KR100720936B1 - Paving Method Using Used Asphalt Concrete - Google Patents

Abstract

The present invention relates to a method for paving a road by recycling aggregates contained in waste asphalt concrete as road pavement materials, specifically, a process of classifying aggregates of 40 mm or less by crushing waste ascon; Drying the sorted aggregate in a dry state; Analyze the asphalt content and particle size distribution of dried waste ascon aggregate to determine the amount of new asphalt to be added based on the mix design according to the Marshall method and also to determine the amount of new aggregate to be compared with the KS standard of aggregate. ; A step of producing recycled ascon by further mixing fresh asphalt and new aggregate determined to be added to the dried waste ascon aggregate in an electrical process; And it relates to a road paving method using waste ascon including the step of transporting reclaimed ascon to the field and laying in a conventional manner.

Description

Road Paving Method Using Waste Asphalt Concrete {Paving Method Using Used Asphalt Concrete}

1 is a cross-sectional view of the general waste ascon aggregate

Fig. 2 is a cross-sectional view of the cut asphalt asphalt aggregate.

※ Explanation of symbols about main part of drawing ※

10: aggregate

11: asphalt attached to the aggregate surface

12: Asphalt infiltrated into fine pores of aggregate

13: cutting surface of aggregate

The present invention relates to a method for paving roads by recycling aggregates contained in waste asphalt concrete as road pavement materials.

Asphalt concrete (hereinafter referred to as "ascon") is a mixture of asphalt and coarse aggregates, fine aggregates, and pavement fillers (limestone powder, cement, etc.) at room temperature or widely used in road paving and parking lots. However, as the traffic volume increases rapidly, the aging of Ascon paved roads is being accelerated.In the regions with high summer temperatures like in Korea, the unevenness of the road surface occurs due to the deep grooves in the Ascon paved roads due to the load of large vehicles. This may cause a lot of obstacles to the fast traffic of the vehicle.

As a result, KNOC has been continuously removing the old asphalt concrete pavement and reworking new asphalt concrete pavement or cutting the uneven road surface to make the road surface even. While the cost of doing this is enormous, on the other hand, the problem of disposal of the huge amount of waste ascon from the demolition or cutting operations (more than hundreds of thousands of tons per year) remains a more serious concern. As is well known, when the waste ascon is disposed on the ground or ground, the asphalt contained in the asphalt may be washed away to rainwater and contaminate groundwater and rivers, causing serious pollution problems.

On the other hand, if the recycled waste asphalt can be recycled, it can reduce the cost of pavement work in addition to solving the pollution problem, and also contribute to the preservation of natural aggregates by reducing the amount of new aggregates. It can also have a protective effect.

Looking at the waste ascon in more detail, when the aggregate is gathered by crushing the waste ascon, as shown in Figures 1 and 2, the asphalt 11 is attached to the surface of the aggregate 10, even the fine pores of the aggregate Asphalt has penetrated to (12). When the road surface is cut with a planarizer for the uniformity of the road surface, asphalt may not adhere to the cut surface 13 of the aggregate. However, considering all of these cases, the content of asphalt attached to the waste ascon aggregate is generally known to be about 5.5% of the total weight of the crushed waste ascon aggregate. As the specific gravity of asphalt is 1.02, and the specific gravity of aggregate is about 2.6, the weight and volume of asphalt and aggregate per tonne of crushed waste ascon aggregate are calculated as follows.

Weight of asphalt: 1ton x 5.5% = 55kg

Asphalt volume: 55㎏ / ton ÷ 1.02 ≒ 53.9ℓ

Aggregate weight: 1ton-55kg = 945kg

Volume of aggregate: 945 ÷ 2.6 ≒ 363.5ℓ

As shown above, the ratio of volume (volume) of pure asphalt to {53.9} over {363.5} TIMES 100 = 14.8% in waste ascon aggregate is very high. If it can be used, it can have a huge effect in terms of resource saving.

