Hydraulic composition, hydraulic composition mixed material, and hardened body

Abstract

The present invention provides a hydraulic composition which is capable of stably holding and storing CO2 collected from the atmosphere as well as reducing a cost. The present invention is a hydraulic composition containing calcium carbonate. A content of the calcium carbonate contained in materials is in a range of 30 percent by mass to 95 percent by mass. Further, the hydraulic composition contains at least one selected from blast furnace slag, an expansive additive, slaked lime, quick lime, fly ash and Portland cement. Note that, in a case of containing Portland cement, a content of the Portland cement in materials except for the calcium carbonate is 30 percent by mass and below. Furthermore, in a case of containing an expansive additive, a content of the expansive additive in materials is 2 to 9 percent by mass and below. [Fig. 1]

Description

Hydraulic composition, hydraulic composition mixed material, and cured product

[0001] The present invention relates to a hydraulic composition containing calcium carbonate, a hydraulic composition mixture containing the hydraulic composition, and a hardened body formed from the hydraulic composition or the hydraulic composition mixture.

[0002] When constructing construction components, CO ２ Calcium carbonate is sometimes added to concrete, mortar, and cement paste for the purpose of reducing carbon dioxide emissions and improving fire resistance. For example, Patent Document 1 discloses a cement-based material containing cement, calcium carbonate, aggregate, additives, and a porous material. ２ A technology has been developed to recover CO2 from the atmosphere and exhaust gases to produce calcium carbonate. ２ If calcium carbonate is contained in the hydraulic composition, CO ２ Fix or store CO ２ Furthermore, calcium carbonate undergoes an endothermic reaction at high temperatures, absorbing the surrounding heat and exhibiting self-extinguishing properties. Therefore, building materials that use calcium carbonate are fire-resistant.

[0003] Japanese Patent Application Laid-Open No. 2020-051117

[0004] The present invention is a method for recovering CO from the atmosphere. ２ The present invention aims to propose a hydraulic composition that can be stably maintained and stored and that can reduce costs, a hydraulic composition mixed material containing the hydraulic composition, and a hardened body formed from the hydraulic composition or the hydraulic composition mixed material.

[0005] The present invention relates to a hydraulic composition containing calcium carbonate, a hydraulic composition mixture containing the hydraulic composition, and a hardened body formed from the hydraulic composition or the hydraulic composition mixture. The content of the calcium carbonate in the hydraulic composition is within the range of 30% to 95% by mass, preferably 40% to 95% by mass, and more preferably 60% to 95% by mass. The hydraulic composition preferably contains, in addition to calcium carbonate, at least one material selected from blast furnace slag, an expanding agent, slaked lime, quicklime, fly ash, and Portland cement. It is particularly preferable for the hydraulic composition to contain blast furnace slag, slaked lime, and an expanding agent. When Portland cement is contained, the content of the Portland cement in the materials other than calcium carbonate is 70% by mass or less, more preferably 30% by mass or less. The expanding agent is preferably present in a proportion of 2 to 9% by mass relative to the total materials of the hydraulic composition. Such a hydraulic composition exhibits good fluidity before hardening, develops the required strength after hardening, and reduces CO₂ emissions by reducing the amount of cement used. ２ CO emissions reduction and use of calcium carbonate ２ Furthermore, since the hydraulic composition contains a large amount of industrial by-products such as blast furnace slag and fly ash, it contributes to the effective use of resources, and since it contains a large amount of calcium carbonate, it is possible to manufacture components with excellent fire resistance. ２ In addition to retaining CO, a neutralization reaction occurs during the service life of the facility, ２ It becomes possible to capture.

[0006] When the hydraulic composition of the present invention is used to construct a reinforced concrete structure, if the carbonation reaction occurs more than necessary during the service life, the rust prevention effect of reinforcing materials such as steel bars inside the concrete may be impaired. In such a case, it is recommended to use nitrate ions (NO ) based on 100% by mass of the hydraulic composition. ３－It is preferable that the hydraulic composition mixture of the present invention contains a nitrate chloride compound in a proportion of 1 to 3 mass % calculated as a formula weight (62). The hydraulic composition mixture of the present invention may contain the hydraulic composition and at least one material selected from a fibrous material, an aggregate, and a chemical admixture. When water is added to and mixed with the hydraulic composition or the hydraulic composition mixture, and a predetermined curing period has elapsed, a hardened body formed from the hydraulic composition or the hydraulic composition mixture is obtained.

[0007] According to the hydraulic composition, hydraulic composition mixture, and hardened product of the present invention, by adding a large amount of calcium carbonate, ２ Reduction of emissions and CO ２ This allows for stable maintenance and storage of the material, and also reduces costs.

[0008]

[0023] Fig. 1 is a graph showing the relationship between the proportion of calcium carbonate and the carbonation rate, which is the result of an experiment conducted on a hydraulic composition.

[0024] Fig. 1 is a graph showing the relationship between the strength and unit cement amount of a hardened body of a hydraulic composition mixture containing a hydraulic composition at 28 days.

[0025] Fig. 1 is a graph showing the relationship between the proportion of calcium carbonate in the hydraulic composition and the compressive strength of a hardened body of a hydraulic composition mixture containing the hydraulic composition at 28 days.

[0026] Fig. 1 is a graph showing the relationship between the proportion of Portland cement in the powder other than calcium carbonate in the hydraulic composition and the compressive strength ratio when the proportion of Portland cement in the powder other than calcium carbonate is 100%.

[0027] Fig. 1 is a graph showing the relationship between the number of days elapsed since the start of setting and shrinkage strain when the amount of expansive agent added to a hydraulic composition mixture is changed.

[0028] Fig. 1 is a graph showing the relationship between the number of days elapsed since the start of setting and shrinkage strain when the amount of expansive agent added to a hydraulic composition mixture is changed.

[0029] Fig. 2 is a graph showing the relationship between color difference and accelerated time, which is the result of an accelerated weathering test conducted on a hardened body.

