JP2003238224A - Wet porous concrete - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain wet porous concrete which forms a wet environment profitable for animals and plants without adversely affecting environments of growing the animals and plants. <P>SOLUTION: The wet porous concrete is cement-based concrete obtained by using, as admixtures, aggregate having a maximum size of ≤25 mm and vegetable short fiber. The concrete is characterized in that the porosity is 10 to 20%, the coefficient of water permeability is ≥1.0 and <3.0 cm/sec, the water absorption amount per unit volume is ≥100 L/m<SP>3</SP>, and the dewatering amount per unit volume is ≥50 L/m<SP>3</SP>. The concrete has high ability to suck up water and high water retention performance to stable store the sucked water in the inside, and further the concrete has mechanical strengths, therefore, the concrete is preferably used as a structural material arranged in a waterfront for protecting the environment. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a highly water-absorbing / water-retaining concrete (wet porous concrete) having a water-retaining function similar to soil and a plant / animal growing function.

[0002]

2. Description of the Related Art Conventionally, cement concrete has been widely used as a basic material constituting various structures, but recently, concrete products and structures have been
Unlike natural materials such as soil and rocks, it is said that it has a bad influence on the surrounding environment and living things, and the use of concrete has started to be restricted in projects such as river maintenance.

[0003] Actually, in the revetment concrete used for rivers, harbors and coasts, concrete retaining walls for soil, and in concrete waterways for small rivers and agricultural water, plants propagate in the concrete portion. It does not happen to living things (small animals and microorganisms).

Water is indispensable for the growth environment of plants and animals. However, even in the case of concrete structures that may come into contact with water, since the original function of concrete often requires watertightness, unless otherwise specified, the growth environment of plants and animals cannot be formed inside concrete. Absent. What is special is, for example, a case where algae or moss plants propagate on the concrete surface in a humid place such as a shade that blocks direct sunlight from the sun. This is because even if the moisture in the air adheres to the concrete surface, it is provided with the condition that it can avoid the rapid drying and always keep the surface water.

Since a normal concrete structure does not have a water retaining function even when it is wet with water, if the moisture is evaporated by direct sunlight of the sun, the concrete will be in a dry state and the surface will be dried. For this reason, for example, plants such as concrete retaining wall blocks used for earth retaining do not settle and small animals do not inhabit. In other words, it may be considered the worst ecological environment for plants and animals.

On the other hand, it is a fact that cement concrete is excellent in workability, safety and economy.
It is difficult to find an alternative material to concrete for structural and mechanical problems.

[0007] Therefore, while the characteristics of such cement-based concrete are utilized, the appearance of concrete that has a water-retaining function similar to soil and can form an ecological environment for plants and living things (small animals and microorganisms) is awaited. is there.

On the other hand, in recent years, porous porous concrete capable of planting plants such as grass and ivy has begun to be used as revetment for river banks and greening concrete on slopes of constructed land. Such porous concrete has voids secured mainly by adjusting the grain size of the aggregate, and by filling the voids with a vegetation base, plants and micro aquatic animals can inhabit. In addition to these applications, porous concrete has also been attempted to be used as a noise-reducing road pavement material that is expected to absorb the sound of its voids, or as a drainage pavement material that utilizes high water permeability.

However, conventional porous concrete has a passage through which water can escape, and the cement matrix itself does not have water retention. For this reason, concrete itself has a low ability to retain water so that it can store water, and when expecting this, large voids that can be filled with soil etc. are required. However, with this, it is difficult to develop sufficient strength as concrete, and its applications are limited.

[0010]

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a concrete having a workability, safety, economic efficiency and mechanical strength similar to ordinary concrete, but also having water-absorbing and water-containing performance and an animal and plant growth function. Is to get.

