CN111470798B - Long-acting slow-release black anti-freezing ice modifier for asphalt pavement and preparation method thereof - Google Patents

Abstract

The invention relates to a long-acting slow-release black anti-freezing modifier for an asphalt pavement and a preparation method thereof. The black anti-freezing modifier comprises salt storage particles containing metal salt and adsorptive substances, and a coating material existing on the surfaces of the salt storage particles, wherein the coating material comprises an asphalt material and an elastomer. The black anti-freezing modifier is suitable for climatic characteristics in various countries, and has excellent anti-freezing property, slow release property and durability, so that the problem of road surface reflection caused by salt precipitation and white exposure can not be caused even when the black anti-freezing modifier is not uniformly mixed with the asphalt mixture or the formed anti-freezing road surface is used for a long time.

Description

Long-acting slow-release black anti-freezing ice modifier for asphalt pavement and preparation method thereof

Technical Field

The invention relates to a long-acting slow-release black anti-freezing modifier for an asphalt pavement and a preparation method thereof.

Background

The problem that the road traffic safety is disturbed by the ice accumulated on the road surface in winter is always. The ice accumulated on the road surface can cause the anti-skid capability of the road surface to be greatly reduced, thereby weakening the traffic capacity of the road, easily causing malignant traffic accidents, damaging the road and the accessory structures thereof, causing traffic interruption in serious cases, causing the life and production of people to be unable to be normally carried out, and even harming the safety of life and property of people.

At present, the common methods for removing ice and snow on the road surface are generally divided into two types, namely a passive inhibition type and an active ice and snow melting type. The commonly adopted passive inhibition type ice and snow removing measures mainly comprise measures of spreading a snow melting agent, manually removing snow, mechanically removing snow and the like. The main components of the metal chloride snow-melting agent which is usually scattered are sodium chloride, calcium chloride, magnesium chloride, potassium chloride and the like, which can not only ensure smooth traffic and safe driving, but also corrode infrastructure and destroy the environment. The manual snow removal and the mechanical snow removal are low in efficiency and long in time consumption, and particularly, professional snow removal equipment needs to be purchased for the mechanical snow removal, so that the road surface is damaged. The active ice and snow melting technology mainly realizes ice and snow melting through special functions of the road surface, and comprises a self-stress elastic road surface paving technology, an energy conversion type ice and snow melting technology and the like. The active ice and snow melting type technique is not yet mature, and the actual operation is difficult.

After long-time scientific research and application, the anti-icing asphalt pavement technology is considered to be a more reasonable technology under the condition of considering cost, maintenance, action time and use effect. The anti-freezing asphalt pavement is a pavement with a freezing-inhibiting effect formed by directly mixing an anti-freezing modifier with a freezing-inhibiting effect into an asphalt mixture. The anti-freezing modifier is simple and convenient to use, and can be added into the mixture in advance before asphalt pavement laying or overhaul and used for asphalt pavement laying. The main action principle of the prior anti-freezing modifier is that under the action of capillary pressure and vehicle rolling, salt in the asphalt mixture is gradually separated out, so that the freezing point of ice and snow on the surface of a road is reduced, and the icing of the snow on the surface area of the road is delayed; at the same time, the metal salt can melt the ice at a lower temperature for easy removal.

Verglimit antifreeze was first developed in Switzerland, Germany and the like, and can effectively prevent and delay the pavement as an additive for salt-storing pavement. The product is modified subsequently, and finally the V-260 which is relatively mature now is developed. The product has good high temperature resistance, and can replace aggregates with corresponding particle sizes in the mixture, and the asphalt mixture formed by mixing and rolling has good high and low temperature performance, but the water stability is slightly worse than that of the common mixture. There is a certain amount of research on the chemical anti-freezing road surface technology in Japan. However, the types of the anti-icing modifier products are few in all countries in the world at present, and the fact that the existing anti-icing modifier is not suitable for treating the accumulated snow and ice condition of the road surface in China is found in practical use.

At present, certain research is also made on an anti-freezing modifier in China, however, in the aspect of effectively controlling the release of the ice melting material in the pavement, the prior art still has a space for improvement.

For example, patent document 1 discloses an anti-freezing modifier in which calcium magnesium acetate is supported on the surface of diatomaceous earth and hydrophobically modified with methyltriethoxysilane. Although the anti-freezing ice modifier can delay the release of salt, the salt carrying amount of the anti-freezing ice modifier is small and the slow release effect is insufficient.