[0009] In this embodiment, CO ２ Reduction of emissions and CO ２ To ensure stable storage and retention of CO from the atmosphere, ２The hydraulic composition of this embodiment is a mixture of calcium carbonate (CaCO ３ ), and at least one of blast furnace slag, expansive additive, slaked lime, quicklime, fly ash, and Portland cement. The hydraulic composition mixture of this embodiment contains, in addition to the hydraulic composition, aggregates such as sand and gravel, chemicals such as chemical admixtures for concrete, and fiber materials made of metals or polymeric materials. The hardened product of the hydraulic composition is obtained by hardening a paste obtained by kneading water with the hydraulic composition. The hardened product of the hydraulic composition mixture is obtained by hardening a mixture (equivalent to fresh mortar or fresh concrete) obtained by kneading water with the hydraulic composition mixture, and corresponds to mortar or concrete.

[0010] Calcium carbonate (CaCO ３ ) in the powder (the ratio of calcium carbonate (CaCO ３ The proportion of calcium carbonate (CaCO ) is in the range of 30% by mass to 95% by mass, preferably 40% by mass to 95% by mass, and more preferably 60% by mass to 95% by mass. ３ ), for example, ground calcium carbonate (CaCO ３ Natural calcium carbonate, known as precipitated calcium carbonate, and synthetic calcium carbonate, known as precipitated calcium carbonate, which is produced by a chemical reaction to precipitate fine crystals, can be used. ２ Calcium carbonate produced by recovering calcium and CO ２ Since it is synthesized by the reaction, it can be treated as light calcium carbonate.

[0011] It is desirable to use ground granulated blast furnace slag used in JIS (Japanese Industrial Standards) R5211 "blast furnace cement" or ground granulated blast furnace slag conforming to JIS A6206 "blast furnace slag for concrete." In addition, the blast furnace slag should have a specific surface area of ​​2000 to 10000 cm. ２ / g, preferably 3500 to 7000 cm ２It is desirable to use one with a viscosity of 1 / g. For example, an expansive additive specified in JIS A6202 "Expansive Additives for Concrete" may be used. It is desirable to add the expansive additive at a ratio of 2 to 9 mass% based on the total hydraulic composition. For example, slaked lime may be used that specified in JIS R9001 "Industrial Lime." Furthermore, since quicklime becomes slaked lime when it comes into contact with water, quicklime specified in JIS R9001 "Industrial Lime" can be used instead of slaked lime. In this case, it is advisable to adjust the amount of water required to convert quicklime to slaked lime. For example, fly ash conforming to JIS A6201 "Fly Ash for Concrete" may be used. Ordinary Portland cement is used as the Portland cement, but other types of Portland cement such as moderate-heat Portland cement, low-heat Portland cement, high-early-strength Portland cement, ultra-high-early-strength Portland cement, and sulfate-resistant Portland cement, as specified in JIS R5210 "Portland cement," and JIS R5214 "Ecocement" can also be used.

[0012] When the hydraulic composition contains Portland cement, calcium carbonate (CaCO ３ The proportion of Portland cement in the powder other than the above-mentioned components is set to 70% by mass or less, and preferably 30% by mass or less. When Portland cement and blast furnace slag or fly ash are used, the components may be pre-mixed, for example, as specified in JIS R5211 "blast furnace cement" or as specified in JIS R5213 "fly ash cement," and the pre-mixed components may be used alone or in combination.

[0013] The hydraulic composition of this embodiment exhibits the necessary strength after hardening. Furthermore, the hydraulic composition of this embodiment reduces the amount of cement used or omits Portland cement, thereby reducing CO2 emissions associated with the production of Portland cement. ２ Reduction of emissions and capture and fixation of CO from the atmosphere and exhaust gases ２The present invention provides a highly environmentally friendly hydraulic composition containing blast furnace slag and at least one of an expansive material, slaked lime, quicklime, fly ash, and Portland cement, and a calcium carbonate (CaCO ３ The hydraulic composition of this embodiment, which contains ordinary Portland cement and calcium carbonate (CaCO ３ Compared with hydraulic compositions containing calcium carbonate (CaCO ３ Even if the ratio of calcium carbonate (CaCO ) is increased, the decrease in strength can be suppressed. Furthermore, a blend containing a large amount of blast furnace slag can further suppress the decrease in strength. Furthermore, the hydraulic composition of this embodiment contains calcium carbonate (CaCO ３ ), it is possible to manufacture components with excellent fire resistance. ３ ) is CaCO at high temperatures (500-900°C). ３ →CaO+CO ２ Since the endothermic reaction occurs, the hydraulic composition of this embodiment has self-extinguishing properties in the event of a fire.

[0014] The results of experiments carried out on the hydraulic composition of this embodiment will be described below. (1) Carbonation Rate First, the ratio of calcium carbonate (CaCO 3 ) in the hydraulic composition was ３ ) was mixed in a ratio of 0 to 50 mass % with other materials in the ratios shown in Table 1 (cases a to j), and the hardened bodies of the hydraulic compositions were subjected to CO ２ The rate at which CO is absorbed (i.e., the neutralization rate) is ２ The measurement was carried out under accelerated conditions with a concentration of 5%. As shown in Table 1, cases a to c show that the calcium carbonate (CaCO ３ In case d, only Portland cement and blast furnace slag were used as powder materials, and in case e, calcium carbonate (CaCO ) was used as a powder material constituting the hydraulic composition. ３ In case f, the powder materials contained Portland cement, blast furnace slag, and fly ash. In cases d and f, calcium carbonate (CaCO３ In case g, calcium carbonate (CaCO ) is used as a powder material to reduce the environmental impact. ３ ), Portland cement, blast furnace slag, and fly ash were added. Furthermore, in cases h to j, calcium carbonate (CaCO ３ As a powder material other than the above, only Portland cement was added in the range of 50 to 100 mass %. Here, the ratio of calcium carbonate (CaCO ３ Cases a, b, d, f, h, and i in which the amount of ) is less than 30 mass % are comparative examples, and cases c, e, g, and j in which the amount is 30 mass % or more are examples.

