JP5330895B2 - Molded product formed by molding mortar or concrete composition - Google Patents

Description

The present invention relates to a molded article formed by molding a mortar or concrete composition having excellent sulfuric acid resistance.

Conventionally, in an environment exposed to a sulfuric atmosphere such as a sewerage facility, the sulfuric acid resistance of the concrete used is required. For example, in a sewerage facility, sulfuric acid is produced by sulfur-oxidizing bacteria, and the concrete used in the sewage introduction channel of this type of facility may be corroded and deteriorated due to chemical erosion caused by this sulfuric acid. Are known. Therefore, there has been a demand for concrete having excellent sulfuric acid resistance that does not deteriorate even in such an environment.

For example, in Patent Document 1, cement having a particle size of 100 μm or less is 15 to 70% by weight, particle size 15
Cement part 20-70 which consists of 85-30 weight% of blast furnace quenching slag fine powder below micrometer
High strength and high durability mortar consisting of 80 parts by weight of blast furnace quenching slag having a particle size of 70 μm to 5.0 mm as fine aggregate, and a water reducing agent having a solid content of 4 wt% or less with respect to the cement part. A concrete composition is described. According to this, a mortar having high compressive strength can be provided, and the obtained mortar is said to have high durability. However, the sulfuric acid resistance is not necessarily excellent, and improvement has been desired.

In addition, in order to reduce the production of ettringite that causes deterioration, a pozzolanic substance such as silica fume and fly ash is added to concrete more than the amount of cement, and calcium hydroxide generated by the hydration reaction of cement is added. Although it was known to convert to CaO—SiO ₂ hydrate, in such a case, a large amount of pozzolanic material was used, so that there was a problem that the contraction was large and the concrete was easily cracked. In addition, since the amount of calcium hydroxide produced decreases, the resistance to sulfate ions increases, but there is a problem that erosion by hydrogen ions cannot be prevented, and improvement has been desired.

JP 61-281577 A1

The present invention has been made in view of the above, and is formed by molding a mortar or concrete composition having very excellent sulfuric acid resistance when used in an environment exposed to a sulfuric atmosphere such as a sewerage facility. The object is to provide a molded product .

In order to solve the above-described problems and achieve the object, a molded product formed by molding the composition for mortar or concrete according to claim 1 of the present invention includes a blast furnace slag fine aggregate (A) and water (W). , and ground granulated blast furnace slag (B) and Portland cement (C) binding material containing containing (D), met molded article obtained by molding the mortar or concrete composition is used in an environment exposed to sulfuric acid The blast furnace slag fine aggregate (A) is amorphous, the specific surface area of the blast furnace slag fine powder (B) is 2500 to 6500 cm ² / g in terms of Blaine, and Portland cement for the binder (D). The mass ratio (C / D) of (C) is 0.3-0.9, and the mass ratio (B / D) of the blast furnace slag fine powder (B) to the binder (D) is 0.1-0. 7 and 100 parts by mass of the binder (D) Wherein the furnace slag sand (A) 100 to 1000 parts by weight, wherein the binder (D). 25 to 42 parts by weight of water (W) with respect to 100 parts by weight of Portland cement (C) is an ordinary Portland cement The mass change rate after immersing the mortar or concrete specimen according to the mortar or concrete composition for 7 days in water and then immersing it in a sulfuric acid solution having a mass percentage concentration of 5% for 56 days was cured in water for 7 days. The mass change rate exceeds 100% based on the mass of the latter, and the mass change rate is a water binder ratio (W / D) which is a mass ratio of water (W) to binder (D), that is, the mortar or concrete feed. Regardless of the compressive strength of the specimen, it exceeds 100%, and the mortar or concrete specimen is in contact with sulfuric acid and has a dense dihydrate gypsum layer on its surface. All SANYO formed, said mortar or concrete composition, characterized in that it is obtained by steam curing.

  Moreover, the molded product which concerns on Claim 2 of this invention is used as sewer piping in Claim 1 mentioned above, It is characterized by the above-mentioned.

  The molded product according to claim 3 of the present invention is used as an offshore structure in claim 1 described above.

According to the composition for mortar or concrete of the present invention, when used in an environment exposed to a sulfuric acid atmosphere such as a sewerage facility, a dihydrate gypsum layer is formed on the mortar surface or the concrete surface, and the sulfuric acid resistance is very high. Are better. Moreover, the drying shrinkage of the mortar or concrete obtained is small. Furthermore, even when a crack occurs in mortar or concrete, an effect is achieved in that the crack can be self-repaired by a dihydrate gypsum layer newly generated on the surface.

