CN109665753B

CN109665753B - Direct-throwing rubber powder, asphalt mixture, pavement using mixture and processing method thereof

Info

Publication number: CN109665753B
Application number: CN201811563789.6A
Authority: CN
Inventors: 陈中秋; 李志刚; 周政; 顾兴宇; 马万; 邓宝智; 黄兆周; 武宝军; 徐磊
Original assignee: China Jiaotong Yunnan Expressway Development Co Ltd
Current assignee: China Jiaotong Yunnan Expressway Development Co Ltd
Priority date: 2018-12-20
Filing date: 2018-12-20
Publication date: 2020-03-27
Anticipated expiration: 2038-12-20
Also published as: CN109665753A

Abstract

The invention discloses a direct-throwing rubber powder, an asphalt mixture, a pavement using the mixture and a processing method thereof, wherein the asphalt mixture comprises 0.4-0.5 part by weight of the direct-throwing rubber powder, 4-5 parts by weight of asphalt and 90-95 parts by weight of mineral aggregate; the direct-throwing rubber powder comprises 90-92 parts by weight of rubber powder, 13-18 parts by weight of vermiculite, 2-4 parts by weight of aromatic oil, 2-4 parts by weight of furfural extract oil, 10-15 parts by weight of calcium oxide, 5-6 parts by weight of petroleum resin, 0.5-1 part by weight of maleic anhydride, 5-8 parts by weight of friction powder, 1-2 parts by weight of iron oxide, 2-3 parts by weight of LDPE and 0.5-1 part by weight of 1010 antioxidant. The invention carries out chemical treatment on the common rubber powder to promote the rubber powder and the asphalt to generate chemical reaction aiming at improving the performance, thereby improving the performance of the asphalt mixture produced by the dry process and meeting the technical requirements of relevant specifications.

Description

Direct-throwing rubber powder, asphalt mixture, pavement using mixture and processing method thereof

Technical Field

The invention relates to the field of building materials, in particular to direct-throwing rubber powder, an asphalt mixture, a pavement using the mixture and a processing method thereof.

Background

The SBS modified asphalt is used for thirty years, and some performance weaknesses of the SBS modified asphalt begin to emerge, such as poor low temperature, insufficient crack resistance and the like. More importantly, the sharply increased traffic volume, the increasingly large axle weight of vehicles, the overload phenomenon which is forbidden frequently, and the direct exposure of the asphalt concrete surface layer bearing the load to the temperature stress generated by the extreme change of high and low temperature, put higher requirements on the pavement material, especially the asphalt quality. In recent years, large-area early damage occurs on high-grade roads which are built to be communicated with vehicles by taking SBS modified asphalt mixture as surface materials all over the country, and the current situation that the SBS modified asphalt can not meet the requirements of modern traffic on the road performance is also intuitively explained.

The rubber asphalt used as road material has the features of high stability, high low temperature stability, high water loss resistance, high flexibility, high crack resistance, high ageing resistance, high fatigue resistance, etc. On the other hand, the automobile industry is developed rapidly, the national automobile purchasing demand is large, and the domestic automobile keeping quantity is continuously increased. However, as automobiles become more popular, garbage such as waste tires has increased. How to reduce the pollution of the waste tires to the environment is a problem which cannot be ignored and needs to be solved urgently, the recycling of the waste tires is a method for effectively solving the pollution of the waste tires, and the application of the waste tires made into rubber powder to asphalt mixtures is one of the main approaches for treating the waste tires.

At present, the application of waste rubber powder in asphalt mixture is divided into two types according to the process, one is wet method, and the other is dry method. The wet process is that waste rubber powder is added into asphalt as a modifier, and is subjected to chemical reaction to be recombined into new molecules so as to achieve the purpose of modifying the asphalt, finally the rubber asphalt is prepared, and then the rubber asphalt is mixed with aggregate to generate a rubber asphalt mixture. The rubber asphalt and the mixture thereof have excellent stability, durability, anti-sliding and noise reduction capabilities, and have been applied to a certain range in the aspects of mixtures, stress absorbing layers, sealing layers and the like abroad. Since the introduction of the 20 th century and the 80 th era into China, the wet process is comprehensively developed and paved on a plurality of highways, and favorable results are obtained. However, when the rubber asphalt is produced, the temperature of the matrix asphalt needs to be as high as 200 ℃, the due performance of the asphalt is damaged, the storage stability is poor, and the rubber asphalt needs to be used within 1-2 days; special production equipment is needed when the rubber asphalt is prepared on site, the requirement on the fineness of the rubber powder is high, the viscosity of the asphalt is high, and the difficulty is increased for construction; the wet process has high asphalt consumption, and compared with SBS modified asphalt, the technological economic benefit has no obvious advantages, so that the wet process is restricted in China and has no large-area application.