For example, patent document 2 discloses a long-acting, slow-release snow-melting agent containing lignin-coated calcium chloride. Although patent document 2 states that the life of the snow-melting agent can be up to 15 years or more, the theoretical life is lost in practical use because lignin is soluble in water.

For example, patent document 3 discloses a coating type long-acting anti-icing modifier comprising a large-particle salt, a cured coating made of a phenol resin or an epoxy resin, and a salt storage carrier. Although it has a good slow-release effect, it is insufficient due to the low temperature resistance of the phenolic resin or epoxy resin and its affinity with asphalt pavement. Therefore, under a low temperature environment in winter, the anti-ice freezing modifier is difficult to maintain durability upon repeated rolling of vehicles, and even causes pavement cracking.

For example, patent document 4 discloses a self-melting ice asphalt mixture additive comprising plastic slow-release particles and rubber particles formed by co-extruding a salt and a plastic. Similarly to the case of patent document 3, this additive has room for improvement in low temperature resistance and affinity with asphalt pavement.

As described above, in the case where the formed anti-freezing road surface is repeatedly rolled by vehicles and subjected to high temperatures in summer and low temperatures in winter when used for a long period of time, the conventional anti-freezing modifier has insufficient durability, resulting in that when the road surface encounters rain and snow, salt in the anti-freezing modifier is largely precipitated in a short time, a large amount of crystallized salt particles are formed, and the road surface and the surrounding environment are polluted.

Furthermore, all anti-icing modifiers currently on the market are white (as in the above-mentioned patent documents), which leads to white particles being exposed on the asphalt pavement during the paving process, especially in the case of non-uniform mixing of the asphalt mixture (white-exposed phenomenon). Meanwhile, precipitation and whitening of salts due to poor durability of the anti-icing modifier also cause road surface reflection. Under the stimulation of strong light reflection, the binocular pain of a driver is easy to cause, the lacrimation sight is blurred, and then traffic accidents are caused to occur frequently, the traffic accident rate is obviously increased in ice and snow days, and the safety driving is not facilitated.

Documents of the prior art

Patent document 1: CN107522430A

Patent document 2: CN106630735A

Patent document 3: CN107057642A

Patent document 4: CN108107303A

Disclosure of Invention

Problems to be solved by the invention

In view of the above problems, it is an object of the present invention to provide a black anti-icing modifier which is suitable for climate characteristics in various regions of China, has excellent anti-icing properties, sustained release properties, and durability, and thus does not cause a problem of road surface reflection due to salt precipitation and white exposure even when the black anti-icing modifier is not uniformly mixed with an asphalt mixture or a formed anti-icing road surface is used for a long period of time. Meanwhile, the invention also aims to provide a method for preparing the black anti-icing modifier.

Means for solving the problems

The present invention has been made through intensive studies by the inventors of the present invention, and is specifically as follows.

[1] A black anti-freezing modifier comprising:

salt-accumulating particles comprising a metal salt and an adsorptive substance,

a coating material present on a surface of the salt storage particles,

wherein the coating material comprises a bituminous material and an elastomer.

[2] The black anti-icing modifier according to [1], wherein the metal salt is at least one selected from the group consisting of an alkali metal chloride, an alkali metal formate, an alkali metal acetate, an alkaline earth metal chloride, an alkaline earth metal formate and an alkaline earth metal acetate.

[3] The black anti-icing modifier according to [1] or [2], wherein the adsorptive substance exhibits a black color.

[4] The black anti-icing modifier according to [3], characterized in that the adsorptive substance is at least one selected from carbon black, attapulgite, mica, bentonite, montmorillonite, diatomaceous earth and fly ash.

[5] The black anticoagulation ice modifier according to any one of [1] to [4], wherein the content of the coating material is 50 to 300 parts by mass with respect to 100 parts by mass of the salt-accumulating particles.

[6] The black anticoagulation ice modifier according to any one of [1] to [5], wherein the content of the asphalt-based material in the coating material is 0.5 to 30 parts by mass relative to 100 parts by mass of the elastomer.

[7] The black anticoagulation ice modifier according to any one of [1] to [6], wherein the salt-accumulating particles further contain an asphalt-based binder.

[8] The black anticoagulation ice-modifying agent according to any one of [1] to [7], which has a particle size of 5mm or less.

[9] A method of making a black anti-coagulant ice modifier, the method comprising:

step 1), mixing and drying raw materials containing metal salt and adsorptive substances in the presence of an organic solvent to obtain salt-storage particles;

and 2) mixing the salt storage particles with an asphalt material and an elastomer in the presence of an organic solvent to enable the asphalt material and the elastomer to be present on the salt storage particles, and drying and granulating to obtain the black anti-freezing ice modifier.

