Method for forming pavement containing natural stone

Abstract

To provide a formation method for natural stone-containing pavement having excellent compressive strength, bending strength, torsion resistance, and durability, and being able to relatively easily form a natural stone-containing pavement having an excellent design property with natural stone.SOLUTION: A formation method for natural stone-containing pavement includes steps of: mixing shrinkage-compensating mortar, aggregate, and water to obtain a natural stone-containing pavement material mixture; forming a pre-hardening mixture layer by pouring the natural stone-containing pavement material mixture onto a roadbed or roadway; and scattering natural stones on the surface of the pre-hardening mixture layer.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a method for forming a natural stone-containing pavement that can relatively easily form a natural stone-containing pavement that has excellent compressive strength, bending strength, torsional resistance, and durability, and has excellent design properties due to the natural stones. [Background technology]

[0002] For example, sidewalks, park walkways, parking lots, etc. are often paved with not only ordinary concrete or ordinary asphalt, but also with decorative landscape paving such as natural stone paving.

[0003] For example, Patent Document 1 discloses a technology relating to landscape pavement, in which 10 to 15% by weight of a phosphorescent pigment is mixed into a liquid binder resin, and this binder resin is mixed with aggregate in which granular main aggregate with an average particle size in the range of 1 to 4 mm accounts for 50% by volume or more, and the mixture is laid on the pavement surface. Patent Document 1 is a technology that aims to make the pavement surface sufficiently glow by incorporating a phosphorescent pigment. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2006-83680 Summary of the Invention [Problem to be solved by the invention]

[0005] On the other hand, the landscape pavement formed by the technique of Patent Document 1 does not necessarily have sufficient compressive strength, bending strength, and durability, and improvements in these areas have been desired. [Means for solving the problem]

[0006] As a result of intensive research conducted by the inventors to solve the above problems, they discovered that when forming a pavement containing natural stones, a paving material mixture obtained by mixing non-shrink mortar, aggregate, and water is used, and this mixture is poured onto the roadbed or subgrade to form a pre-hardening mixture layer, and natural stones are scattered on the surface of the pre-hardening mixture layer thus formed, thereby making it possible to relatively easily form a pavement containing natural stones that has excellent compressive strength, flexural strength, and durability, and that has excellent design potential due to the natural stones, and thus they have completed the present invention.

[0007] That is, according to the present invention, there is provided a method for forming a pavement containing natural stones, which comprises the steps of: mixing non-shrink mortar, aggregate, and water to obtain a pavement mixture; pouring the pavement mixture onto a roadbed or subgrade to form a pre-hardening mixture layer; and scattering natural stones on the surface of the pre-hardening mixture layer.

[0008] In the method for forming a natural stone-containing pavement of the present invention, the non-shrink mortar is preferably prepared by mixing cement, fine aggregate, and an admixture containing low-substituted hydroxypropyl cellulose and an expansive material. In addition, it is preferable that the method for forming a pavement containing natural stones of the present invention further comprises a step of hardening the pre-hardening mixture layer while leaving at least a portion of the natural stones exposed from the surface of the pre-hardening mixture layer. [Effects of the Invention]

[0009] According to the present invention, it is possible to relatively easily form a pavement containing natural stones that is excellent in compressive strength, bending strength, torsional resistance and durability, and that has excellent design potential due to the natural stones. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a process diagram illustrating a method for forming a pavement containing natural stones according to one embodiment of the present invention. [Figure 2]FIG. 2 is a graph showing the measurement results of the compressive strength and bending strength of the natural stone-containing pavement according to Example 1. [Figure 3] 3(A) to 3(C) are photographs of the surface of the natural stone-containing pavement formed in the example. [Figure 4] FIG. 4 is a graph showing the results of measuring the torsional resistance of the natural stone-containing pavement according to Example 1 and the natural stone-containing pavement according to Comparative Example 1. DETAILED DESCRIPTION OF THE INVENTION

[0011] The method for forming a natural stone-containing pavement of the present invention comprises: mixing non-shrink mortar, aggregate, and water to obtain a paving material mixture; pouring the paving material mixture onto a roadbed or subgrade to form a pre-hardened mixture layer; and scattering natural stones on the surface of the pre-hardening mixture layer.

