JPWO2019172349A1 - Acid-resistant concrete, precast concrete, and method for producing acid-resistant concrete - Google Patents

Abstract

Provide highly durable acid resistant concrete. For this reason, acid-resistant concrete is mixed with water, industrial by-products, alkali stimulating materials, expansive materials, fine aggregates, coarse aggregates, and high-performance water reducing agents, and compacted by centrifugal force molding. Manufactured. Industrial by-products include fly ash, blast furnace slag fine powder, and silica fume, and alkaline stimulants include slaked lime. Industrial by-products may include sewer sludge incineration ash. Further, it may be steam-cured after molding and the pre-positioning time may be 1.5 hours or more.

Description

The present invention relates to acid resistant concrete, precast concrete, and a method for producing acid resistant concrete.

In recent years, sewer pipes with a service life of more than 50 years have been repaired and maintained. Further, even in the case of a sewer pipe having a service life of less than 50 years, “sulfuric acid deterioration” in which the pipe is corroded by hydrogen sulfide is becoming serious. If this is severe, there have also been reports of cases of road crashes. Therefore, a highly durable sewer pipe having a service life of 100 years has been demanded, and has been attracting attention as a new era need.

Here, according to Patent Document 1, it is a coated mortar that can protect concrete and mortar, and has excellent plastering workability, pumpability, sag resistance, adhesiveness, shape dimension stability, and crack resistance, Furthermore, a corrosion resistant mortar composition having excellent acid resistance is described. This corrosion-resistant mortar composition is substantially free of a cement polymer, (A) cement, (B) blast furnace slag fine powder, (C) fly ash, (D) expansive material, and (E). A specific aggregate containing calcium and aluminum as chemical components and (F) a thickener are contained in a mortar composition in a specific ratio, and further (G) a water reducing agent, (H) a defoaming agent, (I). ) One or more components selected from alkali metal carbonates or formates, (J) alkali metal sulfates, and (K) one or more components selected from organic fibers.

JP, 2017-132667, A

Ishitoshi Toshiaki, Uzawa Masami, Yamaguchi Shin, Maeda Masahiro, Ikawa Hideki, Hosaka Shigeru, “Strength characteristics and microstructural changes of mortar mixed with sewage sludge incinerated ash under various curing conditions, materials, Journal of Society of Materials Science”. Japan, 2017, Vol. 66, No. 10, p. 752-757.

However, the corrosion-resistant mortar composition of Patent Document 1 needs to be separately applied to the formed concrete product.

The present invention is made in view of such a situation, and an object of the present invention is to solve the above-mentioned problems and to provide acid-resistant concrete that does not require coating or the like.

The acid-resistant concrete of the present invention contains water, an industrial by-product, an alkali stimulating material, an expanding material, a fine aggregate, a coarse aggregate, and a high-performance water reducing agent, and the mixture is compacted by centrifugal molding. It is characterized by being manufactured.
The acid resistant concrete of the present invention is characterized in that the industrial by-products include fly ash, blast furnace slag fine powder, and silica fume, and the alkali stimulant includes slaked lime.
Acid resistance concrete of the present invention, the water 170 kg / m ^3, the fly ash to 207kg / m ^3, the blast furnace slag to 207kg / m ^3, the silica fume to 30kg / m ^3, the slaked lime 20 kg / m ^3, wherein the expandable material ^{30kg / m 3, 639kg / m} 3 the fine aggregate, the coarse aggregate 959kg / m ^3, and 5.434kg / m ³ the superplasticizer as a standard formulation, In weight percent, the water is 90 to 105%, the fly ash is 10 to 110%, the blast furnace slag fine powder is 90 to 190%, the silica fume is 50 to 130%, the slaked lime is 50 to 200%, and the expansion is performed. 60 to 130% of the material, 80 to 125% of the fine aggregate, 80 to 125% of the coarse aggregate, and 50 to 150% of the high-performance water reducing agent.
Acid resistance concrete of the present invention, the water 170 kg / m ^3, the fly ash to 207kg / m ^3, the blast furnace slag to 207kg / m ^3, the silica fume to 30kg / m ^3, the slaked lime 20 kg / m ^3, wherein the expandable material ^{30kg / m 3, 639kg / m} 3 the fine aggregate, the coarse aggregate 959kg / m ^3, and 5.434kg / m ³ the superplasticizer as a standard formulation, In weight percent, the water is 90 to 105%, the fly ash is 10 to 110%, the blast furnace slag fine powder is 90 to 190%, the silica fume is 50 to 130%, the slaked lime is 50 to 500%, and the expansion is performed. 60 to 130% of the material, 80 to 125% of the fine aggregate, 80 to 125% of the coarse aggregate, and 50 to 150% of the high-performance water reducing agent.
Acid-resistant concrete of the present invention, water, industrial by-products, alkali stimulating material, expansive material, fine aggregate, coarse aggregate, and a high-performance water reducing agent are blended, manufactured by vibration molding, Industrial by-products include fly ash, blast furnace slag fine powder, and silica fume, the alkali stimulant includes slaked lime, the water 170 kg/m ³ , the fly ash 207 kg/m ³ , the blast furnace slag fine powder. 207kg / m ^3, the silica fume to 30kg / m ^3, the slaked lime 20 kg / m ^3, the expansion member 30kg / m ^3, the fine aggregate to 639kg / m ^3, the coarse aggregate 959kg / m ^3, And with the high-performance water-reducing agent as a standard formulation of 5.434 kg/m ³ , the weight percentage of the water is 90 to 105%, the fly ash is 10 to 110%, and the blast furnace slag fine powder is 90 to 190%. , 50 to 130% of the silica fume, 50 to 500% of the slaked lime, 60 to 130% of the expansive material, 80 to 125% of the fine aggregate, 80 to 125% of the coarse aggregate, and the high performance. The water reducing agent is blended at a ratio of 50 to 150%.
The acid-resistant concrete of the present invention is characterized in that, as the industrial by-product, 26 kg/m ³ of sewer sludge incineration ash is used as a standard composition, and the sewer sludge incineration ash is compounded in a weight ratio of up to 200%. ..
The acid-resistant concrete of the present invention is characterized in that it is steam-cured after molding, and the pre-treatment time of the steam curing is 1.5 hours or more.
Acid-resistant concrete of the present invention, water, industrial by-products, alkali stimulating material, expansive material, fine aggregate, coarse aggregate, and a high-performance water-reducing agent are blended, placed in the field construction, The industrial by-products include fly ash, blast furnace slag fine powder, and silica fume, the alkali stimulant includes slaked lime, the water 170 kg/m ³ , the fly ash 207 kg/m ³ , the blast furnace slag fine powder. the 207kg / m ^3, the silica fume to 30kg / m ^3, the slaked lime 20 kg / m ^3, the expanding material to ^{30kg / m 3, 639kg / m} 3 the fine aggregate, the coarse aggregate 959kg / m ³ , And the high-performance water reducing agent as a standard composition of 5.434 kg/m ³ , and in weight percent, the water is 90 to 105%, the fly ash is 10 to 110%, and the blast furnace slag fine powder is 90 to 190%. %, the silica fume 50 to 130%, the slaked lime 50 to 500%, the expansive material 60 to 130%, the fine aggregate 80 to 125%, the coarse aggregate 80 to 125%, and the high The performance water reducing agent is blended in a proportion of 50 to 150%, and as the industrial by-product, the sewer sludge incineration ash 26 kg/m ³ is used as a standard formulation, and the weight ratio of the sewer sludge incinerator ash is 200%. It is characterized by doing.
The precast concrete of the present invention is characterized by being produced from the acid resistant concrete.
The precast concrete of the present invention is characterized by being a sewer pipe.
The acid-resistant concrete production method of the present invention comprises water, an industrial by-product, an alkali stimulating material, an expansive material, a fine aggregate, a coarse aggregate, and a high-performance water reducing agent, and the mixture is compacted by centrifugal molding. It is characterized in that it is subjected to vibration molding or is placed on site.

According to the present invention, water, an industrial by-product, an alkali stimulating material, an expansive material, a fine aggregate, a coarse aggregate, and a high-performance water reducing agent are mixed and manufactured by compaction by centrifugal molding. By doing so, it is possible to provide acid-resistant concrete with a long service life without the need for coating or the like.

