hydraulic materials

Abstract

To provide a hydraulic material that makes it possible to produce high-strength mortar without using only a small amount of Portland cement.SOLUTION: A hydraulic material contains Portland cement, gypsum powder, blast furnace slag powder and a stimulant. The stimulant is a compound having a sodium ion, a calcium ion or a magnesium ion forming an ionic bond with a phosphate ion, a monohydrogen phosphate ion, a dihydrogen phosphate ion, a nitrite ion, a thiosulfate ion, a chloride ion, a sulfate ion, a carbonate ion or a fluoride ion.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] This invention relates to hydraulic materials. [Background technology]

[0002] Patent Document 1, listed below, describes a hydraulic material containing Portland cement, anhydrous gypsum powder, and blast furnace slag powder. The same document also describes the production of high-strength mortar by mixing the hydraulic material with water. The Portland cement content of this hydraulic material is stated to be 90% by mass or more.

[0003] Incidentally, the production of Portland cement requires a cement calcination process. This cement calcination process emits a large amount of carbon dioxide. Therefore, from the perspective of reducing carbon dioxide emissions, it is preferable to reduce the amount of Portland cement used in hydraulic materials. However, when only a small amount of Portland cement is used as the hydraulic material, the strength of the mortar produced from the hydraulic material tends to be insufficient. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2020-183338 [Overview of the project] [Problems that the invention aims to solve]

[0005] Therefore, the inventors have conducted various studies on this matter and have found that even if a hydraulic material contains only a small amount of Portland cement, it is possible to produce high-strength mortar by mixing a predetermined stimulant into the hydraulic material. The present invention is based on this finding and aims to provide a hydraulic material that can produce high-strength mortar even if it contains only a small amount of Portland cement. [Means for solving the problem]

[0006] The hydraulic material according to the first item of the present invention comprises Portland cement, gypsum powder, blast furnace slag powder, and an irritant. The irritant is a compound in which sodium ions, calcium ions, or magnesium ions are ionically bonded to phosphate ions, monohydrogen phosphate ions, dihydrogen phosphate ions, nitrite ions, thiosulfate ions, chloride ions, sulfate ions, carbonate ions, or fluoride ions.

[0007] According to the first point, high-strength mortar can be produced even with only a small amount of Portland cement. This point will be explained in detail in the test examples described later.

[0008] The hydraulic material according to the second item of the present invention is characterized in that the stimulant is a mixture of two types of the aforementioned compounds.

[0009] According to the second point, it is possible to manufacture even higher-strength mortar. This point will be explained in detail in the test examples described later.

[0010] The hydraulic material according to the third item of the present invention is characterized in that the stimulant is at least one of the following: sodium monohydrogen phosphate, sodium chloride, calcium nitrite, calcium chloride, magnesium sulfate, magnesium carbonate, magnesium chloride, and trimagnesium phosphate.

[0011] According to the third point, it is possible to manufacture mortar with even higher strength. This point will be explained in detail in the test examples described later.

[0012] Here, as the Portland cement, any one of ordinary Portland cement, early-strength Portland cement, medium-heat Portland cement, low-heat Portland cement, sulfate-resistant Portland cement, or a mixture of two or more of these can be used. As the gypsum powder, for example, either anhydrous gypsum powder or dihydrate gypsum powder, or a mixture of these can be used.

[0013] The hydraulic material according to the fourth aspect of the present invention is such that the ratio of the mass of the Portland cement to the total mass of the Portland cement, the gypsum powder, the blast furnace slag powder, and the stimulant is 3% or less.

[0014] According to the fourth aspect, a higher-strength mortar can be produced. This point will be described in detail in the test examples described later.

[0015] The hydraulic material according to the fifth aspect of the present invention is such that the ratio of the mass of the gypsum powder to the total mass is 5% or more and 17% or less.

[0016] According to the fifth aspect, a higher-strength mortar can be produced. This point will be described in detail in the test examples described later.

[0017] In order to produce a high-strength mortar from the hydraulic material according to the first aspect above, the stimulant contains a first stimulant and a second stimulant, the first stimulant is an anhydride or hydrate of sodium hydrogen phosphate or magnesium phosphate, and the second stimulant is an anhydride or hydrate of calcium nitrite or calcium chloride, which is particularly preferable. Further, it is more preferable that the mass ratio of the second stimulant to the first stimulant is 1.5 or more, and / or the mass ratio of the stimulant to the blast furnace slag powder is 0.0400 or more and 0.0700 or less.