[0011]

According to the present invention, in a concrete mixture comprising cement, aggregate, plant short fibers, water and an admixture, the porosity is adjusted to 15 to 20% by adjusting the aggregate particle size and the amount of water, and 20 kg / m ³ or more of plant short fibers are dispersedly contained to have a water permeability of 1.0 to 3.0 cm / se.
Wet porous concrete having a hardness of less than c is provided. More specifically, it is a cement concrete using an aggregate and a plant short fiber having a maximum size of 25 mm as an admixture, and a water permeability coefficient: 1.0 to less than 3.0 cm / sec, a unit water absorption amount: 100 L / m ³ or more (L represents liter, the same applies hereinafter), preferably 140 L / m ³ or more, more preferably 160 L / m ³ or more, unit dehydration amount: 50 L / m ³ or more, preferably 70 L / m ³
Above, more preferably, 80 L / m ³ or more of wet porous concrete is provided.

Here, the unit water absorption is measured by measuring the weight Wd (Kg) of a cylindrical specimen having a diameter of 10 cm and a height of 20 cm in an oven at 110 ° C. and a humidity of 0% in an absolutely dry state.
The weight Ww (Kg) at the time when water was continuously supplied to the entire test piece in the absolutely dry state for 24 hours was measured and defined as a value of (Ww-Wd) / V. In addition, the unit dehydration amount was determined by immersing the entire cylindrical specimen having a diameter of 10 cm and a height of 20 cm in water until the weight change no longer occurred, and measuring the constant weight Wc at 30 ° C.
The weight We after being kept in the dryer for 24 hours is measured and defined as the value of (Wc-We) / V. A large unit dehydration amount means that a large amount of water can be retained until 30 hours at 30 ° C, that is, the water retention performance is high.

The wet porous concrete of the present invention is an ordinary cement, an aggregate having a maximum size of 25 mm or less, a cement concrete using water and an admixture, and having a porosity of 15 to 20% by adjusting the aggregate particle size and the amount of water. 20kg / m ³ or more of plant short fibers, preferably 3
By blending more than 0 Kg / m ³ , unit water absorption becomes 1
00L / m ³ or higher, preferably 140L / m ³ or more, the unit amount of dehydration 50L / m ³ or more preferably those with 70L / m ³ or more. At least one kind of hemp, cotton, paddy, and straw can be used as a raw material for the plant short fiber, and a lightweight aggregate having a maximum size of 25 mm can also be used as the aggregate. When lightweight aggregate is used, wet porous concrete with an air-dry specific gravity of 1.7 or less can be obtained. As the admixture, it is preferable to use a high performance AE water reducing agent, an AE water reducing agent and a thickening agent.

[0014]

DETAILED DESCRIPTION OF THE INVENTION

The present inventors have found that since moisture retention is not sufficient in so-called porous concrete in which aggregate is hardened with cement with a gap, moisture is not retained in the part exposed to the air, and as a result, animals and plants are not always retained. I learned that it is not a suitable material for the growing environment. In addition, the strength of conventional porous concrete decreases as the porosity increases, and its use in revetments and waterfront structures may be restricted. The wet porous concrete according to the present invention secures the porosity of 15 to 20%, which is possessed by the conventional porous concrete, and retains the water permeability, while additionally adding the water absorption and the water retention (water content) which the porous concrete does not have. In addition, it is characterized in that it also develops the strength required as a structural material. As a new structure for this purpose, short fiber plant is incorporated.

FIG. 1 schematically shows the characteristics of the wet porous concrete of the present invention in comparison with the porous concrete. As shown in the figure, the original function of porous concrete is the permeability that water from above easily escapes (flows down), and does not have the water-holding and water-containing functions of concrete itself. For this reason, the inside of porous concrete is extremely dry, and in order to retain water for greening, etc., it is necessary to consider a combination with a water retaining material.

