JPS6149447B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of regenerating an existing bituminous pavement by using the existing bituminous pavement as a roadbed.

The existing asphalt pavement is cracked and damaged.
As a method for regenerating asphalt pavement that has developed ruts, flow, or aged, bituminous emulsion and cement are added and mixed to the crushed asphalt mixture produced by cutting the pavement surface of the asphalt pavement with a road milling machine. There is a well-known method for reproducing it as a compacted roadbed by leveling it and reproducing it as a compacted roadbed. In addition, the surface layer, base layer, and subgrade of the asphalt pavement, or the subgrade below it, is cut and crushed with a stabilizer to a predetermined depth, and cement and bituminous emulsion are added to and mixed with the crushed material, and this is laid. Methods of leveling and regenerating as compacted roadbed are also known.

However, these conventionally known methods have extremely low construction efficiency because the process of cutting and crushing the existing bituminous pavement is separated from the process of adding bituminous emulsion and cement to the crushed material, mixing it, and spreading it. There are drawbacks. In addition, when mixing bituminous emulsion and cement with the crushed material, a predetermined amount of cement is spread on the flattened surface of the crushed material, the cement is mixed with the crushed material using a stabilizer, and then the bituminous emulsion is spread. However, a method has been adopted in which a bituminous emulsion is mixed into the crushed material mixed with cement using a stabilizer. However, there was a drawback that the scattering of pre-spread cement caused by wind etc. caused so-called dust pollution, which harmed agricultural crops, people and livestock along the road, and also harmed workers. Another drawback was that the bituminous emulsion and cement were not uniformly mixed in a constant ratio in the crushed material.

The purpose of the present invention is to compensate for and improve the above-mentioned drawbacks, and to apply a predetermined amount of bituminous emulsion and cement or lime or a combination of both on the surface layer of an existing bituminous pavement. A self-propelled road stabilizer or the like is used to cut and crush the top surface of the existing pavement to the roadbed or further to a predetermined depth in the roadbed while spraying a slurry-like composition consisting of (hereinafter collectively referred to as cement, etc.) At the same time, the mixture is mixed with a slurry-like composition consisting of cement, etc., and the resulting mixture is spread flat, and rollers, graders, etc. are used to compact the mixture and shape the surface of the mixture to form a recycled roadbed. This paper outlines a method for regenerating bituminous pavement, which is characterized by forming it, and then providing a new surface layer made of bituminous binder, aggregate, filler, etc. on the surface to unify the whole. It is something to do.

The present invention has appropriate waterproofness and flexibility because the cut and crushed material is uniformly mixed with bituminous emulsion and cement at a certain ratio, has a large supporting capacity, and is difficult to cause shrinkage cracks. To provide a pavement body having a reinforced recycled roadbed that can be easily and efficiently constructed, does not cause dust pollution from cement, etc., and greatly improves and eliminates the drawbacks seen in conventional known methods. was completed.

Next, embodiments of the present invention will be described.

The present invention can be widely applied to bituminous pavements of various structures, but preferably the total thickness of the pavement is about 5 to 80 cm,
The total thickness of the parts containing bituminous binder (surface layer, base layer, upper roadbed, etc.) is approximately 0.5 to 20.
cm, total thickness of parts that do not contain bituminous material (so-called roadbed parts such as upper and lower roadbeds made of gravel layer, granulated crushed stone layer, incised crushed stone layer, cement or lime stabilization layer, slag layer, etc.) It is suitable for application to pavements with a diameter of about 4.5 to 60 cm. Among these, when applied to pavements where the surface layer containing bituminous materials has a thickness of about 10 cm or less and the subgrade is not sufficiently reinforced, it is particularly suitable in terms of reinforcing and strengthening the subbase and construction efficiency. In addition, in cold regions, the total thickness of pavement, especially the thickness of the roadbed portion that does not contain bituminous binder, may be further increased to prevent frost heaving. go inside. In addition, the surface layer, base layer, or upper subgrade containing a bituminous binder is one made using a heated mixture for pavement, a room-temperature mixture, or a penetration method, etc., and the type of mixture, bituminous quality, etc. There are no particular restrictions on the type, properties, amount used, construction method, etc. of binders and aggregates.

