JP6464417B2 - Method for manufacturing cast-in-place porous concrete - Google Patents

Description

The present invention relates to a method for producing a cast-in-place porous concrete that manages a specific fresh property, and particularly relates to a method for producing a cast-in-place porous concrete suitable for use in sidewalks and parking lots.
In-situ porous concrete refers to porous concrete that is produced by mixing and transporting porous concrete manufactured at a ready-mixed concrete plant with an agitator vehicle, etc., and then placing and constructing at the site. It was manufactured at the factory as a secondary product. Different from porous concrete blocks.

In recent years, on-site porous concrete excellent in water permeability and workability has been put into practical use. And in order to manufacture on-site porous concrete excellent in water permeability, workability, and durability, it is necessary to manage its fresh properties.
Methods for managing porous concrete according to its fresh properties include methods for evaluating the compaction properties of porous concrete such as the settlement method (Non-patent Document 1) and the Marshall method (Non-patent Document 2), cement paste and mortar There is a method for evaluating the properties of binder components contained in porous concrete, such as fluidity (Non-patent Document 3) and the amount of cement paste dropped (Non-Patent Document 4).
Of these, as shown in FIG. 1, the settlement method measures the volume of concrete sinking by vibrating a steel formwork filled with porous concrete (POC in the figure) on a vibration table (table vibrator). This is a method for obtaining the porosity (void index value). The Marshall method is a method of evaluating the consistency of porous concrete by squeezing 50 times on one side with a Marshall randomer.
However, because the subsidence method and the Marshall method do not sufficiently reproduce the vibration status during construction of cast-in-place porous concrete, the surface is easily peeled off or the permeability coefficient is extremely low by these evaluations alone. There is a risk that non-practical cast-in-place porous concrete will be produced.

Jiro Watanabe et al., “Study on Consistency of Permeable and Drainable Concrete for Pavement”, Papers on Cement and Concrete, No. 52, 798-803, 1998 Osamu Sekiguchi et al., “Application of Porous Concrete to Sidewalks and Roadways”, Pavement, Vol. 36, no. 4, pp. 16-21, April 2001 Yukihisa Yuasa et al., “Fundamental research on manufacturing method of porous concrete”, Annual report on concrete engineering, Vol. 21, pp. 235-240, 1999 Katahira Hiroshi et al., "Examination of Fresh Properties Judgment Method for Porous Concrete", Civil Engineering Technical Data, 41-9, pp. 56-61, 1999

  Accordingly, the present invention is a method for solving the above-mentioned problems, and provides a method for producing a cast-in-place porous concrete excellent in water permeability, workability, and durability by managing specific fresh properties. Objective.

