HU222688B1 - Method for renewal of asphalt rails - Google Patents

Abstract

During the process, the upper surface of the pavement is heated, loosened, picked up, homogenized by mixing on the spot, the mixture is returned to the road surface and applied to the layer layer of abrasive wall wear (6). The essence of the process is that at least a portion of the top layer of the road surface, such as the undercoat layer, preferably a bonding layer, is heated, loosened and picked up together with the top layer, and the mixture of the two materials is homogenized and optionally mixed with rejuvenating material or materials. on its disassembled surface, on which a layer of compressed surface asphalt, a wear layer (6), is applied together with the mixture acting as the returned layer (5). ŕ

Description

FIELD OF THE INVENTION The present invention relates to a method for reconstructing a multilayer asphalt pavement.

It is known that the wear layers of road asphalt pavements are primarily deformed due to the increasing traffic of heavy vehicles. The resulting deformations, especially treads, deformations, cracks, etc. resulting from general surface wear, increase the risk of accidents and require costly repairs.

Mostly, renovation work has been done by thickening the track structure by applying another layer or layers, especially if the load capacity of the track structure to be renovated has decreased over time.

Recently, so-called "on-site" hot recycling processes based on the reuse of part of the asphalt pavement of the road to be renovated are being used, whereby existing, damaged asphalt paving is heated, The material homogenized is returned to the road surface and compacted by rolling. This process provides significant savings in building materials, is relatively less disruptive to road traffic than conventional renovation methods, is environmentally acceptable, and the new wear layer meets the highest demands. In technical practice, such a solution, developed by WIRTGEN, has become known as REMIX (a technique called admixture of additional mineral and binder (s)).

Another version of the REMIX method is to apply and compress an additional thin top layer of asphalt onto this loose, re-blended and re-wetted wear layer. This process is known in the art as "REMIX-PLUS".

However, due to their original blend composition, the on-site hot recycling process was only possible during the renovation of the wear layer of aged sandstone asphalt by the addition of an additional asphalt mix suitable for reconditioning the binder and forming the crushed stone frame. This, of course, requires a large amount of additional transport and installation costs, and if the new thin surface asphalt layer mentioned above is to be reconstructed, two operation steps will be used. As a first step, the existing roughened sandstone layer is reconstructed with the aforementioned ADMIX technology, and the second step is to build the compacted layer to the desired type of abrasive layer, usually 3-4 cm thick for compactability. This type of renovation is technically sound but extremely costly.

SUMMARY OF THE INVENTION The object of the present invention is to provide a solution for the renovation of asphalt paved roads with a roughened sand asphalt wear layer, which technically provides a track structure of the same quality as the final product of the method described above, but at a significantly lower cost.

The invention is based on the discovery that the bonding layers beneath the crushed sandstone asphalt layers generally contain only crushed mineral material, with a relatively high content of mostly crushed stone. At the same time, their bitumen content is relatively low; As opposed to its binder content of 8%, it is only about 4-4.5% and of a softer type. Thus, when extending the loosening bonding layer to a softening binder layer when heating the casing, picking up and adding to the loosened and picked material of the sandblasting wear layer as necessary to form a proper composition, this bonding component is advantageously added to the loosened sand, the two "remixed" components will have the required composition and mechanical properties when mixed and homogenized. Thus, without additional supply of aggregate, it is possible to enter the amount of crushed stone required by the asphalt layer, reduce the original binder content of about 8%, and create a desired "top-layer" by applying a thin asphalt layer to the spread "remixed" material. , and with it, a high-quality, crack-free, refurbished casing is available.

Based on the above findings, the object of the present invention has been solved by a method of reconstructing a multilayer asphalt pavement comprising the top layer of natural sand in excess of 20% by weight and the sublayer layer in at least 65% by weight crushed mineral material, and comprising heating the upper surface of the road surface, loosening the top layer, picking up, homogenizing with mixing, returning the mixture to the road surface, applying a new asphalt wear layer to this returned layer and compacting the two layers together, heating, loosening and picking up at least a portion of the underlying layer of the road surface with the top layer and homogenizing and optionally rejuvenating the material or material by mixing the two materials together of the pavement, to which a new compacted asphalt layer is applied with this mixture.