[0015] The following materials were used in the experiment: Water: tap water Calcium carbonate (CaCO ３ ): Light calcium carbonate, density 2.67 g / cm 3 , BET specific surface area 5.0m 2 / g Portland cement: Ordinary Portland cement Density 3.16 g / cm 3 , Blaine specific surface area 3270 cm 2 / g, JIS R5210 Blast furnace slag: Blast furnace slag powder 4000, density 2.89 g / cm 3 , Blaine specific surface area 4480 cm 2 / g, JIS A6206 Expansion agent: Expansion agent type 30 (lime-based expansion agent) Density 3.15 g / cm 3 , Blaine specific surface area 3810 cm 2 / g, JIS A6202 slaked lime: special slaked lime, density 2.20 g / cm 3 , 600 μm sieve complete, JIS R9001 Fly ash: Fly ash type II, density 2.30 g / cm 3 , Blaine specific surface area 4640 cm 2 / g, JIS A6201

[0016]

[0017] Water W was added to hydraulic composition P according to the formulation in Table 1 so that the water-powder ratio W / P was 0.50, and the mixture was kneaded. A test specimen approximately 3 cm in diameter and 5 cm in height was prepared from the resulting kneaded product (paste), which was then sealed and cured. The test specimen was demolded at 28 days old and stored for 7 days at a temperature of 20°C and a humidity of 60%. After that, all surfaces except for one bottom surface were coated with aluminum adhesive tape, and the specimen was stored at a temperature of 20°C, a humidity of 60%, and CO ２ An accelerated carbonation test was conducted by placing the specimens in an environment containing a 5% phenolphthalein concentration. After 14 or 28 days, the specimens were split open, and a 1% alcohol solution of phenolphthalein was sprayed onto the cross section. The area where no coloration occurred was considered to be the area where carbonation had progressed, and the accelerated carbonation depth was measured. The measurement results are shown in Table 2. It is known that carbonation progresses in proportion to the square root of the carbonation period, and when the relationship between the change in accelerated carbonation depth and the square root of the carbonation period is approximated by a straight line (linear approximation), the slope of the line can be taken as the carbonation rate. In other words, the carbonation rate represents the rate of change in carbonation depth relative to the change in the square root of the accelerated carbonation period. Figure 1 shows the carbonation rate of calcium carbonate (CaCO ３ ) and the rate of carbonation.

[0018]

[0019] As shown in Table 2 and Figure 1, in cases a to c, calcium carbonate (CaCO ３ The amount of calcium carbonate (CaCO) was increased to 8.6 mass%, 25 mass%, and 50 mass%, and the carbonation rates of these blends were 0.507, 0.646, and 0.861 cm / √d, respectively. ３ The results showed that the carbonation rate increased as the amount of calcium carbonate (CaCO ３ As the amount of calcium carbonate (CaCO ) increased, the carbonation rate also increased. ３ As the amount of calcium carbonate (CaCO ３The carbonation rate in case j tended to be faster with increasing amount of calcium carbonate (CaCO ３ ) was smaller than those of cases c, e, and g containing the same.

[0020] As shown in FIG. 1, calcium carbonate (CaCO ３ From the comparison of cases h, d, and f where calcium carbonate (CaCO ３ If the amount of Portland cement in the powder other than the hydraulic composition (powder) is reduced to 30 mass % or less, the carbonation rate can be increased. ３ When the amount of calcium carbonate (CaCO ３ Regardless of the blending of powders other than calcium carbonate (CaCO ３ It is expected that the neutralization rate will be equal to or greater than that of calcium carbonate (CaCO ３ When the amount of calcium carbonate (CaCO ) is 40% by mass or more, ３ Regardless of the blending of powders other than calcium carbonate (CaCO ３ It is expected that the carbonation rate will be equal to or higher than that of the formulation for reducing the environmental load without using calcium carbonate (CaCO ). ３ When the amount of calcium carbonate (CaCO) is 30% by mass or more, preferably 40% by mass or more, ３ Regardless of the composition of the powder other than the above, the same or better effect as when the proportion of Portland cement in the powder is reduced can be obtained. In this way, the hydraulic mixture with an increased carbonation rate can reduce the carbon dioxide in the atmosphere after hardening. ２ It is expected that the amount of CO2 in the atmosphere will be reduced during operation. ２ It was confirmed that an increase in the amount of fixation can be expected.

[0021] The proportion of calcium carbonate (CaCO ３When comparing cases c, g, e, and j in which the ratio of blast furnace slag in the hydraulic composition is equal, the ratio of calcium carbonate (CaCO ３ When the proportion of blast furnace slag in the powder other than calcium carbonate (CaCO ) increases, the neutralization rate tends to be faster. ３ The proportion of blast furnace slag in the powder other than calcium carbonate (CaCO ３ It is preferable to increase the size of the powder (blast furnace slag, Portland cement, expansive material, slaked lime, fly ash) other than calcium carbonate (CaCO ３ It is more preferable that the proportion of blast furnace slag in the powder other than the above-mentioned powder is 40 mass % or more.

[0022] (2) Compressive strength When a hydraulic composition is used as a structural member, it is desirable that the hydraulic composition has a compressive strength that can withstand the applied load. Therefore, for a hydraulic composition mixed material containing a hydraulic composition and fine aggregate (sand), the calcium carbonate (CaCO ) in the hydraulic composition was measured. ３ ) in the hydraulic composition, ３ The compressive strength after hardening (strength at 7 days and strength at 28 days) was measured when the type and amount of each material other than the concrete and the water-powder ratio were changed.

[0023] The following materials were used in the experiment: Water: tap water Portland cement: ordinary Portland cement, density 3.16 g / cm 3 , specific surface area 3270cm 2 / g, JIS R5210 Blast furnace slag: Blast furnace slag powder 4000, density 2.89 g / cm 3 , Blaine specific surface area 4480 cm 2 / g, JIS A6206 Expansion agent: Expansion agent type 30 (lime-based expansion agent) Density 3.15 g / cm 3 , Blaine specific surface area 3810 cm 2 / g, JIS A6202 slaked lime: special slaked lime density 2.20 g / cm 3 , 600 μm sieve complete, JIS R9001 Fly ash: Type II, density 2.30 g / cm3 , specific surface area 4640cm 2 / g, JIS A6201 Calcium carbonate (CaCO ３ ) : Light calcium carbonate Density 2.67g / cm 3 , BET specific surface area 5.0m 2 / g Fine aggregate: A mixture of mountain sand from Kimitsu, crushed sand from Tsukumi, and crushed sand from Watarai. Surface dry density: 2.60 g / cm 3 Water absorption rate 2.07%

[0024] Table 3 shows the blending ratio. Table 4 shows the strength test results. Table 4 also shows Cases 1 to 4 in which the hydraulic composition contains blast furnace slag, and Case 5 in which the hydraulic composition contains Portland cement and calcium carbonate (CaCO ３ ) and calcium carbonate (CaCO ３ The figures shown are the strength ratios (compressive strength ratio = Cases 1 to 4 / Cases A and B) when the proportion of calcium carbonate (CaCO ) in the hydraulic composition is the same. Here, the numbers "25", "50", etc. added after Cases 1 to 4 and Cases A and B indicate the proportion of calcium carbonate (CaCO ) in the hydraulic composition. ３ ) (mass %). Therefore, among Cases 1 to 4 and Cases A and B, those marked with the numbers "0," "25," and "99" are comparative examples, and the rest are working examples. In Table 4, for example, the compressive strength ratios listed in the Case 1-50 and Case 2-50 columns are ratios to the strength of Case A-50, and the compressive strength ratio listed in the Case 4-70 column is ratios to the strength of Case B-70. In addition, the compressive strength ratios listed in the Case 1-25 and Case 2-25 columns are ratios to the strength of Case A-25.