FIG. 1 is a graph showing the rate of mass change of mortar in a sulfuric acid resistance test. FIG. 2 is a photograph of the mortar after the sulfuric acid resistance test in Example 1. FIG. 3 is a photograph of a mortar after a sulfuric acid resistance test obtained by changing the type of fine aggregate. FIG. 4 is a photograph of a mortar in a self-healing performance test, (a) is a photograph of the mortar of Example 1, (b) is a comparative example 6, and (c) is a photograph of a mortar of Comparative Example 7. FIG. 5 is a graph showing the change with time of the drying shrinkage strain, where (a) is a graph for standard curing and (b) is a graph for steam curing. FIG. 6 is a graph showing changes in final drying shrinkage strain with respect to mass ratio (C / D). FIG. 7 is a graph showing the change over time in the amount of expansion in the alkali aggregate reaction test. FIG. 8 is a graph showing changes in the relative kinematic modulus in the freeze-thaw resistance test. FIG. 9 is a graph showing the sulfuric acid resistance test results of the hardened cement. FIG. 10 is a partial cross-sectional view of a specimen showing an X-ray diffraction analysis line. FIG. 11 is a graph showing an element distribution by X-ray diffraction analysis, where (a) is a Ca amount, (b) is an S amount, (c) is an Fe amount, and (d) is an Al amount graph. FIG. 12 is a diagram showing a cycle of deterioration of the hardened cement body by sulfuric acid. FIG. 13 is a photograph of a mortar showing the protective effect of dihydrate gypsum from sulfuric acid. FIG. 14 is a photograph showing a sulfuric acid immersion test result of mortar using river sand. FIG. 15 is a photograph showing a sulfuric acid immersion test result of mortar using blast furnace slag fine aggregate. FIG. 16 is a graph showing the influence of the difference in fine aggregate on the pore size distribution of dihydrate gypsum. FIG. 17 is a photograph showing the effect of the vitrification rate of blast furnace slag fine aggregate on the sulfuric acid resistance of mortar. FIG. 18 is a graph showing the results of X-ray diffraction analysis of blast furnace slag fine aggregate. FIG. 19 is a photograph of the surface of the fine aggregate before and after being immersed in the calcium hydroxide aqueous solution, (a) is a photograph of the surface of river sand, and (b) is a photograph of the surface of the blast furnace slag fine aggregate. FIG. 20 is a photograph showing cross sections and surfaces of concrete using various coarse aggregates after immersion in sulfuric acid. FIG. 21 is a graph showing mass change rates of concrete using various coarse aggregates. FIG. 22 is a photograph showing the influence of the water binder ratio (W / D) on the concrete surface. FIG. 23 is a graph showing the effect of the water binder ratio (W / D) on the total pore volume of dihydrate gypsum. FIG. 24 is a graph showing the change in the erosion depth of the mortar with respect to the immersion period × sulfuric acid concentration. FIG. 25 is a graph showing the change in the erosion depth of concrete with respect to the immersion period × sulfuric acid concentration. FIG. 26 is a graph comparing changes in the relative mass of concrete with respect to the immersion period. FIG. 27 is a graph showing a change with time in the X-ray intensity of the blast furnace slag fine aggregate by the “judgment test of the aggregate forming the dihydrate gypsum film”. FIG. 28 is a graph showing the change over time in the relative mass of mortar obtained by changing the ratio of the crystallized blast furnace slag fine aggregate. FIG. 29 is a photograph showing a cross section of a mortar obtained by changing the ratio of the crystallized blast furnace slag fine aggregate after immersion in sulfuric acid. FIG. 30 is a graph showing time-dependent changes in X-ray intensity of various blast furnace slag fine aggregates according to the “judgment test for aggregates forming a dihydrate gypsum film”. FIG. 31 is a graph showing the change over time of the relative mass of mortar using various blast furnace slag fine aggregates. FIG. 32 is a photograph showing cross sections of mortar using various blast furnace slag fine aggregates after immersion in sulfuric acid. FIG. 33 is a graph showing the results of X-ray diffraction analysis of sewage sludge molten slag and copper slag. FIG. 34 is a graph showing changes in X-ray intensity of sewage sludge molten slag and copper slag over time according to the “judgment test of aggregate forming a dihydrate gypsum film”. FIG. 35 is a graph showing the change over time in the relative mass of mortar using sewage sludge molten slag.

Below, the example of the molded article formed by shape | molding the composition for mortar or concrete which concerns on this invention is described in detail based on drawing. Note that the present invention is not limited to the embodiments.

The composition for mortar or concrete of the present invention contains a blast furnace slag fine aggregate (A) and a binder (D) containing blast furnace slag fine powder (B) and Portland cement (C).

The blast furnace slag fine aggregate (A) used in the present invention is an amorphous blast furnace slag fine aggregate. As the amorphous blast furnace slag fine aggregate (A), granulated blast furnace granulated slag can be used, for example, by spraying pressurized water onto a blast furnace slag produced as a by-product in the iron making process and rapidly cooling it. Also,
The blast furnace slag fine aggregate (A) used in the present invention has a density of 2.5 to 3.0 g / cm ³ . Thus, a blast furnace slag fine aggregate having a density in the range of 2.5 to 3.0 g / cm ³ (
The present inventor has confirmed that by using A), the resulting mortar or concrete has excellent sulfuric acid resistance and low drying shrinkage strain. The reason for this is that when mortar or concrete is exposed to a sulfuric atmosphere, calcium ions (Ca ²⁺ ) are supplied at an appropriate rate and react with sulfate ions (SO ₄ ²⁻ ) to form mortar or concrete surfaces. This is probably because a dihydrate gypsum layer is formed. Here, the dihydrate gypsum layer formed in the present invention has a thickness of usually 0.01 mm or more. The thickness of dihydrate gypsum layer is 0.1m
m or more is preferable, and 1 mm or more is more preferable.

When the density of the blast furnace slag fine aggregate (A) is less than 2.5 g / cm ³ , since the blast furnace slag fine aggregate is porous, the strength of the mortar and concrete using it may be reduced. It is preferable that it is 0.55 g / cm ³ or more. On the other hand, when the density exceeds 3.00 g / cm ³ , material separation is likely to occur when fresh mortar and concrete are formed, and a partially inhomogeneous dihydrate gypsum may be formed, and the density is 2.90 g / cm 2. preferably cm ³ or less, more preferably 2.80 g / cm ³ or less. As can be seen from the examples below, when river sand, limestone crushed sand or electric furnace oxidation slag is used as the fine aggregate, a dihydrate gypsum layer is not formed, and the blast furnace slag fine aggregate (A) is used. The present inventor has confirmed that the sulfuric acid resistance is inferior to that of the case. Therefore, in order to form a dihydrate gypsum layer that can suppress deterioration of mortar or concrete when exposed to a sulfuric acid atmosphere, an amorphous blast furnace slag fine aggregate (A) is used as in the present invention. It is important to use.

The blast furnace slag fine powder (B) used in the present invention has a specific surface area of 2500 to 7 in terms of a brain value.
000 cm ² / g. Thus, the specific surface area is 2500 to 700 in terms of the brain value.
By using 0 cm ² / g blast furnace slag fine powder (B), a mortar or concrete composition having excellent sulfuric acid resistance can be obtained. When the specific surface area of the blast furnace slag fine powder (B) used is less than 2500 cm ² / g in terms of the brain value, the initial strength may be deteriorated, and the specific surface area is 3000 cm ² / g or more in terms of the brain value. Is preferred, 3500 cm
² / g or more is more preferable. On the other hand, the specific surface area is 7000 cm ² /
If it exceeds g, the cost increases, the heat of hydration increases, the drying shrinkage strain increases, and there is a risk of causing initial defects in the concrete, and the specific surface area is 6500 cm ² / g or less in terms of branes. It is preferably 5000 cm ² / g or less.

Examples of the Portland cement (C) used in the present invention include ordinary Portland cement, early-strength Portland cement, ultra-early strong Portland cement, moderately hot Portland cement, and low heat Portland cement. Among these, ordinary portland cement is more preferably used from the viewpoint of forming a dihydrate gypsum layer that can more effectively suppress deterioration of mortar or concrete when exposed to a sulfuric acid atmosphere.

