JP5366369B2 - Soil-based solidified material and pavement method for soil-based solidified material - Google Patents

Description

  The present invention relates to a soil-based solidified material and a paving method thereof.

  On roads and sidewalks, not only can ridges and dents occur due to traffic, making it impossible to drive comfortably and walk safely, but also it is possible to puddle on ridges and dents when it rains, so asphalt paving on the roads It was. However, asphalt pavement has poor water permeability and water pools. In addition, the pavement surface easily accumulates heat in summer, which causes a heat island phenomenon. Therefore, water-permeable asphalt pavement with improved water permeability of asphalt and water-retentive asphalt pavement with water retention are spreading. It becomes a landscape, and the road surface is hard and the repulsion is strong. Therefore, in recent years, pavement that is closer to nature and more friendly to people is being adopted, such as Masagochi pavement.

  In soil-based pavements such as mango soil pavement, natural soil is used and mixed with a solidifying material to give the soil strength. Conventionally, cement-based solidified materials using cement as a main raw material and lime-based materials using lime as a main raw material have been mainstream as the solidifying materials, but recently solidified materials using slag are also seen.

  Patent Document 1 discloses that soil-based solidified material does not include a porous material, but includes slaked lime and slag in a soil-based pavement in which soil and solidified material are mixed and spread on a pavement and leveled, and then rolled and cured. doing. The mixed soil containing slaked lime and slag solidifies at room temperature, solidifies with strength and hardness not as low as those made of conventional asphalt and not as low as those made of natural soil only. . According to Example 1, 100 parts by mass of slaked lime, 50 parts by mass of clay, and 50 parts by mass of blast furnace slag were mixed into an earth-based pavement solidifying material. Ensures water permeability.

JP 2004-52536 A

  In soil-based pavements such as mango sand pavement, natural soil is used and mixed with a solidifying material to increase the strength of the soil and ensure water permeability. As this solidifying material, cement or slag mixed with a stimulant such as slaked lime was used.

  INDUSTRIAL APPLICABILITY The present invention can inexpensively provide a soil-based solidifying material that can be mixed with low-strength soil or soil with poor water permeability to improve the strength and water-permeable soil, and using this soil-based solidifying material, The purpose is to provide a method for paving the surface layer of roads, sidewalks, playgrounds and stadiums.

  Since the present invention can use calcium aluminate-based slag itself as a solidifying material, it is possible to provide a soil-based solidifying material at a low cost with a small amount of mixture, and roads and sidewalks using a soil-based solidifying material, It provides a method for paving the surface layer of athletic fields and stadiums.

That is, the gist of the present invention is as follows.
(1) A soil-based solidified material in which calcium aluminate slag having hydraulic properties is mixed with soil, and the calcium aluminate slag having hydraulic properties is Al ₂ O ₃ : 25 to 45% by mass ( CaO + CaF ₂ ) / Al ₂ O ₃ : 1.1 to 2.0, CaF ₂ : 2 to 6%.
(2) In a test body in which the soil-based solidified material was molded according to JIS A 1216 (soil uniaxial compression test method) with 10% water added and mixed, the uniaxial compressive strength at a material age of 7 days was 5 N / The earth-based solidified material as described in (1) above, which is mm ² or more.
(3) above (1) providing a soil type hardening material according to or (2), leveling paved by adding water to the soil type hardening material, also the water after leveling spread the soil type hardening material Additionally compaction, or soil-based pavement method wherein compaction isosamples adding water after leveling paved by adding water to the soil type hardening material.

In the present invention, having hydraulic property means a property of forming a hydrate by a chemical reaction with water, condensing and curing. Further, in the present invention, calcium aluminate-based slag is steel slag produced as a by-product in the steel manufacturing process, and is a high-alumina slag produced when aluminum is used as a deoxidizer for molten steel. The slag is characterized in that the component is calcium aluminate such as 12CaO · 7Al ₂ O ₃ , 11CaO · 7Al ₂ O ₃ · CaF ₂ , 3CaO · Al ₂ O ₃ , CaO · Al ₂ O ₃ .