[0025]

[0026]

[0027] Figure 2 shows the unit cement content (kg / m 3In case A, the W / P ratio was standardized to 0.5, and the results of the hardened product (mortar) of the kneaded material with a W / P of 0.5 were shown. In case B, calcium carbonate (CaCO ３ In the case where all powder materials except for the above were Portland cement, calcium carbonate (CaCO ３ On the other hand, in cases 1 to 3 (where the proportion of calcium carbonate (CaCO ) in the powder materials constituting the hydraulic composition was high and the amount of Portland cement used (unit cement amount) was low), the strength decreased. ３ In the case of the powder material other than the Portland cement (Case A), the compressive strength was significantly higher than that of Case A, even with a small unit cement content. ３ A hydraulic composition containing the above-mentioned hydroxyl group has sufficient strength for practical use even when the amount of Portland cement used is significantly reduced.

[0028] In FIG. 2, dotted lines A to D represent the proportion of calcium carbonate (CaCO ) in the hydraulic composition. ３ ) is an approximate line connecting the strengths of mixtures with the same proportions. ３ In the case of dotted line A (comparison example) where the proportion of calcium carbonate (CaCO ) in the hydraulic composition is 25 mass %, the strength decreases as the unit cement amount decreases, and no improvement in strength is obtained even when the materials used and proportions of the hydraulic composition are adjusted. ３ In the dotted lines B to D (Examples) where the proportion of calcium carbonate (CaCO ) in the hydraulic composition is 50 to 90 mass %, it can be seen that the strength increases as the unit cement amount decreases. That is, the hydraulic composition and hydraulic composition mixture according to this embodiment have a high strength when the proportion of calcium carbonate (CaCO ) in the hydraulic composition is 50 to 90 mass %. ３ The higher the proportion of ) the greater the effect of reducing the amount of cement per unit without weakening the compressive strength.

[0029] In addition, the straight lines i to iv in FIG. 2 represent the calcium carbonate (CaCO ３The approximate line is drawn for the change in strength of a mixture in which the proportion of Portland cement in the powder excluding calcium carbonate (CaCO ) is equal. ３ The line i represents the measurement points where the proportion of calcium carbonate (CaCO ３ 2), the proportion of Portland cement in the powder excluding calcium carbonate (CaCO ) is 100% by mass, and lines ii, iii, and iv represent the cases of 30%, 15%, and 0% by mass, respectively. As can be seen from lines i to iii in Figure 2, ３ The smaller the proportion of Portland cement in the powder excluding calcium carbonate (CaCO ), the greater the rate of increase in strength per unit cement content. ３ By using blast furnace slag, expansive agent, hydrated lime, and fly ash as powders other than the above and reducing the proportion of Portland cement, it is possible to achieve the significant effect of increasing compressive strength without significantly increasing the unit cement amount.

[0030] Figure 3 is a graph of the compressive strength ratio at 28 days (28d) shown in Table 4. As shown in Figures 2 and 3 and Table 4, calcium carbonate (CaCO ３ When the proportion of calcium carbonate (CaCO ) is 25 mass% (cases 1-25, 2-25, 3-25, and 4-25), ３ ) and Portland cement only, the compressive strength was lower than that of Cases A-25 and B-25. ３ When the ratio of calcium carbonate (CaCO ) is 50 mass% or more (cases 1-50, 1-70, 1-90, 2-50, 2-70, 2-90, 3-70, and 4-70), ３ It was confirmed that the compressive strength was higher than that of cases A-50, A-70, A-90, B-50, and B-70, which were made with only calcium carbonate (CaCO ３ ) exceeds 25 mass%, the compressive strength ratio may exceed 1. From the graph of FIG. 3, it can be seen that ３It can be seen that when the proportion of calcium carbonate (CaCO ) in the hydraulic composition exceeds 30 mass %, the compressive strength ratio exceeds 1. ３ When the proportion of calcium carbonate (CaCO ) is 30% by mass or more, even when Portland cement is replaced with a material using blast furnace slag and at least one of an expanding agent, slaked lime, quicklime, fly ash, and Portland cement, the content of calcium carbonate (CaCO ) is 30% by mass or more. ３ The strength of the hydraulic composition can be equal to or greater than that of a mixed material of only calcium carbonate (CaCO ) and Portland cement. ３ When the proportion of ) is 40% by mass or more, the compressive strength ratio generally exceeds 1.2, which is preferable, and when it is 60% by mass or more, the compressive strength ratio generally exceeds 1.4, which is more preferable.

[0031] Figure 4 shows the ratio of the slopes of lines ii to iv shown in Figure 2 to line i. Since the slopes of lines i to iv indicate the compressive strength per unit cement content, the ratio of the slopes of lines ii to iv to line i can be considered as the ratio of compressive strengths for the same unit cement content, and this is shown on the vertical axis as the compressive strength ratio. Calcium carbonate (CaCO ３ When the proportion of Portland cement in the powder other than calcium carbonate (CaCO ) is reduced, the compressive strength ratio increases, and the effect of the present invention can be confirmed. ３ When the proportion of Portland cement in the powder other than calcium carbonate (CaCO ) is 70% by mass or less, the compressive strength ratio exceeds 2, and when it is 30% by mass or less, the compressive strength ratio generally exceeds 4. ３ The proportion of Portland cement in the powder other than the above is preferably 70% by mass or less, more preferably 30% by mass or less.