[10] The production method according to [9], wherein the raw material in the salt-accumulating granule preparation step further includes an asphalt-based binder.

ADVANTAGEOUS EFFECTS OF INVENTION

The invention provides a black anti-freezing modifier for asphalt pavement, which is suitable for various climatic characteristics of China. The black anti-icing modifier is friendly to the surrounding environment, has excellent anti-icing performance at a low temperature of 0 to-30 ℃, can greatly slow down the speed of releasing metal salt, has excellent slow release performance, has good stress resistance, hydrophobicity and affinity with an asphalt pavement due to the coating material containing the asphalt material and the elastomer, can maintain the slow release effect even when a vehicle is repeatedly rolled and experiences high temperature in summer and low temperature in winter, and has excellent durability. Therefore, even when the black anti-icing modifier is not uniformly mixed with the asphalt mixture or the formed anti-icing road surface is used for a long time, the problem of road surface reflection due to precipitation of salt and white dew does not occur.

Detailed Description

Exemplary embodiments of the present invention are described below, however, it is to be understood that the present invention is not limited to the following embodiments.

< Black anti-icing modifier >

The black anti-freezing modifier comprises: salt-accumulating particles comprising a metal salt and an adsorptive substance, a coating material present on a surface of the salt-accumulating particles, wherein the coating material comprises a bituminous material and an elastomer.

The components constituting the black anti-freezing modifier will be described below.

< salt storage particles >

Metal salt

The metal salt is an effective ingredient of the black anti-freezing modifier of the present invention, and is used to adjust the freezing point of water on the road surface to provide excellent anti-freezing properties. The metal salt of the present invention is not particularly limited as long as it may be any known metal salt used in the art for adjusting the freezing point of water on road surfaces. From the viewpoint of better providing anti-icing property and easier availability, the metal salt of the present invention is at least one selected from the group consisting of alkali metal chlorides, alkali metal formates, alkali metal acetates, alkaline earth metal chlorides, alkaline earth metal formates, and alkaline earth metal acetates. More preferably, the metal salt of the present invention is at least one selected from the group consisting of sodium chloride, potassium chloride, calcium chloride, magnesium chloride, potassium formate, sodium formate, calcium formate, magnesium formate, potassium acetate, sodium acetate, magnesium acetate, and calcium acetate.

The ratio of each metal salt constituting the metal salt of the present invention is not limited, and may be appropriately selected in accordance with the use temperature of the black anticoagulation ice-modifying agent of the present invention. For example, the mass ratio of sodium chloride/calcium chloride or magnesium chloride may be 60-90/40-10, preferably 55-85/45-15, more preferably 50-80/50-20 at a use temperature of 0 to-10 deg.C for a black anti-freezing ice modifier; and when the using temperature of the black anti-freezing ice modifier is lower than-10 ℃, the mass ratio of the sodium chloride to the calcium chloride or the magnesium chloride is 10-40/90-60, preferably 15-35/85-55, and more preferably 20-30/80-70.

The metal salts of the present invention may be commercially available, preferably commercial grade metal salts.

In addition, the shape of the metal salt particles is not particularly limited. The size of the metal salt of the present invention is preferably 10 to 200 mesh, more preferably 20 to 150 mesh, still more preferably 30 to 100 mesh. When the size of the metal salt of the present invention is within the above range, the metal salt of the present invention can better adhere an adsorptive substance and the resulting black anti-freezing ice modifier has more excellent sustained release property, durability, and even when the metal salt is gradually consumed, voids generated in the asphalt pavement do not impair the performance of the asphalt pavement.

Adsorptive substances

The adsorptive substance of the present invention is used to adhere to the metal salt of the present invention, thereby allowing the resulting black anti-icing modifier to have excellent anti-icing properties, sustained release properties, and durability at the same time. The adsorbent of the present invention is preferably an adsorbent exhibiting a black color. The term "appear black" in the present invention can be understood as a color that is difficult for the human eye to distinguish from black.

The adsorptive substance may be any material as long as it can effectively adhere to the metal salt of the present invention and can make the anti-freezing modifier of the present invention appear black. Specific examples of the adsorptive substance include carbon black, attapulgite, mica, bentonite, montmorillonite, diatomaceous earth, fly ash. The adsorptive substance of the present invention is preferably carbon black from the viewpoint of more excellent anti-icing property, sustained release property, and durability and cost reduction of the obtained black anti-icing modifier.

