KR101281969B1 - Modifier Composition for Low Carbon Warm Asphalt Mixture with Performance Grade of 64-22 or 70-22 Range and Manufacturing Method of Asphalt Mixture Using the Same - Google Patents

Abstract

The present invention relates to a modifier composition for a low carbon mesophilic type asphalt mixture expressing a common grade of PG 64-22 or PG 70-22, and a method for producing an asphalt mixture using the same, more specifically, 100 parts by weight of wax 4 In the modifier composition for low-carbon medium-temperature asphalt mixture, characterized in that the mixture is heated, melted, and mixed 4 ~ 30 parts by weight of the waste tire powder, and aggregate and asphalt, aggregate and filler material 94 It relates to a method for producing a low carbon mesophilic asphalt mixture, characterized in that ~ 96% by weight, asphalt and 4 to 6% by weight modifier are added and mixed in a plant mix. The low carbon mesophilic asphalt mixture according to the present invention enables the production of an effective mesophilic asphalt mixture (WMA) by a low carbon additive, and can reduce the heating energy required for the preparation of the mesophilic asphalt mixture, thereby reducing the amount of carbon dioxide which is the main culprit of global warming. It can significantly reduce the fuel consumption while minimizing the emission of other emulsifiers, and reduce the optimum mixing temperature and compaction temperature by about 15 ~ 25 ℃ compared to the prior art, resistance to high temperature plasticity change and low temperature cracking Common grades showing resistance express the performance of PG 64-22 or PG 70-22 and exhibit sufficient compaction.

Description

Modifier Composition for Low Carbon Warm Asphalt Mixture with Performance Grade of 64-22 or 70- 22 Range and Manufacturing Method of Asphalt Mixture Using the Same}

The present invention relates to a modifier composition for a low carbon mesothelial asphalt mixture expressing a common grade of PG 64-22 or PG 70-22 and a method for producing an asphalt mixture using the same.

As industrialization and urbanization progress in recent years, road construction is actively performed due to the demand for expansion of social infrastructure due to the rapid traffic increase, and about 90% of all pavement roads in Korea are asphalt pavement. According to 2006 data of Korea Ascon Cooperative, about 28.4 million tons of Ascon is consumed in Korea annually. As is well known, ascon is an abbreviation of "asphalt concrete" and variously aggregates having a predetermined size to meet the required physical properties of road pavement, and to combine them by thermal coating at high temperature using asphalt as a binder Manufacture. Asphalt, an aggregate binder, is a thermoplastic material that causes a phase change to a liquid state when a solid phase or heat is applied at room temperature.

Ascon uses the thermoplastic properties of these asphalt binders to heat aggregate and asphalt to homogeneously coat solid asphalt on the aggregate in a liquid state, and then compact and pack it at a minimum fluid holding temperature for the asphalt to act as a binder. It is a road pavement mixture using the principle of combining aggregate into solid phase, also called asphalt mixture.

In recent years, with the growing interest in the environment in pursuit of green growth, the reduction of carbon dioxide emission to prevent global warming has become an international concern. In addition to preventing global warming, this reduction in carbon dioxide emissions is drawing attention as it can create a commercial value of carbon credits. More than 400 million tons of carbon credits were traded in 2006 at the European Climate Exchange in Amsterdam, the world's largest city, with more than 50% carbon trading volume increasing each year, increasing interest in carbon credits. It is becoming.

Ascon (asphalt concrete; asphalt mixture) paving technology has been actively studied to reduce carbon dioxide emission in accordance with such atmosphere. Among them, the most attention in terms of practicality and scale is the field of road pavement technology using a low carbon type asphalt mixture that can lower the mixing and compaction temperature during asphalt concrete pavement construction.

The first use of asphalt, a binder of asphalt mixtures, was the first in the late 19th century, Trinidad Lake Asphalt, a natural asphalt from Trinidad in South America, and currently uses petroleum asphalt produced from crude oil that can be mass-produced at home and abroad. Asphalt is composed of aliphatic hydrocarbons, asphaltenes, resins and aromatic hydrocarbons, and the physical-chemical properties of the asphalt are different depending on the origin of the crude oil.

Asphalt quality grades are mainly classified by viscosity, classification by asphalt intrusion degree or oxidation viscosity. In Korea, AP-3 (intrusion degree = 85 ~ 100, KS) is adopted by classification method by asphalt penetration degree. M 2252), producing and using asphalt grades AP-5 (infiltration = 60-70). As such, the coating amount of the asphalt aggregate is very important in thermal coating the aggregate using the thermoplastic properties of the asphalt. If the asphalt content is more than the appropriate amount of aggregate, excessive asphalt is press-bleeded to the surface when paving the road, causing the problem of asphalt alone fine layer forming (Flushing) on the surface of the aggregate, thereby increasing the plasticity of the package As it cannot endure the load applied to the vehicle, it causes so-called plastic deformation (Rutting), causing unevenness of the road surface, which causes many problems for traffic safety. As a result, the aggregate is detached and the surface of the road becomes uneven, causing many problems in traffic safety.