[0032] In addition, calcium carbonate (CaCO ３ As can be seen from the results of Cases 1-50, 1-70, 1-90 and 2-50, 2-70, 2-90, in which the proportion of Portland cement in the powder other than calcium carbonate (CaCO ) was 30 mass% or less, the compressive strength tends to increase as the proportion of blast furnace slag increases.３ When the proportion of Portland cement in the powder other than calcium carbonate (CaCO ３ The proportion of blast furnace slag in the powder other than the above is preferably 70 mass % or more, and more preferably 80 mass % or more.

[0033] (3) Calcium carbonate (CaCO ３ Next, for a hydraulic composition mixed material containing the hydraulic composition of this embodiment, fine aggregate (sand) and coarse aggregate (gravel), the ratio of calcium carbonate (CaCO ) in the hydraulic composition was changed between 42 and 70%. ３ The ratio of water to hydraulic composition was varied between 42 and 70%, and the properties were confirmed. Specifically, the slump or slump flow of a mixture of hydraulic composition and water (hereinafter sometimes referred to as "fresh concrete") and the compressive strength (strength at 1 day, 7 days, and 28 days) of the hardened product of the mixture (hereinafter sometimes referred to as "concrete") were measured. The test specimens (concrete) for compressive strength were demolded at 2 days of age and then subjected to standard underwater curing at 20°C. In addition, in Examples 33, 35, and 38, the specimens were subjected to sealed curing at 20°C for 2 hours, followed by steam curing at 60°C for 2.5 hours, and the compressive strength at 1 day of age was measured.

[0034] The following materials were used in the experiment: Water: tap water Blast furnace slag: 4000g ground blast furnace slag, density 2.89g / cm 3 , Blaine specific surface area 4480 cm 2 / g, JIS A6206 Expansion agent: Expansion agent type 30 (lime-based expansion agent) Density 3.15 g / cm 3 , Blaine specific surface area 3810 cm 2 / g, JIS A6202 slaked lime: special slaked lime density 2.20 g / cm 3 , 600 μm sieve complete, JIS R9001 calcium carbonate (CaCO ３ ): Light calcium carbonate, density 2.67 g / cm 3 , BET specific surface area 5m 2 / g Fine aggregate: A mixture of mountain sand from Kimitsu, crushed sand from Tsukumi, and crushed sand from Watarai. Surface dry density: 2.60 g / cm 3Water absorption rate: 2.07% Coarse aggregate: Ome crushed stone, maximum particle size: 20 mm, surface dry density: 2.66 g / cm 3 The composition of this experiment is shown in Table 5. The strength test results are shown in Table 6.

[0035]

[0036]

[0037] As shown in Table 6, the fresh concretes of Examples 31, 32, 33, 34, 36, and 37 all had slump flows exceeding 46.0 cm, demonstrating high fluidity. These fresh concretes did not experience material segregation and were suitable for use as high-fluidity concrete. Furthermore, the fresh concretes of Examples 35 and 38 had slumps of 13.5 cm and 20 cm, respectively. Thus, it is possible to produce ordinary fresh concrete that does not have high fluidity. JIS A 5308 specifies the ranges for slump and slump flow for ordinary concrete. According to JIS regulations, a slump of 5.5 to 22.5 cm or a slump flow of 37.5 to 70.0 cm is required, and all of the fresh concrete produced in this study met these standards.

[0038] In Examples 31 to 38, the compressive strength was 17 to 40 N / mm at the age of 7 days. ２ At 28 days old, the strength is 22 to 55 N / mm ２ Calcium carbonate (CaCO ３ Even when a large amount of 42 to 70% of the total powder of the hydraulic composition is added, the hardness is 20 N / mm ２ Furthermore, by setting the W / P ratio to 0.241 or less, a compressive strength of 40 N / mm ２ As described above, it was possible to produce high-strength concrete exceeding the calcium carbonate (CaCO ) content in the powder constituting the hydraulic composition. ３It was confirmed that when the proportion of slag) was 42 to 70 mass%, it was possible to produce fresh concrete with workability similar to that of general concrete used in structural members such as reinforced concrete, and that it was possible to produce concrete with compressive strength comparable to that of general concrete.

[0039] (4) Neutralization rate of hydraulic composition mixture containing nitrate compound or nitrite compound Calcium carbonate (CaCO ３ A hydraulic composition mixed material (hydraulic composition mixed material) containing 45% by mass of the hydraulic composition and nitrate compound, with the proportions shown in Table 7, and other materials being 45% by mass, was mixed with water to give a W / P ratio of 0.305 to prepare a paste of the hydraulic composition mixed material, which was then hardened. When the nitrate compound contains bound water, the amount of water to be added was determined by dividing the value of the bound water. The amount of the nitrate compound to be added was determined so that the amount of nitrogen atoms (N) was 0.45% by mass (nitrate ions (NO)) relative to 100% by mass of the hydraulic composition. ３ － The nitrate compound may be mixed with the hydraulic composition in a powder state, or may be dissolved in water and then mixed with the hydraulic composition. ２ ) ２ ・H ２ O, NaNO ２ is a nitrite compound, but in the present invention it is described as a nitrite compound and does not contain nitrite ions (NO ２ － ) is the nitrate ion (NO ３ － ) was converted.

[0040] The following materials were used in the experiment: Water: tap water Blast furnace slag: 4000g ground blast furnace slag, density 2.89g / cm 3 , Blaine specific surface area 4480 cm 2 / g, JIS A6206 Expansion agent: Expansion agent type 30 (lime-based expansion agent) Density 3.15 g / cm 3 , Blaine specific surface area 3810 cm 2 / g, JIS A6202 slaked lime: special slaked lime density 2.20 g / cm 3, 600 μm sieve complete, JIS R9001 calcium carbonate (CaCO ３ ): Light calcium carbonate, density 2.67 g / cm 3 , BET specific surface area 5.0m 2 / g Ca(NO ２ ) ２ ・H ２ O: Manufactured by Kanto Chemical Co., Ltd., conforming to Kanto Chemical Co., Ltd. Class 1 standard (purity 90.0% or more (titration method)) Ca(NO ３ ) ２ ・4H ２ O: Kanto Chemical Co., Ltd., JIS K8549 (purity 99.0% or more (difference method)) Mg(NO ３ ) ２ ・6H ２ O: NaNO manufactured by Kanto Chemical Co., Ltd., JIS K8567 (purity 99.0% or more (titration method)) ２ : Manufactured by Kanto Chemical Co., Ltd., JIS K8019 (purity 98.5% or more (titration method)) NaNO ３ : Manufactured by Kanto Chemical Co., Ltd., JIS K8542 (purity 99.0% or more (titration method)) KNO ３ : Kanto Chemical Co., Ltd., JIS K8548 (purity 99.0% or more (titration method)) NH ４ NO ３ : Kanto Chemical Co., Ltd., JIS K8545 (purity 99.0% or more (titration method))