The adsorptive substance of the present invention may also be subjected to various conventional modification treatments such as acid modification, salt modification, organic modification and the like, within a range not to impair the effects of the present invention, thereby improving the adsorptivity of the adsorptive substance and changing the properties of the surface of the adsorptive substance according to actual needs.

In addition, the particle size of the adsorptive substance of the present invention is preferably 20 to 600nm, more preferably 50 to 400nm, and still more preferably 100 to 300 nm. When the size of the adsorptive substance of the present invention is within the above range, the obtained black anti-icing modifier can have more excellent sustained release property, anti-icing property, and durability.

The route of obtaining the adsorbent material of the present invention is not particularly limited, and may be commercially available.

In the present invention, the mass ratio of the metal salt to the adsorptive substance is preferably 1:5 to 1:30, more preferably 1:8 to 1:25, still more preferably 1:10 to 1:22, and yet more preferably 1:18 to 1:20, from the viewpoint of providing the obtained black anticoagulation modifier with more excellent anticoagulation property, sustained release property, and durability.

Asphalt binder

The salt-accumulating granules of the present invention preferably further comprise a pitch-based binder. When the salt-storage particles contain an asphalt binder, the asphalt binder can pre-encapsulate the metal salt and the adsorptive substance, improve the affinity between the metal salt and the adsorptive substance and the coating material, and reduce the internal stress of the black anti-icing modifier, thereby further improving the slow release property, durability, and the like of the obtained black anti-icing modifier.

Examples of the pitch-based binder include at least one of pitch, asphalt, tar pitch, coal tar, coal pitch, and modified products thereof. More preferably, the bituminous binder of the present invention is bitumen.

In the case of using the asphalt-based binder, the mass ratio of the adsorptive substance to the asphalt-based binder in the salt-accumulating particles of the present invention is preferably 0.2:1 to 1:4, more preferably 0.5:1 to 1:2.5, and still more preferably 1:1 to 1:2.

Other Components

The adsorptive substance of the present invention may include any other component such as thermoplastic or thermosetting resins, rubbers, thermoplastic elastomers, phase change materials, non-black adsorptive substances, waxes, surface treatment agents, ultraviolet absorbers, preservatives, antibacterial agents, flame retardants, etc., as needed, in addition to the metal salt, the adsorptive substance, and the asphalt-based binder further contained, within a range not impairing the effects of the present invention.

< coating Material >

The coating material of the present invention is present on the surface of the salt-storing particle, and specifically, depending on the specific production method, the coating material may be present on the entire surface of the salt-storing particle or may be present in a part of the surface of the salt-storing particle.

In the present invention, the coating material may include a bituminous material and an elastomer. In the present invention, by including the asphalt-based material and the elastomer in the covering material, the bleeding of the metal salt can be satisfactorily controlled, thereby obtaining excellent sustained-release properties; the encapsulation of the salt storage particles can be realized, so that the black anti-freezing ice modifier disclosed by the invention is environment-friendly. The coating material also provides good hydrophobicity, good compatibility with asphalt for road surfaces, good low temperature stress resistance, is capable of maintaining excellent sustained release properties even when vehicles repeatedly crush road surfaces and experience high temperatures in summer and low temperatures in winter, even though the anti-freezing modifier has excellent durability.

The content of the coating material is preferably 50 parts by mass to 300 parts by mass, more preferably 80 parts by mass to 250 parts by mass, and still more preferably 100 parts by mass to 200 parts by mass, relative to 100 parts by mass of the salt-storing particles. When the content of the coating material is more than the above range, the anti-icing property of the obtained black anti-icing modifier tends to deteriorate. When the content of the coating material is less than the above range, the resulting black anti-freezing modifier modified sustained release property, durability, tends to deteriorate.

Asphalt material

Examples of the bituminous material in the coating material of the present invention are the same as those listed for the bituminous binder described above. In the present invention, it is more preferable that the bituminous material in the coating material is the same as the bituminous binder; most preferably, the same materials are used for the bituminous material in the coating material, the bituminous binder mentioned above and the bituminous material in the road surface.

Elastic body

In the present invention, the term "elastomer" is a concept covering natural rubber, synthetic vulcanized rubber, and thermoplastic elastomers, but does not include thermoplastic or thermosetting resins. Examples of the synthetic vulcanized rubber include styrene-butadiene rubber (SBR), nitrile rubber, butyl rubber, chloroprene rubber, isoprene rubber, butadiene rubber, ethylene-propylene-diene rubber, and silicone rubber. Examples of the thermoplastic elastomer include olefin-based thermoplastic elastomers, styrene-based thermoplastic elastomers, polyamide-based thermoplastic elastomers, polyester-based thermoplastic elastomers, polyvinyl chloride-based thermoplastic elastomers, polyurethane-based thermoplastic elastomers, fluoropolymer-based thermoplastic elastomers, and the like.