  INDUSTRIAL APPLICABILITY The present invention can inexpensively provide a soil-based solidifying material that can be mixed with low-strength soil or soil with poor water permeability to improve the strength and water-permeable soil, and using this soil-based solidifying material, It provides a method for paving the surface layers of roads, sidewalks, playgrounds, and stadiums.

The soil-based solidified material of the present invention uses calcium aluminate-based slag having hydraulic properties. The reason for using calcium aluminate slag is that a component range having particularly strong hydraulic properties in steel slag exists in calcium aluminate slag. Most of the general steel slag is calcium silicate slag, and these have strength (uniaxial compressive strength) when the basicity, which is the content ratio of calcium oxide and silicon dioxide in the slag component, is high. It was necessary to improve the strength by mixing gypsum or the like, or by making the slag as fine as the cement (for example, a specific surface area of about 2,500 cm ² / g). On the other hand, calcium aluminate-based slag is economical because slag can be used as it is by selecting steel slag produced as a by-product in the iron production process into a specific component range. Since the slag has hydraulic properties, it is hardened and emits strength when mixed with soil and added with water. A mixture obtained by mixing soil and the slag in an appropriate amount in accordance with the characteristics of the soil can be provided as a soil-based solidifying material, and can be paved by simply adding water.

  Here, the soil is what is called true sand soil, which is made by weathering granite that is often harvested in Japan, and is naturally collected soil. These are often used for sidewalks, parks, grounds, on-site gardens and parking lots. In addition, these collected soils are mixed with sand, crushed stone, slag aggregate, tiles, glass, wood chips, rubber, etc. Contains mixed soil.

  The present invention uses a soil-based solidified material in which soil and calcium aluminate-based slag are mixed in an appropriate amount in accordance with the characteristics of the soil in advance, or by mixing calcium aluminate-based slag in the soil with a soil-based solidified material. None, can be paved by adding water, leveling, rolling and solidifying properly. When mixing a soil-based solidifying material and water, if there is a concrete mixer, it can be easily mixed with water uniformly. However, if there is no mixer, it is difficult to mix manually. After leveling, the water can be uniformly sprinkled from the surface, water can be added, and then the floor can be solidified and paved.

  When paving a heavy object such as a vehicle, it is better to lay down a subgrade material such as crushed stone under the surface pavement. The thickness of the lower roadbed and the thickness of the surface pavement are determined according to the application. For example, in a sidewalk, the roadbed thickness of the lower layer may be 50 to 100 mm and then paved with about 50 mm of earth-based solidified material on the surface layer.

  The mixing ratio of soil and calcium aluminate slag can be determined in consideration of the intended use and the characteristics of the soil. When the strength of the road surface that does not burden the foot such as a sidewalk is sufficient, or when the road surface strength is required in a parking lot or the like, there is an appropriate strength depending on the application, so it is desirable to determine the composition according to the strength. In addition, since the quality varies depending on the production area of the soil, the strength varies even if calcium aluminate-based slag of the same proportion is mixed depending on the characteristics of the soil used. Therefore, it is necessary to perform a blending test in advance to determine the blending of soil and calcium aluminate-based slag that is suitable for strength and the amount of added water.

In the melting of molten steel in the steel manufacturing process, when aluminum is used as a deoxidizer for molten steel, Al ₂ O ₃ is generated in the slag. The composition of the slag including Al ₂ O ₃ is, for example, calcium aluminate containing CaO: 45%, SiO ₂ : 4%, Al ₂ O ₃ : 30%, and other MgO in melting of stainless steel. System slag is formed. These slag compositions vary greatly depending on operating conditions such as the melting method. Depending on conditions, fluorite containing a large amount of calcium fluoride (CaF ₂ ) may be used. In the present invention, the calcium aluminate slag thus produced can be used.