1 is a photograph showing a slump flow of the present mixture according to Example 1 of the present invention. 1 is a photograph of the appearance and centrifugal molding of a centrifugally cured product according to Example 1 of the present invention. It is a graph which shows the setting time of this mixture which concerns on Example 1 of this invention. It is a graph which shows the change of the compressive strength of the hardening body of the vibration molding which concerns on Example 1 of this invention. It is a graph which shows the change of the compressive strength of the hardening body of the centrifugal molding which concerns on Example 1 of this invention. It is a graph of the strength ratio of the vibration molding to the centrifugal molding according to Example 1 of the present invention. 3 is a photograph of a vibration-molded cured product according to Example 1 of the present invention after a sulfuric acid resistance test. It is a graph which shows the result of the sulfuric acid resistance test which concerns on Example 1 of this invention. 1 is a photograph of a centrifugally molded cured product according to Example 1 of the present invention after a sulfuric acid resistance test. It is a graph which shows the result of the sulfuric acid resistance test which concerns on Example 1 of this invention. It is a graph which shows the relationship of an addition rate and compressive strength about standard mix|blending of this mixture which concerns on Example 1 of this invention. It is a photograph after a sulfuric acid resistance test according to Example 2 of the present invention. It is a graph which shows the result of the sulfuric acid resistance test which concerns on Example 2 of this invention. It is a graph which shows the result of the strength development test which concerns on Example 2 of this invention. It is a graph which shows the result of the strength development test which concerns on Example 2 of this invention. It is a graph which shows the result of the strength development test which concerns on Example 2 of this invention. It is a graph which shows the result of the strength development test which concerns on Example 2 of this invention. It is a graph which shows the result of the compressive strength test of the cylindrical hardened body and the centrifugal hardened body which concern on Example 2 of this invention. It is a graph which shows the result of the compressive strength test of the cylindrical hardened body and the centrifugal hardened body which concern on Example 2 of this invention. It is a graph which shows the result of the compressive strength test by the addition amount of the calcium hydroxide which concerns on Example 2 of this invention. It is a conceptual diagram of the simple promotion neutralization test apparatus which concerns on Example 2 of this invention. It is a graph which shows the result of the neutralization suppression effect test which concerns on Example 2 of this invention. It is a photograph of the neutralization suppressing effect test according to Example 2 of the present invention. It is a graph which shows the result of the compressive strength test of the actual product of the vibration-molded cylindrical hardened body which concerns on Example 2 of this invention. It is a flowchart which shows the manufacturing process of the fume pipe which concerns on Example 2 of this invention. It is a photograph of the external pressure test of the actual product of the centrifugally hardened body according to Example 2 of the present invention. It is a graph which shows the external pressure test result which concerns on Example 2 of this invention. It is a graph which shows the external pressure test result which concerns on Example 2 of this invention.

<First embodiment>
The inventors of the present invention have carried out earnest experiments and developments aiming at a highly durable sewer pipe which has excellent acid resistance such as sulfuric acid resistance and can be expected to have a service life of 100 years, and has completed the present invention. It was The acid-resistant cement of the present embodiment does not use Portland cement at all, and the industrial by-product is a hardened body using centrifugal molding, and can be applied to a concrete product requiring high durability.

Hereinafter, embodiments of the acid resistant concrete of the present invention will be described.
The acid-resistant concrete of the present embodiment contains water, an industrial byproduct, an alkali stimulating material, an expansive material, a fine aggregate, a coarse aggregate, and a high-performance water reducing agent, and is compacted by centrifugal force molding. It is characterized by being manufactured by.

Of these, the water used for the acid-resistant concrete of the present embodiment is not particularly limited and may be tap water. The pH and the like of water according to this embodiment are also arbitrary.

Further, the industrial by-product of the acid-resistant concrete of the present embodiment is characterized by containing fly ash, blast furnace slag fine powder, and silica fume.

The fly ash according to the present embodiment is a porazon coal ash (fly ash) for concrete that is collected by a dust collector for burning pulverized coal of coal in a thermal power plant. As the fly ash according to the present embodiment, for example, fly ash type II or a similar product thereof defined by JIS A 6201, having a density of about 2.20 g/cm ³ is suitable. Since the main components of fly ash are silica and alumina, they are hardened by a pozzolanic reaction that produces calcium silicate hydrate and the like by an alkali stimulating material.

Further, the blast furnace slag fine powder according to the present embodiment is a blast furnace slag fine powder produced as a by-product in the pig iron manufacturing process. This blast furnace slag fine powder is preferably, for example, one having a specific surface area of 4000 in fineness defined by JIS A 6206. Further, it is preferable that the density is about 2.91 g/cmg/cm ³ . The ground granulated blast furnace slag is also hardened by the "latent hydraulic property" in which calcium silicate hydrate and calcium aluminate hydrate are produced and hardened by the alkali stimulant.

The silica fume according to the present embodiment is mostly amorphous and spherical silica (SiO ₂ ) collected as dust in the exhaust gas from the arc type electric furnace. It is preferable to use a silica fume having a density of about 2.30 g/cm ³ defined by JIS A 6207. Silica fume is preferably used for densification and improvement of strength of the cured product after centrifugation.

In addition to this, the industrial byproduct of the present embodiment may further include sewer sludge incineration ash. As this sewage sludge incineration ash, it is preferable to use "super ash" as described in Non-Patent Document 1 in which the particle size of sewage sludge incineration ash is adjusted.

The acid resistant concrete of the present embodiment preferably contains slaked lime as an alkali stimulating material. As the slaked lime, for example, it is preferable to use calcium hydroxide (Ca(OH) ₂ ) corresponding to JIS R9001 special issue. The density of slaked lime is preferably about 2.30 g/cm ³ . This alkali stimulant allows the fly ash and blast furnace slag fine powder to be hardened without using any conventional Portland cement.

In addition, the expansive material according to the present embodiment is a powdery substance that expands when water is supplied and has a property of reducing cracks due to drying shrinkage. Examples of the expansive material of the present embodiment include a lime-based expansive material, an ettringite-based (calcium sulphoaluminate-based) expansive material, and an ettringite-quicklime-based expansive material. Of these, in the present embodiment, it is preferable to use a lime-based expansive material as the expansive material. In addition, the expansive material is preferably one that conforms to the quality specified in Japanese Industrial Standard JIS A 6202 or the like, for example.

Further, as the fine aggregate according to the present embodiment, general fine aggregate such as crushed sand can be used. This fine aggregate corresponds to JIS A 5005 crushed sand (hard sandstone), and preferably has a density of about 2.62 g/cm ³ . As the fine aggregate, it is also possible to use slag-based aggregate, for example, fine aggregate produced from granulated slag of blast furnace, electric furnace oxidized slag aggregate, and the like.

Further, as the coarse aggregate according to the present embodiment, general coarse aggregate such as sandstone can be used. This coarse aggregate corresponds to JIS A 5005 crushed stone 2005 (hard sandstone), for example, and preferably has a density of about 2.67 g/cm ³ .

Further, the superplasticizer of the present embodiment is a chemical admixture that significantly reduces the unit water amount without affecting the consistency or significantly increases the slump without affecting the unit water amount. The high-performance water reducing agent of the present embodiment corresponds to JIS A 6204, for example, and it is preferable to use a polycarboxylic acid-based agent having a density of about 1.00 g/cm ³ .

Further, the acid-resistant concrete of the present embodiment includes water 170 kg/m ³ , fly ash 207 kg/m ³ , blast furnace slag fine powder 207 kg/m ³ , silica fume 30 kg/m ³ , slaked lime 20 kg/m ³ , expansive material 30 kg/m ³ . ³ , the fine aggregate 639 kg/m ³ , the coarse aggregate 959 kg/m ³ , and the high-performance water reducing agent 5.434 kg/m ³ are used as standard formulations.