Therefore, the mixing temperature is very important for coating the optimum content of asphalt for the aggregate. According to domestic and international academic research papers and the Ministry of Construction and Transportation's "Design Guidelines for Mixing Heated Asphalt Mixtures" in 2005, the optimum homogeneous coating is achieved when the asphalt viscosity is 150 to 300 cps, and the compaction is best at 300 to 400 cps. Is being reported. As a result, the temperature control in the Ascon plant normally operates the temperature of about 150 ~ 190 ℃ when preparing the asphalt mixture using AP-5 asphalt, and the compaction temperature of the asphalt mixture thus prepared is operated at 130 ~ 160 ℃. to be.

Typically, the asphalt mixture is prepared by adding asphalt, aggregate, filler, etc. to an asphalt mixing plant, and then heating and mixing these materials. The asphalt mixture is manufactured through a process of heating to a high temperature of 160 ~ 200 ℃, is cooled to room temperature in the process of laying and compacting on the road. The reason why the high temperature heating process is required for the production of the asphalt mixture is because it is necessary to liquefy the asphalt (Asphalt) to act as a binder of the aggregate.

In other words, asphalt used mainly for paving roads is petroleum-based asphalt, and such petroleum-based asphalt (mainly straight asphalt is used as a asphalt binder) is a black solid in the manufacturing process. Are manufactured. Asphalt (Asphalt) is heated to liquefy and use the adhesive force of the liquefied asphalt for bonding the aggregate. Thus, the asphalt mixture used for pavement is made of a hot asphalt mixture (Hot-Mix Asphalt Mixture, simply referred to as 'HMA').

Therefore, a lot of energy is required to heat the asphalt mixture to a high temperature for the production of asphalt mixture, and there is a problem that the emissions of harmful gases such as carbon dioxide (CO ₂ ) increases even during the construction of the asphalt mixture. In addition, the high-temperature asphalt mixture laid and compacted during pavement has a problem that workers are exposed to the risk of safety accidents along with the problem that the traffic opening time is delayed by the time required to cool near room temperature.

Recently, in order to solve these problems, Warm-Mix Asphalt Mixture (WMA), which can be mixed and compacted at a lower temperature than conventional heated asphalt mixture (HMA) by lowering the temperature sensitivity of the asphalt (called temperature sensitivity) Research is being actively conducted. In other words, research is being actively conducted to reduce carbon dioxide emissions due to asphalt mixture pavement by lowering the mixing and compaction temperature of asphalt and aggregate. Road paving technology using such a medium temperature asphalt mixture (WMA) is 110 ~ 150 ℃ temperature 30 ~ 40 ℃ lower than the temperature required to prepare the asphalt mixture compared to the conventional road paving technology by heated asphalt mixture (HMA) Since the asphalt mixture can be produced in (1) it can suppress the generation of various harmful gases during the production and construction of the asphalt mixture, and (2) about 30% of the petroleum-based fuel that is the main culprit of the greenhouse gas during the asphalt mixture production process. It can reduce the speed, (3) shorten the curing time after construction of the asphalt mixture, and open up the traffic quickly. (4) No harmful vapor or odor is generated at the construction site. Has

The core mechanism of this medium-temperature asphalt mixture (WMA) paving technology is to improve the fluidity of asphalt, that is, the optimum viscosity of asphalt, which is a binder of aggregate, is expressed at a temperature as low as possible than the heated asphalt mixture (HMA), and also the optimum compaction degree. (Compaction Rate) It is a technique of lowering the viscosity to be expressed at a low temperature. This viscosity-lowering technique was first introduced in 1956 by Dr. Ladis H.Csanyl of the University of Iowa, USA, by injecting steam into the asphalt to form a foamed asphalt with moisture and air in the asphalt to lower the viscosity by reducing the stress inside the asphalt. I introduced the technology.

Recently, since 2000, Europe has been injecting water instead of steam and forced emulsification of asphalt to lower the viscosity of asphalt, and zeolite instead of water. The technology has been developed to produce a foam-medium asphalt mixture (Foam-WMA) that emulsifies the asphalt as the water moistened in the asphalt is discharged.

Meanwhile, since 2005, a medium temperature asphalt mixture (WMA) using Sasobit wax manufactured by Waxes, ie, Fischer Tropsch Synthesis, has been reported at the National Center for Asphalt Technology (NCAT). Normally, wax is a compound of several hundreds of molecular weight which is solid at room temperature and turns into a fluid when the temperature is increased. Such wax is added to asphalt to drastically reduce the viscosity of the asphalt above the melting temperature of the wax, and to solidify below the melting temperature. As a result, it is used as an additive to enhance the efficacy of mesophilic asphalt mixtures. The polyethylene wax may be a wax produced as a by-product during the manufacture or processing of polyethylene. In particular, the sasobit wax may be a Fischer Tropsch Synthesis method among polyethylene waxes. Polyethylene wax produced.

There are three methods for producing such a polyethylene wax.

(1) obtain polyethylene wax from low molecular weight by-products from the process of making polyethylene resin, or (2) produce polyethylene wax by thermal decomposition of polyethylene resin to reduce molecular weight, or (3) Fischer Tropsch synthesis).