The calcium aluminate-based slag having hydraulic properties of the present invention contains, as a first component composition, Al ₂ O ₃ : 20 to 40%, CaO: 30 to 60%, SiO ₂ : 3 to 15% by mass%. It is preferable if it is. Such calcium aluminate-based slag can be slag generated in a melting step deoxidized using aluminum.

The present inventor has found that a calcium aluminate-based slag having the above composition has strong hydraulic properties, and there is a component system having hydraulic properties equal to or higher than those of conventional ordinary Portland cement. In this composition range, 12CaO · 7Al ₂ O ₃ (hereinafter also referred to as “C ₁₂ A ₇ ”) is mainly generated as the mineral composition of the steel slag, and 3CaO · SiO ₂ (hereinafter also referred to as “C ₃ S”). .) Is generated. When these are mixed with water, the hydration reaction is promoted, resulting in fast reaction rate and strong hydraulic strength.

In the first composition of the present invention, for Al ₂ O ₃ component, Al ₂ O ₃ is insufficient Al ₂ O ₃ for producing a C ₁₂ A ₇ is less than 20%, C ₃ is 40 percent The amount of S produced is insufficient. Therefore, the range of Al ₂ O ₃ is set to 20 to 40%. As for the CaO component, when CaO is less than 30%, CaO for producing C ₁₂ A ₇ is insufficient, and when it exceeds 60%, the amount of C ₁₂ A ₇ produced is insufficient. Therefore, the range of CaO is set to 30 to 60%. The SiO ₂ component, SiO ₂ is insufficient SiO ₂ to generate the C ₃ S is less than 3%, insufficient production of C ₁₂ A ₇ is 15 percent. Therefore, the SiO ₂ range is set to 3 to 15%.

In these slag compositions, CaO / Al ₂ O ₃ is 1-2, and CaO / SiO ₂ is 10 or less. In the region where CaO / Al ₂ O ₃ is smaller than 1, C ₃ S is not generated at all regardless of CaO / SiO _2, and in the region where CaO / Al ₂ O ₃ is larger than ₂ , C ₁₂ A regardless of CaO / SiO _{2. 7} does not generate. In the region where CaO / SiO ₂ is 10 or more, C ₃ S is not generated at all. C ₁₂ A ₇ and C ₃ S are most produced in a region where CaO / Al ₂ O ₃ is 1 to 2 and CaO / SiO ₂ is 10 or less. When C ₃ S is generated in the slag, the slag collapses due to the transformation of the mineral during the cooling of the slag and is pulverized to a fine powder of about 75 μm. This powdered slag has a hydraulic property equivalent to or better than ordinary Portland cement, so it does not require a slag grinding step, and if necessary, sifts and aligns the particle size to provide a hydraulic calcium aluminate. Can be provided as system slag. Moreover, since slag does not perform processes, such as water cooling, it does not contain a water | moisture content at all.

MgO and other components in the slag composition are included depending on the operating conditions such as the melting method, but within the scope of the present invention where 20% or more of Al ₂ O ₃ is included, the mineral composition of the calcium aluminate slag by MgO and other components There is no big change and the effect on the properties of slag is small.

The calcium aluminate-based slag having hydraulic properties of the present invention has, as a second component composition, Al ₂ O ₃ : 25 to 45%, (CaO + CaF ₂ ) / Al ₂ O ₃ : 1.1 to _2. % by mass. 0, CaF ₂ : It is preferable to contain _{2 to} 6%. Such calcium aluminate-based slag can be slag generated in a melting step deoxidized using aluminum.

