Diatomaceous earth-containing concrete

Abstract

The objective of the present invention is to provide concrete having a novel composition and a construction method for greening, by means of bryophytes, a slope or the like hardened with concrete.　Provided is a method for spraying diatomaceous earth-containing ready-mixed concrete comprising diatomaceous earth, cement and water, onto a construction surface, the method involving: mixing the diatomaceous earth and the cement in a state in which the water is not added; adding the water during spraying to form ready-mixed concrete; and spraying the ready-mixed concrete. Also provided is diatomaceous earth-containing ready-mixed concrete comprising diatomaceous earth, cement and water, wherein a thickener and a gelling agent are contained in an amount of 0.25-10 wt% with respect to the total of raw materials other than the water. According to the method for spraying the diatomaceous earth-containing ready-mixed concrete and the diatomaceous earth-containing ready-mixed concrete according to the present invention, spraying the diatomaceous earth-containing ready-mixed concrete onto a slope or the like hardened with concrete makes it possible to promote the adhesion and growth of bryophytes, thereby allowing greening of concrete slopes or the like.

Description

Diatomaceous earth-containing concrete

[0001] The present invention relates to a technique for greening existing concrete slopes with moss. More specifically, it relates to concrete that is sprayed onto existing concrete and is suitable for promoting the attachment and growth of moss, and to the greening of existing concrete slopes with moss using the same.

[0002] Greening has been practiced by spraying seedlings or installing vegetation sheets on concrete-hardened slopes. Porous concrete exists for purposes such as water purification, greening, and permeability, and is used in riverbank construction. One application of this porous concrete is concrete in which diatomaceous earth is mixed with cement as a lightweight aggregate (Patent Document 1

[0012] ). However, these concretes are primarily intended to function as structures, and this is reflected in the concrete's mix and structure. Furthermore, in the case of porous concrete for greening, water-retaining materials and fertilizers are filled into the voids, and in Patent Document 1, natural organic fibers are also mixed in (Patent Document 1

[0014] ,

[0016] ).

[0003] On the other hand, there is an invention in which concrete is divided into two layers, with a layer of concrete for greening placed on top of the concrete layer that ensures the required strength (for example, Patent Document 2). In addition, this invention also mixes moss into the concrete for greening. However, this invention does not mention diatomaceous earth. Furthermore, while there is a reference to the porosity required for moss to settle in the concrete for greening (ibid.

[0044] ,

[0053] ,

[0054] ), moss does not tolerate the high pH caused by cement well. In fact, when the cement ratio is 15%, the number of moss germinations is zero (ibid. [Table 3]). Furthermore, while there is a reference to panel-shaped and block-shaped concrete, there is no reference to spraying concrete.

[0004] Generally, mosses do not require soil, fertilizer, or watering to grow, and can grow on rainwater alone, so they can be found thriving on soilless surfaces such as concrete or asphalt. However, even if the gametophytes and spores of mosses reach these surfaces and attach to them, it takes several years for them to form colonies and flourish.

[0005] JP 2002-12479 A JP 2010-104271 A

[0006] An object of the present invention is to provide a concrete having a new composition and a construction method for greening concreted slopes and the like with moss plants.