Therefore, there has been a lot of interest and research on the recycling of waste ascon rather than multi-disposal, and the government is aware of this, and is encouraging the recycling of waste ascon by devising 'Act on Resource Conservation and Promotion of Recycling'. However, although there is a lack of willingness to recycle resources in general, there is no satisfactory research result on this, and the recycling of waste ascon has not shown an exaggerated effect.

Conventional techniques proposed as a method for recycling waste asphalt asphalt aggregate, the method of pulverizing the waste asphalt asphalt and then mixed with the new aggregate heated and the like, and mixed with cut back asphalt or emulsified asphalt at room temperature without heating It is divided into two methods using a mixture of new aggregate and filler.

The method of heating and recycling waste ascon aggregate is to sort waste aggregates after crushing waste ascon, and to heat them to primarily soften the asphalt adhered to the aggregate, and then the asphalt softener and heated new ) Pavement work by adding additional aggregate and new asphalt. However, this method is not only expensive to prepare the heating equipment, but also when the aggregate classified in the waste ascon is heated, the asphalt contained in the aggregate burns, which can cause odor, and also when the softener is added, the surface of the aggregate Asphalt closely adhered to or absorbed in the aggregate is not softened, and the asphalt concrete recycled in this manner is very inferior in durability, and cracks are severely generated.

The method of mixing the waste ascon aggregate with new aggregate and new asphalt at room temperature is to add a cold-mix bituminous emulsion asphalt to the waste ascon recycled aggregate, using asphalt attached to the aggregate using a solvent. After dissolving, the solvent is evaporated away. However, this method is not suitable for general road pavement because of the high penetration of asphalt from recycled aggregates even when the solvent is evaporated, especially during winter (in the case of room temperature asphalt concrete using emulsion asphalt), It contains a lot of) As a result of the delay in the evaporation of asphalt moisture has a problem in that the construction is impossible in practical terms.

On the other hand, Patent No. 243926 for 'The method of manufacturing concrete for road pavement using crushed waste ascon' also relates to the method of using the waste ascon at room temperature, this patent technology is so that the emulsified asphalt is sufficiently coated on the surface of the crushed waste ascon aggregate This emulsified asphalt is to serve as an intermediate binder between the waste ascone recycled aggregate and the cement added thereafter. However, the method of this patent technique is somewhat complicated in that the use of the material is limited and the cement must be cured in the field because the additional material is limited to cement and the intermediate binder is limited to emulsified asphalt. In addition, there is a problem that the material cost is increased, and as a result, the recycling effect of the waste material is reduced.

The present invention has been made in order to improve the problems of the prior art as described above, an object of the present invention is to put recycled aggregate by adding RC or MC and brown asphalt or natural asphalt to the recycled aggregate of waste ascon with diluent In addition to softening the old asphalt attached to the at the same time, by using a low incidence asphalt, brown asphalt or natural asphalt to properly adjust the penetration of the asphalt, to solve the problems of the prior art that was impossible to construct at low temperatures.

The present invention is a step of crushing waste ascon to classify aggregate less than 40mm; Drying the sorted aggregate in a dry state; Analyze the asphalt content and particle size distribution of dried waste ascon aggregate to determine the amount of new asphalt to be added based on the mix design according to the Marshall method and also to determine the amount of new aggregate to be compared with the KS standard of aggregate. ; A step of producing recycled ascon by further mixing fresh asphalt and new aggregate determined to be added to the dried waste ascon aggregate in an electrical process; And it consists of five processes of transporting reclaimed ascon to the field and laying in a conventional manner.

Hereinafter, the present invention will be described in detail.

First step: grinding waste ascon to classify aggregate less than 40mm.

It is a process of sorting waste ascon and crushing only 40mm or less of aggregates crushed using 40mm sieve. As shown in Fig. 1, the waste ascon aggregate classified in this process is coated with asphalt on the surface of the waste ascon aggregate, in particular, the asphalt is penetrated into the micropores of the waste ascon aggregate and integrated with the aggregate. In this process, the waste ascon aggregate was classified by only 40mm or less. Considering that the asphalt is attached to the surface of the aggregate with a certain thickness, the size of the actual aggregate is less than 40mm.

2nd process: The process of drying the classified aggregate to air condition.