The present invention applies the surface layer, base layer, and roadbed (upper layer roadbed) that make up the pavement to the surface of the existing bituminous pavement (generally, one that has a high cracking rate and needs to be replaced) as described above. A slurry is prepared by mixing a predetermined amount of bituminous emulsion and cement, etc., which are determined by testing based on the properties and thickness of the subgrade (lower roadbed), the thickness to which the present invention is applied, etc. Using a powerful self-propelled load stabilizer, etc., the existing bitumen is uniformly sprayed from a spray nozzle attached to a part of the cover/leveling device that covers the cutting, crushing, and mixing mechanism of the load stabilizer, etc. Cutting and crushing from the surface layer of the quality pavement to the subgrade, and in some cases even the subgrade, are carried out in one operation, and the crushed materials are mixed with cement, etc., and bituminous emulsion at the same time. , These mixtures are made uniformly and spread on their own using a self-propelled method, then they are rolled using tire rollers, the finished surface is shaped using a grader, and furthermore, tire rollers, iron wheel rollers, etc. are used in combination to thoroughly spread the mixture. After compacting, asphalt emulsion for curing (JIS K2208 PK-3) etc. is sprinkled on top of it as necessary, and the curing time required to develop the strength of cement etc. is taken to form a strong recycled roadbed. The recycled pavement of the present invention is completed by providing a new surface layer of any desired form, or a surface layer and a base layer, made of a bituminous binder, aggregate, filler, etc., by a conventional method on the surface.

The bituminous emulsion used in the present invention includes petroleum asphalt, natural asphalt, tars,
An emulsion whose main component is one or more bituminous substances selected from bituminous substances such as pithus.The type may be anionic, nonionic, or cationic, but it is not miscible with cement or lime. Use a material that has properties that do not significantly impede the development of strength due to hydraulic or air hardness. In addition, the standard bituminous emulsion has a concentration (evaporation residue) of 60% by weight and a penetration of evaporation residue of 40 to 300 at a temperature of 25℃, but the concentration depends on the water content of the material to be mixed. In consideration of the above, even if a higher concentration or a lower concentration is used, the amount equivalent to the predetermined amount at 60% by weight in terms of the amount of evaporation residue may be used. Incidentally, bituminous emulsions include those in which 0.5 to 10% by weight of one or a combination of rubbers or synthetic resins is added to the bituminous material to improve its properties. By using this kind of bituminous emulsion, the effects of the present invention can be further enhanced.

Examples of cement include Portland cement, blast furnace cement, silica cement, fly ash cement, blast furnace colloidal cement, colloidal cement, jet cement (used in combination with a setting regulator), alumina cement, sulfate-resistant cement, and expanded cement (which reacts with water). One or a combination of two or more selected from hydraulic cements such as those forming an Ettrin guide are used.

In addition, as lime, powder or granular slaked lime,
Use quicklime. In some cases, gypsum is used in combination with lime.

In the present invention, the above-mentioned bituminous emulsion and cement are uniformly mixed and supplied to a self-propelled road stabilizer as a slurry composition that is easy to flow. The proportion of the bituminous emulsion in the recycled roadbed is calculated by calculating the density of the finished recycled roadbed using 2.1, and the bituminous emulsion (converted to a concentration of 60% by weight) is 2 to 10% by weight, preferably 4 to 8.
% by weight, cement etc. 2-10% by weight, preferably
2.5 to 8% by weight, and the total amount of both is 4 to 8% by weight.
18% by weight, preferably in the range 6-14% by weight. Therefore, the composition of the slurry composition and its addition amount should be determined based on the properties of the excavated crushed material of the existing pavement, the expected physical properties of the reclaimed roadbed based on the excavation depth, and the load stabilizer. It is a necessary condition to adjust and decide by taking into account the speed of travel, etc.