Although the wet porous concrete according to the present invention also has water permeability, it can absorb a large amount of water and can always contain water. If this is expressed numerically, both are manufactured by adjusting the aggregate particle size and water content so that they have a porosity of 15 to 20%, but the hydraulic conductivity of porous concrete is 3.0 to 5.0 cm / sec. In wet porous concrete, it is on the low frequency side of 1.0 to less than 3.0 cm / sec. And the unit water absorption and unit dehydration are, for example, 170 L / m ³ and 90 L for wet porous concrete.
/ M ³ indicates, high beyond comparison with porous concrete. This is brought about by the addition of plant short fibers to ordinary porous concrete compounding materials,
It can be considered that this causes the water absorbing and water containing functions to be exhibited in the concrete.

The plant short fibers used in the present invention are, for example, hemp,
It is made from plant fibers such as cotton, paddy, and straw.
When they are dispersed and mixed in concrete, they can form fine water passages, and the capillary passages absorb and retain water. Therefore, it is possible to maintain a wet state at all times by giving appropriate amount of water.

That is, according to the present invention, it is possible to obtain a wet porous concrete having a water absorbing action, a water retaining action, a water containing action, an evapotranspiration action, and a capillary action, and since such action is similar to natural soil, It helps to create a flora and fauna that fits the ecosystem. This is in sharp contrast to the fact that conventional concrete impairs the formation of the growth environment for plants and animals.

The matters specified in the present invention will be described below.

The wet porous concrete of the present invention can be constructed by using the same materials as those of the conventional porous concrete except the plant short fibers. That is, as in the case of ordinary porous concrete, a coarse aggregate having a maximum size of 25 mm, preferably a maximum size of 20 mm is used as an admixture, and fine aggregate is mixed if necessary (when fine aggregate is not used, There is also a gap) and cement the coarse aggregates with cement. The voids are preferably 10 to 20% in porosity. It is also possible to use lightweight aggregate as aggregate, which makes it possible to obtain lightweight wet porous concrete having an air-dry specific gravity of 1.7 or less.

In porous concrete having a porosity of 10 to 20%, the water permeability becomes about 3.0 to 5.0 cm / sec, but in the wet porous concrete of the present invention, by mixing plant short fibers, the water permeability is 10 to 20%. Coefficient 1.0 ~
Less than 3.0 cm / sec. The amount of plant short fiber is 2
It is preferable to set it in the range of 0 to 80 Kg / m ³ , and the wet performance of the wet porous concrete increases as the blending amount of the plant short fibers increases. However, it increased where the aggregate surface is covered with plants short fibers, since would degrade the bonding strength between the aggregate, cement, 80 Kg / m ³ or less, and it is preferably a 60 Kg / m ³ or less . When kneading, mix the cement paste with plant short fiber first,
A method of mixing the cement paste containing the plant short fibers with the coarse aggregate is preferable. In general, short plant fibers have the property of being hard to corrode when mixed with concrete. For example, hemp has been found to have not corroded even in Egyptian pyramids.

When using short vegetable fibers, it is preferable to knead them in a state of being well loosened. Due to the nature of plant short fibers,
The diameter and length of each fiber, as well as the surface state and shape (whether needle-shaped or plate-shaped) are random, but the point is that they are well dispersed in concrete depending on the nature of the plant short fibers. The size and shape should be such that it can be achieved. Taking hemp as an example, the length is 2 to 12 mm and the diameter is 0.2 to 0.7 m.
A short fiber of about m may be added little by little to the concrete being mixed and dispersed. At that time, it is preferable to carry out dry kneading before mixing water for 60 seconds or more. It is also preferable to add a dispersant for concrete, for example, a high-performance water reducing agent (Rheobuild (registered trademark) 8000ES, etc.) to the concrete to promote dispersion of the plant short fibers.

In a material composition that provides a porosity of 10 to 20%, and when plant short fibers are further compounded at 20 Kg / m ³ or more, the water-cement ratio is made higher than that of porous concrete (for example, in porous concrete. When water cement is about 25-35% and wet porous concrete is increased to about 35-45%), a kneaded product with a slump value of about 1.0 cm or less is obtained. Wet porous concrete having a coefficient of 1.0 to less than 3.0 cm / sec, a unit water absorption amount of 100 to 200 L / m ³ , and a unit dehydration amount of 50 to 100 L / m ³ can be obtained.