Among them, it is preferable to mix 90 to 105% of water with 100% by weight of the standard mixture. That is, it is preferable to blend water ^{150kg / m 3 ~175kg / m 3} . With this composition, the sludge water is discharged well. On the other hand, when it is 90% or less, it becomes non-sludge, the centrifugal formability is lowered, and the final strength of the concrete-formed product is lowered. If it is 105% or more, the amount of sludge water increases and the strength decreases.

Similarly, fly ash is preferably blended in a proportion of 10 to 110%. Among these, although the strength gradually increases as the blending amount decreases, the use amount of the blast furnace slag fine powder increases, so it is preferable to set the lower limit to about 10%. Further, if it is blended in an amount of 110% or more, the strength is lowered, which is not preferable.
Further, the blast furnace slag fine powder is preferably blended in a proportion of 90 to 190%. Here, if the blending amount is decreased, the amount of fly ash increases and the strength decreases, so it is preferable to set the lower limit to about 90%. On the contrary, although the strength gradually increases as the usage amount increases, the amount of fly ash decreases, so it is preferable that the upper limit is about 190%.
Further, the super ash is preferably blended in a ratio of 0 to 200%. That is, it may be 0% without use, and the strength of the cured product is improved by reducing the blending ratio. On the other hand, if it is blended in an amount of more than 200%, the strength of the cured product will be significantly reduced, which is not preferable.
Moreover, it is preferable to mix silica fume in a ratio of 50 to 130%. With this composition, it becomes possible to realize the densification of the cured product after centrifugation and the improvement in strength. If it is less than 50%, the fragile layer on the inner surface disappears, but densification and strength improvement cannot be realized. Further, if it is blended in an amount of more than 130%, the brittle layer on the inner surface of the cured product increases, the performance as a sewer pipe deteriorates, and the strength also does not improve.
That is, as the mixing ratio of the industrial by-product of the present embodiment, silica fume is mixed with fly ash and blast furnace slag fine powder as the main components. Further, super ash may or may not be blended.

Further, slaked lime is preferably blended at a ratio of 50 to 200%. If it is less than 50%, the strength is lowered, which is not preferable. The strength is not improved even if the content is more than 200%. However, as described in the second embodiment described later, when slaked lime is blended in an amount of more than 200%, a neutralization suppressing effect can be obtained.
Further, the expansive material is preferably blended in a proportion of 60 to 130%. If it is less than 60%, the effect of preventing shrinkage cracking becomes insufficient. Even if it is more than 130%, the effect of preventing shrinkage cracking is not improved.
Further, it is preferable that the fine aggregate is mixed in a ratio of 80 to 125%. When it is less than 80%, the amount of fine aggregate is small and the amount of coarse aggregate is excessive, so that the surface of the cured body becomes rough and the strength is lowered, which is not preferable. When it is more than 125%, the amount of fine aggregate and water increases and the strength decreases, which is not preferable.
Further, the coarse aggregate is preferably blended in a ratio of 80 to 125%. If it is less than 80%, the amount of fine aggregate and water increases and the strength decreases, which is not preferable. When it is more than 125%, the amount of coarse aggregate is excessive and the amount of fine aggregate is small, the surface of the cured body becomes rough, and the strength is lowered, which is not preferable.
Further, the high performance water reducing agent is preferably blended in a ratio of 50 to 150%. If it is less than 50%, the amount of water increases and the strength of the product decreases, which is not preferable. If it is more than 150%, it is an excessive addition, the fluidity becomes excessive, the setting retardation further occurs, the strength decreases, and the cost increases, which is not preferable. Further, in the present embodiment, it is preferable that the high-performance water reducing agent is used by substituting and replacing water.

Further, the acid resistant concrete according to the present embodiment is preferably compacted by centrifugal force molding. In this centrifugal force molding, a mixture of water, industrial by-product, alkali stimulant, expansive material, fine aggregate, coarse aggregate, and high-performance water reducing agent (hereinafter, simply referred to as “mixture”) mixed in the above proportions. Is filled in a centrifugal molding mold, the mold is rotated at high speed on a molding machine, and centrifugal force is used to finally compact it at an acceleration of about 30 to 50 G, and excess water is discharged as sludge water. At this time, the acceleration may be increased in several steps to perform compaction so that the excess water is appropriately drained and compacted. At this stage, for example, 5G, 15G, and 35G are compacted at a rate of 1 minute, 1 minute, and 7 minutes, respectively. By producing by compaction by centrifugal molding in this way, the acid-resistant concrete according to the present embodiment enhances not only the strength but also the acid resistance, further shortens the steam curing time, and has a high-performance sewer pipe. Can be manufactured.

Further, the acid resistant concrete of the present embodiment is characterized in that it is steam-cured after molding, and the pre-treatment time of the steam curing is 1.5 hours or more. Precast concrete may be steam-cured in order to shorten the time until demolding and increase production efficiency. In this case, it is preferable to adjust the steam curing conditions such as pre-positioning time, rising temperature (heating), maximum temperature, holding time, and cooling method depending on the target product and the compounding conditions. Among these, the pre-position time is the time from the pouring of water to the start of temperature rise.
In the present embodiment, for example, the preheating time is kept at 1.5 to 4 hours, the temperature rise is kept at 15 to 25° C./hour, 60 to 75° C. for 3 to 5 hours or more, and then the temperature is gradually increased at the test room temperature. The condition of cooling and curing in air is used. By steam curing under such conditions, the setting and hardening (strength manifestation) of the mixture can be accelerated and the production efficiency can be improved.
Here, in the steam curing of the mixture of the present embodiment, the influence of the pretreatment time is particularly large. As will be described below, by performing centrifugal force molding, it is possible to produce concrete having sufficient strength and excellent acid resistance even if the pre-positioning time is 1.5 hours or more, even if it is less than 6 hours. It will be possible.

The slump flow of the acid-resistant concrete according to this embodiment is preferably about 650±50 mm. That is, the fresh property of the mixture of the present embodiment is a high flow type. This makes it possible to improve the filling property into the mold during molding, smoothly discharge the excess water as sludge water, and obtain a favorable compaction effect. Further, the weight ratio of water to the mixture (hereinafter, simply referred to as "water powder ratio") is about 20 to 60%.

In addition, the air content of the acid resistant concrete according to the present embodiment is preferably 2.0±1.5%, that is, 0.5 to 3.5%. This makes it possible to obtain desired strength while improving workability.
Further, in the present embodiment, this air amount can be adjusted by an air amount adjusting agent such as an AE (Air Entraining) agent. Examples of this AE agent include various anionic, cationic, nonionic, and amphoteric surfactants. Examples of the anionic surfactant include resin-based, alkylbenzene sulfonic acid-based, and higher alcohol ester-based surfactants. In the present embodiment, it is particularly preferable to use a modified rosin acid compound-based anionic surfactant. Note that it is also possible to use an AE water reducing agent having both properties of an AE agent and a water reducing agent.

Further, in the acid resistant concrete according to the present embodiment, fibers or the like may be mixed. Examples of the fibers and the like include fibrous substances such as vinylon fibers, acrylic fibers, and carbon fibers. In addition, zeolite, fine silica powder, calcium carbonate, clay minerals such as bentonite, gypsum, calcium silicate and the like may be appropriately mixed.

Further, in the acid-resistant concrete according to the present embodiment, in addition, a fluidizer, a retarder, a waterproof admixture, a moisture-proof admixture, a foaming agent, a thickener, an antifreezing agent, a colorant, a workability enhancer, an anti-proof agent. It is possible to appropriately add a soothing agent, a defoaming agent, a setting regulator, a shrinkage reducing agent, a cement hardening material, a polymer emulsion and the like.

Further, the acid resistant concrete according to the present embodiment is preferably used for manufacturing precast concrete. The precast concrete is preferably a fume tube. In addition, the fume pipe can be used as a highly durable sewer pipe.
By configuring as described above, the acid resistant concrete according to the present embodiment can exhibit sufficient acid resistance capacity. In addition, it is possible to improve the manufacturing efficiency when manufacturing concrete products in a dedicated factory. Therefore, with the acid-resistant concrete according to the present embodiment, it is possible to particularly preferably manufacture a sewer pipe.
Further, conventional sewer pipes include fume pipes, ceramic pipes, vinyl chloride pipes, and the like, and each sewer pipe has its intended use. On the other hand, since the precast concrete according to the present embodiment has high durability, it can be used even in a place where a ceramic pipe or the like needs to be used.