In general, it is known that the physical properties of polyethylene waxes are determined by the linearity and molecular weight of the main chain in the chemical structure. In other words, the greater the linearity of the main chain of polyethylene wax, the higher the molecular regularity, the higher the crystallinity, the higher the physical properties such as melting point and hardness, and the higher the molecular weight of the polyethylene wax, the higher the melt viscosity and physical properties. It is known that it can be done.

As a result, polyethylene waxes obtained by pyrolysis of by-products or polyethylene resins in the process of making polyethylene resins have a lower melt linearity compared to polyethylene waxes produced by the Fischer Ropsch process to improve physical properties. The use as an additive in asphalt mixtures (WMA) has been limited.

However, Sasobit wax manufactured by Fischer Tropsch Synthesis process has more than 90% of its normal alkanes, so compared to other waxes produced by other methods. Has a long linear structure (Long Chin Aliphatic Hydrocarbon). Therefore, Sasobit wax shows better physical properties as a low carbon additive than other polyethylene waxes. Thus, Sasobit wax prepared by Fischer Tropsch Synthesis process has been used as a very effective low carbon additive in mesophilic asphalt mixtures.

However, polyethylene waxes such as Sasobit wax have very high temperature characteristics such as resistance to plastic deformation (Rutting, Permanent Deformation), while the stiffness increases and the stiffness change rate of asphalt after prolonged aging. As m-value is decreased, the low temperature property of asphalt is lowered as the elasticity of asphalt is lowered.

 Accordingly, the conventional polyethylene wax is a low temperature crack of the asphalt mixture, which occurs mainly in winter, and is generated from the top of the pavement layer due to an unbalance of the temperature distribution of the pavement layer due to the asphalt mixture. There is a problem that there is a high possibility of acting as a factor causing the lateral characteristics of the pavement), there is a need to improve the problem of low temperature properties in the medium temperature asphalt mixture (WMA) using polyethylene wax as an additive.

In addition, the existing ascon is difficult to install because the composition is hardened when the temperature of the ascon decreases when a narrow and congested pavement is applied. (If the moving distance is far) It is difficult to secure a predetermined laying and construction temperature. In addition, it is difficult to secure the compaction time during the construction of cold climates or during emergency repair work in cold weather, so it is impossible to overcome the temperature reduction due to the waiting time. Above all, a large amount of fuel is consumed due to high temperature manufacturing and construction, and excessive carbon dioxide is emitted. It has a problem.

Due to the problems of manufacturing and constructability, existing asphalt mixtures were not able to exhibit the durability and durability of guaranteed durability, so that they did not meet the road conditions and were often damaged or deformed. In addition, the cooling time is prolonged due to the high temperature manufacturing and construction, the traffic opening time is increased during construction of the traffic congestion section, causing frequent complaints, and in the case of manufacturing modified asphalt mixture or special functional asphalt mixture as well as general asphalt mixture manufacturing and construction process. Because of the higher processing temperatures required, excessive fuel waste (traditional asphalt mixtures heated above 160 ° C consumes 7 to 10 liters of heavy oil per tonne) and excessive carbon dioxide emissions contribute to atmospheric pollution.

In particular, the existing asphalt mixture is difficult to install itself because the temperature of the product is lowered below the appropriate temperature during the installation waiting time during the installation or repair work in cold climate, and even if it is laid, the durability and functionality of the pavement surface is significantly reduced. In addition, existing asphalt mixtures are paved without considering road conditions in different environments, causing plastic deformation and mass breakage of the heavy vehicles, as well as vehicle running noise on roads adjacent to residential areas. It has a large number of complaints and causes problems such as glare caused by rainwater during the night and rain, and a slip accident caused by water film formation.

Therefore, the present inventors are trying to develop a modifier composition for mesophilic asphalt mixtures applicable to PG 64-22, 70-22 common grades, and the composition of slaked lime and waste tire powder on the wax is used to improve the mesophilic asphalt mixture. The present invention was completed by confirming that greatly improved.

An object of the present invention is to release a lot of harmful substances such as carbon dioxide during the road construction in the conventional HMA or WMA, to solve a lot of energy requirements, the optimum mixing temperature and compaction temperature is about 15 ~ 25 ℃ lower than the conventional HMA It is to provide a modifier composition for a low-carbon, medium-temperature asphalt mixture capable of securing PG 64-22, 70-22 common grade.

Still another object of the present invention is to provide a method for preparing an asphalt mixture using the modifier composition for the low carbon mesophilic asphalt mixture.

In order to achieve the above object, the present invention is 4 to 30 parts by weight of slaked lime and 4 to 30 parts by weight of waste tire powder is heated, melted and mixed with respect to 100 parts by weight of wax, the composition for low-carbon medium temperature asphalt mixture To provide.

In addition, the present invention in the production of asphalt mixture by mixing the aggregate and asphalt, low carbon medium temperature, characterized in that 94 ~ 96% by weight of the aggregate and filler, 4 ~ 6% by weight of the asphalt and the modifier is added and mixed in a plant mix method It provides a method of producing a type asphalt mixture.

