretical unit volume mass T (kg) of the porous concrete calculated as having no air, the experimental value Vt (m ³ ) of the void amount with respect to 1 m ³ of concrete was obtained from the following formula (29). .
The void amount of the porous concrete obtained by this test method represents the amount of remaining void of the porous concrete when the same vibration energy was applied, and the excitation time was set to a time for almost full compaction.

(5) Basic physical property test of binder The fluidity and the amount of air were measured as the basic physical properties of a paste or mortar that becomes a binder for porous concrete shown in Table 4 above.
A flow test was conducted as a test for evaluating the fluidity of the paste and mortar. The test is performed according to JIS R 5201 “Physical test of cement”, and the flow value (15 strokes) given 15 drop motions according to JIS and the flow value (0 strokes) not giving drop motions are measured. did.
The amount of air in the fresh paste and mortar was measured with reference to JIS A 1142, “Testing method based on compressive strength of mortar of fine aggregate containing organic impurities”. As the container, a metal cylindrical container shown in JIS A 5002 “Structural Lightweight Concrete Aggregate” was used. The volume of this container is about 500 cm ³ . The volume of the container was calculated by accurately measuring the mass of water required to fill the container before testing.

2. Basic physical properties of binders Table 7 below shows the results of basic physical property tests of pastes and mortars used as binders for porous concrete.
When C × 1% of the high-performance AE water reducing agent (SP) was used, the paste and mortar were very hard and stuffy and had no fluidity. In the measurement of the air amount, sufficient compaction was performed with a vibration table (vibration table) so that a gap due to insufficient compaction did not remain.
When the admixtures Ad1 and Ad2 were used, the fluidity was very high, but the paste using the admixture Ad2 was separated.
The amount of air was a little larger than the range of 0.027 to 0.058 m ³ . This is because, in the air amount test, vibration compaction was performed, but the paste and mortar were extremely viscous and poor in fluidity, and therefore could not be defoamed.

3. Results of measurement of void volume Fig. 8 shows, for each coarse aggregate, the mortar coarse aggregate void ratio Km at each paste fine aggregate void ratio Kp, the void volume of porous concrete (m ³ ) (the void volume experimental value Vt). And the regression value of void volume (theoretical value of void volume)). The verification of the void amount formula will be described later using these results.

4). Calculation of the ratio β of the mortar covering the coarse aggregate Using the least square method according to the relational expression of the void amount Vc (m ³ ) of the POC model shown in Table 1 and the result of the example (experimental amount of void amount). Then, the result of the example (experimental value of void amount) was regressed with the equation of the above equation (1), and the ratio β of the mortar covering the coarse aggregate in the void model of the porous concrete was obtained.
Table 8 shows the calculation result of the ratio β of the mortar covering the coarse aggregate. Further, FIG. 8 shows, for each coarse aggregate, mortar coarse aggregate void ratio Km and void amount (void amount experimental value Vt and regression value (void amount theoretical value) Vc) at each paste fine aggregate void ratio kp. ).
Due to the relationship between the experimental value of the void amount shown in FIG. 8 and the regression value based on the experimental value of the void amount, these determination coefficients (R square values) except for one point (0.73) are determined coefficients (R square values). Is 0.89 or more. From this, the relational expression of the above formula (9) shows the result of the example (experimental amount experimental value) with sufficient accuracy by determining the ratio β of the mortar covering the coarse aggregate. I understood.
Further, when the paste fine aggregate void ratio Kp is decreased, the ratio β of the mortar covering the coarse aggregate tends to increase, so that the distance between coarse aggregate particles increases and the unit coarse aggregate bulk volume decreases. Will do.