As for the bituminous emulsion, if the amount thereof is less than 2% by weight, it cannot produce the effect of imparting waterproofness and flexibility to the recycled roadbed. In addition, if it exceeds 10% by weight, waterproofness and flexibility will improve, but the bituminous content mixed in the cut and crushed parts of the existing bituminous pavement included in the recycled roadbed will be added to this. As a result, the bituminous content becomes excessive, which not only causes a decrease in the strength such as the bearing capacity and flow resistance of the regenerated roadbed, but also makes it economically expensive, which is undesirable.

Regarding cement, etc., if the amount is less than 2% by weight, it will have no effect on the compressive strength of the recycled board, and if it exceeds 10% by weight (8% in the case of cement), the compressive strength will increase. This is undesirable because it causes the disadvantage that shrinkage cracks cannot be avoided. Among cement, etc., cement and lime are used, but in general, if the fine particles in the recycled roadbed contain a lot of sandy soil, cement is better, and silty soil or loamy soil is more likely to be used. If it is contained, it is recommended to use a combination of cement and lime or lime. In addition, if the subgrade soil always has a high water content, it is preferable to use quicklime or hydraulic cement forming ettringite in combination with general cement or lime.

Furthermore, when it comes to quantitative combinations of bituminous emulsion and cement, the appropriate combination proportions are determined by testing each time, taking into consideration the properties and economic efficiency of the material to which they will be added and the expected reclaimed roadbed. If the total amount is less than 4% by weight, the effects of the recycled roadbed expected by the present invention, namely, improved waterproofness, flexibility, and increased supporting capacity cannot be obtained. Also, 18% by weight
Exceeding this amount will not only be economically disadvantageous, but depending on the combination of the two, too much bituminous emulsion may cause a decrease in supporting capacity and flow phenomena, and may also cause problems with cement, etc. If the amount is too large, it is not preferable because it may cause shrinkage cracks.

In general, the preferred range of combinations is that if the amount of cement, etc. is combined at a ratio of 1 part by weight or less to 1 part by weight of bituminous emulsion (60% by weight of evaporation residue), shrinkage cracks will occur. It is particularly effective in preventing the occurrence of stress and improving stress relaxation properties such as flexibility. However, depending on the nature of the aggregate in the part of the pavement containing the bituminous material to be mixed, it is not necessarily necessary to be limited to this combination ratio.

In addition, a bituminous emulsion with a high water content may be added to the slurry composition formed by mixing the above-mentioned bituminous emulsion with cement, etc. in order to lower the viscosity and improve dispersibility, mixability, etc. Water may be used or water may be added separately. When using lime as cement, etc., the viscosity becomes high, so it is recommended to add an appropriate amount of water to lower the viscosity before use.

Next, the road stabilizer used in the present invention is a self-propelled type, and the thickness from the surface layer of the bituminous pavement to the roadbed, and if necessary to the subgrade soil, is approximately It has three functions: cutting, crushing, and mixing approximately 40 cm in one operation, and the function of spreading the mixed material evenly while self-propelled. It is necessary that the bituminous emulsion added thereto and the slurry composition made of cement, etc. can be uniformly mixed, and other equipment may be used as long as it has the same function. Good too.

Regarding the method of quantitatively supplying the slurry-like composition, it is poured into a tank installed on the load stabilizer, and from this tank a metering pump or the like installed on the load stabilizer is used to feed the slurry composition into a spraying device installed near the mixing mechanism. Even if the slurry composition is supplied continuously through a nozzle while self-propelled, the slurry composition may be poured into a tank loaded in another vehicle, and a rubber hose, etc., may be used to supply the above-mentioned metering pump or a part of the spraying device (a metering pump to another vehicle). If a pump is attached, the liquid may be connected to a pump (if one is installed), and the liquid may be continuously supplied while being self-propelled through a nozzle in the same manner as described above. The thickness of cutting, crushing and mixing by the road stabilizer is preferably about 40 cm from the surface of the existing bituminous pavement. If the thickness exceeds 40 cm, it will be difficult to compact the roadbed sufficiently in subsequent rolling operations to create a strong reclaimed roadbed with high density.