 Hereinafter, the present invention will be described in detail.

The present invention provides a modifier composition for a low carbon mesophilic asphalt mixture, characterized in that 4 to 30 parts by weight of slaked lime and 4 to 30 parts by weight of waste tire powder are heated, melted and mixed with respect to 100 parts by weight of wax. The present invention is used in the medium temperature asphalt mixture (WMA) prepared by mixing asphalt, additives, aggregates, etc. to lower the mixing and compaction temperature of the heated asphalt mixture (HMA), the asphalt used in the medium temperature asphalt mixture It relates to a low carbon modifier composition added to.

In the modifier composition for the low carbon medium temperature asphalt mixture of the present invention, the weight ratio of the wax: slaked lime: waste tire powder is preferably 4: 1: 1.

In addition, in the modifier composition for a low carbon medium temperature asphalt mixture of the present invention, the wax contains polyethylene wax and vegetable wax in a weight ratio of 20: 1 to 1: 2, the vegetable wax, palm oil extracted from coconut (palm oil) of hydrogenated sodium hydroxide (NaOH) in a palm wax produced and stearic acid to the _{(CH 3 (CH 2) 16} COOH) the melt reaction of modified palm of 80 ℃ ~ 110 ℃ melting point generation wax are preferred, and In this case, the polyethylene wax has a melting point of 95 ° C. to 120 ° C., and a melt viscosity of 135 ° C. or less is 400 cPs or less, and the vegetable wax is obtained by hydrogenating palm oil extracted from a coconut to a modified palm wax. It is more preferable that the melting point of the palm wax having a melting point of 55 ° C ~ 65 ° C is further mixed, and further, the weight ratio of the hydrogenated palm wax and sodium hydroxide (NaOH) is within 100: 3.5 100: 4.0, and a weight ratio of the palm wax and the stearic acid is 100: more preferably from 27.5: 16.0 to 100.

The hydrated lime is obtained by calcining limestone (main component: CaCO ₃ ) by adding water to hydrated lime (CaO). The molecular formula is Ca (OH) ₂ . As can be seen from the molecular formula, limestone is heated to blow carbon dioxide gas.

The greatest advantage of the slaked lime component used in the present invention is that it exhibits resistance to the penetration of moisture that penetrates mesophilic asphalt concrete. This is due to the chemical structure of slaked lime and its mechanism is as follows. Slaked lime has a chemical structure of Ca (OH) ₂ , which is a mixture of CaO + H ₂ O. Here, the amount of water mixed with the calcium oxide is very small, and serves to promote the hydration reaction between the water and calcium oxide that penetrate the outside, and the hydration reaction of the mixture through the enhancement of the strength of the slaked lime dispersed in mesophilic asphalt concrete Improve the overall strength. In addition, calcined lime is evenly dispersed in the additives and asphalt of medium-temperature asphalt concrete as a filler. Thus, the hydration reaction of slaked lime and water forms a mechanism for improving strength and adhesion to asphalt.

Meanwhile, the waste tire powder is mainly composed of SBR (Styrene-Butadiene-Rubber), which is a synthetic rubber made by copolymerization of styrene and butadiene. Specifically, the polymer material is -CH ₂ CH (C ₆ H ₅ ) -CH ₂ -CH = CH-CH ₂ -and the like.

The waste tire rubber powder used in the present invention is a recycled component produced by pulverizing waste tires, and the chemical components and components of the waste tire rubber powder have been reported as follows. SBR blends, natural rubber, SBS, oil, carbon black, antioxidants, sunscreens, ozone blockers, etc. are expected to act as components to improve tire durability. Therefore, it is said that the waste tire rubber powder is mixed with the mesophilic type additive to use an integrated type, and it is believed that the problem of low temperature cracking due to the wax component of the mesophilic type additive is somewhat resolved.

After the middle temperature type additive containing waste tire rubber powder is put into ascon, the physical behavior is inferred as follows. Waste tire rubber powder is melted at a slightly higher temperature (180 ~ 200 ℃) than normal ascon production temperature (160 ~ 170 ℃), so the waste tire rubber powder is not completely melted under the production temperature of medium temperature ascon which is relatively lower than general ascon. Will not. Therefore, the surface of the rubber powder is melted by heat and adhered to the aggregate, and the inside of the rubber powder is considered to remain in a state capable of exerting elasticity (unmelted natural or slightly melted).

Therefore, due to the physical state of the waste tire rubber powder, aggregates of the middle temperature type asphalt concrete are attached to the outside of the molten waste tire rubber powder, and this adhesive force can exert a higher adhesive force together with the adhesive strength of the asphalt itself, and this improved performance Is expected to improve low temperature cracking resistance and other quality problems of mesophilic ascone.