5. Calculation of coefficients β _p and β _{s Using} the paste fine aggregate gap ratio Kp and the ratio of the mortar covering the coarse aggregate β shown in Table 8 above, the experimental results are expressed in the form of the above formula (2). Regression was performed to determine the coefficients β _p and β _s . FIG. 9 shows the relationship between the coefficients β _p and β _s and the coarse aggregate average particle size. The coarse aggregate average particle size was an average value of the maximum particle size and the minimum particle size of the coarse aggregate.
As shown in FIG. 9, the coefficient β _s decreases as the coarse aggregate average particle size increases, and is very large, four times or more compared to the coefficient β _p. Therefore, the ratio β of the mortar covering the coarse aggregate It became clear that the influence of the amount of fine aggregate was large.
The coefficient beta _p negative value observed, the increase of the amount of paste, the ratio beta of the mortar coating the coarse aggregate is decreased. However, the precondition, beta is zero or greater, when the coefficient beta _p is negative, the paste fine aggregate void ratio Kp capable above equation (14) is applied, so that the upper limit is present . When the upper limit of the paste fine aggregate void ratio Kp and _{Kp lim,} the _{Kp lim,} coarse aggregate from becoming a ratio beta = 0 for the mortar coating, the above equation _{(14), Kp lim} is below (30).
Above Kp _lim , there is no mortar covering the coarse aggregate, and it is considered that the coarse aggregate particles are in contact with each other as in the void filling state.

Table 9 below shows the results of Kp _lim at each level. When the mortar used as the binder is equivalent, the Kp _lim tends to increase as the coarse aggregate average particle size increases.

6). Theoretical void volume value obtained from the blending conditions FIG. 10 shows the theoretical void volume value Vc (m ³⁾ obtained from the equation of the POC model shown in Table 1 above using the coefficients β _p and β _s obtained as described above. ) And the void amount experimental value Vt (m ³ ).
As shown in FIG. 10, the void amount theoretical value Vc obtained by the void amount equation (1) represents the void amount experimental value Vt with an accuracy within a range of approximately ± 1.5%.
In addition, FIG. 11 shows, for each coarse aggregate, mortar coarse aggregate void ratio coarse aggregate (Km) and void amount (m ³ ) (void amount experimental value) at each paste fine aggregate void ratio (Kp). The relationship between Vt and the theoretical void amount Vc) is shown.
From these results, the mortar coarse aggregate void ratio Km and the paste fine aggregate void ratio Kp affect the void volume of the porous concrete according to the void amount theoretical formula (formula (1)) obtained from the void model (POC model). It is considered that the impact can be quantitatively evaluated.

7). Next, the result of porous concrete using coarse aggregate (G1305A; particle size range 13 to 5 mm) and fine aggregate (SA; particle size range 5 to 0 mm) for air bubbles in porous concrete The analysis was performed using.
As shown in Table 7 above, since the air volume ratio Am (air volume) of the mortar at the paste fine aggregate gap ratio Kp = 5 is 0.051, the air of the porous concrete is obtained from the formula of Table 2. The quantities Va (m ³ ) and Kmx (the mortar coarse aggregate void ratio that is the boundary value between porous concrete and ordinary concrete) are determined.
FIG. 12 shows an example of the result in consideration of air bubbles. FIG. 12 shows the relationship between the mortar coarse aggregate void ratio (Km) and the void amount or air amount (m ³ ) when the paste fine aggregate void ratio Kp = 5. Moreover, in FIG. 12, the calculation result of Kmx (The mortar coarse aggregate space | gap ratio used as the boundary value of porous concrete and normal concrete) is shown.
In FIG. 12, Vt is a void amount experimental value, Vc is a void amount theoretical value, and Va is an air amount of porous concrete.
As described above, it is considered that the limit of porous concrete (Kmx; mortar coarse aggregate void ratio which is the boundary value between porous concrete and ordinary concrete) can be quantitatively evaluated by theoretically determining the void volume and air volume. It is done.