The sorted waste ascon aggregate contains a significant amount of moisture, so it is necessary to dry it to remove the moisture. If this moisture is not dried, the cut asphalt asphalt and brown asphalt (or natural asphalt) of MC or RC may not be in intimate contact with these asphalts in a subsequent process.

Step 3: Determining the amount of fresh asphalt and fresh aggregate to be added.

In this process, the asphalt content and particle size distribution of dried waste ascon aggregate are analyzed to determine the amount of new asphalt to be added based on the mix design according to the Marshall method, and the amount of new aggregate to be added in comparison with the KS standard of aggregate. Decide

Additional new asphalts include cutback asphalt RC or MC and brown asphalt or natural asphalt. Then, 1 part by weight of such fresh asphalt is mixed with 0.5-5 parts by weight of thinner, kerosene or diesel, or 0.5-5 parts by weight of a mixture of alcohol in these solvents (if necessary). The reason for using alcohol is not only to have no impact on the performance or quality of the asphalt, but also to increase the fluidity of the asphalt concrete and to allow the diluent to evaporate quickly.

In this process, brown asphalt or natural asphalt is diluted with a diluent, and the reason is that cutback asphalt has a high penetration even in a hardened state, so that the asphalt penetration with low penetration is appropriately adjusted. On the other hand, since the diluent used to melt brown asphalt or natural asphalt can lower the solidification temperature, increasing the amount of the diluent can solve the problem that construction was impossible due to the hardening of asphalt due to the winter temperature drop.

On the other hand, this process analyzes the particle size distribution of the waste ascon aggregate and compares with the KS standard to determine the amount of new aggregate corresponding to the difference with the KS standard.

4th step: The process of manufacturing recycled ascon by adding and mixing fresh asphalt and fresh aggregate determined in the electrical process.

In this step, the fresh asphalt and the new aggregate determined in the electrical process are added and mixed. The mixing may be performed by a conventional method such as using a batch mixer or a continuous mixer. In addition, in order to increase the strength of the aggregate and improve the quality of the packaging by increasing the bonding strength of the materials, asphalt admixtures such as ASA (Anti Stripping Agent), SBR Latex, SBS may be added. It is also possible to add reinforcing fibers in this process.

5th process: The process of laying the road by transporting ascon manufactured in the electric process to the site.

This process is a process of laying roads in a conventional manner using ascone produced in the electrical process. In other words, the manufactured ascon is transported to the site by a dump truck or the like, laid using a finisher or manpower, and compacted by a roller, etc., to complete the road.

Hereinafter, the present invention will be described based on Examples.

(Example 1)

A road 8m wide and 500m long was paved. The ground layer was laid using crushed waste ascon and the surface layer was prepared using ordinary ascon. The process applied to this example is as follows.

First step: The waste ascon was pulverized, and the crushed waste ascon was passed through a 40 mm sieve to classify and select only aggregates of 40 mm or less.

The second process: The selected aggregate of the electrical process was unfolded in air and dried in air so that most of the moisture contained in the waste ascon aggregate was evaporated.

The third process: random sampling and analysis of dried aggregate of electric process to grasp the aggregate particle size distribution and the amount of asphalt absorbed by the aggregate, and the type of new aggregate to be added in comparison with the determined aggregate particle size distribution and KS standard and The amount of aggregate was determined, and the formulation was designed according to the Marshall method to determine the amount of new asphalt to be added to and absorbed from the waste ascon aggregate.

The results of comparing the particle size distribution of crushed waste ascon aggregate and aggregate of KS standard are shown in Table 1 below. (The figures in the table below are the percentage of weight through the sieve)

Table 1

Check key 40 mm 19 mm #4 #8 # 50 # 200 Asphalt content Crushed Waste Ascon Aggregate 100 91.0 71-2 39.8 15.7 5.9 5.7 KS # 57 Aggregate Standard 90-100 90-100 23-53 15-41 4-16 0-6 -