[0007] To solve the above problems, the inventors conceived the idea of ​​greening existing concrete slopes and concrete bridge piers by spraying them with concrete that allows moss plants to attach and promote their growth. Furthermore, considering the need to maintain the humidity of the concrete surface in order to hasten the formation of moss colonies, they came up with the idea of ​​using diatomaceous earth, which has high water retention, as an aggregate. Furthermore, after extensive research, they discovered that in order to disperse and mix diatomaceous earth, which hardens when wet, into cement, it is effective to spray the concrete using a dry spraying method, or to add a thickener / gelling agent in the case of a wet spraying method, and thus arrived at the present invention. Specifically, the present invention is as follows: 1. Diatomaceous earth-containing ready-mix concrete consisting of diatomaceous earth, cement, and water, in which the weight ratio of diatomaceous earth to cement is 5:95 to 70:30. 2. 2. A method for spraying diatomaceous earth-containing ready-mixed concrete consisting of diatomaceous earth, cement, and water onto a work surface, comprising mixing diatomaceous earth and cement without adding water, and adding water when spraying to form ready-mixed concrete, which is then sprayed. 3. A diatomaceous earth-containing ready-mixed concrete consisting of diatomaceous earth, cement, and water, which contains 0.25 to 10% by weight of a thickener / gelling agent relative to the total of the ingredients other than water. 4. The diatomaceous earth-containing ready-mixed concrete of 3, wherein the thickener / gelling agent is one of cellulose ether, carrageenan, xanthan gum, and alginate, or a mixture of two or more of these. 5. A diatomaceous earth-containing ready-mixed concrete consisting of diatomaceous earth, cement, and water, which contains a mixture of moss plant and 0.25 to 30% by weight of an aqueous solution of the thickener / gelling agent. 6. The diatomaceous earth-containing ready-mixed concrete of 5 above, wherein the thickener / gelling agent is any one of cellulose ether, carrageenan, xanthan gum, and alginate, or a mixture of any two or more of these. 7. Concrete obtained by hardening the ready-mixed concrete of any one of 1, 3 to 6 above. 8. Concrete obtained by hardening the ready-mixed concrete of any one of 1, 3 to 6 above on top of existing concrete. 9. The concrete of 8 above, the edges of which have been waterproofed.10. Diatomaceous earth-containing ready-mixed concrete for promoting the growth and growth of moss, using the diatomaceous earth-containing ready-mixed concrete of any one of 1, 3, or 5. 11. A method for greening existing concrete with moss, comprising spraying diatomaceous earth-containing ready-mixed concrete onto the existing concrete using the spraying method of 2, and promoting the growth and growth of moss using the diatomaceous earth-containing ready-mixed concrete after hardening. 12. A method for greening existing concrete with moss, comprising spraying diatomaceous earth-containing ready-mixed concrete of 3 or 5 onto the existing concrete, and promoting the growth and growth of moss using the diatomaceous earth-containing ready-mixed concrete after hardening.

[0008] By spraying the diatomaceous earth-containing ready-mix concrete of the present invention onto concrete slopes and the like, it becomes possible to promote the attachment and growth of moss plants, thereby enabling the greening of concrete slopes and the like.

[0009] The photograph shows the appearance of diatomaceous earth-containing ready-mixed concrete of the present invention sprayed onto an existing concrete slab using the dry spraying method (the panel on the right side of the photograph). Note that A represents the appearance when calcined diatomaceous earth, B represents dried diatomaceous earth, and C represents flux-calcined diatomaceous earth. The photograph shows the appearance of diatomaceous earth-containing ready-mixed concrete containing moss sprayed onto an existing concrete slab using the dry spraying method (the long vertical panel on the left side of the photograph). Note that A represents the appearance when calcined diatomaceous earth, B represents dried diatomaceous earth, and C represents flux-calcined diatomaceous earth. The photograph shows the appearance of diatomaceous earth-containing ready-mixed concrete of the present invention mixed with a thickener and gelling agent, applied to an existing concrete block using the wet spraying method, six months later. The photograph shows the appearance of diatomaceous earth-containing ready-mixed concrete containing moss applied to a steel plate and left outdoors for 10 months. Moss had grown. This shows the appearance of Siberian moss adhered to the diatomaceous earth-containing concrete of the present invention after hardening and mixing with a thickener and gelling agent, using an adhesive composition.

