JP6535636B2 - Repair method of roadbed - Google Patents

Description

  The present invention relates to a method of repairing a roadbed, and more particularly, to a method of repairing a roadbed using a roadbed material containing an expandable mineral.

  In addition to natural crushed stone, steel slag, recycled material and the like are used as roadbed materials to be laid for roadbed formation such as roads and parking lots. When these roadbed materials contain expansive minerals such as free CaO and free MgO, they react with water to form CaO hydrate, MgO hydrate, etc., and such hydrates become the original minerals. Since the volume per unit mass is large compared with that, volume expansion may cause uplift, deformation, destruction and the like of the roadbed. In addition, the roadbed material referred to here includes earthwork materials used for temporary roads and ground preparation materials.

  Conventionally, as a method of repairing the above-mentioned uplift, deformation, breakage, etc. of the roadbed and preventing it, a method of forming a joint on the roadbed to absorb expansion, or removing a part of the roadbed into a groove shape Methods have been proposed for absorbing expansion by filling the void portion of the groove and the groove portion with foamed cement milk or non-caking granular material (see, for example, Patent Documents 1 to 3). However, in these conventional methods, there is a limit to the amount of expansion that can be absorbed, and there is a problem that depending on the amount of expansion, there is a possibility of causing uplift, deformation, breakage, etc. of the roadbed.

JP, 2010-163759, A JP, 2010-71066, A JP, 2010-71067, A

  The problem to be solved by the present invention is to reliably repair uplift, deformation, breakage and the like of the roadbed using the roadbed material containing the expandable mineral, and at the same time reliably prevent the occurrence of such bumps, deformation, and destruction. It is in place to provide a roadbed repair method that can be done.

  The present invention for solving the above-mentioned problems is a method of repairing a roadbed using a roadbed material containing an expandable mineral, wherein the roadbed material is exposed from the surface layer or the base layer of the pavement and water insoluble in the exposed roadbed material. The present invention relates to a method of repairing a roadbed characterized in that a superabsorbent resin is added and mixed, and then the required amount of the mixture is laid again as a roadbed material.

  The roadbed repair method according to the present invention (hereinafter referred to as the repair method of the present invention) is a roadbed repair method using a roadbed material such as steel slag containing expandable minerals such as free CaO and free MgO. In the repair method of the present invention, first, the roadbed material is exposed from the surface layer or base layer of the pavement. Next, a water-insoluble highly water-absorbent resin is added to the exposed road base material and mixed. Finally, the required amount of the mixture is laid again as roadbed material.

  Specifically, in the case of a road or parking lot paved with asphalt, for example, after removing the asphalt layer first, the roadbed is excavated, and the roadbed material is crushed and laid down. Next, the water-insoluble highly water-absorbing resin is dispersed as uniformly as possible on the spread base material and mixed as uniformly as possible by a stabilizer or the like. Finally, the required amount of the mixture is spread again, compacted and re-paved with asphalt.

  The water-insoluble highly water-absorbent resin used in the repair method of the present invention is generally used for sanitary materials such as disposable diapers and sanitary products, and is also used for non-hygienic materials such as soil water retention agents and cold storage agents. A resin which is almost insoluble in water and swells by absorbing water by high water absorption, which is defined in JIS K 7223 (1996) and JIS K 7224 (1996).

  Examples of the water-insoluble highly water-absorbent resin that can be used in the repair method of the present invention include polyacrylic acid (salt), polysulfonic acid (salt), maleic anhydride (salt), polyacrylamide, polyvinyl alcohol, and poly Ethylene oxide type, polyaspartic acid (salt) type, polyglutamic acid (salt) type, polyalginic acid (salt) type, starch type, cellulose type, etc. may be mentioned, among which polyacrylic acid type and / or poly type The acrylate type is preferred. The term "system" as used herein refers to having them as the main component, and may be composed of not only a single structural unit but also two or more types of structural units, and the polymerization used in the synthesis An initiator, an internal crosslinking agent, a chain transfer agent, a chelating agent, a crosslinking inhibitor, a surfactant, etc. may be contained, and the synthesis method thereof is such as aqueous solution polymerization, reverse phase emulsion polymerization, reverse phase suspension polymerization, etc. Either method may be used.

