JP2001071313A - Manufacture of porous concrete - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing a porous concrete which can be manufactured without kneading and is excellent in workability. SOLUTION: In this method for manufacturing a porous concrete, the porous concrete is made by casting cement paste or mortar over coarse aggregates 2 of a roadbed ballast and curing the cement paste or the mortar into a monolithic form. In this case, cement slurry with 150-250 mm, preferably 195-210 mm of flow rate is cast over the roadbed ballast 2, 80-100 wt.% of which passes through a 50 mm sieve opening, 95 wt.% or more remaining on a 20 mm-sieve opening. Further, the cement slurry is cured to integrate the roadbed ballast 2 and the cured product 3 of the cement slurry into one piece.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for producing porous concrete, and more particularly to a method for producing porous concrete excellent in workability.

[0002]

2. Description of the Related Art Conventionally, porous concrete having drainage properties has been used for concrete products requiring voids, for example,
It is widely used as a concrete product for forming seawall blocks, water purification blocks, vegetation (greening) blocks, fishing reef blocks, wave-dissipating blocks, etc., and concrete suitable for drainage, water permeability, pavement, sound absorption, non-slip, and the like. In order to obtain porous concrete, for example, coarse aggregate and cement paste or mortar are kneaded with a mixer or the like, and a cement slurry is adhered to the surface of the coarse aggregate, and the cement slurry is filled in a formwork, or on a roadbed. To harden the cement paste or mortar.

[0003]

However, in such a method for producing porous concrete, in order to make the cement paste or mortar adhere to the surface of the coarse aggregate, the coarse aggregate and the cement paste or mortar are all put into a mixer. In addition, it was necessary to knead, and a kneading device had to be prepared for kneading. In addition, the workability of porous concrete is poor, and the work of transporting, casting, compacting, finishing, and the like is extremely difficult, and dedicated equipment has been required. The present invention has been made in view of the above circumstances, solves the above problems, and provides a method of manufacturing porous concrete excellent in workability, which can be manufactured without kneading the coarse aggregate and cement paste or mortar at once. The task is to provide.

[0004]

Means for Solving the Problems In order to solve the above problems, a method for producing porous concrete according to the present invention comprises: flowing cement paste or mortar on coarse aggregate;
It is characterized in that the cement paste or the mortar is integrated by hardening. In addition, the above problem is that a cement paste or mortar having a flow value of 150 to 250 mm is placed on a ballast ballast that 80 to 100% by weight passes through a 50 mm sieve and 95% or more does not pass through a 20 mm sieve. The problem can be solved by a method for producing porous concrete, characterized in that adjacent coarse aggregates are consolidated and integrated by flowing and hardening a cement paste or a mortar, and that a gap between adjacent coarse aggregate particles is retained.

[0005] The above-mentioned problem is also solved on a coarse aggregate having a particle size of not less than 90% by weight that passes through a 40 mm sieve and not more than 95% by weight through a 30 mm sieve. Manufacturing of porous concrete characterized by flowing cement paste or mortar and hardening the cement paste or mortar to consolidate and integrate adjacent coarse aggregates, and to maintain voids between adjacent coarse aggregate particles. Can be solved by the method.

[0006] Another problem is that a flow rate of 195 to 295 mm is set on coarse aggregate having a particle size of 90% by weight or more that passes through a 30 mm sieve and 95% by weight or more that does not pass through a 20 mm sieve. Manufacturing of porous concrete characterized by flowing cement paste or mortar and hardening the cement paste or mortar to consolidate and integrate adjacent coarse aggregates, and to maintain voids between adjacent coarse aggregate particles. Can be solved by the method.

[0007] Further, the above-mentioned problem is that a flow rate of 235 mm or more is set on a coarse aggregate having a particle size of 90% by weight or more that passes through a 20 mm sieve and 95% by weight or more that does not pass through a 10 mm sieve. Flow cement paste or mortar, solidify and integrate adjacent coarse aggregates by hardening cement paste or mortar,
In addition, the problem can be solved by a method for producing porous concrete, characterized in that voids between adjacent coarse aggregate particles are maintained.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail.
The method for producing porous concrete of the present invention is a method in which a cement paste or mortar (hereinafter, referred to as a cement slurry) is flowed over coarse aggregate and the cement slurry is hardened to be integrated. This is a manufacturing method combining the particle size and the flow value of the cement slurry.

