JP6867643B2 - Porous concrete using zeolite - Google Patents

Description

The present invention relates to porous concrete using zeolite as an aggregate, and particularly to porous concrete using zeolite, which is suitable for use for the purpose of water purification.

Conventionally, a water purification system has been installed in biotopes, which are habitats for scenic ponds and living things such as buildings and parks, in order to circulate and purify water to maintain clear water quality. However, since such a water purification system is composed of a circulation device, a high-speed filtration device, an ultraviolet irradiation device, a metal ion implantation device, etc., electricity is required for operation and maintenance is required.

On the other hand, as a water purification method that does not require electric power for operation, a method of putting an adsorbent or a purification agent into a polluted water area is also used. However, in a water area such as a river where there is a flow, there is a problem that it disappears due to the flow of the water area before the effects of the adsorbent and the purifying agent introduced are exhibited.

Therefore, in order to prevent the outflow of materials with a purifying function such as adsorbents and purifying agents (hereinafter referred to as "purifying functional materials"), a method of forming these purifying functional materials into large blocks and installing them in water areas. There is also a method of attaching a purification block to the revetment. However, there is a drawback that the contact area with polluted water becomes small, the efficiency of water purification is poor, the landscape is not preferable, and a load is applied to the natural world.

Regarding the blocking of the above-mentioned purifying functional material, prior documents have proposed to increase the porosity, form continuous voids, or use a solidified body having an adsorption function. .. In particular, for blocks in which continuous voids are formed, techniques for producing coarse aggregates, admixtures, and kneading of water and admixtures, and techniques for using zeolite powder as an adsorbent have been proposed.

For example, in Patent Document 1 (Japanese Unexamined Patent Publication No. 9-2882), water purification of water areas (bank protection of rivers, etc.), green concrete (slopes, etc.), permeable concrete (permeable pavement, etc.), carbon dioxide gas absorbers, etc. Regarding the concrete solidified body having continuous voids on the surface and the inside and the method for producing the concrete solidified body to be used, in order to obtain a concrete solidified body having a large porosity, a material having voids of uniform distribution and a simple method of such a concrete solidified body. Manufacturing method has been proposed. Specifically, a hydraulic powder substance such as cement, a water reducing agent, a thickener (nonionic cellulose ether, microbial polysaccharide, acrylic type), water, etc. are mixed in a mold containing coarse aggregate in advance. A method for producing a concrete solidified body having a large void ratio and a uniform concrete solidified body by pouring the cement paste and applying a vibrator or the like has been proposed.

Further, Patent Document 2 (Patent No. 4391064) proposes a concrete-like filler capable of adsorbing harmful substances around the structure by simply providing the filler around the structure. That is, in Patent Document 2, it is a method for producing a filler formed by mixing cement, water, and an aggregate, and a porous material zeolite is adopted as the aggregate, and this zeolite is used. After adding water to the water, the zeolite is treated with water, and a zeolite having a predetermined range of particle size is selected from the mixture of the treated zeolite and water and separated together with water. A method for producing a filler for producing a filler having a function of adsorbing harmful substances or water by the adsorption action of zeolite by further mixing cement with the mixture has been proposed.

Then, in Patent Document 3 (Japanese Patent No. 3379924), a porous cement cured product containing a zeolite analog is formed from a cement slurry containing a powdery or granular mineral material containing silica and alumina as main components. Therefore, an adsorbent that is porous with little change over time and has a remarkably excellent adsorption function has been proposed. This adsorbent contains 70 to 150 parts by mass of water, silica and alumina with respect to 100 parts by mass of cement. A cement slurry composed of 5 to 50 parts by mass of a powdery or granular mineral material containing a component as a main component is formed, and this is sequentially subjected to normal pressure high temperature curing and high pressure high temperature curing to be cured to form a porous structure.

Japanese Unexamined Patent Publication No. 9-2882 Japanese Patent No. 4391064 Japanese Patent No. 3379924

As described above, various proposals have been made for blocking the purifying functional material by increasing the porosity, forming continuous voids, or using a solidified body having an adsorption function. However, the technique proposed in Patent Document 1 increases the porosity by pouring cement paste into a mold containing coarse aggregate and applying a vibrator or the like, and requires mechanical work. In addition, it cannot be denied that the porosity may change depending on how the vibrator is applied, making it difficult to stabilize the quality.

Therefore, the first object of the present invention is to eliminate the process using such a machine and to provide a porous concrete having continuous voids, which can be provided with more stable quality, and a method for producing the same. ..

Further, in Patent Document 2, it is proposed to use zeolite having a particle size in a predetermined range as an aggregate and to adsorb harmful substances or water by the adsorption action of zeolite. However, the porosity has not been studied, and it cannot be said that the adsorption effect of the zeolite is maximized.