In implementing the present invention, the roadbed beneath the surface layer of the existing bituminous pavement is weak and requires reinforcement, or when so-called industrial waste (powder, (granular, small lump-like)
When using it as a roadbed material, etc., add an appropriate amount of new reinforcing aggregate (coarse aggregate, fine aggregate) on the surface layer of the existing bituminous pavement in advance and spread it. Alternatively, an appropriate amount of industrial waste may be used in combination with the aggregate.

In addition, if the roadbed, roadbed, etc. is too dry, slurry may be added to improve the mixability of these cuttings and crushed materials with other additives, and to improve the compaction of the mixture. It is advisable to carry out the work while spraying an appropriate amount of water together with the composition from a water sprinkler attached to a road stabilizer or the like.

Next, a new optional surface layer, or a base layer and a surface layer made of a bituminous binder, aggregate, filler, etc. to be provided on the recycled roadbed of the present invention, includes asphalts, tars, etc. as a binder. Add 0.5 to 20% by weight of one or more bituminous materials such as pithus, or add 0.5 to 20% by weight of natural or synthetic rubber, natural or thermoplastic synthetic resin, or their derivatives to these materials to improve their properties. Cutbacks include improved modified bituminous materials, filler-containing bituminous materials in which 3 to 40% by weight of organic or inorganic fine fillers are added to the above bituminous materials and modified bituminous materials, or the various bituminous materials listed above. A bituminous binder processed into a mold or emulsion type is used. As the aggregate and filler, ordinary crushed stone, artificial aggregate, gravel, stone powder, etc. of various particle sizes can be used. Then, surface treatment by heating or room temperature method (single layer type, two layer type, three layer type, etc.), slurry seal,
Thin-layer pavement (thickness 2.5cm or less), general pavement (coarse-grained,
Dense-grained, fine-grained, open-grained asphalt concrete or dense-grained, fine-grained gap-type asphalt concrete, etc.), anti-slip pavement, wear-resistant pavement, flow-resistant pavement, light-colored pavement, colored pavement, goose asphalt pavement, roll Pave a material selected from door asphalt pavement, semi-rigid pavement, oil-resistant pavement, water-permeable pavement, etc. In addition, as a special type, a binder (used in combination with a hardening agent) made of a modified bituminous material obtained by adding a thermosetting synthetic resin, such as an epoxy resin, to the above bituminous material, aggregate, and filler. Also included in the various types of surface layer or base layer and surface layer to be paved on the recycled roadbed of the present invention.

The effects of the present invention can be summarized as follows.

(1) Compared to conventional methods, the number of work steps is halved, greatly improving construction efficiency and significantly improving economic efficiency.

(2) The regenerated materials in the part of the existing bituminous pavement containing bituminous materials do not concentrate near the surface of the pavement as in the original invention, but form small lumps in the roadbed, subgrade soil, etc. In the original invention, it can be uniformly dispersed and treated with bituminous emulsion, cement, etc. together with other aggregates, etc., to transform into a composite new mixture, thereby forming a recycled roadbed. The negative effects caused by excessive bituminous content include a decrease in the supporting capacity against traffic loads, the flashing of bituminous materials oozing out during extremely hot weather, and the accompanying decrease in flow resistance and rutting phenomena. will not occur.

(3) By limiting the amount of cement, etc. and bituminous emulsion used in the recycled roadbed, as well as the total amount of both, shrinkage cracks will occur frequently, like in a roadbed stabilized with ordinary cement, lime, etc. It is possible to obtain a recycled roadbed that is free of oxidation and is more waterproof than a roadbed stabilized using only materials such as cement, has appropriate flexibility, and has a large supporting capacity and stress relaxation properties.
In turn, this has a great effect on extending the life of the newly installed surface layer on the reclaimed road surface.