The modifier composition of the present invention may be used as a wax for modifying the physical properties of asphalt, but any type of wax may be used, but polyethylene wax by Fischer Tropsch Synthesis method is basically used. When polyethylene wax is used, it is a typical polyolefin petroleum wax with a number average molecular weight of 800-1,200 and a melting point of 100-120 degreeC. The amount of polyethylene wax added acts as a compatibilizer to improve the compatibility of the modifier composition and at the same time serves to assist the function of the modifier composition. When the medium-temperature asphalt mixture (WMA) is manufactured using the polyethylene wax, the fluidity required for mixing the aggregate and the asphalt or compacting the medium-temperature asphalt mixture can reduce the working temperature of the asphalt and improve the high temperature properties. It becomes possible. In this case, the polyethylene wax according to the present invention has a melting point of 95 ° C. to 120 ° C., and a melt viscosity at 140 ° C. of 400 cPs (Centipoise) or less.

If the melting point of the polyethylene-based wax is lower than 95 ℃, the stiffness of the asphalt may be weakened when mixing with asphalt, and if the melting temperature is higher than 120 ℃ may not be a sufficient dissolution occurs in the middle temperature asphalt mixture manufacturing step may be a problem. If the melt viscosity at 135 ° C. is higher than 400 cPs, the viscosity of the asphalt is so high that the neutralization of the asphalt mixture cannot be achieved.

On the other hand, if only the polyethylene-based wax having a long linear structure (Long Chin Aliphatic Hydrocarbon) manufactured by the Fischer Rope shoe method to obtain the performance improvement by the mesophilic asphalt modifier composition as described above will be limited in wax selection In addition, low temperature cracking may result in low temperature properties. Therefore, it is desirable to add another material in order to remove the selection limitation of the polyethylene wax and to prevent the lowering of the low temperature properties while maintaining the high temperature characteristics. Therefore, the present invention adds vegetable wax as a constituent of the modifier crude.

That is, by using a low carbon additive containing a polyethylene-based wax and a vegetable wax to prepare a low carbon mesophilic type asphalt modifier composition to prevent low temperature properties.

At this time, the vegetable wax constituting the modifier composition is a polyethylene-based and vegetable wax to be contained in a weight ratio of 20: 1 to 1: 2, but preferably 5: 1 to 1: 2. For example, the vegetable wax is preferably 5 to 200 parts by weight, preferably 20 to 200 parts by weight based on 100 parts by weight of the polyethylene wax. The reason is that when the weight of the vegetable wax is less than 5 parts by weight, it is difficult to improve the low temperature properties of the medium temperature asphalt mixture (WMA), and when it exceeds 200 parts by weight, the high temperature properties of the medium temperature asphalt mixture (WMA) are deteriorated.

Since the vegetable wax is used for improving the low temperature properties of the medium-temperature asphalt mixture (WMA), the vegetable wax may be a vegetable wax generally used in the art, but the palm wax obtained from the vegetable palm oil extracted from the coconut is obtained through a hydrogenation process. It is preferable that it is a wax. The melting temperature of the palm wax obtained through the hydrogenation process is 55 ~ 65 ℃.

On the other hand, the palm wax has a low melting point may have a limited effect of improving physical properties when mixed with asphalt. Therefore, in order to increase the melting point of palm wax, it is preferable to use palm wax modified with sodium hydroxide (NaOH) and stearic acid (CH ₃ (CH ₂ ) ₁₆ COOH).

The method for reforming the palm wax will be described in more detail. First, palm wax is added to a reactor to which a stirrer is maintained at 200 ° C. to melt the palm wax. After melting the palm wax, sodium hydroxide (NaOH) is added to 3.5 to 4.0 parts by weight based on 100 parts by weight of palm wax and stirred for 30 minutes to cause a chemical reaction to generate a fatty acid (RCOOH). At this time, carbon number of the produced | generated fatty acid is 12-16.

The produced fatty acid undergoes a second chemical reaction with sodium hydroxide to form a sodium salt having a high melting point. Similarly, the sodium salt produced is 12 to 16 carbon atoms.

In order to further increase the melting point of the modified palm wax, 16.0 to 27.5 parts by weight of stearic acid is added to 100 parts by weight of palm wax, and then stirred for about 2 hours, so that stearic acid reacts with sodium hydroxide to produce sodium stearic acid.

As a result of the modification, a modified palm wax having a melting point of 80 to 110 ° C. in which sodium salt and unreacted palm wax are mixed is finally produced. When preparing the modifier composition, the palm wax and the modified palm wax may be used alone or in combination.

On the other hand, it is preferable to further add oil to the modifier composition in order to further lower the viscosity of the asphalt mixture to facilitate neutralization.

The oils to be added are paraffinic and naphtanic oils having a kinematic viscosity at 40 ° C. of 20 to 300 cSt, and preferably 5 to 50 parts by weight based on 100 parts by weight of polyethylene wax. If the oil content exceeds 50 parts by weight, the viscosity of the modifier composition is lowered, but the high temperature physical properties of the composition are worse, and if the oil content is less than 5 parts by weight, the effect of reducing the viscosity of the composition is not large.

In addition, the present invention in the production of asphalt mixture by mixing the aggregate and asphalt, low carbon medium temperature, characterized in that 94 ~ 96% by weight of the aggregate and filler, 4 ~ 6% by weight of the asphalt and the modifier is added and mixed in a plant mix method It provides a method of producing a type asphalt mixture.