Therefore, a second object of the present invention is to provide porous concrete using zeolite, which maximizes the adsorption effect of zeolite used as an aggregate and has sufficient strength, and a method for producing the same.

In order to solve at least one of the above problems, the present invention provides porous concrete in which zeolite is used as an aggregate and the exposed area of zeolite as an aggregate is expanded, and the porous concrete is further provided. As a method for producing a porous block, the present invention provides a method in which a mold is filled with zeolite aggregate in advance and then a separately kneaded cement paste is poured over the upper surface of the zeolite aggregate to produce a porous block.

That is, the porous concrete according to the present invention is a porous concrete using zeolite as an aggregate, and the zeolite used as the aggregate is in a crushed state and is bonded by cement to be formed into a block shape as a whole. The crushed zeolite, which is hardened into blocks by concrete, is formed by exposing one surface of the zeolite.

In such porous concrete of the present invention, the exposed area of zeolite as an aggregate can be increased. Therefore, the porous structure of zeolite can adsorb pollutants in water bodies and pollutants in the atmosphere. That is, when the porous concrete of the present invention is installed in a water area, it can adsorb nitrogen and phosphorus flowing in from industrial wastewater, domestic wastewater, agricultural land, etc., and further, microorganisms acting as purifying bacteria are contained in the zeolite. Since it lives, it can also purify organic substances in rivers. As a result, we will provide a porous concrete block using zeolite as an aggregate that can purify water areas such as rivers, lakes and ponds, and atmospheric odors such as barns and factories without using large-scale equipment. be able to.

Since the porous concrete according to the present invention is formed in a block shape as a whole, it has a weight and strength that does not cause it to be washed away by a water stream or collapse even when it is installed in a basin. Since it can be manufactured, porous concrete that can be installed in rivers will be realized. Furthermore, since this porous concrete is formed in a block shape, it can be transferred or transported as a lump, and unlike the case of transporting powdery or granular concrete, it does not require time and effort such as loading on a pallet or a container. , Can be easily transferred and transported.

The aggregate made of zeolite according to the present invention (hereinafter, also referred to as “zeolite aggregate”) has a particle size of preferably 5 mm or more and 40 mm or less, and particularly preferably 5 mm or more and 30 mm or less. In particular, if a zeolite aggregate having a particle size of 10 mm or more is used, the porosity becomes high, and the removal rate of ammonia and the like can be increased. Further, if a zeolite aggregate having a particle size of less than 25 mm, particularly less than 10 mm is used, the bonding force between the aggregates is increased, and the compressive strength can be increased. Therefore, when purifying the water quality, the block shape after being put into the water area can be maintained for a long time.

The cement used to bond the zeolite aggregate is used in an amount of 4% or more and 35% or less, particularly preferably 5% or more and 25% or less in terms of volume ratio with respect to the zeolite which is the aggregate. It is desirable to do. By setting it to 4% by volume or more, it is possible to increase the bonding force between the zeolite aggregates and increase the compressive strength, while by setting it to 35% by volume or less, the porosity is increased and the exposed area of the zeolite aggregate is increased. It can be made larger.

As such cement, ordinary Portland cement, silica fume cement or the like may be used, but silica fume cement is preferably used. This is because the flow value of silica fume cement has the smallest effect on the continuous porosity. Therefore, in the case of silica fume cement, even when the flow value of the cement paste is small, it is possible to obtain porous concrete with a small amount of adhesion and a large continuous porosity.

Further, it is desirable that the cement for binding the zeolite aggregate is a cement paste formed by adding water to the cement. It is desirable that the water / cement ratio of this cement paste is 15% or more and 55% or less, particularly 20% or more and 50% or less. When the water / cement ratio is 15% or more, the zeolite aggregate can be reliably connected, and when it is 55% or less, the cement paste extends to the center of the zeolite aggregate filled in the mold. Can be inserted.

When a certain compressive strength is required, such as when installed in a river, it is desirable to further add an AE water reducing agent to the cement that binds the zeolite aggregate. It is desirable that the AE water reducing agent is blended in an amount of 0.5% by mass or more and 2.5% by mass or less, particularly 1.0% by mass or more and 2.0% by mass or less, based on the cement. .. By setting the amount of the AE water reducing agent to 0.5% by mass or more and 2.5% by mass or less with respect to the cement, the balance between the continuous porosity and the compressive strength when the porous concrete is formed into a block shape is balanced. , It can be optimized for installation in water such as rivers.

In the above-mentioned porous concrete according to the present invention, an aggregate made of zeolite is installed and filled in a predetermined amount in a mold, cement paste is poured over the aggregate, and excess cement paste is applied to the lower part of the mold and the mold. / Or it can be manufactured by flowing out from the side and hardening by leaving the cement paste only at the contact points between the aggregates.