Advantages of the Invention

[0018] As described above, the present invention provides a hydraulic material that enables the production of high-strength mortar even when containing only a small amount of Portland cement. [Brief explanation of the drawing]

[0019] [Figure 1] Figure 1 is a graph showing the results of a test example of a hydraulic material according to one embodiment of the present invention, illustrating the relationship between the ratio of stimulants in the hydraulic material and the compressive strength of the mortar. [Figure 2] Figure 2 is a graph showing the results of a test example of a hydraulic material according to one embodiment of the present invention, illustrating the relationship between the type of stimulant used in the hydraulic material and the compressive strength of the mortar. [Figure 3] Figure 3 is a graph showing the results of a test example of a hydraulic material according to one embodiment of the present invention, illustrating the relationship between the type and combination of stimulants used in the hydraulic material and the compressive strength of the mortar. [Figure 4] Figure 4 is a graph showing the results of a test example of a hydraulic material according to one embodiment of the present invention, illustrating the relationship between the blast furnace slag powder content in the hydraulic material and the compressive strength of the mortar. [Figure 5] Figure 5 is a graph showing the results of a test example of a hydraulic material according to one embodiment of the present invention, illustrating the relationship between the Portland cement content of the hydraulic material and the compressive strength of the mortar. [Figure 6] Figure 6 is a graph showing the results of a test example of a hydraulic material according to one embodiment of the present invention, illustrating the relationship between the gypsum powder content of the hydraulic material and the compressive strength of the mortar. [Modes for carrying out the invention]

[0020] A hydraulic material according to one embodiment of the present invention will be described. The hydraulic material includes Portland cement, gypsum powder, blast furnace slag powder, and an irritant.

[0021] The stimulant is a compound in which sodium ions, calcium ions, or magnesium ions are ionically bonded to phosphate ions, monohydrogen phosphate ions, dihydrogen phosphate ions, nitrite ions, thiosulfate ions, chloride ions, sulfate ions, carbonate ions, or fluoride ions. This compound may also be in hydrate form.

[0022] To produce high-strength mortar by mixing hydraulic material, water, and fine aggregate, it is preferable to use a mixture of two of the above compounds as an agitator. Furthermore, it is preferable to use at least one of the following as an agitator: sodium monohydrogen phosphate, sodium chloride, calcium nitrite, calcium chloride, magnesium sulfate, magnesium carbonate, magnesium chloride, and trimagnesium phosphate, and it is particularly preferable to use the above seven agitators excluding sodium chloride.

[0023] As Portland cement, for example, any of the following can be used: ordinary Portland cement, rapid-hardening Portland cement, moderate-heat Portland cement, low-heat Portland cement, or sulfate-resistant Portland cement, or a mixture of two or more of these. As gypsum powder, either anhydrous gypsum powder or dihydrate gypsum powder, or a mixture of these, can be used.

[0024] To produce high-strength mortar by mixing hydraulic material, water, and fine aggregate, it is preferable that the ratio of the mass of Portland cement to the total mass of Portland cement, gypsum powder, blast furnace slag powder, and stimulant be 3% or less. Furthermore, it is preferable that the ratio of the mass of gypsum powder to this total mass be between 5% and 17%, and even more preferable that this ratio be between 7% and 12%.

[0025] The specific surface area of ​​blast furnace slag powder is, for example, 3800 cm². 2 / g or more 4300cm 2It is less than or equal to / g. In this specification, specific surface area refers to the specific surface area measured using a Blaine air permeation device. The specific method for measuring this specific surface area is specified in "JIS R 5201".

[0026] In order to produce a high-strength mortar from the hydraulic material according to this embodiment, it is particularly preferable that the stimulant contains a first stimulant and a second stimulant, wherein the first stimulant is an anhydrous or hydrate of sodium monohydrogen phosphate or trimagnesium phosphate, and the second stimulant is an anhydrous or hydrate of calcium nitrite or calcium chloride. It is even more preferable that the mass ratio of the second stimulant to the first stimulant is 1.5 or more and 7.0 or less. Furthermore, it is even more preferable that the mass ratio of the stimulant to the blast furnace slag powder (i.e., the ratio of the total mass of the first stimulant and the second stimulant to the mass of the blast furnace slag powder) is 0.0400 or more and 0.0700 or less.