(4) Cement and lime are mixed into the bituminous emulsion and added as a homogeneous and easily flowable slurry composition, so they cannot be blown away by wind as in the case of conventional cement addition. This will not cause any harm to crops, people or livestock along the road, or to workers.

Next, one example of implementation of the present invention will be described.

Example 1 An existing construction consisting of a sandy soil layer of about 5 cm, a gravel layer of about 13 cm, a grain-adjusted crushed stone layer of about 7 cm, and a dense-grained heated asphalt concrete layer of about 4 cm are sequentially laminated on a roadbed (loamy soil mixed with gravel). A self-propelled road stabilizer (manufactured by Sakai Heavy Industries, Ltd., Deep Stabilizer) is used on the surface of the bituminous pavement (with a crack rate of approximately 45%), and a hood ( (This also serves as a device for spreading the mixture evenly.) Using rubber hoses, the spraying device installed at the front position in the direction of travel and the slurry composition manufacturing device installed on another vehicle located ahead. Asphalt emulsion for cement mixing (evaporation residue 60% by weight,
A slurry composition made by uniformly mixing 100 parts by weight of evaporation residue (penetration of 87/25℃) and 60 parts by weight of ordinary Portland cement (the specific gravity of this slurry composition is 1.22, and the viscosity is as specified by the Japan Society of Civil Engineers). The flow ^time was 18 seconds using a J-funnel according to the draft guidelines for prepact concrete. Spraying at a rate of 34 kg, two vehicles are moved in parallel in the direction of travel, and a road stabilizer is used to cut and crush the existing bituminous pavement to a depth of approximately 20 cm below the surface, and remove the cut and crushed materials. While simultaneously mixing the slurry composition and the slurry composition in one operation, the mixture is continuously and uniformly spread using a spreading device installed in the hood of the road stabilizer. Next, this is compacted with tire rollers, the finished road surface is adjusted with a grader, and then thoroughly compacted using tire rollers and steel wheel rollers to form a strong solid material containing about 3% by weight of cement and about 5% by weight of asphalt emulsion. recycled roadbed (thickness approx. 20
form cm). Furthermore, asphalt emulsion (JIS K2208 PK-3) was sprinkled on the surface at a rate of 1/ ^m3 , and immediately after, No. 7 crushed stone was applied at a rate of ^{0.004m3/1m3 .}
After leveling and lightly compacting with a roller and applying a seal coat, the concrete was opened to traffic for three laps, and dense-grained heated asphalt concrete (maximum grain size 13 mm, finished thickness 4 cm) was applied on top using the usual method. A paving body was obtained by the method of the present invention.

Example 2 An existing construction consisting of a layer of cut crushed stone of about 20 cm, a layer of adjusted crushed stone of about 5 cm, a layer of coarse-grain heated asphalt concrete of about 5 cm, and a layer of dense-grain heated asphalt concrete of about 4 cm, successively laminated on the roadbed (loamy soil). Using a self-propelled road stabilizer similar to that used in Example 1, asphalt emulsion for cement mixing (trade name Assol) was applied to the surface of a bituminous pavement (crack rate approximately 40%) in the same manner as in Example 1. A, Nichirei Kagaku Kogyo Co., Ltd. product, evaporation residue 60% by weight, penetration of evaporation residue 90/25°C) 100 parts by weight mixed with 66 parts by weight of early strength Portland cement (specific gravity 1.23) , viscosity (J float flow time) 21 seconds) at an average rate of 32 kg per 1 m ² , the moving road stabilizer cuts and crushes the existing bituminous pavement to a depth of about 15 cm below the surface. The cutting, mixing of the crushed material and the slurry composition to be sprayed are performed simultaneously in one operation, and the mixture is continuously and uniformly spread by the movement of the load stabilizer, as described in Example 1 below. A strong recycled roadbed (about 15 cm thick) containing about 6% by weight of asphalt emulsion and about 4% by weight of cement is formed by processing in the same manner as above. Then,
1 m ² of asphalt emulsion (JIS K2208 PK-3)
Spread 0.8 per square meter and immediately apply coarse sand at 0.003 ^per square meter.
m ³ After leveling and applying a seal coat,
It was opened to traffic for three days, and the top surface was covered with dense-grained gap-type heated asphalt concrete (maximum grain size 13mm,
A paving body with a finished thickness of 4 cm) was paved in a conventional manner to obtain a paving body produced by the method of the present invention.