The composition for mortar or concrete of the present invention contains an amorphous blast furnace slag fine aggregate (A) and a binder (D) containing blast furnace slag fine powder (B) and Portland cement (C). In the present invention, the mass ratio of the Portland cement (C) to the binder (D) (
C / D) is 0.3 to 0.9. At this time, blast furnace slag fine powder (B)
The mass ratio (B / D) between the binder and the binder (D) is preferably 0.1 to 0.7. Mass ratio (
When C / D) is within such a range, the resulting mortar or concrete has good sulfuric acid resistance. When the mass ratio (C / D) is less than 0.3, the film strength of dihydrate gypsum formed on the surface becomes weak, and it is difficult to suppress deterioration of mortar or concrete when exposed to a sulfuric acid atmosphere. The mass ratio (C / D) is preferably 0.35 or more, and the mass ratio (B / D) is more preferably 0.65 or less. On the other hand, the mass ratio (C
When / D) exceeds 0.9, in addition to dihydrate gypsum, expansive harmful ettringite is generated, and it may be difficult to suppress deterioration of mortar or concrete when exposed to sulfuric acid atmosphere. Yes, the mass ratio (C / D) is preferably 0.85 or less, and the mass ratio (
B / D) is more preferably 0.15 or more.

In the present invention, a total of 1 blast furnace slag fine powder (B) and Portland cement (C) 1
It is preferable that 50-1000 mass parts of blast furnace slag fine aggregates (A) are included with respect to 00 mass parts. When the content of the blast furnace slag fine aggregate (A) is less than 50 parts by mass, it may be difficult to suppress deterioration of the mortar or concrete when exposed to a sulfuric acid atmosphere.
More preferably, it is at least part by mass. On the other hand, the content of the blast furnace slag fine aggregate (A) is 100.
When it exceeds 0 parts by mass, it may be difficult to suppress deterioration of the mortar or concrete when exposed to a sulfuric acid atmosphere, and it is more preferably 800 parts by mass or less.
More preferably, it is 00 parts by mass or less.

In the composition for mortar or concrete of the present invention, amorphous blast furnace slag fine aggregate (A
), And a binder (D) containing blast furnace slag fine powder (B) and Portland cement (C)
In addition, the mortar composition usually further contains water, the concrete composition usually further contains water and coarse aggregate, and the mortar or concrete composition is cured to obtain mortar or concrete. Will be. Here, as usage-amount (W) of the water in the composition for mortars, it is preferable that water (W) is 25-70 mass parts with respect to 100 mass parts of binder (D). Moreover, it is preferable that water (W) is 25-60 mass parts with respect to 100 mass parts of binders (D) as usage-amount (W) of the water for concrete compositions, Use of coarse aggregate As an amount, the coarse aggregate is 100 to 100 parts by mass of the binder (D).
The amount is preferably 500 parts by mass. In addition, the mortar or concrete composition of the present invention may further contain other components as long as the effects of the present invention are not impaired.

The composition for mortar or concrete of the present invention is very useful for the construction of buildings and the like that require sulfuric acid resistance. For example, sewer piping, offshore structures, wastewater pitches in chemical factories, volcanic zones, hot springs, etc. It is preferably used in the field where sulfuric acid resistance is required. At this time, the composition for mortar or concrete of the present invention may be molded in advance and applied as a molded product, or the mortar surface or concrete surface is repaired using the mortar or concrete composition of the present invention. It does not matter. In particular, even when cracks occur in mortar or concrete, the cracks can be self-repaired by a dihydrate gypsum layer newly generated on the surface, and there is an advantage that maintenance is not required. By being constructed in this way, a dihydrate gypsum layer is formed on the surface of the mortar or concrete when the mortar or concrete is exposed to a sulfuric atmosphere, thereby providing mortar or concrete having excellent sulfuric acid resistance. .

  Hereinafter, the present invention will be described more specifically with reference to examples.

[Examples 1-6, Comparative Examples 1-9]
(Mortar mix)
While showing each material used by a present Example and a comparative example collectively in Table 1, Examples 1-6
Table 2 summarizes the mortar composition in Comparative Examples 1 to 9. In this example and comparative example, the blast furnace slag fine powder (B) (GGBS) has a brane value of 4250 cm ² /
A blast furnace slag fine powder 4000 manufactured by JFE Mineral Co., Ltd. having a density of 2.89 g / cm ³ was used. Silica fume (SF) has a density of 2.05 g / cm ³ SILICOM.
BECANCOUR Inc. Silica fume manufactured by a company (hereinafter abbreviated as “SBI”) was used. As fly ash (FA), JIS fly ash type II manufactured by Chuden Environmental Technos Co., Ltd. having a density of 2.2 g / cm ³ was used. The river sand (RS) has a density of 2.
61 g / cm ³ Asahikawa sand was used. Moreover, as the blast furnace slag fine aggregate (A) (BFS), a blast furnace slag fine aggregate manufactured by JFE Mineral Co., Ltd. having a density of 2.72 g / cm ³ was used. Also,
As a high-performance water reducing agent (SP) added to mortar for improving fluidity, Mighty 2
1VS (trade name, manufactured by Kao Corporation) was used.

(Test method)
The sulfuric acid resistance test, the compressive strength test, and the length change test for the mortars obtained in this example and the comparative example were performed according to the methods shown in Table 3 below.

Here, the sulfuric acid resistance test was performed by measuring a mass change rate in a sulfuric acid immersion test (neutralization depth) and a sulfuric acid immersion test. The sulfuric acid immersion test has a diameter of 50 mm and a height of 100 mm.
One cylindrical specimen was prepared and immersed in a 5% sulfuric acid solution for 56 days, and then the length of the discolored portion and the penetration depth were measured. The penetration depth was determined by measuring the neutralized depth by the phenolphthalein method. Also, the mass change rate is based on the mass after curing for 7 days in water using a specimen having the same dimensions and shape as the sulfuric acid immersion test.
The mass after immersion in a 5% strength sulfuric acid solution for 28 days and 56 days was measured to determine the rate of change. The results obtained are summarized in Table 4.

As is clear from the results in Table 4 above, the compressive strength at the age of 28 days may be lower in Examples 1 to 4 than in Comparative Examples 1 to 4, but for example, the sewage introduction path of a sewage facility And so on
When relatively high strength is not required, or when the mortar layer of the present embodiment is formed on the surface of the housing bearing the strength, a compressive strength with no practical problem is obtained. On the other hand, as is clear from the sulfuric acid immersion test results, in Comparative Examples 1 to 4, the smaller the water binder ratio, that is, the higher the strength, the greater the penetration of sulfuric acid, whereas in Examples 1 to 4 It can be seen that the penetration of sulfuric acid is small regardless of the water binder ratio, that is, the strength. Further, as is apparent from the measurement results of the mass change rate, in Examples 1 to 4, the change rate of the mass is very small, and Comparative Examples 1 to
Compared to 4, it can be seen that the erosion degradation with respect to sulfuric acid is greatly reduced.