The elastomer of the present invention is preferably a styrene-based elastomer, for example, styrene-butadiene rubber (SBR), styrene-butadiene-styrene copolymer (SBS), styrene-isoprene-styrene copolymer (SIS), styrene-ethylene-butylene-styrene copolymer (SEBS), styrene-ethylene-propylene-styrene copolymer (SEPS), styrene-isoprene copolymer, styrene-isoprene-butadiene-styrene copolymer, styrene-propylene-butylene-styrene copolymer, styrene-hexene-butene-styrene copolymer, and the like, from the viewpoint of imparting more excellent anti-icing property, sustained release property, and durability to the obtained black anti-icing modifier. These examples may be used alone or in a combination of two or more. More preferably, the elastomer of the present invention is at least one selected from the group consisting of styrene-butadiene rubber (SBR), styrene-butadiene-styrene copolymer (SBS), styrene-isoprene-styrene copolymer (SIS), styrene-ethylene-butylene-styrene copolymer (SEBS), and styrene-ethylene-propylene-styrene copolymer (SEPS).

The elastomer of the present invention can be obtained by a commercial method without any particular limitation.

In the covering material, the content of the asphalt-based material is preferably 0.5 to 30 parts by mass, more preferably 1 to 25 parts by mass, and still more preferably 2 to 22 parts by mass, relative to 100 parts by mass of the elastomer. When the content of the asphalt-based material is more than the above range, the resulting black anti-freezing modifier tends to deteriorate in the sustained-release property and durability. When the content of the asphalt-based material is less than the above range, the affinity of the resulting black anti-icing modifier with the road surface also tends to deteriorate.

Other Components

The covering material of the present invention may include, in addition to the elastomer and the asphalt-based material, any other component such as thermoplastic or thermosetting resin, phase change material, wax-based, surface treatment agent, ultraviolet ray adsorbent, preservative, antibacterial agent, flame retardant, etc., as needed within a range not to impair the effects of the present invention.

< method for producing Black anticoagulation Ice modifier >

The method for producing the black anticoagulation ice modifier of the invention is a method for producing the black anticoagulation ice modifier. The method comprises the following steps: a salt-storage particle preparation step of mixing and drying raw materials including metal salts and adsorptive substances in the presence of an organic solvent to obtain salt-storage particles; and a coating step, namely mixing the salt storage particles with an asphalt material and an elastomer in the presence of an organic solvent so that the asphalt material and the elastomer are present on the salt storage particles, and drying and granulating to obtain the black anti-freezing ice modifier.

The steps are specifically described below.

Salt-accumulating particle preparation step

In the salt-accumulating particle production step of the present invention, raw materials including a metal salt and an adsorptive substance are mixed and dried in the presence of an organic solvent to obtain salt-accumulating particles.

The organic solvent in this step may be any organic solvent. Specific examples of the organic solvent include formamide, trifluoroacetic acid, dimethyl sulfoxide (DMSO), acetonitrile, N-Dimethylformamide (DMF), hexamethylphosphoramide, methanol, ethanol, acetic acid, isopropanol, pyridine, tetramethylethylenediamine, acetone, triethylamine, N-butanol, dioxane, tetrahydrofuran, methyl formate, tributylamine, methyl ethyl ketone, ethyl acetate, chloroform, trioctylamine, dimethyl carbonate, diethyl ether, isopropyl ether, N-butyl ether, trichloroethylene, diphenyl ether, dichloromethane, toluene, carbon tetrachloride, carbon disulfide, cyclohexane, hexane. These organic solvents may be used alone or in combination of two or more.

The amount of the organic solvent used is 2 to 30 times, preferably 3 to 20 times, the total mass of the metal salt and the adsorptive substance from the viewpoint of easy production.

The mixing equipment used in this step is not particularly limited, and may be appropriately selected according to actual needs. Preferably, from the viewpoint of sufficiently contacting the metal salt and the adsorptive substance, the stirring speed may be 100-; the mixing time is 1 minute to 2 hours.

In some preferred embodiments, the salt-accumulating particle preparing step further comprises: mixing the metal salt and the adsorptive substance, and then adding an asphalt binder, mixing, drying, and granulating. In this case, not only can the obtained black anti-icing modifier have more excellent anti-icing property, sustained release property and durability, but also the production time of the black anti-icing modifier can be reduced to improve the productivity. In this case, the organic solvent used in the present step is a solvent capable of dissolving the asphalt binder. Meanwhile, in this case, the stirring speed when mixing the asphalt binder can be 500-3000r/min, and more preferably 800-2000 r/min; the mixing time in mixing the asphalt binder is 1 minute to 2 hours, and more preferably 5 minutes to 1 hour.

