Cementitious material

Abstract

To suppress an increase in the cost of a cement-based material and a decrease in the service life of a structure while improving the compressive strength of the structure made of mortar or concrete using the cement-based material.SOLUTION: The cement-based material is a mixture of cement, bamboo charcoal, and blast furnace slag fine powder, and is used for forming a structure made of mortar or concrete. In the structure thus formed, pollen can be adsorbed by the bamboo charcoal mixed with the cement-based material. In the cement-based material, the weight replacement ratio of the blast furnace slag fine powder to the total weight is more than 0% and 60% or less. Accordingly, it is possible to suppress an increase in the cost of the cement-based material and a decrease in the service life of the structure while improving the compressive strength of the structure made of mortar or concrete using the cement-based material.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to cement-based materials. [Background technology]

[0002] Patent Document 1 discloses a cementitious material that is a mixture of cement, bamboo charcoal, and ground granulated blast furnace slag. In structures made of mortar or concrete that use such cementitious materials, the bamboo charcoal mixed into the cementitious material makes it possible to adsorb pollen, and the ground granulated blast furnace slag mixed into the cementitious material increases compressive strength. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2007-197291 Summary of the Invention [Problem to be solved by the invention]

[0004] The compressive strength of structures formed from the above cementitious materials increases with the amount of ground granulated blast furnace slag mixed into the cementitious materials, but if the amount of ground granulated blast furnace slag is too high, it will result in increased costs and a reduced service life.

[0005] The decrease in the service life of structures made from cementitious materials due to the large amount of ground granulated blast furnace slag mixed into them is related to the carbonation of the structure caused by the ground granulated blast furnace slag. Specifically, structures made of mortar or concrete using cementitious materials are alkaline due to the cement, making the reinforcing steel bars and other components inside the structures less susceptible to rust. However, when a large amount of ground granulated blast furnace slag is mixed into the cementitious material, the amount of cement in the cementitious material decreases relatively, accelerating the carbonation of the structure. As a result, the structure is carbonized early, making the reinforcing steel bars and other components inside the structure more susceptible to rust, thereby reducing the service life of the structure. [Means for solving the problem]

[0006] The means for solving the above problems and their effects will be described below. The cementitious material that solves the above problems is a mixture of cement, bamboo charcoal, and ground granulated blast furnace slag, and the weight substitution rate of the ground granulated blast furnace slag to the total weight is greater than 0% and less than or equal to 60%.

[0007] According to the above configuration, when mixing the ground granulated blast furnace slag with the cementitious material, the weight substitution rate of the ground granulated blast furnace slag to the total weight of the cementitious material is set to be greater than 0% and not more than 60%, thereby improving the compressive strength of structures made of mortar or concrete using the cementitious material, while suppressing an increase in the cost of the cementitious material and a decrease in the service life of the structures.

[0008] In the cementitious material, it is considered that the volume substitution rate of bamboo charcoal relative to the total volume is greater than 0% and not more than 30%. The more bamboo charcoal is mixed into the cementitious material, the greater the amount of pollen that can be adsorbed by the bamboo charcoal in structures made of mortar or concrete using the cementitious material. However, if too much bamboo charcoal is mixed into the cementitious material, the compressive strength of the structure decreases. According to the above configuration, when mixing bamboo charcoal into the cementitious material, the volume replacement rate of bamboo charcoal relative to the total volume of the cementitious material is greater than 0% and less than 30%. This allows the structure made of mortar or concrete using the cementitious material to have the necessary amount of pollen adsorption while ensuring the necessary compressive strength of the structure.

