JP6796743B2 - Acid-resistant concrete, precast concrete, and acid-resistant concrete manufacturing method - Google Patents

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 useful life of more than 50 years have been repaired and maintained and renewed. Further, even in a sewer pipe having a service life of less than 50 years, "sulfuric acid deterioration" in which the inside of the pipe is corroded by hydrogen sulfide is becoming serious. When this is severe, cases have been reported that caused road collapse accidents. For this reason, a highly durable sewer pipe having a service life of 100 years is required, and it is attracting attention as a need for a new era.

Here, according to Patent Document 1, it is a coated mortar that can protect concrete and mortar, and is excellent in plastering workability, pumping property, sagging resistance, adhesiveness, shape-dimensional stability, and crack resistance. Further, a corrosion-resistant mortar composition having excellent acid resistance is described. This corrosion resistant mortar composition is substantially free of cement polymers, (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 the mortar composition in a specific ratio, and further, (G) a water reducing agent, (H) an antifoaming agent, and (I). ) Includes one or more components selected from alkali metal carbonate or aterate, (J) alkali metal sulfate, and (K) one or more selected from organic fibers.

JP-A-2017-132667

Toshiaki Idenoshita, Masami Uzawa, Shin Yamaguchi, Masahiro Maeda, Hideki Ikawa, Seiji Hosaka, "Strength characteristics and microstructural changes of mortar mixed with sewage sludge incineration ash under various curing conditions, materials, Journal of Science 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 has been 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.

Acid resistance concrete of the present invention are free of Portland cement, water, and industrial by-products, an alkaline stimulating member, an expansion member, and fine aggregate, and coarse aggregate, and a high performance water reducing agent is blended, the Industrial by-products include fly ash, blast furnace slag fine powder, and silica fume, and the alkaline stimulant is characterized by containing 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, By weight percent, 90-105% of the water, 10-110% of the fly ash, 90-190% of the blast furnace slag fine powder, 50-130% of the silica fumes, 50-200% of the decalcified lime, said expansion. The material is 60 to 130%, the fine aggregate is 80 to 125%, the coarse aggregate is 80 to 125%, and the high-performance water reducing agent is 50 to 150%.
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, By weight percent, 90-105% of the water, 10-110% of the fly ash, 90-190% of the blast furnace slag fine powder, 50-130% of the silica fumes, 50-500% of the decalcified lime, said expansion. The material is 60 to 130%, the fine aggregate is 80 to 125%, the coarse aggregate is 80 to 125%, and the high-performance water reducing agent is 50 to 150%.
Acid resistance concrete of the present invention are free of Portland cement, water, and industrial by-products, an alkaline stimulating member, an expansion member, and fine aggregate, and coarse aggregate, and a high performance water reducing agent is blended, the Industrial by-products include fly ash, blast furnace slag fine powder, and silica fume, and the alkaline stimulant contains slaked lime, 170 kg / m ^{3 of the} water, 207 kg / m ^{3 of} the fly ash, and 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 5.434 kg / m ³ of the high-performance water reducing agent as a standard formulation, 90 to 105% of the water, 10 to 110% of the fly ash, and 90 to 190% of the blast furnace slag fine powder in weight percent. , 50-130% of the silica fumes, 50-500% of the fly ash, 60-130% of the slag, 80-125% of the fine aggregate, 80-125% of the coarse aggregate, and the high performance. It is characterized in that a water reducing agent is blended in a ratio of 50 to 150%.
The acid-resistant concrete of the present invention is characterized in that, as the industrial by-product, sewage sludge incineration ash 26 kg / m ³ is standardly blended, and the sewage sludge incineration ash is blended up to 200% by weight. ..
The precast concrete of the present invention is characterized by being manufactured from the acid resistant concrete.
The precast concrete of the present invention is characterized by being a sewer pipe.
The acid-resistant concrete manufacturing method of the present invention does not contain Portland cement and contains water, industrial by-products, an alkali stimulant, an expansion material, a fine aggregate, a coarse aggregate, and a high-performance water reducing agent. The industrial by-products include fly ash, blast furnace slag fine powder, and silica fume, and the alkaline stimulant contains slaked lime and is characterized by being compacted by centrifugal molding, vibration molded, or cast on site. And.
The acid-resistant concrete manufacturing method of the present invention does not contain Portland cement, and contains water, industrial by-products, an alkali stimulant, a slag material, a fine aggregate, a coarse aggregate, and a high-performance water reducing agent. , Manufactured by vibration molding, the industrial by-products include fly ash, blast furnace slag fine powder, and silica fume, the alkali stimulant contains slaked lime, 170 kg / m ^{3 of} water, 207 kg / m of fly ash. ^3, wherein the blast furnace slag to 207kg / m ^3, the silica fume to 30kg / m ^3, the slaked lime the 20 kg / m ^3, the expanding material to 30kg / m ^3, the fine aggregate to 639kg / m ^3, the coarse aggregate 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 90-190% of slag fine powder, 50-130% of silica fumes, 50-500% of fly ash, 60-130% of swelling material, 80-125% of fine aggregate, 80 of coarse aggregate It is characterized by blending ~ 125% and the high-performance water reducing agent in a ratio of 50 to 150%.
The acid-resistant concrete manufacturing method of the present invention is characterized by being steam-cured after molding and having a pre-curing time of 1.5 hours or more.
The acid-resistant concrete manufacturing method of the present invention does not contain Portland cement, and contains water, industrial by-products, an alkali stimulant, a slag material, a fine aggregate, a coarse aggregate, and a high-performance water reducing agent. , The industrial by-products cast on-site, containing fly ash, blast furnace slag fine powder, and silica fume, the alkaline stimulant containing slaked lime, 170 kg / m ^{3 of} water, 207 kg / m ³ of fly ash. m ³ , the blast furnace slag fine powder 207 kg / m ³ , the silica fume 30 kg / m ³ , the fly ash 20 kg / m ³ , the expansion material 30 kg / m ³ , the fine aggregate 639 kg / m ³ , the said the coarse aggregate 959kg / m ^3, and the high performance water reducing agent as blended 5.434kg / m ³ of the standard, 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%, fly ash 50-500%, expansion material 60-130%, fine aggregate 80-125%, coarse aggregate 80-125% and the high-performance water reducing agent are blended in a ratio of 50-150%, and as the industrial by-product, the sewer slag incineration ash 26 kg / m ³ is standardly blended, and the sewer slag incineration ash in weight percent Is blended in a ratio of up to 200%.