Further, in the sulfuric acid resistance test of Example 1, Example 5, Example 6, Comparative Example 8 and Comparative Example 9 in which the mass ratio (C / D) of Portland cement (C) and binder (D) is different. The measurement results of the mass change rate are shown together in Table 5 below, and a graph is shown in FIG.

As can be seen from Table 5 and FIG. 1, the mass ratio (C / D) of Portland cement (C) and binder (D) is 0.3 to 0.9 without using blast furnace slag fine powder (B). Comparative Example 8 not within
In Comparative Example 9 where the mass ratio (C / D) is not in the range of 0.3 to 0.9, the mass change rate after being immersed in a 5% strength sulfuric acid solution for 56 days was 89.1%, respectively. It is 88.3% and it turns out that the erosion degradation with respect to a sulfuric acid is seen. On the other hand, Examples 1, 5 and 6 in which the mass ratio (C / D) of Portland cement (C) and binder (D) is within the range of 0.3 to 0.9.
In any case, the mass change rate exceeds 100%, and it can be seen that the sulfuric acid resistance is excellent. This is because, as shown in FIG. 2, a dihydrate gypsum film is formed on the surface of the mortar by reacting both the binder (D) and the blast furnace slag fine aggregate (A) with sulfuric acid. This is thought to be due to the significant improvement in sulfuric acid resistance.

[Comparative Examples 10 and 11]
(Mortar blending and sulfuric acid resistance test)
Mortar was produced in the same manner as in Comparative Example 1 except that the type of fine aggregate was changed without using the blast furnace slag fine powder (B). The mortar blends of Comparative Examples 1, 8, 10 and 11 are summarized in Table 6 and the mass in a sulfuric acid immersion test (neutralization depth) and sulfuric acid immersion test after being immersed in a 5% strength sulfuric acid solution for 56 days. Table 7 summarizes the rate of change.

As can be seen from the results in Table 7 above, compared to Comparative Example 1 using river sand as fine aggregate, Comparative Example 10 using limestone crushed sand, and Comparative Example 11 using electric furnace oxidation slag, In Comparative Example 8 using the blast furnace slag fine aggregate (A), the mass change rate was not large, and the erosion depth was small as can be seen from the photograph in FIG.

Table 8 shown below shows the measurement results and mass change by the phenolphthalein method of the sulfuric acid immersion test conducted for Example 1 and Comparative Example 5, respectively.

As can be seen from Table 8 above, even if the constituent members of the binder (D) used are the same, compared to Comparative Example 5 in which river sand is used for the fine aggregate, the blast furnace slag fine aggregate ( In Example 1 using A), it was found that the erosion depth was small and the mass change rate was small, so that the sulfuric acid resistance was excellent. As can be seen from the mortar photograph in FIG. 2, this is because the hydrate slag fine aggregate (A) and the binder (D) both react with sulfuric acid on the mortar surface. It is thought that the sulfuric acid resistance of the mortar is greatly improved.

Table 9 shown below shows the measurement results and mass change of the sulfuric acid immersion test conducted in Example 1, Comparative Example 6 and Comparative Example 7 by the phenolphthalein method.

As can be seen from Table 9 above, fly ash and silica fume are used in addition to the blast furnace slag fine powder (B) as the binder, river sand is used as the fine aggregate, and the mass ratio (C / D) is 0.3 to In addition to Comparative Example 6 which was not within the range of 0.9 and the blast furnace slag fine powder (B) as the binder (D), fly ash and silica fume were further used, and the mass ratio (C / D) was 0.3. Compared with Comparative Example 7 that was not in the range of ˜0.9, the mortar obtained by Example 1 of the present invention was superior in sulfuric acid resistance because the erosion depth was small and the mass change rate was also small. I understand that.

Table 10 shown below was obtained for Example 1, Comparative Example 1 and Comparative Example 6 by measuring the length of the same portion on the 10th and 91st drying periods with a material age of 7 days as the base length. The measurement result of the rate of change in length is shown. This length change test was based on JIS A 1129-3 (Mortar and concrete length change test method-Part 3: Dial gauge method).

As can be seen from Table 10, Comparative Example 6 using a large amount of pozzolanic material as the binding material has the largest shrinkage, and the length change rate is smaller in Comparative Example 1 and Comparative Example 6 in Example 1 of the present invention. I understood.

Further, Example 1, Comparative Example 6 and Comparative Example 7 were immersed in a sulfuric acid solution having a concentration of 5% from the age of 7 days for 28 days, then a cut having a thickness of 3 mm and a depth of 30 mm was made, and further immersed for 14 days. The mortar surface after observation was observed. The obtained results are shown in FIG. As can be seen from the photographs in FIG. 4A, which were observed before and after the change in the surface of the mortar of Example 1, compared to FIG. 4B of Comparative Example 6 and FIG. In No. 1, a dihydrate gypsum film is formed not only on the surface of the mortar but also on the cut line, and even if cracks occur, self-healing is done by the new dihydrate gypsum on the surface in contact with sulfuric acid, preventing the penetration of sulfuric acid. It is inferred that this is possible.

[Examples 7 to 9, Comparative Examples 12 to 14]
(Concrete mix)
The concrete blends in Examples 7 to 9 and Comparative Examples 12 to 14 are shown together in Table 11, and the measurement results of mass change rate in the compressive strength and sulfuric acid resistance test of the obtained concrete are shown together in Table 12. .

[Various Properties of the Composition for Mortar or Concrete of the Present Invention]
(Dry shrinkage strain)
Next, the drying shrinkage strain of the mortar of the present invention will be described with reference to FIGS.
FIG. 5 is a graph showing the change over time in the drying shrinkage strain.
b) is a graph in the case of steam curing.

In the figure, BB40 (blast furnace slag) is a blast furnace slag finely mixed with 40% water binder ratio cement paste using a mixture of ordinary Portland cement and blast furnace slag fine powder in a mass ratio of 4: 6. The result of the mortar which mixed the aggregate is shown. In addition, BB40 (
Shows the results of mortar in which river sand is mixed with 40% water binder cement paste using a mixture of ordinary Portland cement and ground granulated blast furnace slag at a mass ratio of 4: 6. ing. Moreover, OPC (river sand) in the figure shows the result of mortar in which river sand is mixed with cement paste having a water cement ratio of 40% using only ordinary Portland cement as a binder.