FIG. 1 is a perspective view showing an example of a porous concrete structure obtained by the method for producing porous concrete of the present invention. In FIG.
Denotes a porous concrete structure, reference numeral 2 denotes a coarse aggregate, and reference numeral 3 denotes a hardened cement slurry. The porous concrete structure 1 is manufactured, for example, as follows. First, a coarse aggregate 2 is filled into a mold or the like having an open upper surface. Then, this coarse aggregate 2
While the cement slurry is poured from above, vibration is given using a vibrator or the like. Then, this is cured, and the cement slurry is cured to obtain a cured product 3,
It is manufactured by a method of integrating the cured product 3 and the coarse aggregate 2. Thereby, the coarse aggregates 2 adjacent to each other are solidified and integrated with each other by the hardened material 3, and the porous concrete having sufficient voids between the particles of the adjacent coarse aggregates 2 is obtained. Such porous concrete is excellent in drainage (water permeability).

In this manufacturing method, as the coarse aggregate 2,
When using a ballast ballast having a particle size such that 80% by weight or more passes through a sieve having an aperture of 50 mm and 95% by weight or more does not pass through a sieve having an aperture of 20 mm, a flow value of 150 to 250 mm is preferable. Is 195-2
A 10 mm cement slurry is used. Here, the “flow value” refers to a flow value measured according to the physical test method of JIS R5201 cement.

When a cement slurry having a flow value of less than 150 mm is used, the coarse aggregate
Since it becomes difficult to penetrate between the parts, it becomes impossible to reach the coarse aggregate 2b constituting the lower part 1b of the porous concrete structure 1, so that even if the cement slurry is hardened, the lower part 1b of the porous concrete structure 1 is not integrated. It is not preferable because of fear. On the other hand, if the flow value is 25
When a cement slurry exceeding 0 mm is used, the amount of cement slurry remaining between the coarse aggregates 2a constituting the upper part 1a of the porous concrete structure 1 is reduced, and even if the cement slurry is hardened, It is not preferable because the adhesion between the coarse aggregates 2a constituting the upper part 1a of the porous concrete structure 1 cannot be sufficiently obtained, and the upper part 1b of the porous concrete structure 1 may not be integrated. Further, the amount of the poured cement slurry deposited on the bottom surface of the mold increases, and it may not be possible to obtain sufficient drainage.

The cement slurry used here is preferably a general one composed of cement, water and fine aggregate added as necessary, and the amount of the cement slurry is determined according to the purpose of the porous concrete. Is determined according to. Further, if necessary, admixtures such as blast furnace slag fine powder, fly ash, silica fume, and limestone fine powder, water reducing agents, thickeners, and the like may be added. As the cement used here, ordinary Portland cement,
Examples include early-strength Portland cement, low-heat Portland cement, blast furnace cement, fly ash cement, ultra-rapid hardening cement, and the like, which are suitable for use in porous concrete.

Furthermore, the amount of cement slurry used here is preferably 0.1 to ³ m ³ of coarse aggregate 2.
割 合 0.4 m ³ . If the amount of the cement slurry is less than 0.1 m ³ , it is not preferable because the coarse aggregate 2 may not be integrated. On the other hand, when the amount is more than 0.4 m ³ , voids are reduced and drainage becomes insufficient, which is not preferable.

Examples of the curing method include, but are not particularly limited to, general methods such as natural curing, wet curing, steam curing, heating curing, and autoclave curing.

[0015] The method for producing such a porous concrete uses a ballast ballast in which 80% by weight or more passes through a sieve having a particle size of 50 mm and 95% by weight or more stays on a 20 mm sieve. Flow value is 150
Since the cement slurry having a thickness of about 250 mm, preferably 195 to 210 mm, is flowed and hardened, the cement slurry is sufficiently infiltrated between adjacent coarse aggregates 2 and porous. The cement slurry can reach the coarse aggregate 2b constituting the lower part 1b of the concrete structure 1 and the cement slurry sufficiently remains between the coarse aggregates 2a constituting the upper part 1a of the porous concrete structure 1, so that the porous concrete The adhesive strength between the coarse aggregates 2a constituting the structure 1 is sufficiently obtained. Therefore, the porous concrete can be easily manufactured without kneading, and the labor for manufacturing can be reduced as compared with the case where the porous concrete is manufactured by the conventional manufacturing method of the porous concrete.

In the method for producing porous concrete according to the present invention, the combination of the particle size of the coarse aggregate and the flow value of the cement slurry is not limited to the above-mentioned combination alone. The following combinations (1) to (3) may be used. (1) 90% by weight of 40 mm sieve as coarse aggregate 2
When coarse aggregate having a particle size of 95% by weight or more (i.e., not passing) is used on a 30 mm sieve, the cement having a flow value of 150 to 250 mm, preferably 195 to 210 mm is used. A slurry is used. The coarse aggregate having such a particle size can be easily obtained by classifying a common crushed stone for roads 4020 by a sieve having an opening of 30 mm. Further, in this case, since the coarse aggregate 2 has a particle size of approximately 30 to 40 mm, it is possible to manufacture porous concrete having a large gap of about 15 mm in diameter.