According to the present invention, water, an industrial by-product, an alkaline stimulant, an expansion material, a fine aggregate, a coarse aggregate, and a high-performance water reducing agent are blended and compacted by centrifugal molding. As a result, it is possible to provide acid-resistant concrete having a long service life without the need for coating or the like.

It is a photograph which shows the slump flow of this mixture which concerns on Example 1 of this invention. It is a photograph of the appearance and the centrifugal molding of the centrifugally cured body which concerns on Example 1 of this 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 vibrating hardened body which concerns on Example 1 of this invention. It is a graph which shows the change of the compressive strength of the centrifugally molded hardened body which concerns on Example 1 of this invention. It is a graph of the strength ratio of vibration molding with respect to centrifugal molding which concerns on Example 1 of this invention. It is a photograph after the sulfuric acid resistance test of the hardened body of the vibration molding which concerns on Example 1 of this invention. 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 photograph after the sulfuric acid resistance test of the centrifugally molded hardened body which concerns on Example 1 of this invention. 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 between the addition rate and the compressive strength about the standard compounding of this mixture which concerns on Example 1 of this invention. It is a photograph after the sulfuric acid resistance test which concerns on Example 2 of this 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 expression test which concerns on Example 2 of this invention. It is a graph which shows the result of the strength expression test which concerns on Example 2 of this invention. It is a graph which shows the result of the strength expression test which concerns on Example 2 of this invention. It is a graph which shows the result of the strength expression test which concerns on Example 2 of this invention. It is a graph which shows the result of the compressive strength test of the columnar cured product and the centrifugal cured body which concerns on Example 2 of this invention. It is a graph which shows the result of the compressive strength test of the columnar cured product and the centrifugal cured body which concerns on Example 2 of this invention. It is a graph which shows the result of the compression strength test by the addition amount of 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 which concerns on Example 2 of this invention. It is a graph which shows the result of the compressive strength test of the actual product of the vibrating molded cylindrical hardened body which concerns on Example 2 of this invention. It is a flow chart which shows the manufacturing process of the Hume 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 cured product 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 diligent experiments and developments aiming at a highly durable sewer pipe having excellent acid resistance such as sulfuric acid resistance and a service life of 100 years, and have 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 made into a cured product using centrifugal molding, and can be applied to concrete products that require 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 by-product, an alkaline stimulant, an expansion material, a fine aggregate, a coarse aggregate, and a high-performance water reducing agent, and is compacted by centrifugal molding. It is characterized in that it is manufactured.

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 of water according to this embodiment is also arbitrary.

In addition, the industrial by-products of acid-resistant concrete of the present embodiment are characterized by containing fly ash, blast furnace slag fine powder, and silica fume.

The fly ash according to the present embodiment is a polaron coal ash (fly ash) for concrete collected by a dust collector for pulverized coal combustion 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 specified in JIS A 6201, having a density of about 2.20 g / cm ³ is preferable. Since fly ash is mainly composed of silica and alumina, it is cured by a pozzolan reaction that produces calcium silicate hydrate and the like with an alkaline stimulant.

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. As the blast furnace slag fine powder, for example, a blast furnace slag fine powder having a specific surface area of 4000 powder as specified in JIS A 6206 is suitable. Further, it is preferable that the density is about 2.91 g / cmg / cm ³ . Blast furnace slag fine powder is also cured by "latent hydraulic", which cures by producing calcium silicate hydrate and calcium aluminate hydrate with an alkaline stimulant.

Further, 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 this silica fume having a density of about 2.30 g / cm ³ specified in JIS A 6207. Silica fume is preferably used for densification and strength improvement of the cured product after centrifugation.

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

Further, the acid-resistant concrete of the present embodiment preferably contains slaked lime as an alkali stimulant. For this 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 alkaline stimulant makes it possible to cure fly ash and blast furnace slag fine powder without using any conventional Portland cement.

Further, the expanding material according to the present embodiment is a substance in the form of powder, which expands by supplying water and has a property of reducing cracks due to drying shrinkage. Examples of the expanding material of the present embodiment include a lime-based expanding material, an ettringite-based (calcium sulfate-based) expanding material, and an ettringite-quicklime composite-based expanding material. Of these, in the present embodiment, it is preferable to use a lime-based expanding material as the expanding material. Further, the expansion material is preferably one that conforms to the quality specified in, for example, Japanese Industrial Standard JIS A 6202.

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

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

In addition, the high-performance water reducing agent 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, for example, JIS A 6204, and it is preferable to use, for example, a polycarboxylic acid-based agent having a density of about 1.00 g / cm ³ .

Also, acid resistance concrete of this embodiment, water 170 kg / m ^3, fly ash 207kg / m ^3, blast furnace slag 207kg / m ^3, silica fume 30kg / m ^3, slaked lime 20 kg / m ^3, expansive 30kg / m ^3, fine aggregate 639kg / m ^3, characterized by a coarse aggregate 959kg / m ^3, and superplasticizer 5.434kg / m ³ standard formulation.

Of these, 90 to 105% of water is preferably blended, with the standard blending being 100% by weight. That is, it is preferable to blend water ^{150kg / m 3 ~175kg / m 3} . With this formulation, sludge water discharge is good. If 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, sludge water increases and the strength decreases.