With the above configuration, the following effects can be obtained.
Conventional sewer pipes are mainly reinforced concrete pipes called fume pipes. Such reinforced concrete and mortar are composed of water, cement and aggregate, and harden by hydration reaction. For this reason, when used in a sewer pipe, "sulfuric acid deterioration" in which the inside of the pipe is corroded by hydrogen sulfide is serious, and it takes time to repair. Hume pipes have a service life of about 50 years, and in recent years, maintenance and renewal of the sewer pipes that have become widespread during the period of high growth in the Showa era have been carried out. Even when the service life of the fume pipe is less than 50 years, hydrogen sulfide generated in the pipe causes the sewer pipe to be corroded and deteriorated (sulfuric acid deterioration), and when this is severe, there are cases in which road collapse occurs.
However, it has been costly to apply the mortar described in Patent Document 1 or a material such as sulfuric acid resistant ordinary Portland cement to this maintenance. Therefore, there has been a demand for acid-resistant concrete, which is a highly acid-resistant cured product.
On the other hand, the acid-resistant concrete of the present embodiment is a conventional sulfuric acid-resistant ordinary Portland cement by using a mixture containing mainly an industrial by-product containing fly ash and and blast furnace slag fine powder, and an alkali stimulant. Chemical resistance is improved and acid resistance can be increased.
Specifically, as shown in Example 1 described later, in a sulfuric acid resistance test of immersing in a 5% concentration sulfuric acid aqueous solution for 28 days, the sulfuric acid resistance (mass The rate of change) was -32%, and severe sulfuric acid deterioration occurred. On the other hand, in the test piece obtained by vibration-molding the acid-resistant concrete of the present embodiment, the hardened body was in a substantially healthy state although a slight expansion occurred at +1.2%.

Further, the acid-resistant concrete of the present embodiment is subjected to centrifugal molding to be densified and restrained, so that expansion such as vibration molding does not occur and durability can be further improved.
As an effect of this centrifugal molding, as shown in Example 1 described later, the hardened body obtained by centrifugal molding of sulfuric acid resistant ordinary Portland cement caused severe sulfuric acid deterioration and aggregate exposure at -16%. On the other hand, the sulfuric acid resistance (mass change rate) of the cured product obtained by centrifugally molding the acid resistant concrete of the present embodiment was -0.8%, which was in a substantially healthy state.
That is, by compacting by centrifugal molding and manufacturing, it becomes possible to manufacture a sewer pipe having sulfuric acid resistance and high durability, and it is possible to reduce the labor of repair.
In addition, the acid-resistant concrete of the present embodiment can be subjected to centrifugal molding so that the steam curing time (pre-positioning time) can be shortened as compared with vibration molding, and it is possible to manufacture a product of precast concrete in a practical time. Become. Specifically, it is possible to manufacture a fume tube having excellent sulfuric acid resistance, which has a compressive strength of 40 N/mm ² or more after 28 days of age.

Further, in recent years, measures against global warming have been recognized as a common problem on a global scale, and the seriousness thereof is increasing every moment. For this reason, each country has already begun full-scale efforts to reduce greenhouse gases such as CO ₂ . Since cement is used for the fume pipe, CO ₂ emission is large at the time of cement production.
On the other hand, the acid-resistant concrete of the present embodiment can provide an ecological product that effectively utilizes industrial byproducts without using Portland cement at all.
This makes it possible to consider the global environment and contribute to the reduction of CO ₂ emissions.

The acid-resistant concrete according to the present embodiment can be used not only for fume pipes but also for precast concrete produced by centrifugal molding.
For example, the acid-resistant concrete according to the present embodiment is not only resistant to sulfuric acid, but also resistant to other acids such as hydrochloric acid resistance, so it can be used in power plants, factories, various production manufacturing facilities, etc. Is possible.

Further, as the industrial by-product of the present embodiment, it is possible to use other than fly ash, blast furnace slag fine powder, sewer sludge incineration ash, and silica fume. For example, it is also possible to use incineration ash of a biomass power plant, soot dust, residues of mineral refining, etc., containing Ca, Si, various inorganic metals, and the like.
In addition to slaked lime, alkali metal hydroxides such as sodium hydroxide, alkali metal hydrates, gypsum and the like can be used as the alkali stimulant.

<Second embodiment>
In the above-described first embodiment, Ca(OH) ₂ (calcium hydroxide, slaked lime) is used in a standard composition of 20 kg/m ³ , and the content range is 50 to 200% by weight (10 to 10%). An example of blending at 40 kg/m ³ ) has been described.
On the other hand, the acid-resistant concrete according to the second embodiment of the present invention contains more slaked lime than the above-described first embodiment. In the present embodiment, slaked lime is preferably blended at a rate of 50 to 500% (10 to 100 kg/m ³ ).
When the content of calcium hydroxide increases, the neutralization depth of the hardened material becomes significantly smaller. That is, if the amount of calcium hydroxide added is increased, a neutralization suppressing effect can be obtained. This effect will be shown as a result of a neutralization suppression effect test by the simple accelerated neutralization test apparatus of Example 2 described later.

Furthermore, the acid-resistant concrete of the present embodiment can be used as vibration-formed precast concrete, in addition to the centrifugal molding described above.
Examples of vibration molded products include box culverts and manholes. Any product can be manufactured by the same manufacturing method as the manufacturing process of precast concrete such as fume pipe. That is, it is possible to manufacture by simply changing centrifugal molding to vibration molding. Therefore, the mixture of the present embodiment can be applied to the production of vibration-formed precast concrete products.

At this time, the acid-resistant concrete of the present embodiment may have different performance requirements for the softness of the mixture depending on the product to which it is applied. In this case, the ratio (W/P) between the water (W) and the total amount of powder (P) in the mixture is adjusted so as to correspond to the ratio (W/C) between water (W) and cement (C) in concrete. It can be handled by just fine-tuning.
A product to which the fresh property of the mixture (slump: SL or air amount: Air) is applied by appropriately adjusting the fine aggregate ratio (S/a), the amount of admixture (Ad) added, etc., if necessary. It is possible to meet the required performance of.
As a formulation example when the mixture of the present embodiment is applied to an actual product, it is preferable to use the formulation as shown in Table 8 of Example 2 described later. Table 8 shows a compounding example when the mixture of the present embodiment is applied to a centrifugally molded product (fume tube) and when it is applied to a vibration molded product (box culvert).
In addition, as shown in Table 8, if a proper curing method and temperature control are sufficiently performed, it is also possible to use the mixture of the present embodiment and perform the casting on site.

Next, the present invention will be further described by way of examples based on the drawings, but the following specific examples do not limit the present invention.

[Acid resistance in standard formulation]
(Overview)
A mixture for producing the acid-resistant concrete of the present example (hereinafter, simply referred to as "the present mixture") was used as an experiment target of the present example. With the cured product (hereinafter simply referred to as "cured product") produced by centrifugal molding and vibration molding using this mixture, a test product was prepared in which the steam curing condition was set to 5 levels, and its strength development property was obtained. It was confirmed. Regarding the setting time of this mixture, a mortar setting test by a Proctor penetration resistance test was performed to confirm the starting time and the ending time. As for chemical resistance, a mortar cured product obtained by vibration-molding this mixture or a round-shaped test piece (specimen) collected from a centrifugally-molded cured product was immersed in a 5% strength sulfuric acid aqueous solution to obtain sulfuric acid resistance. It was compared with a test piece (specimen) made of ordinary Portland cement (hereinafter referred to as "OPC").

(Material used)
The types and qualities of the materials used in this example are as shown in Table 1 below. Materials used are four types of industrial by-products consisting of fly ash, blast furnace slag fine powder, super ash, and silica fume, calcium hydroxide (slaked lime) corresponding to JIS R9001 special issue as an alkali stimulant, and to prevent shrinkage cracks. There are six types of expansive materials that correspond to JIS A6202. Aggregates (coarse aggregates, fine aggregates), water, and a high-performance water reducing agent were kneaded with this to form this mixture.

