JP2005133064A - Admixture for soil pavement and soil pavement using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an admixture, which is incorporated in a soil pavement and adds resistance to mud and cracking resistance to the soil pavement while maintaining sufficient strength. <P>SOLUTION: The admixture for a soil pavement contains 100 pts.wt. of a polyvinyl alcohol polymer with the saponification degree of 80-99% and the polymerization degree of 50-4,000 and 30-240 pts.wt. of one or a plurality of plasters selected from the type II of anhydrous plasters, the type III of anhydrous plasters, dihydrate gypsum and hemihydrate gypsum. The admixture also contains 10-300 pts.wt. of a hydraulic material to 100 pts.wt. of the polyvinyl alcohol polymer, and further contains 1-20 pts.wt. of amorphous silica to 100 pts.wt. of the admixture for the soil pavement. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a soil pavement admixture and a soil pavement using the same.

  Summer road pavements, especially asphalt pavements, are black in color and easily absorb infrared rays. For this reason, the road surface temperature becomes very high, and problems such as a heat island phenomenon that the temperature does not decrease even at night occur in urban areas. The concrete pavement also has the same problem as the asphalt, although the road surface temperature rises. Therefore, a soil pavement that is mainly composed of clay minerals that can hold rainwater and that can relax the ambient temperature by using the heat of vaporization of water is being reviewed.

The soil pavement has problems such as being wet by a large amount of rainwater and cracking by drying. Various methods for solving these problems have been studied. A construction method in which polyvinyl alcohol is mixed with a soil material (see, for example, Patent Document 1 and Patent Document 2), and a construction method in which magnesium oxide and polyvinyl alcohol are mixed (for example, a patent) A method of mixing vinyl acetate resin and Portland cement or calcium sulfate (see, for example, Patent Document 4) is known.
JP-A-62-1907 (Claims) JP 2000-7926 (Claims, paragraph number 0022) JP 2003-64618 A (Claims) JP-A-8-134450 (Claims)

  The method of mixing polyvinyl alcohol with the soil material and the method of mixing magnesium oxide and polyvinyl alcohol are insufficient in strength as a soil pavement, and it is difficult to uniformly mix the soil material and polyvinyl alcohol, and there is a problem in workability was there. The method of mixing vinyl acetate resin and Portland cement or calcium sulfate has a problem that cracking resistance is insufficient and the usable soil material is limited to hard clay.

  The present invention provides a soil pavement admixture capable of imparting anti-sludge and crack resistance to a soil pavement while maintaining the strength as a soil pavement, and a soil pavement using the same. It is.

  The present invention comprises 100 parts by weight of polyvinyl alcohol having a saponification degree of 80 to 99% and a polymerization degree of 50 to 4000, and one or more kinds selected from the group of type II anhydrous gypsum, type III anhydrous gypsum, dihydrate gypsum, and hemihydrate gypsum. The present invention relates to a soil pavement admixture characterized by containing 30 to 240 parts by weight of gypsum, and the soil pavement admixture is added to a soil material, mixed, and rolled to finish on the road surface. Related to dirt pavement.

  By using the admixture for earth paving of the present invention, an earth paving body having improved mudproofing and cracking resistance while maintaining strength can be obtained.

  The present invention is an admixture for soil pavement using polyvinyl alcohol and gypsum in combination, and when added to a soil material, the viscosity and shearing force are adjusted so that the strength, mudproof property, and crack resistance are improved. It is characterized by giving to.

  The polyvinyl alcohol preferably has a saponification degree of 80 to 99%. If the degree of saponification is less than 80%, the admixture for soil paving may become too viscous and difficult to mix uniformly with the soil material. If it exceeds 99%, the admixture for soil paving itself is prepared. It becomes difficult to do. The polymerization degree of polyvinyl alcohol is preferably about 50 to 4000. If it is less than 50, the viscosity of the admixture for soil pavement is not sufficient, and if it exceeds 4000, the viscosity becomes too high and it may be difficult to mix with the soil material.

As the gypsum, type II anhydrous gypsum, type III anhydrous gypsum, dihydrate gypsum, and hemihydrate gypsum can be used. Among these, type II anhydrous gypsum is preferable because the strength development of the soil pavement is excellent. The fineness of gypsum is preferably about 1000 to 6000 cm ² / g in terms of Blaine specific surface area. Is less than 1000 cm 2 / ^g may result in insufficient strength of the soil pavement, there is a possibility that 6000 cm 2 / ^g will the gypsum molecules beyond can not be obtained with uniform soil pavement by aggregation.

  The blending amount of gypsum is preferably 30 to 240 parts by weight and more preferably 65 to 150 parts by weight with respect to 100 parts by weight of polyvinyl alcohol. If the blending amount of gypsum is less than 30 parts by weight, there is a possibility that the strength and mudproof property of the soil pavement may not be obtained.