Typical wet porous concrete material composition examples are: water: 140 to 200 kg / m ³ cement: 350 to 500 kg / m ³ water cement ratio: 35 to 45% ordinary aggregate: 1000 to 1600 kg / m ³ vegetable short fibers: 20 to 80 Kg / m ^{3 As an} admixture, a high performance water reducing agent: 4 to 5 Kg / m ³ thickener: 0.3 to 1.0 Kg / m ³ can be exemplified.

In addition, as an example of the material composition when the lightweight aggregate is used, water: 180 to 240 Kg / m ³ cement: 400 to 600 Kg / m ³ water cement ratio: 40 to 45% lightweight aggregate: 300 to 800 L Fine aggregate: 200 to 600 Kg / m ³ Plant short fiber: 20 to 80 Kg / m ^{3 As an} admixture, a high-performance water reducing agent: 4 to 5 Kg / m ³ can be exemplified.

[0027]

【Example】

Example 1 Wet porous concrete was produced with the composition shown in Table 1 and the following design criteria. Design standard strength f'ck = 80 kgf / cm ² Maximum size of coarse aggregate = 20 mm Slump range = 1.0 cm or less Porosity = 15 to 20% Water cement ratio = 40% Permeability coefficient = 1.0 to 3.0 cm / Sec Air-dry specific gravity = 1.90

[0029]

[Table 1]

The aggregate used is from Kuzuu-cho, Tochigi Prefecture (G: 2005, manufactured by Komagata Lime Industry Co., Ltd.), the thickener is SFCA2000 manufactured by Shin-Etsu Chemical Co., Ltd., and the admixture is 8000ES manufactured by NMB Co., Ltd. Is. As the plant short fibers, hemp short fibers were used.

The fresh concrete obtained had a slump of 0.0 cm. The compressive strength and bending strength of the cured product were the following average values of the three test pieces. The appearance of the cured product was similar to "coarse grained". Compressive strength age 3 days = 19.6 kgf / cm ² Age 7 days = 44.3 kgf / cm ² Age 14 days = 83.8 kgf / cm ² Age 28 days = 123 kgf / cm ² Bending strength age 28 days = 25.1kgf / cm ²

The following results were obtained in the length test in water and air. Underwater 3 days 407.22 mm Air dry 3 days 407.21 mm Air dry 7 days 407.10 mm Air dry 14 days 406.15 mm Air dry 28 days 406.12 mm Air dry 91 days 406.07 mm

Using a specimen of 10 days old (a cylinder specimen having a diameter of 10 cm, a height of 20 cm and a volume of 1.57 liters), changes with time of the unit water absorption amount and the unit dehydration amount were measured under the following conditions.

Measurement of unit water absorption: A test piece of 10 days old was wetted once, and dried in a drier (humidity 0%) at 110 ° C. for 5 days.
It was dried for a day to an absolute dry state. The dry weight Wd was 2.750 Kg. Water is continuously supplied to this absolutely dry specimen, and the weight W at each elapsed time from the start of water supply
Wn (Kg) is measured and the unit water absorption (Wwn-Wd) / V
(L / m ³ ) was determined. The results are shown in Table 2 and FIG. The volume percentage of the unit water absorption is taken as the unit water absorption rate (%),
It is also shown in Table 2.

Measurement of unit dehydration amount: A specimen of 8 days old was immersed in water for 3 days, and it was confirmed that the weight did not change any more, and the constant weight Wc (Kg) was measured. Three
The weight Wen (Kg) of each elapsed time is measured in a dryer at 0 ° C to obtain (Wc-Wen) / V. The results are shown in Table 3 and FIG. In addition, the volume percentage is also shown in Table 3 as the unit dehydration rate.

[0036]

[Table 2]

[0037]

[Table 3]

From the results shown in Table 2 (FIG. 2), the concrete of this example has a high water absorption capacity of about 166 liters / m ³ when water is continuously supplied for 24 hours. Since it reached near the amount in a few hours, it is clear that the ability to actively absorb water is extremely high.