The wet process corresponds to a dry process. The method is mainly characterized in that waste rubber powder and hot mineral aggregate are mixed and then added into asphalt to obtain the rubber powder modified asphalt mixture. The dry process is relatively simple, large equipment is not needed, the production of the rubber asphalt mixture is completed in the mixing cylinder at one time, equipment and technical transformation are not basically involved, the requirement on the technical level of a construction unit is relatively low, and the rubber asphalt mixture is easily accepted by the construction unit. And the production of the dry-method rubber asphalt concrete is finished in the mixing cylinder, so that the processing process of the rubber asphalt is omitted, the environment is protected, the energy is saved, and the advantages have great attraction. However, the method for directly adding the rubber powder has limited effect on improving the performance of the asphalt pavement, the rubber powder and the asphalt have short reaction time, the direct result is that the adhesiveness between the rubber powder and the asphalt is poor, the water stability is poor, the rubber powder is generally used for replacing a part of aggregate to increase the elasticity of the mixture, and the method is mainly used for low-grade low-traffic-volume roads and some special occasions and has very limited popularization and application.

The dry method has the advantages of less pollution and convenient on-site direct casting construction, which cannot be replaced by the wet method, and the key to the application is how to make good use of the advantages and avoid the disadvantages. In recent years, German vitamin connecting agents (for short TOR) are introduced in part of China, and similar novel rubber reinforced connecting agents are independently developed in China, the adhesiveness of rubber powder and asphalt in the dry-method rubber asphalt mixture modified by the connecting agents reaches the level of SBS modified asphalt and wet-method rubber asphalt, so that the important defects of the early dry method are fully overcome by the novel dry method.

Through the practice in recent years, the rubber asphalt has the characteristics of high viscosity and high elasticity compared with SBS modified asphalt, but also has the problems of complex construction process, insufficient storage stability of wet process and less practice of dry process, and the comprehensive performance is not superior to that of SBS modified asphalt and cannot be replaced. Therefore, the SBS modified asphalt still dominates the current modified asphalt market as a mature modified asphalt technology.

How to face new demands on road performance due to modern traffic developing at speed and extreme climates. Increasing the amount of SBS does alleviate the disadvantage of SBS exposure in the aspect of current road performance to a certain extent, but this is also an innocent treatment, and the treatment is temporary and permanent. Moreover, the modified asphalt with high SBS content is difficult to process and store, needs heat preservation and regular stirring in the production and transportation processes, and invisibly increases the construction cost. Therefore, many experts and scholars at home and abroad are dedicated to exploring more effective asphalt modification technologies, and the research idea of obtaining the composite modified asphalt by fusing two asphalt modification technologies besides exploring a new modifier is in the mainstream day by day.

Because SBS modified asphalt has been used for many years and the technology is mature, the composite modified asphalt is mostly compounded on the basis of the original SBS modified asphalt, for example, fibers, rock asphalt lake asphalt, an anti-rutting agent and the like are added, and the good effect is achieved. Under the background, a method for modifying asphalt more simply and conveniently and improving the performance of the modified asphalt is particularly important.

Disclosure of Invention

The invention aims to provide direct-throwing rubber powder, an asphalt mixture, a pavement using the mixture and a processing method thereof, and solves the problem of poor performance of the conventional asphalt and the asphalt mixture.

In order to solve the technical problems, the invention adopts the following technical scheme:

an asphalt mixture comprises 0.2-0.3 weight part of direct-throwing rubber powder, 4-5 weight parts of asphalt and 90-95 weight parts of mineral aggregate.