[0041]

[0042] A test specimen measuring approximately 3 cm in diameter and 5 cm in height was prepared using a paste prepared by mixing a hydraulic composition mixture having the composition shown in Table 7 with a predetermined amount of water, and then sealed and cured. The specimen was demolded at 28 days old and stored at a temperature of 20°C and a humidity of 60% for 7 days after demolding. After that, all surfaces except for one bottom surface were coated with aluminum adhesive tape, and the specimen was stored at a temperature of 20°C, a humidity of 60%, and CO ２An accelerated carbonation test was conducted by placing the specimen in an environment containing 5% phenolphthalein. After a predetermined period of time had passed, the specimen was split open, and a 1% alcohol solution of phenolphthalein was sprayed onto the cross section. The area where no coloration occurred was considered to be the area where carbonation had progressed, and the accelerated carbonation depth was measured. The measurement results are shown in Table 8. It is known that carbonation progresses in proportion to the square root of the carbonation period. When the relationship between the change in accelerated carbonation depth and the square root of the carbonation period is approximated by a straight line (linear approximation), the slope of the line can be taken as the carbonation rate. In other words, the carbonation rate indicates the rate of change in carbonation depth relative to the change in the square root of the accelerated carbonation period.

[0043]

[0044] As shown in Table 8, calcium nitrite monohydrate (Ca(NO ２ ) ２ ・H ２ O), calcium nitrate tetrahydrate (Ca(NO ３ ) ２ ・4H ２ O), magnesium nitrate hexahydrate (Mg(NO ３ ) ２ ・6H ２ When calcium nitrite, calcium nitrate, and magnesium nitrate were added, a significant carbonation suppression effect was observed, and the carbonation rate was reduced to 60% or less compared to when no nitrate was added. Therefore, it was confirmed that the carbonation rate of the hardened body of the hydraulic composition mixture can be suppressed by adding calcium nitrite, calcium nitrate, and magnesium nitrate.

[0045] (5) Carbonation rate of hydraulic composition mixture containing chemical admixture Calcium carbonate (CaCO ３ A mixture of hydraulic composition and chemical admixture (hydraulic composition mixture) containing 45% by mass of the hydroxybenzoate and 45% by weight of the other materials in the proportions shown in Table 9 was mixed with water to give a W / P ratio of 0.305 to prepare a paste of hydraulic composition mixture, which was then allowed to harden. The obtained hardened product was subjected to an accelerated carbonation test, and the carbonation rate was calculated. The measurement results are shown in Table 10.

[0046] The following materials were used in this experiment: Water: tap water Blast furnace slag: 4000g ground blast furnace slag, density 2.89g / cm3 , Blaine specific surface area 4480 cm 2 / g, JIS A6206 Expansion agent: Expansion agent type 30 (lime-based expansion agent) Density 3.15 g / cm 3 , Blaine specific surface area 3810 cm 2 / g, JIS A6202 slaked lime: special slaked lime density 2.20 g / cm 3 , 600 μm sieve complete, JIS R9001 calcium carbonate (CaCO ３ ): Light calcium carbonate, density 2.67 g / cm 3 , BET specific surface area 5.0m 2 / g Chemical admixture: Masterset FZP99, manufactured by Pozzolith Solutions, nitrate ion equivalent content 24 mass%

[0047]

[0048] A test specimen measuring approximately 3 cm in diameter and 5 cm in height was prepared using a paste prepared by mixing a hydraulic composition mixture having the composition shown in Table 9 with a predetermined amount of water, and then sealed and cured. The specimen was demolded at 28 days old and stored at a temperature of 20°C and a humidity of 60% for 7 days after demolding. After that, all surfaces except for one bottom surface were coated with aluminum adhesive tape, and the specimen was stored at a temperature of 20°C, a humidity of 60%, and CO ２ An accelerated carbonation test was conducted by placing the specimen in an environment containing 5% phenolphthalein. After a predetermined period of time had passed, the specimen was split open, and a 1% alcohol solution of phenolphthalein was sprayed onto the cross section. The area where no coloration occurred was considered to be the area where carbonation had progressed, and the accelerated carbonation depth was measured. The measurement results are shown in Table 10. It is known that carbonation progresses in proportion to the square root of the carbonation period. When the relationship between the change in accelerated carbonation depth and the square root of the carbonation period is approximated by a straight line (linear approximation), the slope of the line can be taken as the carbonation rate. In other words, the carbonation rate represents the rate of change in carbonation depth relative to the change in the square root of the accelerated carbonation period.

[0049]

[0050] As shown in Table 10, nitrate ions (NO ３ － ) is added in an amount of 6 mass % or more (NO) relative to 100 mass % of the hydraulic composition. ３－ When nitrate was added in an amount of 1% by mass or more, calculated as nitrate ions, a significant carbonation suppression effect was observed, with the carbonation rate being halved compared to when no nitrate was added. Furthermore, the carbonation rate decreased as the amount of chemical admixture increased. Therefore, it was confirmed that the carbonation rate of the hardened body of the hydraulic composition mixture can be suppressed by adding 1% by mass or more of nitrate, calculated as nitrate ions, to 100% by mass of the hydraulic composition.

[0051] (6) Properties with Varying the Amount of Expansive Additive Next, the properties of hydraulic compositions containing expansive additives were examined. The proportion of expansive additive in the hydraulic composition (powder) was varied between 2 and 9% by mass. In this experiment, a hydraulic composition mixture containing a hydraulic composition, fine aggregate (sand), and coarse aggregate (gravel) was mixed with water. The resulting mixture (hereinafter sometimes referred to as "fresh concrete") was measured for slump or slump flow, and the initial and final setting times. Furthermore, the hardened mixture (hereinafter sometimes referred to as "concrete") was measured for compressive strength (strength at 28 days) and autogenous shrinkage strain. The initial and final setting times were measured in accordance with JIS A 1147:2019, Test Method for Setting Time of Concrete.

