JP2011006299A - Permeable structural material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a permeable structural material for constructing a permeable base, the material having high strength, high permeability, high productivity, and high quality stability.SOLUTION: The permeable structural material includes granulated blastfurnace slag and an aggregate which has a particle size of 5 mm or less and does not contain the granulated blastfurnace slag, wherein the content of the aggregate is 40 mass% or more and the uniformity coefficient of the permeable structural material is 6.73 or less. The aggregate preferably include one or more selected from the group consisting of steel slag, waste brick, waste concrete, crushed stones, gravel, cobble stones, and sand. The structural material is particularly preferably used as an artificial turf base material.

Description

  The present invention relates to a water permeable structure material in which blast furnace granulated slag and aggregate are mixed.

  In recent years, as urbanization has progressed, the asphalt area on the ground surface has increased and the amount of rainfall permeation from the ground surface to the ground has decreased, which has contributed to groundwater depletion and the heat island phenomenon. As a countermeasure, to allow an increase in the amount of penetrating the ground surface rainfall paved into the ground, the adoption of paving material and roadbed material having a water permeability functions has been increasing.

  A general water-permeable structure material has a single-grain structure for the roadbed material in order to increase water permeability, and a water-permeable structure material using cement paste material in which cement-based material and water are kneaded into the pavement material to ensure the bearing capacity. Are known. Among them, steel slag used for road structural materials (roadbed and heated asphalt mixture) is stipulated in detail in JIS A5015, and the strength and water permeability can be increased within a range that conforms to this standard. Has been studied.

For example, Patent Document 1 discloses a water-permeable pavement obtained by mixing an aggregate and an epoxy resin, the porosity is 5 to 20% by volume, and the epoxy resin adhesive is a two-component room temperature. A water-permeable pavement that is a fast-curing type and has a viscosity at 20 ° C. of 800 to 1100 mPa / sec and a tensile strength of 320 kg / cm ² or more is disclosed.

  Patent Document 2 discloses a coarse product having a particle size of 25 to 5 mm such as a blast furnace slow-cooled slag by-produced in a blast furnace, a medium product having a particle size of 5 to 0 mm such as limestone, and a particle size of 2.5 to 5 such as blast furnace granulated slag. The aggregate particle size curve is mainly composed of at least one of 0 mm fine-grained products and 1 to 14% by weight of granulated blast furnace slag powder and 1 to 14% by weight of alkali stimulating material. Disclosed are water permeable compositions that fall within certain ranges.

  Patent Document 3 includes a water permeability which contains 50 to 90% by mass of blast furnace slow-cooled slag or steelmaking slag having a particle size of 5 to 40 mm and 50 to 10% by mass of granulated blast furnace slag having a particle size of 10 mm or less. A roadbed material is disclosed.

In Patent Document 4, blast furnace granulated slag having a specific surface area of 3000 to 4500 cm ² / g is described in Patent Document 4 as follows: by weight: blast furnace granulated slag having a maximum particle size of 5 mm or less that is not finely divided and having a small fine fraction Hydraulic pavement composed of 3 to 10% fine powder, maximum particle size of 15mm or less, 20 to 60% of converter slag with 15 to 20% passing through 0.4mm sieve and 4 to 10% passing through 0.074mm sieve A material is disclosed.

  In Patent Document 5, 20-30 parts by weight of sodium chloride, 20-30 parts by weight of magnesium chloride, 35-45 parts by weight of potassium chloride, 5-15 parts by weight of calcium chloride, and 4-8 of citric acid with respect to the granulated blast furnace slag. a mixture of parts by weight, and laid on the shaped base course shape, pavement construction method allowed to form a paving having water permeability is disclosed.

  Patent Document 6 includes a granular material such as crushed stone, gravel, or slag, and a base layer formed on a foundation ground and a polymer granular material formed of rubber chips or the like are bound with resin, and directly on the base layer. There is disclosed an artificial lawn pavement structure including an applied elastic layer having a thickness of 15 to 50 mm, and an artificial lawn containing sand laid on the elastic layer.