Preferably, the mineral aggregate passes through 100%, 90% -95%, 60% -71%, 30% -41.5%, 20% -30%, 15% -22.5%, 10% -16.5%, 7% -12.5%, 5.0% -8.5% and 4% -6% in mass percentage, namely grading when the mineral aggregate is respectively sieved by sieves with 16mm, 13.2mm, 9.5mm, 4.75mm, 2.36mm, 1.18mm, 0.60mm, 0.30mm, 0.15mm and 0.075mm sieve meshes.

Preferably, the mineral aggregate passes through 100% by mass, 91% to 92% by mass, 69% to 71% by mass, 33.4% to 39.5% by mass, 26% to 27% by mass, 18.5% to 19% by mass, 12% to 13% by mass, 8.3% to 8.6% by mass, 6.5% to 7% by mass and 4.9% to 5.1% by mass when the mineral aggregate is respectively sieved by sieves with 16mm, 13.2mm, 9.5mm, 4.75mm, 2.36mm, 1.18mm, 0.60mm, 0.30mm, 0.15mm and 0.075mm mesh openings.

A processing method of asphalt mixture comprises the steps of firstly dry-mixing direct-throwing rubber powder with mineral aggregate to obtain a mixture A, and then wet-mixing the mixture A with asphalt to obtain the mixture.

Preferably, the asphalt is SBS modified asphalt, the dry mixing temperature is 180-190 ℃, and the wet mixing temperature is 170-180 ℃.

Preferably, the dry mixing time is 5-10 s, and the rotation speed of the stirring shaft is 90-130 r/min; the wet mixing time is 35 to 45s, and the rotating speed of the stirring shaft is 60 to 120 r/min.

The direct-throwing rubber powder comprises 90-92 parts by weight of rubber powder, 13-18 parts by weight of vermiculite, 2-4 parts by weight of aromatic oil, 2-4 parts by weight of furfural extract oil, 10-15 parts by weight of calcium oxide, 5-6 parts by weight of petroleum resin, 0.5-1 part by weight of maleic anhydride, 5-8 parts by weight of friction powder, 1-2 parts by weight of iron oxide, 2-3 parts by weight of LDPE and 0.5-1 part by weight of 1010 antioxidant.

Preferably, the rubber powder is 20-40 mesh truck tire rubber powder.

A processing method of direct-throwing rubber powder comprises the following steps:

mixing for the first time: mixing 90-92 parts by weight of rubber powder, 13-18 parts by weight of vermiculite, 10-15 parts by weight of calcium oxide, 0.5-1 part by weight of maleic anhydride, 5-8 parts by weight of friction powder, 1-2 parts by weight of ferric oxide, 2-3 parts by weight of LDPE and 0.5-1 part by weight of 1010 antioxidant to obtain a mixture B;

and (3) mixing for the second time: and mixing the mixture B with 2-4 parts by weight of aromatic oil, 2-4 parts by weight of furfural extract oil and 5-6 parts by weight of petroleum resin to obtain the direct-vat-set rubber powder.

Preferably, the temperature of the first mixing is 85-115 ℃, the rotating speed of the stirring shaft is 250-300 r/min, and the mixing time is 8-10 minutes; the temperature of the second mixing is 60-70 ℃, the rotating speed of the stirring shaft is 150-200 r/min, and the mixing time is 5-6 minutes.

The pavement comprises a base layer and a surface layer, wherein the base layer is a cement concrete layer, and the surface layer is formed by any asphalt mixture;

the cement concrete layer comprises 0.2-0.5 cubic meter of cement, 0.8-1 cubic meter of broken stone with the grain diameter smaller than 40mm and 0.5-0.6 cubic meter of medium net sand;

the upper surface of the base layer is provided with a reinforcing layer, and the reinforcing layer is sand stones with crushed stones with the particle size of 8-13 cm.

A method of constructing a pavement comprising the laying of a base layer, the laying of a reinforcing layer and the laying of a surface layer, wherein:

the base course is laid by uniformly mixing 0.2-0.5 cubic meter of cement, 0.8-1 cubic meter of broken stone, 0.5-0.6 cubic meter of medium clean sand and 1-1.3 cubic meters of water, and the thickness of the base course is 20-30 cm;

the reinforcing layer is laid by laying sand which is soaked in water for 20-50min on a base layer after the base layer is laid, so that the area ratio of the sand to cement concrete on the surface of the base layer is 1:0.8-1.2, and the sand is 1/2-2/3 in the base layer;

and the surface layer is laid by spraying water to the exposed parts of the base layer and the reinforcing layer in the air after the base layer is hardened to wet the parts with the thickness of 1-2cm on the surface, and then laying the asphalt mixture with the thickness of 10-15 cm.