  The gypsum used in the present invention is not particularly limited as long as it is a substance containing these gypsum components, and is a free lime-auin-II type anhydrous gypsum expansion material known as a concrete expansion material (for example, Japanese Patent Publication No. 42-021840 and Japanese Patent Application Laid-Open No. 07-232944), free lime-calcium silicate type II anhydrous gypsum expansion material (for example, see Japanese Patent Publication No. 53-031170), etc. it can. When employing a concrete expansion material, the gypsum component in the concrete expansion material is preferably blended so as to be 30 to 240 parts by weight with respect to 100 parts by weight of polyvinyl alcohol, and is 65 to 150 parts by weight. It is more preferable to blend as described above.

  The hydraulic substance is a substance that condenses and hardens due to a chemical reaction with water, and is blended in order to further improve the mudproof property of the soil pavement. The hydraulic substance is not particularly limited, and examples thereof include various Portland cements such as ordinary Portland cement, early-strength Portland cement, ultra-high-strength Portland cement, low heat Portland cement, and moderately hot Portland cement, and these Portland cements. In addition, various mixed cements in which blast furnace slag, fly ash and silica are mixed, filler cement in which limestone powder and the like are mixed, eco cement, and the like can be used.

  The blending amount of the hydraulic substance is preferably 10 to 300 parts by weight, and more preferably 30 to 100 parts by weight with respect to 100 parts by weight of polyvinyl alcohol contained in the admixture for pavement. If the amount of the hydraulic substance is less than 10 parts by weight, the effect of further improving the mud-proof property may not be obtained, and if it exceeds 300 parts by weight, the crack resistance may be lowered.

  Amorphous silica is blended in order to further improve the anti-sludge property and crack resistance of the soil pavement. Although it does not specifically limit as an amorphous silica, A silica fume, metakaolin, etc. can be utilized.

  The blending amount of the amorphous silica is preferably 1 to 20 parts by weight and more preferably 3 to 10 parts by weight with respect to 100 parts by weight of the admixture for soil paving. If the blending amount of the amorphous silica is less than 1 part by weight, the effect of further improving the anti-sludge property and cracking resistance may not be obtained. There is a risk that the strength will decrease.

  Polyvinyl alcohol can also improve the water resistance of the soil pavement and further increase the crack resistance by containing modified polyvinyl alcohol in the polyvinyl alcohol. The modified polyvinyl alcohol can be obtained by a conventionally known method. For example, it can be obtained by reacting a cyclic acid anhydride with polyvinyl alcohol in an anhydrous state and then esterifying a hydroxyl group in the molecular structure. 20% or less is preferable and, as for the ratio contained in polyvinyl alcohol of this modified polyvinyl alcohol, 5 to 15% is more preferable. If the content of the modified polyvinyl alcohol exceeds 20%, the water retention of the soil pavement becomes too high, and the soil pavement may be easily mud.

The amount of the admixture for soil paving is not specified because it is affected by the state of the soil material, but it is usually preferable to add about 0.5 to 20 kg with respect to 1 m ^{3 of} the soil material. If the blending amount of the soil pavement admixture is less than 0.5 kg, the intended effect may not be obtained, and if it exceeds 20 kg, molding may become difficult and pavement workability may be deteriorated.

  Although the moisture content of the soil material to which the admixture for soil pavement is added is not particularly limited, it is preferable that the moisture content is 10 to 20% from the viewpoint of obtaining predetermined strength, mudproof property, and crack resistance. . When the moisture content of the target soil material is outside this range, the moisture content may be adjusted by water addition or drying.

  The soil material may be any material that is generally used as a soil pavement, and may be appropriately selected according to the purpose, such as sand, hard clay, and clay.

  The admixture for soil pavement may be used by adding the admixture for soil pavement to the soil material, stirring and mixing to obtain mixed soil, spreading the mixed soil, and then rolling and compacting.

  In the soil pavement admixture of the present invention, the performance of the soil pavement is further enhanced by blending additives that have been conventionally used as an improvement material for soil pavements within a range that does not impede its effect. You can also. Examples of additives include slaked lime, quicklime, magnesium oxide, sodium chloride, other water-soluble polymers, water-absorbing polymers, agglomerates such as aluminum sulfate, polyaluminum chloride, iron sulfate, and polyiron chloride, organic materials, There are inorganic fiber materials.