In an embodiment of the process, at least 25 wt.%, Preferably about 50 to 100 wt.%, Of the material of the underlayer is blended with the loosened and picked up material of the top layer.

According to another aspect of the invention, 0.1 to 3.0% by weight of a hydrocarbon derivative, such as high-penetration bitumen and / or petroleum distillate and / or goudron, is added as a rejuvenating substance.

The process of the present invention will, of course, employ standard and well-known operations and operating parameters (e.g., shell heating, mixing, spreading temperatures, etc.), and may also use machines or machine chains known in REMIX technology.

HU 222 688 Β1

The invention will now be described in more detail with reference to the accompanying drawings, which include road sections illustrating how to carry out the method.

In the drawing, Figure 1 shows a section of a road 5 to be renovated;

Figure 2 illustrates an intermediate phase of the renovation process of the present invention;

Figure 3 is a cross-sectional view of the reconstructed roadway. 10

The cross-section of the roadway shown in Fig. 1 (shown only partially) may be constituted, for example, by a 20 cm thick cement-stabilized layer resting on a sand-gravel bed, on which is a 2-bit roadway of thickness a. A bonding layer 15 of thickness b is applied thereto, which is sealed by a wear layer 4 of roughened sand asphalt c having a thickness c. In this example, a is 10 cm, b is 5 cm and c is 4 cm. Since the base layer 1 and the bituminous pavement 2 are not dismantled during the renovation process of the present invention, these will not be further discussed. The bonding layer 3 is the K-20 type layer according to the relevant Hungarian standard, while the wearing layer 4 is the EHA-20 type layer.

The pavement of Figure 1 is reconstructed according to the present invention by the following technology: The casing is heated to 100-120 ° C by infrared gas burners on a mobile unit to soften the wear layer and the binder layer material. The power of the burners (individually) can be varied as a function of ambient temperature, depth of loosening and stiffness of the types of asphalt to be worked;

Thus, overheating of the binder can be safely avoided.

The next step involves loosening the heated and softened casing and dispensing the necessary rejuvenating material by means of a carbide tooth and a spreader device spirally disposed on a rotary milling roller of the mobile unit 35; the latter is intended for the administration of rejuvenating or / and binder.

The depth of the loosening roller is hydraulically adjustable and the depth of the set loosening is controlled by level control. The scraper plate behind the loosening roller collects the loosened material by moving it further into the mixing unit of the mobile unit.

According to the invention, not only the material of the wear layer 4 is removed in the manner described above, but also the portion b of the bonding layer 3 indicated by the reference numeral 3 'in FIG. 2, e.g. that is, k ”~ ^{c b} ~ 2 50 (The dashed lines in Fig. 2 also indicate the pre-burr layering.) The two components, i.e., high-sand sand wear and high-crushed / sand-sanded binder material, where we mix or re-mix. The "remixed" mixture is applied to the still warm surface F of the remaining portion b of the bonding layer 3, as shown in Figure 2, and a new asphalt mixture is applied to the laid material and then rolled in a single pass. This is how the roadway structure of Figure 3 is formed, with the returned layer 5 and the surface wear layer 6 being designated by reference numerals. It will be readily appreciated that hot and hot joints will be formed along adjacent layers F and f of the connector shown in Figure 3, i.e., the adhesion of the refurbished casing will be perfect.

The invention will now be described in more detail by way of examples. (The quality marks used in the examples correspond to those used in the relevant Hungarian standard.)