The drying temperature for removing the organic solvent used in this step is preferably 20 to 60 ℃, and from the viewpoint of reducing the production cost and facilitating mass production, it is preferable to dry at room temperature (e.g., 25 ℃). In preferred embodiments using a bituminous binder, the drying temperature for removing the organic solvent is generally below the melting point of the bituminous binder. Air blowing equipment may be used as needed during the drying process.

The size of the salt accumulation particles obtained in this step is not particularly limited, and preferably, the size of the salt accumulation particles is such that the particle size of the formed anti-freezing ice modifier is 5mm or less.

The metal salt, the adsorptive substance and the further bituminous binder used in this step have been described in detail above and will not be described in detail here.

Coating step

The coating step of the present invention is a step for causing a coating material to be present on the surface of the salt-storing particles.

Specifically, in the coating step, the salt-accumulating particles are mixed with an asphalt material and an elastomer in the presence of an organic solvent so that the asphalt material and the elastomer are present on the salt-accumulating particles, and the mixture is dried and granulated to obtain the black anti-freezing ice modifier.

Specific examples of the organic solvent in this step are the same as those in the salt-accumulating particle preparation step. The organic solvent used in this step may be the same as or different from the organic solvent used in the salt-accumulating particle preparation step. Preferably, the organic solvent in this step can dissolve the bituminous material and the elastomer.

Preferably, the raw material of the coating material may be dissolved in an organic solvent in advance from the viewpoint of sufficiently contacting the salt-accumulating particles and the coating material.

The mixing equipment used in this step is not particularly limited, and may be appropriately selected according to actual needs. Preferably, from the viewpoint of sufficiently contacting the salt-storage particles and the coating material, the mixing speed may be 100-; the mixing time is 0.5 minutes to 2 hours.

In some preferred embodiments, where the salt-accumulating particles comprise an asphalt binder, the mixing time is preferably from 0.5 to 5 minutes, more preferably from 1 to 4 minutes, to inhibit the loss of asphalt binder that may result from dissolution during this step while ensuring that the salt-accumulating particles are adequately coated with the coating material.

The bituminous material and the elastomer used in this step have been described in detail above and will not be described in detail here.

The drying temperature for removing the organic solvent is preferably 20 to 60 ℃, and from the viewpoint of reducing the production cost and facilitating mass production, it is preferable to dry at room temperature (about 25 ℃). Air blowing equipment may be used as needed during the drying process.

The shape of the black anti-freezing modifier is not particularly limited. After granulation, the particle size of the obtained black anti-freezing ice modifier is preferably 5mm or less, and more preferably 3mm or less, and thus even when the metal salt is gradually consumed, voids generated in the asphalt pavement do not impair the performance of the asphalt pavement.

Other steps

In addition to the above steps, the method for producing the black anti-icing modifier of the invention may further include classifying, metering, packaging, etc. the obtained black anti-icing modifier as needed.

Examples

Embodiments of the present invention will be illustrated below by way of examples, but the present invention is not limited to these specific examples. The proportional contents in the examples are based on mass unless otherwise specified.

Example 1

Calcium chloride, magnesium chloride and sodium chloride (all commercial grade, 2:2:6) were added to tetrahydrofuran (10 times the amount added to the solid blend material) at a ratio of 1:15 with carbon black and stirred at 300r/min for 30 min. Subsequently, tetrahydrofuran was removed at normal temperature to obtain salt-accumulating particles.

At normal temperature, fully stirring and dissolving asphalt, SBS and SBR (1:50:25) in tetrahydrofuran, adding the salt storage particles, stirring at 100r/min for 30min, fully stirring and coating. Then dried at 60 ℃, and granulated and sieved to make the particle size of the black anti-freezing modifier below 5 mm. The coating material was weighed out to be about 100 parts by mass with respect to 100 parts by mass of the salt-storing particles.

And cooling the dried material to room temperature, and metering and packaging to obtain the black anti-freezing ice modifier.

Example 2

Potassium acetate and potassium formate (4:6) were added to tetrahydrofuran (10 times the amount of solid blend) at a ratio of 1:15 with carbon black and stirred at 300r/min for 30 min. Subsequently, tetrahydrofuran was removed at normal temperature to obtain salt-accumulating particles.