Similarly, fly ash is preferably blended in a proportion of 10-110%. Of these, although the strength gradually increases as the blending amount decreases, the amount of blast furnace slag fine powder used increases, so it is preferable to set the lower limit to about 10%. Further, if 110% or more is blended, the strength is lowered, which is not preferable.
Further, the blast furnace slag fine powder is preferably blended in a ratio of 90 to 190%. Here, if the blending amount is reduced, the amount of fly ash increases and the strength decreases. Therefore, it is preferable to set the lower limit to about 90%. On the contrary, although the strength gradually increases as the amount used increases, the amount of fly ash decreases, so it is preferable to limit the blending to about 190%.
Further, it is preferable to blend Super Ash in a ratio of 0 to 200%. That is, it may be 0% that is not used, and if the mixing ratio is reduced, the strength of the cured product is improved. On the contrary, if it is blended in an amount of more than 200%, the strength of the cured product is significantly reduced, which is not preferable.
Further, the silica fume is preferably blended in a ratio of 50 to 130%. With this formulation, it is possible to realize densification and strength improvement of the cured product after centrifugation. If it is less than 50%, the fragile layer on the inner surface disappears, but densification and strength improvement cannot be realized. On the other hand, if more than 130% is blended, the fragile layer on the inner surface of the cured product increases, the performance as a sewer pipe deteriorates, and the strength does not improve.
That is, as the mixing ratio of the industrial by-products of the present embodiment, silica fume is blended with fly ash and blast furnace slag fine powder as main components. In addition, Super Ash may or may not be blended.

Further, slaked lime is preferably blended in a ratio of 50 to 200%. If the composition is less than 50%, the strength is lowered, which is not preferable. Even if more than 200% is blended, the strength is not improved. 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 expansion material is preferably blended at a ratio of 60 to 130%. If it is less than 60%, the shrinkage crack prevention effect becomes insufficient. Even if it is more than 130%, the shrinkage crack prevention effect is not improved.
Further, it is preferable to blend the fine aggregate in a ratio of 80 to 125%. If it is less than 80%, the surface of the cured product becomes rough and the strength decreases because there is little fine aggregate and the amount of coarse aggregate is excessive, which is not preferable. If it is more than 125%, fine aggregate and water increase, and the strength decreases, which is not preferable.
Further, the coarse aggregate is preferably blended at a ratio of 80 to 125%. If it is less than 80%, fine aggregate and water increase and the strength decreases, which is not preferable. If it is more than 125%, the coarse aggregate is excessive and the fine aggregate is small, the surface of the cured product becomes rough, and the strength is lowered, which is not preferable.
Further, the high-performance water reducing agent is preferably blended at a ratio of 50 to 150%. If it is less than 50%, water increases and the strength of the product decreases, which is not preferable. If it is more than 150%, it is over-added, the fluidity becomes excessive, the setting delay occurs, the strength decreases, and the cost increases, which is not preferable. Further, in the present embodiment, it is preferable to use the high-performance water reducing agent as a replacement for the internal division of water.

Further, the acid-resistant concrete according to the present embodiment is preferably compacted by centrifugal molding. In this centrifugal molding, a mixture of water, an industrial by-product, an alkaline stimulant, a swelling material, a fine aggregate, a coarse aggregate, and a high-performance water reducing agent mixed in the above ratio (hereinafter, simply referred to as "mixture"). Is filled in a mold for centrifugation, the mold is rotated at high speed on a molding machine, and finally compacted at an acceleration of about 30 to 50 G using centrifugal force, and excess water is discharged as sludge water. At this time, the acceleration may be increased in several steps to compact the surplus water so that the excess water is appropriately drained and compacted. In this stage, for example, 5G, 15G, and 35G are compacted at a ratio of 1 minute, 1 minute, and 7 minutes, respectively. By manufacturing by centrifugal molding compaction in this way, the acid-resistant concrete according to the present embodiment enhances not only strength but also 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 steam-cured after molding, and the pre-curing time of the steam-curing is 1.5 hours or more. Precast concrete may be steam cured in order to shorten the time to demolding and increase production efficiency. In this case, it is preferable to adjust the steam curing conditions such as the pre-preparation time, the rising temperature (heating), the maximum temperature, the holding time, and the cooling method according to the target product and the compounding conditions. Of these, the preposition time is the time from water injection to the start of temperature rise.
In the present embodiment, for example, the preposition time is maintained at 1.5 to 4 hours, the temperature rise is maintained at 15 to 25 ° C./hour, 60 to 75 ° C. for 3 to 5 hours or more, and then gradually at the test room temperature. Use conditions such as cooling and curing in the air. By steam curing under such conditions, the condensation and curing (strength development) 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 preposition time is particularly large. As explained below, by performing centrifugal molding, if the pre-preparation time is 1.5 hours or more, even if it is less than 6 hours, it is possible to produce concrete with sufficient strength and excellent acid resistance. It will be possible.

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

The amount of air in the acid-resistant concrete according to this embodiment is preferably 2.0 ± 1.5%, that is, 0.5 to 3.5%. As a result, the desired strength can be obtained while improving the 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. In addition, examples of this anionic surfactant include resin-based surfactants, alkylbenzene sulfonic acid-based surfactants, higher alcohol ester-based surfactants, and the like. In the present embodiment, it is particularly preferable to use a modified rosinic acid compound-based anionic surfactant. It is also possible to use an AE water reducing agent having the properties of both 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 such fibers include fibrous substances such as vinylon fibers, acrylic fibers, and carbon fibers. In addition, zeolite, silica fine powder, calcium carbonate, clay minerals such as bentonite, gypsum, calcium silicate and the like may be appropriately blended.