As shown in FIG. 5, the OPC (river sand) does not change much in the drying shrinkage strain regardless of the standard curing or the steam curing. On the other hand, BB40 (blast furnace slag) corresponding to the configuration of the present invention has a drying shrinkage strain of 200 days or less in the drying period 100 days in the case of steam curing, which is smaller than the drying shrinkage strain of OPC (river sand). .

FIG. 6 is a graph showing an example of a change in final drying shrinkage strain with respect to the mass ratio (C / D) of the mortar of the present invention. As shown in FIG. 6, it can be seen that the final drying shrinkage strain of the mortar of the present invention is smaller in the steam curing than in the standard curing. According to the present invention, even if cracking occurs due to such drying shrinkage strain, the base material is protected from erosion by sulfuric acid by the dihydrate gypsum film formed on the surface. For this reason, the mortar or concrete composition of the present invention is also useful as a repair material for mortar or concrete exposed to a sulfuric acid environment.

(Alkali aggregate reaction)
Next, the alkali aggregate reaction of the concrete composition of the present invention will be described with reference to FIG. FIG. 7 is a graph showing the change over time in the amount of expansion in the alkali aggregate reaction test.
As shown in FIG. 7, in the case of ordinary concrete, the expansion amount exceeds 0.1% in 3 months. On the other hand, in the case of the sulfate resistant concrete corresponding to the constitution of the present invention using the same aggregate, there is almost no expansion amount even after 3 months, and the alkali aggregate reaction may hardly occur. I understand.

(Freeze-thaw resistance performance)
Next, the freeze-thaw resistance performance of the concrete composition of the present invention will be described with reference to FIG. FIG. 8 is a graph showing changes in the relative kinematic modulus in the freeze-thaw resistance test.
As shown in FIG. 8, it can be seen that the concrete of the present invention can secure the freeze-thaw action without mixing a large amount of air unlike AE concrete.

[Detailed Experiments Regarding Actions and Effects of the Present Invention]
Next, the action and effect of the mortar or concrete composition of the present invention will be described in more detail with reference to FIGS.

First, calcium sulfate (gypsum) is produced by the reaction between concrete and sulfuric acid. If this reaction occurs at 66 ° C. or higher, anhydrous gypsum is produced, and if it is 66 ° C. or lower, dihydrate gypsum is produced. Therefore, in an environment such as a sewer, the deterioration of concrete caused by sulfuric acid is accompanied by dihydrate gypsum. Dihydrate gypsum reacts with tricalcium aluminate in cement to produce ettringite and cause concrete deterioration (
For example, Reference 1 “Edited by Japan Sewerage Corporation: Corrosion Inhibition Technology and Anticorrosion Technology Manual for Sewerage Concrete Structures, Sewerage Business Management Center, pp. 12-17, 200
7.7 ").

On the other hand, dihydrate gypsum has the effect of blocking concrete pores when sulfuric acid concentration is low, and it prevents elution of decomposition products by sulfuric acid and prevents sulfuric acid from penetrating into concrete. It is also said that there is an action and an effect of preventing erosion (for example, Reference 2 “Kunio Mizukami: Durability Series of Concrete Structures, Chemical Corrosion, Gihodo Publishing, p. 22)
1986.12 ").

This experiment shows that the resistance to sulfuric acid of mortar and concrete can be increased by using blast furnace slag fine powder and blast furnace slag fine aggregate. The dihydrate gypsum produced by the reaction between sulfuric acid and hardened cement has the effect of suppressing the erosion of the hardened cement by sulfuric acid, and if blast furnace slag fine aggregate is used, it peels off around the healthy parts of mortar and concrete. The following shows that a difficult dihydrate gypsum film is formed and the sulfuric acid resistance is improved.

[Experiment Overview]
(Materials used)
For the binder, ordinary Portland cement (density: 3.15 g / cm ³ , brain value: 3
300 cm ² / g) and blast furnace slag fine powder (density: 2.89 g / cm ³ , brain value: 4)
150 cm ² / g) was used. For fine aggregate, river sand (density: 2.61 g / cm ³ , water absorption:
1.96%, coarse grain ratio: 2.96) and blast furnace slag fine aggregate (density: 2.77 g / cm ³ , water absorption: 0.72%, coarse grain ratio: 2.15) were used. For coarse aggregate, sandstone crushed stone (density: 2.7
5 g / cm ³ , water absorption: 0.54%, unit volume mass: 1640 kg / m ³ , limestone crushed stone (density: 2.71 g / cm ³ , water absorption: 0.35%, unit volume mass: 1590 kg / m ³
) And blast furnace slow-cooled slag coarse aggregate (density: 2.63 g / cm ³ , water absorption: 4.71%).

(Sulfuric acid immersion test)
For sulfuric acid immersion test, φ50 × 100mm, φ75 × 150mm and φ100 × 200m
m cylindrical specimens were used. After demolding, the specimen was cured in water until the age of 7 days and immersed in 5% sulfuric acid at a mass percentage concentration. It was washed with water every 7 days, the deteriorated portion was removed, and the mass was measured. Further, the specimen immersed in sulfuric acid for 56 days was cut with a dry cutter, sprayed with a phenolphthalein solution, and the diameter of the colored area of the cut surface was measured.

[Experimental results and discussion]
(Deterioration of cement paste by sulfuric acid)
FIG. 9 shows the mass change due to sulfuric acid in cement paste using ordinary Portland cement and blast furnace slag fine powder as a binder. In the figure, ◯ and ● indicate the results of a cement paste (hereinafter referred to as OPC30 and OPC60) having a water cement ratio of 30% and 60%, respectively, using only ordinary Portland cement as a binder. Also, □ in the figure
And black □ are cement pastes having a water binder ratio of 30% and 60%, respectively, using a mixture of ordinary Portland cement and blast furnace slag fine powder in a mass ratio of 4: 6. The results of BB30 and BB60) are shown.

As shown in FIG. 9, the mass of OPC30 decreased linearly, and decreased to 28.0% of the mass before immersion 56 days after the start of immersion. The OPC 60 gradually decreases in mass while repeatedly increasing and decreasing in mass. On the other hand, in BB30, the mass increases once,
Since then it has decreased. In addition, the mass of BB60 continues to increase until the immersion period of 56 days.