8). Evaluation of suitability of theoretical formula of void amount Next, an attempt was made to quantitatively evaluate the influence of the materials used and the blending conditions on the void amount using the theoretical formula of the void amount (formula (1)).
Effect of coarse particle ratio of fine aggregate Table 10 shows the physical property values of the aggregate used in the evaluation of suitability in this section. As the coarse aggregate, two types of aggregates having a particle size range of 13 to 5 mm (No. 6 crushed stone; G1305C, G1305D) were used. As the fine aggregate, land sand (SD) used for ordinary concrete and fine sand (SE) having a fine particle size were used. As the cement (binding material), ordinary Portland cement (density: 3.16 g / cm ³ ) was used. As the admixture / admixture, an inorganic admixture exclusively for porous concrete for road pavement (Ad1, density; 2.26 g / cm ³ ) was used.
Table 11 shows combinations of coarse aggregate and fine aggregate as the blending level of porous concrete. FIG. 13 shows the relationship between the mortar coarse aggregate gap ratio Km and the paste fine aggregate gap ratio Kp in each combination of coarse aggregate and fine aggregate.
The pore volume theoretical value Vc of porous concrete using land sand (SD) as fine aggregate is a coefficient β _p using the same admixture (Ad1) and coarse aggregate (G1305B) in the same particle size range (13 to 5 mm). (Β _p = 0.1314) and coefficient β _s (β _s = 0.5199) were used for calculation (see Table 9).
Further, the pore volume theoretical value Vc of the porous concrete using fine sand (SE) as the fine aggregate is different in the particle size range of the fine aggregate. Therefore, first, “5. Calculation of the coefficients β _p and β _s ” described above. The coefficient β _p (β _p = 0.1777) and the coefficient β _s (β _s = 0.1853) are calculated in the same manner as described above, and then the voids of the porous concrete are calculated using the coefficients β _p and β _s. The theoretical amount Vc was calculated.
FIG. 14 shows the relationship between the void amount theoretical value Vc (m ³ ) and the void amount experimental value Vt (m ³ ) in the combination of each coarse aggregate and fine aggregate. As shown in FIG. 14, the void amount theoretical value Vc obtained by the equation (1) indicates the void amount experimental value Vt with high accuracy within a range of approximately ± 1.5%. From this, it is considered that the same values may be used for β _s and β _p if the blending conditions of the mortar part and the aggregates used are substantially the same.
In the case of using a small particle size fine aggregate (fine sand; SE), the coefficient β _s decreased. However, since the fine aggregate particles existing between the coarse aggregate particles become small, the coarse aggregate This is probably because the mortar thickness to be coated becomes small.

Effect of Coarse Aggregate Particle Size Table 12 shows the physical property values of the aggregates used in the suitability evaluation in this section. As the coarse aggregate, five types (G2013E, G1305E, G1308E, G0805E, G0502E) with different particle sizes produced from the same production area were used, and fine sand (SF) having a fine particle size was used. As the cement (binding material), ordinary Portland cement (density: 3.16 g / cm ³ ) was used. As the admixture / admixture, a special admixture for porous concrete for products (Ad3, density: 2.65 g / cm ³ ) was used.
Table 13 shows the composition of the porous concrete.

  About the porous concrete of the mixing | blending shown in Table 13, in the following formula | equation (31) derived | led-out from said formula (1), the actual volume ratio Gg of a coarse aggregate, the mortar coarse aggregate void ratio Km, and a void amount experimental value By assigning Vt, the ratio β of the mortar covering the coarse aggregate was calculated for each coarse aggregate.