Example 3 An existing pavement (with a cracking rate of approx. Using the same self-propelled road stabilizer as in Example 1, 100 parts by weight of Assol A similar to that used in Example 2, 100 parts by weight of ordinary Portland cement and ¹ m2 of slurry composition made by mixing 17 parts by weight of water is 55 kg.
The road stabilizer moves from the surface of the existing bituminous pavement while dispersing it at an average rate of about 30%.
Cutting and crushing to a depth of less than 1.5 cm and mixing the cut and crushed material with a slurry composition are performed simultaneously in one operation, and the mixture is spread continuously and uniformly by the movement of the load stabilizer. A strong recycled roadbed (about 30 cm thick) containing about 4% by weight of asphalt emulsion (equivalent to 60% by weight of evaporation residue) and about 4% by weight of cement was prepared by the same method as in Example 1. Form. After applying a seal coat of asphalt emulsion and sand finish on the top surface as in Example 2 and opening it to traffic for one week, the top surface was further coated with asphalt emulsion and special cutback asphalt containing organic filler (product name:
A multilayer surface treatment layer (trade name: Rehabilitation Coat, product of Nichire Chemical Industry Co., Ltd., finished thickness approximately 1.3 cm) is formed by combining Ascol, a product of Nichire Chemical Industry Co., Ltd.) and aggregate, and the present invention A paving body was obtained using the method described above.

Example 4 Approximately 10 gravel layers on the roadbed (loamy soil mixed with gravel)
A slurry composition was suctioned and pumped onto the surface of an existing bituminous pavement (with a cracking rate of about 45%), which was made by successively laminating a layer of crushed stone with a particle size adjustment of about 7 cm and a layer of heated asphalt concrete with a dense particle size of about 4 cm. Asphalt emulsion for mixing special cement (evaporation residual 1 m ³ of a slurry composition prepared by adding and mixing 100 parts by weight of industrial slaked lime and 50 parts by weight of water to 100 parts by weight (60% by weight of evaporated residue, penetration of evaporation residue 85/25°C)
Cutting and crushing the existing bituminous pavement to a depth of approximately 25 cm from the surface of the existing bituminous pavement using a moving road stabilizer while distributing the material at an average rate of 66 kg per piece, and mixing the cut and crushed materials with the slurry composition. and 1
The mixture was continuously and uniformly spread by the transfer of the load stabilizer, and then treated in the same manner as in Example 1 to form an asphalt emulsion (60% by weight of evaporation residue) of about 5. % by weight, forming a strong recycled roadbed (approximately 25 cm thick) containing approximately 5% by weight of slaked lime. A seal coat of asphalt emulsion and coarse sand similar to that in Example 2 was applied to the top surface, and the surface was opened to traffic for one week. After that, a heated thin layer pavement with a thickness of 2.5 cm was further paved on the top surface using the usual method. A pavement body was obtained by the method of the present invention.

Claims (1)

[Claims] 1. While spraying a slurry composition consisting of a predetermined amount of bituminous emulsion and cement or lime or a combination of both onto the surface layer of the existing bituminous pavement, use a self-propelled road stabilizer etc. to remove the existing bituminous pavement. Cutting and crushing from the upper surface of the pavement to a predetermined depth in the roadbed or further into the roadbed and mixing the slurry composition are carried out at the same time, and the resulting mixture is spread flat, and the mixture is spread using rollers, graders, etc. A recycled roadbed is formed by compacting and shaping its surface, and then a bituminous binder and aggregate are added to the surface.
A method for regenerating bituminous pavement, characterized by providing a new optional surface layer made of filler, etc., and integrating the whole.