(Formulation of this mixture)
The fresh property of this mixture was a high flow type with a slump flow of 650±50 mm as shown in FIG. It is assumed that this makes a marked difference from vibration molding.
The air content of this mixture was set to 2.0±1.5% as the target value from the measured value of the air content obtained at the time of freshness as a result of repeated test kneading.
As shown in Table 2 below, the mixture of the present mixture was such that the water powder ratio (W/P) was 34.0% and the fine aggregate ratio was 41.0%. The super ash was used by replacing the amount corresponding to 5% of the total powder amount with fine aggregate.

(Curing body molding method)
After kneading this mixture, a cured product was produced by vibration molding and centrifugal molding.
In vibration molding, a tin mold (φ100 x 200 mm) was filled with the fresh mixture in two layers, and while vibrating with a table vibrator, the mixture was compacted into two layers, and the column was cured. The body was made.
In centrifugal molding, a mold for centrifugal molding (φ200 x 300 mm) is filled with the fresh mixture, the mold is rotated at high speed on a molding machine, and it is compacted at an acceleration close to 40 G using centrifugal force. The excess water of the mixture was discharged as sludge water. At this time, the acceleration and the molding time shown in Table 3 below were used to increase the acceleration in several stages to compact the centrifugally hardened body.

2(a) and 2(b) show appearance properties of the manufactured centrifugally cured product. FIG. 2C shows the state of centrifugal molding.
In the centrifugal molding, the excess water of this mixture was smoothly discharged as sludge water by the acceleration G. As a result, the thickness of the fragile layer on the inner surface of the centrifugally hardened body was 0 mm, and good compaction properties were obtained. Further, the outer surface of the cured body became a very dense cured body due to centrifugal force.

(Setting time)
The curing reaction of this mixture was assumed to take a setting time in the natural state. Therefore, as a coagulation test, a starter time and a termination time were confirmed by a Proctor penetration resistance test. The mortar of the mixture used in this setting test is simply the composition of this mixture shown in Table 2 with the coarse aggregate removed.
As shown in FIG. 3, the setting time of this mixture was about 14 hours at the start and about 19 hours at the end. This is probably due to the pozzolanic reaction and latent hydraulic properties.

(Steam curing condition)
Based on the results of the setting test, in order to understand the steam curing conditions (preliminary time) effective for the strength development of the cured product, the effect of the pretreatment in steam curing on the strength development of this mixture was confirmed. In this example, the pre-treatment time, which is the time from the pouring of water to the start of the temperature rise, was 4 hours, the rising temperature was 20° C./h, the maximum temperature was 65° C., the holding time was 4 hours, and the cooling was a natural cooling. It went on condition. At this time, the pretreatment time was divided into 5 levels shown in Table 4 below. That is, the pretreatment time was 0.5 hours (30 minutes), 1.5 hours, 3.0 hours, 6.0 hours, and 24.0 hours, and the other steam curing conditions were the same.

(Compressive strength)
In Table 5 below, the test results of the compressive strength of the cured product are classified by vibration molding and centrifugal molding and are shown for each pre-positioning time and age.

FIG. 4 shows the results of vibration molding, and FIG. 5 shows the results of centrifugal molding as a graph. In each graph, the horizontal axis represents the pre-positioning time, and the vertical axis represents the compressive strength (N/mm ² ). In addition, δ of each bar indicates age (day). This clarified the difference between vibration molding and centrifugal molding.
Looking at the influence of the pre-treatment time, the pre-compression time of 0.5 hours has a low compressive strength in the initial age until the age of 14 days, and is particularly remarkable in the case of vibration molding for 1 day of age. A similar tendency is observed in the case of 1.5 hours for pre-treatment and 3.0 hours for pre-treatment, and the difference between them is slight, and the compressive strength fluctuates after 1 day of vibration molding.
On the other hand, when the pre-positioning time was 6.0 hours, the compressive strength generally remained firm as compared with the pre-positioning time shorter than this, and the centrifugal molding was 40 N/mm ² at the age of 28 days. The above compressive strength is obtained. Further, when the pre-positioning time was 24.0 hours, the compression strength reached the highest level. Based on the results of the above-mentioned setting test, it was speculated that this was an effect of ensuring a sufficient pre-positioning time, which was longer than the initial starting time of 14 hours for this mixture.
As described above, centrifugal molding was less affected by pretreatment time than vibration molding, and the compressive strength was generally higher than that of vibration molding by about 5 N/mm ² .

Next, in FIG. 6, based on the above results, the strength ratio of vibration molding to centrifugal molding (100%) is compared under each condition.
Looking at this strength ratio, in vibration molding, the compressive strength of the cured body reacts sharply during the pre-positioning time, and when the pre-positioning time is short such as 0.5 hours, 1.5 hours, and 3.0 hours. The strength ratio was about 85%. On the other hand, when the pre-treatment time was 6.0 hours or more, the strength ratio up to 14 days old exceeded 90%, and the difference from the centrifugal molding was small up to this stage.
According to these results, centrifugal molding was able to shorten the pre-positioning time of the present mixture as compared with vibration molding. Further, the compression strength of the cured product became higher than that of vibration molding.

(Sulfuric acid resistance)
(Sulfuric acid resistance of the cured product by vibration molding)
As a comparison target of the sulfuric acid resistance test, a mortar specimen (φ50×100 mm) by OPC was vibration-molded.
This mortar is obtained by simply removing the coarse aggregate from the concrete composition shown in Table 6 below.

Further, similarly to the above-mentioned setting test, a hardened body (φ50×100 mm) was produced by vibration molding using a mortar mixture obtained by simply removing the coarse aggregate from the mixture of the present mixture shown in Table 2.

These OPC-made cured products and the cured product of this mixture were immersed in a 5% strength sulfuric acid aqueous solution for 28 days in accordance with the "Quality test method for cross-section restoration mortar of the Japan Sewer Works" to change the mass. Sulfuric acid resistance was evaluated from the external appearance properties.
The amount (volume) of a 5% concentration sulfuric acid aqueous solution was 1.96 L per one test piece, and the surface area of the sample and the volume ratio of the liquid (solid solution ratio) were kept constant and a new sulfuric acid aqueous solution was prepared every 7 days. Replaced all.

FIG. 7 shows the appearance of each test piece after the 28-day immersion. FIG. 7(a) is an OPC test piece, and FIG. 7(b) is a test piece of a cured product of the present mixture.
The test results are shown in FIG. According to this, the mass of the OPC test piece decreased as the number of immersion days progressed, and the mass change rate reached -32% in 28 days.
On the other hand, the cured product of the present mixture was in a substantially healthy state and showed excellent acid resistance, although slight cracks were slightly generated.
However, the mass change rate after immersion for 28 days turned to the plus side of about 1%, and slight expansion was confirmed in the cured body. With respect to this result, the minerals that influence the expansion and mass increase of the cured product were identified by the X-ray diffraction method for the cured product of this mixture. As a result, it was estimated that the main cause was gypsum dihydrate (CaSO ₄ .2H ₂ O) produced from blast furnace slag fine powder.

(Sulfuric acid resistance of the cured product by centrifugal molding)
As described above, centrifugal molding was found to be effective in the results of the compressive strength test of the cured product made of this mixture.
Based on this, a round sliced test piece was sampled from a centrifugal test sample made of OPC having the composition shown in Table 6 above and a cured product obtained by centrifugally molding this mixture, and the sulfuric acid resistance was evaluated.
In this sulfuric acid immersion test, the collected test piece was immersed in a 5% strength sulfuric acid aqueous solution for 28 days without considering the surface area of the test piece and the volume ratio (solution ratio) of the solution.

FIG. 9 shows the appearance of each test piece after the 28-day immersion. FIG. 9(a) is a centrifuge specimen made of OPC, and FIG. 9(b) is a centrifuge specimen of this mixture.
The test results are shown in FIG. According to this, in the OPC centrifugal test piece (centrifugal OPC), a mass reduction of -16% and an exposure of the aggregate were confirmed in 28 days of immersion, and severe sulfuric acid deterioration occurred.
On the other hand, in the centrifuge specimen (centrifugal cured body) made of this mixture, although a mass reduction of −0.8% was observed in 28 days of immersion, almost no change was observed in the appearance properties of the test piece, which was sound. It was in a state.
Further, no fine cracks or slight expansion occurred in the mortar hardened body produced by vibration molding, demonstrating the effectiveness of compacting the hardened body by centrifugal molding.