[0012] A method for forming a pavement containing natural stones according to one embodiment of the present invention will be described below with reference to Fig. 1. Note that the method for forming a pavement containing natural stones according to the present invention is not particularly limited to the method for forming a pavement containing natural stones according to one embodiment shown in Fig. 1, which will be described below.

[0013] First, in this embodiment, a required amount of water is charged into a ground mixer (FIG. 1(A)). Note that, although a method using a ground mixer is exemplified here as a mixing device, the method is not particularly limited to a ground mixer, and various mixing devices such as a hand mixer can be used without limitation.

[0014] Next, the required amount of non-shrinkage mortar is added to the ground mixer containing the water, and the water and non-shrinkage mortar are mixed (FIG. 1(B)).

[0015] In this embodiment, it is preferable to use a non-shrinkage mortar made by mixing an admixture containing low-substituted hydroxypropyl cellulose and an expansion agent with cement and fine aggregate, thereby making it possible to make the natural stone-containing pavement formed by the forming method of this embodiment superior in compressive strength, flexural strength and durability.

[0016] Low-substituted hydroxypropyl cellulose is hydroxypropyl cellulose having a degree of substitution of 1.0 or less, preferably 0.1 to 0.7, more preferably 0.2 to 0.4. Here, the degree of substitution refers to the average number of moles of propylene oxide added per pyranose ring of cellulose. Preferably, propylene oxide is added as a hydroxypropoxy group. Preferably, the low-substituted hydroxypropyl cellulose is one in which 300 to 1,000 pyranose rings are polymerized, and more preferably, one in which 500 to 6,000 pyranose rings are polymerized.

[0017] The amount of low-substituted hydroxypropyl cellulose used is preferably 0.01 to 0.5 parts by weight, more preferably 0.01 to 0.1 parts by weight, based on 100 parts by weight of cement.

[0018] The expansive material is not particularly limited as long as it is an inorganic material that expands by undergoing a hydration reaction to form crystals, and examples of the expansive material that can be used include calcium sulfa aluminate, gypsum, and lime. The content of the expansive material is preferably 3 to 8 parts by weight, more preferably 4 to 7 parts by weight, per 100 parts by weight of cement.

[0019] Furthermore, it is preferable that the admixture constituting the non-shrink mortar further contains a water-reducing agent and / or a foaming agent.

[0020] The water-reducing agent is not particularly limited as long as it has a water-reducing effect and can be used for mortar, and may be what is called a high-performance water-reducing agent or a high-performance air-entraining water-reducing agent. Examples include naphthalenesulfonic acid-based, melamine sulfonic acid-based, lignin sulfonic acid-based, and polycarboxylic acid-based water-reducing agents. Of these, naphthalenesulfonic acid-based or polycarboxylic acid-based high-performance water-reducing agents are preferably used. The content of the water-reducing agent may be appropriately selected depending on its components and type within a range that allows fluidity to be achieved at a predetermined water / cement weight ratio. For example, when a naphthalenesulfonic acid-based high-performance water-reducing agent is used, the content is preferably 0.5 to 1.5 parts by weight, more preferably 0.8 to 1.2 parts by weight, per 100 parts by weight of cement.

[0021] The foaming agent is preferably aluminum metal, aluminum alloy, or other aluminum metals, because they react easily with the alkali of cement to efficiently foam hydrogen bubbles. The foaming agent contributes to the expansion of the mortar mainly in the initial stage before hardening. The content of the foaming agent is preferably 0.001 to 0.003 parts by weight, more preferably 0.001 to 0.002 parts by weight, per 100 parts by weight of cement.

[0022] The admixtures that make up the non-shrinkage mortar may contain one or more of various admixtures that can generally be used with cement, such as antifoaming agents, water retention agents, shrinkage reducing agents, air-entraining agents, surfactants, water repellents, anti-efflorescence agents, and others.

