JPH0332641B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a road surface regeneration method for existing asphalt pavement, which cracks due to long-term use or due to weathering or other causes.
This invention relates to a road surface regeneration method for asphalt pavement, which is characterized by treating and regenerating the surface layer or surface/base layer of asphalt pavement that has peeling, potholes, ruts, steps, irregularities, etc. on the road.

When the usability of asphalt pavement deteriorates after many years of use, various maintenance and repair methods are used depending on the degree of deterioration. When the damage is mild, seal coats, surface treatments, etc. are performed, but when the deterioration in serviceability becomes significant, overlays and even replacement are performed. Replacement involves the disposal of pavement waste, but it is difficult to secure a disposal site, and the pavement waste itself becomes a useful aggregate, so it is an effective way to conserve resources and save resources.
In terms of resource utilization, paving waste materials are being reused, and the amount is increasing significantly year by year.

There are two ways to reuse pavement waste: one is to recycle it into roadbed material, and the other is to recycle it into asphalt mixture. In both cases, a plant method and an on-road method (on-site method) are used.

The on-road method mainly involves heating the surface layer that is fatigued or has defects such as ruts, crushing it, mixing it, leveling it, and regenerating it by compacting it.
Furthermore, there is a method of regenerating by spreading a new heated asphalt mixture on top of it and rolling it, or by spreading a new heated asphalt mixture on the heated and crushed surface layer while mixing it and rolling it. Surface regeneration methods such as methods of regeneration, and roadbed regeneration where the surface layer and roadbed are scraped up, the crushed material is mixed with bitumen emulsion, cement, etc., spread, and compacted to create a regenerated roadbed, and the surface layer is applied on top of it. construction method is being implemented.

The construction method of the present invention relates to the road surface regeneration construction method described above.

Examples of asphalt pavement bodies to which the present invention is applied include the following.

Existing asphalt pavements with cracking, peeling, etc. due to aging on the surface layer, base layer, etc., or with rutting, etc., and are often found on local roads and municipal roads. Can be seen.
In these cases, the asphalt mixture that makes up the surface and base layers ages, the asphalt becomes hard due to lack of oil, and its bonding strength decreases, making the asphalt's function as a binder considerably lower than when it was first installed.

In addition, in areas with extremely low traffic volume after paving, some of the pavements deteriorate from the surface to the inside because they cannot be compacted by natural traffic. In addition, asphalt pavements using a heated asphalt mixture with high viscosity asphalt as a binder have cracks on the surface layer, and if the cracks are left untreated, they will crack further and peel. There are some things that may cause such problems.

In addition, by burying water, gas, etc. in urban areas, new paved areas that have been excavated and backfilled will continue to exist, as well as existing paved areas that have not been excavated and backfilled. In some cases, there are cracks in the existing pavement, or a difference in level between the two pavements.

The present invention aims to improve the durability of asphalt pavements that have reached their service limits or have worn-out surface layers, base layers, etc. by treating the asphalt mixture containing the surface layer, base layer, etc. at the site on the road. Regenerate on the surface layer with
The purpose is to regenerate asphalt pavement.

Then, the present invention cuts the surface layer or base layer of the asphalt pavement to a predetermined depth using a road milling machine or the like, and supplies the cutting material to a mix saver.
Additives such as asphalt emulsion are added to and mixed with the cutting material using a mix saver, and the mixture is spread evenly on the road surface.Then, the mixture is leveled by temporary rolling with rollers, the road surface is heated with a road heater, and the rollers are rolled again. The gist of this paper is a road surface regeneration method for asphalt pavement, which is characterized by compacting the asphalt pavement by compaction, and then applying a thin layer of asphalt pavement to the surface.

The asphalt pavement as used in the present invention is a pavement having a surface layer made of asphalt as a binder.
Therefore, not only asphalt pavement covered by the "Asphalt Pavement Guidelines" and "Simple Pavement Guidelines" published by the Japan Road Association, but also other asphalt pavements, such as light pavement and dust-proof pavement, etc. included.

That is, the asphalt pavement in the present invention includes expressways, general roads, airports, bridge surfaces, parking lots, factory premises, playgrounds, and other existing asphalt pavements.

The asphalt mixture for the surface layer and base layer of asphalt pavement is usually made of various types of asphalt (e.g., fine-grained ascon, dense-grained ascon, coarse-grained asphalt,
open grain asphalt, etc.), rolled asphalt, modified Topeka, Topeka, silica sand asphalt,
Heated asphalt mixtures such as goose asphalt, but other heated asphalt mixtures,
Also covered are aggregate and bituminous pavements formed by cold-applied bituminous mixtures, heated or cold surface treatments, and permeable macadam. Hereinafter, these will be collectively referred to as an asphalt mixture.

The road surface regeneration method of the present invention involves cutting asphalt mixture to a predetermined depth from the surface layer or base layer of an existing asphalt pavement on the road, regenerating the cut material on the road and paving, and applying a thin layer of asphalt to the surface. This involves paving, integrating and regenerating the pavement.