[0027] Next, we will describe test examples and comparative examples of hydraulic materials according to one embodiment of the present invention. In test examples A1 to A4 shown in Table 2, test examples B1 to B21 shown in Table 3, and test examples C1 to C8 shown in Table 5, hydraulic materials were prepared by mixing ordinary Portland cement, gypsum powder, blast furnace slag powder, and an irritant. In comparative example 1 shown in Table 2, a hydraulic material was prepared by mixing ordinary Portland cement, gypsum powder, and blast furnace slag powder without using an irritant.

[0028] Furthermore, as gypsum powder, its specific surface area is 4680 cm². 2 The product used was anhydrous gypsum of type II manufactured by Soegawa Rikagaku Co., Ltd. Furthermore, ordinary Portland cement is a mixed powder consisting of cement clinker powder, dihydrate gypsum powder, and hemihydrate gypsum powder, as specified in JIS R 5210.

[0029] Furthermore, in these comparative examples and test examples, a mixture was prepared by mixing this hydraulic material with fine aggregate and water. Specifically, 450g of hydraulic material, 1350g of fine aggregate, and 225g of water were weighed out and mixed in a Hobart mixer in accordance with JIS R 5201 "Physical Test Methods for Cement". The mixed mixture was formed using a steel mold with internal dimensions of 4 × 4 × 16 cm. After 24 hours of molding, the mold was removed and sealed and cured in a room at 20°C until the age for the strength test. This yielded mortar. The compressive strength of this mortar was then measured. The compressive strength was measured in accordance with JIS R 5201 "Physical Test Methods for Cement".

[0030] Table 1 shows the parameters of the blast furnace slag powder used in Comparative Example 1, Test Examples A1-A4, Test Examples B1-B21, and Test Examples C1-C8, namely the chemical composition (from ig. loss to basicity) and density (g / cm³). 3 This indicates the chemical composition. The unit of chemical composition is mass%.

[0031] [Table 1]

[0032] Table 2 shows the relationship between the ratio of stimulants in hydraulic materials and the compressive strength of mortar. Here, the ratio of stimulants refers to the ratio of the mass of stimulants to the mass of the mixed powder consisting of Portland cement, gypsum powder, and blast furnace slag powder. In Comparative Example 1 and Test Examples A1-A4 shown in Table 2, the Portland cement content in the mixed powder was set to 3% by mass, the gypsum powder content to 30% by mass, and the blast furnace slag powder content to 67% by mass. In Test Examples A1-A4, calcium nitrite was used as the stimulant.

[0033] [Table 2]

[0034] In Table 2, the "3-day age" column shows the compressive strength of the mortar at 3 days of age (hereinafter referred to as "3-day strength"). The "7-day age" column shows the compressive strength of the mortar at 7 days of age (hereinafter referred to as "7-day strength"). The "28-day age" column shows the compressive strength of the mortar at 28 days of age (hereinafter referred to as "28-day strength"). The same applies to Tables 3, 5, 7, and 8, which will be discussed later.

[0035] Figure 1 is a graph showing the results for Comparative Example 1 and Test Examples A1-A4 shown in Table 2, illustrating the relationship between the ratio of the mass of the stimulant to the mass of the mixed powder and the compressive strength of the mortar. As shown in Figure 1, as the ratio of the mass of the stimulant increases, that is, as the stimulant content in the hydraulic material increases, the 3-day, 7-day, and 28-day strengths of the mortar all increase. In other words, it is considered that by mixing a stimulant into the hydraulic material, it is possible to produce a higher-strength mortar compared to when the hydraulic material is not mixed with a stimulant.

[0036] Table 3 shows the relationship between the type of stimulant used, the mixing pattern, the stimulant content, and the compressive strength of the mortar in test examples B1 to B21. Here, the mixing pattern refers to the composition of the hydraulic material shown in Table 4.