Compared with the prior art, the invention has the beneficial effects that:

in order to enhance the road performance of the SBS modified asphalt mixture, a novel composite modified asphalt mixture is produced by a dry method direct throwing mode of directly throwing tire rubber powder into a mixing tank to be mixed with stone and then mixed with asphalt. The dry method has the advantages of less pollution and convenient on-site direct casting construction, which cannot be replaced by the wet method, but the dry method has poor adhesiveness among asphalt, rubber powder and aggregate due to short reaction time and insufficient reaction of the rubber powder and the asphalt, thereby directly influencing the service performance of the asphalt pavement. Therefore, the invention carries out chemical treatment on the common rubber powder to promote the rubber powder and the asphalt to generate chemical reaction aiming at improving the performance, thereby improving the performance of the asphalt mixture produced by the dry process and meeting the technical requirements of relevant specifications.

The stone mineral aggregate with proper grain size is selected, so that the materials can keep certain porosity after being mixed, and the asphalt can not be excessively consumed.

For the fact that the temperature of the road surface is high in summer and the road surface and tires are rubbed during braking, the instantaneous temperature of the road surface can be improved, vermiculite and friction powder are added into the direct-throwing rubber powder and have a synergistic effect with calcium oxide and iron oxide, the stability of the road surface is greatly improved, the wear rate of the road surface is reduced, and the service life is prolonged.

On the basis of using the asphalt mixture, a reinforcing layer is laid between the surface layer and the base layer, the reinforcing layer plays a role of a rivet, the base layer and the surface layer are firmly fixed together, and the strength and the stability of the pavement are improved. Care is taken to ensure that the base, reinforcing and surface layers are compacted during the laying process.

Drawings

FIG. 1 is a scanning electron microscope image of the direct-cast rubber powder of the present invention.

FIG. 2 is a scanning electron microscope image of a rubber powder for a tire of a general truck.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

Example 1:

a processing method of a direct-vat rubber powder and asphalt mixture comprises the steps of stirring 0.3 weight part of direct-vat rubber powder and 95 weight parts of mineral aggregate with gradation 1 for 10s at 180 ℃ and a rotating speed of 130r/min to obtain a mixture A, and then stirring 5 weight parts of the mixture A and SBS modified asphalt for 45s at 170 ℃ and a rotating speed of 120r/min to obtain a mixture through wet mixing;

the processing method of the direct-throwing rubber powder comprises the following steps: mixing 90 parts by weight of 20-40-mesh truck tire rubber powder, 18 parts by weight of vermiculite, 15 parts by weight of calcium oxide, 1 part by weight of maleic anhydride, 8 parts by weight of friction powder, 2 parts by weight of iron oxide, 3 parts by weight of LDPE and 1 part by weight of 1010 antioxidant to obtain a mixture B, wherein the mixing temperature is 115 ℃, the rotating speed of a stirring shaft is 300r/min, and the mixing time is 10 minutes; and mixing the mixture B with 2 parts by weight of aromatic oil, 2 parts by weight of furfural extract oil and 5 parts by weight of petroleum resin at the temperature of 60 ℃, rotating the stirring shaft at 150r/min, and mixing for 5 minutes to obtain the direct-vat-set rubber powder.