[0010] The present invention will be described in detail below. 1. Regarding the Diatomaceous Earth-Containing Ready-Mixed Concrete of the Present Invention The diatomaceous earth-containing ready-mixed concrete of the present invention is composed of diatomaceous earth, cement, and water, which are the main components. Furthermore, thickeners, gelling agents, mosses, etc. may also be added. Admixtures and additives may also be added. Note that ready-mixed concrete refers to concrete before hardening. (1) Regarding the Mixing Ratio of Each Component: The mixing ratio of diatomaceous earth to cement, by weight, is preferably 5:95 to 70:30, and more preferably 10:90 to 50:50. The amount of water mixed is adjusted based on the slope and hardness of the construction surface to ensure that the concrete adheres to the construction surface and minimizes splashback. In terms of the water-cement ratio, the water-cement ratio is approximately 30 to 65% by weight. Regarding the ratio of diatomaceous earth to cement, a higher ratio of diatomaceous earth increases water absorption, but a lower ratio of cement reduces strength, such as making the cement more susceptible to cracking. Therefore, the ratio of diatomaceous earth to cement must be appropriately balanced in terms of water absorption and strength. Furthermore, the component ratios and amounts in ready-mix concrete are considered to be the mixing ratios and amounts of the raw materials at the time of mixing. The concrete of the present invention is intended to be sprayed onto existing concrete slopes or bridge piers, and it only needs to be sprayed onto these to fix them in place. Since it is not a sprayed concrete for structures, such as preventing rock collapses, it does not require structural strength, and the components do not need to be strong enough to support such a structure. (2) Diatomaceous Earth: Diatomaceous earth may be dried, calcined, or flux-calcined, but calcined and / or flux-calcined products are preferred, and calcined products are even more preferred. Calcined products have higher water retention than others, and flux-calcined products are less likely to crack when made into concrete. It has also been suggested that calcined products have a higher affinity with bryophytes than others. (3) Cement The cement may be any of Portland cement, polymer cement, blended cement, special cement, and ecocement, but Portland cement and polymer cement are more preferred. (4) Admixtures In addition to diatomaceous earth and cement, admixtures such as quick-setting agents and colorants may also be mixed.(5) Promoting Moss Growth and Evolution: To accelerate the formation of moss colonies, moss plants need to photosynthesize. Because moss plants cease photosynthesis when dry, efficient photosynthesis requires a cultivation site that can constantly release water vapor and maintain humidity. To create such a cultivation site, concrete can be mixed with crushed stone containing highly absorbent and water-retentive materials. Among these materials, diatomaceous earth, whose main chemical composition is silicon dioxide, similar to that of ordinary crushed stone, and which is believed to have a high affinity with moss plants, was used. In fact, the hardened diatomaceous earth-containing concrete of the present invention exhibits surprisingly high water absorption, making it suitable for promoting the growth and evolution of moss plants. Furthermore, it is believed to have a high affinity with moss plants, and experiments have demonstrated that moss plants can grow and evolve. While wet cement has a high pH, ​​the addition of a large amount of diatomaceous earth enhances humidity retention, and the concrete surface tends to neutralize and lower its pH as it hardens, making it suitable for the growth and evolution of moss plants.