The present inventors have found that the above problems can be solved by managing the porosity, non-vibration porosity, and mortar flow rate as the fresh properties of in-situ porous concrete, and have completed the present invention. That is, the present invention is as follows.
[1] In the production of cast-in-place porous concrete containing Portland cement, fine aggregate, coarse aggregate, water, and high-performance AE water reducing agent,
The porosity calculated by the method of the following (A) is 20-25 volume%,
The fresh properties are controlled so that the vibration-free porosity calculated by the method (B) below is 37% by volume or less and the mortar flow rate calculated by the method (C) is 35% by volume or less. A method for producing a cast-in-place porous concrete, characterized by producing.
(A) Porosity calculation method: An iron plate having a diameter of 99 mm and a thickness of 1 mm is placed on porous concrete packed in a steel mold having an inner diameter of 100 mm and a height of 200 mm, and a weight of 4 kg is further provided on the plate. The weight of the porous concrete after the vibration (Vb) after placing the weight and exciting it for 120 seconds at a frequency satisfying the following Fa using a wall strike vibrator having a weight of 5.9 kg from above the weight. Based on the above, a method for calculating the porosity using the following formula (1) Fa: 99 mm in diameter and thickness on porous concrete having the following composition A packed in a steel mold having an inner diameter of 100 mm and a height of 200 mm Place a 1 mm iron plate, place a weight of 4 kg on the plate, and vibrate for 120 seconds from above the weight using a wall strike vibrator with a weight of 5.9 kg. Using the following formula (1) The frequency at which the porosity of the porous concrete having the following composition A calculated is in the range of 21.4 to 22.5% by volume. (B) Non-vibration porosity calculation method: on steel mold having an inner diameter of 100 mm and a height of 200 mm An iron plate with a diameter of 99 mm and a thickness of 1 mm is placed on the stuffed porous concrete, and a weight of 4 kg is further placed on the iron plate. When the settlement due to the loading of the iron plate and the weight stops, Method of calculating no-vibration porosity from volume (Vw) using the following formula (2) (C) Mortar flow rate calculation method: diameter on porous concrete packed in a sieve having a nominal aperture of 2.36 mm Place a decorative plywood sieve cover with a thickness of 200 mm and a thickness of 15 mm, and vibrate at a frequency satisfying the following Fc condition using a wall strike vibrator weighing 5.9 kg from above the sieve cover. A method of calculating the mortar flow rate using the following equation (3) based on the volume (Vf) of the mortar that has flowed down after 120 seconds from the start of vibration. Fc: Packed on a sieve having a nominal opening of 2.36 mm On the porous concrete of the following composition A, a sieve cover made of decorative plywood having a diameter of 200 mm and a thickness of 15 mm was placed, and a wall strike vibrator weighing 5.9 kg was used for 120 seconds from above the sieve cover. Based on the volume (Vf) of the mortar that was vibrated and flowed until the end of the vibration, the mortar flow rate of the porous concrete of the following composition A calculated using the following formula (3) is 0.2-2. Frequency in the range of 3% by volume Porosity (% by volume) = 100−W / (Vb × T) × 100 (1)
Non-vibration porosity (volume%) = 100−W / (Vw × T) × 100 (2)
Mortar flow rate (% by volume) = 100 × Vf / Vo (3)
(Wherein, W represents the mass of the porous concrete charged into the mold, Vb represents the volume of the porous concrete after vibration, and T represents the unit of blending the porous concrete calculated with the porosity being 0% by volume. It represents the volume mass, Vw represents the volume of the porous concrete when the settlement due to the loading of the weight is stopped, Vf represents the volume of the mortar that has flowed down by the vibration, and Vo represents the volume of the mortar in the porous concrete before the vibration. Represents.)
[Composition A]

[2] Portland cement unit amount 130~500kg / ^{m 3,} the unit amount of fine aggregate is 40~300kg / ^{m 3,} the unit amount of coarse aggregate is 1100~1900kg / ^{m 3,} the unit amount of water is 40 ~150kg / ^{m 3,} and the unit amount of high AE water reducing agent is 0.7~15.0kg / ^{m 3,} the production method of cast-in-place porous concrete according to [1].
[3] The method for producing on-site porous concrete according to [2], wherein the unit amount of the thickener is 0.5 kg / m ³ or less.
[4] The method for producing in-situ porous concrete according to [2] or [3], wherein the unit amount of the inorganic admixture is 15 kg / m ³ or less.

  The method for producing in-situ porous concrete of the present invention can produce in-situ porous concrete excellent in water permeability, workability, and durability. Moreover, in the manufacturing method of on-site porous concrete of this invention, when using a thickener, the quality fluctuation | variation of on-site porous concrete for every place (position) by an on-site construction, every production batch, and every construction can be made small. Furthermore, in the method for producing on-site porous concrete according to the present invention, when an inorganic admixture is used, workability such as paving work using on-site porous concrete is improved.

It is the schematic of a settlement method. It is a figure which shows an example of the porosity calculation method. It is a figure which shows an example of the vibrationless porosity calculation method. It is a figure which shows an example of the mortar falling rate calculation method. It is the schematic of the in-situ porous concrete used in order to measure an in-situ water permeability (water permeability obtained by the in-situ permeability test). The on-site water permeability was measured at the position of ○ in the figure.

  The present invention calculates (A) porosity calculated by the porosity calculation method, (B) non-oscillation porosity calculated by the non-oscillation porosity calculation method, and (C) mortar flow rate calculation method. This is a method for producing on-site porous concrete by managing the fresh properties of on-site porous concrete based on the mortar flow rate. Hereafter, each said method etc. are demonstrated in detail using figures.