Calcium aluminate slag generated when fluorite is used as a smelting agent in the melting of steel and aluminum deoxidation is performed, and the slag hydraulic properties are evaluated. It has been found that there is a component system that has hydraulic properties and has hydraulic properties equivalent to or higher than those of conventional ordinary Portland cement. Also, When checking its mineral composition for the slag to exert hydraulic, for slag of the above composition range (hereinafter also referred to as "C ₁₁ A ₇ · CaF _{2".) 11CaO · 7Al 2 O 3} · CaF 2 and CaO It became clear that it contains. When these are kneaded with water, the hydration reaction is promoted, resulting in a fast reaction rate and strong hydraulic strength.

In the second composition of the present invention, for Al ₂ O ₃ component, Al ₂ O ₃ is insufficient Al ₂ O ₃ for producing a C ₁₁ A ₇ · CaF ₂ is less than 25%, than 45% Then, the amount of CaO produced is insufficient. Therefore, the range of Al ₂ O ₃ is set to 25 to 45%.

As for the ratio of CaO + CaF ₂ component to Al ₂ O ₃ component (CaO + CaF ₂ ) / Al ₂ O ₃ , the required CaO is insufficient when the ratio is less than 1.1, and the CaO increases when the ratio exceeds 2.0. ₁₁ a ₇ · CaF ₂ is small, can not be sufficiently demonstrate the hydraulic action. Therefore, (CaO + CaF ₂ ) / Al ₂ O ₃ was set to 1.1 to 2.0.

When CaF ₂ is less than 2%, C ₁₁ A ₇ · CaF ₂ is small and mixed with C ₁₂ A _7, and hydraulic properties cannot be exhibited. On the other hand, if CaF ₂ exceeds 6%, excess CaF ₂ is contained, which is not preferable. Therefore, the composition range of CaF ₂ is set to 2 to 6%.

The calcium aluminate-based slag contains CaO, Al ₂ O ₃ , CaF ₂ as well as SiO ₂ , MgO, etc. as components, but in the component composition containing the second CaF ₂ of the present invention, Al ₂ When the total amount of O ₃ , CaO, and CaF ₂ components is 75% or more, hydraulic properties can be sufficiently exhibited.

  EXAMPLES Hereinafter, although this invention is demonstrated concretely based on an Example, this invention is not limited to a following example.

  About the calcium aluminate-type slag which has the 1st, 2nd component composition of this invention, the relationship between a component composition and hydraulic property was evaluated.

As a hydraulic evaluation method, 25% of water was added to the hydraulic composition and kneaded, and uniaxial compressive strength was measured according to JIS A 1108 (concrete compressive strength test method). In order to grasp the original strength of the hydraulic composition, it was evaluated without adding any aggregates. If the uniaxial compressive strength was 10 N / mm ² or more, it was judged to have a function as a solidifying material.

  Table 1 shows slag having the first component composition of the present invention, and Table 2 shows slag having the second component composition.

As a result of confirming the mineral composition of the slags of Invention Examples 1 to 6 in Table 1, all were mainly C ₁₂ A _{7 and} the presence of C ₃ S could be confirmed. On the other hand, in Comparative Example 1, the presence of C ₃ S is so small that the presence of C ₃ S cannot be confirmed. In Comparative Example 2, CaO—SiO ₂ -based slag is mainly used, and the presence of C ₁₂ A ₇ is small. In Comparative Example 3, the presence of C ₁₂ A ₇ cannot be confirmed.

In Invention Examples 1 to 6 in Table 1, since the component range is within the range of the present invention, the uniaxial compressive strength was a good value. In particular, Examples 4 to 6 of the present invention satisfied preferable ranges of CaO / Al ₂ O ₃ of 1 to 2 and CaO / SiO ₂ of 10 or less, and were able to realize good uniaxial compressive strength. On the other hand, Comparative Examples 1 to 3 were all unsuitable because of their low uniaxial compression strength.

As a result of confirming the mineral composition of the slags of Invention Examples 1 to 4 in Table 2, all were mainly C ₁₁ A ₇ CaF _{2 and} the presence of CaO could be confirmed. On the other hand, in Comparative Example 1 C ₁₁ A ₇ CaF ₂ is small, Comparative Example 2, CaO many, C ₁₁ A ₇ CaF ₂ is small. In Comparative Example 3, the presence of CaO cannot be confirmed.