[0037] [Table 3]

[0038] [Table 4]

[0039] In test examples B1 to B21, as shown in Table 3, sodium nitrite (Na nitrite), sodium thiosulfate (Na thio), sodium monohydrogen phosphate (Na phosphate), sodium carbonate (Na carbonate), sodium chloride (Na chloride), calcium nitrite (Ca nitrite), calcium chloride (Ca chloride), calcium fluoride (Ca fluoride), calcium carbonate (Ca carbonate), magnesium sulfate (Mg sulfate), magnesium carbonate (Mg carbonate), or magnesium chloride (Mg chloride) were used as stimulants.

[0040] Figure 2 is a graph showing the results for some of the test examples B1 to B21 shown in Table 3, illustrating the relationship between the type of stimulant used in the hydraulic material and the compressive strength of the mortar. The bar graphs in Figure 2, from left to right, show the compressive strength of the mortar in test examples B1, B2, B4, B5, B6, B8, B10 to B14, and B16, respectively. The horizontal axis of Figure 2 indicates the type of stimulant used in these test examples.

[0041] As shown in Table 3, in all test examples, the 28-day strength of the mortar was at least 10 N / mm². 2 The strength has increased to a certain extent. In particular, when sodium monohydrogen phosphate, sodium chloride, calcium nitrite, calcium chloride, magnesium sulfate, magnesium carbonate, or magnesium chloride is used as an irritant, the 28-day strength of the mortar is 14 N / mm² in all cases. 2 It exceeds [value]. Furthermore, when using the six irritants listed above, excluding sodium chloride, the 28-day strength of the mortar was 20 N / mm² in all cases. 2 It exceeds that.

[0042] Figure 3 is a graph showing the results for some of the test examples B1 to B21 shown in Table 3, illustrating the relationship between the type and combination of stimulants used in the hydraulic material and the compressive strength of the mortar. The bar graphs in Figure 3, from left to right, show the compressive strength of the mortar in test examples B7, B8, B15, B16, B9, B10, B3, B4, and B17 to B20, respectively. The horizontal axis of Figure 3 indicates the type and combination of stimulants used in these test examples.

[0043] As shown in Table 3, in Test Examples B1 to B16, one type of compound was used as the stimulant, whereas in Test Examples B17 to B21, a mixture of two types of compounds was used as the stimulant. And, as shown in Table 3, in Test Examples B1 to B16, the 28-day strength of the mortar was at most 42.2 N / mm 2 whereas in Test Examples B17 to B21, the 28-day strength of the mortar exceeded 45 N / mm 2 in all cases.

[0044] Figure 4 is a graph showing the results in some of Test Examples B1 to B21 shown in Table 3, and shows the relationship between the blast furnace slag powder content in the hydraulic material and the compressive strength of the mortar. The bar graph shown in Figure 4 shows the compressive strength of the mortar in Test Examples B17 to B21 from left to right. The horizontal axis of Figure 4 shows the blast furnace slag powder content in the hydraulic material used in these test examples.

[0045] As shown in Table 3, the same stimulant was used in Test Examples B20 and B21. And, as shown in Figure 4, in Test Example B20, the blast furnace slag powder content was 65.33% by mass, whereas in Test Example B21, the blast furnace slag powder content was 77.90% by mass. Also, in Test Example B20, the 28-day strength of the mortar was 54.0 N / mm 2 whereas in Test Example B21, the 28-day strength of the mortar was 64.3 N / mm 2 in all cases.

[0046] That is, comparing Test Examples B20 and B21, it can be seen that the 28-day strength of the mortar increased as the blast furnace slag powder content in the hydraulic material increased. In addition, in Test Example B21, the blast furnace slag powder content was higher than in Test Examples B17 to B19, and the 28-day strength of the mortar was correspondingly higher.

[0047] Therefore, the following conclusion can be drawn from the results shown in Figures 1 to 4. In a hydraulic material containing Portland cement, gypsum powder, blast furnace slag powder, and an stimulant, if the compounds shown in Table 3 are used as the stimulant, a mortar with higher strength can be produced compared to when no stimulant is used. Specifically, as shown in Table 3, these compounds include sodium nitrite, sodium thiosulfate, monohydrogen phosphate, sodium carbonate, sodium chloride, calcium nitrite, calcium chloride, calcium fluoride, calcium carbonate, magnesium sulfate, magnesium carbonate, or magnesium chloride.