[0011] 2. Techniques for Mixing Diatomaceous Earth (1) Dry Spraying Method The diatomaceous earth-containing concrete of the present invention is concrete that is sprayed onto concrete slopes and the like. There are two methods for spraying concrete: dry and wet. The wet method, in which the diatomaceous earth is mixed with water in a mixer or similar device beforehand, can lead to the problem of the wet diatomaceous earth particles adhering strongly to each other, making it difficult to mix with cement. The dry spraying method, in which the diatomaceous earth is mixed with water before spraying, is more preferable because it avoids this problem and allows the diatomaceous earth to be dispersed in the cement. By mixing the diatomaceous earth and cement without adding water, known as a dry mix, the diatomaceous earth disperses in the cement, and adding water before spraying can prevent the diatomaceous earth particles from adhering to each other. (2) Mixing of Thickeners and Gelling Agents (I) As already mentioned, the wet spraying method, in which diatomaceous earth is mixed with water and kneaded in advance, suffers from the problem of strong adhesion between diatomaceous earth particles, preventing the diatomaceous earth from dispersing in the cement and making mixing difficult. However, surprisingly, adding a thickener or gelling agent prevents the diatomaceous earth particles from adhering to each other and increases fluidity, solving this problem. This is thought to be because it reduces friction, making it difficult for the protrusions of diatomaceous earth particles to interlock. It also reduces cracking and surface peeling that occur when the amount of diatomaceous earth mixed exceeds 50% by weight during the preparation of diatomaceous earth-containing concrete. Thus, wet spraying is possible using diatomaceous earth-containing ready-mix concrete mixed with a thickener or gelling agent. (II) The thickener or gelling agent of the present invention is a compound that has a thickening effect, a gelling effect, or both. For example, cellulose ether is a thickener, while carrageenan and alginate are both thickeners and gelling agents, but thickeners / gelling agents include both. Thickeners and gelling agents are classified based on their functions, and because the thickening and gelling functions overlap to some extent, it is not always appropriate to strictly separate them. Therefore, we have decided to collectively define thickeners and gelling agents as thickeners / gelling agents. It is preferable to use thickeners / gelling agents that do not inhibit the growth of moss plants. It is even more preferable for thickeners and gelling agents to be derived from natural products or chemically modified natural products.Examples of thickeners and gelling agents of the present invention include cellulose ether, xanthan gum, carrageenan, alginate, etc. Cellulose ether is a general term for derivatives in which other atomic groups are bonded to the hydroxyl groups of cellulose via ether bonds, such as methylcellulose, ethylcellulose, ethylmethylcellulose, carboxymethylcellulose, carboxyethylcellulose, hydroxyethylcellulose, hydroxypropylcellulose, benzylcellulose, tritylcellulose, cyanoethylcellulose, and aminoethylcellulose. Methylcellulose, hydroxypropylmethylcellulose, and hydroxyethylmethylcellulose (including those surface-treated with glyoxal) are more preferred. Xanthan gum is a compound produced by fermenting starch such as corn, and is used as a thickener for foods. Carrageenan is a polysaccharide extracted from red algae and comes in three types: κ (kappa), ι (iota), and λ (lambda). The carrageenan of the present invention may be any type or a mixture of these. Alginate is a polysaccharide found in brown algae, etc. Alginates include various alginates such as sodium alginate, potassium alginate, and ammonium alginate. The thickener / gelling agent of the present invention may be a mixture of different thickeners / gelling agents. (III) The thickener / gelling agent is preferably present in an amount of 0.25 to 10 wt. % of the total of cement and diatomaceous earth and other components other than water, and more preferably 0.5 to 5 wt. In this case, the weight percentage refers to the total value of different thickeners / gelling agents in a mixture. (IV) The thickener / gelling agent may be mixed with diatomaceous earth and then mixed with other ingredients, or all ingredients other than water may be added and mixed, followed by the addition of water. (V) The diatomaceous earth-containing ready-mix concrete prepared in this manner can be sprayed onto the construction surface using a wet spraying method.

[0012] 3. Regarding the Inclusion of Mosses: (1) Considering the effort required for application, it would be preferable to premix mosses with diatomaceous earth concrete for moss planting. However, wet cement is highly alkaline, and direct contact of mosses with it would result in the death of most mosses. We discovered that a solution to prevent this death is to precoat the mosses with a thickener / gelling agent to prevent direct contact with the cement. The coating is achieved by mixing the mosses with an aqueous solution of the thickener / gelling agent so that they become entangled. (2) The mosses to be mixed include moss gametophytes, moss fragments, moss protonemata, spores, and moss gemmae. Furthermore, mosses of the genus Sunagoke, which are often used for greening structures, are even more preferable. Examples of Sunagoke include Ezo Sunagoke, Reticulata Sunagoke, and Long-Easy Sunagoke. The amount of moss mixed is preferably 1 to 10% by weight based on the weight of the ready-mix concrete. The thickener / gelling agent mixed with the moss is the same as that shown in (2)(II). It is dissolved in water and used. The thickener / gelling agent solution mixed with the moss is preferably a 0.25 to 30% by weight aqueous solution, and even more preferably a 5 to 10% by weight aqueous solution. Among thickeners / gelling agents, potassium alginate is particularly preferred. When potassium alginate is used, the calcium in the cement reacts with the alginic acid to form a strong gel coating, protecting the moss, using the same principle as artificial salmon roe. This allows more moss to survive until the cement hardens and becomes harmless. The potassium released in this reaction serves as fertilizer for the moss and promotes its growth. (3) If you are in a hurry to green the area without considering the time and effort required for construction, you can fix the moss gametophytes to the surface of the sprayed diatomaceous earth concrete for moss greening with a thickener such as cellulose ether or a gelling agent such as carrageenan, or attach the moss plants integrated with a net, etc. Another method is to attach and fix diatomaceous earth in which moss plants have been grown, mixed with a thickener such as cellulose ether, a gelling agent such as carrageenan, or bentonite, etc.