[0009] In the cementitious material, bamboo charcoal may be used as fine aggregate. The bamboo charcoal preferably has a size of 1.7 mm or more and 5 mm or less. The ground granulated blast furnace slag may be that specified in JIS A6206. It is more preferable that the ground granulated blast furnace slag be ground granulated blast furnace slag 8000 specified in JIS A6206. [Brief explanation of the drawings]

[0010] [Figure 1] Graph showing the results of an experiment to measure the compressive strength of structures made of mortar and concrete using cement-based materials. [Figure 2] Graph showing the results of an experiment to measure the compressive strength of structures made of mortar and concrete using cement-based materials. [Figure 3] Graph showing the results of an experiment to measure the compressive strength of structures made of mortar and concrete using cement-based materials. [Figure 4] Graph showing the results of an experiment to measure the compressive strength of structures made of mortar and concrete using cement-based materials. [Figure 5] Graph showing the results of an experiment to measure the amount of pollen adsorption on structures made of mortar and concrete using cement-based materials. [Figure 6] Graph showing the results of an experiment to measure the pollen adsorption area ratio for structures made of mortar and concrete using cement-based materials. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, one embodiment of the cement-based material will be described with reference to FIGS. The cementitious material is formed by mixing cement, bamboo charcoal, and ground granulated blast furnace slag. The bamboo charcoal is considered to be fine aggregate, i.e., 1.7 mm or more and 5 mm or less in size. The ground granulated blast furnace slag may be that specified in JIS A6206, and it is more preferable to use ground granulated blast furnace slag 8000 specified in JIS A6206.

[0012] The ground granulated blast furnace slag is mixed with the cementitious material as follows: That is, the weight substitution rate X1 of the ground granulated blast furnace slag to the total weight of the cementitious material is set to be greater than 0% and not more than 60%. Note that the weight substitution rate X1 may be set to be greater than 0% and not more than 55%, or greater than 0% and not more than 50%.

[0013] The bamboo charcoal is mixed with the cementitious material as follows: the volume substitution rate X2 of the bamboo charcoal relative to the total volume of the cementitious material is greater than 0% and less than or equal to 30%.

[0014] <Experiment 1> Next, an experiment to measure the compressive strength of a structure made of mortar or concrete using the above cementitious material, specifically an experiment to measure the change in compressive strength of the structure when the weight replacement rate X1 and the volume replacement rate X2 are changed, will be described with reference to Figures 1 to 4. The graphs in Figures 1 to 4 show the results of this experiment. In these graphs, the horizontal axis represents the number of days elapsed, and the vertical axis represents compressive strength.

[0015] In the graph of Fig. 1, the symbols "○", "□", "◇", and "△" indicate the compressive strength of the structure when the volume substitution rate X2 is changed to 0%, 10%, 20%, and 30% under the condition that the weight substitution rate X1 is 0%. In the graph of Fig. 2, the symbols "○", "□", "◇", and "△" indicate the compressive strength of the structure when the weight substitution rate X1 is changed to 0%, 20%, 40%, and 60% under the condition that the volume substitution rate X2 is 10%. In the graph of Fig. 3, the symbols "○", "□", "◇", and "△" indicate the compressive strength of the structure when the weight substitution rate X1 is changed to 0%, 20%, 40%, and 60% under the condition that the volume substitution rate X2 is 20%. In the graph of Figure 4, "○", "□", "◇", and "△" indicate the compressive strength of the structure when the weight substitution rate X1 is changed to 0%, 20%, 40%, and 60% under the condition that the volume substitution rate X2 is 30%.

[0016] From the experimental results shown in the graphs of Figures 1 to 4, it can be seen that the compressive strength of the structure formed from the above cementitious material increases as the amount of ground granulated blast furnace slag mixed with the cementitious material increases, and it can also be seen that the compressive strength of the structure decreases as the amount of bamboo charcoal mixed with the cementitious material increases.

[0017] <Experiment 2> Next, an experiment to measure the amount of pollen adsorption and adsorption area ratio for structures made of mortar or concrete using the above cement-based materials will be described with reference to Figures 5 and 6. The graphs in Figures 5 and 6 show the results of this experiment. In the graph of Figure 5, the vertical axis represents the weight change due to pollen adsorption in the test specimen of the above experiment, and the horizontal axis represents the volume replacement rate X2. In the graph of Figure 6, the vertical axis represents the pollen adsorption area rate, which is the ratio of the area where pollen is adsorbed to the total area of ​​the test specimen of the above experiment, and the horizontal axis represents the volume replacement rate X2.