That is, the porous concrete of the present invention has an aggregate filling step of filling a concrete mold with crushed zeolite as an aggregate, and a cement in which cement is dissolved in water from above the aggregate filled in the mold. It can be manufactured by a method for manufacturing porous concrete, which comprises a cement paste pouring process in which the paste is poured.

In the above-mentioned flowing step, the gap between the zeolite aggregates is not filled with the cement paste. Therefore, the bottom surface of the mold is formed in a net-like or porous shape, and in the cement paste pouring step, the poured cement paste flows out from the bottom surface and / or the side surface through the filled aggregates. It is desirable to do so.

In the porous concrete formed by the above method, the poured cement paste adheres to the contact points between the zeolite aggregates and hardens, so that the zeolite aggregates can be agglomerated to form a block. Since the poured cement paste does not wrap around the lower surface of each zeolite aggregate in the flowing direction, the zeolite is exposed on the lower surface. This results in a porous concrete with an increased exposed area of zeolite.

Further, the porous concrete of the present invention can also be produced by a compact method using crushed zeolite as an aggregate. However, in this case, it is desirable that any one or more surfaces are formed by cutting, polishing or dividing so that the zeolite as an aggregate is exposed.

In the porous concrete of the present invention, the zeolite used as the aggregate is crushed and is bonded by cement to form a block as a whole, and the crushed zeolite is hardened into a block by concrete. , One side is exposed. As a result, the exposed area of zeolite can be increased, and the purifying action of the water area and the atmosphere can be maximized.

Further, in the porous concrete, the zeolite used as the aggregate has a particle size of 5 mm or more and 20 mm or less, and the amount of cement used to bind the zeolite used as the aggregate is larger than that of the zeolite used as the aggregate. When it is 4% by volume or more and 35% by volume or less, it can be formed with a compressive strength that does not easily collapse even when installed in a water area such as a river, while stably increasing the porosity. Therefore, a porous concrete having continuous voids that can be provided with more stable quality is realized.

In the porous concrete according to the present invention, the cement that binds the aggregate made of zeolite is silica fume cement, and the cement has a water / cement ratio of 15% or more and 55% or less, and further, AE water reduction. When the agent is blended in an amount of 0.5% by mass or more and 2.5% by mass or less with respect to cement, it maximizes the adsorption effect of zeolite used as an aggregate and has sufficient strength. , Porous concrete using zeolite can be used.

Further, as a method for producing porous concrete using zeolite aggregate, there is an aggregate filling step of filling the mold with crushed zeolite as an aggregate, and watering cement from above the aggregate filled in the mold. Since it is a method of manufacturing porous concrete, which consists of a cement paste pouring process in which the cement paste melted in is poured over, the void ratio and compressive strength are almost constant, and stable quality porous concrete is used without applying a vibrator. Can be provided.

Then, in the method for producing porous concrete, the bottom surface of the formwork is formed in a net-like or porous shape, and in the cement paste pouring step, the poured cement paste passes between the filled aggregates. By forming the concrete so as to flow out from the bottom surface and / or the side surface, it is possible to produce porous concrete in which the compressive strength and the void ratio are controlled depending on the material and fluidity of the cement paste. In addition, the strength of the porous concrete and the exposure ratio of the zeolite aggregate can be changed depending on the order in which the cement paste is poured and the amount of the cement paste.

In the production of the porous concrete, it is not always necessary to use a formwork in which only the bottom surface is reticulated or porous, and other forms can be used. For example, at least one of the bottom surface and the side surface may be a box or bag shape formed in a net-like or porous shape in which gaps and holes are formed so that the cement paste that has been poured can flow out. By doing so, the exposed area of the zeolite can be further increased.

Therefore, according to the porous concrete according to the present invention, blocks are submerged in water areas where nitrogen and phosphorus are eutrophicated in scenic ponds, rivers, and lakes to purify the water quality. Polluted water can be circulated in contact with the block to purify the water area. Further, when the block made of porous concrete according to the present invention is manufactured with a strength and a size that cannot withstand the water area, it can be taken out and recycled, and cost reduction can be achieved.

In addition, by devising the formulation conditions for the block (for example, zeolite with a particle size of 10 mm to 20 mm is used as an aggregate, and ordinary Portland cement is used as the cement), the strength is inferior, but the water purification function is improved and the manufacturing cost is also reduced. Be done. The blocks formed in this way naturally collapse over time to become powder and are released into the basin, and the aggregate is natural zeolite, which has little effect on the natural world.