FIG. 15 shows the relationship between the coarse aggregate average particle diameter (mm) and the ratio β of the mortar covering the coarse aggregate. In FIG. 15, porous concrete (three types) each using the three types of fine aggregates (SA, SB, SC) of “5. Calculation of coefficients β _p and β _s ” above and “8” .Evaluation of suitability of theoretical formula for void volume (1) Effect of coarse aggregate ratio of fine aggregate “Porosity concrete using fine aggregate (SE) has a paste fine aggregate void ratio Kp of 3.92 ( Β (the ratio of the mortar covering the coarse aggregate) that gives Kp = 3.92) is also shown.
As shown in FIG. 15, the relationship between the coarse aggregate average particle size and β (ratio of the mortar covering the coarse aggregate) deviated depending on the fine aggregate particle size. The reason for this is that when the fine aggregate is uniformly present between the coarse aggregates and the distance between the coarse aggregate particles is affected by the fine aggregate particle size, there are many contacts when the coarse aggregate particle size becomes small. Thus, the ratio β of the mortar covering the coarse aggregate is increased. However, if the surface area of the coarse aggregate is increased, the mortar coating thickness before compaction is considered to be small and easy to tighten, the distance between the coarse aggregate particles is reduced, and the ratio of the mortar covering the coarse aggregate β Decrease.
Therefore, the relationship between the coarse aggregate average particle size and the ratio β of the mortar covering the coarse aggregate is considered to be different depending on the fine aggregate particle size and mortar fluidity.

9. Proposal of blending design method for porous concrete having required voids Next, a blending design method for obtaining porous concrete having a design void amount is proposed.
Main blending conditions are determined by the design void amount Vd, water binder ratio W / B (or water cement ratio W / C), mortar coarse aggregate void ratio Km, and paste fine aggregate void ratio Kp. The mortar coarse aggregate void ratio Km is calculated from the following equation (32) using the design void amount Vd, the actual volume ratio Gg of the coarse aggregate, and the coefficient β (ratio of mortar covering the coarse aggregate) from the POC model. Can be sought.

Here, the coefficient β is obtained from the paste fine aggregate gap ratio Kp, the coefficients β _s and β _p , and the coefficients β _s and β _p are values determined by experiments. The coefficients β, β _s and β _p can be set with reference to the above-described results (for example, Table 8, Table 9, etc.). The paste fine aggregate void ratio needs to be determined from the viewpoints of preventing dripping of the mortar, reducing drying shrinkage, and improving durability.

(1) Formulation calculation example Using the materials shown in Table 14, the water cement ratio W / C is 20%, the admixture addition amount is C × 1% (1% with respect to the unit cement amount (kg)), An example of blending calculation of porous concrete when the design void amount Vd is 0.175 m ³ and the paste fine aggregate void ratio Kp is 7.0 is shown.
The coefficients β _p and β _s when 13-5 mm coarse aggregate (No. 6 crushed stone) and fine aggregate for concrete are used are β _p = −0.0057, β _s = 0. Since it is 5387, β = 0.1065 is calculated from the above equation (2). The mortar coarse aggregate void ratio Km at which the designed void amount Vd is 0.175 m ³ is calculated as 0.68 by the above equation (32). Table 15 shows the formula composition calculated from this value.

(2) Blending correction method When the void amount experimental value deviates from the theoretical void amount, it is necessary to correct the blending. When conditions other than the mortar coarse aggregate void ratio Km are made equal, the coefficient β (ratio of mortar covering the coarse aggregate) is recalculated to correct the mortar coarse aggregate void ratio Km.
For example, in the above-described composition, when the void amount experimental value is measured as 0.200 m ³ , the coefficient β (the ratio of the mortar covering the coarse aggregate) recalculated from the above equation (31) is 0. 1711. The formula can be corrected by correcting Km to 0.77 and recalculating the formula according to the above equation (32).