[0048] In particular, as shown in Table 3 and Figure 3, using a mixture of two of the above compounds as a stimulant allows for the production of even higher-strength mortar. Furthermore, using sodium monohydrogen phosphate, sodium chloride, calcium nitrite, calcium chloride, magnesium sulfate, magnesium carbonate, or magnesium chloride as a stimulant allows for the production of even higher-strength mortar. In particular, using six of the above stimulants excluding sodium chloride as a stimulant allows for a 28-day strength of mortar of 20 N / mm². 2 It can be done to the extent of above.

[0049] Here, we examine the principle by which such stimulants increased the 28-day strength of mortar. As shown in Figure 4, the 28-day strength of mortar increased as the blast furnace slag powder content in the hydraulic material increased. In other words, it is thought that the 28-day strength of mortar increased due to a reaction between the ions contained in the stimulant and the blast furnace slag powder during the mixing of the hydraulic material and water. Therefore, it is thought that any stimulant containing ions similar to those contained in the stimulants shown in Table 3 can increase the 28-day strength of mortar.

[0050] In other words, any compound that can be used as a stimulant is one in which a sodium ion, calcium ion, or magnesium ion is ionically bonded to a monohydrogen phosphate ion, nitrite ion, thiosulfate ion, chloride ion, sulfate ion, carbonate ion, or fluoride ion.

[0051] Furthermore, it is thought that monohydrogen phosphate ions changed to dihydrogen phosphate ions during the mixing of hydraulic materials with water, thereby increasing the 28-day strength of the mortar. For this reason, compounds in which dihydrogen phosphate ions are ionically bonded with sodium ions, calcium ions, or magnesium ions can also be used as stimulants. Alternatively, compounds in which phosphate ions, which change to dihydrogen phosphate ions in water, are ionically bonded with sodium ions, calcium ions, or magnesium ions can also be used as stimulants.

[0052] Table 5 shows the relationship between the composition of the hydraulic material and the compressive strength of the mortar. In Test Examples C1 to C8, the stimulant content in the hydraulic material was set to 5% by mass in all cases, and a mixture of calcium chloride and sodium monohydrogen phosphate was used as the stimulant. In Test Examples C1 to C4, the Portland cement content was the same, but the gypsum powder content differed. In Test Examples C2, C5 to C8, the Portland cement content differed, but the gypsum powder content was the same.

[0053] [Table 5]

[0054] Figure 5 is a graph showing the results for some of the test examples C1 to C8 shown in Table 5, illustrating the relationship between the Portland cement content in hydraulic materials and the compressive strength of the mortar. Specifically, each plot in Figure 5 corresponds to test examples C2, C5 to C8 shown in Table 5.

[0055] As shown in Figure 5, if the Portland cement content is 3% by mass or less, the 28-day strength of the mortar is 50 N / mm². 2 It exceeds [value]. However, when the Portland cement content is between 3% by mass and approximately 20% by mass, the 28-day strength is lower than when the Portland cement content is 3% by mass or less.

[0056] Therefore, the following conclusion can be drawn from the results shown in Figure 5: In a hydraulic material containing Portland cement, gypsum powder, blast furnace slag powder, and an irritant, if the ratio of the mass of Portland cement to the total mass of Portland cement, gypsum powder, blast furnace slag powder, and irritant is 3% or less, then even if only a small amount of Portland cement is included in the hydraulic material, a higher-strength mortar can be produced.

[0057] Figure 6 is a graph showing the results for some of the test examples C1 to C8 shown in Table 5, illustrating the relationship between the gypsum powder content in hydraulic materials and the compressive strength of the mortar. Specifically, each plot in Figure 6 corresponds to test examples C1 to C4 shown in Table 5.

[0058] As shown in Figure 6, the graph showing the relationship between gypsum powder content and the 28-day strength of mortar is presumed to be an upward-convex curve. Based on this, it is thought that if the gypsum powder content is between 5% by mass and 17% by mass, the 28-day strength of the mortar will be higher compared to when the gypsum powder content is outside this range. In particular, if the gypsum powder content is between 7% by mass and 12% by mass, the 28-day strength of the mortar will be 50 N / mm². 2 It is thought to exceed this.