[0052] The autogenous shrinkage strain was measured in accordance with the autogenous shrinkage test method for high-flow concrete described in Report II of the Super-Fluidity Concrete Research Committee of the Japan Concrete Institute (JCI). Specifically, an embedded strain gauge was installed in the center of a 10 cm x 10 cm x 40 cm concrete prism specimen. After pouring, the specimen was demolded two days later and sealed with vinyl in a room at 20°C. The shrinkage was measured up to 30 days later, and this measurement was used as the autogenous shrinkage strain. Table 11 shows the mix proportions for this experiment. Table 12 and Figures 5 and 6 show the results of the compressive strength test.

[0053] The following materials were used in the experiment: Water: tap water Blast furnace slag: 4000g ground blast furnace slag, density 2.89g / cm 3 , Blaine specific surface area 4480 cm 2 / g, JIS A6206 Expansion agent: Expansion agent type 30 (lime-based expansion agent) Density 3.15 g / cm 3 , Blaine specific surface area 3810 cm 2 / g, JIS A6202 slaked lime: special slaked lime density 2.20 g / cm 3 , 600 μm sieve complete, JIS R9001 calcium carbonate (CaCO ３ ): Light calcium carbonate, density 2.6 g / cm 3 , BET specific surface area 5.0m 2 / g Fine aggregate: Mixture of mountain sand from Kimitsu, crushed sand from Tsukumi, and crushed sand from Watarai Surface dry density 2.60 g / cm 3 Water absorption rate: 2.07% Coarse aggregate: Ome crushed stone, maximum particle size: 20 mm, surface dry density: 2.66 g / cm 3 Water absorption rate 0.60%

[0054]

[0055]

[0056] As shown in Table 12, in all examples, the slump was 19 cm or the slump flow was 40.0 to 60.0 cm, which is within the range of 6.5 to 22.5 cm or 37.5 to 70.0 cm for ordinary concrete as defined in JIS A 5308, demonstrating appropriate fluidity. In addition, the compressive strength at 28 days was 30 N / mm ２ That is, the hydraulic composition mixtures of Examples 61 to 66 had sufficient compressive strength, with the proportion of the expansive material in the hydraulic composition being 2 to 9 mass % (the amount of expansive material used being 14 to 57 kg / m 3 ), the concrete still had properties that allowed it to be manufactured and constructed.

[0057] As shown in Table 12 and FIG. 5, in Examples 61 and 62, the autogenous shrinkage strain was −442×10 －６ , −417×10 －６ On the other hand, when the proportion of the expansive material in the hydraulic composition was 6 mass % or 9 mass % (the amount of expansive material used was 41 kg / m 3 or 57 kg / m 3In Examples 63 and 64, the autogenous shrinkage strain was -347 × 10 －６ , −0.16×10 －６ Even in Examples 65 and 66, which have a larger unit water content than Examples 61 to 64, the autogenous shrinkage strain was reduced by increasing the proportion of expansive additive (see Figure 6). ３ It was confirmed that when the proportion of expansive agent was changed from 2 to 9 mass% in a mix in which the proportion of expansive agent was 40 to 52 mass%, concrete could be manufactured using the same method as ordinary concrete, and that the autogenous shrinkage strain could be controlled by adding expansive agent.

[0058] (7) Properties when fibrous material is added Next, the properties of the hardened product (hereinafter sometimes referred to as "concrete") of the hydraulic composition mixed material containing the hydraulic composition of this embodiment, the fibrous material, the fine aggregate, and the coarse aggregate were confirmed. Specifically, the slump or slump flow of the mixture of the hydraulic composition mixed material and water (hereinafter sometimes referred to as "fresh concrete") and the compressive strength (strength at 1 day, 2 days, and 28 days) of the hardened product of the mixture were measured.

[0059] The following materials were used in the experiment: Water: tap water Blast furnace slag: 4000g ground blast furnace slag, density 2.89g / cm 3 , Blaine specific surface area 4480 cm 2 / g, JIS A6206 Expansion agent: Expansion agent type 30 (lime-based expansion agent) Density 3.15 g / cm 3 , Blaine specific surface area 3810 cm 2 / g, JIS A6202 slaked lime: special slaked lime density 2.20 g / cm 3 , 600 μm sieve complete, JIS R9001 calcium carbonate (CaCO ３ ): Light calcium carbonate, density 2.67 g / cm 3 , Blaine specific surface area 4350 cm 2 / g Fine aggregate: A mixture of Namegata land sand and Sano limestone crushed sand. Surface dry density: 2.64 g / cm 3Water absorption rate: 1.91% Coarse aggregate: Sano limestone crushed stone, maximum particle size: 20 mm, surface dry density: 2.71 g / cm 3 Water absorption: 0.97% Fiber material: steel fiber, 35 mm long (Dramix3D, manufactured by Bekaert Japan) Chemical admixture: Masterset FZP99, manufactured by Pozzolith Solutions, nitrate ion equivalent content: 24% by mass Table 13 shows the formulation of this experiment. Table 14 shows the strength test results.

[0060]

[0061]

[0062] As shown in Table 14, in Examples 71, 72, 73, and 74, the slump flow of the fresh concrete (hydraulic composition mixed material after the addition of steel fiber) exceeded 50.0 cm, demonstrating high fluidity. No material separation of the steel fiber or aggregate occurred, and fresh concrete that was suitable for workability was produced. JIS A 5308 specifies the range of slump flow for ordinary concrete, requiring a slump flow of 37.5 to 70.0 cm. All of the fresh concrete produced in this study after the addition of steel fiber met this standard.

