JP2020059650A - Paving mixture and production method thereof - Google Patents

Abstract

To provide a paving mixture capable of storing for a long period of time and developing strength equivalent to a hot asphalt mixture by heating and a production method thereof.SOLUTION: The paving mixture 10 contains an aggregate 11 and a coating layer 12 coating a surface of the aggregate 11. The coating layer 12 contains, from the inside, an asphalt layer 13, an adhesion layer 14, and a separation layer 15. The separation layer 15 is a layer formed by adding a demulsifier 19 to the asphalt emulsion 18.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a paving mixture and a method for producing the same, and more particularly, to a paving mixture that enables long-term storage and a method for producing the same.

  Generally, an asphalt mixture can be roughly classified into a hot asphalt mixture and a normal temperature asphalt mixture.

  The hot asphalt mixture is produced by mixing coarse aggregate, fine aggregate, filler and asphalt in a heated state. Specifically, the heated asphalt mixture produced in the production plant is heated and mixed with aggregates made of crushed stone, sand, filler, etc. and paving asphalt using a large asphalt mixing mixer installed in the plant. Manufactured. After that, the produced heated asphalt mixture is transported to a construction site while being kept warm, and is used for paving roads and ground surfaces, or for repairing them.

  In addition, the hot asphalt mixture includes those using new aggregates and those using recycled asphalt concrete aggregates. Asphalt concrete recycled aggregate is crushed and classified waste asphalt mixture generated by removal of existing pavement. In the following description, the recycled aggregate of asphalt concrete will be referred to as “recycled aggregate”.

  In some cases, the asphalt mixture for paving may be reused depending on the construction. In this case, apply heat to the construction site with a dedicated device, use a special device to produce an asphalt mixture for paving, or add the waste asphalt mixture to a dedicated device to heat it to produce a heated asphalt mixture. By manufacturing, it is used for paving roads and ground surfaces, or for repairing these.

  Furthermore, in the method for producing a storage asphalt mixture, a heating asphalt mixture produced in a general plant is used immediately after production using a dedicated facility, and a storage asphalt mixture produced by rapid cooling is applied. It is used for paving roads, ground surfaces, etc., or repairing them by heating them on site by an appropriate method.

  On the other hand, the room temperature asphalt mixture can be used for paving at room temperature (100 ° C. or lower) by mixing coarse aggregate, fine aggregate and the like with asphalt emulsion and the like at room temperature. The room temperature asphalt mixture is generally inferior in durability to the hot asphalt mixture, but since it can be stored, it is used as a simple paving material or repair material.

http: // www. askyo. JP / knowledge / 06-1. html (November 10, 2017) JP 2000-317434 A JP2012-126865A

  However, since the heated asphalt mixture produced in the plant is produced using a production apparatus such as a large-scale mixing mixer, the production amount per batch is at least several hundred kg. Therefore, in the case of small-scale paving or repair, the residual asphalt mixture for paving has to be discarded, which not only increases the cost but also has a problem in terms of environmental protection.

  Furthermore, it is necessary to strictly control the amount of shipment of the heated asphalt mixture from the plant, and the delivery time after the shipment until it arrives at the construction site. Furthermore, when construction was stopped due to sudden changes in weather, the entire amount of products manufactured had to be discarded. In any case, the heated asphalt mixture corresponds to an amount of paving asphalt mixture exceeding a certain amount, so it is economically difficult to install a plant in an area where demand is low, and the snowfall time, etc. There was a drawback that the plant could not be operated economically during the period when the demand for the plant was low.

  Furthermore, the heated asphalt mixture produced at the construction site does not generate waste asphalt mixture, but it is difficult to use for leveling correction, repair of potholes, ruts, etc., or small-scale new pavement. . In addition, it is costly and uneconomical to carry heavy equipment or special equipment for loosening or digging for small-scale pavement or repair of remote areas such as remote islands.

  In addition, the storage asphalt mixture is one that is constructed by melting the surface of the mixture by applying heat, but at high temperature, the petroleum asphalt for paving softens and this mixture blocks, and the mixture becomes a lump. There was a difficult problem in heating and melting. Further, petroleum asphalt for pavement belongs to a dry oil, and in particular, in long-term storage, it may deteriorate due to oxidation and may not obtain a predetermined performance.