(A) Porosity Calculation Method As shown in FIG. 2, the porosity is calculated by placing a plate 3 on a predetermined amount of porous concrete 2 packed in a mold 1 and further placing a weight 4 on the plate 3. 4 is vibrated for 120 seconds using a wall striking vibrator, and based on the volume of the porous concrete after the vibration, calculation is performed using the equation (1).
The mold 1 and the plate 3 are not particularly limited. However, the mold 1 is preferably a steel mold, and the plate 3 is preferably an iron plate because it is difficult to deform due to vibration. Moreover, since the said vibrator can reproduce the vibration condition at the time of construction, a wall hitting vibrator (a trowel type vibrator) is suitable.
The volume (Vb) of the porous concrete after the vibration is, for example, the length from the upper surface of the mold frame to the upper surface of the porous concrete after the vibration using a mold with a known inner diameter and inner height. It can be obtained by measuring with a depth gauge or the like, obtaining the height of the porous concrete after vibration from the difference between the height of the mold and this length, and multiplying this height by the cross-sectional area inside the mold.
And the porosity of porous concrete is 20-25 volume%, More preferably, it exceeds 20 volume% and is 25 volume%.

(B) Non-Vibration Porosity Calculation Method As shown in FIG. 3, the non-vibration void ratio is calculated by placing a plate 3 on a predetermined amount of porous concrete 2 packed in a mold 1 and further placing a weight 4 on the plate 3. Is calculated using the above formula (2) based on the volume of the porous concrete at the time when the settlement due to the loading stops. The non-vibration porosity is different from the porosity and is a porosity determined without vibration.
Moreover, the volume (Vw) of the porous concrete after loading of the weight is, for example, when the settlement of the porous concrete due to loading stops from the upper surface of the mold using a mold having a known inner diameter and inner height ( Usually, the length to the upper surface of the porous concrete at about 2 seconds after loading) is measured with a depth gauge etc., and the height of the porous concrete is obtained from the difference between the height of the formwork and this length, and the mold is measured at this height. It can be obtained by multiplying the cross-sectional area inside the frame.
The non-vibration porosity is an index for mainly evaluating the consistency of mortar in porous concrete. The larger the value of the index, the more difficult it is to compact the in-situ permeable concrete, and the hardened concrete surface becomes easier to peel off.
Therefore, the non-vibrating porosity of the porous concrete is 37% by volume or less.

(C) Method for calculating mortar flow rate The mortar flow rate is calculated by placing a sieve lid 6 on the porous concrete 2 packed in the sieve 5 and using a wall hammering vibrator on the sieve lid 6 as shown in FIG. Based on the volume of the mortar that has flowed down and 120 seconds have passed after the start of vibration, calculation is performed using Equation (3). In addition, the sieve cover 6 is not specifically limited, A decorative plywood, an iron plate, a resin board, etc. are mentioned.
The mortar flow rate is an index for evaluating the properties of the cured porous concrete, and the larger the value, the smaller the hydraulic conductivity of the cured porous concrete.
Therefore, the mortar flow rate of porous concrete is 35% by volume or less.
In the present invention, the porosity, vibrationless porosity, and mortar flow rate are measured before construction of porous concrete, preferably within about 30 minutes before construction.
In the present invention, the porosity, non-vibration porosity, and mortar flow rate may be measured for each production batch of porous concrete, or a single work (for example, 2 to 4 batches may be agitator). You may measure using the mixture mixed with the car.

(D) On-site porous concrete Next, on-site porous concrete will be described.
As described above, the in-situ porous concrete produced according to the present invention includes (1) Portland cement, (2) fine aggregate, coarse aggregate, water, and (3) high-performance AE water reducing agent as essential constituent materials. And (4) a thickener and (5) an inorganic admixture as optional constituent materials. Hereinafter, each constituent material will be described.

(1) Portland cement The Portland cement is not particularly limited. For example, various Portland cements such as ordinary Portland cement, early-strength Portland cement, moderately hot Portland cement, and low heat Portland cement can be used. Among these, from the viewpoint of strength development and cost, Portland cement is preferably ordinary Portland cement and early-strength Portland cement.

(2) Fine aggregate, coarse aggregate, water As the fine aggregate, river sand, land sand, sea sand, quartz sand, crushed sand and the like can be used. Further, as the coarse aggregate, river gravel, sea gravel, crushed stone and the like can be used. Among these, from the viewpoint of strength development and cost, the coarse aggregate is preferably crushed stone No. 7. Moreover, tap water etc. can be used for water.

(3) High-performance AE water reducing agent As the high-performance AE water reducing agent, a polycarboxylic acid compound and a naphthalenesulfonic acid formaldehyde condensate salt can be used.