[0023] The non-shrink mortar used in this embodiment contains cement and fine aggregate in addition to the above-mentioned admixtures. The content of the admixture is preferably 5 to 15 parts by weight, more preferably 8 to 10 parts by weight, per 100 parts by weight of cement. The content of the fine aggregate is preferably 80 to 200 parts by weight, more preferably 100 to 140 parts by weight, per 100 parts by weight of cement. The non-shrink mortar used in this embodiment may further contain water, and the content of water is preferably 30 to 50 parts by weight, more preferably 35 to 45 parts by weight, per 100 parts by weight of cement.

[0024] The cement is not particularly limited, and various types of Portland cement, such as ordinary, early-strength, extra-early-strength, or moderate-heat cement, blast-furnace cement, alumina cement, fly ash cement, phosphate cement, ecocement, and various types of blended cement can be used, and two or more of these may be used in the blend.Furthermore, the fine aggregate is not particularly limited in terms of whether it contains fine powder or its components, so long as it has a particle size of 5 mm or less, and examples include commonly used river sand, crushed stone, silica stone, silica sand, silica stone powder, limestone, slag aggregate, clinker aggregate, and various artificial aggregates.

[0025] Furthermore, as a non-shrinkage mortar, for example, one containing Portland cement preferably in a proportion of 15 to 35% by weight, more preferably 20 to 30% by weight, quartz preferably in a proportion of 35 to 55% by weight, more preferably 40 to 50% by weight, and calcium sulfate preferably in a proportion of 0.5 to 12% by weight, more preferably 1 to 10% by weight can be suitably used.

[0026] Next, water and non-shrinkage mortar are mixed, and then the required amount of aggregate is added to the ground mixer. and The paving material mixture is obtained by mixing them together (FIG. 1(C)). The aggregate is not particularly limited, but for example, aggregate with an average particle size of 3 to 6 mm (dry sieving method) can be used. Furthermore, from the viewpoint of enhancing the design, it is preferable to use natural stones (small particle size natural stones; those with a particle size smaller than the natural stones scattered on the surface of the pre-hardened mixture layer) as the aggregate.

[0027] In this embodiment, the mixing ratio of non-shrink mortar, aggregate, and water is preferably as follows: The amount of aggregate used per 100 parts by weight of non-shrink mortar is preferably 25 to 100 parts by weight, more preferably 35 to 75 parts by weight, and even more preferably 40 to 60 parts by weight. Furthermore, the amount of water used per 100 parts by weight of non-shrink mortar is preferably 10 to 30 parts by weight, more preferably 13 to 24 parts by weight, and even more preferably 15 to 22 parts by weight.

[0028] Furthermore, in order to enhance the design properties, coloring pigments and the like may be added to the paving material mixture obtained by mixing water, non-shrink mortar, and aggregate, if necessary.

[0029] Next, the paving material mixture obtained by mixing water, non-shrink mortar, and aggregate is poured onto the roadbed or subgrade to form a pre-hardening mixture layer (Fig. 1(D)). The thickness of the pre-hardening mixture layer is not particularly limited, and may be determined according to the thickness of the final natural stone-containing pavement.

[0030] Next, natural stones are scattered on the surface of the pre-hardening mixture layer formed on the roadbed or subgrade, so that some of the natural stones are exposed on the surface of the pre-hardening mixture layer and the rest are buried in the pre-hardening mixture layer (FIG. 1 (E)). As a result, the pre-hardening mixture layer hardens, and the natural stones are properly held on the natural stone-containing pavement surface, while some of them are exposed from the natural stone-containing pavement surface, thereby achieving a good design.

[0031] Natural stones can be selected appropriately depending on the design of the pavement containing natural stones to be obtained, but examples include Kashima gravel, Sanage, Oiso, and Beni. The amount of natural stones to be used also depends on the particle size of the natural stones to be used and the amount to be obtained. and The amount of the natural stone-containing pavement to be applied may be selected appropriately depending on the design of the pavement. For example, the amount of the natural stone-containing pavement to be applied to the surface of the pre-hardening mixture layer is preferably 5 to 15 kg / m. 2It is preferable to scatter the natural stones in an amount of 5 to 13 mm. The particle size of the natural stones is preferably 5 to 13 mm (dry sieving method).