At normal temperature, fully stirring and dissolving asphalt, SIS and SBS (1:50:25) in tetrahydrofuran, adding the salt storage particles, stirring at 100r/min for 30min, fully stirring and coating. Then dried at 60 ℃, and granulated and sieved to make the particle size of the black anti-freezing modifier below 5 mm. The coating material was weighed out to be about 120 parts by mass with respect to 100 parts by mass of the salt-accumulating particles.

And cooling the dried material to room temperature, and metering and packaging to obtain the black anti-freezing ice modifier.

Example 3

Except that after calcium chloride, magnesium chloride and sodium chloride were mixed with carbon black in tetrahydrofuran, pitch (pitch: carbon black ═ 1:1) was further added thereto and stirred at 1500r/min for 15 min; and the coating time was changed from 30min to 3min, a black anti-freezing modifier was obtained in the same manner as in example 1. The coating material was weighed out to be about 67 parts by mass with respect to 100 parts by mass of the salt-accumulating particles.

Example 4

Except that after potassium acetate and potassium formate were mixed with carbon black in tetrahydrofuran, pitch (pitch: carbon black ═ 1:1) was further added thereto and stirred at 1500r/min for 15 min; and the coating time was changed from 30min to 3min, a black anti-freezing modifier was obtained in the same manner as in example 2. The coating material was weighed out to be about 90 parts by mass with respect to 100 parts by mass of the salt-accumulating particles.

Example 5

A black anti-freezing modifier was obtained in the same manner as in example 3, except that the coating material was replaced with asphalt, a polyurethane elastomer, and SBS. The coating material was weighed out to be about 86 parts by mass with respect to 100 parts by mass of the salt-accumulating particles.

Example 6

A black anti-freezing modifier was obtained in the same manner as in example 3, except that the coating time was changed from 3min to 10 min. The coating material was weighed out to be about 80 parts by mass with respect to 100 parts by mass of the salt-accumulating particles.

Example 7

A black anti-freezing modifier was obtained in the same manner as in example 3, except that the coating time was changed from 3min to 0.5 min. The coating material was weighed out to be about 46 parts by mass with respect to 100 parts by mass of the salt-accumulating particles.

Comparative example 1

A black anti-freezing modifier was obtained in the same manner as in example 1, except that the coating material was not included.

Comparative example 2

A black anti-freezing modifier was obtained in the same manner as in example 1, except that the coating material did not contain asphalt.

Comparative example 3

A black anti-freezing modifier was obtained in the same manner as in example 1, except that the coating material did not contain SBS and SBR. In other words, only the salt-accumulating granules in example 1 were coated with asphalt.

Comparative example 4

A black anti-freezing modifier was obtained in the same manner as in example 1, except that the coating step was changed to mixing the salt-accumulating particles with paraffin under heating (i.e., the coating material was changed to paraffin).

Comparative example 5

A black anti-freezing modifier was obtained in the same manner as in example 1, except that the coating step was changed to melt-extruding the salt-accumulating particles and the polyethylene resin using an extruder (i.e., the coating material was changed to a polyethylene resin).

Comparative example 6

A black anti-freezing modifier was obtained in the same manner as in example 1, except that the coating step was changed to mixing the salt-accumulating particles and the water-soluble phenol resin in anhydrous ethanol and then curing at 100 ℃ (i.e., the coating material was changed to a cured phenol resin).

Performance testing

Sustained release property

Placing the heated coarse and fine aggregates in a mixer, and properly mixing the coarse and fine aggregates by using a small shovel; then adding asphalt, starting a mixer to stir while inserting a mixing blade into the mixture to mix for 1-1.5 min; and (3) suspending mixing, adding the heated mineral powder and the anti-freezing modifier, continuing to mix until the mixture is uniform, and keeping the asphalt mixture within the required mixing temperature range (the standard total mixing time is 3min), thereby obtaining the anti-freezing asphalt mixture (the actual mixing amount of the black anti-freezing modifier is 5.25 mass%). Further, a marshall test piece of the anti-freezing asphalt mixture was prepared. The test piece was entirely soaked in purified water at room temperature for 20 days, and the concentration of anions derived from the metal salt in the water was measured every day. The anion measurement method selected varies depending on the kind of anion to be measured, and is a method well known in the art.

When the anion concentration in the water reaches a plateau, it is assumed that all of the salt that could be leached has been extracted. It is generally believed that the longer the time it takes to reach a plateau (hereinafter referred to as the equilibration time), the lower the peak concentration, which means that the more anti-freezing modifier remains in the mix, the better the sustained release.