Example 2:

a processing method of a direct-vat rubber powder and asphalt mixture comprises the steps of stirring 0.2 weight part of direct-vat rubber powder and 90 weight parts of mineral aggregate 4 at 190 ℃ for 5s at a rotating speed of 90r/min to obtain a mixture A, and then stirring the mixture A and SBS modified asphalt 4 weight parts at 180 ℃ for 35s at a rotating speed of 60r/min for wet mixing to obtain a mixture;

the processing method of the direct-throwing rubber powder comprises the following steps: mixing 92 parts by weight of 20-40-mesh truck tire rubber powder, 13 parts by weight of vermiculite, 10 parts by weight of calcium oxide, 0.5 part by weight of maleic anhydride, 5 parts by weight of friction powder, 1 part by weight of iron oxide, 2 parts by weight of LDPE and 0.5 part by weight of 1010 antioxidant to obtain a mixture B, wherein the mixing temperature is 85 ℃, the rotation speed of a stirring shaft is 250r/min, and the mixing time is 8 minutes; and mixing the mixture B with 4 parts by weight of aromatic oil, 4 parts by weight of furfural extract oil and 6 parts by weight of petroleum resin at the temperature of 60 ℃, rotating the stirring shaft at 200r/min, and mixing for 6 minutes to obtain the direct-vat-set rubber powder.

Example 3:

a processing method of a direct-vat rubber powder and asphalt mixture comprises the steps of stirring 0.23 weight part of direct-vat rubber powder and 92 weight parts of mineral aggregate of gradation 2 at 183 ℃ for 7s at a rotating speed of 105r/min to obtain a mixture A, and then stirring 4.3 weight parts of the mixture A and SBS modified asphalt at 173 ℃ for 38s at a rotating speed of 80r/min for wet mixing to obtain a mixture;

the processing method of the direct-throwing rubber powder comprises the following steps: mixing 90.7 parts by weight of 20-40-mesh truck tire rubber powder, 14 parts by weight of vermiculite, 12 parts by weight of calcium oxide, 0.7 part by weight of maleic anhydride, 6 parts by weight of friction powder, 1.3 parts by weight of iron oxide, 2.3 parts by weight of LDPE and 0.7 part by weight of 1010 antioxidant to obtain a mixture B, wherein the mixing temperature is 95 ℃, the rotating speed of a stirring shaft is 260r/min, and the mixing time is 8.7 minutes; and mixing the mixture B with 2.8 parts by weight of aromatic oil, 2.8 parts by weight of furfural extract oil and 5.3 parts by weight of petroleum resin at 63 ℃, wherein the rotation speed of a stirring shaft is 170r/min, and the mixing time is 5.3 minutes, so as to obtain the direct-vat-set rubber powder.

Example 4:

a processing method of a direct-vat rubber powder and asphalt mixture comprises the steps of stirring 0.27 weight part of direct-vat rubber powder and 93 weight parts of mineral aggregate of gradation 3 for 8s at 186 ℃ and at a rotating speed of 120r/min to obtain a mixture A, and then stirring 4.7 weight parts of the mixture A and SBS modified asphalt for 42s at 187 ℃ and at a rotating speed of 100r/min to obtain a mixture through wet mixing;

the processing method of the direct-throwing rubber powder comprises the following steps: mixing 91.6 parts by weight of 20-40-mesh truck tire rubber powder, 16 parts by weight of vermiculite, 14 parts by weight of calcium oxide, 0.8 part by weight of maleic anhydride, 7 parts by weight of friction powder, 1.8 parts by weight of iron oxide, 2.7 parts by weight of LDPE and 0.8 part by weight of 1010 antioxidant to obtain a mixture B, wherein the mixing temperature is 110 ℃, the rotation speed of a stirring shaft is 280r/min, and the mixing time is 9.3 minutes; and mixing the mixture B with 3.4 parts by weight of aromatic oil, 3.6 parts by weight of furfural extract oil and 5.8 parts by weight of petroleum resin at the temperature of 67 ℃, the rotation speed of a stirring shaft of 190r/min for 5.8 minutes to obtain the direct-vat-set rubber powder.

The scanning electron microscope images of the direct-vat rubber powder and the common rubber powder in the embodiment are shown in fig. 1-2, the surface of the common rubber powder (CR) is relatively flat, the treated direct-vat rubber powder (MCR) in the application is uneven and in a burr state, has a large surface area, is beneficial to activation modification, and has a large binding force with asphalt when being applied to a cementing material.