  Furthermore, the above-mentioned preservation asphalt mixture is easy to produce by crushed stone of No. 6 crushed stone (4.75 mm to 13.2 mm) aggregate or No. 7 crushed stone (2.36 mm to 4.75 mm) aggregate. However, it is difficult to manufacture a fine aggregate having a diameter of 2.5 mm or less, and the lightweight aggregates do not separate from each other and form a lump. Further, it is difficult to produce various paving mixtures synthesized from No. 6 crushed stone aggregate, No. 7 crushed stone aggregate, fine aggregate and filler. Further, it is necessary to install dedicated equipment in the conventional plant for producing a petroleum asphalt mixture for paving, and it is not possible to simply manufacture.

  On the other hand, the room temperature asphalt mixture can be stored at room temperature, but it is premised that it is used as a simple paving material or repair material. Therefore, it is difficult to use the room temperature asphalt mixture as a substitute for the hot asphalt mixture.

  An object of the present invention based on the above problem is to provide a paving mixture that can be stored for a long period of time and has a strength equivalent to that of a heated asphalt mixture by heating, and a method for producing the same.

  The paving mixture of the present invention comprises an aggregate and a coating layer that coats the periphery of the aggregate, and the coating layer comprises an asphalt layer made of asphalt that coats the periphery of the aggregate, and the asphalt. Along with coating around the layer, an adhesive layer containing the asphalt, asphalt emulsion and demulsifier, and a separating layer covering the periphery of the adhesive layer and containing the demulsifier that has not reacted with the asphalt emulsion, It is characterized by having.

  The present invention provides a method for producing a pavement mixture in which an asphalt layer, an adhesive layer, and a separation layer are formed on the surface of the aggregate by mixing an aggregate, an asphalt, an asphalt emulsion, and a demulsifier. And, to the asphalt emulsion, by adding the demulsifier having a hydrogen ion concentration of a reaction equivalent or more and containing alcohol, to form the separation layer containing the demulsifier that has not reacted with the asphalt emulsion. It is characterized by doing.

  The paving mixture of the present invention comprises an aggregate and a coating layer that coats the periphery of the aggregate, and the coating layer comprises an asphalt layer made of asphalt that coats the periphery of the aggregate, and the asphalt. Along with coating around the layer, an adhesive layer containing the asphalt, asphalt emulsion and demulsifier, and a separating layer covering the periphery of the adhesive layer and containing the demulsifier that has not reacted with the asphalt emulsion, It is characterized by having. Therefore, in the outermost peripheral portion of the coating layer for coating the aggregate, since it has a separation layer containing a demulsifier that has not reacted with the asphalt emulsion, contact between the asphalt layer and the adhesive layer and the external atmosphere is suppressed, Oxidation of these layers is suppressed. Therefore, the paving mixture can be stored for a long time. Further, when the paving mixture is used for paving or repairing, the separation layer is evaporated by heating. Further, the asphalt layer and the adhesive layer are heated and melted to be integrated with each other to form a heat-melted asphalt layer, which has the same structure as that of the heated asphalt mixture and can be used as a so-called heating mixture. Therefore, the paving mixture of the present invention can be stored at room temperature for a long period of time like a room temperature asphalt mixture, and has sufficient strength like a heated asphalt mixture.

  The present invention provides a method for producing a pavement mixture in which an asphalt layer, an adhesive layer, and a separation layer are formed on the surface of the aggregate by mixing an aggregate, an asphalt, an asphalt emulsion, and a demulsifier. And, to the asphalt emulsion, by adding the demulsifier having a hydrogen ion concentration of a reaction equivalent or more and containing alcohol, to form the separation layer containing the demulsifier that has not reacted with the asphalt emulsion. It is characterized by doing. Therefore, it is possible to easily form the separation layer that prevents the asphalt layer and the adhesive layer formed around the aggregate from being oxidized. Further, in the method for producing a paving mixture according to the present invention, the separation layer is formed by adding the demulsifier having an alcohol having a hydrogen ion concentration of a reaction equivalent or more to the asphalt emulsion and containing alcohol. Characterize. Therefore, the water generated by adding the demulsifier containing the alcohol having a hydrogen ion concentration of the reaction equivalent or more, and the alcohol contained in the demulsifier are mixed, a separation layer having lubricity in the mixture of both. Can be generated.