JP 2001-234503 A Japanese Patent Publication No.7-115909 JP 2005-139829 A Japanese Patent Publication No. 6-86318 Japanese Patent Publication No. 2-15504 No. 7-6165

However, the materials disclosed in these patent documents have the following problems.
Since the water-permeable pavement described in Patent Document 1 is a mixture of epoxy resin and aggregate, it is necessary to increase the porosity in order to increase water permeability, and epoxy resin is used in addition to aggregates such as crushed stone is doing. However, epoxy resins are slow to cure, especially at low temperatures (5 ° C. or lower), and are weak against ultraviolet rays, so that it is necessary to add an additional ultraviolet ray preventing agent and the workability is not excellent.

  In the water-permeable composition described in Patent Document 2, the coarse particles are distributed in a particle size range of 25 mm to 5 mm and a wide range. Therefore, there is a problem that the particle size tends to be non-uniform during construction, and variations in strength and water permeability are likely to occur.

  The water permeable roadbed material described in Patent Document 3, although the slowly cooled blast furnace slag and steel slag is used as a coarse product size range is wide. For this reason, there is a problem that the particle size tends to be non-uniform during construction, and variations in strength and water permeability are likely to occur.

  The hydraulic paving material described in Patent Document 4 is a mixture of blast furnace granulated slag, blast furnace slow-cooled slag, and converter slag, but has many fine-grained parts and is not a single particle size, so it has water permeability. Can not be used on pavements that require water permeability.

  The mixture described in Patent Document 5 is formed by mixing additives such as sodium chloride and magnesium chloride in addition to granulated blast furnace slag, and needs to be cured for about half a month for strength development. . Therefore, the construction time is long.

  Artificial turf made pavement structure described in Patent Document 6 has a rubber tip on the crushed stone layer a two-layer structure of the elastic layer which is bound with resin. Although this technique has improved the construction period and cost as compared with the conventional method, it is still not sufficient. Although in the case of securing the water permeability is stated to be kept high porosity of the elastic layer, thereby satisfying strength and permeability at the same time it is difficult to obtain.

  An object of the present invention is to overcome the above-described problems of the prior art and to provide a water permeable structure material having both high productivity and high quality stability while achieving both high strength and high water permeability.

The present invention provided to solve the above problems is as follows.
(1) A permeable structural material for constructing a water-permeable roadbed, comprising a blast furnace granulated slag and an aggregate not containing blast furnace granulated slag having a particle size of 5 mm or less, and the aggregate content is 40 The water-permeable structure material, wherein the water-permeable structure material has a uniformity coefficient of 6.73 or less.

  (2) The above-mentioned aggregate (1), wherein the aggregate is composed of one or more selected from the group consisting of steel slag, waste brick, waste concrete, crushed stone, gravel, crushed stone and sand. ) Is a water-permeable structure material.

  Here, as specific examples of “steel slag”, blast furnace slow-cooled slag and steelmaking slag are exemplified, and as specific examples of “crushed stone”, single-grain crushed stone, incised crushed stone, particle-size adjusted crushed stone are exemplified, Specific examples of “gravel” include mountain gravel, river gravel, and sea gravel.

  (3) The water-permeable structure material described in (1) or (2) above, which is used as an artificial turf roadbed material.

  Permeability structural material according to the present invention, sufficient strength and water-granulated blast furnace slag combines a water permeability obtained from it is a single particle size. In addition, since the granulated blast furnace slag and aggregate have a single particle size and the respective particle size ranges are narrow, the uniformity of the particle size distribution is high, and the quality variation as the water-permeable structure material is small.

  Since it has such excellent characteristics, the water-permeable structure material according to the present invention is easy to construct and is excellent in flatness of the construction surface. Moreover, by selecting the steel slag from the aggregate, in terms of by-product utilization is effective recycling of resources, leading to carbon reduction.

It is a graph which shows the relationship between the mixture ratio of an aggregate, and correction CBR. It is a graph which shows the relationship between the compounding rate of an aggregate, and a hydraulic conductivity. It is a graph which shows the particle size distribution of the slag used in the Example.

The water-permeable structure material of the present invention will be described below.
The water-permeable structural material according to the present invention is for constructing a water-permeable roadbed, and is composed of blast furnace granulated slag and aggregate not containing blast furnace granulated slag having a particle size of 5 mm or less, and the content of aggregate. Is 40% by mass or more, and the uniformity coefficient of the water-permeable structure material is 6.73 or less.