10. Summary The present invention devised a theoretical model (POC model) that focuses on the filling properties of the mortar covering state on the coarse aggregate in porous concrete, and considers the physical properties of the materials used, and a method for blending and designing porous concrete Is built.
The contents are as follows.
(1) A theoretical model (POC model) focusing on filling properties based on the ratio of mortar in porous concrete covering coarse aggregate was devised. By this model, the void structure based on the material composition is formulated, the actual volume ratio (Gg) of coarse aggregate, the actual volume ratio (Gs) of fine aggregate, the mortar coarse aggregate void ratio Km, the paste fine aggregate void The void amount theoretical formula (formula (1)) using the ratio Kp and the ratio β at which the mortar covers the coarse aggregate was constructed.
(2) Experimental verification of the void amount theoretical formula (formula (1)) is performed, and the void amount theoretical value (Vc) is a high accuracy within the range of ± 1.5% of the void amount experimental value (Vt). It was confirmed that the effects of the material properties and blending conditions on the void volume of porous concrete can be quantitatively evaluated.
(3) A concrete conceptual diagram using a mortar coarse aggregate void ratio and a paste fine aggregate void ratio was created by examining voids and air bubbles in porous concrete. As a result, the areas of ordinary concrete and porous concrete were clarified, and it was shown that porous concrete is “concrete having voids between aggregate particles excluding air bubbles such as entrapped air and entrained air”.
(4) A blending design method for porous concrete having a required void amount was proposed using the designed void amount, the physical properties of the materials used, and the void amount theoretical formula.

It is explanatory drawing which shows the model (POC model) which modeled porous concrete. (A) is explanatory drawing which shows a coarse aggregate covering state, (b) It is explanatory drawing which shows a space | gap filling state. It is explanatory drawing which shows a POC model. It is a figure which shows the relationship between the POC model and the mortar coarse aggregate space ratio Km in each limit state (coarse aggregate covering state and void filling state) and the void amount Vc of porous concrete. It is a figure which shows the relationship between the mortar coarse aggregate void ratio Km, the void amount Vc (m ³ ) of porous concrete, the air amount Va (m ³ ), and the air amount Ac (m ³ ) of ordinary concrete. It is a conceptual diagram of the concrete represented by the relationship between the mortar coarse aggregate void ratio Km and the paste fine aggregate void ratio Kp. It is explanatory drawing which showed the measuring method of the void amount of the porous concrete by a settlement method. (A) to (e) are mortar coarse aggregate void ratio Km, void amount (m ³ ) (regression value (theoretical value of void amount) and void) in each paste fine aggregate void ratio Kp of each coarse aggregate. It is a figure which shows the relationship with quantity experiment value. It is a figure which shows the relationship between coefficient (beta) _p and (beta) _s, and a coarse aggregate average particle diameter. A void volume theoretical value Vc ^{(m 3),} is a graph showing the relationship between the void volume experimental value Vt ^{(m 3).} (A) to (e) are mortar coarse aggregate void ratio coarse aggregate (Km) and void amount (m ³ ) (void) in each paste fine aggregate void ratio (Kp). It is a figure which shows the relationship with quantity experiment value Vt and void | hole amount theoretical value Vc). In the paste fine aggregate void ratio Kp = 5, a diagram illustrating the mortar coarse aggregate void ratio (Km), the relationship between the void volume or air volume (m ^3). It is a figure which shows the relationship between the mortar coarse aggregate space | gap ratio Km and the paste fine aggregate space | gap ratio Kp in the combination of each coarse aggregate and fine aggregate. In combination with the coarse aggregate and fine aggregate, which is a diagram showing the relationship between the void volume theory Vc and (m ³⁾ and the void volume experimental value Vt (m ^3). It is a figure which shows the relationship between a coarse aggregate average particle diameter (mm) and the ratio (beta) of the mortar which coat | covers a coarse aggregate.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Porous concrete 2 Coarse aggregate 3 Mortar 3a The mortar of the part which coat | covers a coarse aggregate uniformly 3b The mortar of the part which partially fills the space | gap between coarse aggregate particles 4 Cavity 5 Vibration table 6 Formwork 7 Sample 8 Weight Ac Normal concrete air volume (m ³ )