It is a figure which shows the paving mixture which concerns on embodiment of this invention, (A) is sectional drawing which shows a paving mixture, (B) is the expanded sectional view. It is a figure which shows the paving mixture which concerns on embodiment of this invention, (A) and (B) are expanded sectional drawings of the paving mixture. It is a figure which shows the paving mixture which concerns on embodiment of this invention, (A) and (B) are expanded sectional drawings of the paving mixture. It is a figure which shows the paving mixture which concerns on embodiment of this invention, and is an expanded sectional view of a paving mixture. It is the flowchart which shows the manufacturing method of the paving mixture which uses the novel aggregate which relates to the form of execution of this invention, and the cross section diagram which shows the state of the paving mixture in each process. FIG. 3 is a flow chart showing a method for producing a paving mixture using the recycled aggregate according to the embodiment of the present invention, and a sectional view showing a state of the paving mixture in each step. It is a table which shows the physical property of the paving mixture which concerns on embodiment of this invention. It is a table which shows the result of having verified the physical property of the separated liquid formed on the surface of the paving mixture concerning an embodiment of the invention.

  Hereinafter, a paving mixture 10 according to an embodiment of the present invention and a method for manufacturing the same will be described in detail with reference to the drawings. In the following description, the same reference numerals will be used for the same members in principle, and repeated description will be omitted.

<Structure of Paving Mixture 10>
The structure of the paving mixture 10 will be described with reference to FIG. 1. FIG. 1 (A) is a sectional view showing the paving mixture 10, and FIG. 1 (B) is an enlarged sectional view thereof.

  With reference to FIG. 1 (A), the paving mixture 10 has an aggregate 11 and a coating layer 12 that covers the surface of the aggregate 11. As will be described later, the paving mixture 10 can be stored at room temperature for a long period of time, for example, in a state of being packed in a bag of several tens of kg. Further, the paving mixture 10 is heated to cause the coating layer 12 to melt and the paving mixture 10 to be adhered to each other, and the coating layer 12 is cured by cooling in the adhered state, so that high strength is obtained. Demonstrate. That is, the paving mixture 10 has excellent preservability like a room temperature asphalt mixture, and can obtain the same high strength as a hot asphalt mixture. The paving mixture 10 can be used in the construction or repair of roads or ground surfaces.

  The aggregate 11 is made of stone or the like adjusted to have a predetermined grain size. The particle size of the aggregate 11 is based on, for example, the “Pavement Construction Manual” defined by the Japan Road Association. The aggregate 11 is made of crushed stone, sand, filler and the like.

  The coating layer 12 covers the periphery of the aggregate 11. As will be described later, the coating layer 12 is produced by adding the asphalt emulsion 18 and the demulsifier 19 and the like to asphalt, and the oxidation thereof is suppressed even when stored for a long period of time.

  In FIG. 1 (B), a boundary enlarged sectional view of the paving mixture 10 is schematically shown. The coating layer 12 that covers the aggregate 11 has an asphalt layer 13, an adhesive layer 14, and a separation layer 15 from the inside. Further, the separation layer 15 which is the outermost layer of the coating layer 12 may be shared by the paving mixture 10 on the right side of the paper and the paving mixture 10 on the left side of the paper. Further, a contact point between the separation layer 15 of the paving mixture 10 on the right side of the paper and the separation layer 15 of the paving mixture 10 on the left side of the paper is shown by a dotted line (contact portion 17) on the paper.

  The asphalt layer 13 is a petroleum asphalt for paving, and it is also possible to employ a recycled asphalt obtained by adding a regeneration additive to the asphalt contained in the waste asphalt mixture discharged from the construction site. It is desirable to use, as the regeneration additive, for example, one that complies with the “Pavement Recycling Handbook” established by the Japan Road Association. Further, since the asphalt has already adhered to the periphery of the recycled aggregate, the asphalt content of the asphalt emulsion 18 to be added later can be changed so that the manufactured paving mixture 10 can be adjusted so as to fall within the standard of the amount of asphalt. , No additional asphalt input is required.

  The adhesive layer 14 is a layer produced by adding the asphalt emulsion 18 to the asphalt for paving forming the asphalt layer 13, and is a layer that exhibits an adhesive force. Here, the asphalt emulsion 18 is a petroleum asphalt cation emulsion (JIS K 2208) that is generally sold and used, or various petroleum asphalt cation emulsions that are commonly sold and used, or a petroleum asphalt amphoteric amphoteric having both polarities. Ionized emulsions can be employed.

  The separation layer 15 is a layer containing the demulsifier 19 which has not reacted with the asphalt emulsion 18 by adding the demulsifier 19 to the asphalt emulsion 18. Specifically, for example, the asphalt emulsion 18 is decomposed by adding and mixing a cationic asphalt emulsion 18 and a demulsifier 19 containing alcohol and having a hydrogen ion concentration higher than the reaction equivalent of the asphalt emulsion 18. While the asphalt particles 16 adhere to the similar asphalt layer 13, the decomposed water mixes with the unreacted demulsifier 19.

