KR100949381B1 - Asphalt for low carbon dioxide green growth of warm-mix asphalt and worm-mix asphalt mixture making method therewith - Google Patents

Abstract

PURPOSE: Warm-mix asphalt is provided to be applied to plant mix and premix type by adding low carbon dioxide additives to asphalt, to reduce heating energy required for preparing warm-mix asphalt and the generation of carbon dioxide. CONSTITUTION: Warm-mix asphalt is prepared by mixing asphalt and low carbon dioxide additive in a weight ratio of 100:0.5 - 100:15. The low carbon dioxide additive comprises polyethylene-based wax and vegetable wax in a weight ratio of 20:1 - 1:2. The vegetable wax is modified palm wax. The modified palm wax is prepared by performing hydrogenation of palm oil extracted from palm nuts to make palm wax, and then fusing NaOH and stearic acid in the palm wax.

Description

Medium temperature asphalt prepared with low carbon additive and medium temperature asphalt mixture manufacturing method using the same {ASPHALT FOR LOW CARBON DIOXIDE GREEN GROWTH OF WARM-MIX ASPHALT AND WORM-MIX ASPHALT MIXTURE MAKING METHOD THEREWITH}

The present invention relates to a medium temperature asphalt prepared with a low carbon additive and a method for producing a medium temperature asphalt mixture using the same. The present invention improves the resistance to high temperature plastic deformation while lowering the mixing and compacting temperature of the medium-temperature asphalt mixture by using a polyethylene wax and a vegetable wax, and a low carbon additive capable of suppressing the low temperature property degradation caused by using a polyethylene wax. It relates to a medium warmed asphalt used and a method for producing a medium temperature asphalt mixture using the same.

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 at the European Climate Exchange in Amsterdam, the world's largest market in 2006, and more than 50% of carbon credit trading volume is increasing each year, increasing interest in carbon credits. have.

Asphalt concrete (asphalt mixture, asphalt concrete) pavement technology has been actively studied to reduce carbon dioxide emission in accordance with this atmosphere.

Among them, the most attention in terms of practicality and scale is the field of road pavement technology using a low carbon asphalt mixture that can lower the mixing and compaction temperature of asphalt concrete (asphalt mixture, asphalt concrete).

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.

Asphalt is mainly used for paving roads, and petroleum-based asphalt is mainly petroleum-based asphalt. (Straight Asphalt is mainly used. Such straight asphalt is commonly referred to as an asphalt binder.) 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 in order to manufacture the asphalt mixture, there is a problem that the emissions of harmful gases such as carbon dioxide (CO ₂ ) increases 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.

That is, 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.

The road pavement technology using the medium temperature asphalt mixture (WMA) is compared to the conventional road pavement technology by the heated asphalt mixture (HMA).

Since the asphalt mixture can be produced at a temperature of about 110 to 150 ° C., which is 30 to 40 ° C. lower than the temperature required to prepare the asphalt mixture,

(1) It can suppress the generation of various harmful gases in the production and construction of asphalt mixtures,

(2) It can reduce about 30% of petroleum fuel, which is the main culprit of greenhouse gas, in the production of asphalt mixtures,

(3) Fast opening of traffic is possible by shortening curing time after construction of asphalt mixture,

(4) It has many advantages, such as ensuring no worker's safety because no harmful vapor or odor occurs at construction site.

Core Mechanism of this medium asphalt mixture (WMA) paving technology is expressed at lower temperatures such that the optimum viscosity of asphalt, which is the binder of the aggregate, is improved than that of the heated asphalt mixture (HMA), and also the optimum compaction ( It is a technology to lower the viscosity so that it can be expressed at a low temperature so as to have a compaction rate.

This viscosity-lowering technology was first introduced in 1956 by Dr. Ladis H.Csanyl of the University of Iowa, USA, by injecting steam into the asphalt, forming foamed asphalt with moisture and air in the asphalt, thereby lowering the viscosity of 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. It has been developed to produce a foam-medium asphalt mixture (Foam-WMA) that emulsifies asphalt as the water moistened in the asphalt is discharged.

Meanwhile, since 2005, a medium temperature asphalt mixture (WMA) using waxes, ie, Sasobit wax manufactured by Fischer Tropsch Synthesis, has been reported by 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) obtaining polyethylene wax from low molecular weight by-products from the process of making polyethylene resin, or

(2) producing a polyethylene wax by thermal decomposition of the polyethylene resin to reduce the molecular weight;

(3) Prepared by 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.