From the results shown in Table 3 (FIG. 3), the concrete of this example had a unit dehydration amount after 24 hours at 30 ° C. of 82 liters / m ³ and had a very high water retention function, and after that, It continues to dehydrate after 2, 3, 4, 5, 6, 7 days and the unit dehydration rate after 7 days is 108 liters /
Since it has reached m ³ , it can be seen that it reluctantly holds water and has extremely high water-containing and water-retaining functions.

Example 2 A lightweight wet porous concrete was produced with the composition shown in Table 4 and the following design criteria. Design standard strength f'ck = 80 kgf / cm ² Maximum size of coarse aggregate = 25 mm Slump range = 1.0 cm or less Porosity = 10 to 15% Water cement ratio = 40% Water permeability = 0.1 to 0.5 cm / Sec Air dry specific gravity = 1.55

[0041]

[Table 4]

The aggregate used is a lightweight aggregate manufactured by Arano Pearlite Co., Ltd. and the fine aggregate manufactured by Ari Kogyo Co., Ltd., and the admixture is 8000ES manufactured by NM Co., Ltd. As the plant short fibers, hemp short fibers were used.

The fresh concrete obtained had a slump of 0.0 cm. The compressive strength and bending strength of the cured product were the following average values of the three test pieces. The appearance of the cured product was similar to that of "fine grained rice". Compressive strength age 3 days = 20.8 kgf / cm ² Age 7 days = 52.8 kgf / cm ² Age 14 days = 102 kgf / cm ² Age 28 days = 121 kgf / cm ² Bending strength age 28 days = 25 .4 kgf / cm ²

The following results were obtained in the length test in water and air. Underwater 3 days 406.34 mm Air dry 3 days 406.11 mm Air dry 7 days 405.84 mm Air dry 14 days 405.81 mm Air dry 28 days 405.78 mm Air dry 91 days 405.70 mm

Using a specimen of 10 days of age (a cylindrical specimen having a diameter of 10 cm, a height of 20 cm and a volume of 1.57 liters), the changes with time in the unit water absorption amount and the unit dehydration amount were measured under the following conditions.

Measurement of unit water absorption: A test piece of 21 days old was wetted once and then dried at 110 ° C. in a dryer (0% humidity) for 5 times.
It was dried for a day to an absolute dry state. The absolutely dry weight Wd was 2.050 Kg. Water is continuously supplied to this absolutely dry specimen, and the weight W at each elapsed time from the start of water supply
Wn (Kg) is measured and the unit water absorption (Wwn-Wd) / V
(L / m ³ ) was determined. The results are shown in Table 5 and FIG. The volume percentage of the unit water absorption is taken as the unit water absorption rate (%),
It is also shown in Table 5.

Measurement of unit dehydration amount: A specimen of 29 days old was immersed in water for 5 days, and it was confirmed that the weight did not change any more, and the constant weight Wc (Kg) was measured. Weight Wen (Kg) per elapsed time in a dryer at 30 ° C
Is measured to obtain (Wc-Wen) / V. The results are shown in Table 6 and FIG. In addition, the volume% is also shown in Table 6 as the unit dehydration rate.

[0048]

[Table 5]

[0049]

[Table 6]

From the results shown in Table 5 (FIG. 4), the lightweight concrete of this example has a unit water absorption of about 376 liters / m ^{3 when} it is continuously supplied with water for 24 hours, which is an extremely large amount of water absorption.
This unit water absorption was 369 liters / m ^{3 in} about 3 hours.
From this, it is clear that the water absorption capacity is also extremely high.

From the results shown in Table 6 (FIG. 5), the lightweight concrete of this example has a unit dewatering amount of 153 liters / m ³ after 24 hours at 30 ° C., and has a very high water retention function, and then 2 , 3, 4, 5, 6, 7 and 7 days later, the water continues to dehydrate, and the unit dehydration rate after 7 days reaches almost 270 liters / m ³ . That is, it can be seen that the water-containing / water-retaining function is extremely high because water can be gradually released even at 30 ° C for a long time.