  The above-mentioned asphalt emulsion 18 is a petroleum asphalt cation emulsion, and is a cation emulsion that is generally sold and used (JIS K 2208) or various cation emulsions that are commonly sold and used, such as cationic ionic emulsions, bipolar A petroleum asphalt amphoteric ionized emulsion having properties can be adopted. Among the asphalt emulsions 18, an emulsion having an optimum asphalt content and asphalt penetration can be selected depending on the purpose of use and the degree of deterioration of the asphalt adhering to the recycled aggregate. Further, the asphalt emulsion 18 allows the asphalt physical properties of the final mixture to be adjusted to the physical properties of the asphalt within the desired specifications (penetration, softening point, elongation, etc.). When adjusting the amount of the asphalt emulsion 18, the water content of the asphalt emulsion 18 and the water content of the demulsifier 19 should be 2% or less of the total amount excluding the volatile components after the paving mixture 10 is produced. Is desirable.

  The above-mentioned demulsifier 19 is an aqueous solution having a hydrogen ion concentration of pH 11.0 or higher, which is at least one of alkali metal compounds or alkaline metal earth compounds, and has a flash point of 100 ° C. or higher and 170 ° C. or lower. At least one kind of a polyhydric alcohol or a trihydric alcohol having a flash point of 100 ° C. or higher and 170 ° C. or lower is added. The water decomposed from the asphalt emulsion 18 mixes with the demulsifier 19 and remains as the separation layer 15 having the lubricity of alcohol.

  The aqueous solution contained in the demulsifier 19 is preferably an aqueous solution of a relatively general-purpose compound such as sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, sodium metasilicate, and potassium metasilicate. Regarding sodium hydroxide and potassium hydroxide, an aqueous solution having a concentration of 5% or less, which is a general substance, is desirable.

  The alcohol contained in the demulsifier 19 has miscibility with viscous and high-boiling-point water used for lubricants, moisturizers, antifreezes, and the like, and specifically, ethylene glycol, diethylene glycol, propylene glycol, dipropylene. Glycol and glycerin are preferable.

  Since the amount of the demulsifier 19 added varies depending on the asphalt content and the hydrogen ion concentration of the asphalt emulsion 18 used, the water content of the asphalt emulsion 18 and the water content of the demulsifier 19 after the paving mixture 10 is formed. Adjust so that the amount of residual alcohol is 2% or less of the total amount of the mixture excluding volatile components, the hydrogen ion concentration is in the weak alkaline region of pH 8.0 or more and pH 11.0 or less, and the amount of residual alcohol is 1% or less of the total amount of the mixture. Is desirable. The adjustment for this can be easily performed by measuring the hydrogen ion concentration of the decomposed liquid by a beaker test in which the demulsifier 19 is added to the asphalt emulsion 18 to be used at a temperature of 100 ° C. or lower. Further, if the molar concentration of the asphalt emulsion 18 to be used is known, the molar concentration of the demulsifier 19 to be used can be calculated, and adjustment can be made by deriving an equimolar amount.

  The separation layer 15 is composed of, for example, 2% or less residual water content and 1% or less residual alcohol content, and the separation layer 15 in the weak alkaline region is 0.5% or more and 3% or less of the total amount of the paving mixture 10. Is desirable. Further, the separation layer 15 is a non-volatile material having repulsion of the same type of ions and lubricity of divalent and trivalent alcohols, and is not affected by pressure due to weighting or temperature change in a normal temperature range. Further, since the separation layer 15 exhibits weak alkalinity, oxidation of the adhesive layer 14 and the like is prevented and deterioration of the paving mixture 10 is suppressed, so that long-term stockpiling is possible.

  Furthermore, the separation layer 15 is a mixture of the above alkaline aqueous solution, alcohol, and water decomposed from the asphalt emulsion 18, and its pH is such that the aggregates 11 are solidified even when the paving mixture 10 is stored for a long period of time. By doing so, it is within a range in which the safety and hygiene environment of the worker who is involved in the production of the paving mixture 10 can be maintained without blocking. Specifically, the suitable range of pH of the separation layer 15 is, for example, 8.0 or more and 11.0 or less. The separation layer 15 having a pH of 8.0 or more can maintain the separated state of each aggregate 11, and the separation layer 15 having a pH of 11.0 or less can handle the paving mixture 10. The safety of members can be secured. Moreover, a particularly preferable range of the pH of the separation layer 15 is, for example, 9.0 or more and 10.0 or less. With such a range, the above-mentioned effects can be made remarkable.