"Example 1"
As shown in Table 1, the admixture for soil pavement in Example 1 of the present invention was 100 parts by weight of polyvinyl alcohol (B-24) having a saponification degree of 88% and a polymerization degree of 2400, A blend of 45 parts by weight of type II anhydrous gypsum having a specific surface area of 5000 cm ² / g of Blaine. In this example, 10 kg of this admixture for soil pavement was added per 1 m ^{3 of} Hiroshima sand sand (hard, moisture content 11.5%), which is a soil material, and sufficiently mixed and stirred with a mixer. Thereafter, the sample was packed into a mold and compacted, and evaluated by various tests shown below. The results are shown in Table 1. Other examples and comparative examples shown below are the same as those in this example unless otherwise specified.
"Measuring method"
Strength: Evaluated according to the uniaxial compression test method (pavement test method handbook) of road-recycled cement and asphalt emulsion stabilization treatment roadbed materials, and those that were cured for 7 days and had a value of 1 MPa or more A value of 0.5 to 1 MPa was indicated by Δ, and a value less than that was indicated by ×.
Mud-proofing property: A specimen cured for 7 days was immersed in water for 24 hours and evaluated by its dispersibility in water. A case where dispersion was suppressed with respect to the soil material itself was indicated as ◎, a case where the dispersion was slightly suppressed was indicated as ○, a case of the same degree was indicated as 、, and a case of poor was indicated as ×.
Crack resistance: A specimen was prepared by packing a sample into a wooden form of 1000 × 1000 × 100 mm, and the occurrence of cracks was observed in a room adjusted to a temperature of 20 ° C. and a humidity of 60% RH. For the soil material itself, ◎ indicates that the crack resistance is excellent, ◯ indicates that it is slightly superior, △ indicates that it is approximately the same, and × indicates that it is poor.

"Examples 2 to 26"
Using the polyvinyl alcohol, gypsum, hydraulic substance, and amorphous silica shown in Table 1, Table 2 and Table 3, a pavement admixture was prepared in the same manner as in Example 1, and the strength, mud-proof property, and crack resistance were made. The properties were measured in the same manner as in Example 1. The results are shown in Table 1, Table 2 and Table 3. The modified polyvinyl alcohol used in Examples 16 to 19 was obtained by adding 50 g of polyvinyl alcohol of Example 1 and 20 g of maleic anhydride to 200 ml of dioxane as a solvent and reacting at 80 ° C. for 3 hours. It is.

Here, in Tables 1 to 3, the types of gypsum are: A: type II anhydrous gypsum (Brain specific surface area 5000 cm ² / g), B: type III anhydrous gypsum (Brain specific surface area 5000 cm ² / g), C: two Water gypsum (Blaine specific surface area 5000 cm ² / g), D: hemihydrate gypsum (Blaine specific surface area 5000 cm ² / g), E: free lime-auin-II type anhydrous gypsum expansion material (manufactured by Denki Kagaku Kogyo Co., Ltd.), F : Free lime-calcium silicate-type II anhydrous gypsum expansive material (manufactured by Taiheiyo Material Co., Ltd.), the types of hydraulic materials are: a: normal Portland cement (manufactured by Denki Kagaku Kogyo Co., Ltd.), b: early strength Portland cement (electric Chemical Industry Co., Ltd.), c: Alumina cement (Electrochemical Industry Co., Ltd.). The types of amorphous silica are I: silica fume (BET specific surface area 23 m ² / g), II: metakaolin (brane specific surface area 5000 cm ² / g), and the types of soil materials are: Hard, moisture content 11.5%), B: Kanto loam soil (soft, moisture content 9.3%) from Chiba Prefecture.

"Comparative Examples 1-2"
A pavement admixture was prepared in the same manner as in Example 1 using the polyvinyl alcohol and gypsum shown in the blending column of Table 2, and the strength, mud-proof property, and crack resistance were measured in the same manner as in Example 1. It is. The results are shown in Table 3.

Although not shown in Table 1, Table 2 and Table 3, the soil material not containing the admixture for soil pavement of the present invention has low strength, mud resistance and crack resistance regardless of its type. When blended in excess of 20 kg per 1 m ³ , the mud-proof property and crack resistance were lowered.

Claims (5)

100 parts by weight of polyvinyl alcohol having a saponification degree of 80 to 99% and a polymerization degree of 50 to 4000, and one or more kinds of gypsum selected from the group of type II anhydrous gypsum, type III anhydrous gypsum, dihydrate gypsum, and hemihydrate gypsum 30 to 240 An admixture for soil pavement characterized by containing parts by weight. The admixture for soil pavement according to claim 1, further comprising 10 to 300 parts by weight of a hydraulic substance with respect to 100 parts by weight of polyvinyl alcohol. An admixture for soil pavement, wherein 1 to 20 parts by weight of amorphous silica is further blended with 100 parts by weight of the admixture for soil pavement according to claim 1 or 2. The pavement admixture according to any one of claims 1 to 3, wherein the polyvinyl alcohol contains a modified polyvinyl alcohol in a proportion of 20% or less. A soil pavement obtained by adding and mixing the soil pavement admixture according to any one of claims 1 to 4 to a soil material, spreading the mixture on a road surface, and then rolling and finishing.