In addition, in the acid-resistant concrete according to the present embodiment, in addition, a fluidizing agent, a retarding agent, a waterproof admixture, a moisture-proof admixture, a foaming agent, a thickener, an antifreeze agent, a coloring agent, a workability enhancer, and an anti-protection agent It is possible to appropriately add a syrup, an antifreeze agent, a coagulation adjuster, 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 producing precast concrete. The precast concrete is preferably a Hume pipe. Further, as a use of this Hume pipe, it can be used as a highly durable sewer pipe.
With the above-described configuration, the acid-resistant concrete according to the present embodiment can exhibit sufficient acid-resistant capacity. In addition, it is possible to improve the manufacturing efficiency when manufacturing concrete products in a dedicated factory. Therefore, it is possible to suitably manufacture a sewer pipe with the acid-resistant concrete according to the present embodiment.
In addition, conventional sewer pipes include hume pipes, ceramic pipes, vinyl chloride pipes, etc., and each sewer pipe has a set purpose of use. On the other hand, since the precast concrete according to the present embodiment has high durability, it can be used in places where it is necessary to use a ceramic pipe or the like.

With the above configuration, the following effects can be obtained.
Conventional sewer pipes are mainly reinforced concrete pipes called Hume pipes. Such reinforced concrete and mortar are composed of water, cement and aggregate, and are hardened by a hydration reaction. Therefore, when it is used for a sewer pipe, "sulfuric acid deterioration" in which the inside of the pipe is corroded by hydrogen sulfide is serious, and it takes time and effort to repair it. The service life of Hume pipes is about 50 years, and in recent years, the sewer pipes that have spread rapidly have been maintained and renewed during the high growth period of the Showa era. Even when the useful life of the Hume pipe is less than 50 years, the sewer pipe is corroded and deteriorated (sulfuric acid deterioration) by hydrogen sulfide generated in the pipe, and in some cases, the road collapses when this is severe.
However, it is costly to apply the mortar described in Patent Document 1 or the sulfuric acid-resistant ordinary Portland cement to this maintenance. For this reason, acid-resistant concrete, which is a hardened body with high acid resistance, has been required in the first place.
On the other hand, the acid-resistant concrete of the present embodiment mainly uses a mixture containing an alkaline stimulant and an industrial by-product containing fly ash and blast furnace slag fine powder, so that conventional sulfuric acid-resistant ordinary Portland cement is used. Chemical resistance is improved and acid resistance can be increased.
Specifically, as shown in Example 1 described later, in a sulfuric acid resistance test in which the sample is immersed in a sulfuric acid aqueous solution having a concentration of 5% for 28 days, the sulfuric acid resistance (mass) of a test piece obtained by vibration-molding ordinary Portland cement. The rate of change) was −32%, and severe sulfuric acid deterioration occurred. On the other hand, in the test piece obtained by vibrating the acid-resistant concrete of the present embodiment, the hardened body was in a generally 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 unlike vibration molding does not occur, and the durability can be further improved.
As an effect of this centrifugation, as shown in Example 1 described later, the cured product obtained by centrifuging the sulfuric acid-resistant ordinary Portland cement had 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 a generally healthy state.
That is, by compacting and manufacturing by centrifugal molding, 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.
Further, the acid-resistant concrete of the present embodiment can be shortened in steam curing time (pre-preparation time) as compared with vibration molding by performing centrifugal molding, and it is possible to manufacture a precast concrete product in a practical time. Become. Specifically, it is possible to manufacture a Hume pipe having excellent sulfuric acid resistance, which has a compressive strength of 40 N / mm ² or more at a material age of 28 days.

In recent years, global warming countermeasures have come to be recognized as a common issue on a global scale, and their seriousness 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 Hume pipes, it emits a large amount of CO ₂ during cement production.
On the other hand, the acid-resistant concrete of the present embodiment does not use Portland cement at all, and can provide an ecological product that effectively utilizes industrial by-products.
As a result, it is possible to consider the global environment and contribute to the reduction of CO ₂ emissions.

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

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

<Second embodiment>
In the first embodiment described above, Ca (OH) ₂ (calcium hydroxide, slaked lime) is used in a standard formulation 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 ) was 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-mentioned first embodiment. In the present embodiment, the slaked lime is preferably blended at a ratio of 50 to 500% (10 to 100 kg / m ³ ).
As the amount of calcium hydroxide mixed in increases, the neutralization depth of the cured product becomes significantly smaller. That is, when the amount of calcium hydroxide added is increased, the effect of suppressing neutralization can be obtained. This effect is shown as the result of the neutralization suppression effect test by the simple accelerated neutralization test apparatus of Example 2 described later.

Further, the acid-resistant concrete of the present embodiment can be used as a vibration-formed precast concrete in addition to the above-mentioned centrifugal molding.
Examples of vibration-molded products include box culverts and manholes. Both products can be manufactured by the same manufacturing method as the manufacturing process of precast concrete such as Hume pipe. That is, it can be manufactured only by changing the centrifugal molding to the vibration molding. Therefore, the mixture of the present embodiment can also be applied to the production of vibration-forming precast concrete products.

At this time, the acid-resistant concrete of the present embodiment may have different required performance for the softness of the mixture depending on the product to which it is applied. In this case, the ratio (W / P) of the mixture water (W) and the total powder amount (P) is set so as to correspond to the ratio (W / C) of water (W) and cement (C) in concrete. It can be handled by just making fine adjustments.
In addition, a product to which the fresh properties of the mixture (slump: SL and air amount: Air) are applied by appropriately adjusting the fine aggregate ratio (S / a) and the amount of admixture (Ad) added as necessary. It is possible to match the required performance of.
As a formulation example when the mixture of this embodiment is applied to an actual product, it is preferable to use a formulation as shown in Table 8 of Example 2 described later. Table 8 shows compounding examples when the mixture of the present embodiment is applied to a centrifugal molded product (Hume pipe) and a vibration molded product (box culvert).
As shown in Table 8, if an appropriate curing method and temperature control are sufficiently performed, the mixture of the present embodiment can be used for casting on site.

Next, the present invention will be further described with reference to the drawings, but the following specific examples do not limit the present invention.