  As described above, the paving mixture 10 has the separation layer 15 on the outermost periphery thereof, and the separation layer 15 is formed from the alkaline aqueous solution, alcohol, and water decomposed from the asphalt emulsion 18. Therefore, when the paving mixture 10 is stored, the quality of the paving mixture 10 is not affected by the pressure due to weighting, the temperature change in the normal temperature range, and the like. Further, since the separation layer 15 exhibits weak alkalinity, the asphalt layer 13 is prevented from being oxidized and deterioration of the paving mixture 10 is suppressed. Therefore, the pavement mixture 10 can be stored for a long period of time, and by heating and mixing at the construction site, it can be adapted to various pavements.

  Further, since the separation layer 15 is negatively charged, the separation layer 15 formed around the left aggregate 11 and the separation formed around the right aggregate 11 on the paper surface. Layers 15 repel each other. Therefore, even when the paving mixture 10 is stored in a storage bag for a long period of time, it is possible to prevent the paving mixture 10 from blocking.

  Furthermore, since the pavement mixture 10 can be stored in a bag for a long period of time, it is suitable for stockpiling for disasters, repairing and preparing for remote areas such as remote islands and roads during snowfall season when the plant is not in operation. Furthermore, by heating and mixing the paving mixture 10 by an appropriate method according to the situation of the site, it is possible to easily produce a petroleum asphalt mixture for paving in a particle size range that is in quality control and that complies with the standards of various places regarding paving. . Further, in an existing petroleum asphalt manufacturing plant for pavement, it can be generated relatively easily without adding equipment, and the materials to be used can be provided economically because they are general-purpose and easily available.

  Next, with reference to FIGS. 2 to 4, a reaction that occurs around the aggregate 11 when the paving mixture 10 is manufactured will be described. Each of FIGS. 2 to 4 is a cross-sectional view showing the boundary portion between the aggregates 11 in an enlarged manner.

  With reference to FIG. 2A, first, the surface of the aggregate 11 is covered with the asphalt layer 13. An asphalt emulsion 18 and a demulsifier 19 are present around the asphalt layer 13. Asphalt emulsion 18 contains asphalt particles 16 that are positively charged. As described above, the demulsifier 19 is alkaline because it has a hydrogen ion concentration equal to or higher than the reaction equivalent to the asphalt emulsion 18, and is negatively charged.

  Referring to FIG. 2B, next, the asphalt emulsion 18 and the demulsifier 19 are mixed with each other, whereby the asphalt emulsion 18 and the demulsifier 19 are mixed at the molecular level, and the asphalt particles contained in the asphalt emulsion 18 are mixed. 16 are electrically neutralized. Further, as described above, since the hydrogen ion concentration is higher than the reaction equivalent to the asphalt emulsion 18, the layer formed by mixing the asphalt emulsion 18 and the demulsifier 19 exhibits weak alkalinity.

  As described above with reference to FIG. 3A, since the asphalt particles 16 contained in the asphalt emulsion 18 are electrically neutralized, the asphalt particles 16 adhere to the surface of the similar asphalt layer 13. To do.

  As a result, as shown in FIG. 3B, an adhesive layer 14 made of asphalt particles 16 attached to the surface of the asphalt layer 13 is formed. Then, on the outside of the adhesive layer 14, a weakly alkaline separation layer 15 that is negatively charged is formed. Since the left-side separation layer 15 and the right-side separation layer 15 repel each other on the paper surface, the occurrence of blocking under the storage condition is suppressed.

  Referring to FIG. 4, when road construction or the like is performed using the paving mixture 10, the paving mixture 10 is heated with a burner or the like. As a result, the separation layer 15 described above evaporates. Further, the asphalt layer 13 and the adhesive layer 14 described above become an integrated hot-melt asphalt layer 20, and the hot-melt asphalt layer 20 bonds the paving mixture 10 to each other.

<Method for producing paving mixture 10>
Next, with reference to the flow charts of FIGS. 5 and 6, a method of manufacturing the paving mixture 10 having the above-described configuration will be described. A case where a new aggregate is adopted as the aggregate 11 will be described with reference to FIG. Further, a case where recycled aggregate is adopted as the aggregate 11 will be described with reference to FIG.