The outline of the construction method of the present invention is explained below using figures. The figure is a side view showing one example of the steps in the asphalt pavement road surface regeneration method of the present invention.

First, the surface layer or surface/base layer portion 1 of the existing asphalt pavement to be recycled is cut with a road milling machine 2. When cutting, the asphalt pavement surface may be heated using a road heater to soften it before cutting. Of course, it is not necessary to use a heater.
The cutting depth is usually 5 to 6 cm, but can be deeper. Up to 20cm for normal road milling machines
Cutting is possible to a certain extent. The road milling machine 2 includes a road planer, a heater planer,
Scarifiers, heater scarifiers, etc. can also be used. The cutting material cut by the road milling machine 2 is left in the shape of a ridge at the cut location.
The particle size of this cutting material varies depending on the type of asphalt mixture and cutting conditions. During cutting, depending on the depth of cutting, crushed stones and the like from the upper part of the roadbed may be mixed into the cutting material, but there is no problem even if such mixing occurs. It is also possible to supplement the cutting material with new aggregates (for example, crushed stone, sand, etc.).

This cutting material is continuously supplied to the mix spar 4 by the feed loader 3. The mix spaber 4 has a mixing mechanism that adds and mixes asphalt emulsion etc. to aggregate to create a mixture, and a mechanism that spreads the mixture to a uniform thickness on the road surface while applying vibration like an asphalt finisher. have. Some also have a tank or the like that can store an appropriate amount of additives such as asphalt emulsion. Generally, asphalt emulsion is supplied to mixer 4 from an asphalt emulsion tank truck using a hose.

In the mix spaber 4, a required amount of asphalt emulsion, etc. is continuously added to the cutting material that is continuously supplied to the mix spaber 4, mixed to form a mixture, and the mixture is spread evenly to a predetermined thickness. Advance. Following the spreading of this mixture,
The road surface is temporarily rolled with tire rollers 5 to level it. Then, the road surface is heated by the road surface heater 6. By this heating, the asphalt emulsion etc. added to the cutting material is spread well to every corner of the cutting material,
It fuses with the asphalt already contained in the cutting material (this is the asphalt of the asphalt mixture that formed the asphalt pavement, and has become hard due to its low oil content) and regenerates that asphalt.
At the same time, the water in the asphalt emulsion is evaporated. This moisture vapor prevents the asphalt from aging due to heating by the road heater 6. The spread cutting material mixture thus becomes a rejuvenated asphalt mixture. In addition, since it is heated, it is in a state where it can be compacted well by roller rolling pressure.

Then, it is sufficiently compacted using tire rollers 5 and iron wheel rollers (for example, macadam rollers, tandem rollers, etc.) 7.

After completion of this compaction, this compacted cutting material mixture can be core bored in the same way as ordinary ascon, and has sufficient stability.

Next, a new heated asphalt mixture 10 is spread on this surface using an asphalt finisher 8 from a dump truck 9, and a thin layer of asphalt pavement is constructed by rolling it with rollers, thereby completing the construction method of the present invention.

The asphalt emulsion used in the present invention is mainly an asphalt emulsion. In general,
Those that meet the JISK2208 petroleum asphalt emulsion standards are used, but those that do not meet these standards can also be used. For example, an emulsion having a penetration degree greater than that of the evaporation residue specified in the standard may also be used. Furthermore, asphalt to which heavy mineral oil, tar, etc. have been added, or rubber or elastomer to which it has been added can also be used. Types of emulsions generally include anionic, cationic, nonionic, and clay types, as well as permeation and mixing types, and any of them can be used.
Among these types, they are usually cationic or anionic, and are used for seepage or mixing coarse aggregate;
A class for mixing dense-grained aggregates is used. Even if the emulsion is not as good in mixability as those used for mixing soil asphalt or cement, it can be sufficiently mixed with the cutting material in the surface layer.

The amount of asphalt emulsion added to the cutting material varies depending on the thickness and properties of the surface layer or surface/base layer to be treated, pavement structure, pavement surface condition, traffic volume, weather conditions, etc., but the following amounts are standard: .

Normally, the asphalt mixture constituting the surface layer or the surface/base layer has an asphalt content of about 6% by weight when it is first manufactured, but after the pavement is put into service, it ages and this method is applied. The amount of asphalt is expected to be about 3 to 4% by weight of the mixture, and in order to obtain properties close to new materials by recycling, the amount of asphalt is insufficient, that is, about 2 to 4% by weight of the mixture. It is necessary to add 3% by weight of asphalt in the form of an asphalt emulsion. When using an asphalt emulsion obtained by emulsifying asphalt with heavy mineral oil (for example, process oil) added, or an asphalt emulsion with high penetration, the amount added can be reduced.

Moreover, cutback asphalt can also be used instead of asphalt emulsion.

When adding and mixing the asphalt emulsion to the cutting material, a small amount of cement can also be added. This addition helps improve the stability of the mixture.