[0059] Therefore, the following conclusion can be drawn from the results shown in Figure 6. In a hydraulic material containing Portland cement, gypsum powder, blast furnace slag powder, and an irritant, if the ratio of the mass of gypsum powder to the total mass of Portland cement, gypsum powder, blast furnace slag powder, and irritant is 5% to 17%, then even if the hydraulic material contains only a small amount of Portland cement, a higher-strength mortar can be produced. In particular, if this ratio is 7% to 12%, the 28-day strength of the mortar can be increased to 50 N / mm². 2 It can be done to the extent of above.

[0060] As mentioned above, using two types of stimulants in hydraulic materials increases the strength of the mortar compared to using only one type. Furthermore, comparing test examples B19-B21 (using a combination of monohydrogen phosphate and calcium chloride or calcium nitrite as stimulants) shown in Table 3 with test examples B17 and B18 (using a combination of magnesium chloride and calcium chloride or calcium nitrite as stimulants), the 3-day, 7-day, and 28-day strengths of the mortar are all higher in test examples B19-B21 compared to test examples B17 and B18. From this, it can be seen that using monohydrogen phosphate and calcium chloride or calcium nitrite as the combination of these two stimulants is particularly preferable.

[0061] When a compound containing phosphate ions is used as a stimulant in combination with calcium chloride or calcium nitrite, it is thought that dihydrogen phosphate ions are generated in the mortar manufacturing process (i.e., the mixing process of Portland cement), stimulating the blast furnace slag powder, similar to the case when using sodium monohydrogen phosphate. Therefore, it is assumed that even when a compound containing phosphate ions is used in combination with calcium chloride or calcium nitrite instead of sodium monohydrogen phosphate, mortar with a strength comparable to that of Test Examples B19 to B21 can be produced.

[0062] Below, we describe test examples D1-D4, E1-E4, and comparative example 2 for confirming and comparing the strength of mortar when trimagnesium phosphate (a compound containing phosphate ions) is used in combination with calcium chloride or calcium nitrite as a stimulant. Regarding these test examples and comparative examples, we will only explain the differences from test example A1 described above; other points will be omitted.

[0063] Table 6 shows the parameters of the blast furnace slag powder used in Comparative Example 2, Test Examples D1-D4, and E1-E4, including chemical composition (from the "ig.loss" column to the "Total" column) and density (g / cm³). 3 ) and specific surface area (cm²) 2 The values ​​shown are per g. The unit of chemical composition is mass percent. "Total" is the sum of the values ​​for the items from "ig.loss" to "MnO" shown in Table 6.

[0064] [Table 6]

[0065] Table 7 shows the relationship between the type and proportion of stimulants in hydraulic materials and the compressive strength of the mortar. In Table 7, the "Type and Proportion of Stimulants" column refers to the type and content of stimulants used in test examples D1-D4 and E1-E4.

[0066] [Table 7]

[0067] In Test Examples D1-D4 and E1-E4 shown in Table 7, the Portland cement content in the hydraulic material was set to 3% by mass, the blast furnace slag powder content in the hydraulic material was set to 82% by mass, the anhydrous gypsum powder content in the hydraulic material was set to 10% by mass, and the stimulant content in the hydraulic material (total content of the two stimulants in Test Examples E1-E4, which use two types of stimulants) was set to 5% by mass. In Comparative Example 2 shown in Table 7, the Portland cement content and anhydrous gypsum powder content were the same as in Test Examples D1-D4 and E1-E4, but instead of using a stimulant, the blast furnace slag powder content was adjusted to 87% by mass.

[0068] As shown in Table 7, in Test Example D4, the 28-day strength of the mortar was higher compared to Test Examples D1-D3 and Comparative Example 2. Furthermore, in Test Examples E1-E4, both the 7-day and 28-day strengths of the mortar were higher than in any of Test Examples D1-D4. In addition, the 3-day strength of the mortar was higher in Test Examples E1 and E3 than in any of Test Examples D1-D4, and in Test Examples E2 and E4, it significantly exceeded that of Test Examples D3 and D4, reaching almost the same level as Test Examples D1 and D2. Furthermore, in Test Examples E2 and E4, the 28-day strength of the mortar was higher compared to Test Examples E1 and E3.