  With reference to FIG. 5, a method of manufacturing a paving mixture 10 using the novel aggregate of the present embodiment is a step S10 of mixing the aggregate 11 and asphalt, a step S11 of mixing the asphalt emulsion 18, and a separation layer. 15 in step S12. Further, the manufactured paving mixture 10 is stored in step S13, and the paving mixture 10 is used for construction in step S14. In this figure, next to each step, a schematic cross section of the aggregate 11 in that step is shown.

  In this step, it is not necessary to specially prepare a dedicated plant for producing the paving mixture 10 according to the present embodiment, and the paving mixture 10 is produced in a general-purpose plant for producing a heated asphalt mixture or a room temperature asphalt mixture. It can be manufactured.

  First, in step S10, the aggregate 11 and the asphalt are mixed. As the aggregate 11, as described above, a mixture of crushed stone, sand, and filler can be adopted. Actually, after the aggregate 11 having an appropriately adjusted particle size is dried and heated to an appropriate temperature, the aggregate 11 having a desired particle size range is put into a mixer, and the filler in the normal temperature range and the heated petroleum asphalt for paving are sequentially ordered. Add and mix. In this step, it is desirable that the temperature of the aggregate 11 is 100 ° C. or lower. Therefore, the dry aggregate 11 is used as much as possible, the drying heating temperature is adjusted, and the filler in the normal temperature range is heated to an appropriate temperature. Add and mix the pavement petroleum asphalt. By doing so, the equipment and the like are not loaded, and the mixture can be manufactured in a lubricated manner. The mixing in this step is performed, for example, under the condition that the temperature of each material is 80 ° C. or higher.

  In step S11, the asphalt emulsion 18 is added to and mixed with the mixture of the aggregate 11 and the asphalt layer 13. The types of the asphalt emulsion 18 are as described above. For example, a petroleum asphalt cation emulsion as the asphalt emulsion 18 is added at room temperature. By this step, the aggregate 11 is covered with the asphalt layer 13 and the asphalt emulsion 18. Here, when so-called new aggregate is adopted as the aggregate 11, step S10 of adhering asphalt around the new aggregate is essential, while when adopting recycled aggregate as the aggregate 11, step S10 is performed. It becomes unnecessary. This is because asphalt is already attached to the periphery of the recycled aggregate.

  In step S12, the demulsifier 19 is added to and mixed with the mixture of the aggregate 11, the asphalt layer 13, and the asphalt emulsion 18. The type and addition amount of the demulsifier 19 are as described above. For example, a demulsifier 19 of petroleum asphalt cation emulsion is added and mixed at room temperature in an appropriate amount. By this step, the aggregate 11 is covered with the asphalt layer 13, the asphalt emulsion 18 and the demulsifier 19. Here, the asphalt emulsion 18 and the demulsifier 19 can be charged and added from a charging port installed in the mixer part of the plant. Furthermore, asphalt additives and pigments that are usually used are also added in the same manner.

  Furthermore, by mixing the asphalt emulsion 18 and the demulsifier 19 in step S12, the reaction as described with reference to FIGS. 2 to 3 occurs, and the asphalt layer 13 and the adhesive layer 14 are formed on the surface of the aggregate 11. And the separation layer 15 comes to be formed. Here, the adhesive layer 14 can also be regarded as a decomposed asphalt layer after demulsification.

  Here, in the present embodiment, the demulsifier 19 containing an alcohol having a hydrogen ion concentration equal to or higher than the reaction equivalent to the asphalt emulsion 18 is added and mixed. By doing so, the asphalt emulsion 18 is decomposed, and the decomposed asphalt particles of the same kind adhere to the asphalt layer 13.

  Further, in this step, the preferable range of the pH of the separation layer 15 is, for example, 8.0 or more and 11.0 or less. The amount of the demulsifier 19 to be added is adjusted so that the pH of the separation layer 15 is in such a range. The separation layer 15 having a pH of 8.0 or more can maintain the separated state of each aggregate 11, and the separation layer 15 having a pH of 11.0 or less can handle the paving mixture 10. The safety of members can be secured. Moreover, a particularly preferable range of the pH of the separation layer 15 is, for example, 9.0 or more and 10.0 or less. With such a range, the above-mentioned effects can be made remarkable.