In the method for producing a low carbon mesophilic asphalt mixture of the present invention, the composition ratio of the asphalt: modifier is preferably 97 to 98: 2 to 3, wherein the composition ratio of the asphalt to the modifier is 97: 3 to PG 70-22. It is more preferable to meet the grade or to meet the PG 64-22 common grade with a composition ratio of asphalt: modifier of 98: 2.

The method for producing a low carbon mesophilic asphalt mixture (modified WMA) according to the present invention, when preparing an asphalt mixture (ascon) by combining aggregate and asphalt, the modifier for the low carbon mesophilic asphalt mixture of the present invention with respect to 100 parts by weight of the asphalt If the addition amount of the composition (WMA modifier) was less than 2% by weight based on 100 parts by weight of the asphalt mixture, the original | G * | / sinδ value of the modified asphalt at 64 ° C. was lower than 1.0 kPa, and after RTFO treatment | The G * | / sinδ value is lower than 2.2 kPa, so that the high temperature grade of PG 64 cannot be obtained, and the m-Value value is lower than 0.300 at minus 12 ° C (PG-22), so that Can not be obtained. In addition, when the addition amount of the WMA modifier was 3% by weight based on 100 parts by weight of the asphalt mixture, the original | G * | / sinδ value of the modified asphalt at 72 ° C. was higher than 1.0 kPa, and | G after RTFO treatment. The value of * | / sinδ is higher than 2.2 kPa to obtain a high temperature grade of PG 72. However, if the addition amount of the WMA modifier exceeds 3% by weight relative to 100 parts by weight of the asphalt mixture, there is no further increase in the PG grade, which is undesirable in terms of economy.

Figure 1 of the present invention is a graph showing the results of measuring the compaction energy trend of the asphalt mixture prepared in Examples 2, 3 and Comparative Examples 1 to 3 of the present invention, the compaction count for each sample based on the porosity of 8% It is a result of a measurement. If the porosity reaches 8% at low compaction counts, the sample has good fluidity. That is, the asphalt mixture prepared in Example 3 of the present invention showed the best fluidity, followed by Example 2, and the comparative examples were very lagging. The main reason for the good fluidity of this embodiment is due to the influence of the mesophilic additives introduced into the sample. As a result, the asphalt and dissolved mesophilic additives are evenly dispersed in the mixture pores at the middle temperature to increase the fluidity of the mixture, thereby increasing the relatively high compaction energy. It is shown.

As described above, the low carbon mesophilic asphalt mixture prepared by the present invention can reduce fuel consumption while minimizing the emission of harmful substances such as carbon dioxide during road construction, and the optimum mixing temperature and the optimum compaction temperature are about 15- It can lower the temperature by 25 ℃, and the common grade that shows high temperature plastic change resistance and low temperature cracking resistance expresses 64-22 to PG 70-22, and is suitable for the construction of the walkway that takes a long time for transportation and paving waiting time of WMA, It shows sufficient compaction.

1 is a graph showing the results of measuring the compaction energy trend of the asphalt mixture prepared in Examples and Comparative Examples of the present invention.

Hereinafter, the present invention will be described in more detail based on the following examples. It should be noted, however, that the following examples are for illustrative purposes only and are not intended to limit the scope of the present invention. The present invention is not limited to the following examples. Will be apparent to those skilled in the art to which the present invention pertains.

Example 1 Preparation of Modifier Composition for Low Carbon Medium Temperature Asphalt Mixtures

Sodium hydroxide was added to a palm wax prepared by adding 300 g of polyethylene wax having a melting point of 95 ° C. to 120 ° C. and a melt viscosity of 400 cPs at 135 ° C., and palm oil extracted from coconut. 50 g of modified palm wax having a melting point of 80 ° C. to 110 ° C., 50 g of palm wax having a melting point of 55 ° C. to 65 ° C., and 100 g of calcined lime produced by melting and reacting (NaOH) and stearic acid (CH ₃ (CH ₂ ) ₁₆ COOH). After adding 100 g of waste tire, setting the stirrer and thermometer, and adjusting the temperature of the automatic temperature coat roller to 160 ° C. through the mantle heater, when the temperature of the contents reaches 150 ° C., the temperature is raised to 160 ° C. while stirring. 1 hour at the same temperature. After the contents were homogeneous, the contents were extracted in a spherical shape of about Φ 5 mm through a simple spherical device. The modifier composition prepared by the above procedure yielded a WMA modifier composition having a softening point of about 118 ° C. The melt mixed modifier composition was cooled by dropping it into 3 L of cooling water.

Example 2 Preparation of Low Carbon Medium Temperature Asphalt Mixture 1

Aggregate and filler 94.2 g were mixed to mix 5.63 g of asphalt, and 0.17 g of the modifier composition prepared in Example was added and mixed in a plant mix to prepare a mesophilic asphalt mixture of the present invention.

Example 3 Preparation of Low Carbon Medium Temperature Asphalt Mixture 2

Aggregate and filler 94.2 g were mixed to mix 5.68 g of asphalt and 0.12 g of the modifier composition prepared in the above example was added and mixed in a plant mix to prepare a mesophilic asphalt mixture of the present invention.