Further, the porous concrete block according to the present invention has a porous property in which microorganisms in the natural world can easily adhere to the block, and the water quality can be purified by the microorganisms. In the fish farming industry, pollution of the breeding tank by fish food and excrement affects the growth of fish, and water quality management requires a large amount of money. , The water quality of the aquarium can be maintained. In addition, purification of fish breeding aquariums in aquariums can be done at low cost.

Furthermore, by putting it in a wastewater treatment facility and submerging it in a reaction tank that removes ammonia, the load on the activated sludge required for nitric acid from ammonia can be reduced, and in addition to water, in breeding facilities such as pig farms. By forming a block of zeolite that adsorbs ammonia against the problematic odor of ammonia, it can be installed at the opening of a facility where odor leaks and used as a countermeasure against odor.

Schematic diagram showing the manufacturing process of the porous concrete block of this embodiment Graph showing the result of Experimental Example 1 Schematic diagram showing the experimental state of Experimental Example 3 Graph showing the result of Experimental Example 3 Graph showing the result of Experimental Example 3 Photograph showing the zeolite used in Experimental Example 4 Graph showing the result of Experimental Example 4 Graph showing the result of Experimental Example 5 Graph showing the result of Experimental Example 5 Graph showing the result of Experimental Example 6 Graph showing the result of Experimental Example 6 Graph showing the result of Experimental Example 6 Graph showing the result of Experimental Example 6 Graph showing the result of Experimental Example 6 Graph showing the result of Experimental Example 8

Hereinafter, embodiments of the porous concrete according to the present invention and a method for manufacturing the same will be described with reference to the drawings.

In the present embodiment, the surface of the zeolite aggregate 13 is not entirely covered with the cement paste 14 (that is, at least one of the surfaces is exposed), and the porous concrete 20 can secure a large porosity. Manufactured. That is, using the materials shown in the formulation conditions of Table 1 below, as shown in FIG. 1, the mold 10 was filled with the zeolite aggregate 13, and the cement paste 14 was poured over the zeolite aggregate 13.

（100mm×100mm×100mmのブロックの大きさとした場合）

(When the block size is 100 mm x 100 mm x 100 mm)

The zeolite used as the aggregate 13 had a particle size of 5 to 10 mm (Z-51 manufactured by Siegrite Co., Ltd.). Zeolites with a particle size of 10 to 20 mm (Z-120 manufactured by Siegrite Co., Ltd.) have a higher ammonia removal rate, but have a higher porosity and lower strength. In order to maintain the shape of the block afterwards, a particle size of 5 to 10 mm (Z-51 manufactured by Siegrite Co., Ltd.) was adopted.

Using the cement, admixture, and water shown in Table 1 above, the cement paste for solidifying the zeolite aggregate was produced by the following procedure.
First, the cement, water, and high-performance AE water reducing agent shown in Table 1 were placed in a kneading bowl and kneaded by hand for 30 seconds. The kneading pot was placed on the mixer, the kneading machine was slowed down to knead for 60 seconds, the kneading pot was removed from the mixer, and the cement was kneaded by hand for 30 seconds to scrape off the solidified cement. Then, the kneading bowl was placed in the mixer again, the mixer was speeded up, and the mixture was kneaded for 90 seconds. Before pouring, the mixture was thoroughly hand-kneaded or kneaded with the mixer at high speed.

Then, using the cement paste 14 described above, the porous concrete 20 is then manufactured. In the method for producing such porous concrete, as shown in FIG. 1, a mold 10 was used in which the side surface 11 was molded from plywood coated on the inner surface and the wire mesh 12 having a size of 5 mm was attached to the bottom. The zeolite used as the aggregate 13 is soaked in water for 24 hours or more in advance before being put into the mold 10, and the zeolite in water is placed on a sieve having an empty size of 5 mm 1 to 2 hours before making a block. It was spread out and the sieve was vibrated to remove water. Then, the zeolite remaining on the sieve was packed in a mold. At this time, no action such as vibrating the formwork is performed.

Then, the cement paste 14 produced by the above method was kneaded and poured over the aggregate 13 while being sprinkled evenly in a plane. The excess cement paste 14 that ran down was received by a vat 15 or the like installed below.

By hardening the porous concrete produced by the above method, the actual volume ratio of the aggregate of zeolite having a particle size of 5 mm to 10 mm is 60%, the cement paste is 40% by mass, the water / cement ratio is 24%, and the high-performance AE. As for the amount of water reducing agent used, porous concrete with cement mass x 1.5% was completed.

In the following examples, in order to confirm the characteristics of the porous concrete according to the above embodiment, the water quality purification effect was confirmed by comparison with the following porous concrete to be compared.

[Comparative porous concrete]
The porous concrete to be compared was manufactured by the conventional method using the materials shown in the formulation conditions in Table 2 below. That is, the aggregate made of zeolite and cement are mixed first so that the cement powder is sprinkled around the aggregate, and then water is mixed and the aggregates wrapped in the cement paste come into contact with each other. Porous concrete that formed a porous state was used.