  In step S13, the paving mixture 10 manufactured by the above-described process is stored in a bag, for example, every several tens of kg. In the paving mixture 10 according to the present embodiment, since the separation layer 15 described above is formed on the surface thereof, blocking between the paving mixture 10 is suppressed and oxidation of the asphalt layer 13 and the like formed on the surface is prevented. It is prevented and can be stored for a long time.

  In step S14, the paving mixture 10 is used to construct roads, ground surfaces, and the like. Specifically, the paving mixture 10 is used after being heated to a predetermined temperature by an appropriate method at a construction site. For example, depending on the amount of the paving mixture 10 to be used, a method of heating and mixing with a hand burner that can be held in one hand and a small shovel, a method of heating and mixing with a propane gas burner having a diameter of about 80 mm to 100 mm and a scoop, or various Various construction methods can be adopted according to the situation of the site, such as a method of heating and mixing using a heating mixer for the construction site. Further, the temperature at the time of construction is the temperature at the time of laying the petroleum asphalt mixture for paving that has been conventionally performed, and it is generally desirable to be 110 ° C to 140 ° C. When the paving mixture 10 is heated in situ, the above-mentioned separation layer 15 evaporates by heating to form the hot-melt asphalt layer 20, as shown in FIG.

  A case where recycled aggregate is used as the aggregate 11 will be described with reference to FIG. The manufacturing method of the pavement mixture 10 using the recycled aggregate of the present embodiment includes a step S20 of adding a regeneration additive to the aggregate 11 and the recycled aggregate, a step S21 of mixing the asphalt emulsion 18, and a separation layer 15. And generating step S22. Further, the manufactured paving mixture 10 is stored in step S23, and the paving mixture 10 is used for construction in step S24.

  As described above, the manufacturing method of the paving mixture 10 herein is substantially the same as the manufacturing method described with reference to FIG. 5, and the difference is that the aggregate 11 which is the recycled aggregate in step S20. Is to regenerate the asphalt attached to the surrounding area.

  In step S20, the regenerated aggregate adjusted to the particle size of the aggregate 11 to be manufactured is dried and heated to an appropriate temperature in an arbitrary amount, and then put into a mixer and mixed with a regenerated additive. As the regeneration additive, for example, one that complies with the “Pavement Recycling Handbook” established by the Japan Road Association can be used. Further, since the asphalt has already adhered to the periphery of the recycled aggregate, the asphalt content of the asphalt emulsion 18 to be added later can be added so that the manufactured paving mixture 10 can be adjusted so as to meet the standard of the amount of asphalt. , No additional asphalt input is required. In this step, the oil component may be added to the recycled aggregate under a heated condition, or the oil component may be added to the recycled aggregate at room temperature. It is desirable that the temperature of the recycled aggregate is 100 ° C. or less, and by using the dried aggregate as dry as possible and adding an appropriate amount of the regeneration additive and mixing, the equipment can be manufactured in a lubricated manner without load.

  Details of step S21, step S22, step S23, and step S24 are the same as step S11, step S12, step S13, and step S14 described with reference to FIG.

  As described above, by adopting the recycled aggregate as the aggregate 11, it is possible to reduce the aggregate 11, asphalt and heat energy required for the method for manufacturing the paving mixture 10.

<Example>
With reference to the table of FIG. 7, it will be described that the hot-melt asphalt layer 20 of the paving mixture 10 according to the present embodiment described above satisfies the asphalt standard used for the hot-asphalt mixture. Here, the main items of the asphalt standard are penetration, softening point, elongation, flash point and density. Moreover, the appropriate range of each item is stipulated for general areas and general area heavy transportation.

  As described above, the present embodiment is an embodiment in which the paving mixture 10 is manufactured by using the new aggregate as the aggregate 11 and an embodiment in which the paving mixture 10 is manufactured by using the recycled aggregate as the aggregate 11. including. Therefore, the paving mixture 10 was manufactured using both embodiments, and the penetration, softening point, elongation, flash point and density of the hot-melt asphalt layer 20 thereof were measured. As a result, in both of the embodiments, the results satisfying most of the general area and general area multi-transportation items are obtained.

  From the above, the heat-melted asphalt layer 20 of the paving mixture 10 according to the present embodiment generally satisfies the asphalt standard regardless of whether the aggregate 11 is a new aggregate or a recycled aggregate. It can withstand the actual construction of the paving mixture 10.