[0063] In Examples 71, 72, 73, and 74, the compressive strength was 5 to 10 N / mm at the time of one day of age. ２ The compressive strength at the age of 2 days is 14 to 23 N / mm ２ In addition, the compressive strength at the age of 28 days was 40 to 58 N / mm ２ Calcium carbonate (CaCO ３ ) does not have hydration activity, but calcium carbonate (CaCO ３ Even if the ratio of ) is as large as 46.4 mass%, it is 40 N / mm ２ The compressive strength of the above mentioned value could be ensured. Furthermore, by adding steel fibers, it is expected that the compressive strength will be increased in addition to the bending strength. For example, Example 72 is substantially the same as Example 66 (see Table 11) to which steel fibers have been added, but when comparing the compressive strength at 28 days, Example 66 to which no steel fibers have been added has a compressive strength of 34 N / mm ２In contrast, Example 72, in which steel fibers were added, had a strength of 43 N / mm ２ From the above results, it can be seen that the proportion of calcium carbonate (CaCO ３ It was confirmed that it is possible to produce concrete with workability and compressive strength equivalent to that of ordinary fiber-reinforced concrete, even when the proportion of fiber reinforced concrete is increased and a hydraulic composition mixture containing added fiber material is used.

[0064] (8) Effect of Polishing Next, the effect of polishing the surface of the hardened hydraulic composition mixed material containing the hydraulic composition of this embodiment, fine aggregate, and coarse aggregate was confirmed. In the following hydraulic composition mixed material, calcium carbonate (CaCO 3 ) in the hydraulic composition was ３ The ratio of sintered concrete to the hydraulic composition mixture (hydraulic composition, fine aggregate, and coarse aggregate) was 41.3% by mass. Water was then added to the hydraulic composition mixture (hydraulic composition, fine aggregate, and coarse aggregate) and the mixture (fresh concrete) was poured into a formwork and allowed to harden, producing rectangular specimens measuring 15 cm x 15 cm x 1 cm thick. The specimens were sealed and cured outdoors (at an ambient temperature of 0-7°C) for up to 14 days, then demolded and polished with a stone polishing machine to a grit size of #400. Table 15 shows the composition.

[0065] The following materials were used in the experiment: Water: tap water Blast furnace slag: 4000g ground blast furnace slag, density 2.89g / cm 3 , Blaine specific surface area 4480 cm 2 / g, JIS A6206 Expansion agent: Expansion agent type 30 (lime-based expansion agent) Density 3.15 g / cm 3 , Blaine specific surface area 3810 cm 2 / g, JIS A6202 slaked lime: special slaked lime density 2.20 g / cm 3 , 600 μm sieve complete, JIS R9001 calcium carbonate (CaCO ３ ): Light calcium carbonate, density 2.67 g / cm 3 , BET specific surface area 5.0m 2 / g Fine aggregate: Granite crushed sand from Inada, surface dry density 2.60 g / cm 3Water absorption rate: 0.38% Coarse aggregate: Granite crushed stone from Inada, maximum particle size: 12 mm, surface dry density: 2.62 g / cm 3 Water absorption rate 0.64%

[0066]

[0067] The test specimens (hardened bodies of hydraulic composition mixtures) were stored indoors at a temperature of 20°C, and after 28 days, they were subjected to an accelerated weathering test using an XER-W75 (manufactured by Iwasaki Electric) with a dry-wet cycle of 2 hours (dry 102 minutes, wet 18 minutes) and an irradiation intensity of 60 W / m ２ The accelerated test was carried out for 5000 hours under the conditions of 0, 500, 1000, 2000, 3000, 4000, and 5000 hours. The L of 24 hardened parts (non-aggregate parts) of the test specimen was measured using a spectrophotometer (NF333: manufactured by Nippon Denshoku Industries Co., Ltd.). ＊ a ＊ b ＊ The color space (JIS Z8781-4) was measured, the average value was calculated, and the color difference with the specimen at time 0 was evaluated. Figure 7 shows the relationship between the acceleration time and the color difference.

[0068] The prepared specimen was polished to a smooth finish, with no chipped or other defects in the aggregate, making it possible to create a finished material that resembled marble or other stone materials. As shown in Figure 7, no color change was observed even after 5,000 hours, confirming that the specimen was not subject to discoloration due to ultraviolet rays. Furthermore, a cylindrical specimen, 10 cm in diameter and 20 cm in height, was prepared separately, sealed and cured, and tested for compressive strength after 28 days. The compressive strength was 36.2 N / mm. ２ Calcium carbonate (CaCO ３ By polishing the hardened hydraulic composition mixture containing a large amount of ammonium nitrate, it was possible to create a finished material that resembled stone. Furthermore, weather resistance tests confirmed that the hardened material did not discolor.

[0069] Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and the above-described components can be appropriately changed without departing from the spirit of the present invention. For example, calcium carbonate (CaCO ３The materials constituting the blast furnace slag, expansive material, slaked lime, quicklime, fly ash and Portland cement are not limited to those shown in the above embodiment.

Claims

1. A hydraulic composition containing calcium carbonate, characterized in that the proportion of said calcium carbonate is within the range of 30% by mass to 95% by mass.

2. The hydraulic composition according to claim 1, characterized in that it contains blast furnace slag.

3. The hydraulic composition according to claim 2, comprising hydrated lime and an expansive material.

4. A hydraulic composition according to any one of claims 1 to 3, characterized in that it contains an expansive material in an amount of 2 to 9 mass %.

5. The hydraulic composition according to claim 1, characterized in that it contains at least one of blast furnace slag, expansive material, hydrated lime, quicklime, fly ash, and Portland cement.

6. A hydraulic composition according to any one of claims 1 to 5, characterized in that the materials other than calcium carbonate contain Portland cement in an amount of 30% by mass or less.

7. A hydraulic composition mixture material comprising the hydraulic composition according to any one of claims 1 to 6 and a nitrate compound, the hydraulic composition mixture material comprising the nitrate compound in an amount of 1 to 3 mass% calculated as nitrate ions relative to 100 mass% of the hydraulic composition.

8. A hydraulic composition mixture comprising the hydraulic composition according to any one of claims 1 to 6 and at least one of a fibrous material, an aggregate and a chemical admixture.

9. A hydraulic composition mixture comprising the hydraulic composition according to any one of claims 1 to 6, a nitrate compound, and at least one of a fiber material, an aggregate, and a chemical admixture, the hydraulic composition mixture comprising the nitrate compound in an amount of 1 to 3 mass% calculated as nitrate ions relative to 100 mass% of the hydraulic composition.

10. A hardened body, characterized in that it is formed from the hydraulic composition according to any one of claims 1 to 6.

11. The hardened body according to claim 10, characterized in that the surface is polished.

12. A hardened body, characterized in that it is formed from the hydraulic composition mixed material according to any one of claims 7 to 9.

13. The hardened body according to claim 12, characterized in that the surface is polished.