(4) Thickening agent Moreover, the cast-in-place porous concrete manufactured by this invention, Preferably, a thickening agent can be included as arbitrary constituent materials. Porous concrete containing a thickener is less susceptible to quality fluctuations at each location (position), every manufacturing batch, and every construction.
The thickener is, for example, one or more selected from cellulose thickeners such as methylcellulose, hydroxypropylmethylcellulose, and hydroxyethylmethylcellulose, and acrylic thickeners such as acrylamide homopolymer and acrylamide copolymer. Is mentioned. Among these thickeners, the cellulosic thickener is preferable because the variation in quality of the porous concrete becomes smaller.

(5) Inorganic admixture The in-situ porous concrete produced according to the present invention can preferably further include an inorganic admixture as an optional constituent material. Below, each component contained in this inorganic type admixture is demonstrated.
(I) Pozzolanic fine powder Pozzolanic fine powder is not a hydraulic substance by itself, but with calcium hydroxide, it is a substance that reacts in water to form an insoluble gel and hardens.
Examples of the pozzolanic fine powder include silica fume, silica dust, fly ash, slag, volcanic ash, silica sol, and precipitated silica. Among these, silica fume and silica dust are preferable because their average particle diameter is 1 μm or less and they do not need to be pulverized. When the pozzolanic substance is pulverized, a ball mill, a rod mill, or the like can be used as a pulverizing means.
The BET specific surface area of the pozzolanic fine powder is preferably 15 to 25 m ² / g, more preferably 17 to 23 m ² / g, and still more preferably 18 to 22 m ² / g. If the specific surface area is out of the range of 15 to 25 m ² / g, the water permeability may be reduced and the workability at the time of placing may be lowered.

(Ii) Blast Furnace Slag Powder As the blast furnace slag powder, in addition to the blast furnace slag fine powder for concrete specified in JIS A 6206, a powder obtained by further pulverizing the fine powder is used.
Fineness of blast furnace slag powder is a Blaine specific surface area, preferably 4000~12000cm ² / g, more preferably 5000~10000cm ² / g. If the specific surface area is less than 4000 cm ² / g, the latent hydraulic property is low, and if it exceeds 12000 cm ² / g, the labor of pulverization increases and the cost increases. Moreover, a ball mill, a rod mill, etc. can be used as a grinding | pulverization means.

(Iii) Anhydrous gypsum The anhydrous gypsum includes natural anhydrous gypsum and regenerated anhydrous gypsum obtained by heat treatment of gypsum waste such as gypsum board.
Further, the powder of the anhydrite is the Blaine specific surface area, preferably 3000~12000cm ² / g, more preferably 4000~10000cm ² / g. When the specific surface area is less than 3000 cm ² / g, the strength development of the cured product is low, and when it exceeds 12000 cm ² / g, the labor of pulverization increases and the cost increases.

(6) Blending of cast-in-place porous concrete Next, blending of cast-in-place porous concrete will be described.
The composition of the cast-in-place porous concrete is such that the unit amount of Portland cement is 130 to 500 kg / m ³ , the unit amount of fine aggregate is 40 to 300 kg / m ³ , the unit amount of coarse aggregate is 1100 to 1900 kg / m ³ , The unit amount of water is 40 to 150 kg / m ³ , and the unit amount of the high performance AE water reducing agent is 0.7 to 15.0 kg / m ³ . If the composition of the constituent materials is within the above range, on-site porous concrete having high water permeability and excellent workability can be produced.
Moreover, when the said cast-in-place porous concrete contains a thickener as an arbitrary component, the unit amount of this thickener is 0.5 kg / m < ³ > or less. When the value exceeds 0.5 kg / m ³ , it becomes difficult to make the non-vibration porosity to 37% by volume or less. The unit amount of the thickener is preferably 0.05 to 0.4 kg / m ³ , more preferably 0.1 to 0.2 kg / m ³ .

Further, when the thickening agent is not included, the blending of the in-situ porous concrete preferably has a unit amount of 240 to 400 kg / m ^{3 of} Portland cement, a unit amount of fine aggregate of 140 to 250 kg / m ³ , The aggregate unit amount is 1100 to 1400 kg / m ³ , the water unit amount is 70 to 120 kg / m ³ , and the high-performance AE water reducing agent unit amount is 0.7 to 8.0 kg / m ³ , and the viscosity is increased. When the agent is included, preferably, the unit amount of Portland cement is 240 to 500 kg / m ³ , the unit amount of fine aggregate is 90 to 250 kg / m ³ , the unit amount of coarse aggregate is 1100 to 1400 kg / m ³ , water The unit amount is 70 to 150 kg / m ³ , and the unit amount of the high-performance AE water reducing agent is 1.0 to 15.0 kg / m ³ .