（ポーラスコンクリート３Ｌの場合）

(In the case of porous concrete 3L)

[Experimental Example 1]
In this experimental example, the ammonia removal effect of the comparative porous concrete was confirmed.
That is, the concentration of ammoniacal nitrogen in the container containing polluted water with the porous concrete to be compared and the one without the block (reference) can be obtained as shown in FIG. Was confirmed from the materials presented by the Materials Society.

From this experiment, the ammonia removal effect of the comparative porous concrete was confirmed. However, according to this method, the circumference of the zeolite aggregate was almost completely covered with cement, and the contact between the water to be purified and the zeolite was small. In addition, there is a problem that the strength of the cement portion of porous concrete is insufficient.

[Experimental Example 2]
Ammonia adsorption capacity was tested as one of the indexes of water purification capacity of porous concrete according to this embodiment. In the test, the porous concrete according to the present embodiment and the porous concrete (conventional method) to be compared were placed in 300 mL of an ammonium chloride solution containing ammonium ions (about 4000 ppm), and the ammonium ions were measured 24 hours later. , The collection rate was calculated. The results are shown in Table 3 below.

本実施例の結果から、本実施の形態にかかるポーラスコンクリートはゼオライトがセメント分で覆われないことから、比較対象のポーラスコンクリートに対して1.6倍の吸着能力が高いことが確認できた。

From the results of this example, it was confirmed that the porous concrete according to the present embodiment has 1.6 times higher adsorption capacity than the comparative porous concrete because the zeolite is not covered with cement.

[Experimental Example 3]
In this experimental example, the water quality purification effect of porous concrete according to this embodiment was confirmed in a water tank. That is, as shown in FIG. 3, 10 blocks 20 (6 cm cubes) made of porous concrete according to the present embodiment were immersed in the circulation portion 31 of the aquarium 30, and water quality purification was confirmed in the aquarium in which the fish were bred. did. The water tank 30 contains the total nitrogen of nitrogen compounds (ammonia nitrogen, nitrate nitrogen, nitrite nitrogen) in the water tank (reference) in which the block 20 is not charged and the water tank (with the block) in which the block 20 is charged. The change in the concentration of phosphate ion was investigated. The results are shown in FIGS. 4 and 5.

In the reference, both ammoniacal nitrogen and nitrate nitrogen are rising, while the blocking ammoniacal nitrogen disappears in 3 weeks. It is considered that a biofilm is formed in the block and the purification ability by microorganisms is added. Phosphate ion rises with time in the reference, but when the porous concrete block according to this embodiment is installed, ammonia is adsorbed on the zeolite of the block, calcium of the cement component is desorbed, and calcium phosphate is formed. It is also considered to have the effect of reducing.

In this embodiment, with respect to the porous concrete according to the present embodiment, in order to confirm the compressive strength and the water purification effect due to the difference in the type and particle size of the aggregate, the water / cement ratio in the cement paste, and the mixing ratio of the water reducing agent. An experiment was conducted.

[Experimental Example 4]
In this experimental example, the difference in compressive strength and purification effect due to the difference in zeolite aggregate was confirmed.
Using zeolite from Yonezawa, Yamagata Prefecture, as an aggregate, a block was made from porous concrete to be compared, and a compressive strength test was conducted. As shown in FIG. 6, the zeolites used were (1) natural zeolite particle size 5 to 10 mm (manufactured by Siegrite Co., Ltd., Z51), and (2) natural zeolite particle size 10 to 20 mm (manufactured by Siegrite Co., Ltd., Z120). ), (3) Calcined zeolite particle size 10 to 20 mm (Zeocera, manufactured by Siegrite Co., Ltd.).

As a result, the block using Zeocera and Z120 lacked the strength of the cement part of the porous concrete, and the strength as a block was not sufficient.
In addition, using these blocks, changes in the quality of polluted agricultural water were confirmed. For this change in water quality, the total nitrogen and phosphorus contents at the start of measurement and the total nitrogen and phosphorus contents 28 days after the porous concrete block was put in (after treatment) were measured, and the amount of change was measured. Confirmed by. The result is shown in FIG.
From the results of this experiment, a tendency of decrease in total nitrogen and total phosphorus concentrations, which are indicators of eutrophication, was observed. Total nitrogen was highly reduced by Zeocera, and total phosphorus was reduced in all blocks.