That is, the greater the linearity of the main chain of polyethylene wax, the higher the molecular regularity, the higher the crystallinity and the higher the physical properties such as melting point and hardness. The higher the molecular weight of the polyethylene wax, the higher the viscosity and physical properties of the polyethylene wax. It is known that it can be manufactured.

As a result, polyethylene waxes obtained by thermal decomposition of by-products or polyethylene resins in the process of making polyethylene resins have a lower linearity compared to polyethylene waxes produced by the Fischer Ropsch process and have a higher melt viscosity 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 alkane structure, so compared to 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.

Therefore, Sasobit wax prepared by Fischer Tropsch Synthesis process has been used as a very effective low carbon additive in mesophilic asphalt mixtures.

Polyethylene waxes such as Sasobit wax, however, have very high temperature characteristics such as resistance to plastic deformation (Permanent Deformation), while the stiffness increases and the stiffness changes in asphalt after prolonged aging. As the m-value decreases, the low-temperature physical properties of the asphalt decrease as the elasticity of the asphalt decreases.

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.

After all, the problem of low-carbon additives will have a direct impact on the asphalt and asphalt mixtures using the same, so the problems of using polyethylene waxes in the case of asphalt using conventional polyethylene waxes and mesophilic asphalt mixtures using the same I had to have. Therefore, there is a need to improve this.

The present invention is to solve the above problems, the present invention by adding a low-carbon additive containing the polyethylene-based wax and vegetable wax to the asphalt, as well as the plant mix as well as the medium temperature asphalt and the medium temperature asphalt using the same Suggest a mixture.

In addition, the present invention is a low-carbon additive added to mesophilic asphalt, as well as lowering the low-temperature physical properties of the mesophilic asphalt mixture using polyethylene wax prepared by Fischer Ropsch method, such as Sasobit wax, as well as polyethylene wax prepared by other methods. We propose a new low carbon additive for medium temperature asphalt mixture that can prevent the phenomenon.

Thus, it is possible to effectively lower the mixing and compaction temperature of the medium-temperature asphalt mixture (WMA) to reduce the heating energy required when paving the road using the asphalt mixture to reduce the carbon dioxide emissions and thereby lay the foundation for green growth do.

In order to achieve the above technical problem, first, a low carbon additive for a medium temperature asphalt mixture prepared to reduce carbon dioxide emissions is proposed, and the low carbon additive is mixed with a predetermined weight part of vegetable wax in polyethylene wax added to the medium temperature asphalt mixture (WMA). To manufacture.

In addition, the present invention is to mix the low carbon additive and asphalt, but present the weight ratio to be mixed, and the prepared warming asphalt is mixed with the final aggregate, etc. to be able to produce a medium-temperature asphalt mixture.

Preferably, the moderate temperature asphalt according to the present invention is prepared by mixing the asphalt and the low carbon additive in a weight part of 100: 0.5 to 100: 15,

The low carbon additive may be prepared by containing the polyethylene wax and the vegetable wax in a weight ratio of 20: 1 to 1: 2.

Also preferably, the low carbon additive for the intermediate temperature asphalt mixture is configured to contain polyethylene wax and vegetable wax in a weight ratio of 20: 1 to 1: 2, and the low carbon additive further contains an oil, and the polyethylene wax And the weight ratio of the oil was 20: 1 to 2: 1.

Further, preferably, the polyethylene wax has a melting point of 95 ° C to 125 ° C and a melting point of 140 ° C of 400 cPs (Centipoise) or less.

Preferably, the vegetable wax is a palm wax prepared from palm oil extracted from coconut or a modified palm wax obtained by melting the palm wax with sodium hydroxide (NaOH) and stearic acid (CH ₃ (CH ₂ ) ₁₆ COOH). At least one of

Preferably, in the case of the modified palm wax, the weight ratio of the palm wax and the sodium hydroxide (NaOH) is 100: 3.5 to 100: 4.0, the weight ratio of the palm wax and the stearic acid is 100: 16.0 to 100: 27.5.

In addition, preferably the palm wax has a melting point of 55 ℃ to 65 ℃, the modified palm wax has a melting point of 80 ℃ to 110 ℃.

Also preferably, the oil has a Kinematic Viscosity of 40 ° C. of 20 to 300 cSt (centistokes, mm 2 / s).