Moreover, when the said spot cast porous concrete contains the inorganic type admixture which contains as an arbitrary component, the unit amount of this inorganic type admixture is 15 kg / m < ³ > or less. When the value is within the range, workability such as paving work is improved. The unit amount of the inorganic admixture is preferably 0.5 to 10 kg / m ³ , more preferably 1 to 5 kg / m ³ .
Here, the unit amount of the constituent material means the mass of the constituent material contained per 1 m ^{3 of} concrete.
In addition, the porous concrete concerning this invention can contain 0.02 mass part or less of air quantity adjusting agents with respect to 100 mass parts of Portland cement besides the said material.
Furthermore, the porous concrete according to the present invention may contain a cement admixture such as quartz powder and limestone powder in addition to the above materials.

(7) Mortar coarse aggregate void ratio of cast-in-place porous concrete The mortar coarse aggregate void ratio of the porous concrete is preferably 0.4 to 0.8. The mortar coarse aggregate void ratio is one of the indexes representing the blending characteristics of the porous concrete, and represents the ratio of the volume of the mortar to the void amount between the coarse aggregates when the coarse aggregate is compacted.
Moreover, the paste fine aggregate void ratio of the porous concrete is preferably 5 to 11. The paste fine aggregate void ratio is also one of the indexes representing the blending characteristics of the porous concrete, and represents the ratio of the volume of the cement paste to the void amount between the fine aggregates in a state where the fine aggregate is compacted.
In the construction, it is preferable to use a vibratory asphalt finisher for leveling and compacting the porous concrete. Further, after the spreading and compaction, it is preferable to further perform compaction and flat finishing by using a rubber-wound vibration roller.

EXAMPLES Hereinafter, although an Example demonstrates this invention, this invention is not limited to these Examples.
1. Materials used, blending, and kneading method Table 1 shows the materials used and Table 2 shows the blending of porous concrete. SP in Table 1 is a polycarboxylic acid compound and corresponds to a high performance AE water reducing agent.
For kneading, a biaxial forced kneading mixer was used, and all the materials were put into the mixer at once and kneaded for 2 minutes. The temperature of the porous concrete immediately after kneading was 29 ° C.
18 m ^{3 of} each of the porous concretes of the examples and reference examples shown in Table 2 were produced. Specifically, for each of the porous concrete, 3 batches (the production amount of 1 batch is 1.5 m ³ ) were mixed with an agitator car, and the mixture (porous concrete, 4.5 m ³ ) was produced 4 times. .

2. Calculation of porosity According to the following procedures (1) to (5), the volume (Vb) of the porous concrete after vibration is obtained, and when 30 minutes have elapsed after kneading using this value and the above equation (1) The porosity of porous concrete (temperature 30 ° C.) was calculated. The results are shown in Table 3.
(1) Samples were collected uniformly and uniformly from the entire porous concrete prepared according to the formulation shown in Table 2, and 2.2 kg of Sample 2 was weighed.
(2) In a steel mold 1 having an inner diameter of 100 mm and an inner height of 200 mm, the sample 2 was divided into three layers, and the samples in each layer were packed flatly so as not to be unevenly distributed.
(3) An iron plate 3 having a diameter of 99 mm and a thickness of 1 mm was placed on the upper surface of the sample 2, and a 4 kg weight 4 was placed on the iron plate 3.
(4) A wall hitting vibrator having a weight of 5.9 kg was placed on the weight 4, and the weight 4 was vibrated uniformly for 120 seconds while being careful not to apply external force other than the weight and vibration of the vibrator.
(5) The length from the upper surface of the mold to the upper surface of the sample 2 after vibration is measured using a depth gauge, and the height of the sample 2 is obtained from the difference between the height inside the mold and this length. The volume (Vb) of the sample was obtained by multiplying the inner cross-sectional area of the steel mold 1 (circular, 7850 mm ² ).