(Summary)
In this example, Portland cement was not used at all to create a durable concrete product, which was cured by centrifugal molding using a mixture containing industrial by-products composed mainly of fly ash and blast furnace slag fine powder. I made it a body.
In this example, the following results were obtained:
(1) The curing reaction of this mixture was due to the pozzolanic reaction and latent hydraulicity, and the setting time was 14 hours at the beginning and 19 hours at the termination.
(2) In the case of vibration molding, strength development and strength elongation are poor. For example, the compressive strength after 6 hours of pre-treatment and 28 days of age was 35.1 N/mm ² . On the other hand, centrifugal molding has good strength development and strength elongation. For example, the compressive strength for 6 hours in the front and 28 days after the age is 40.7 N/mm ² .
(3) Due to the delay of the setting time, in the vibration forming, the compression strength is lower than that of 6.0 hours or more when the pre-treatment time of steam curing is 3.0 hours or less. However, in the case of centrifugal molding, the difference in compressive strength is smaller than that in the case of vibration molding when comparing 3.0 hours or less before pre-positioning time and 6.0 hours or more.
Therefore, by using the centrifugal molding, the delay of the setting time of the present mixture can be offset, and it can be used in the production of a practical fume tube. Specifically, it can be used for 1.5 hours or less.
(4) As a result of a 5% sulfuric acid immersion test targeting a mortar cured product by vibration molding and an OPC mortar sample, the OPC mortar sample had a mass change rate of -32%, whereas the mortar cured product. The body was in a nearly healthy state although slight swelling was observed.
(5) As a result of a 5% sulfuric acid immersion test targeting a centrifugally hardened body produced by centrifugal molding and a centrifugal test piece made of OPC, the mass reduction of the centrifugal test piece made of OPC was -16%. In the case of the centrifugally hardened body, the mass reduction was only -0.8%, and the appearance was in a generally sound state.

[Strength when the proportion of the mixture is changed]
The relationship between the addition rate of each material and the compressive strength was examined for the above-mentioned standard formulation. That is, a test was conducted on the change in compressive strength when the compounding ratio of each material was changed. The results are shown in Table 7 below.

Further, FIG. 11 shows a relationship graph between the addition rate and the strength. In each graph, the horizontal axis represents the ratio (%) of the addition ratio in weight percent with respect to the standard ratio. The vertical axis represents the compressive strength (N/mm ² ).
As a result, W (water) 90-105%, FA (fly ash) 10-110%, BFS (blast furnace slag fine powder) 90-190%, SF (silica fume) 50 in weight percent with respect to the standard formulation. ~130%, Ca(OH) ₂ (calcium hydroxide, slaked lime) 50-200%, EX (expandable material) 60-130%, S (fine aggregate) 80-125%, G (coarse aggregate) 80- It was suitable to mix it in the ratio of 125% and Ad (high performance water reducing agent) 50 to 150%. These effects are as described in the above embodiment.

(Sulfuric acid immersion test: Comparison of centrifugally cured product, OPC, BB, FC)
In Example 1, a centrifugal hardened body and a normal cement (OPC) centrifugal specimen were described. In addition to this, a sulfuric acid immersion test using a standard blast furnace cement type B (BB) centrifuge specimen and a standard fly ash cement type C (FC) centrifuge specimen was performed in the same manner as in Example 1. It was
FIG. 12 shows the appearance of deterioration status of various centrifugal specimens. FIG. 12(a) is a photograph of a blast furnace cement type B (BB) centrifuge specimen after immersion for 28 days, and FIG. 12(b) is a fly ash cement type C (FC) centrifuge specimen after immersion for 28 days. Is a photo of. In each case, the appearance was severely deteriorated.
FIG. 13 shows a graph in which various types of centrifugal test specimens were immersed in a 5% aqueous solution of sulfuric acid for 28 days, and the degree of deterioration was represented by a mass change rate.
As a result, as a result of immersing the various centrifugal specimens in a 5% aqueous solution of sulfuric acid for 28 days, the mass change rates were about -16% for centrifugal OPC and centrifugal FC, and about -10% for centrifugal BB.
On the other hand, the mass change rate of the centrifugally cured products of Examples 1 and 2 was only -0.8%, and it is possible to confirm the excellent sulfuric acid resistance of the cured products of these Examples. did it.

(W/P and strength development depending on the mixing ratio of FA and BFS)
Next, it was manufactured by changing the mixing ratio of fly ash (FA), which is the main material of the cured product, and blast furnace slag fine powder (BFS) to 50% to 50% and 40% to 60% and using it as a mortar. The strength development (mortar strength) of the cured product (φ50×100 mm) (mortar cured product) was compared by changing the water powder ratio (W/P).
FIG. 14 shows a graph of strength when the mixing ratio of FA and BFS is 50%:50%.
FIG. 15 shows a graph of the relationship between W/P and strength in the result of FIG. In the figure, σ indicates the material age (days).
FIG. 16 shows a graph of strength when the mixing ratio of FA and BFS is 40%:60%.
FIG. 17 shows a graph of the relationship between W/P and mortar strength in the result of FIG. In the figure, σ indicates the material age (days).

As a result, when the mixing ratio of the hardened material fly ash (FA) and the blast furnace slag fine powder (BFS) was changed from 50% to 50% to 40% to 60%, the compressive strength (especially the initial strength up to 14 days old) was obtained. Has improved. It was also found that when the W/P was 28% or less, the compressive strength of 28 days old was about 50 N/mm ² or more.

(Compressive strength of cylindrical hardened body and centrifugal hardened body)
Regarding the compressive strength when changing the mixing ratio of fly ash (FA) and blast furnace slag fine powder (BFS), which are the main materials of the cured body, to 50% to 50% and 40% to 60%, Example 1 and Similarly, a cylindrical cured body (φ100×200 mm) and a centrifugally cured body (φ200×300 mm) were compared by changing the water powder ratio (W/P). The fresh properties of these cured products were an air content of 1.8% and a slump of 10.0 cm.

FIG. 18 shows a graph of the compressive strength when the mixing ratio of FA and BFS is 50%:50%.
FIG. 19 shows a graph of the compressive strength when the mixing ratio of FA and BFS is 40%:60%.
As a result, when the water-powder ratio (W/P) of the cured product became smaller, the compressive strength tended to increase accordingly, as in Example 1.
Further, since the centrifugal test piece manufactured by centrifugal molding had a higher compressive strength than the cylindrical test piece manufactured by vibration molding, there was a tendency similar to the result of Example 1.

(Effect of calcium hydroxide)
The compressive strength of the cured mortar (excluding coarse aggregate) was compared by changing the addition amount of calcium hydroxide (Ca(OH) ₂ ) which is the alkali stimulant (curing accelerator) of the cured body.
FIG. 20 shows a graph of the relationship between the added amount of calcium hydroxide (Ca(OH) ₂ ) and the compressive strength. Here, an experiment was conducted in which the addition ratio of calcium hydroxide was changed under the conditions of W/P of 30%, flare ash of 40%, and blast furnace slag fine powder of 60%.
From this result, when the expression of compressive strength is examined, the optimum amount of calcium hydroxide mixed is 20 kg/m ³ , below which the strength level is low, and even if more than that, no improvement in strength can be obtained. Do you get it.

In addition to this, the present inventors examined the neutralization suppressing effect as a viewpoint other than the strength of the addition amount of calcium hydroxide.
FIG. 21 shows an outline of a simple accelerated neutralization test device used for the neutralization suppression effect test. In this device, the cured product (test sample) is allowed to stand in a desiccator, the lid is closed, and carbon dioxide (concentration of 40% or more) is sent to promote neutralization of the cured product.
In the neutralization suppressing effect test of this example, a vibration-molded mortar cured body (cured body) containing 40% fly ash and 60% blast furnace slag was prepared, and after steam curing, it was cured in air (at a temperature of 20° C.). , Humidity 60%) for 28 days, and then the neutralization was evaluated.
Neutralization was determined by spraying phenolphthalein (1% ethanol solution) on the split surface of the cured product, and targeting the colorless part where the reddish purple color reaction does not occur, the depth from the surface of the cured product. Was measured at 10 mm intervals to obtain an average value, which was taken as the neutralization depth.