Comparative Example Porous concrete was produced with the composition shown in Table 7 and the following design criteria. Design standard strength f'ck = 80 kgf / cm ² Maximum size of coarse aggregate = 20 mm Slump range = 1.0 cm or less Porosity = 20-25% Water-cement ratio = 28% Water permeability = 3.0-5.0 cm / Sec Air-dry specific gravity = 1.78

[0053]

[Table 7]

The aggregate used is from Kuzuu-cho, Tochigi Prefecture (Komagata Lime Industry Co., Ltd. G: 2005), the thickener is SFCA2000 manufactured by Shin-Etsu Chemical Co., Ltd., and the admixture is 8000ES manufactured by NMB Co., Ltd. Is.

The fresh concrete obtained had a slump of 0.0 cm. The compressive strength and bending strength of the cured product were the following average values of the three test pieces. The appearance of the cured product was similar to "Okoshi". Compressive strength material age 3 days = 48.4kgf / cm ² material age 7 days = 71.2kgf / cm ² material age 14 days = 100 kgf / cm ² material age 28 = 111kgf / cm ² flexural strength material age 28 = 15 0.0 kgf / cm ²

The following results were obtained in the length test in water and air. Underwater 3 days 406.82 mm Air dry 3 days 406.78 mm Air dry 7 days 406.75 mm Air dry 14 days 406.75 mm Air dry 28 days 406.64 mm Air dry 91 days 406.48 mm

Using a specimen of 10 days of age (a cylindrical specimen having a diameter of 10 cm, a height of 20 cm and a volume of 1.57 liters), the changes with time in the unit water absorption amount and the unit dehydration amount were measured under the following conditions.

Measurement of water absorption per unit: A test piece of 13 days old was once moistened and dried in a drier (0% humidity) at 110 ° C. for 5 times.
It was dried for a day to an absolute dry state. The weight Wd in an absolutely dry state was 2.720 Kg. Water is continuously supplied to this absolutely dry specimen, and the weight W at each elapsed time from the start of water supply
Wn (Kg) is measured and the unit water absorption (Wwn-Wd) / V
(L / m ³ ) was determined. The results are shown in Table 8 and FIG. The volume percentage of the unit water absorption is taken as the unit water absorption rate (%),
It is also shown in Table 8.

Measurement of unit dehydration amount: A specimen of 11 days of age was immersed in water for 3 days, and it was confirmed that no change in weight was observed, and the constant weight Wc (Kg) was measured. Weight Wen (Kg) per elapsed time in a dryer at 30 ° C
Is measured to obtain (Wc-Wen) / V. The results are shown in Table 9 and FIG. 7. Further, the volume% is also shown in Table 9 as the unit dehydration rate.

[0060]

[Table 8]

[0061]

[Table 9]

From the results of Table 8 (FIG. 6), the porous concrete of this example has a unit water absorption of about 57 liters / m ³ when water is continuously supplied for 24 hours.
The water absorption capacity is extremely lower than that of

From the results shown in Table 9 (FIG. 7), the concrete of this example has a unit dehydration amount of 45 liters / m ³ after 24 hours at 30 ° C., and the amount of water absorbed in two days is completely dehydrated. Will be done. That is, the water retention capacity is extremely lower than that of the first and second embodiments.

[0064]

As described above, according to the present invention,
Wet porous concrete that has a high ability to absorb water and that retains the absorbed water stably can be obtained, and the compressive strength is sufficiently high as a porous concrete, and the bending strength is also high. high. Therefore, it is possible to provide a material suitable for the conservation of the flora and fauna growth environment, and a concrete material suitable as a construction material suitable for the environment, particularly a construction for a waterside installation.

[Brief description of drawings]

FIG. 1 is a functional explanatory view showing the wet porous concrete of the present invention in comparison with the porous concrete.