When a phenolphthalein solution was sprayed on the cross section of the cement paste soaked in sulfuric acid for 56 days, when only ordinary Portland cement was used as the binder, OPC60 having a large water cement ratio had phenolphthalein on the surface of the specimen. A white layer that was not discolored by the solution was confirmed. On the other hand, BB30 and BB60 using a blast furnace slag fine powder as a part of the binder.
In any water binder ratio, a white layer that was not discolored by the phenolphthalein solution was formed on the surface of the specimen. It was confirmed that BB30, BB60, and OPC60 in which a white layer was confirmed had a smaller depth of erosion by sulfuric acid than OPC30 in which no white layer was observed. It was confirmed by X-ray diffraction analysis that this white layer was mainly composed of dihydrate gypsum. In addition, FIG. 10 is sectional drawing to which the surface part of the test body containing a white layer was expanded. FIG. 11 shows the result of examining the element distribution on the analysis line of FIG. 10 by X-ray diffraction analysis.

Next, FIG. 12 shows a cycle of sulfuric acid deterioration based on the result of observing the deterioration of the cement paste in sulfuric acid. When the cement paste is immersed in sulfuric acid, a dihydrate gypsum film is formed on the surface in contact with the sulfuric acid (FIG. 12B). Eventually, dihydrate gypsum reacts with tricalcium aluminate in the cement to produce ettringite (FIG. 12 (c)). Ettringite is stable on the high pH side close to the healthy part of the cement paste, but on the low pH side close to the specimen surface, it changes into a putty-like dihydrate gypsum (FIG. 12 (d)) (for example, , See reference 1 above).

When the putty-like dihydrate gypsum produced by the reaction between ettringite and sulfuric acid increases, the hard dihydrate gypsum on the surface of the specimen peels off from the healthy part (FIG. 12 (e)). Ettlingite remaining in the vicinity of the healthy portion of the paste is also exposed to an environment having a low pH, and changes into a putty-like dihydrate gypsum (FIG. 12 (f)). The putty-shaped dihydrate gypsum easily peels off the healthy part,
The healthy part comes into contact with sulfuric acid, and a new deterioration cycle starts (FIG. 12A). The OPC 60 shown in FIG. 9 seems to have repeated the cycle shown in FIG. 12 twice. OPC30
It seems that the mass decreased linearly because the deterioration cycle shown in FIG. 12 was repeated at very short intervals.

When the sulfuric acid immersion test was continued on the cylindrical specimen placed in the sulfuric acid without removing the dihydrate gypsum caused by the deterioration with sulfuric acid, it was covered with the dihydrate gypsum as shown in the photograph of FIG. The degree of erosion differs between the covered and uncovered parts. The upper diameter of the specimen is 6
The diameter of the lower part of the specimen covered with dihydrate gypsum is 81.4mm, while it is 5.0mm.
It is. As a result of measuring the calcium ion concentration in the sulfuric acid in which the specimen was immersed with an atomic absorption photometer, the calcium ion concentration in the solution was 179 mg / L, whereas in the inside where the dihydrate gypsum was deposited, 200 mg / L L. Inside the dihydrate gypsum deposit, the calcium ion concentration is high, and compared to the place where the dihydrate gypsum is not deposited, there is less elution of calcium ions from the concrete, and erosion by sulfuric acid is suppressed. Conceivable.

(Sulfate resistance of mortar)
The photograph in FIG. 14 is a result of spraying phenolphthalein on the cross section after dipping mortar using river sand in sulfuric acid for 56 days. In mortar using river sand, blast furnace slag fine powder and ordinary Portland cement were used as the binder. Only when the water binder ratio is 60%, a dihydrate gypsum film can be confirmed around the specimen. On the other hand, from the photograph of FIG. 15 in which mortar using blast furnace slag fine aggregate was immersed in sulfuric acid for 56 days, a dihydrate gypsum film remained on the surface of the specimen when any binder was used. I understand that. As shown in these photographs, the mortar in which the dihydrate gypsum film is confirmed on the surface of the specimen has a smaller depth of erosion by sulfuric acid than the mortar in which the dihydrate gypsum film cannot be confirmed.

In addition, when BB60 was added to river sand and blast furnace slag fine aggregate, mortar dihydrate gypsum film was observed. As a result, dihydrate gypsum film on the surface of mortar using blast furnace slag fine aggregate was river sand. It was confirmed to be dense compared to the dihydrate gypsum film on the mortar surface.

FIG. 16 is a comparison of the pore size distribution of dihydrate gypsum produced on these mortar surfaces. From this figure as well, the dihydrate gypsum film on the mortar surface using blast furnace slag fine aggregate is river sand. It can be seen that it is denser than the dihydrate gypsum film on the surface of the mortar. In addition, pore diameter distribution measured the pore of the range of 3 nm to 120,000 nm by the mercury intrusion method.

As shown in the photographs of FIGS. 14 and 15, the size of the healthy portion that is discolored by the phenolphthalein solution after the sulfuric acid immersion period of 56 days was 37.3 mm in the mortar using river sand, whereas the blast furnace The mortar using slag fine aggregate is 44.7 mm. It can be said that the depth of erosion by sulfuric acid is smaller in mortars using blast furnace slag fine aggregates where dense dihydrate gypsum is made than in mortars using river sand.

The photograph of FIG. 17 is a blast furnace slag fine aggregate heated to 1000 ° C. and crystallized, and an amorphous ordinary blast furnace slag fine aggregate in a mass ratio of 100: 0 (indicated as 0% in the figure), 50:50 (5 in the figure
This is a photograph of the deterioration after mortar using fine aggregate mixed at a ratio of 0% and 0: 100 (indicated as 100% in the figure) was immersed in sulfuric acid for 14 days. As is clear from this photograph, even if the components are the same blast furnace slag fine aggregate, the dihydrate gypsum film formed on the surface of the mortar using the crystallized blast furnace slag fine aggregate is easy to peel off. I understand that there is. In addition, the X-ray-diffraction analysis result of the blast furnace slag fine aggregate heated to 1000 degreeC used for this experiment and the general blast furnace slag fine aggregate is shown in FIG. It can be seen that by heating to 1000 ° C., the amorphous blast furnace slag fine aggregate is crystallized.

19A and 19B were taken with a scanning electron microscope, respectively, before and after immersing river sand and blast furnace slag fine aggregate in a saturated calcium hydroxide aqueous solution. Is. A hexagonal plate-like crystal of calcium hydroxide is confirmed on the surface of the river sand after being immersed in the saturated calcium hydroxide aqueous solution. On the other hand, crystals of a C—S—H cured body have been confirmed on the surface of the blast furnace slag fine aggregate after being immersed in the saturated calcium hydroxide aqueous solution. In the case of aggregates that are crystalline and have low reactivity, such as river sand, dihydrate gypsum produced by the reaction of calcium hydroxide accumulated around the aggregate with sulfuric acid is considered to be weak in strength.