According to the present invention, when the neutralized asphalt is manufactured by using a low carbon additive including polyethylene wax and vegetable wax, the melting time is not long, and thus the neutralized asphalt can be produced in the premix type as well as the plant mix type in a short time. The heating energy required for the manufacture of asphalt mixtures can be reduced, significantly reducing the amount of carbon dioxide that is the main culprit of global warming.

Furthermore, the asphalt concrete pavement work can be performed while suppressing the generation of various harmful gases generated during the construction by mixing and compacting the asphalt mixture.

In addition, even in the low carbon additive, it is possible to manufacture an effective medium-temperature asphalt mixture (WMA) using not only the polyethylene wax manufactured by the Fischer Trough shoe method but also the polyethylene wax manufactured by other methods, and by adding the vegetable wax in the production of the polyethylene wax Due to this, it is possible to prevent the low temperature property degradation, which is a problem of the medium temperature asphalt mixture (WMA) using polyethylene wax.

In addition, since the medium temperature ascon can be produced as a plant mix type, it can be applied to all asphalt mixture plants regardless of the facility characteristics of domestic ascon plants.

In addition, it is possible to carry out asphalt mixture paving work while reducing heating energy while operating the asphalt mixture plant and restraining the generation of various harmful gases and ensuring worker safety. Can be. In addition, pavement work can be easily performed even in short sections that are difficult to apply the premix type or sections that are not easily accessible.

EMBODIMENT OF THE INVENTION Hereinafter, this invention is demonstrated in detail.

The present invention relates to a mesophilic asphalt prepared by adding a low carbon additive for mesophilic asphalt mixture including polyethylene-based wax and a vegetable wax to the asphalt and a mesophilic asphalt mixture (WMA) using the same.

First, the low carbon additive for mesophilic asphalt mixture to be mixed with the asphalt of the present invention will be described.

The low carbon additive added to the asphalt in the present invention is to be used in the medium temperature asphalt mixture (WMA) prepared by mixing the asphalt, additives, aggregates, etc. to lower the mixing and compaction temperature of the heated asphalt mixture (HMA).

In this case, the low carbon additive is used to modify physical properties of asphalt, and a polyethylene wax by Fischer Tropsch Synthesis is basically used.

 The production of medium temperature asphalt mixture (WMA) using such polyethylene wax can ensure the required fluidity when mixing aggregate and asphalt or compaction of medium temperature asphalt mixture, which can lower the working temperature of asphalt and improve the high temperature properties. Will be.

In this case, the polyethylene wax according to the present invention has a melting point of 95 ° C to 125 ° C and a melt viscosity of 140 ° C or less of 400 cPs (Centipoise).

If the melting point of the polyethylene wax is lower than 95 ℃, the stiffness of the asphalt may be weakened when mixed with asphalt, and if the melting temperature is higher than 125 ℃ may not be a sufficient dissolution in the intermediate temperature mixture manufacturing step may be a problem. When the melt viscosity at 140 ° 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 medium temperature asphalt mixture as described above, not only limited to the wax selection Low temperature cracks result in lowered physical properties.

Therefore, it is necessary to add another material in order to remove the limitation of the polyethylene-based wax and to prevent the low temperature properties while maintaining the high temperature characteristics.

Accordingly, the present invention adds a vegetable wax as a constituent of the additive for a moderate temperature asphalt mixture.

In other words, by using a low carbon additive containing a polyethylene wax and a vegetable wax to prepare a medium-temperature asphalt mixture (asphalt concrete) to prevent the lowering of physical properties.

At this time, the vegetable wax constituting the additive for the medium-temperature asphalt mixture is such that the polyethylene-based and vegetable wax is 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 3.5 ~ 4.0 parts by weight based on 100 parts by weight of palm wax and stirred for 30 minutes to produce a fatty acid (RCOOH) by the following chemical reaction.

Here, R1, R2 and R3 are alkyl groups having 12 to 16 carbons.

The produced fatty acid is subjected to a secondary chemical reaction with sodium hydroxide to form a sodium salt having a high melting point.

Here, R1, R2 and R3 are alkyl groups having 12 to 16 carbons.

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. Thus, stearic acid reacts with sodium hydroxide to produce sodium stearic acid.

Where R4 is stearin.