  As a commercial item of the water-insoluble super absorbent polymer as described above, Sanrio Chemical Co., Ltd. trade name Sun Fresh GT or Aqua Pearl DS, a crosslinker of acrylic acid polymer (salt), Nippon Catalyzer trade name Aqua Lick CA, acrylic acid polymer partial sodium salt cross-linked product, trade name Aquakeep SA, manufactured by Sumitomo Seika Chemicals Co., Ltd., and cellulose resin, trade name Sunrose SLD, manufactured by Nippon Paper Industries Co., Ltd. In any case, as the water-insoluble highly water-absorbent resin used in the repairing method of the present invention, one having a particle diameter of 2000 μm or less is preferable.

  When the water-insoluble highly water-absorbent resin is added to the road-base material and mixed, the highly water-absorbent resin absorbs the pore water of the road-base material to increase its volume. On the other hand, the expansive mineral in the roadbed material takes water from the highly water-absorbent resin over a long period of time to be hydrated and expanded, and the highly water-absorbent resin contracts by releasing the water. In the repair method of the present invention, the shrinkage allowance of the superabsorbent polymer is used to absorb the hydration and expansion of the expandable mineral. Even though the amount of superabsorbent resin added is small, the amount of water absorption and volume increase are large, so it can be applied to repair of a roadbed having a large residual volume expansion ratio exceeding several percent. By mixing a water-insoluble highly water-absorbing resin into the base material, the expansion of the expandable mineral in the base material can be absorbed in situ, and the amount of expansion absorption is larger than in the case of providing joints and grooves .

  In the repair method of the present invention, the water-insoluble highly water-absorbent resin is added to the base material and mixed, but it is also possible to add a composition containing the water-insoluble super absorbent resin to the base material and mixed. As such a composition, a mixture of a water-insoluble highly water-absorbent resin and inorganic powder such as silica sand, calcium carbonate, granulated slag, glass cullet, etc., a water-insoluble highly absorbent resin and water or a hydrophilic solvent, For example, a mixture with ethyl alcohol is mentioned.

  The repair method of the present invention does not limit the use ratio of the water-insoluble superabsorbent resin or the composition containing the same to the roadbed material, but it contains the water-insoluble resin or this to the roadbed material. The composition is preferably added so as to be 0.01 to 0.5% by mass as a water-insoluble highly water-absorbent resin, and more preferably 0.05 to 0.3% by mass. The place to be added may be a site where the roadbed material is exposed from the surface layer or the base layer of the pavement, or may be a transfer destination of the exposed roadbed material, for example, a factory, but it is preferable to add and mix at the site.

  FIG. 1 exemplifies the relationship between the addition amount (use ratio, mass%, horizontal axis) of the water-insoluble super absorbent polymer to the road base material and the expansion absorption amount (volume%, vertical axis) by the added super absorbent resin FIG. 1 is a graph, dotted line 1 in the case of superabsorbent resin with a water absorption of 10 g / g, solid line 2 in the case of a superabsorbent resin with a water absorption of 16 g / g, dashed dotted line 3 with a water absorption of 20 g In the case of a highly water-absorbent resin of 1 g / g, a two-dot chain line 4 indicates the case of a highly water-absorbent resin having a water absorption of 30 g / g. For example, when a superabsorbent polymer having a water absorption amount of 16 g / g is used, the addition amount is 0.1% by mass, which indicates that the expansion absorption amount obtained by the following equation 1 is about 3.2% by volume (The bulk density of the road base material is 2.0, and the bulk density of the highly water-absorbent resin at the time of water absorption is 1.0.) The relationship between the added amount and the expansion absorption amount, which varies depending on the water absorption amount of the superabsorbent polymer, is that when the expansion ratio of the base material is less than the expansion absorption amount, the base material does not expand, so the relation with expansion of the base material Then, it is a weight in deciding what kind of added amount of superabsorbent resin of what kind of water absorption amount is used.