The following table 1 shows exemplary results obtained by performing the above-described tests on example 1 and example 3. Since metal chloride was used as the metal salt in examples 1 and 3, the change of chloride ion in the solution was measured using a chloride ion content rapid tester.

TABLE 1 immersion results of anti-freezing asphalt mixture test pieces

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For each of examples and comparative examples, evaluation was performed based on the following criteria.

Very good: the equilibrium time is more than 15 days, and the peak concentration is extremely low.

O: the equilibrium time is more than 12 days and less than 15 days, and the peak concentration is low.

And (delta): the equilibrium time is more than 8 days and less than 12 days, and the peak concentration is lower.

X: the equilibration time was less than 8 days and the peak concentration was high.

Durability

And preparing a rut plate test piece of the anti-freezing asphalt mixture. In the process of preparing the test piece, the total weight of each rutting plate is 10500g, and the actual mixing amount of the black anti-freezing modifier is 5.25 mass percent, namely the content of the black anti-freezing modifier in each rutting test piece is 551.25 g.

In order to simulate the environment of a real asphalt pavement, an acceleration loading device is used for rolling on a track plate test piece, and meanwhile, a dynamic water simulation test is carried out on the track plate according to the annual average rainfall so as to determine the loss condition of the black anti-freezing modifier.

The test steps are as follows:

preparing three rut plates at each temperature, and soaking the rut plates in purified water at the temperature of-10 ℃, 0 ℃, 5 ℃, 15 ℃, 25 ℃ and 35 ℃ respectively;

secondly, spraying water for the rut plate for 10 times by using a spraying device simulating a real rainfall process according to the annual average rainfall of a test section area (72L) until the rainfall is reached;

measuring the total content of anions in the water after 10 times of water and calculating the residual amount of the black anti-icing modifier.

Further, the theoretical age of the black anti-freezing ice modifier that is continuously released at various temperatures is calculated as the annual loss.

The results obtained by carrying out the above-described test on example 3 are given in table 2 below. Since metal chloride was used as the metal salt in example 3, the change of chloride ion in the solution was measured using a rapid chloride ion content tester.

TABLE 2

The tests described above were performed on the anti-freezing modifiers obtained in the examples and comparative examples, and the evaluation results are shown in table 3.

TABLE 3

The above embodiments are merely examples provided for clarity of explanation and are not intended to limit the present invention. It will be apparent to those skilled in the art that various other changes and modifications can be made without departing from the spirit and scope of the invention. And are neither required nor exhaustive of all embodiments. And obvious variations or modifications are therefore intended to be included within the scope of the present invention.

Claims (9)

1. A black anti-freezing modifier, comprising:

salt-accumulating particles comprising a metal salt and an adsorptive substance,

a coating material present on a surface of the salt storage particles,

wherein the coating material comprises asphalt material and elastomer,

in the coating material, the content of the asphalt material is 0.5-30 parts by mass relative to 100 parts by mass of the elastomer,

the elastomer is a styrene elastomer.

2. The black anti-icing modifier according to claim 1, wherein the metal salt is at least one selected from the group consisting of an alkali metal chloride, an alkali metal formate, an alkali metal acetate, an alkaline earth metal chloride, an alkaline earth metal formate, and an alkaline earth metal acetate.

3. The black anticoagulation ice-modifying agent according to claim 1 or 2, wherein said adsorptive substance exhibits a black color.

4. The black anti-icing modifier according to claim 3, wherein the adsorptive material is at least one selected from carbon black, attapulgite, mica, bentonite, montmorillonite, diatomaceous earth and fly ash.

5. The black anticoagulation ice modifier according to claim 1 or 2, wherein the content of said coating material is 50 to 300 parts by mass with respect to 100 parts by mass of said salt-accumulating particles.

6. The black anticoagulant ice modifier according to claim 1 or 2, wherein the salt storage particles further comprise an asphalt binder.

7. The black anticoagulation ice-modifying agent according to claim 1 or 2, wherein the particle size of the black anticoagulation ice-modifying agent is 5mm or less.

8. A method of making a black anti-icing modifier according to any one of claims 1 to 7, wherein the method comprises:

step 1), mixing and drying raw materials containing metal salt and adsorptive substances in the presence of an organic solvent to obtain salt-storage particles;

and 2) mixing the salt storage particles with an asphalt material and an elastomer in the presence of an organic solvent to enable the asphalt material and the elastomer to be present on the salt storage particles, and drying and granulating to obtain the black anti-freezing ice modifier.

9. The manufacturing method according to claim 8, wherein the raw material in the salt-accumulating granule preparation step further includes an asphalt-based binder.