(2) When coarse aggregate having a particle size of 90% by weight or more that passes through a 30 mm sieve as a coarse aggregate 2 and 95% by weight or more stays on a 20 mm sieve is used, Values between 195 and 295 mm, preferably 240
セ メ ン ト 255 mm cement slurry is used. Coarse aggregate having such a particle size can be easily obtained by classifying a common road crushed stone 4020 with a 30 mm sieve. In this case, since the coarse aggregate 2 has a particle size of approximately 20 to 30 mm, the diameter of the coarse aggregate 2 is 1 mm.
Porous concrete having a void of about 0 mm and having a large resistance to an overload can be manufactured.

(3) 90% or more of the coarse aggregate 2 passes through a 20 mm sieve, and 95% of the coarse aggregate 2 is placed on the 10 mm sieve.
In the case of using coarse aggregate with a particle size of more than
A cement slurry having a flow value of 235 mm or more, preferably 280 mm or more is used. Coarse aggregates having such a particle size are common as road crushed stones 2013 and can be easily obtained. In this case, the coarse aggregate 2
Is about 20 to 10 mm, the diameter of the voids is about 5 mm, and it is possible to manufacture porous concrete having a large resistance to an overload.

[0019] Even when the combination of the particle size of the coarse aggregate 2 and the flow value of the cement slurry is the combination shown in the above (1) to (3), the cement slurry may be placed between adjacent coarse aggregates 2. Enough to reach the coarse aggregate 2b constituting the lower part 1b of the porous concrete structure 1 shown in FIG. 1, and between the coarse aggregates 2a constituting the upper part 1a of the porous concrete structure 1. Since the cement slurry remains sufficiently, the adhesive strength between the coarse aggregates 2a constituting the porous concrete structure 1 can be sufficiently obtained. Therefore, the porous concrete can be easily manufactured without kneading.

In the method for producing porous concrete of the present invention, as shown in the above-described example, it is desirable to apply vibration using a vibrator or the like to cause the cement slurry to flow down, but it is not necessary to apply vibration.

[0021]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to embodiments. In the following test examples,% means% by weight. (Test Example 1) 150 mm in diameter and 3 in height with open top
Inside a 00 mm formwork, the total opening is 50 mm
80% to 100% pass through the sieve, and 95% or more of the total amount remains on the sieve having the aperture of 20 mm.
250m high, using ballast for ballast for railway tracks as coarse aggregate
m, and a cement slurry having a flow value of 240 mm was poured thereinto, vibrated by using a vibrator, and then cured to harden the cement slurry to obtain a test specimen. (Test Example 2 to Test Example 4) The flow values of the cement slurry were 225 mm (Test Example 2), 209 mm (Test Example 3), 1
A test body was obtained in the same manner as in Test Example 1, except that the test piece was changed to 95 mm (Test Example 4).

(Test Example 5 to Test Example 8) A road crushed stone having a particle size of 90% or more that passes through a sieve having an aperture of 40 mm and remains 95% or more on a sieve having an aperture of 30 mm,
Specimens were obtained in the same manner as in Test Example 1, except that the flow value of the cement slurry was changed to 240 mm (Test Example 5), 225 mm (Test Example 6), 209 mm (Test Example 7), and 195 mm (Test Example 8).

(Test Examples 9 to 13) Road crushed stone having a particle size of 90% or more passing through a 30 mm sieve and 95% or more remaining on a 20 mm sieve, and having a cement slurry flow value of 261 mm (Test Example 9), 247
mm (Test Example 10), 240 mm (Test Example 11), 22
Specimens were obtained in the same manner as in Test Example 1, except that 5 mm (Test Example 12) and 195 mm (Test Example 13) were used.

(Test Examples 14 to 18) A road crushed stone having a particle size of 90% or more passing through a 20 mm sieve and 95% or more remaining on a 10 mm sieve, and having a cement slurry flow value of 320 mm (Test Example 14), 2
93 mm (Test Example 15), 284 mm (Test Example 16),
261 mm (Test Example 17), 240 mm (Test Example 18)
And a test body was obtained in the same manner as in Test Example 1.

(Test Example 19) A sieve of 10 mm
% Or more was passed, and 95% or more of the crushed stone was used as a road crushed stone, and a cement slurry having a flow value of 320 mm was obtained.

The following items were measured and evaluated for each of the test pieces thus obtained. [Arrival Depth of Cement Slurry] The depth from the upper surface of the coarse aggregate reached by the cement slurry was measured. [Deposition Depth of Cement Slurry] The depth from the bottom surface of the mold on which the cement slurry was deposited was measured.