3. Calculation of non-vibration porosity The volume (Vw) of the sample was determined according to the same procedure as in the above steps (1) to (5) except that no vibration was performed with a wall-pitched vibrator. The vibration-free porosity of the porous concrete at the time when 30 minutes have elapsed after kneading was calculated using the formula. The results are shown in Table 4.

4). Calculation of the mortar flow rate The volume (Vf) of the flowed mortar was measured according to the following procedures (a) to (e), and the mortar at the time when 30 minutes passed after kneading using the value and the above equation (3) The flow rate was calculated. The results are shown in Table 5.
(A) Samples were collected uniformly and uniformly from the entire porous concrete prepared in the same manner as (1), and 1.5 kg of Sample 2 was weighed.
(B) The sample 2 was flattened and packed on the sieve 5 having a nominal aperture of 2.36 mm so as not to be unevenly distributed.
(C) On the upper surface of the sample 2, a sieve cover 6 made of decorative plywood having a diameter of 200 mm and a thickness of 15 mm was placed.
(D) Place a wall strike vibrator with a weight of 5.9 kg on the sieve lid 6 and vibrate for 120 seconds evenly from above the sieve lid 6 while taking care not to apply external force other than the weight and vibration of the vibrator. did.
(E) The volume (Vf) of the mortar which flowed down was measured after the vibration.

In Examples 1 to 5, the porosity is 21.4 to 23.9% by volume, the non-vibration porosity is 32.4 to 36.3% by volume, and the mortar flow rate is 0 to 32.9% by volume. The target value is met. On the other hand, the porosity of the porous concrete of the reference example measured in the same manner is 24.2 to 25.0% by volume, the non-vibration porosity is 40.5 to 43.1% by volume, and the mortar flow rate is 0% by volume. The vibration-free porosity did not meet the target value.
Moreover, when the bending strength at the age of 7 days of the porous concretes of Examples 1 to 5 was measured in accordance with JIS A 1106 “Concrete bending strength test method”, the bending strength was as shown in Table 6. It was as high as 4.4 to 5.1 N / mm ² .
Further, the permeability coefficient of the porous concrete of Examples 1 to 5 was measured in accordance with JCI-SPO3 “Permeability Test Method for Porous Concrete (Draft)”. .16-0.18 cm / sec and excellent water permeability.

5. On-site construction and curing of porous concrete When 40 to 45 minutes have passed after mixing with the agitator vehicle, the porous concretes of Examples 1 to 5 and the reference example were respectively spread using a vibratory asphalt finisher. After compacting, it was finished by compacting with a rubber-wrapped vibration roller. Thereafter, a vinyl sheet was quickly laid on the surface of the porous concrete and cured until the age of 7 days to produce an in-situ porous concrete shown in FIG. The on-site porous concrete has a thickness of 10 cm.

6). Peeling of the surface layer of the porous concrete after curing In the cast-in-place porous concrete of Examples 1 to 5, no defects such as surface peeling were observed in all the mixtures produced four times.
As described above, by controlling the porosity, vibration-free porosity, and mortar flow rate as fresh properties of porous concrete, it is possible to produce on-site porous concrete excellent in water permeability, workability, and durability. did it.
On the other hand, with the porous concrete of the reference example, the surface easily peeled off at 7 days of age and was difficult to actually use.

7). Quality fluctuation of cast-in-place porous concrete with and without thickener The quality fluctuation was evaluated using the fluctuation of water permeability as an index. Specifically, in the in-situ porous concrete of FIG. 5 using the manufactured Examples 1 to 5, the center (center) positions C1 to C8 and the out (outside) positions O1 to O8 of the in-situ porous concrete. The water permeability was measured in accordance with the “S025 Field Water Permeability Test Method” of the Japan Road Association, and the standard deviation of the field water permeability was determined. The results are shown in Table 8.

  As can be seen from Table 8, the in-situ porous concrete of Example 2, Example 4 and Example 5 containing the thickener has an in-situ water permeability compared to the in-situ porous concrete of Example 1 and Example 3. Small variation (standard deviation). Therefore, it can be said that the method for producing on-site porous concrete according to the present invention containing a thickener has a small quality fluctuation for each place (position) due to on-site construction. Moreover, it can be said that the quality fluctuation | variation for every manufacturing batch and every construction is also small from these data.