[0018] As shown in Figure 5, the weight change (increase) due to pollen adsorption in the test specimen increases as the volume replacement rate X2 increases from 0% to 10%, 20%, and 30%. Also, as shown in Figure 6, the pollen adsorption area rate due to pollen adsorption in the test specimen increases as the volume replacement rate X2 increases from 0% to 10%, 20%, and 30%.

[0019] The experimental results shown in the graphs of Figures 5 and 6 indicate that the more bamboo charcoal is mixed into the cementitious material, the greater the pollen adsorption amount and adsorption area ratio of the structure formed from the cementitious material. However, as mentioned above, the more bamboo charcoal is mixed into the cementitious material, the lower the compressive strength of the structure.

[0020] Next, the effects of the cement-based material of this embodiment will be described. (1) In structures made of mortar or concrete using the above-mentioned cementitious materials, bamboo charcoal mixed into the cementitious material can adsorb pollen. However, mixing bamboo charcoal into the cementitious material reduces the compressive strength of the structure. To prevent this, blast furnace slag powder is mixed into the cementitious material containing bamboo charcoal. When mixing the blast furnace slab powder into the cementitious material, the weight substitution ratio X1 of the blast furnace slag powder to the total weight of the cementitious material is set to be greater than 0% and less than or equal to 60%. This can improve the compressive strength of structures made of mortar or concrete using the cementitious material, while suppressing the increase in the cost of the cementitious material and the shortening of the service life of the structure.

[0021] (2) The more bamboo charcoal is mixed into the cementitious material, the greater the amount of pollen that can be adsorbed by the bamboo charcoal in structures made of mortar or concrete using the cementitious material. However, if too much bamboo charcoal is mixed into the cementitious material, the compressive strength of the structure decreases. Taking this into consideration, when mixing bamboo charcoal into the cementitious material, the volume substitution rate X2 of the bamboo charcoal relative to the total volume of the cementitious material is set to be greater than 0% and less than 30%. This allows the structure made of mortar or concrete using the cementitious material to have the necessary amount of pollen adsorption while ensuring the necessary compressive strength of the structure.

[0022] The above embodiment can be modified as follows, for example: The above embodiment and the following modifications can be combined and implemented within the scope of technical compatibility. The bamboo charcoal mixed into the cementitious material does not necessarily have to be used as fine aggregate. In this case, the bamboo charcoal may have a size outside the range of 1.7 mm to 5 mm.

[0023] The ground granulated blast furnace slag to be mixed with the cementitious material may be other than the ground granulated blast furnace slag 8000 specified in JIS A6206, such as ground granulated blast furnace slag 3000, ground granulated blast furnace slag 4000, or ground granulated blast furnace slag 6000.

[0024] The granulated blast furnace slag mixed with cementitious materials does not necessarily have to be specified in JIS A6206.

Claims

1. A cement-based material made by mixing cement, bamboo charcoal, and ground granulated blast furnace slag, A cement-based material in which the weight substitution rate of the ground granulated blast furnace slag to the total weight is greater than 0% and not more than 60%.

2. 2. The cement-based material according to claim 1, wherein the volume substitution rate of the bamboo charcoal relative to the total volume is greater than 0% and less than 30%.

3. The cement-based material according to claim 2, wherein the bamboo charcoal is used as fine aggregate.

4. 4. The cement-based material according to claim 3, wherein the bamboo charcoal has a size of 1.7 mm or more and 5 mm or less.

5. The cement material according to any one of claims 1 to 4, wherein the ground granulated blast furnace slag is specified in JIS A6206.

6. 6. The cementitious material according to claim 5, wherein the ground granulated blast furnace slag is ground granulated blast furnace slag 8000 as specified in JIS A6206.

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