Selection of mineral aggregate particle size

Through the control of the passing rate of the key sieve pores, the mineral aggregate can reach the characteristics of similar discontinuity and skeleton compaction. Because a part of rubber powder in the direct-throwing dry-method rubber powder/SBS composite modified asphalt mixture can not be converted into composite modified asphalt and is used as filler to be mixed with fine aggregate, the design gradation of the mixture is not suitable for being fine, and 4 different gradations are designed in 4 areas of fine, medium, coarse and extra-coarse areas. The design void ratio of the mixture is 4.0%, 4 grades are from thin to thick, the oil-stone ratio is increased from small, and the positions of the thin sections of the grading curves are from top to bottom. The determination of the grading curve segment position depends on the 4.75mm and 2.36mm passing rate, the grading 1 curve segment position should be determined above the grading median value, but the passing rate of the two is not higher than 45% and 35%; the position of the thin section of the grading 2 curve is near the median; the position of the fine section of the grading 3 curve is continuously moved downwards, the passing rates of 4.75mm and 2.36mm are controlled at the middle position of the grading median and the lower limit, and are respectively near 35% and 25%; the position of the fine section of the gradation 4 curve is suitably close to the vicinity of the lower limit of gradation. In order to reduce the powder-to-rubber ratio and prolong the fatigue life, the 0.075mm passing rate of 4 grades is reduced from a middle value of 6.0 percent to 5.0 percent, and finally 4 grades of fine, middle, coarse and extra coarse are determined between the upper grading limit and the lower grading limit, and are shown in a table 1.

TABLE 1 four synthetic grading ranges

The road performances of the four asphalt mixtures in three aspects of high temperature stability, water stability and low temperature stability were tested under the same conditions as the proportions of the direct-fed rubber powder and the modified asphalt described in example 4, the processing conditions, and the like, and only the mineral aggregate gradation was used as a variable, and the results are shown in tables 2 to 4:

rut test results for table 24 grading

	Grading 1	Grading 2	Grading 3	Grading 4	Specification requirements
						Degree of dynamic stability (times/mm)	7987	9573	9750	8218	>2800

TABLE 34 Water stability test results

Grading type	Immersion marshall residual stability S₀(％)	Freeze-thaw cleavage strength ratio TSR (%)
			Grading 1	85.42	77.68
Grading 2	92.42	83.30
			Grading 3	94.47	84.14
Grading 4	86.13	78.76
			Specification requirements (%)	≥85	≥80

TABLE 44 grading trabecula low-temperature bending test results

Tables 2-4 prove that for the direct-vat rubber powder in the application, the performances of the gradation 2 and the gradation 3 are obviously superior to those of the other two gradations, which shows that the gradation 2 and the gradation 3 not only can form a good framework embedding and extruding structure, but also can supplement the increased gaps between coarse aggregates. In addition, the asphalt can be effectively coated on the aggregates, so that the cohesiveness and the internal friction of the asphalt mixture are greatly improved, the asphalt mixture is properly crossed in the proportion of coarse aggregates and fine aggregates, and the overall performance of the mixture is improved. For gradation 1, the proportion of fine aggregates accounts for more than 40%, and the water stability and the high-temperature performance are weaker; 4 grades of gradation are thick partially, the coarse aggregate proportion increases, the internal friction between the aggregates increases, but the space between the building stones increases, fine aggregate and rubber powder are not enough to fill the space of the coarse aggregate, the space must be filled with a large amount of asphalt, the forming process compaction of the mixture with a large asphalt dosage is more difficult, under the condition of the same compaction power, the mixture porosity with a large asphalt dosage is large, thereby the water stability and the low-temperature stability of the mixture are poor, on the other hand, 4 grades of asphalt dosage is large, and the resource waste can be caused. In summary, it is considered herein that, referring to the composite gradation of gradation 2 and gradation 3, the mosaic structure of the asphalt mixture can be stabilized by adjusting the proportion of the coarse aggregate and the fine aggregate to increase the overall stability.

Selection of rubber powder and asphalt

The water stability, high temperature stability and low temperature stability test results for different rubber asphalt mixtures are shown in Table 6.

TABLE 64 rubber asphalt mixture Performance test results

The test result shows that the road performance of the direct-throwing rubber powder and SBS double-modified asphalt mixture is much higher than that of the matrix asphalt, and has obvious advantages compared with SBS modified asphalt or rubber asphalt, especially high-temperature performance.