As a result of the modification, a modified palm wax at a melting point of 80 to 110 ° C. in which sodium salt and unreacted palm wax were mixed as follows is finally produced.

Here, R1, R2 and R3 are alkyl groups having 12 to 16 carbons, and R4 is stearin.

When producing the low carbon additive, 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 low carbon additive in order to further lower the viscosity of the asphalt mixture to achieve mesothermalization.

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 is more than 50 parts by weight, the viscosity of the asphalt mixture is lowered, but the high temperature properties of the asphalt mixture are worse, and if the oil content is less than 5 parts by weight, the effect of reducing the viscosity of the asphalt mixture is not great.

Next, the low-carbon additives discussed above are manufactured to mix with asphalt.

That is, the low carbon additive according to the present invention may be used to produce medium temperature ascon in a plant mix type (Plant-mix-type) by mixing in an asphalt mixing plant with asphalt and aggregate at 110-150 ° C.

In addition, after melting and mixing the low-carbon additives with asphalt, the melt mixture is added to the asphalt mixing plant together with the aggregate to produce a medium temperature ascon in the pre-mix-type of mixing at 110 ~ 150 ℃. It may be.

In order to produce a medium-temperature asphalt mixture, 3.5 to 8.0 parts by weight of asphalt and 92.0 to 96.5 parts of aggregate are to be prepared, but mixing the low carbon additive of the present invention with asphalt and the low carbon additive to 100 parts by weight of 100: 0.5 to 100: 15 desirable.

This is because when the low carbon additive is used in an amount of 15 parts by weight or more, the cantabro loss rate for evaluating the aggregate desorption and durability at room temperature is not good, and when it is used less than 0.5 parts by weight, there is almost no neutralization effect.

In addition, the asphalt mixed with the low carbon additive of the present invention may be any asphalt used for road pavement, but considering the use of asphalt having an invasion grade of 80 to 100 and an invasive grade of 60 to 80 as road paving asphalt. It would be desirable to use asphalt of this grade.

Hereinafter, the present invention will be described in more detail based on experimental examples. However, the following experiments are merely illustrative of the present invention, and the scope of the present invention is not limited to the following experimental examples.

Experimental Example

(1) Experimental material

AP: Asphalt with 60 Penetration Grade 60 to 80 Penetration

PE-M: polyethylene wax with melting point 114 ℃, 140 ℃ viscosity 200cps and specific gravity 0.93

PE-H: polyethylene wax with melting point 115 ℃, 140 ℃ viscosity 800cps and specific gravity 0.93

Sasobit: Polyethylene wax from Sasol with melting point 112 ℃ and 140 ℃ viscosity 40cps (trade name sasobit)

Palm: Palm wax extracted from coconut with melting point of 60 ℃ and viscosity of 6 ℃

M-palm: A modified palm wax having a melting point of 100 ° C. and a viscosity of 15 cps at 140 ° C. obtained by reacting with palm wax 76.2%, sodium hydroxide 3.8% and stearic acid 20.0%.

Oil: Paraffinic oil with 40 ℃ kinematic viscosity of 100 cSt

(2) Preparation of Low Carbon Additives for Medium Temperature Asphalt Mixtures

The low carbon additive was prepared by adding about 300 g of polyethylene wax, palm wax, oil, etc. to a 1L reactor, heating and melting at 180 ° C., followed by melt mixing for 20 minutes with a stirrer. The melt-mixed additive was dropped into 3 L of cooling water and cooled to obtain an additive having a size of about 1 to 2 mm.

The composition ratios of the examples and comparative examples low carbon additive thus prepared are shown in [Table 1] and [Table 2]. The following tables are shown based on PHR (PER HUNDRED RESIN).

Unit (phr) Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 PE-M 100 100 100 100 100 100 Palm 20 60 200 60 30 5 M-palm - - - - 30 - oil - - - 30 - -

Unit (phr) Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 Comparative Example 6 PE-M 100 100 - - - - PE-H - - 100 100 100 - Sasobit - - - - - 100 Palm - 250 - 250 60 - M-palm - - - - - - oil - - - - 70 -

Looking at the characteristics of Comparative Examples 1 to 6 prepared as described above are as shown in Table 3 below.

division unit Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 Comparative Example 6 Softening point ℃ 120 60 132 66 65 123 Viscosity (140 ℃) cPs 140 32 210 48 52 55 Trespassing 0.1mm 0.1 20.0 0.1 15.0 17.3 0.1 density g / cm 3 0.93 0.93 0.94 0.94 0.94 0.94

(3) Manufacture of moderately warmed asphalt (asphalt mixed with low carbon additive of the present invention)

3 parts by weight of an additive for a moderate temperature asphalt mixture was added to 100 parts by weight of the AP (asphalt) heated to 130 ° C., followed by stirring for 20 minutes using a high speed shear mixer at 2,000 rpm to completely melt the additive.