[0013] 4. Waterproofing of edges In cold regions, water-absorbing concrete expands when frozen, which can cause the concrete to peel off, especially around the edges of the sprayed concrete. Waterproofing the edges can be used to prevent this.

[0014] Example 1: Spraying by Dry Spraying Method (1) Experimental Materials and Methods: A. Calcined diatomaceous earth, B. Dried diatomaceous earth, C. Flux-calcined diatomaceous earth, and Portland cement were used for the diatomaceous earth. 10 kg of diatomaceous earth and 10 kg of cement were dry mixed and loaded into a spraying machine. This mixture was mixed with water supplied from a separate route just before the spraying nozzle and sprayed onto the concrete slab. The amount of water was adjusted appropriately by the spraying worker to ensure the concrete adhered and minimized splashing. (2) Results: In all cases where diatomaceous earth was used, the sprayed concrete adhered to the concrete slab and could be sprayed without any problems. Furthermore, no cracks or surface peeling occurred after hardening (the slab on the right in Figure 1).

[0015] Example 2: Spraying of diatomaceous earth concrete containing sunagoke moss using the dry spraying method (1) Experimental materials and method: The experiment was carried out in the same manner as in Example 1. However, 100 g of sunagoke moss fragments were mixed with 500 mL of a 5 wt% aqueous potassium alginate solution, and after removing excess water with a paper towel, the mixture was mixed with the diatomaceous earth and cement. (2) Results: In all cases where diatomaceous earth was used, the sprayed concrete adhered to the concrete slab and could be sprayed without any problems. Furthermore, no cracks or surface peeling occurred after hardening (the vertical slab on the left in Figure 2).

[0016] Example 3: Mixing a thickener and gelling agent and applying ready-mixed diatomaceous earth concrete in a manner similar to wet spraying. (1) Experimental Materials and Methods: Calcined diatomaceous earth was used as the diatomaceous earth, and Portland cement was used as the cement. Methylcellulose was also used as the thickener and gelling agent. 250 g of diatomaceous earth, 250 g of Portland cement, and 15 g of methylcellulose were mixed, water was added until the mixture reached the appropriate viscosity, and the mixture was applied to the vertical surface of a concrete block. (2) Results: Concrete with the same composition as the sprayed concrete adhered to the concrete block and was applied without any problems. Furthermore, no cracks or surface peeling occurred after hardening. Furthermore, moss plants were confirmed to have sprouted approximately six months later (circled area in Figure 3).

[0017] Example 4 Application of diatomaceous earth-containing ready-mix concrete containing moss (1) Experimental materials and method In addition to the materials used in Example 3, 100 mL of a 5 wt% potassium alginate solution was mixed with 10 g of sunagoke moss fragments. This mixture was applied to an iron plate and left outdoors for 10 months. (2) Results The sunagoke moss contained in the diatomaceous earth-containing ready-mix concrete grew, covering the concrete surface (Figure 4).

[0018] Example 5 Fixation of Sunagoke Moss to Diatomaceous Earth-Containing Concrete (1) Experimental Materials and Methods Dried diatomaceous earth, calcined diatomaceous earth, and flux-calcined diatomaceous earth were used, and Portland cement was used as the cement. Furthermore, methylcellulose and κ-carrageenan were used as the adhesive composition for Sunagoke Moss. 250g of each diatomaceous earth, 250g of cement, and 15g of methylcellulose were mixed to form ready-mix concrete, which was then allowed to harden. 5g of methylcellulose, 5g of κ-carrageenan, and 500g of water were mixed to form an adhesive composition, and the adhesive composition was applied to the rhizoids of Sunagoke Moss on top of the hardened concrete to fix the Sunagoke Moss. (2) Results In all cases, Sunagoke Moss was able to adhere, and the attachment and growth of Sunagoke Moss was confirmed (Figure 5, upper left: flux-calcined diatomaceous earth, upper right: dry diatomaceous earth, bottom two: calcined diatomaceous earth).