[0032] Next, the pre-hardened mixture layer onto which natural stones have been scattered is subjected to surface preparation using a trowel or the like, if necessary. Adjustment After this (Fig. 1(F)), the surface is brushed and the mortar is removed from the surface (Fig. 1(G)), and then the pavement is allowed to harden to form a natural stone-containing pavement (Fig. 1(H)). The thickness of the natural stone-containing pavement is preferably 4 cm or more when used as a sidewalk or light traffic road, and 7 cm or more when used as a roadway or heavy traffic road. There is no particular upper limit to the thickness of the natural stone-containing pavement, but it is preferably 10 cm or less.

[0033] The natural stone-containing pavement obtained in this way is formed using a paving material mixture by mixing non-shrink mortar, aggregate, and water, and therefore has excellent compressive strength, flexural strength, and durability.Furthermore, the natural stones are properly held on the surface of the natural stone-containing pavement, and some of them are exposed from the surface of the natural stone-containing pavement, making it possible to achieve good design using the natural stones.

[0034] In addition, according to the natural stone-containing pavement of the present invention, a paving material mixture is obtained by mixing non-shrinkage mortar, aggregate, and water, and mixing can be done using a hand mixer or ground mixer, eliminating the need for construction machinery, thereby enabling the formation of natural stone-containing pavements with high productivity. Furthermore, according to the present invention, non-shrinkage mortar is used to obtain the paving material mixture, which allows the paving material mixture to be a premix-type mixture that can ensure sufficient usable time, and can ensure, for example, fluidity of about 4 to 8 (J14 funnel) seconds and a slump flow of about 55 to 66 cm, ensuring good workability.

[0035] Furthermore, in the present invention, the paving material mixture obtained by mixing non-shrinkage mortar, aggregate, and water can be applied at room temperature (5 to 35°C), does not emit carbon dioxide or other carbon dioxide gases during production and application, and does not produce an odor like bleached asphalt, thereby realizing a good roadside environment and working environment. [Example]

[0036] The present invention will be described below in more detail with reference to examples, but the present invention is not limited to these examples.

[0037] Example 1 First, 4.5 parts by weight of water was added to the ground mixer (Fig. 1(A)), followed by 25 parts by weight of ultra-fast hardening non-shrinkage mortar (trade name "Preyulux Super Type 10", manufactured by Pacific Materials Corporation) and mixed for 1.5 minutes (Fig. 1(B)). Next, 12.5 parts by weight of aggregate was added to the ground mixer and mixed for 1.0 minute (Fig. 1(C)), to obtain a paving material mixture.

[0038] The ultra-fast setting non-shrinkage mortar (trade name "Preu-Lox Super Type 10", manufactured by Pacific Materials Corporation) contains admixture, cement, and fine aggregate, with a Portland cement content of 20 to 30% by weight, a quartz content of 40 to 50% by weight, and a calcium sulfate content of 1 to 10% by weight. The ultra-fast setting non-shrinkage mortar (trade name "Preu-Lox Super Type 10", manufactured by Pacific Materials Corporation) is assumed to contain the above-mentioned specified amounts of admixture containing low-substituted hydroxypropyl cellulose and an expansive agent, cement, and fine aggregate.

[0039] The aggregate used was small-sized natural stone with a mean particle size of 3-6 mm (dry sieving method) and a passing mass percentage of 19.0 mm: 100.0%, 13.2 mm: 100%, 4.75 mm: 50-100%, 2.36 mm: 0%, 600 μm: 0%, 300 μm: 0%, 150 μm: 0%, and 75 μm: 0%. The resulting paving material mixture had excellent fluidity, with a flowability of 7 (J14 funnel) seconds measured in accordance with JSCE-F 541.

[0040] Next, a 30cm x 30cm x 5cm hardened specimen was prepared using the resulting pavement mixture. A bending test was conducted in accordance with the Pavement Inspection and Testing Method Handbook (B005), and the breaking strain (-10°C) was measured, resulting in a value of 4.4 (x 10 -3 ) was. The compressive strength and flexural strength were also measured. The results of the compressive strength and flexural strength measurements are shown in Figure 2. As is clear from Figure 2, the resulting paving material mixture was able to give a hardened product with excellent compressive strength and flexural strength. The compressive strength was measured in accordance with JIS A 1108 (dimensions: inner diameter 10 cm x height 20 cm), and the flexural strength was measured in accordance with JIS A 1106 (dimensions: length 40 cm x width 10 cm x height 10 cm).