[Experimental Example 5]
In this experiment, the difference in compressive strength and purification effect between zeolite aggregate and crushed stone aggregate was confirmed.
That is, a porous concrete block according to this embodiment using a natural zeolite particle size of 5 to 10 mm (Z51 manufactured by Siegrite Co., Ltd.) as an aggregate, and a crushed stone (fine aggregate) having a particle size of 5 to 10 mm as an aggregate. Was used to manufacture a porous concrete block manufactured by the same manufacturing method as in this embodiment, and a strength test was conducted. The result is shown in FIG.

In this experiment, even if a natural zeolite particle size of 5 to 10 mm (manufactured by Siegrite Co., Ltd., Z51) was used ^{as the aggregate, data of about 2} N / mm 2 was obtained, and a certain strength was confirmed as a concrete molded body. Was done.

In addition, a test piece obtained by crushing a porous concrete block according to the present embodiment produced by using a natural zeolite particle size of 5 to 10 mm (Z51 manufactured by Zeeklite Co., Ltd.) as an aggregate, a natural zeolite particle size of 5 to 10 mm (Zeekrite stock). Company-made, Z51) 300 g of each single test piece was placed in 15 L of polluted water and a water tank experiment was conducted. The change in the nitrogen compound component of the water quality after 5 days in this experiment is shown in FIG.

As shown in FIG. 9, the aggregate (test piece obtained by crushing the test piece) is changed to nitrite nitrogen and organic nitrogen, and the simple substance (natural zeolite alone) is changed to nitrate nitrogen, and the nitrification reaction proceeds. It was confirmed that there was.

In this example, regarding the porous concrete according to the present embodiment, it was confirmed that the water quality purification effect differs depending on the type of aggregate and the presence or absence of a thickener.
[Experimental Example 6]
In this experiment, a porous concrete block 10 cm x 10 cm x 10 cm with a water-cement ratio (C / W) of 45% was manufactured using the formulation shown in Table 4 below, and this was used as a water tank containing polluted water (internal volume: about). It was put into 20L) and the water quality changed.

The water purification effect of this porous concrete block on nitrogen compounds is shown in FIGS. 10 to 13.
In this experimental result, the water purification effect of the porous concrete block was reduced by the adsorption of ammonia. Therefore, the removal of ammonia was higher in Z120 than in Z51, and the concentration decreased in 0 kg without thickener than in 2 kg. Was there.

In addition, FIG. 14 shows the change in phosphoric acid in the different types of aggregates of Samples 1 to 4. From this result, phosphorus was removed in Z51. Since the removal of phosphorus is due to the reaction between the calcium content expelled from the zeolite and the calcium content eluted from the cement content, it is estimated that this amount is higher in Z51.

[Experimental Example 7]
In this experiment, the compressive strength of the porous concrete block using zeolite aggregate was confirmed. That is, in the porous concrete according to the present embodiment, the factors affecting the strength are the water-cement ratio and the continuous porosity, and the porosity decreases by increasing the thickener, but the compressive strength tends to increase. It was seen.

Therefore, in this experiment, a porous concrete block was manufactured by adjusting the type of aggregate (zeolite), the water-cement ratio, and the blending amount of the water reducing agent according to the contents shown in Table 5 below. Then, the passage time of the cement paste, the amount of adhesion of the cement paste, the continuous porosity, and the compressive strength were compared and examined by the following methods. The results are shown in Table 5 below. Ordinary Portland cement was used as the cement.

[Method of measuring transit time of cement paste]
The passage time of the cement paste was measured when the cement paste was poured during the preparation of the porous block test piece. The measuring method was to measure the time from the pouring of the cement paste to the start of dripping (passing time at the beginning of dripping) and the time from the start of dripping to the end of dripping (passing time at the end of dripping). The end of dripping was when the drips of cement paste did not dripping for 10 seconds.

[Method of measuring the amount of cement paste adhered]
The amount of cement paste adhered was measured at the time of preparing the porous block test piece. The measuring method was to measure the amount of cement paste input and the amount of cement paste that passed through the aggregate to determine the amount of cement paste that adhered to the aggregate.

[Continuous porosity measurement method]
For the continuous porosity of the porous block test piece, the air mass and the underwater mass of the test piece were determined, and the porosity was calculated using the following formula. The test procedure is shown below.
<Test procedure>
(1) Measure the dimensions (diameter x height) of the test piece using a caliper, and calculate the volume V.
(2) After the test piece is saturated in water for 24 hours or more after demolding, the mass W ₁ in water is measured. At that time, the test piece is rolled in water so that no air pool is formed in the test body at the time of measurement, and the air is sufficiently removed.
(3) Let it stand naturally for 24 hours under 20 ± 2 ° C and 60% relative humidity, and measure the _{air mass W 2.}
Calculation formula: Ar (%) = 1-((W _2- W ₁ ) / ρw) / V x 100
Ar: Continuous porosity, W ₁ : Mass of the test piece in water, W ₂ : Mass in the air after being left naturally for 24 hours
V: Volume of test piece, ρw: Density of water