[Evaluation] ：: The cement slurry reached the bottom of the mold, and no deposition of the cement slurry was observed. Δ: Cement slurry reaches the bottom surface of the mold, but the cement slurry is deposited, or the cement slurry reaches a depth of 150 mm or more and less than 250 mm. ×: Cement slurry reaching depth of less than 150 mm. Table 1 shows the results.

[0028]

[Table 1]

From Table 1, it can be seen that in Test Examples 1 to 18, the particle size of the aggregate and the flow value of the cement slurry are within the preferred ranges. In addition, in Test Example 19, it is found that the particle size of the aggregate is too small, which is not preferable.

[0030]

As described in detail above, the method for producing porous concrete according to the present invention is a method in which a cement slurry is flowed over coarse aggregate and the cement slurry is hardened to be integrated. The particle size of the coarse aggregate and the flow value of the cement slurry are defined as (A) to (D) below.
Because it is any method selected from, the cement slurry sufficiently penetrates between adjacent coarse aggregates,
Since the coarse aggregate forming the lower part of the porous concrete structure manufactured by this manufacturing method can be reached, and the cement slurry sufficiently remains between the coarse aggregates forming the upper part of the porous concrete structure. , Sufficient adhesive strength between the coarse aggregates can be obtained. Therefore, the porous concrete can be easily manufactured without kneading, and the construction period can be shortened as compared with the case where the porous concrete is manufactured by the conventional manufacturing method of the porous concrete.

(A) Of the total amount, 80 to 100% by weight passes through a 50 mm sieve, and a ballast ballast in which 95% or more weight remains on a 20 mm sieve, and a flow value of 150 to 250 mm, preferably 195-210mm
Use of cement slurry. (B) In the total amount, 90% or more of the crushed stone for roads passes through a 40 mm sieve and 95% by weight or more remains on a 30 mm sieve, and the flow value is 150 to 250.
mm, preferably 195 to 210 mm of cement slurry. (C) In the total amount, 90% or more of the weight of the crushed stone for roads passes through a 30 mm sieve, and 95% or more of the crushed stone remains on a 20 mm sieve.
A cement slurry of 95 mm, preferably 240-255 mm, is used. (D) In the total amount, 90% by weight or more of a crushed stone for roads having a particle size of 90% by weight or more passing through a 20 mm sieve and 95% by weight or more remaining on a 10 mm sieve, and having a flow value of 235 mm
Above, preferably a cement slurry of 280 mm or more is used.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an example of a porous concrete structure obtained by a method for producing porous concrete of the present invention.

[Explanation of symbols]

 Reference Signs List 1 Porous concrete structure 2 Coarse aggregate (ballast ballast) 3 Hardened cement slurry

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Mio Uchida 7-1-55 Minamienkajima Taisho-ku, Osaka-shi, Osaka Sumitomo Osaka Cement Co., Ltd. C-Concrete Research Laboratory F-term (reference) 4G052 BA01 BB03

Claims (5)

[Claims] 1. A method for producing porous concrete, comprising: flowing cement paste or mortar over coarse aggregate; and curing cement paste or mortar to integrate the cement paste or mortar. 2. A ballast ballast having a flow value of 150 to 25%, which passes 80 to 100% by weight through a 50 mm sieve and 95% or more does not pass through a 20 mm sieve.
Porous concrete characterized by flowing 0 mm cement paste or mortar, hardening the cement paste or mortar, solidifying and integrating adjacent coarse aggregates, and retaining voids between adjacent coarse aggregate particles. Manufacturing method. 3. On a coarse aggregate having a particle size of 90% by weight or more passing through a 40 mm sieve and not exceeding 95% by weight through a 30 mm sieve, a flow value of 150 to 250 m
m. A porous concrete characterized by flowing cement paste or mortar, hardening the cement paste or mortar, solidifying and integrating adjacent coarse aggregates, and retaining voids between adjacent coarse aggregate particles. Manufacturing method. 4. On a coarse aggregate having a particle size of not less than 90% by weight passing through a 30 mm sieve and not exceeding 95% by weight through a 20 mm sieve, a flow value of 195 to 295 m
m. A porous concrete characterized by flowing cement paste or mortar, hardening the cement paste or mortar, solidifying and integrating adjacent coarse aggregates, and retaining voids between adjacent coarse aggregate particles. Manufacturing method. 5. A cement paste or mortar having a flow value of 235 mm or more is placed on a coarse aggregate having a particle size of 90% by weight or more that passes through a 20 mm sieve and 95% by weight or more that does not pass through a 10 mm sieve. A method for producing porous concrete, characterized in that adjacent coarse aggregates are consolidated and integrated by flowing and hardening a cement paste or mortar, and that gaps between adjacent coarse aggregate particles are retained.