Ad unit admixture amount (kg)
Am Volume ratio of mortar air volume Ap Volume ratio of air volume of paste B Unit amount of binder (kg)
C Unit cement amount (kg)
g Unit coarse aggregate volume (m ³ )
g _l Unit volume of coarse aggregate in void filling state (m ³ )
g _u Coarse aggregate volume covered with coarse aggregate (m ³ )
G Unit coarse aggregate amount (kg)
Gg Actual volume ratio of coarse aggregate Gs Actual volume ratio of fine aggregate Km Mortar coarse aggregate void ratio (Km> 0)
Void volume Kmx in concrete 0 m ³ and comprising mortar coarse aggregate void ratio Kp paste fine aggregate void ratio (Kp> 0)
Paste fine aggregate void ratio at which the void amount in Kpx mortar becomes 0 m ³ Upper limit value of paste fine aggregate void ratio in Kp _lim void amount formula m Unit mortar volume (m ³ )
m _l Unit volume of mortar filled with voids (m ³ )
m _u units mortar volume of coarse aggregate covering state ^(m 3)
p Unit paste volume (m ³ )
Qg Water Absorption Rate of Coarse Aggregate Rg Unit Coarse Aggregate Bulk Volume Rg _l Unit Coarse Aggregate Bulk Volume Filled with Gap Rg _u Unit Coarse Aggregate Bulk Volume Coated with Coarse Aggregate s Unit Fine Aggregate Volume (m ³ )
S Amount of fine aggregate (kg)
T Theoretical unit volume mass of porous concrete calculated without air bubbles and voids (kg / m ³ )
Tg Unit volume mass of coarse aggregate (kg / m ³ )
Tg ′ Unit volume mass of coarse aggregate in the dry state (kg / m ³ )
V Bulk volume of porous concrete in void volume measurement test (m ³ )
Va Porous concrete air volume (m ³ )
Vc Theoretical void volume of porous concrete (m ³ )
Vc _l Void volume of porous concrete (m ³ )
Void volume porous concrete vc _u coarse aggregate covering state _(m 3)
Design void volume porous concrete obtained from the design void volume Vd 'blending Vd porous concrete (= Vc _l, ^m 3)
Vg Unit volume of coarse intergranular particle gap (m ³ )
Vs Unit volume of voids between fine aggregate particles (m ³ )
Experimental value of void volume of Vt porous concrete (m ³ )
W Unit water volume (kg)
Wtp Mass of sample in void volume measurement test (kg)
ratio of the unit amount of mortar evenly coat the coarse aggregate per unit mortar amount of beta in concrete ^{1m 3 (0 ≦ β ≦ 1} )
β Coefficient indicating the degree of influence of the volume ratio of the paste constituting the mortar in _p 1 m ³ on β β coefficient indicating the degree of influence of the volume ratio of the fine aggregate constituting the mortar in β _s concrete 1 m ³ on β ρg Surface dry density of coarse aggregate (kg / m ³ )

Claims (2)

A porous concrete blending design method characterized by performing blending design using the following equation (1) so as to obtain the void amount after determining a target void amount.

(In Formula (1), Vc is the void volume (m ³ ) of porous concrete, Gg is the actual volume ratio (%) of coarse aggregate, Km is the mortar coarse aggregate void ratio, and β is porous. (This is the mass ratio of the amount of mortar that covers the entire surface of the coarse aggregate with a uniform thickness to the total amount of mortar in the unit volume of concrete.) The method for blending and designing porous concrete according to claim 1, wherein β in the formula (1) is represented by the following formula (2).

(In the formula (2), β is the mass ratio of the mortar amount covering the entire surface of the coarse aggregate with a uniform thickness to the total mortar amount in the unit volume of the porous concrete, and β _p is the mortar in the porous concrete. The constituent paste is a coefficient indicating the degree of influence on β, β _s is a coefficient indicating the degree of influence of the fine aggregate constituting the mortar in the porous concrete on β, and Gs is the fine aggregate. (The actual volume ratio (%) of K, and Kp is the paste fine aggregate void ratio.)

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