  In Invention Examples 1 to 4 in Table 2, the component range was within the range of the present invention, so the uniaxial compressive strength was a good value. On the other hand, Comparative Examples 1 to 3 were all unsuitable because of their low uniaxial compressive strength.

  The calcium aluminate-based slag having hydraulic properties of the present invention shown in Tables 1 and 2 and the comparative examples are solidified material No. Table 3 shows examples of soil-based solidified materials using these solidified materials and pavement using the soil-based solidified materials.

( Reference Example 1)
After adjusting the particle size by sieving the pure sandy soil at 13 mm, calcium was obtained by sieving the adjusted pure sandy soil 100% by weight after drying at 110 ° C. to remove moisture and Reference Example 6 (solidified material No. F) in Table 1 with 2 mm. An earth-based solidified material in which 50% by mass of aluminate-based slag was uniformly mixed was produced. A test body in which 10% of water was added and mixed with this soil-based solidified material according to JIS A 1216 (method for uniaxial compression test of soil) was molded, and the uniaxial compressive strength at the age of 7 days was measured. Uniaxial compressive strength was able to sufficiently secure a 5N / mm ² or more necessary 14.3N / mm ² and soil-based pavement. Example Example 1 in Table 3 was prepared and mixed under the same conditions as described above using the same kind of soil as Reference Example 1 described above and Comparative Example 1 (solidified No. G) shown in Table 1. As a result of comparing the uniaxial compressive strength of the materials, it is as low as 2.3 N / mm ^2, and the superiority of Reference Example 1 of the present invention can be clearly evaluated.

  Mainland-based solidification materials can be constructed simply by adding water to a site that contains a mixture of soil and calcium aluminate-based slag. It is suitable for providing materials to be paved at a relatively small construction site.

( Reference Example 2)
The sidewalk in the park was asphalt paved, but in order to make use of the natural landscape and to make it a friendly sidewalk, we remodeled it into an earth-based pavement. After removing asphalt, JIS A 5001 (road crushed stone) C-30 crushed stone was laid and solidified for 100 mm, and soil-based solidified material mixed with soil and calcium aluminate slag was laid and solidified for 50 mm. Earth-based paving was performed. The soil uses pure sand, and the calcium aluminate slag uses slag of the same component as Reference Example 4 (solidified No. D) in Table 1, and 20% of calcium aluminate slag is 100% by mass of pure sand. It mix | blended in the ratio of the mass%. After 5 to 10% of water was added to the mixer truck at the construction site and mixed uniformly, the mixture was spread on the pavement and rolled to a thickness of 50 mm with a road roller. After construction, water was sprayed as needed while observing the dryness of the weather, and the surface was covered with a waterproof sheet and cured for 5 days. The next day it was solid enough to walk, but was cured until it was more stable. The uniaxial compressive strength (JIS A 1216) after 7 days of this earth-based pavement is 6.8 N / mm ² , and the hydraulic conductivity (JIS A 1218) is 10-4 to 10-5. The resulting pavement was well drained. At the same time, it was finished in a pavement with a beautiful landscape in harmony with nature.

In Example Comparison 2, using Comparative Example 2 (solidified material No. O) shown in Table 2 as a comparison, the uniaxial compressive strength investigated under exactly the same conditions and method as Example 2 described above was 1.5 N / Mm ² and the required strength could not be obtained, confirming the superiority of the present invention.

(Example 3)
Using clay soil on the natural road, pavement was performed by blending 100% by mass of soil and 20% by mass of solidifying material. As the solidified material of Example 3, Example 1 (solidified material No. J) of the present invention shown in Table 2 was used, and comparison of the examples was performed using Comparative Example 3 (solidified material No. P) of Table 2. The uniaxial compressive strength of the comparative example is as low as 1.9 N / mm ² , which is not suitable because a dent or the like is easily generated on the road surface. In the present invention, an appropriate strength of 7.8 N / mm ² with no burden on the foot was obtained.