[0069] In other words, based on Test Examples D1 to D4 and Comparative Example 2, it can be said that using trimagnesium phosphate as a stimulant in hydraulic materials is particularly preferable for producing mortar with high strength (especially the 28-day strength, which is considered the most important in building design among the 3-day, 7-day, and 28-day strengths) from hydraulic materials.

[0070] Furthermore, based on test examples B19 to B21 shown in Table 3, it can be said that in order to produce high-strength mortar, it is preferable to use a combination of sodium monohydrogen phosphate and calcium chloride or calcium nitrite as a stimulant in hydraulic materials. Moreover, based on test examples E1 to E4 shown in Table 7, it can be seen that high-strength mortar can also be produced by using trimagnesium phosphate in combination with calcium chloride or calcium nitrite instead of sodium monohydrogen phosphate.

[0071] In the following, sodium monohydrogen phosphate or trimagnesium phosphate will be referred to as the "first irritant," and calcium nitrite or calcium chloride will be referred to as the "second irritant."

[0072] Below, we will describe test examples F1 to F7 regarding the relationship between the total content of the first and second irritants and the strength of the mortar, and the relationship between the mass ratio of the second irritant to the first irritant and the strength of the mortar. Note that for these test examples, we will only explain the differences from the aforementioned test example A1, and omit explanations for other points.

[0073] Table 8 shows the relationship between the composition of the hydraulic material and the compressive strength of the mortar. In test examples E1 to E4 shown in Table 7, the total content of the first and second stimulants was standardized at 5%, and the mass ratio of the second stimulant to the first stimulant was standardized at 4. In contrast, in test examples F1 to F7 shown in Table 8, the total content of the first and second stimulants was set to 3%, 4%, or 5%, and the mass ratio of the second stimulant to the first stimulant was set to 1.0, 1.5, or 4.0. In test examples F1 to F7, sodium monohydrogen phosphate (Na phosphate) was used as the first stimulant, and calcium nitrite (Ca nitrite) was used as the second stimulant.

[0074] [Table 8]

[0075] Comparing test examples F1 to F3 shown in Table 8, the 3-day strength, 7-day strength, and 28-day strength all increased as the stimulant content in the hydraulic material increased. In test examples F2 and F3, the 3-day strength, 7-day strength, and 28-day strength were all higher than in test example F1. Furthermore, the difference in 3-day strength between test example F2 and test example F3 was 1.0 N / mm². 2 The difference in strength over 7 days was 3.5 N / mm². 2 The difference in intensity over 28 days was 6.6 N / mm². 2 Thus, there was no significant difference in the overall strength of the mortar. In contrast, the difference in 3-day strength between test example F1 and test example F2 was 3.8 N / mm². 2 The difference in intensity over 7 days was 9.3 N / mm². 2 The difference in strength over 28 days was 14.2 N / mm². 2 As a result, there was a significant difference in the overall strength of the mortar.

[0076] Therefore, it is preferable that the stimulant content in the hydraulic material (i.e., the total content of the first and second stimulants) be in the same range as in Test Examples F2 and F3 (3.5% by mass or more and 8% by mass or less). Furthermore, it is preferable that the ratio of the stimulant to the blast furnace slag powder (the material stimulated by the stimulant) be in the same range as in Test Examples F2 and F3 (0.0400 or more and 0.0700 or less). This ratio was 0.0357 in Test Example F1, 0.0482 in Test Example F2, and 0.0610 in Test Example F3.

[0077] Comparing test examples F3 to F5 shown in Table 8, the 3-day, 7-day, and 28-day strengths all increased as the ratio of calcium nitrite to sodium monohydrogen phosphate increased. In test examples F4 and F5, the 3-day, 7-day, and 28-day strengths were higher than in test example F3. Furthermore, the difference in 28-day strength between test example F4 and test example F5 was 0.2 N / mm². 2 While the difference in strength between test example F3 and test example F4 is small, the difference in strength over 28 days is 2.8 N / mm². 2 And it is growing.

[0078] Therefore, it can be said that it is preferable for the ratio of the second stimulant to the first stimulant to be about the same as that of test examples F4 and F5 (1.5 to 7.0).