  Here, the "water-granulated blast furnace slag", a sandy slag vitreous was quenched by injecting a large amount of pressurized water to the molten slag produced from the blast furnace. Further, since the slag is rapidly heat-shrinked by being rapidly cooled, the slag is crushed autonomously during the manufacturing process. For this reason, the size of the granulated blast furnace slag is approximately 5 mm or less regardless of the production conditions (pressure, amount, etc. of the jet water). Therefore, even if the granulated blast furnace slag according to the present invention actually has a particle size of more than 5 mm, the particle size of such a blast furnace slag is 10 mm or less and the abundance ratio is at most several mass%. There are only exceptional cases where the contact with the pressure water was insufficient during the production process. Moreover, since the blast furnace granulated slag is autonomously crushed by heat shrinkage, as shown in Table 1, the blast furnace granulated slag has a lower uniformity coefficient than the blast furnace slow-cooled slag produced by mechanical crushing. (See, for example, “Branched Slag for Civil Engineering”, Steel Slag Association (1996), page 2).

  The "uniformity coefficient" (particle diameter corresponding to the particle size / 10%, which corresponds to 60%) in the mass passage percentage, particle diameter corresponding to 60% divided by the particle diameter corresponding to 10%, i.e. The smaller the uniformity coefficient, the smaller the variation in particle size.

  “No blast furnace granulated slag” in “Aggregates that do not contain granulated blast furnace slag” means that if the aggregate contains a large amount of granulated blast furnace slag, the content of granulated blast furnace slag is specified separately. It means that there is no such a large amount of granulated blast furnace slag, and even if the aggregate contains a small amount of granulated blast furnace slag, the amount of blast furnace granulated slag to be included separately If it is sufficiently small compared with the amount of the above, it is allowed to be included in the aggregate.

  Materials used as the aggregate are not particularly limited, but steel slag such as blast furnace slow-cooled slag, steelmaking slag (herein, “steelmaking slag” is a generic term for converter slag and electric furnace slag); waste Brick, waste concrete, crushed stone such as single-grain crushed stone, notched crushed stone, particle-size crushed stone, etc .; gravel such as mountain gravel, river gravel, sea gravel; If it exists, it is suitable without inhibiting the hydraulic characteristics of blast furnace granulated slag. Among these, use of steel slag is particularly preferable from the viewpoint of recycling because it is used as a by-product.

Subsequently, the contents of granulated blast furnace slag and aggregate will be described.
In order to determine these content ranges, the water permeability and modified CBR of the structural material obtained by mixing blast furnace granulated slag and aggregate (particle size of 5 mm or less) were confirmed. At that time, blast furnace slow cooling slag, which is superior in terms of resource recycling, was selected as an aggregate among the objects to be mixed. Other aggregates (5 mm or less) have the same strength and water permeability. As shown in Table 2 below, the aggregate mixing ratio was changed, and the modified CBR and water permeability of the structural material were investigated. Table 2 shows the 60% equivalent particle size, the 10% equivalent particle size, and the uniformity coefficient obtained from these at each blending ratio.

The results are as shown in FIGS.
FIG. 1 is a graph showing the relationship between the composition ratio of aggregate and the modified CBR of the structural material. The “corrected CBR value” is an index indicating the quality standard of the roadbed material and the embankment material, and generally corresponds to a degree of compaction of 95% of the maximum dry density obtained by the name E-b of JIS A1210. Refers to the CBR value.

As shown in FIG. 1, it is confirmed that the test result of the modified CBR of the structural material is equal to or higher than the target value of 80% (roadbed material JIS standard value) when the aggregate content is 40% by mass or higher. did.
FIG. 2 is a graph showing the relationship between the composition ratio of the aggregate and the water permeability of the structural material. The “water permeability coefficient” means a proportional coefficient based on the relationship that the permeation speed of the water flowing through the gap in the porous body is proportional to the road gradient. The target value of the hydraulic conductivity was 20 mm / H, which is defined as heavy rain by the Japan Meteorological Agency, that is, 5.6 × 10 ⁻⁴ cm / s.