(4) Evaluation of mesophilic asphalt properties

Evaluation of the physical properties of each asphalt (AP), including the neutralized asphalt prepared by adding the additive according to the present invention was evaluated based on the PG test, the viscosity was measured by measuring a rotary viscometer. Physical properties of the neutralized asphalt of each Example and Comparative Example are shown in Table 4. Here, the content of the low carbon additive used is 3 parts by weight based on 100 parts by weight of the AP (asphalt).

 Low carbon additive Asphalt before aging Asphalt After RFTO Asphalt After PAV Viscosity (120 ℃, cps) Viscosity (140 ° C, cps) G ^* / sinδ (70 ° C, kPa) G ^* / sinδ (70 ° C, kPa) Stiffness (-12 ℃, MPa) m-value (-12 ℃) AP 1150 412 0.624 1.201 189 0.33 Example 1 950 330 3.254 4.112 200 0.32 Example 2 900 310 3.013 3.805 180 0.33 Example 3 790 290 1.251 2.101 166 0.35 Example 4 810 300 1.651 2.631 163 0.35 Example 5 910 315 3.282 4.382 195 0.33 Example 6 925 320 3.501 4.212 196 0.33 Comparative Example 1 1,067 385 4.276 4.423 245 0.28 Comparative Example 2 720 265 0.341 0.651 120 0.37 Comparative Example 3 1,250 450 4.783 5.023 275 0.27 Comparative Example 4 980 320 0.362 0.721 150 0.36 Comparative Example 5 730 290 0.461 0.891 140 0.37 Comparative Example 6 880 316 3.792 5.299 250 0.28 RTFO (Rolling Thin Film Oven): Simulates the aging of the process of mixing with aggregate and moving to the site at high temperature in the initial plant during the production of asphalt mixture PAV (Pressure Aging Vessel) Evaluation of Aging of Asphalt Mixtures Over (Use of 3 parts by weight of low-carbon additives in Examples and Comparative Examples) G ^* / sin δ: Factors related to plastic deformation resistance of asphalt Stiffness: Asphalt stiffness at low temperatures due to flexural creep stiffness (300 MPa) M-value: Whether the brittle fracture is abrupt due to bending creep slope (0.3 or more)

As shown in Table 4, it can be seen that the low carbon additive according to the present invention exhibits excellent overall high and low temperature physical properties.

If the viscosity is 120 ~ 140 ℃ higher than AP or G * / sinδ is lower in Original and RTFO, it is difficult to be used as low carbon additive because of low plastic deformation resistance.

In addition, when the m-value value after the PAV is more than 0.3 or higher than the AP, it can be determined that the low temperature properties are excellent.

In Comparative Examples 1 and 3 using general polyethylene wax, G * / sinδ was higher in Original and RTFO, but the viscosity was similar to or higher than PG 64-22 (KS F 2389; based on the common grade of asphalt). It is found to be unsuitable for use.

In addition, in this case, the m-value after PAV is less than 0.3 and lower than PG 64-22, so that the low temperature property is not good, and thus it is vulnerable to fatigue and cracking, which may limit its use in low temperature areas.

The sasobit wax of Comparative Example 6, which is used as a low carbon additive, has a low viscosity and excellent plastic deformation resistance, so it can be used as an excellent low carbon additive in a hot area. So it can be seen that the physical properties are not good.

On the other hand, the low carbon additives of Examples 1 to 6 according to the present invention can be used as a low carbon additive because the viscosity is 120 ~ 140 ℃ lower than PG 64-22, G * / sinδ is higher than PG 64-22 in Original and RTFO It can be seen that it has excellent plastic deformation resistance.

In addition, since after the PAV m-value value is 0.3 or more, it can be seen that it has a good high temperature plastic deformation resistance and excellent low temperature properties.

In addition, Comparative Examples 2 and 4 using excess palm wax may be used as low carbon additives due to their low viscosity. However, G * / sinδ values in Original and RTFO are lower than AP, making it difficult to use as asphalt additive for road pavement. It can be seen.