[Compressive strength measurement method]
A test piece for compressive strength was prepared and measured. This test specimen for compressive strength is a method of removing excess cement paste by pouring the cement paste immediately after kneading from above after putting the aggregate into a cylindrical steel formwork (φ100 x 200 mm) with a wire mesh as the bottom plate. And said. The volume used in the calculation was the volume of the cylindrical steel formwork. The test piece was cement-capped on the upper surface, cured in the air for 24 hours, and then cured in water for 28 days. Three specimens were prepared for each combination. Then, unbonded capping was used for the compressive strength test piece of 28 days old, and the compressive strength was measured according to JIS A 1108.

As a result of this experiment, it was confirmed that the smaller the aggregate particle size, the more remarkable the effect of the thickener. In addition, the amount of cement paste adhered increased as the water-cement ratio decreased, but it was confirmed that the amount of cement paste adhered did not differ much depending on the presence or absence of the thickener. In addition, the smaller the aggregate particle size, the larger the amount of paste adhered.

There was not much difference in the continuous porosity depending on the use of the thickener, and the smaller the aggregate particle size, the smaller the continuous porosity. In this experiment, the compressive strength of the porous concrete block was 0.16 N / mm ^{2 to} 0.39 N / mm ² , and the compressive strength of the cement paste tended to decrease with the use of the thickener.

[Experimental Example 8]
In this experiment, the flow, flow time, adhesion amount, continuous void ratio, compressive strength, and bending strength of the porous block when the cement was changed were measured by the following methods, and the continuous void ratio and compressive strength were measured by the following methods. Confirmed the relationship.
Porous block using ordinary Portland cement has a continuous porosity of 38.2% and a compressive strength of 0.49 N / mm ² . Even when ordinary Portland cement was used, the compressive strength tended to decrease as the continuous porosity of the porous block increased. From this, silica fume cement (samples: SF1 to SF4) was prepared as a cement suitable for production in order to improve the continuous porosity and compressive strength of the porous block, and the flow, flow time, adhesion amount, and porous block of the cement paste were prepared. The continuous porosity, compressive strength, and bending strength of the were measured.
The flow, flow time, adhesion amount, continuous porosity of porous block, and compressive strength of cement paste were measured by the following methods, and the relationship between continuous porosity and compressive strength was confirmed. Zeolite Z-51 was used as the aggregate. The formulation is as shown in Table 6, and the results are shown in Table 6 and FIG.

[Cement paste flow]
In the flow test of cement paste, referring to JIS R5201, only the flow value with 0 vibration was measured on the slump plate without using the flow table. The cement paste used in the flow-down time measurement test was used. The paste after the flow measurement was used in the production of a specimen for strength test of cement paste. The flow test procedure is shown below.
(1) Wipe the slump board with a dry cloth and place the flow cone in the center.
(2) Fill 1/2 layer of the flow cone with the mixed cement paste and poke it over the entire surface 15 times with a stick.
(3) Fill the remaining 1/2 layer with cement paste and apply 15 times in the same way.
(4) Make up for the shortage in the flow cone and level the surface.
(5) Remove the flow cone upward, and measure in 1 mm units using a tape measure in the direction in which the maximum diameter after the cement paste spreads is recognized and in the direction perpendicular to it.
This test is performed twice, and the average value is used as the flow value.

[Cement paste flow time]
The flow time of the cement paste was determined by the following procedure using a J14 funnel with reference to "Fluidity test method for filled mortar (draft) (JSCE-F541-2013)".
(1) Set the funnel on a tripod and let water pass through it to get it wet. Block the outlet of the funnel and inject cement paste into the funnel.
(2) Prepare a receiving container under the outlet of the funnel, inject cement paste to the upper end, and then open the outlet.
(3) Use a stopwatch to measure the time from the point when the cement paste begins to flow down from the outlet until the cement paste flow suddenly becomes thin.
The measurement was performed twice by the above method, and the average value was taken as the flow time.

[Amount of cement paste adhered]
The mass of 100 ml of the cement paste was measured in a measuring container, and the amount of adhesion was measured by subtracting the mass attached to the container after pouring it over the aggregate and the mass dropped from the wire mesh. The procedure is as follows.
(1) Measure the mass of the cement paste before pouring.
(2) Pour the cement paste onto the block to remove excess paste.
(3) After pouring, measure the mass of the paste adhering (residual) to the container.
(4) Measure the mass of the excess cement paste that has flowed down.
(5) The amount of adhesion is measured by subtracting the mass attached to the container and the mass that has flowed down from the original mass.

The density (g / ml) of the cement paste was 2.20 g / ml for samples SF1 and SF2, and 2.08 g / ml for samples SF3 and SF4.