Example 4
The parking lot was paved with a soil-based solidified material mixed with soil and hydraulic calcium aluminate-based slag. The construction site of the parking lot was dug down 200 mm, and C-40 crushed stone was laid down 150 mm on the lower roadbed, and then 50 mm of earth-based solidified material was laid down on the surface layer. As the soil-based solidified material, 40% by mass of calcium aluminate-based slag having the same composition (solidified material No. L) as that of the present invention 3 in Table 2 was used with respect to 100% by mass of sand sand. Recycled aggregate prepared by crushing roof tiles and adjusting the particle size to 5 to 13 mm was kneaded with 20% by mass, pigment and water. The soil-based solidified material kneaded at the construction site was leveled and then ground with a vibration roller. After the construction, the surface was covered with a waterproof sheet and cured for 5 days. The uniaxial compressive strength after 7 days of this soil-based pavement is 11 to 13 N / mm ² , and the water permeability is 10 −4 to 10 −5. Sufficient strength is obtained as a parking lot, and the pavement has good drainage. Obtained. At the same time, the recycled aggregates and pigments resulted in a varied finish.

( Reference Example 5)
Pavement was performed using a soil-based solidified material in which ground and hydraulic calcium aluminate-based slag were mixed in the ground. The ground was dug 200 mm, and after crushing crushed stones of 40 mm or less to the lower ground layer by 100 mm, 50 mm of earth-based solidified material was spread on the surface layer. The soil-based solidified material is a mixture of 30% by mass of calcium aluminate-based slag and 10% by mass of silica sand, which are the same components as in Reference Example 3 (solidified material No. C) in Table 1 with respect to 100% by mass of sandy sand. Used and kneaded with water. After laying and leveling the soil-based solidified material kneaded at the construction site, it was spread with a road roller. After the construction, the surface was covered with a waterproof sheet and cured for 5 days. The uniaxial compressive strength after 7 days of this earth-based pavement is 8.6 N / mm ² , and the water permeability is 10-3 to 10-4. By adding 10% of sand, the strength increases and drainage Good ground pavement was obtained.

(Example 6)
Pavement was carried out using soil-based solidified material mixed with soil and hydraulic calcium aluminate-based slag. The soil-based solidified material contains 20% by mass of calcium aluminate-based slag having the same composition as that of the present invention 4 (solidified material No. M) in Table 2 and 100% by mass of sand sand, and 20% by mass of crushed stone of 13 mm or less. Then, water was added and kneaded. The soil-based solidified material kneaded at the construction site was leveled 100 mm, and then ground with a road roller. After the construction, the surface was covered with a waterproof sheet and cured for 5 days. The uniaxial compressive strength after 7 days of this earth-based pavement was 9.8 N / mm ² and a sufficient strength was obtained.

Claims (3)

A soil-based solidified material in which calcium aluminate slag having hydraulic properties is mixed with soil, and calcium aluminate-based slag having hydraulic properties is Al ₂ O ₃ : 25 to 45% by mass%, (CaO + CaF ₂ ) / Al ₂ O ₃ : 1.1 to 2.0, CaF ₂ : 2 to 6%. In a test body in which the soil-based solidified material was molded by adding and mixing 10% of water in accordance with JIS A 1216 (soil uniaxial compression test method), the uniaxial compressive strength at the age of 7 days was 5 N / mm ² or more. The earth-based solidifying material according to claim 1, wherein: Prepare the soil type hardening material according to claim 1 or 2, leveling spread by adding water to the soil type hardening material, or compacted by adding water after leveling spread the soil type hardening material, or soil type pavement method wherein compaction isosamples adding water after leveling paved by adding water to the soil type hardening material.