FIG. 22 shows a graph of experimental results of the relationship between the amount of calcium hydroxide and the neutralization depth in the neutralization suppression effect test.
FIG. 23 shows a photograph of the color reaction of the cured product which was subjected to air curing for 28 days after steam curing as a result of the neutralization suppressing effect test. FIG. 23(a) is a photograph of a cured product containing 20 kg/m ³ of calcium hydroxide. The neutralization depth was 7 mm. FIG. 23(b) is a photograph of the cured product to which 40 kg/m ³ of calcium hydroxide was added. The neutralization depth was 2 mm. FIG. 23(c) is a photograph of a cured product to which 60 kg/m ³ of calcium hydroxide was added. The neutralization depth was 0 mm.

As a result of the neutralization inhibitory effect test by this simple accelerated neutralization test apparatus, it was found that the neutralization depth of the hardened body was remarkably reduced as the mixing amount of calcium hydroxide was increased. That is, as a result, it was found that an effect of suppressing neutralization was obtained when the amount of calcium hydroxide (Ca(OH) ₂ ) added was increased. That, Ca (OH) 2 (calcium hydroxide, slaked lime) is 20 kg / m ³ was used in the standard formulation, the range of content for this is preferably set to 50~500% (10~100kg / m ³⁾ is there.

(Strength of the hardened cylinder sampled when manufacturing the actual product)
Next, the compression strength of the vibration-cured cylindrical hardened body of the mixture, which was taken during the production of the actual product, was measured. Specifically, in a concrete secondary product factory, when manufacturing an actual product (φ250×2000 mm) of a centrifugally hardened body, a mixture of the mixture is taken from an input port, and a columnar hardened body (φ100×200 mm) produced by vibration molding is manufactured. Was measured. The fresh properties of this cured product were an air content of 1.9% and a slump of 13.0 cm.
FIG. 24 shows the compressive strength of this vibration-molded cylindrical hardened body.
As a result, a compressive strength of 41.5 N/mm ² was obtained after 28 days of age. It is considered that a higher value can be obtained by increasing the slump of the vibration-molded cylindrical hardened body.

(Fume tube manufacturing method)
Next, as an example of precast concrete using the mixture of this example, a manufacturing method for manufacturing a fume tube by centrifugal molding will be described.
FIG. 25 shows the manufacturing process of the fume tube. In the production of fume pipes, a reinforcing bar basket formed by combining reinforcing bars is installed in the formwork. Next, while the mold is rotated on the molding machine, concrete mixed by a mixer is added, and compaction is performed by centrifugal force (low speed, medium speed, high speed). At this time, the inner surface of the fume tube is finished at the same time. Then, the mold is steam-cured, gradually cooled, and then demolded. After a curing period, the fume tube is inspected for appearance and dimensions before shipment.
In the present example, when a cured product is manufactured, the above-mentioned powder material is used instead of cement. Thus, when the hardened product is manufactured by centrifugal molding, it can be carried out in the same manner as the manufacturing process of the fume tube.
In the case of vibration molding, precast concrete can be similarly produced by performing vibration molding during the “centrifugal molding/internal surface finishing” step of FIG.

(External pressure test of the actual product of centrifugal hardened body)
As the actual products of the centrifugally cured product, those of φ250×2000 mm and φ300×2000 mm were manufactured.
FIG. 26 shows an actual product and a test situation of this centrifugally cured product. FIG. 26(a) is an external appearance of a centrifugally hardened actual product manufactured with φ300×2000 mm. FIG.26(b) is a photograph which shows the external pressure test condition of a centrifugally hardened actual product.

The external pressure test was carried out on φ250×2000 mm, and the actual product of the centrifugally hardened body of this example and the conventional fume tube were conducted in parallel.
FIG. 27 shows the external pressure test results of the centrifugally cured actual product (φ250×2000 mm) of this example.
FIG. 28 shows the external pressure test result (comparative example) of a conventional fume tube (φ250×2000 mm).
As a result of the external pressure test, as compared with the conventional fume tube, the actual product of the centrifugally hardened body of this example satisfied the crack standard load and the fracture standard load sufficiently. That is, it was confirmed that the material has good load resistance. Furthermore, since the deflection is rather large, it is considered that brittle fracture is unlikely to occur.

(Application to vibration molded products)
Next, the present inventors manufactured an actual precast concrete product by the above-described vibration molding, and examined the optimum mixing ratio of the vibration molded product. Examples of this target include box culverts and manholes.
Table 8 below shows a compounding example when the mixture of the present example is applied to a centrifugally molded product (fume tube or the like) and to a vibration molded product (box culvert or the like). Further, as shown in the composition examples of Table 8 as the on-site construction, it is possible to pour the mixture on-site if a proper curing method and temperature control are sufficiently performed.

In Table 8, Gmax is the maximum size of the coarse aggregate, SL is the slump flow, Air is the air amount, W/P is the ratio of water (W) to the total powder amount (P), and S/a is the fine aggregate. %, S is fine aggregate, G is coarse aggregate, and Ad is an admixture.
Here, in any case, the acid resistance can be enhanced while satisfying the quality such as the standard load equal to or higher than that of the product using the conventional cement.

It is needless to say that the configurations and operations of the above-described embodiments are examples, and can be appropriately modified and executed without departing from the spirit of the present invention.