[Acid resistance in standard formulation]
(Overview)
A mixture for producing acid-resistant concrete of this example (hereinafter, simply referred to as "this mixture") was used as an experimental target of this example. In a cured product (hereinafter, simply referred to as "cured product") produced by centrifugation and vibration molding using this mixture, a specimen in which steam curing conditions are set to 5 levels is produced, and its strength development is exhibited. It was confirmed. Regarding the setting time of this mixture, a mortar setting test was conducted by a Proctor penetration resistance test to confirm the starting time and ending time. Regarding chemical resistance, a mortar cured product obtained by vibrating this mixture or a slice-shaped test piece (specimen) collected from a centrifugally molded cured product is immersed in a 5% aqueous sulfuric acid solution to improve the 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 shown in Table 1 below. The 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 for preventing shrinkage cracks. There are a total of 6 types of expansion materials that correspond to JIS A6202. Aggregate (coarse aggregate, fine aggregate), water, and a high-performance water reducing agent were kneaded with this to form this mixture.

(Mixing of this mixture)
As shown in FIG. 1, the fresh property of this mixture was a high flow type having a slump flow of 650 ± 50 mm. It was assumed that this would make a significant difference from vibration molding.
The amount of air in this mixture was set to 2.0 ± 1.5% as a target value from the measured value of the amount of air obtained at the time of freshness as a result of repeated test kneading.
As shown in Table 2 below, the composition of this mixture was a water powder ratio (W / P) of 34.0% and a fine aggregate ratio of 41.0%. In addition, Super Ash was used by substituting an amount corresponding to 5% of the total amount of powder with fine aggregate.

(Molding method of cured product)
After kneading the present mixture, a cured product was prepared by vibration molding and centrifugal molding.
In vibration molding, a tin columnar mold (φ100 x 200 mm) is filled with the present mixture in a fresh state in two layers, and the mixture is compacted in two layers while being vibrated by a table vibrator to cure the cylinder. The body was made.
In centrifugal molding, a mold for centrifugal molding (φ200 x 300 mm) is filled with the present mixture in a fresh state, the mold is rotated at high speed on a molding machine, and the mold 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, a centrifugally cured product was prepared by increasing the acceleration and compacting in several steps with the acceleration and molding time as shown in Table 3 below.

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

(Condensation time)
It was assumed that the curing reaction of this mixture would take a long time to set in the natural state. Therefore, as a coagulation test, the start time and end time were confirmed in the Proctor penetration resistance test. The mortar of the mixture used in this coagulation test is simply the coarse aggregate removed from the composition of this mixture shown in Table 2.
As shown in FIG. 3, the setting time of this mixture was about 14 hours for the first train and about 19 hours for the last train. This is thought to be due to the pozzolan reaction and latent hydraulic limeness.

(Steam curing condition)
Based on the results of the coagulation test, in order to understand the steam curing conditions (preposition time) effective for the strength development of the cured product, the effect of the preposition time in steam curing on the strength development of this mixture was confirmed. In this embodiment, the preamble time from water injection to the start of temperature rise is 4 hours, the rise temperature is 20 ° C / h, the maximum temperature is 65 ° C, the holding time is 4 hours, and the cooling is naturally lowered. I went under the conditions. At this time, the preposition time was divided into 5 levels shown in Table 4 below. That is, the preposition time was 0.5 hour (30 minutes), 1.5 hours, 3.0 hours, 6.0 hours, and 24.0 hours, and the other steam curing conditions were the same.

(Compression strength)
Table 5 below shows the test results of the compressive strength of the cured product by vibration molding and centrifugal molding, and by pre-preparation time and age.

FIG. 4 shows a graph of the results of vibration molding and FIG. 5 shows centrifugal molding. In each graph, the horizontal axis shows the preposition time and the vertical axis shows the compression strength (N / mm ² ). In addition, δ of each bar indicates the age (day). This clarified the difference between vibration molding and centrifugal molding.
Looking at the influence of the preposition time, the compression strength at the initial material age up to 14 days is low at the preposition of 0.5 hours, which is particularly remarkable at the material age of 1 day for vibration molding. There is a tendency similar to this between 1.5 hours in front and 3.0 hours in front, and the difference is small, and the compressive strength fluctuates with one day of vibration molding material age.
On the other hand, when the preposition time is 6.0 hours, the compressive strength is generally firmer than that of the one with a shorter preposition time, and in the centrifugal molding, the material age is 28 days and 40 N / mm ² The above compression strength is obtained. Furthermore, when the preposition time was 24.0 hours, the compression strength was at the highest level. Based on the results of the coagulation test described above, it was presumed that this was due to the fact that the pre-occurrence time was longer than the starting time of 14 hours of this mixture and was sufficiently secured.
As described above, the centrifugal molding was not affected by the pre-preparation time as much as the vibration molding, and the compressive strength was generally about 5 N / mm ² higher than that of the vibration molding.

Next, FIG. 6 shows a comparison of the strength ratios of vibration molding to centrifugal molding (100%) under each condition based on the above results.
Looking at this strength ratio, in vibration molding, the compressive strength of the cured product reacts sensitively to the preposition time, and in the case of short preposition times such as 0.5 hours, 1.5 hours, and 3.0 hours. The strength ratio was about 85%. On the other hand, in the preposition time of 6.0 hours or more, the strength ratio up to 14 days of age exceeded 90%, and the difference from the centrifugation was small up to this stage.
According to these results, centrifugal molding was able to shorten the pre-preparation time of the present mixture as compared with vibration molding. In addition, the compressive strength of the cured product was higher than that of vibration molding.

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

Further, in the same manner as in the coagulation test described above, a cured product (φ50 × 100 mm) was prepared by vibration molding using a mortar formulation obtained by simply removing the coarse aggregate from the formulation of the present mixture shown in Table 2.