[Continuous porosity of porous blocks]
The continuous porosity measurement was performed using a specimen of 60 × 60 × 60 mm. After demolding, it was cured in water for 1 day or more, and mass measurement in water and mass measurement in air were performed using 3 specimens for each pattern. The volume of the specimen used for the measurement was calculated by measuring the length, width, and height using a caliper. The procedure is as follows.
(1) Measure the dimensions (diameter x height) of the specimen using a caliper, and calculate the volume V.
(2) After the specimen is saturated in water for 24 hours or more after demolding, the mass W1 in water is measured. At that time, the specimen is rolled in water so that no air pool is formed in the specimen during the measurement, and the air is sufficiently removed.
(3) The specimen is taken out of water and left to stand for 15 minutes, and the air mass W2 is measured.
After measuring the mass in water and the mass in air, the porosity is calculated using the following formula. The average value calculated by measuring with three specimens for one pattern is defined as the continuous porosity.
Ar (%) = {1− ((W2-W1) / ρw) / V} × 100
Ar: Continuous porosity, W1: Mass of specimen in water, W2: Mass in air after being left to stand for 15 minutes
V: Volume of specimen, ρw: Density of water

[Compressive strength of porous block]
This test complies with JIS A 1108, and the diameter of the specimen is measured by measuring a total of 6 points with a caliper at 3 points in two orthogonal directions (upper, lower, and center of the specimen). The compressive strength is measured using an Amsler-type compressive strength tester. The bottom surface of the specimen is unbonded capped and installed in a compression tester. When conducting the test, a load is applied so that the increase in compressive stress is 0.6 ± 0.4 N / mm2 per second so as not to give an impact to the specimen. The compressive strength was determined by dividing the maximum load obtained by the test by the cross-sectional area obtained from the average diameter of the specimen. In the strength test, three specimens were tested for each pattern, and the average value was taken as the compressive strength.

From this experiment, the optimum compounding conditions for obtaining the desired standard continuous porosity of porous block: 39.6%, compressive strength: 0.98N / mm ² (age 42 days) are cement type silica fume cement, water cement ratio 24. %, And the amount of high-performance AE water reducing agent used was 1.5%.

The porous concrete according to the present invention can be used to obtain a purification effect in a water area or an atmosphere.

10 formwork
11 side
12 wire mesh
13 Zeolite (aggregate)
14 Cement paste
15 bat
20 Porous concrete

Claims (5)

In porous concrete made of zeolite as an aggregate,
The zeolite used as the aggregate is crushed and is bonded by cement to form a block as a whole.
The cement adheres to the contact points between the crushed zeolites and hardens, and the crushed zeolites form a block as a mass.
Each crushed zeolite that is hardened into blocks by concrete is porous concrete in which the zeolite is exposed without cement wrapping around on one side.
The zeolite used as the aggregate has a particle size of 5 mm or more and 30 mm or less.
The porous concrete according to claim 1, wherein the amount of cement used to bind the zeolite used as the aggregate is 4% by volume or more and 35% by volume or less with respect to the zeolite as the aggregate.
The cement that binds the aggregate made of zeolite is silica fume cement.
The cement has a water / cement ratio of 15% or more and 55% or less.
The porous concrete according to claim 1 or 2, wherein the AE water reducing agent is blended in an amount of 0.5% by mass or more and 2.5% by mass or less with respect to the cement.
The voids existing between the zeolites solidified in the block shape are continuous.
The continuous porosity calculated by the following formula (1) is 31.7% or more.
Equation (1)
Ar (%) = {1− ((W2-W1) / ρw) / V} × 100
Ar: Continuous porosity, W1: Mass of specimen in water, W2: Mass in air after being left to stand for 15 minutes
V: Volume of specimen, ρw: Density of water
Compressive strength according to JIS A 1108 is 0.16N / mm ² ~ 0.39N / mm ² The porous concrete according to any one of claims 1 to 3.
A method for producing porous concrete using zeolite as an aggregate.
The zeolite used as the aggregate is in the form of crushed material, and the aggregate filling step of filling the mold with the crushed zeolite as the aggregate.
From above the aggregate filled in the mold frame, cement and flow over the cement paste dissolved in water, crushed zeolite in the mold joined by cement, pouring cement paste is formed in a block shape as a whole Ri Do and a step,
In the cement paste pouring step, the sprinkled cement paste is allowed to flow out from the bottom surface and / or the side surface of the mold through the filled aggregates, thereby causing the crushed zeolite to flow out below the pouring direction of the crushed zeolite. without it flowing around the surface, Ru expose the lower surface of the pulverized zeolite compacted into blocks by concrete manufacturing method of porous concrete.

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