Influence of different direct-throwing rubber powder on performance of mixture

Taking the mixture obtained in example 4 as an experimental group, in order to prove the reason that each performance of the mixture obtained in example 4 is excellent, a control group is set:

control group 1: the difference from the example 4 is that the direct-vat set rubber powder does not contain calcium oxide and ferric oxide;

control group 2: the difference from the example 4 is that the direct-vat set rubber powder does not contain friction powder, calcium oxide and ferric oxide;

control group 3: the difference from the example 4 is that the direct-vat set rubber powder does not contain vermiculite, calcium oxide and ferric oxide;

control group 4: the difference from the embodiment 4 is that the direct-throwing rubber powder does not contain vermiculite and friction powder;

control group 5: the difference from the example 4 is that the direct-vat set rubber powder does not contain vermiculite, friction powder, calcium oxide and ferric oxide.

The experimental group and the control group were tested for their respective properties, and the test results are shown in table 7.

Table 76 rubber asphalt mixture Performance test results

As can be seen from the data in table 7, the experimental group has a very significant advantage over the control group in terms of water stability, high temperature stability, and low temperature stability. Compared with the control group 5, the control group 5 has certain advantages in various performances compared with the common rubber asphalt, but the effect is far less than that of the experimental group in which vermiculite, friction powder, calcium oxide and iron oxide are added, which shows that the existence of the vermiculite, the friction powder, the calcium oxide and the iron oxide has great promotion effect on the improvement of the performance of the mixture. Further exploring the components playing key roles, comparing the control groups 4 and 5, the direct-fed rubber in the control group 4 contains calcium oxide and iron oxide, but the performances of the modified rubber are not improved, and the residual stability ratio and the high-temperature stability are even reduced. Compared with the control group 5, the control groups 2 and 3 respectively increase vermiculite and friction powder in the direct-throwing rubber, the increase of the vermiculite slightly increases the residual stability ratio, the dynamic stability and the bending strain of the mixture, but the increase is not obvious, and the freeze-thaw splitting ratio is even reduced; the increase of the friction powder slightly improves all the performances of the mixture, but is not obvious. Compared with the control group 5, the control group 1 is added with vermiculite and friction powder, and the combined action of the vermiculite and the friction powder enables all the performances of the mixture to be remarkably increased, but the difference is larger compared with an experimental group, and the performances of the mixture are remarkably improved by adding calcium oxide and iron oxide into the mixture. Through the comparative analysis, it can be seen that in the direct-throwing asphalt of the application, or only one or more of vermiculite, friction powder, calcium oxide and iron oxide is added, the improvement of the performance of the mixture is not particularly remarkable, so that the vermiculite, the friction powder, the calcium oxide and the iron oxide are required to be completely mixed for use, and the performance of the mixture can be obviously improved by the action of the vermiculite, the friction powder, the calcium oxide and the iron oxide with other components in the direct-throwing rubber.

When the automobile brake that goes on the road surface, can improve the temperature on road surface, especially in summer hot afternoon, great to the damage on road surface, add vermiculite in this application, when the road surface temperature risees, vermiculite thermal expansion can reduce heat transfer efficiency, reduces the heat to the inside diffusion in road surface for the whole temperature in road surface risees, and the road surface that the pitch takes place to soften and causes takes place easily that deformation is impaired. Under normal conditions, however, the temperature for vermiculite expansion is high, and the temperature for simple braking may not reach the expansion temperature of vermiculite, and presumably because the friction powder exists, the friction force between the tire and the road surface is increased, the temperature of the road surface is increased during braking, or the expansion temperature of vermiculite can be reduced by the friction powder; on the other hand, calcium oxide and iron oxide play a synergistic role and may react with vermiculite, so that the expansion temperature of the vermiculite is reduced, and the stability of the asphalt pavement is improved.

Example 5:

the base course is laid by uniformly mixing 0.2 cubic meter of cement, 0.8 cubic meter of broken stone, 0.6 cubic meter of medium clean sand and 1.3 cubic meters of water, and the thickness of the base course is 20-30cm, wherein the medium clean sand is sand with the particle size of more than 0.25mm and the mass of particles of more than 50% of the total mass;

the reinforcing layer is laid by laying sand which is soaked in water for 20min on a base layer after the base layer is laid, so that the area ratio of the sand to cement concrete on the surface of the base layer is 1:0.8, and 1/2-2/3 of the sand is positioned in the base layer;

and the surface layer is laid by spraying water to the exposed parts of the base layer and the reinforcing layer in the air after the base layer is hardened to wet the parts with the thickness of 1-2cm on the surface, and then laying the asphalt mixture obtained in the embodiment 4, wherein the thickness of the asphalt mixture is 10-15 cm.