Example 1

An aged and somewhat deformed sandstone asphalt pavement road was renewed by the process of the present invention having a 3 cm layer of EHA-20 abrasive having the following average composition:

limestone flour natural sand crushed stone bitumen SZB 50 ~ 10% by weight ~ 50% by weight ~ 32% by weight ~ 8-8.5% by weight

The surface roughening of the wear layer was based on impregnated 16/20 crushed stone of 10 kg / m ² ; the amount of SZB-30 bitumen used for impregnation was 1.5% by weight.

The average composition of the K-20 asphalt binder under the wear layer was as follows:

limestone flour ~ 5 wt% natural sand ~ 15 wt% crushed sand and crushed stone ~ 75 wt%

Bitumen SZB-90 -4-4.5% by weight

With the technology described above on the basis of the figures, the entire sandstone asphalt layer and the upper layer of the bonding layer below, i.e., a fraction of the total amount of the wear layer, were loosened and picked up. Thus, 50-50% by weight of the components collected were mixed. The composition of the homogenized asphalt mixture was as follows:

limestone flour ~ 7 wt% natural sand ~ 30 wt% crushed stone / crushed sand ~ 57 wt% bitumen ~ 6 wt%

This mixture was returned to the disintegrated warm surface and sealed with a thin surface asphalt wear layer of 45 kg / m ² with the following composition:

limestone flour 10% by weight crushed stone 0/4 20% by weight crushed stone 5/8 27% by weight crushed stone 8/12 36,5% by weight

SBS Modified Bitumen 6.5% by weight

As said in the drawings, the two layers were compacted together to produce impeccably renovated road surfaces.

Example 2

The pavement is substantially identical to that shown in FIG. 1 in accordance with the present invention. The difference from Example 1 was that the EHA-20 is a hound

The thickness of the B1 layer was 4 cm and the degree of wear was higher than the former.

In view of the above, in this case, only a 2 cm region of the K-20 bonding layer underneath the EHA-20 wear layer was loosened and mixed ("remixed") with the material of the wear layer, i.e. 50% by weight of the latter. and an amount of B200 bitumen equal to 0.3% by weight of the mixture as a rejuvenator. The composition of the material homogenized by mixing was as follows:

limestone 8% by weight natural sand 35% by weight gravel / crushed sand 50% by weight bitumen 7% by weight The remixed mixture is returned to the remaining surface- needle and applied at a rate of 45 kg / m ² of asphalt wearing material of the following composition: limestone 12.0% by weight crushed stone 0/5 20.0% by weight crushed stone 5/8 30.0% by weight crushed stone 8/12 31.2% by weight SBS modified bitumen 6.8% by weight Even in this case, the two layers have been

b, as described above, creating a "hot is hot" bond between the layers.

Advantageous effects of the invention may be summarized as follows:

the process is extremely economical, as all that is needed is a new thin asphalt mixture, while the approx. 6 cm thick reconstructed, mixed and thus cracked layer forms the upper part of the track structure, which is of perfect quality and fully meets the requirements.

The invention is, of course, not limited to the exemplary embodiments of the process as detailed above, but may be practiced in various ways within the scope of the claims.

Claims (3)

PATENT CLAIMS A method of reconstructing a multilayer asphalt pavement with a natural top sand content of more than 20% by weight and a subsoil comprising at least 65% by weight of crushed mineral material, comprising heating the upper region of the pavement layer is recovered, picked up, homogenized by mixing, the mixture is returned to the road surface and a new asphalt wear layer (6) is applied to the returned layer (5) and the two layers are compacted together, characterized in that at least a part of the heating, loosening and picking up the top layer, and returning a mixture homogenized by mixing the two materials together, optionally supplemented with a rejuvenating substance or substances, to which the mixture is compacted we are applying a new layer of asphalt. Method according to Claim 1, characterized in that at least 25% by weight, preferably about 50-100% by weight, of the material of the underlayer layer is mixed with the loosened and picked up material of the top layer. 3. A process according to claim 1 or 2, wherein the rejuvenating agent is present in an amount of 0.1 to 3.0% by weight of the mixture, such as high-penetration bitumen or / and petroleum distillate, or / and goudron.