The cured product made by OPC and the cured product of this mixture are immersed in a 5% sulfuric acid aqueous solution for 28 days in accordance with the "Quality test method for cross-section repair mortar of Japan Sewage Works Agency" to change the mass. Sulfuric acid resistance was evaluated from the appearance and appearance.
The amount (volume) of the 5% concentrated sulfuric acid aqueous solution is 1.96 L per test piece, and the surface area of the test piece and the volume ratio of the liquid (individual liquid ratio) are kept constant, and a new sulfuric acid aqueous solution is added every 7 days. The whole amount was replaced.

FIG. 7 shows the appearance of each specimen after being soaked for 28 days. FIG. 7 (a) is a specimen made of OPC, and FIG. 7 (b) is a specimen of a cured product of the present mixture.
The test results are shown in FIG. According to this, the mass of the OPC specimen decreased with the progress of the soaking days, and the mass change rate reached −32% in 28 days.
On the other hand, the cured product of this mixture was in a generally healthy state and showed excellent acid resistance, although slight cracks were generated.
However, the mass change rate after immersion for 28 days turned to the plus side by about 1%, and a slight expansion was confirmed in the cured product. Regarding this result, the minerals affecting the expansion and mass increase of the cured product of the cured product were identified by X-ray diffraction. As a result, gypsum produced from blast furnace slag (CaSO ₄ · 2H ₂ O) that is the main cause was estimated.

(Sulfuric acid resistance of cured product by centrifugation)
As described above, the results of the compressive strength test of the cured product composed of the present mixture showed that centrifugal molding was effective.
Based on this, a slice-shaped test piece was collected from the centrifugal specimen made of OPC having the formulation shown in Table 6 above and the cured product obtained by centrifuging the mixture, and the sulfuric acid resistance was evaluated.
In this sulfuric acid immersion test, the collected test piece was immersed in a 5% aqueous sulfuric acid solution for 28 days without considering the surface area of the test piece and the volume ratio (individual liquid ratio) of the solution.

FIG. 9 shows the appearance of each specimen after being soaked for 28 days. FIG. 9 (a) is a centrifugal specimen made by OPC, and FIG. 9 (b) is a centrifugal specimen of the present mixture.
The test results are shown in FIG. According to this, in the centrifugal test piece (centrifugal OPC) manufactured by OPC, a mass reduction of -16% and exposure of aggregate were confirmed in 28 days of immersion, and severe sulfuric acid deterioration occurred.
On the other hand, in the centrifugal specimen (centrifugal cured product) made of this mixture, although a mass loss of -0.8% was observed in 28 days of immersion, almost no change was observed in the appearance properties of the test piece, and it was sound. It was in a state.
In addition, fine cracks and slight expansions that occurred in the cured mortar produced by vibration molding were not observed, demonstrating the effectiveness of compacting the cured product by centrifugal molding.

(Summary)
In this example, in order to create a highly durable concrete product, hardened by centrifugation using a mixture containing no Portland cement and an industrial by-product mainly composed of fly ash and blast furnace slag fine powder. It was a body.
In this example, the following results were obtained:
(1) The curing reaction of this mixture was due to the pozzolan reaction and the latent hydraulic limeness, and the setting time was 14 hours for the first train and 19 hours for the last train.
(2) In the case of vibration molding, strength development and strength elongation are poor. For example, the compressive strength at 6 hours in advance and 28 days after age was 35.1 N / mm ² . On the other hand, centrifugal molding has good strength development and strength elongation. For example, the compression strength of 6 hours in advance and 28 days of age is 40.7 N / mm ² .
(3) Due to the delay in the setting time, in the case of vibration molding, when the pre-curing time of steam curing is 3.0 hours or less, the compression strength is at a lower level than 6.0 hours or more. However, when comparing 3.0 hours or less and 6.0 hours or more before the preposition time in centrifugal molding, the difference in compressive strength is smaller than that in vibration molding.
Therefore, by using centrifugal molding, the delay in the setting time of the present mixture can be offset, and it can be used for producing a practical Hume pipe. Specifically, it can be used in 1.5 hours or less.
(4) As a result of a 5% sulfuric acid immersion test on a mortar cured product by vibration molding and an OPC mortar specimen, the mass change rate of the OPC mortar specimen was -32%, whereas the mortar curing was performed. The body was almost healthy, although slight swelling was observed.
(5) As a result of a 5% sulfuric acid immersion test targeting a centrifugally cured product prepared by centrifugation and a centrifugal specimen manufactured by OPC, the mass loss of the centrifugal specimen manufactured by OPC was -16%. In the centrifugally cured product, the mass was reduced by only -0.8%, and the appearance was generally in a healthy state.

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

Further, FIG. 11 shows a graph of the relationship between the addition rate and the strength. In each graph, the horizontal axis indicates the percentage of addition rate (%) in weight percent with respect to the standard percentage. The vertical axis indicates the compression 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 (expansion material) 60 ~ 130%, S (fine aggregate) 80 ~ 125%, G (coarse aggregate) 80 ~ It was preferable to mix in a ratio of 125% and Ad (high-performance water reducing agent) 50 to 150%. These effects are as shown in the above-described embodiment.

(Sulfuric acid immersion test: Comparison of centrifugal cured product, OPC, BB, FC)
In Example 1, a centrifugally cured product and a centrifugal specimen made of ordinary cement (OPC) were described. In addition to this, a sulfuric acid immersion test using a standard blast furnace cement type B (BB) centrifugal specimen and a standard fly ash cement type C (FC) centrifugal specimen was performed in the same manner as in Example 1. It was.
FIG. 12 shows the appearance of deterioration of various centrifugal specimens. FIG. 12 (a) is a photograph of a blast furnace cement type B (BB) centrifugal specimen after immersion for 28 days, and FIG. 12 (b) is a photograph of a fly ash cement type C (FC) centrifugal specimen after immersion for 28 days. It is a photograph of. In each case, the appearance was severely deteriorated.
FIG. 13 shows a graph showing the degree of deterioration of various centrifugal specimens by immersing them in a sulfuric acid aqueous solution having a concentration of 5% for 28 days.
As a result, as a result of immersing various centrifugal specimens in a 5% aqueous sulfuric acid solution for 28 days, the mass change rate was 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 was possible to confirm the excellent sulfuric acid resistance of the cured products of these examples. did it.