By using Example 2 by measuring the asphalt physical properties of the low carbon additive 0 to 10 parts by weight based on 100 parts by weight of AP are shown in [Table 5].

 Low Carbon Additives Content (phr) Asphalt before aging Asphalt After RFTO Asphalt After PAV Viscosity (120 ℃, cps) Viscosity (140 ° C, cps) G ^* / sinδ (70 ° C, kPa) G ^* / sinδ (70 ° C, kPa) Stiffness (-12 ℃, MPa) m-value (-12 ℃) 0 1150 412 0.624 1.201 189 0.33 One 950 380 1.955 2.450 185 0.33 3 900 310 3.013 3.805 180 0.33 5 850 290 4.813 5.912 176 0.34 10 810 275 6.812 7.813 173 0.35 RTFO (Rolling Thin Film Oven): Simulates the aging of the process of mixing with aggregate and moving to the site at high temperature in the initial plant during the production of asphalt mixture PAV (Pressure Aging Vessel) Evaluation of Aging of Asphalt Mixtures Over (Use of 3 parts by weight of low-carbon additives in 100 parts by weight of AP-5 in Examples and Comparative Examples) G ^* / sinδ: Factors related to plastic deformation resistance of asphalt Stiffness: Asphalt stiffness at low temperature due to flexural creep stiffness (300 MPa or less) m-value: Excessive brittle fracture due to bending creep slope (0.3 or more) The additive used is Example 2.

Through Table 5, it can be seen that the mesophilic asphalt, which changed the content of the low carbon additive of Example 2, improved high and low temperature properties as the content of the low carbon additive increased. Therefore, it is understood that the low carbon additive according to the embodiment of the present invention is preferable as an additive of the asphalt for the middle-temperature asphalt mixture because the low carbon additive plays a role of improving the plastic deformation resistance of the middle-temperature asphalt mixture and the lowering of the low-temperature physical properties as well as the viscosity-lowering effect. Can be.

(5) Performance evaluation of medium temperature asphalt mixture

Asphalt and aggregate were designed with 5.3 parts by weight of asphalt and 94.7 parts by weight of aggregate, and the low-carbon additives of Examples 1 and 2 were added at 3.0 parts by weight based on the asphalt content to produce a medium-temperature asphalt mixture.

The low temperature additive was used to prepare a moderate temperature asphalt mixture produced at a temperature of 130 ° C. (Example 1) and a heated asphalt mixture produced at a temperature of 160 ° C. without using a low carbon additive (Comparative Example 1). . Porosity tests were conducted to evaluate compactability work on road pavement sites.

division Production temperature (℃) Compaction temperature (℃) AP content (parts by weight) Low Carbon Additives (AP parts by weight) Porosity (%) Comparative Example 1 160 150 5.3 0 4.0 Example 1 130 120 5.2 3 4.1

In Example 1 and Comparative Example 1, there was a difference of about 30 ° C. in the production and compaction temperature at the time of fabrication of the specimen as shown in [Table 6], but there was almost no difference in porosity. It can be seen that it is excellent.

Next, TSR test was performed to examine the difference in moisture sensitivity as the temperature was lowered through the recovery elastic modulus test by fabricating the specimen from the medium-temperature asphalt mixture. The results are shown in [Table 7] below.

division Production temperature (℃) Compaction temperature (℃) Recovery modulus of elasticity (20 ℃, Mpa) Dynamic Stability (times / ㎜) TSR (%) Comparative Example 1 160 150 1.08 500 62 Example 1 130 120 3.18 2485 87

As can be seen from Table 7, according to Example 1 of the present invention, the recovery modulus of elasticity at room temperature was improved by about three times, and the dynamic stability at the high temperature was about 5 times. The TSR, which shows freeze-thaw and water resistance, is 1.4 times higher.

That is, the medium-temperature asphalt mixture according to Example 1 of the present invention has a much lower production and compaction temperature compared to the conventional asphalt mixture, so that energy can be saved when producing ascon according to the present invention. It can be seen that it is excellent in durability, such as deformation resistance characteristics, it is suitable as a low-carbon medium temperature asphalt mixture.