1 Formwork 2 Porous concrete (sample)
3 Plate 4 Weight 5 Sieve 6 Sieve lid 7 Sieve pan 8 Flowing mortar

Claims (4)

In the production of on-site porous concrete containing Portland cement, fine aggregate, coarse aggregate, water, and high performance AE water reducing agent,
The porosity calculated by the method of the following (A) is 20-25 volume%,
The fresh properties are controlled so that the vibration-free porosity calculated by the method (B) below is 37% by volume or less and the mortar flow rate calculated by the method (C) is 35% by volume or less. A method for producing a cast-in-place porous concrete, characterized by producing.
(A) Porosity calculation method: An iron plate having a diameter of 99 mm and a thickness of 1 mm is placed on porous concrete packed in a steel mold having an inner diameter of 100 mm and a height of 200 mm, and a weight of 4 kg is further provided on the plate. The weight of the porous concrete after the vibration (Vb) after placing the weight and exciting it for 120 seconds at a frequency satisfying the following Fa using a wall strike vibrator having a weight of 5.9 kg from above the weight. Based on the above, a method for calculating the porosity using the following formula (1) Fa: 99 mm in diameter and thickness on porous concrete having the following composition A packed in a steel mold having an inner diameter of 100 mm and a height of 200 mm Place a 1 mm iron plate, place a weight of 4 kg on the plate, and vibrate for 120 seconds from above the weight using a wall strike vibrator with a weight of 5.9 kg. Using the following formula (1) The frequency at which the porosity of the porous concrete having the following composition A calculated is in the range of 21.4 to 22.5% by volume. (B) Non-vibration porosity calculation method: on steel mold having an inner diameter of 100 mm and a height of 200 mm An iron plate with a diameter of 99 mm and a thickness of 1 mm is placed on the stuffed porous concrete, and a weight of 4 kg is further placed on the iron plate. When the settlement due to the loading of the iron plate and the weight stops, Method of calculating no-vibration porosity from volume (Vw) using the following formula (2) (C) Mortar flow rate calculation method: diameter on porous concrete packed in a sieve having a nominal aperture of 2.36 mm Place a decorative plywood sieve cover with a thickness of 200 mm and a thickness of 15 mm, and vibrate at a frequency satisfying the following Fc condition using a wall strike vibrator weighing 5.9 kg from above the sieve cover. A method of calculating the mortar flow rate using the following equation (3) based on the volume (Vf) of the mortar that has flowed down after 120 seconds from the start of vibration. Fc: Packed on a sieve having a nominal opening of 2.36 mm On the porous concrete of the following composition A, a sieve cover made of decorative plywood having a diameter of 200 mm and a thickness of 15 mm was placed, and a wall strike vibrator weighing 5.9 kg was used for 120 seconds from above the sieve cover. Based on the volume (Vf) of the mortar that was vibrated and flowed until the end of the vibration, the mortar flow rate of the porous concrete of the following composition A calculated using the following formula (3) is 0.2-2. Frequency in the range of 3% by volume Porosity (% by volume) = 100−W / (Vb × T) × 100 (1)
Non-vibration porosity (volume%) = 100−W / (Vw × T) × 100 (2)
Mortar flow rate (% by volume) = 100 × Vf / Vo (3)
(Wherein, W represents the mass of the porous concrete charged into the mold, Vb represents the volume of the porous concrete after vibration, and T represents the unit of blending the porous concrete calculated with the porosity being 0% by volume. It represents the volume mass, Vw represents the volume of the porous concrete when the settlement due to the loading of the weight is stopped, Vf represents the volume of the mortar that has flowed down by the vibration, and Vo represents the volume of the mortar in the porous concrete before the vibration. Represents.)
[Composition A]

The unit amount of Portland cement is 130 to 500 kg / m ³ , the unit amount of fine aggregate is 40 to 300 kg / m ³ , the unit amount of coarse aggregate is 1100 to 1900 kg / m ³ , and the unit amount of water is 40 to 150 kg / m The method for producing cast-in-place porous concrete according to claim 1, wherein the unit amount of m ³ and the high-performance AE water reducing agent is 0.7 to 15.0 kg / m ³ . Furthermore, the manufacturing method of the cast-in-place porous concrete of Claim 2 whose unit amount of a thickener is 0.5 kg / m < ³ > or less. Furthermore, the manufacturing method of the in-situ porous concrete of Claim 2 or 3 whose unit amount of an inorganic type admixture is 15 kg / m < ³ > or less.

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