FIG. 2 is a diagram showing a change with time of a unit water absorption amount of the wet porous concrete according to the present invention.

FIG. 3 is a diagram showing changes over time in the unit dehydration amount of wet porous concrete according to the present invention.

FIG. 4 is a diagram showing a change with time of a unit water absorption amount of wet porous concrete according to another example of the present invention.

FIG. 5 is a diagram showing changes over time in the unit dehydration amount of wet porous concrete according to another example of the present invention.

FIG. 6 is a view showing a change with time of a unit water absorption amount of porous concrete of a comparative example.

FIG. 7 is a view showing a change with time of a unit dehydration amount of porous concrete of a comparative example.

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) C04B 20:00 C04B 16:02 Z 16:02) 111: 40 111: 40 (72) Inventor Kikuo Ozeki Tokyo Motoko Akasaka 1-2-7 Kashima Construction Co., Ltd., Minato-ku, Tokyo (72) Inventor, Hanako Nakamura Tokyo Moto-Akasaka 1-2-7 Kashima Construction Co., Ltd., Minato-ku (72) Inventor, Hiroshi Karaki Tokyo 4, 2-3 Shiba, Minato-ku, Geostar Co., Ltd. (72) Inventor Takao Uchikawa 4-3, Shiba 4-chome, Minato-ku, Tokyo (72) Inventor, Akira Kase 4-chome, Shiba, Minato-ku, Tokyo 2-3 Geostar Co., Ltd. (72) Inventor Atsushi Yokoo 2-3-4 Shiba, Minato-ku, Tokyo Geostar Co., Ltd. F-term (reference) 2D018 DA00 4G012 PA02 PA22 PC11 4G019 CA01 CB06

Claims (6)

[Claims] 1. In a concrete mixture comprising cement, aggregate, plant short fibers, water and an admixture, the porosity is adjusted to 15 to 20% and 20 kg by adjusting the particle size of aggregate and the amount of water.
/ M ³ or more plant short fibers are dispersedly contained to make the hydraulic conductivity 1.
Wet porous concrete with 0 to less than 3.0 cm / sec. 2. A cement-based concrete using aggregates having a maximum size of 25 mm or less and plant short fibers as admixtures, and water permeability coefficient: 1.0 to less than 3.0 cm / sec, the measuring method of (1) below. Wet porous concrete with a unit water absorption of 100 L / m ³ or more and a unit dewatering amount of 50 L / m ³ or more according to the measurement method of (2) below. (1) Unit water absorption measurement method: diameter 10 cm, height 20 cm
The cylindrical specimen of No. 1 was dried in a dryer at 110 ° C and a humidity of 0%, and its weight Wd (Kg) was measured. The weight Ww at the time when water was continuously supplied to the entire dried specimen for 24 hours
(Kg) is measured to obtain (Ww-Wd) / V. (2) Measuring method of unit dehydration amount: diameter 10 cm and height 20 cm
The entire cylindrical specimen of No. 3 was immersed in water until the weight did not change, and the constant weight Wc (Kg) was measured.
Weight We when kept in a dryer at 0 ° C for 24 hours
(Kg) is measured to obtain (Wc-We) / V. 3. A plant short fiber content of 20 kg / m ³ or more, a unit water absorption of 140 L / m ³ or more, and a unit dehydration amount:
The wet porous concrete according to claim 2, which has a content of 70 L / m ³ or more. 4. A plant short fiber content of 30 kg / m ³ or more, a unit water absorption of 160 L / m ³ or more, and a unit dehydration amount:
The wet porous concrete according to claim 2, which has a rate of 80 L / m ³ or more. 5. The wet porous concrete according to any one of claims 1 to 4, wherein the plant short fiber is made of at least one of hemp, cotton, paddy and straw. 6. The wet porous concrete according to claim 1, wherein a lightweight aggregate having a maximum size of 25 mm is used as an admixture and the air-dry specific gravity is 1.7 or less.