(Strength development by mixing ratio of W / P and FA and BFS)
Next, the mixing ratio of fly ash (FA), which is the main material of the cured product, and blast furnace slag fine powder (BFS) was changed to 50% to 50% and 40% to 60%, and the mixture was produced 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 the strength when the mixing ratio of FA and BFS is 50%: 50%.
FIG. 15 shows a graph of the relationship between W / P and intensity in the result of FIG. Σ in this figure indicates the age (day) of the material.
FIG. 16 shows a graph of the 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. Σ in this figure indicates the age (day) of the material.

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

(Compressive strength of columnar cured product and centrifugal cured product)
The compression strength when the mixing ratio of fly ash (FA), which is the main material of the cured product, and blast furnace slag fine powder (BFS) was changed to 50% to 50% and 40% to 60%, was described in Example 1 and The water powder ratio (W / P) was changed between the similarly molded cylindrical cured product (φ100 × 200 mm) and the centrifugal cured product (φ200 × 300 mm) for comparison. The fresh properties of these cured products were 1.8% air volume and 10.0 cm slump.

FIG. 18 shows a graph of the compression strength when the mixing ratio of FA and BFS is 50%: 50%.
FIG. 19 shows a graph of the compression strength when the mixing ratio of FA and BFS is 40%: 60%.
As a result, as 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 specimen manufactured by centrifugal molding had a higher compressive strength than the cylindrical specimen manufactured by vibration molding, the tendency was similar to the result of Example 1.

(Effect of calcium hydroxide)
The compressive strength of the cured mortar (excluding the coarse aggregate) was compared by changing the amount of calcium hydroxide (Ca (OH) ₂ ) added as an alkaline stimulant (curing accelerator) of the cured product.
FIG. 20 shows a graph of the relationship between the amount of calcium hydroxide (Ca (OH) ₂ ) added and the compressive strength. Here, an experiment was conducted in which the addition rate of calcium hydroxide was changed under the conditions of W / P of 30%, flaash of 40%, and blast furnace slag fine powder of 60%.
From this result, when looking at the expression of compressive strength, the optimum amount of calcium hydroxide mixed is 20 kg / m ³ , and if it is less than that, the strength level is low, and even if it is mixed more than that, the strength cannot be increased. Do you get it.

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

FIG. 22 shows a graph of the experimental results of the relationship between the amount of calcium hydroxide and the depth of neutralization in the neutralization inhibitory effect test.
FIG. 23 shows a photograph of the color reaction of the cured product subjected to aerial 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 to which 20 kg / m ³ of calcium hydroxide was added. The neutralization depth was 7 mm. FIG. 23 (b) is a photograph of a 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 suppression effect test by this simple accelerated neutralization test apparatus, it was found that the neutralization depth of the cured product was remarkably reduced as the amount of calcium hydroxide mixed increased. That is, as a result, it was found that an effect of suppressing neutralization can be obtained by increasing the amount of calcium hydroxide (Ca (OH) ₂ ) added. That is, it is preferable to use 20 kg / m ^{3 of} Ca (OH) 2 (calcium hydroxide, slaked lime) as a standard formulation, and the content range for this is 50 to 500% (10 to 100 kg / m ³ ). is there.

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

(Manufacturing method of Hume pipe)
Next, as an example of precast concrete using the mixture of this example, a manufacturing method for manufacturing a Hume pipe by centrifugal molding will be described.
FIG. 25 shows the manufacturing process of the Hume pipe. In the manufacture of Hume pipes, a reinforcing bar basket knitted by combining reinforcing bars is installed in the formwork. Next, while rotating the mold on the molding machine, concrete mixed with a mixer is put in, and molding is performed while compacting with centrifugal force (low speed, medium speed, high speed). At this time, the inner surface of the Hume pipe is also finished at the same time. After that, the mold is steam-cured, slowly cooled, then demolded, and after a curing period, the appearance, dimensions, etc. of the Hume pipe are inspected before shipment.
In this embodiment, when the cured product is produced, the above-mentioned powder material is used instead of cement. In this way, when the actual cured product is manufactured by centrifugation, it can be carried out in the same manner as the manufacturing process of this Hume pipe.
In the case of vibration molding, precast concrete can be similarly produced by performing vibration molding during the "centrifugal molding / inner surface finishing" step of FIG. 25.

(External pressure test of the actual product of the centrifugally cured product)
As actual products of the centrifugally cured product, one having a diameter of 250 × 2000 mm and one having a diameter of 300 × 2000 mm were manufactured.
FIG. 26 shows the actual product of this centrifugally cured product and the test status. FIG. 26A is an appearance of an actual centrifugally cured product manufactured with a diameter of 300 × 2000 mm. FIG. 26B is a photograph showing the external pressure test status of the actual product of the centrifugally cured product.

The external pressure test was performed on a diameter of 250 × 2000 mm, and the actual product of the centrifugally cured product of this example and a conventional Hume pipe were performed in parallel.
FIG. 27 shows the results of an external pressure test of the actual product (φ250 × 2000 mm) of the centrifugally cured product of this example.
FIG. 28 shows the results (comparative example) of an external pressure test of a conventional Hume pipe (φ250 × 2000 mm).
As a result of the external pressure test, the actual product of the centrifugally cured product of this example fully satisfied the crack standard load and the fracture standard load as compared with the conventional Hume pipe. That is, it was confirmed that the product has good load bearing capacity. Furthermore, since the deflection is rather large, it is considered that brittle fracture is difficult.