On the other hand, if an amorphous blast furnace slag fine aggregate is used, the surface of the blast furnace slag fine aggregate is made of a C—S—H hardened body due to a reaction with calcium hydroxide generated by a hydration reaction of cement. It is thought that dihydrate gypsum film is formed on the surface where mortar and sulfuric acid come into contact with each other. .

(Sulfuric acid resistance of concrete)
After observing the condition after immersing concrete containing blast furnace slag fine aggregate in sulfuric acid for 56 days in all fine aggregates, pop-out and coarse aggregate that seems to be due to the expansion of ettringite on the concrete surface Peeling of mortar around was confirmed. As in the case of mortar using river sand as fine aggregate, it is inferred that calcium hydroxide accumulates around the coarse aggregate and that part of the dihydrate gypsum membrane is damaged.

The photograph of FIG. 20 shows the result of immersing concrete using sandstone crushed stone, limestone crushed stone and blast furnace slow-cooled slag coarse aggregate in sulfuric acid for 56 days. In any concrete, blast furnace slag fine powder and ordinary Portland cement are used as the binder, and only blast furnace slag fine aggregate is used as the fine aggregate. The unit water amount is 175 kg / m ³ , the water binder ratio is 25%, the cement binder ratio is 40%, and the fine aggregate ratio is 45.0%. Deterioration such as pop-out is confirmed on the surface of the concrete using any coarse aggregate. However, the depth of sulfuric acid erosion into the concrete is as small as 1.7 mm to 2.3 mm in an immersion period of 56 days.

In addition, the mass change of these concretes is compared with the mass change of concrete with 25% water cement ratio using ordinary Portland cement as binder, river sand as fine aggregate and sandstone crushed stone as coarse aggregate. The results are shown in FIG. In the figure, ◯, □, and Δ are the results of using sandstone crushed stone, limestone crushed stone, and blast furnace slow-cooled slag coarse aggregate as the coarse aggregate, respectively. The ● in the figure is the result of concrete using ordinary Portland cement, river sand and sandstone crushed stone. Even if blast furnace slag fine aggregate is used for all of the fine aggregates, breakage occurs in the dihydrate gypsum film formed on the concrete surface using the coarse aggregate with high crystallinity. However, the resistance to sulfuric acid determined by mass change is much higher than that using river sand as fine aggregate.

The photograph of FIG. 22 is the result of investigating the influence of the water binder ratio on the sulfuric acid degradation of concrete using blast furnace slag fine aggregate as the fine aggregate. It can be seen that the smaller the water binder ratio, the less the surface degradation. FIG. 23 shows the relationship between the total pore volume of the dihydrate gypsum membrane produced by the reaction with sulfuric acid on the surface of the concrete using the blast furnace slag fine aggregate and the water binder ratio. The pore size distribution is 3 nm to 120,000 nm by mercury porosimetry.
The pores in the range are measured. From this figure, it can be seen that the smaller the water binder ratio, the smaller the total pore volume. That is, if the water binder ratio is reduced, a dense dihydrate gypsum is produced, and it is considered that the number of damaged portions generated in the dihydrate gypsum membrane is reduced.

(Summary of experiment)
Dihydrate gypsum film formed on the surface of mortar and concrete in contact with sulfuric acid has the effect of suppressing erosion by sulfuric acid. However, when using highly crystalline aggregates, calcium hydroxide produced by cement hydration accumulates around the aggregates, producing weakly dihydrated gypsum, and dihydrated gypsum membrane. It becomes easy to peel off. On the other hand, when amorphous blast furnace slag fine aggregate is used for all fine aggregates, a dense dihydrate gypsum film can be formed, and erosion against sulfuric acid can be greatly suppressed. . Even if blast furnace slag fine aggregate is used for all fine aggregates, when coarse aggregate with high crystallinity is used, a defect portion is generated in the membrane of dihydrate gypsum. However, the results of immersion in sulfuric acid at a concentration of 5% for 56 days indicate that if blast furnace slag fine aggregate is used for all fine aggregates, it is significantly more resistant to sulfuric acid than concrete using river sand. It is possible to manufacture concrete with

[Characteristics such as immersion period x erosion depth for sulfuric acid concentration]
Next, characteristics such as erosion depth with respect to immersion period × sulfuric acid concentration will be described with reference to FIGS.

(Erosion depth)
FIG. 24 is a graph showing the change in the erosion depth of the mortar with respect to the immersion period × sulfuric acid concentration. FIG. 25 is a graph showing the change in the erosion depth of concrete with respect to the immersion period × sulfuric acid concentration. Table 13 summarizes the measurement results of the erosion depths of ordinary mortar, sulfate-resistant hydrated solidified mortar corresponding to the constitution of the present invention, ordinary concrete and sulfuric acid-resistant hydrated solidified corresponding to the constitution of the present invention. .

As shown in FIG. 24, it can be seen that the erosion depth by sulfuric acid is smaller than that of ordinary mortar in the case of sulfuric acid-resistant hydrated solidified mortar, and has a sulfuric acid resistance of about 7 times. Moreover, as shown in FIG. 25, in the case of a sulfuric acid resistant hydrated solid body, it turns out that it has a sulfuric acid resistance of about 6 times compared with normal concrete.

(Comparison with conventional technology)
FIG. 26 is a graph comparing changes in the relative mass of concrete with respect to the immersion period.
This figure shows the results of the sulfuric acid-resistant hydrated solidified body corresponding to the constitution of the present invention, ordinary concrete as a comparison object, and the conventional technique (test number 9 shown in Patent Document 1 above). is there.
Table 14 shows the relative mass (%), and Table 15 shows the composition. As shown in FIG. 26, the relative mass of the sulfate-resistant hydrated solidified body of the present invention does not decrease with the passage of sulfuric acid immersion period as in ordinary concrete or the prior art, compared to ordinary concrete or the prior art. It turns out that it is excellent in sulfuric acid resistance.

[Judgment test of aggregate forming dihydrate gypsum film]
Next, a test for determining whether or not the blast furnace slag fine aggregate is a blast furnace slag fine aggregate (A) capable of sufficiently exhibiting the action of forming a dihydrate gypsum film when immersed in sulfuric acid (two water (Aggregate determination test for forming a gypsum film) will be described.