  An example of the method for producing the paving mixture 10 described above will be described with reference to the table of FIG. Explaining the conditions of the examples, the ambient temperature was 25 ° C. and the molecular weight of sodium hydroxide was 40. Further, without using the aggregate 11, an asphalt emulsion 18, an aqueous solution of an alkaline compound contained in the demulsifier 19 (here, an aqueous sodium hydroxide solution), and an alcohol contained in the demulsifier 19 (here, ethylene glycol) are mixed in a beaker. By doing so, the asphalt emulsion 18 and the demulsifier 19 are separated into the asphalt component of the asphalt emulsion 18 corresponding to the adhesive layer 14 and the liquid corresponding to the separation layer 15, and the hydrogen ion concentration (pH) of the separated liquid Was measured. Then, the liquid was heated to 80 ° C. to 100 ° C. corresponding to the generation temperature of the paving mixture 10 and then cooled to room temperature, and the pH of the liquid was measured again. The liquid was cured at room temperature for 72 hours, and the pH of the liquid after curing was measured.

  Here, an ammonia-based emulsion is adopted as the asphalt emulsion 18, sodium hydroxide is adopted as the solute of the aqueous solution contained in the demulsifier 19, and the pH of the produced liquid is changed by changing the amount of the solute. . Further, here, five liquids were produced by changing the amount of solute, and the pH immediately after heating and cooling and the pH after curing for 72 hours were measured for each liquid. The reason why the pH was measured after 72 hours of curing was to confirm that the reaction had subsided and was stable.

  As shown in this figure, five samples, sample 1 to sample 5, are generated here. Sample 1 has the highest pH of the liquid produced by adding the most solute of the aqueous solution contained in the demulsifier 19. On the other hand, Sample 5 has the lowest pH of the liquid produced by adding the least amount of solute in the aqueous solution contained in the demulsifier 19. That is, as the number of samples increases, the amount of solute added decreases and the pH of the produced liquid decreases.

  Here, the sample 1 has a pH of 11.25 after 72 hours, and when such a sample is applied to the production of the paving mixture 10, the aggregates 11 can be well separated. However, if the pH is 11.25, the safety and health of the worker who handles the paving mixture 10 may not always be ensured.

  In Samples 2 and 3, the pH after 72 hours is 10.42 and 9.83, and when such a sample is applied to the production of the paving mixture 10, the aggregates 11 are well separated. be able to. Further, if the pH is within this range, the worker can safely handle the paving mixture 10.

  In Samples 4 and 5, the pH after 72 hours was 7.74 and 6.73, and when such samples were applied to the production of the paving mixture 10, the aggregates 11 were inadvertently adhered. There is blocking that occurs. Particularly, in the sample 5, the aggregates 11 come into close contact with each other. This is because the pH of the liquid generated as the separation layer 15 is close to neutral, and the repulsion rate of ions is low.

  From the above, the preferable range of pH of the separation layer 15 made of the produced liquid is 8.0 or more and 11.0 or less, and the particularly preferable pH range is 9.0 or more and 10.0 or less. I can understand that.

  Although the embodiment of the present invention has been described above, the present invention is not limited to this embodiment and can be modified within a range not departing from the object and gist of the present invention.

  For example, in the above description, when the paving mixture 10 was manufactured, the asphalt emulsion 18 was added and then the demulsifier 19 was added, but the order of addition may be reversed.

  Further, as the aggregate 11 used in the paving mixture 10, a mixture of new aggregate and recycled aggregate can be adopted.

10 Pavement Mixture 11 Aggregate 12 Covering Layer 13 Asphalt Layer 14 Adhesive Layer 15 Separation Layer 16 Asphalt Particles 17 Contact Area 18 Asphalt Emulsion 19 Demulsifier 20 Hot-melt Asphalt Layer

Claims (2)

An aggregate and a coating layer that covers the periphery of the aggregate,
The coating layer is
An asphalt layer made of asphalt covering the periphery of the aggregate,
An adhesive layer that covers the periphery of the asphalt layer and that includes the asphalt, the asphalt emulsion and the demulsifier,
A paving mixture, characterized in that it comprises a separating layer which covers the periphery of the adhesive layer and which contains a demulsifier which has not reacted with the asphalt emulsion. Aggregate, asphalt, asphalt emulsion, and by mixing a demulsifier, on the surface of the aggregate, asphalt layer, an adhesive layer, a method for producing a paving mixture to form a separation layer,
With respect to the asphalt emulsion, by adding the demulsifier having a hydrogen ion concentration of a reaction equivalent or more and containing alcohol, to form the separation layer containing the demulsifier that has not reacted with the asphalt emulsion. A method for producing a paving mixture, which is characterized.

Images