≪ Comparative Example 1 &

Preparation or construction of asphalt mixture and melt viscosity measurement sample (asphalt modifier), respectively, in the same manner as in Example 2 except for adding 5.8 g of asphalt without adding the modifier composition of the present invention at the time of preparing the low-carbon medium temperature asphalt mixture. It was.

Comparative Example 2

Asphalt mixture and melt viscosity measurement sample (asphalt modifier) were prepared in the same manner as in Example 2, except that 0.17 g of Sassobit Wax was added instead of the modifier composition of the present invention when preparing the low-carbon, medium-temperature asphalt mixture. It was.

≪ Comparative Example 3 &

Instead of the modifier composition of the present invention, the asphalt mixture and the melt viscosity measurement sample were prepared in the same manner as in Example 2, except that 0.02 g of sasobit wax and 0.15 g of polyethylene resin pellets were homogeneously mixed. Prepared.

<Test Example>

The results obtained by evaluating the optimum mixing temperature and the optimum compaction temperature of the medium-temperature asphalt mixture (WMA) or WMA prepared in Examples 2 and 3 and Comparative Examples 1 to 3, respectively, are described in Table 1 and FIG. Same as 1.

division Optimal Mixing Temperature (℃) [Specification: 150 ~ 300cps Temperature] Optimum Compaction Temperature (℃) [Specification: 150 ~ 300cps Temperature] WMA Efficiency Example 2 125-135 115-125 Great Example 3 120-130 110-120 Great Comparative Example 1 150-165 140-150 Bad Comparative Example 2 140-155 135-140 usually Comparative Example 3 160-175 150 ~ 160 Bad

As shown in Table 1, the medium-temperature asphalt mixture (WMA) prepared in Examples 2 to 3 has an optimum mixing temperature and an optimum compaction temperature of about 30 ° C. lower than that of Comparative Example 1, and 15 than the WMA of Comparative Example 2. 20 ° C. is lower and 40 ° C. lower than the WMA of Comparative Example 3, thereby reducing energy consumption and harmful emissions during road construction.

As shown in Table 1, the optimum mixing temperature and the optimum compaction temperature are obtained by measuring the melt viscosity of each sample of the viscosity measurement sample (asphalt modifier) prepared in Examples 2, 3, and Comparative Examples 1 to 3. After the measurement, a graph showing the change in melt viscosity according to the temperature change was made. Based on the WMA formulation design guideline of the Ministry of Land, Transport and Maritime Affairs in 2005, the temperature of WMA melt viscosity of 150-300 CPS was evaluated as the optimum mixing temperature. The melt viscosity of WMA of 300-400 CPS was evaluated as the optimum compaction temperature.

In addition, Figure 1 is a graph showing the results of measuring the compaction energy trend of the asphalt mixture prepared in the above Examples and Comparative Examples. Considering that the porosity of the asphalt mixture was compacted by the compaction roller at the pavement site, the compaction frequency of each mixture was analyzed based on the 8% porosity of the longitudinal axis. In conclusion, the smaller the number of compaction, the better the fluidity of the asphalt mixture means that the target porosity of 8% is reached in a short time. The higher the number of compaction, the longer the time to reach the target porosity.

The main cause of this tendency is due to the characteristics of the mesophilic modifiers added to the Examples and Comparative Examples, and it is analyzed that the composition prepared in the Example exhibits relatively higher workability and fluidity than the composition of the Comparative Example. This can reduce the construction time in the field, there is an advantage that can be opened quickly after the completion of construction.

Meanwhile, after evaluating each of the high temperature plastic change resistance and the low temperature crack resistance of each of WMA or WMA prepared in Examples 2, 3, and Comparative Examples 1 to 3, the modified WMA reflecting these physical properties was evaluated. Or, the evaluation results of WMA Performance Grade (PG) common grade are as follows.

Various physical properties were collected in Examples 2, 3, and Comparative Examples 1 to 3, respectively, and 35 0.5 0.5 g of the melt viscosity measurement sample (asphalt modifier) was collected at 163 ° C by the test method of KS M 2259 standard. 85 minutes RTFO (Rolling Thin Film Oven, thin film heating test: Simulates the aging process of mixing with aggregate and moving to the site at high temperature in the initial plant during the production of asphalt mixture) It was.

In addition, each raw material before the RTFO treatment was prepared by using a BBR (Bending Beam Rheometer) mold in accordance with the test method of the KS F 2390 standard BBR test piece.

With each original sample and RTFO-treated sample, DSR test, which is a high temperature grade test of PG, was carried out according to KS F 2393 standard, and the value of | G * | / sinδ (factor related to plastic deformation resistance of asphalt) was measured. The temperature at which the | G * | / sinδ value is 1.0 kPa or more and the | G * | / sinδ value of the RTFO treated sample simultaneously satisfies a value of 2.2 kPa or more is determined as a PG high temperature grade indicating high temperature plastic change resistance.