(Application to vibration molded products)
Next, the present inventors manufactured an actual precast concrete product by the above-mentioned vibration molding, and examined the optimum blending ratio of the vibration molding product. Examples of this include box culverts and manholes.
Table 8 below shows compounding examples when the mixture of this example is applied to a centrifugal molded product (Hume pipe, etc.) and a vibration molded product (box culvert, etc.). Further, as shown in the formulation example of Table 8 as on-site construction, the mixture can be cast on-site if an appropriate curing method and temperature control are sufficiently performed.

In Table 8, Gmax is the maximum size of coarse aggregate, SL is slump flow, Air is the amount of air, W / P is the ratio of water (W) to total powder amount (P), and S / a is fine aggregate. Rate, S is fine aggregate, G is coarse aggregate, and Ad is admixture.
Here, in each 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.

Needless to say, the configuration and operation of the above-described embodiment are examples, and can be appropriately modified and executed without departing from the spirit of the present invention.

Claims (11)

Does not contain Portland cement
Water, industrial by-products, alkaline stimulants, swelling materials, fine aggregates, coarse aggregates, and high-performance water reducing agents are blended.
The industrial by-products include fly ash, blast furnace slag fine powder, and silica fume.
The alkali stimulant is acid-resistant concrete characterized by containing slaked lime . 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, the expanding material 30kg / m ³ , the fine aggregate at 639 kg / m ³ , the coarse aggregate at 959 kg / m ³ , and the high-performance water reducing agent at 5.434 kg / m ³ as standard formulations.
90-105% of the water, 10-110% of the fly ash, 90-190% of the blast furnace slag fine powder, 50-130% of the silica fume, 50-200% of the slaked lime, said expansion by weight percent. The claim is characterized in that the material is 60 to 130%, the fine aggregate is 80 to 125%, the coarse aggregate is 80 to 125%, and the high-performance water reducing agent is mixed in a ratio of 50 to 150%. acid-resistant concrete as described in 1. 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, the expanding material 30kg / m ³ , the fine aggregate at 639 kg / m ³ , the coarse aggregate at 959 kg / m ³ , and the high-performance water reducing agent at 5.434 kg / m ³ as standard formulations.
In percent by weight, 90-105% of the water, 10-110% of the fly ash, 90-190% of the blast furnace slag fine powder, 50-130% of the silica fume, 50-500% of the slaked lime, said expansion. The claim is characterized in that the material is 60 to 130%, the fine aggregate is 80 to 125%, the coarse aggregate is 80 to 125%, and the high-performance water reducing agent is mixed in a ratio of 50 to 150%. The acid-resistant concrete according to 2. Does not contain Portland cement
Water, industrial by-products, alkaline stimulants, swelling materials, fine aggregates, coarse aggregates, and high-performance water reducing agents are blended .
The industrial by-products include fly ash, blast furnace slag fine powder, and silica fume.
The alkaline stimulant contains slaked lime and contains
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, the expanding material 30kg / m ³ , the fine aggregate at 639 kg / m ³ , the coarse aggregate at 959 kg / m ³ , and the high-performance water reducing agent at 5.434 kg / m ³ as standard formulations.
In percent by weight, 90-105% of the water, 10-110% of the fly ash, 90-190% of the blast furnace slag fine powder, 50-130% of the silica fume, 50-500% of the slaked lime, said expansion. The acid resistance is characterized by blending 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 invention according to any one of claims 2 to 4 , wherein 26 kg / m ³ of sewage sludge incineration ash is used as a standard compound, and the sewage sludge incineration ash is compounded in a proportion of up to 200% by weight. Acid resistant concrete. A precast concrete produced from the acid-resistant concrete according to any one of claims 1 to 5 . The precast concrete according to claim 6 , wherein the precast concrete is a sewer pipe. Does not contain Portland cement
A mixture of water, industrial by-products, alkaline stimulants, swelling materials, fine aggregates, coarse aggregates, and high-performance water reducing agents.
The industrial by-products include fly ash, blast furnace slag fine powder, and silica fume.
The alkaline stimulant contains slaked lime and contains
An acid-resistant concrete manufacturing method characterized by compaction by centrifugal force molding, vibration molding, or casting by on-site construction. Does not contain Portland cement
Water, industrial by-products, alkaline stimulants, swelling materials, fine aggregates, coarse aggregates, and high-performance water reducing agents are blended.
Manufactured by vibration molding,
The industrial by-products include fly ash, blast furnace slag fine powder, and silica fume, and the alkaline stimulant contains slaked lime.
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, the expanding material 30kg / m ³ , the fine aggregate at 639 kg / m ³ , the coarse aggregate at 959 kg / m ³ , and the high-performance water reducing agent at 5.434 kg / m ³ as standard formulations.
90-105% of the water, 10-110% of the fly ash, 90-190% of the blast furnace slag fine powder, 50-130% of the silica fume, 50-500% of the slaked lime, said expansion by weight percent. The acid resistance is characterized by blending 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 manufacturing method . The acid-resistant concrete manufacturing method according to claim 8 or 9, wherein the concrete is steam-cured after molding, and the pre-curing time of the steam-curing is 1.5 hours or more. Does not contain Portland cement
Water, industrial by-products, alkaline stimulants, swelling materials, fine aggregates, coarse aggregates, and high-performance water reducing agents are blended.
It was cast on-site and
The industrial by-products include fly ash, blast furnace slag fine powder, and silica fume, and the alkaline stimulant contains slaked lime.
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, the expanding material 30kg / m ³ , the fine aggregate at 639 kg / m ³ , the coarse aggregate at 959 kg / m ³ , and the high-performance water reducing agent at 5.434 kg / m ³ as standard formulations.
90-105% of the water, 10-110% of the fly ash, 90-190% of the blast furnace slag fine powder, 50-130% of the silica fume, 50-500% of the slaked lime, said expansion by weight percent. 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.
A method for producing acid-resistant concrete, which comprises blending sewage sludge incineration ash 26 kg / m ³ as a standard blend as an industrial by-product, and blending the sewage sludge incineration ash in a proportion of up to 200% by weight.

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