The acid-resistant concrete of the present invention does not contain Portland cement, is mixed with water, an industrial by-product, an alkali stimulating material, an expanding material, a fine aggregate, a coarse aggregate, and a high-performance water reducing agent, and centrifuges. It is characterized by being compacted by force forming.
The acid resistant concrete of the present invention is characterized in that the industrial by-products include fly ash, blast furnace slag fine powder, and silica fume, and the alkali stimulant includes slaked lime.
Acid resistance concrete of the present invention, the water 170 kg / m ^3, the fly ash to 207kg / m ^3, the blast furnace slag to 207kg / m ^3, the silica fume to 30kg / m ^3, the slaked lime 20 kg / m ^3, wherein the expandable material ^{30kg / m 3, 639kg / m} 3 the fine aggregate, the coarse aggregate 959kg / m ^3, and 5.434kg / m ³ the superplasticizer as a standard formulation, In weight percent, the water is 90 to 105%, the fly ash is 10 to 110%, the blast furnace slag fine powder is 90 to 190%, the silica fume is 50 to 130%, the slaked lime is 50 to 200%, and the expansion is performed. 60 to 130% of the material, 80 to 125% of the fine aggregate, 80 to 125% of the coarse aggregate, and 50 to 150% of the high-performance water reducing agent.
Acid resistance concrete of the present invention, the water 170 kg / m ^3, the fly ash to 207kg / m ^3, the blast furnace slag to 207kg / m ^3, the silica fume to 30kg / m ^3, the slaked lime 20 kg / m ^3, wherein the expandable material ^{30kg / m 3, 639kg / m} 3 the fine aggregate, the coarse aggregate 959kg / m ^3, and 5.434kg / m ³ the superplasticizer as a standard formulation, In weight percent, the water is 90 to 105%, the fly ash is 10 to 110%, the blast furnace slag fine powder is 90 to 190%, the silica fume is 50 to 130%, the slaked lime is 50 to 500%, and the expansion is performed. 60 to 130% of the material, 80 to 125% of the fine aggregate, 80 to 125% of the coarse aggregate, and 50 to 150% of the high-performance water reducing agent.
The acid-resistant concrete of the present invention does not contain Portland cement, is mixed with water, an industrial by-product, an alkali stimulating material, an expanding material, a fine aggregate, a coarse aggregate, and a high-performance water reducing agent, and vibrates. Manufactured by molding, the industrial by-products include fly ash, blast furnace slag fine powder, and silica fume, the alkaline stimulant includes slaked lime, the water is 170 kg/m ³ , the fly ash is 207 kg/m ³ , the blast furnace slag to 207kg / m ^3, the silica fume to 30kg / m ^3, the slaked lime 20 kg / m ^3, the expanding material to 30kg / m ^3, the fine aggregate to 639kg / m ^3, the coarse aggregate as a 959kg / m ^3, and the high performance water reducing agent compounded 5.434kg / m ³ of standard, in weight percent, the water 90 to 105%, 10-110% of the fly ash, the blast furnace slag 90-190% powder, 50-130% silica fume, 50-500% slaked lime, 60-130% expansive material, 80-125% fine aggregate, 80-125 coarse aggregate. %, and the high-performance water reducing agent are blended at a ratio of 50 to 150%.
The acid-resistant concrete of the present invention is characterized in that, as the industrial by-product, 26 kg/m ³ of sewer sludge incineration ash is used as a standard composition, and the sewer sludge incineration ash is compounded in a weight ratio of up to 200%. ..
The acid-resistant concrete of the present invention is characterized in that it is steam-cured after molding, and the pre-treatment time of the steam curing is 1.5 hours or more.
The acid-resistant concrete of the present invention does not contain Portland cement, and is mixed with water, an industrial by-product, an alkali stimulating material, an expanding material, a fine aggregate, a coarse aggregate, and a high-performance water reducing agent. The industrial by-product includes fly ash, blast furnace slag fine powder, and silica fume, the alkaline stimulant includes slaked lime, the water is 170 kg/m ³ , and the fly ash is 207 kg/m ^3. the blast furnace slag to 207kg / m ^3, the silica fume to 30kg / m ^3, the slaked lime the 20 kg / m ^3, the expansion member 30kg / m ^3, the fine aggregate 639kg / m ^3, the coarse aggregate material to 959kg / m ^3, and 5.434kg / m ³ the superplasticizer as a standard formulation, in weight percent, the water 90 to 105%, from 10 to 110% of the fly ash, the blast furnace slag Fine powder 90-190%, silica fume 50-130%, slaked lime 50-500%, expander 60-130%, fine aggregate 80-125%, coarse aggregate 80- 125% and the high-performance water reducing agent are mixed in a ratio of 50 to 150%, and as the industrial by-product, a sewer sludge incineration ash of 26 kg/m ³ is used as a standard composition, and the sewer sludge incinerator ash is 200 in weight percent. It is characterized by blending in a ratio of up to %.
The precast concrete of the present invention is characterized by being produced from the acid resistant concrete.
The precast concrete of the present invention is characterized by being a sewer pipe.
The acid-resistant concrete production method of the present invention does not include Portland cement, water, an industrial by-product, an alkali stimulating material, an expansive material, a fine aggregate, a coarse aggregate, and a high-performance water reducing agent, It is characterized by compaction by centrifugal force molding, vibration molding, or placing by site construction.

Claims (11)

Water, an industrial by-product, an alkali stimulating material, an expanding material, a fine aggregate, a coarse aggregate, and a high-performance water reducing agent are blended,
Acid-resistant concrete that is manufactured by compaction by centrifugal force molding. The industrial by-products include fly ash, blast furnace slag fine powder, and silica fume,
The acid-resistant concrete according to claim 1, wherein the alkali stimulant contains slaked lime. The water is 170 kg/m ³ , the fly ash is 207 kg/m ³ , the blast furnace slag fine powder is 207 kg/m ³ , the silica fume is 30 kg/m ³ , the slaked lime is 20 kg/m ³ , and the expansive material is 30 kg/m ³ . m ³ , the fine aggregate is 639 kg/m ³ , the coarse aggregate is 959 kg/m ³ , and the high-performance water reducing agent is 5.434 kg/m ³ as a standard composition,
In weight percent, the water is 90 to 105%, the fly ash is 10 to 110%, the blast furnace slag fine powder is 90 to 190%, the silica fume is 50 to 130%, the slaked lime is 50 to 200%, and the expansion is performed. 60 to 130% of the material, 80 to 125% of the fine aggregate, 80 to 125% of the coarse aggregate, and 50 to 150% of the high-performance water reducing agent are mixed. Acid-resistant concrete according to 2. The water is 170 kg/m ³ , the fly ash is 207 kg/m ³ , the blast furnace slag fine powder is 207 kg/m ³ , the silica fume is 30 kg/m ³ , the slaked lime is 20 kg/m ³ , and the expansive material is 30 kg/m ³ . m ³ , the fine aggregate is 639 kg/m ³ , the coarse aggregate is 959 kg/m ³ , and the high-performance water reducing agent is 5.434 kg/m ³ as a standard composition,
In weight percent, the water is 90 to 105%, the fly ash is 10 to 110%, the blast furnace slag fine powder is 90 to 190%, the silica fume is 50 to 130%, the slaked lime is 50 to 500%, and the expansion is performed. 60 to 130% of the material, 80 to 125% of the fine aggregate, 80 to 125% of the coarse aggregate, and 50 to 150% of the high-performance water reducing agent are mixed. Acid-resistant concrete according to 2. Water, an industrial by-product, an alkali stimulating material, an expanding material, a fine aggregate, a coarse aggregate, and a high-performance water reducing agent are blended,
Manufactured by vibration molding,
The industrial by-products include fly ash, blast furnace slag fine powder, and silica fume,
The alkaline stimulant includes slaked lime,
The water is 170 kg/m ³ , the fly ash is 207 kg/m ³ , the blast furnace slag fine powder is 207 kg/m ³ , the silica fume is 30 kg/m ³ , the slaked lime is 20 kg/m ³ , and the expansive material is 30 kg/m ³ . m ³ , the fine aggregate is 639 kg/m ³ , the coarse aggregate is 959 kg/m ³ , and the high-performance water reducing agent is 5.434 kg/m ³ as a standard composition,
In weight percent, the water is 90 to 105%, the fly ash is 10 to 110%, the blast furnace slag fine powder is 90 to 190%, the silica fume is 50 to 130%, the slaked lime is 50 to 500%, and the expansion is performed. 60 to 130% of the material, 80 to 125% of the fine aggregate, 80 to 125% of the coarse aggregate, and 50 to 150% of the high-performance water reducing agent. concrete. As the industrial by-product,
The sewage sludge incineration ash 26 kg/m ³ is used as a standard mixture, and the sewage sludge incineration ash is mixed in a weight ratio of up to 200%. Acid resistant concrete. The acid-resistant concrete according to any one of claims 1 to 6, which is steam-cured after molding and has a precuring time of 1.5 hours or more. Water, an industrial by-product, an alkali stimulating material, an expanding material, a fine aggregate, a coarse aggregate, and a high-performance water reducing agent are blended,
Placed on-site construction,
The industrial by-products include fly ash, blast furnace slag fine powder, and silica fume,
The alkaline stimulant includes slaked lime,
The water is 170 kg/m ³ , the fly ash is 207 kg/m ³ , the blast furnace slag fine powder is 207 kg/m ³ , the silica fume is 30 kg/m ³ , the slaked lime is 20 kg/m ³ , and the expansive material is 30 kg/m ³ . m ³ , the fine aggregate is 639 kg/m ³ , the coarse aggregate is 959 kg/m ³ , and the high-performance water reducing agent is 5.434 kg/m ³ as a standard composition,
In weight percent, the water is 90 to 105%, the fly ash is 10 to 110%, the blast furnace slag fine powder is 90 to 190%, the silica fume is 50 to 130%, the slaked lime is 50 to 500%, and the expansion is performed. 60-130% of the material, 80-125% of the fine aggregate, 80-125% of the coarse aggregate, and 50-150% of the high-performance water reducing agent are mixed,
An acid-resistant concrete, characterized in that, as the industrial by-product, 26 kg/m ³ of sewage sludge incineration ash is used as a standard mixture, and the weight of the sewage sludge incineration ash is 200%. Precast concrete produced by the acid-resistant concrete according to any one of claims 1 to 7. The precast concrete according to claim 9, which is a sewer pipe. Mixing water, industrial by-products, alkali stimulating material, expanding material, fine aggregate, coarse aggregate, and high-performance water reducing agent,
A method for producing acid-resistant concrete, which comprises compacting by centrifugal force molding, vibration molding, or placing at the site.

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