In addition, low-temperature crack resistance evaluation was carried out in accordance with the KS F 2390 standard with each BBR sample prepared in advance, the creep stiffness (asphalt stiffness at low temperature due to bending creep stiffness, 300 MPa or less) is 300 MPa or less and the slope The temperature at which the m-Value (with or without brittle fracture of 0.3 or more due to bending creep slope) was 0.300 or more was determined as a PG low temperature grade having low temperature crack resistance.

In conclusion, the WMA modifier of the present invention can lower the optimum mixing temperature and the compaction temperature, which are the objectives of the present invention, by about 25 to 35 ° C. below the optimum mixing temperature and the optimum compaction temperature of the conventional HMA and Sasobit Wax alone. PG 70-22 (Example 2), PG 64-22 (Example 3) can be seen that the common grade showing the high temperature plastic change resistance and low temperature crack resistance while exhibiting excellent WMA function.

Therefore, the WMA modifier of the present invention can lower the mixing temperature and compaction temperature by about 30 ~ 35 ℃ than the conventional HMA EES.inc. Green Way can reduce emissions of hazardous emissions, CO ₂ emissions and fuel consumption by about 11-35%, such as the report and TRB's "Energy and environmental gains of warm & half-warm asphalt mix: Quantitative approach" report. At the same time, it is possible to express sufficient compaction even in pavement such as a bicycle-only road, a river bank park road and a promenade, where the asphalt mixture has a long transport distance and long pavement waiting time.

The WMA pavement method using the WMA modifier of the present invention has the advantage that the concrete pavement method can be transported within 1 to 2 hours, while the curing time requires several weeks of curing, the elasticity of the package is superior to the concrete, and the packaging cost is also economical For this reason, it is useful as a packaging material for sub-contractors.

On the other hand, the results of evaluating the melt viscosity and solubility index (INDEX) of the modified WMA prepared in Example 2 and Comparative Example 3 are shown in Table 2 below.

division Example 2 Comparative Example 3 Store at 120 ℃ for 20 minutes 120 ℃ 40 minutes storage 120 ℃ 60 minutes storage Store at 120 ℃ for 20 minutes 120 ℃ 40 minutes storage 120 ℃ 60 minutes storage Solubility Index One One One 9 9 7 Melting degree (ps) 230 240 240 450 490 512

Solubility index 1 means complete dissolution and 9 indicates complete insolubility. In other words, the solubility index decreases from 1 to 9 solubility.

Example 2 is excellent in solubility at 125 ℃ but Comparative Example 3 was found that the low-density polyethylene in the WMA hardly dissolved at 125 ℃.

On the other hand, the Marshall stability of the modified WMA prepared in Examples 2, 3, Comparative Example 1 and Comparative Example 3 of the present invention was measured by the KS F 2349 method, and the dynamic stability was measured by the KS F 2374 method. The results were shown in Table 3.

division Marshall Stability (Related Standard: 5000 kgf or more) Dynamic Stability (3,000 times / mm) Example 2 2,750 6,230 Example 3 2,600 5,780 Comparative Example 1 1,020 3,110 Comparative Example 3 1,450 3,890

As such, the reason why the embodiment of the present invention exhibits superior physical properties than that of the comparative example is due to the characteristics of slaked lime and waste tire powder added to the modifier composition.

It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are intended to provide further explanation of the invention, and are not intended to limit the scope of the invention. .

Claims (10)

4 to 30 parts by weight of hydrated lime and 4 to 30 parts by weight of waste tire powder are heated, melted and mixed with respect to 100 parts by weight of wax, wherein the wax is a weight ratio of 5: 1 to 1: 2 of polyethylene wax and vegetable wax. The polyethylene wax has a melting point of 95 ° C. to 120 ° C., a melt viscosity of less than 400 cPs at 135 ° C., and the vegetable wax has a melting point of 80 ° C. to 110 ° C. Modifier composition for the asphalt mixture.
delete The method of claim 1, wherein the vegetable wax, the sodium wax (NaOH) and stearic acid (CH ₃ (CH ₂ ) ₁₆ COOH) by melting the palm wax extracted from palm oil (Palm oil) by melting the reaction Modified composition for a low carbon mesophilic asphalt mixture, characterized in that the produced palm wax of the melting point 80 ℃ ~ 110 ℃.
delete The method of claim 3, wherein the vegetable wax is produced by mixing the palm wax having a melting point of 55 ℃ ~ 65 ℃ to the modified palm wax, hydrogenated by palm oil (Palm oil) extracted from the coconut Modifier composition for low carbon medium temperature asphalt mixture.
delete In preparing the asphalt mixture by combining the aggregate with the asphalt and the modifier composition, the modifier composition uses the modifier composition selected from claim 1, 3 or 5, and the weight ratio of the asphalt to the modifier composition is 97: 3. Low carbon mesophilic asphalt mixture, characterized by meeting the 70-22 common grade.
In preparing an asphalt mixture by combining the aggregate with the asphalt and the modifier composition, the modifier composition uses a modifier composition selected from Claims 1, 3 or 5, and the weight ratio of the asphalt: modifier composition is 98: 2. Low carbon mesophilic asphalt mixture, characterized in that it meets the 64-22 common grade. delete delete

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