[0041] The paving material mixture obtained above was poured onto a road surface measuring 4.5 m long x 2.4 m wide (temperature after application: 20°C) to form a pre-hardening mixture layer (Fig. 1 (D)). Next, natural stones were applied to the surface of the pre-hardening mixture layer at a rate of 10 kg / m 2After spraying the natural stone-containing pavement with a trowel (Fig. 1(E)), the surface was adjusted with a trowel (Fig. 1(F)), brushed, and the mortar removed (Fig. 1(G)). The pavement was then allowed to harden, forming a 10 cm thick natural stone-containing pavement. In this test, the road was reopened to traffic one hour after construction. As a result, even two years after construction, no damage to the natural stone-containing pavement was observed, demonstrating its excellent durability. In this test, natural stones with different average particle sizes were used (i.e., multiple types of natural stones with average particle sizes ranging from 5 to 13 mm (dry sieving method) were used), and multiple natural stone-containing pavements containing natural stones with different average particle sizes were formed. Figures 3(A) to 3(C) show examples of surface photographs of the natural stone-containing pavement formed in this test.

[0042] The resulting natural stone-containing pavement was also subjected to an aggregate scattering loss rate (torsion resistance test). The measurement results are shown in graph form in Figure 4, along with the results for Comparative Example 1, which will be described later. As shown in Figure 4, the natural stone-containing pavement of Example 1 had excellent torsion resistance. The aggregate scattering loss rate (torsion resistance test) was measured in accordance with the "Test method for aggregate scattering due to torsion" in the Pavement Survey and Testing Methods Handbook [Volume 3].

[0043] <Example 2> A paving material mixture and a natural stone-containing pavement were obtained in the same manner as in Example 1, except that an ultra-fast hardening non-shrinkage mortar (trade name "Preu Rocks Super" manufactured by Pacific Materials Co., Ltd.) was used instead of the ultra-fast hardening non-shrinkage mortar (trade name "Preu Rocks Super Type 10" manufactured by Pacific Materials Co., Ltd.), and evaluated in the same manner. It was confirmed that the same effects as in Example 1 were obtained.

[0044] <Comparative Example 1> A heated paving mixture was obtained by heating and mixing 6 parts by weight of a petroleum resin binder, 45 parts by weight of small-sized natural stones with an average particle size of 5-10 mm (dry sieving method), 44 parts by weight of natural sand with an average particle size of 0-2.5 mm (dry sieving method), and 5 parts by weight of stone powder in a commercial plant. The resulting paving mixture was spread evenly over a 4.5 m x 2.4 m road surface and compacted to form a 10 cm thick natural stone-containing pavement. Aggregate scattering loss rate (torsion resistance test) was performed in the same manner as in Example 1. The measurement results, along with those of Example 1, are graphed in Figure 4.

Claims

1. 1. A method for forming a natural stone-containing pavement, comprising: mixing non-shrink mortar, aggregate, and water to obtain a paving material mixture; pouring the paving material mixture onto a roadbed or subgrade to form a pre-hardened mixture layer; and scattering natural stones on the surface of the pre-hardening mixture layer. The thickness of the natural stone-containing pavement is 4 cm or more, and the particle size of the natural stone is 5 to 13 mm; The method for forming a natural stone-containing pavement, wherein the non-shrinkage mortar contains 20 to 30% by weight of Portland cement, 40 to 50% by weight of quartz, and 1 to 10% by weight of calcium sulfate.

2. 2. The method for forming a natural stone-containing pavement according to claim 1, wherein the non-shrinkage mortar contains an admixture containing low-substituted hydroxypropyl cellulose and an expansive material.

3. 3. The method for forming a natural stone-containing pavement according to claim 1, further comprising a step of hardening the pre-hardening mixture layer while leaving at least a portion of the natural stone exposed from the surface of the pre-hardening mixture layer.

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