  According to the present invention, it is possible to reliably repair uplift, deformation, breakage and the like of the roadbed using the roadbed material containing the expansive mineral, and at the same time reliably prevent the occurrence of such bumps, deformation, and destruction. effective.

The graph which illustrates the relationship between the addition amount (use ratio, mass%, horizontal axis) of the water-insoluble highly water-absorbing resin with respect to the base material and the expansion absorption amount (volume%, vertical axis) by the added super absorbent resin.

  After removing the asphalt layer from the raised part of the asphalt pavement surface, the roadbed was excavated, and the roadbed material using steel slag and the like containing expandable minerals was crushed and spread. A total of 6 construction sections were established with a length of 20 m, a width of 4 m, a thickness of 0.2 m, and a roadbed material volume of 32 t, and construction was carried out as follows.

Comparative Example 1
The roadbed material laid out as described above was compacted as it was and was paved with asphalt.

Comparative Example 2
In the roadbed material laid out as described above, grooves of 30 cm in width were provided at intervals of 3 m in the longitudinal direction, and asphalt was paved.

Examples 1-4
A highly water-absorbent resin is dispersed on the roadbed material laid out as described above so that the addition amount etc. shown in Table 1 is obtained and mixed so that both sides become uniform with a stabilizer. It was pressed and paved with asphalt.

In each test section, hit a total of 15 observation ridges on the asphalt pavement surface at a predetermined interval, measure the displacement of height of these observation ridges after one year, three years and five years, and average the values The results are summarized in Table 1 as the expansion ratio (%) divided by the thickness of the base course material.

In Table 1,
A1: Acrylic acid-based water absorbent resin (trade name AQUAKeep CA60N TYPE II, manufactured by Sumitomo Seika Co., Ltd., catalog value: median particle diameter 300 μm)
A2: Cellulose-based water-absorbent resin (trade name Sunrose SLD-F1, manufactured by Nippon Paper Industries Co., Ltd., catalog value, average particle diameter 50 to 60 μm)

  As apparent from the results of Table 1, according to the present invention, expansion of the base material containing the expandable mineral can be substantially prevented, and the base can be reliably repaired.

Claims (7)

  A method of repairing a roadbed using a roadbed material containing an expandable mineral, which comprises exposing the roadbed material from the surface layer or the base layer of the pavement and adding a water-insoluble highly water-absorbent resin to the exposed roadbed material and mixing , A method of repairing a roadbed, comprising laying the required amount of the mixture as a roadbed material again.   A method of repairing a roadbed using a roadbed material containing an expandable mineral, comprising exposing the roadbed material from the surface layer or the base layer of the pavement and adding a composition containing a water-insoluble highly water-absorbent resin to the exposed roadbed material. In addition, after mixing, the required quantity of the mixture is again laid as a subgrade material, The repair method of the subgrade characterized by the above-mentioned.   3. The method of repairing a roadbed according to claim 2, wherein the composition is a mixture of a water-insoluble super absorbent polymer and an inorganic powder.   3. The method of repairing a roadbed according to claim 2, wherein the composition is a mixture of a water-insoluble superabsorbent polymer and water or a hydrophilic medium.   The method for repairing a roadbed according to any one of claims 1 to 4, wherein the water-insoluble super absorbent polymer is of polyacrylic acid type and / or polyacrylate type.   The method for repairing a roadbed according to any one of claims 1 to 5, wherein the water-insoluble highly water-absorbent resin has a particle diameter of 2000 μm or less.   The water-insoluble highly water-absorbent resin or a composition containing the same is added to the road base material to be 0.01 to 0.5% by mass as a water-insoluble highly water-absorbent resin. The repair method of the roadbed of one paragraph statement.

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