As a procedure of this test, first, a sample (fine aggregate) is screened into 0.3 to 0.6 mm particles, each 0.20 g is weighed, and each sample is put into a test tube (φ12 × 120 mm). Then, 4 ml of a sulfuric acid solution having a mass percent concentration of 5% is added to each test tube containing the sample. Subsequently, the sample is immersed for 15 minutes, 30 minutes, 45 minutes, and 60 minutes. After each immersion time, the sample is taken out on the filter paper (5B) set in the funnel, and washed 8 times with distilled water. After the washing is completed, the sample together with the filter paper is transferred to an aluminum container and dried in a vacuum dryer at 50 ° C. for 12 hours. After drying, the sulfur content is measured by fluorescent X-ray analysis without losing the shape of the sample.

If a sufficient sulfur content is found as a result of this measurement, the sample is judged to be a blast furnace slag fine aggregate (A) that can sufficiently exhibit the action of forming a dihydrate gypsum film when immersed in sulfuric acid. It can be used as the blast furnace slag fine aggregate (A) for the mortar or concrete composition of the present invention.

Next, an example of the test results of the blast furnace slag fine aggregate, sewage sludge molten slag and copper slag by the “judgment test of the aggregate forming the dihydrate gypsum film” will be described.

(Blast furnace slag fine aggregate)
Using an amorphous blast furnace slag fine aggregate having an X-ray intensity distribution as shown in FIG. 18 and a crystallized blast furnace slag fine aggregate, a “determination test of the aggregate forming a dihydrate gypsum membrane” FIG. 27 and Table 16 show the results of performing “”. The measured sulfur adsorption amount is shown by X-ray intensity. As shown in FIG. 27 and Table 16, amorphous blast furnace slag fine aggregate has a large amount of sulfur adsorption.
On the other hand, it can be seen that the crystallized blast furnace slag fine aggregate increases in the amount of sulfur adsorbed as the sulfuric acid immersion time elapses.

FIG. 28 is a graph showing the change over time in the relative mass of mortar obtained by changing the ratio of the crystallized blast furnace slag fine aggregate. It is immersed in sulfuric acid having a concentration of 5%. Table 17 shows the measurement results of the relative mass (when the proportions of crystallized blast furnace slag fine aggregate are 0% and 100%). FIG. 29 is a photograph showing a cross section of the mortar obtained by changing the ratio (α) of the crystallized blast furnace slag fine aggregate after immersion in sulfuric acid (immersion period 28 days). As shown in FIG. 28 and FIG. 29, the mortar with a higher ratio (α) of the crystallized blast furnace slag fine aggregate has a larger decrease rate of the relative mass, and the mortar with a lower ratio (α) has a decrease rate of the relative mass. It is small and excellent in sulfuric acid resistance.

(Various blast furnace slag fine aggregates)
FIG. 30 and Table 18 show the results of the “judgment test for aggregates forming a dihydrate gypsum film” for three generally available products, raw materials before grinding, and three blast furnace slag fine aggregates for earthwork. It is. The measured sulfur adsorption amount is shown by X-ray intensity. In the above, “raw material” and “
The difference in “product” is whether or not a grinding process (a process of removing glass thorns) is performed, and reactive activation is not performed. "For earthwork" has a remarkably low basicity compared to "product" and "raw material".

FIG. 31 is a graph showing the change over time of the relative mass of mortar using various blast furnace slag fine aggregates. It is immersed in sulfuric acid having a concentration of 5%. Table 19 shows the measurement results of the relative mass. FIG. 32 is a photograph showing a cross section of mortar using various blast furnace slag fine aggregates after immersion in sulfuric acid (immersion period 56 days). As shown in FIG. 30 to FIG. 32, the aggregate that has been confirmed to adsorb sulfur in the “judgment test of the aggregate that forms a dihydrogypsum membrane”, regardless of basicity and the presence or absence of grinding treatment, It turns out that it forms dihydrate gypsum and improves sulfuric acid resistance.

(Sewage sludge melting slag and copper slag)
FIG. 33 is a graph showing the results of X-ray diffraction analysis of sewage sludge molten slag and copper slag. As shown in FIG. 33, both sewage sludge molten slag and copper slag can be called amorphous aggregates. FIG. 34 and Table 20 show the results of performing the “judgment test for the aggregate forming the dihydrate gypsum membrane” for these aggregates. The measured sulfur adsorption amount is shown by X-ray intensity. As shown in FIG. 34 and Table 20, sulfur adsorption is not observed in both the sewage sludge molten slag and the copper slag.

FIG. 35 is a graph showing the change over time in the relative mass of mortar using this sewage sludge molten slag. As shown in FIG. 35, it can be seen that the relative mass decreases with time by immersion in sulfuric acid having a concentration of 5%. From these results, even if it is an amorphous aggregate, a dihydrogypsum film is not formed on an aggregate for which adsorption of sulfur is not confirmed in the "judgment test of the aggregate that forms a dihydrate gypsum film". It can be said.

Claims (3)

A mortar containing a blast furnace slag fine aggregate (A), water (W), and a binder (D) containing blast furnace slag fine powder (B) and Portland cement (C), and used in an environment exposed to sulfuric acid A molded article formed by molding a concrete composition, wherein the blast furnace slag fine aggregate (A) is amorphous, and the specific surface area of the blast furnace slag fine powder (B) is 2500 to 6500 cm ² / g in terms of a brain value. And the mass ratio (C / D) of the Portland cement (C) to the binder (D) is 0.3 to 0.9, and the mass of the blast furnace slag fine powder (B) to the binder (D) Ratio (B / D) is 0.1-0.7, 100-1000 mass parts of blast furnace slag fine aggregate (A) is included with respect to 100 mass parts of binder (D), and binder (D) 100 25 to 42 parts by mass of water (W) with respect to parts by mass,
Portland cement (C) is ordinary Portland cement,
After the mortar or concrete specimen according to the mortar or concrete composition was cured in water for 7 days and then immersed in a sulfuric acid solution having a mass percent concentration of 5% for 56 days, the mass change rate was cured for 7 days in water. Exceeding 100% based on the mass of
The mass change rate exceeds 100% regardless of the water binder ratio (W / D), which is the mass ratio of water (W) to the binder (D), that is, the compressive strength of the mortar or concrete specimen. Yes,
The mortar or concrete specimens state, and are not dense dihydrate gypsum layer on the surface by contacting the sulfuric acid is formed,
A molded product obtained by molding the mortar or concrete composition, which is obtained by steam curing the mortar or concrete composition .   The molded article according to claim 1, which is used as a sewer pipe.   The molded article according to claim 1, wherein the molded article is used as an offshore structure.