[0079] Comparing test examples F4 and F6 shown in Table 8, test example F6 has a lower Portland cement content than test example F4, but its 28-day strength is higher. Similarly, comparing test examples F5 and F7 shown in Table 8, test example F7 has a lower Portland cement content than test example F5, but its 28-day strength is higher.

[0080] Therefore, it can be said that it is particularly preferable for the Portland cement content in the hydraulic material to be similar to that of test examples F6 and F7 (0.5% by mass or more and 2% by mass or less).

[0081] Incidentally, the calcium chloride used in test examples D1, E1, and E2 is anhydrous, the calcium nitrite used in test examples D2, E3, and E4 is monohydrate, the sodium monohydrogen phosphate used in test examples D3, E1, and E3 is dodecahydrate, and the trimagnesium phosphate used in test examples D4, E2, and E4 is octahydrate. Note that the reagent name for the sodium monohydrogen phosphate used in test examples D3, E1, and E3 is "disodium hydrogen phosphate dodecahydrate".

[0082] In the mortar manufacturing process (i.e., the mixing process of Portland cement), even if the stimulant is in its anhydrous form, it will hydrate to become a hydrate. Therefore, it is thought that the strength of the mortar will not vary significantly depending on whether an anhydrous or hydrated form of the stimulant is used. In other words, it is thought that the same level of mortar strength will be achieved whether anhydrous or hydrated forms of the aforementioned sodium monohydrogen phosphate, trimagnesium phosphate, calcium nitrite, and calcium chloride are used.

[0083] Thus, according to the above embodiment, even when using a hydraulic material containing only a small amount of Portland cement compared to conventional hydraulic materials, high-strength mortar can be produced. In particular, when using the hydraulic materials related to test examples F6 and F7 shown in Table 8 above, even though the Portland cement content in this hydraulic material is 1% by mass, the 28-day strength of the mortar is 60 N / mm². 2 This allows for increased strength. In other words, high-strength mortar can be produced without using large amounts of Portland cement. Therefore, the amount of Portland cement used in hydraulic materials can be reduced, and the amount of carbon dioxide emitted from cement firing equipment can be reduced by approximately 90%. This contributes to reducing the amount of carbon dioxide generated throughout the entire manufacturing process of hydraulic materials.

[0084] Furthermore, according to the above embodiment, high strength can be achieved in mortar obtained by curing a mixture of hydraulic material and water at 20°C. Therefore, there is no need to perform autoclave curing, steam curing, or heat curing to achieve the strength of the mortar. In other words, energy required for curing this mixture can be saved.

Claims

1. A hydraulic material comprising Portland cement, gypsum powder, blast furnace slag powder, and an irritant, The content of the blast furnace slag fine powder relative to the total mass of the Portland cement, the gypsum powder, the blast furnace slag powder, and the stimulant is 63% or more. The hydraulic material is characterized in that the stimulant is magnesium chloride, a mixture of calcium chloride and magnesium chloride, a mixture of calcium nitrite and magnesium chloride, a mixture of calcium chloride and sodium monohydrogen phosphate, a mixture of calcium chloride and trimagnesium phosphate, or a mixture of calcium nitrite and sodium monohydrogen phosphate.

2. The hydraulic material according to claim 1, wherein the mass ratio of the stimulant to the blast furnace slag powder is 0.0400 or more and 0.0700 or less.

3. The hydraulic material according to claim 1 or 2, characterized in that the Portland cement is any of ordinary Portland cement, rapid-hardening Portland cement, moderate-heat Portland cement, low-heat Portland cement, sulfate-resistant Portland cement, or a mixture of two or more of these.

4. The hydraulic material according to any one of claims 1 to 3, characterized in that the gypsum powder is one of anhydrous gypsum powder, one of dihydrate gypsum powder, or a mixture thereof.

5. The hydraulic material according to any one of claims 1 to 4, characterized in that the ratio of the mass of Portland cement to the total mass of Portland cement, gypsum powder, blast furnace slag powder, and stimulant is 3% or less.

6. The hydraulic material according to any one of claims 1 to 5, characterized in that the ratio of the mass of the gypsum powder to the total mass of the Portland cement, the gypsum powder, the blast furnace slag powder, and the stimulant is 5% or more and 17% or less.

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