As shown in the table above, as the particle size distribution of waste ascon is out of the upper limit of KS standard, KSF 2527 No. 57 aggregate (new aggregate) was supplemented to 30% of the total aggregate usage. The results of analyzing the particle size distribution of the aggregate after synthesis with ascon aggregate are shown in Table 2 below. (The figures in the table below are the percentage of weight through the sieve)

Table 2

division usage (%) 40 mm 19 mm #4 #8 # 50 # 200 Crushed Waste Ascon Aggregate 70 100 91.9 60.6 39.8 15.7 5.9 # 57 Aggregate Granularity 30 100 45.6 5.2 0.7 - - Total (synthetic granularity) 100 100 77.4 44.0 28.1 11.0 4.1 standard 90-100 56-80 23-53 15-41 4-16 0-6

As the synthetic aggregate, the amount of asphalt used was determined by mixing design according to the Marshall method. The amount of aggregate to be used was determined to be 8.5% including the asphalt contained in the waste ascon aggregate. As seen above, the amount of asphalt contained in the waste ascon aggregate was about 5.7% of the aggregate weight, so the amount of fresh asphalt added (8.5-5.7 = 2.8) was set to 2.8% of the aggregate weight.

As new asphalt to be added, MC-1 and brown asphalt in cutback asphalt were used in the same amount. That is, MC-1 and brown asphalt were each used 1.4% of the aggregate weight. However, 1.4% of the aggregate weight is used based on 50% of the brown asphalt solid content. As a diluent, a mixture of kerosene and methanol is used as a mixture of 1.4% of the aggregate weight (1.4% of kerosene and 1.4% of methanol).

Step 4: The new aggregate and new asphalt to be added in the electrical process were added to the crushed waste ascon aggregate and mixed using a mixer or the like. In this process, SBR Latex was added to improve the quality of the package. The amount of SBR Latex was 6kg based on 40% solids. The types and compounding amounts of materials mixed in this process are shown in Table 3 below.

Table 3

Material name Crushed Waste Ascon Aggregate # 57 sour aggregates asphalt SBR Latex system MC-1 Brown Asphalt (%) 65.7 28.1 2.8 2.8 0.6 100 Usage (kg) 657 281 28 28 6 1,000

The fifth step: Ascon manufactured in the electrical process was transported to the site by a dump truck according to a conventional method, installed in Hunisha, and compacted with six times of Macadam, eight tires, and six dams. Then, RC was sprayed 0.5 kg per m 2 on the top and 5 cm overlay of general asphalt (over lay) to form a surface layer.

Quality inspection was performed on the substrate laid by the present example. As a result, as shown in Table 4, it was confirmed that the substrate using the waste ascon aggregate according to the present example had a quality higher than the standard.

Table 4

division Compaction rate Stability Remarks Substrate of the present embodiment 97% 550 kg standard More than 96% 350 kg or more

The present invention is not only to contribute greatly to pollution prevention and recycling of resources by enabling the recycling of waste ascon aggregate, but also to be useful to increase the utilization of waste ascon aggregate by supplementing the disadvantages of the prior art.

Claims (4)

Grinding the waste ascon to classify the aggregate less than 40mm; Drying the sorted aggregate in a dry state; Asphalt content and particle size distribution were analyzed on the dried waste ascon aggregate to determine the amount of new asphalt used as cutback asphalt RC or MC and brown asphalt or natural asphalt, based on the formulation design according to Marshall method. A process of determining the amount of fresh aggregate to be added in comparison with the KS standard of aggregate by using 0.5-5 parts by weight of thinner, kerosene or diesel as a diluent per 1 part by weight of asphalt; A step of producing recycled ascon by further mixing fresh asphalt and new aggregate determined to be added to the dried waste ascon aggregate in an electrical process; And And the road paving method using the waste ascon including the step of transporting the recycled ascon to the field and laying in a conventional manner. delete The method of claim 1, wherein the light oil of the diluent is used as a mixture of light oil and alcohol. The road pavement using waste ascon according to claim 1 or 3, further comprising adding an asphalt admixture such as ASA (Anti Stripping Agent), SBR Latex, SBS when mixing waste ascon with fresh aggregate and fresh asphalt. Way.

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