As described above, the superiority of the low carbon additive according to the present invention and the asphalt and intermediate temperature asphalt mixture prepared using the same have been described in detail through the above examples, but the present invention is not necessarily limited only by the above configuration, and the present invention. It will be appreciated that the present invention may be variously substituted, modified, and changed without departing from the spirit of the invention.

Claims (12)

In the moderate temperature asphalt prepared by adding a low carbon additive for moderate temperature asphalt to asphalt,  The neutralized asphalt is prepared by mixing the asphalt and the low carbon additive in a weight part of 100: 0.5 to 100: 15,  The low carbon additive contains polyethylene wax and vegetable wax in a weight ratio of 20: 1 to 1: 2, The vegetable wax is a modified palm wax produced by melting and reacting sodium hydroxide (NaOH) and stearic acid (CH ₃ (CH ₂ ) ₁₆ COOH) to a palm wax prepared by hydrogenating palm oil extracted from a coconut. Medium warmed asphalt prepared with a low carbon additive, characterized in that. The method of claim 1, The polyethylene-based wax has a melting point of 95 ℃ to 125 ℃, the melting temperature at 140 ℃ medium mesophilic asphalt prepared with a low carbon additive, characterized in that 400 cPs or less. The method of claim 1, wherein the vegetable wax is neutralized asphalt prepared with a low carbon additive, characterized in that the palm wax produced by the hydrogenation of palm oil (Palm oil) extracted from the coconut to the modified palm wax is further mixed. The method of claim 3, wherein The palm wax is a medium-temperature asphalt prepared with a low carbon additive, characterized in that the melting point is 55 ℃ ~ 65 ℃. delete The method of claim 1, The weight ratio of the hydrogenated palm wax and the sodium hydroxide (NaOH) is 100: 3.5 to 100: 4.0, the weight ratio of the palm wax and the stearic acid is low carbon, characterized in that 100: 16.0 to 100: 27.5 Medium temperature asphalt prepared with additives. The method of claim 1, The modified palm wax is meso warmed asphalt prepared with a low carbon additive, characterized in that the melting point of 80 ℃ ~ 110 ℃. The method of claim 1, The low carbon additive further contains an oil, wherein the weight ratio of the polyethylene wax and the oil is 20: 1 to 2: 1 meso warmed asphalt prepared by the low carbon additive. The method of claim 8, The oil is a moderate temperature asphalt prepared with a low carbon additive, characterized in that the 40 ℃ kinematic viscosity (Kinematic Viscosity) 20 ~ 300cSt. As a method of preparing a medium temperature asphalt mixture by mixing low carbon additives for asphalt, aggregate and medium temperature asphalt mixture,  Injecting the asphalt, the aggregate and the low carbon additive into an asphalt mixing plant; And  Mixing the asphalt, the aggregate, and the low carbon additive in the mixing plant at 110 ° C. to 150 ° C.,  The weight ratio of the asphalt and the low carbon additive is 100: 0.5 to 100: 15,  The low carbon additive contains polyethylene wax and vegetable wax in a weight ratio of 20: 1 to 1: 2, The vegetable wax is a modified palm wax produced by melting and reacting sodium hydroxide (NaOH) and stearic acid (CH ₃ (CH ₂ ) ₁₆ COOH) to a palm wax prepared by hydrogenating palm oil extracted from coconut. Method for producing a medium-temperature asphalt mixture using a medium-temperature asphalt, characterized in that it is prepared to contain. As a method of preparing a medium temperature asphalt mixture by mixing low carbon additives for asphalt, aggregate and medium temperature asphalt mixture,  Preparing a molten mixture by melt mixing the asphalt and the low carbon additive in an amount of 100: 0.5 to 100: 15 parts by weight;  Injecting the molten mixture and aggregate into an asphalt mixing plant and mixing at 110 ℃ to 150 ℃,  The low carbon additive contains polyethylene wax and vegetable wax in a weight ratio of 20: 1 to 1: 2, The vegetable wax is a modified palm wax produced by melting and reacting sodium hydroxide (NaOH) and stearic acid (CH ₃ (CH ₂ ) ₁₆ COOH) to a palm wax prepared by hydrogenating palm oil extracted from coconut. Method for producing a medium-temperature asphalt mixture using the medium-temperature asphalt, characterized in that it is prepared to contain. 12. The method of claim 10 or 11, wherein the asphalt and aggregate is mixed with 3.5 to 8.0 parts by weight of asphalt and 92.0 to 96.5 parts by weight of aggregate.