The temperature of the mixture in the mixer 4 is
Although it varies depending on the temperature, it is around 40 to 50 degrees Celsius. The road surface made of the cutting material mixture temporarily rolled by the rollers 5 is preferably heated by the road surface heater 6 so that the temperature of the mixture rises to about 80°C. In this state, if the mixture is subjected to secondary rolling with rollers, the mixture is compacted very well, and the asphalt in the mixture is regenerated, so that it becomes like a new heated asphalt mixture. In addition, most of the water has evaporated, and the asphalt's binding strength to the aggregate is fully demonstrated.

The thin layer of asphalt pavement that is applied to the surface of the compacted mixture is usually asphalt pavement with a thickness of 3 cm or less, and heated asphalt mixture pavement is mainly used, but bituminous surface treatment at heating or room temperature is also possible. Can be used.

Next, the features, effects, etc. of the construction method of the present invention will be explained.

(1) Since road surface cutting is performed using a road surface milling machine, the particle size of the aggregate is uniform and cutting material containing no large lumps is obtained. Although it is a method, it can produce a uniform mixture, and it can be spread evenly and densely like an asphalt finisher.

(2) After preliminary compaction, water is removed by heating the road surface, and the asphalt contained in the conventional asphalt mixture and asphalt from the newly supplied asphalt emulsion are fused and regenerated. The compaction was also improved, and the initial stability was significantly improved, making it possible to collect cores in the same way as heated ascon. It has also become possible to perform quality control using cores, which was previously impossible with room-temperature mixtures.

(3) Cutting materials can be recycled like 100% heated ascon.

TA can be viewed in much the same way as Ascon.

(4) Good and easy construction.

(5) The finished surface will be smooth and the surface will be finished with little elevation.

(6) The cutting material mixture becomes similar to the heated mixture when the road surface is heated, so the water resistance of the finished pavement
Good durability. In addition, pavement with good stability can be obtained.

(7) Can be constructed even if the width is narrow.

(8) When regenerating a pavement excavated during underground burial work, etc., the surface and base layers of the pavement unrelated to the regeneration are regenerated using the construction method of the present invention, and the entire surface and base layer are regenerated using the construction method of the present invention. By applying thin layer pavement to the road surface, it is possible to obtain a pavement with a completely new finish with only a slight increase in height.

Example 1 An asphalt pavement with a surface layer of 6 cm thick and dense-grained asphalt concrete (maximum grain size 20 mm) with cracks on the surface was cut with a road milling machine to a depth of about 6 cm from the road surface. The temperature generated during cutting of the cutting material was approximately 45°C.

The cutting material is supplied to a mix spaber (manufactured by Sumitomo Heavy Industries) using a loader, and the cutting material is applied to the cutting material using the mix spaver. )
125) is added in an amount of 3 to 4% by weight, mixed to form a mixture, and the mixture is spread on the road surface to a thickness of about 7.5 cm. Next, after the tire rollers are used to temporarily roll the road and the road surface is leveled, the road surface is heated using a road heater. Then, it was sufficiently compacted by secondary compaction using a macadam roller and a tire roller. Furthermore, rubber-containing asphalt (rubber content: 4% by weight, penetration rate: 25
A heated asphalt mixture (60% by weight of asphalt,
(marshal stability 500Kg or more) is spread with an asphalt finisher at a mixture temperature of 140 to 150℃, compacted using tire rollers and macadam rollers, and a thin layer of asphalt pavement with a pressure of 2cm is constructed. The surface layer of asphalt pavement was regenerated on the road.

Table 1 Percentage of weight passed through sieve mm % 13 100 5 90~100 2.5 35~ 50 1.2 27~ 39 0.6 20~ 30 0.3 14~ 22 0.15 9~ 15 0.074 6~ 10 Recycled asphalt pavement is cored The results of the core's marshal test were also good. This pavement is in very good condition 6 months after construction.

[Brief explanation of the drawing]

The figure is a side view showing one example of the process of the asphalt pavement road surface regeneration method of the present invention. In the figure, 1 is the surface layer or surface/base layer part of the existing asphalt pavement to be regenerated, 2 is a road milling machine, 3 is a cutting material loading machine (feed loader), 4 is a mix spaber, 5 is a tire roller,
6 is a road heater, 7 is an iron wheel roller, 8 is an asphalt finisher, 9 is a dump truck, and 10 is a new heated asphalt mixture.

Claims (1)

[Claims] 1 Cut the surface layer or base layer of the asphalt pavement to a predetermined depth using a road milling machine, etc., supply the cutting material to a mix saver, and add and mix additives such as asphalt emulsion to the cut material in the mix saver. At the same time, spread the mixture on the road surface,
A road surface of an asphalt pavement body characterized in that the road surface is then temporarily compacted with rollers for alignment, the road surface is heated with a road heater, compacted by compaction again with rollers, and then a thin layer of asphalt pavement is applied to the surface. Surface regeneration method.