[0019] Example 6: Study of Water Absorption (1) Experimental Materials and Methods: Various types of diatomaceous earth were mixed with Portland cement to prepare diatomaceous earth-containing concrete with diatomaceous earth contents of 30%, 50%, and 70% by weight. The weights of the concrete samples were compared between dry and water-absorbed states to compare their water absorption. (2) Results: The experimental results showed that calcined diatomaceous earth absorbed the most water, followed by dried diatomaceous earth and flux-calcined diatomaceous earth. Furthermore, increasing the diatomaceous earth content from 30% to 50% by weight and from 50% to 70% by weight only increased the water content by approximately 10% by weight (Table 1).

[0020]

[0021] Example 7: Study on the Relationship between Diatomaceous Earth Concentration and Durability of Diatomaceous Earth-Containing Concrete (1) Experimental Materials and Methods: Diatomaceous earth-containing concrete was prepared as in Example 6 and placed outdoors on a steep slope. (2) Results and Discussion: Even when placed outdoors on a steep slope, 30% and 50% diatomaceous earth samples showed no or only minor cracking or surface peeling. Only when exposed to heavy rain did the surface of 70% diatomaceous earth-containing concrete collapse (Table 2). Increasing the diatomaceous earth content does not improve water absorption proportionally. Considering the results of Example 6, a 30% diatomaceous earth concentration is recommended for installation on steep slopes, while 50% diatomaceous earth is suitable for gentle slopes. 70% diatomaceous earth can also be used on nearly level surfaces.

[0022]

[0023] The ready-mixed concrete containing diatomaceous earth of the present invention makes it possible to easily green existing concrete slopes and concrete bridge piers with moss plants, making it useful in the civil engineering and construction industries.

Claims

1. Diatomaceous earth-containing ready-mix concrete consisting of diatomaceous earth, cement, and water, with a weight ratio of diatomaceous earth to cement of 5:95 to 70:

30.

2. A method of spraying diatomaceous earth-containing ready-mixed concrete, which is made of diatomaceous earth, cement, and water, onto a construction surface, in which the diatomaceous earth and cement are mixed without adding water, and water is added when spraying to form ready-mixed concrete, which is then sprayed.

3. Diatomaceous earth-containing ready-mix concrete consisting of diatomaceous earth, cement, and water, containing 0.25 to 10% by weight of a thickener / gelling agent relative to the total weight of the ingredients other than water.

4. The diatomaceous earth-containing ready-mix concrete of claim 3, wherein the thickening agent / gelling agent is one of cellulose ether, carrageenan, xanthan gum, and alginate, or a mixture of two or more of these.

5. Diatomaceous earth-containing ready-mix concrete consisting of diatomaceous earth, cement, and water, containing a mixture of moss plants and 0.25 to 30% by weight of an aqueous solution of a thickener and gelling agent.

6. The diatomaceous earth-containing ready-mix concrete of claim 5, wherein the thickening agent / gelling agent is one of cellulose ether, carrageenan, xanthan gum, and alginate, or a mixture of two or more of these.

7. Concrete obtained by hardening the ready-mix concrete of any one of claims 1, 3 to 6.

8. Concrete in which the ready-mix concrete of any one of claims 1, 3 to 6 has hardened on top of existing concrete.

9. The concrete of claim 8, the edges of which are waterproofed.

10. A ready-mixed concrete containing diatomaceous earth according to any one of claims 1, 3 and 5, for promoting the growth and attachment of moss plants.

11. A method for greening existing concrete with moss plants, comprising spraying diatomaceous earth-containing ready-mixed concrete onto the existing concrete using the spraying method of claim 2, and promoting the attachment and growth of moss plants using the diatomaceous earth-containing ready-mixed concrete after hardening.

12. A method for greening existing concrete with moss plants, comprising spraying the diatomaceous earth-containing ready-mixed concrete of claim 3 or 5 onto the existing concrete, and promoting the attachment and growth of moss plants using the diatomaceous earth-containing ready-mixed concrete after hardening.

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