  As shown in FIG. 2, as the mixing ratio of the aggregate is 30 to 60 wt%, that is, in the case of 3.92 to 6.73 as uniformity coefficient of the structural material, the mixing ratio of the aggregate increases, the structure Although the water permeability coefficient of the material showed a decreasing tendency, it was more than the target value, indicating the desired water permeability. In contrast, 70% by weight blending ratio of the aggregate, that is, in the case of 8.06 as uniformity coefficient of structural material has poor water permeability, normal test results were not obtained.

  While the above results the mixture ratio of the aggregate 40% by mass or more from that in the uniformity coefficient of the structural material 6.73 or less (hereinafter 60% by weight blending ratio of the aggregate equivalent to the result of the above) Thus, it was confirmed that both target values of strength (corrected CBR) and water permeability (water permeability coefficient) were satisfied. Furthermore, since the particle size of the blast furnace slow-cooled slag that is the aggregate of this time is 5 mm or less, the particle size of the structural material that is a mixture with the blast furnace granulated slag is also approximately 5 mm or less. Therefore, hardly occurs variation in particle size, has excellent surface flatness, there is an advantage that leads to shortening of the construction period of the rolling pressure or the like.

  From the above investigation, sufficient water permeability is realized by using blast furnace granulated slag at a content of 60 to 40% by mass, and sufficient by using blast furnace slow-cooled slag at a content of 40 to 60% by mass. It was confirmed that strength was obtained. Also, if equally sized particle size distribution, not limited to the slowly cooled blast furnace slag, steel slag, and further, can also be used for other inorganic materials. However, from the viewpoint of resource recycling, it is better to use blast furnace slow cooling slag or steelmaking slag. Furthermore, by limiting to 5 mm or less, variation in particle size distribution is reduced. In addition, the variation in quality is reduced, the surface flatness is increased, and the construction can be performed easily, leading to a shortened construction period.

  The water-permeable structure material of the present invention is preferably used as an artificial turf roadbed material. Artificial turf roadbed materials have a lower required surface strength than ordinary roadbed materials. Therefore, the use of water-permeable structural material of the present invention as artificial turf roadbed material, the strength of the structural material itself is high, there is no need to lay an asphalt mixture or the like under the roadbed material. For this reason, the two-layer construction (ascon + roadbed material) performed in the conventional artificial turf roadbed material can be simplified to one-layer construction, and the construction cost and the construction period can be shortened.

EXAMPLES Hereinafter, although an Example is shown and this invention is demonstrated concretely, this invention is not restrict | limited to the following Example.
The work was carried out with water-permeable structural materials produced under the blending conditions shown in Table 3. In the construction, permeable blast furnace slag and aggregated blast furnace slow-cooled slag are laid on the current roadbed, compacted with rollers, and then rolled onto artificial turf on the top surface. Laid.

  Further, as shown in FIG. 3, the particle size of the slag used at this time is a particle size distribution of 5 mm or less for both the blast furnace granulated slag and the aggregate blast furnace slow-cooled slag, and the blast furnace granulated slag has a particle size distribution. It was a single particle size with a small width. Note that “particle size” in FIG. 3 has the same meaning as particle size.

  The strength and water permeability of the water permeable structural material thus obtained are the results shown in Table 4, and the respective target values could be achieved.

  Moreover, the finish of flatness at the time of construction was satisfactory, and two years have passed since the current construction, but there was no problem with flatness and water permeability.

Claims (3)

  A permeable structural material for constructing a water-permeable roadbed, comprising blast furnace granulated slag and aggregate not containing blast furnace granulated slag having a particle size of 5 mm or less, and the aggregate content is 40 mass% or more The uniformity coefficient of the said water-permeable structure material is 6.73 or less, The water-permeable structure material characterized by the above-mentioned.   The aggregate is composed of one or more selected from the group consisting of steel slag, waste brick, waste concrete, crushed stone, gravel, crush and sand. Water permeable structural material.   The water-permeable structure material according to claim 1 or 2, wherein the water-permeable structure material is used as an artificial turf roadbed material.

Images