Example 6:

the base course is laid by uniformly mixing cement of 0.5 cubic meter, gravel of 1 cubic meter, medium clean sand of 0.5 cubic meter and water of 1 cubic meter, and the thickness of the base course is 20-30 cm;

the reinforcing layer is laid by laying sand stones which are soaked in water for 50min on a base layer after the base layer is laid, so that the area ratio of the sand stones to the cement concrete on the surface of the base layer is 1:1.2, and 2/3 of the sand stones are positioned in the base layer;

Example 7:

the base course is laid by uniformly mixing cement of 0.3 cubic meter, broken stone of 0.9 cubic meter, medium clean sand of 0.55 cubic meter and water of 1.2 cubic meters, and the thickness of the base course is 20-30 cm;

the reinforcing layer is laid by laying sand which is soaked in water for 35min on a base layer after the base layer is laid, so that the area ratio of the sand to cement concrete on the surface of the base layer is 1:1, and 1/2-2/3 parts of the sand are positioned in the base layer;

In this application in the middle of the basic unit on road surface and top layer set up the back up coat, the back up coat is the building stones that the particle diameter is slightly bigger, the even distribution of building stones is on the basic unit surface, is equivalent to even setting up the gim peg between basic unit and top layer, with the inseparable combination of basic unit and top layer, avoids appearing becoming flexible owing to connect insecure, inseparable between the two. In addition, the reinforcing layer in this application uses the grit, and the outward appearance of grit is more mellow and full, compares in the rubble more can with basic unit and top layer in close contact with, and easy compaction.

Although the invention has been described herein with reference to a number of illustrative embodiments thereof, it should be understood that numerous other modifications and embodiments can be devised by those skilled in the art that will fall within the spirit and scope of the principles of this disclosure. More specifically, various variations and modifications are possible in the component parts and/or arrangements of the subject combination arrangement within the scope of the disclosure, the drawings and the appended claims. In addition to variations and modifications in the component parts and/or arrangements, other uses will also be apparent to those skilled in the art.

Claims

1. A processing method of direct-vat-set rubber powder is characterized by comprising the following steps:

and (3) mixing for the second time: mixing the mixture B with 2-4 parts by weight of aromatic oil, 2-4 parts by weight of furfural extract oil and 5-6 parts by weight of petroleum resin to obtain direct-vat-set rubber powder;

the temperature of the first mixing is 85-115 ℃, the rotating speed of a stirring shaft is 250-300 r/min, and the mixing time is 8-10 minutes; the temperature of the second mixing is 60-70 ℃, the rotating speed of the stirring shaft is 150-200 r/min, and the mixing time is 5-6 minutes.

2. An asphalt mixture with the direct vat set rubber powder of claim 1, characterized in that: comprises 0.2-0.3 weight part of directly-thrown rubber powder, 4-5 weight parts of asphalt and 90-95 weight parts of mineral aggregate.

3. The asphalt mixture according to claim 2, wherein the mineral aggregate passes through 100%, 91% to 92%, 69% to 71%, 33.4% to 39.5%, 26% to 27%, 18.5% to 19%, 12% to 13%, 8.3% to 8.6%, 6.5% to 7% and 4.9% to 5.1% in mass percentage, i.e., gradation, when sieved through sieves with mesh openings of 16mm, 13.2mm, 9.5mm, 4.75mm, 2.36mm, 1.18mm, 0.60mm, 0.30mm, 0.15mm and 0.075mm, respectively.

4. A processing method of the asphalt mixture according to any one of claims 2 to 3, characterized in that the direct-throwing rubber powder is firstly dry-mixed with mineral aggregate to obtain a mixture A, and then the mixture A is wet-mixed with asphalt to obtain a mixture;

the asphalt is SBS modified asphalt, the dry mixing temperature is 180-190 ℃, and the wet mixing temperature is 170-180 ℃.

5. The processing method of the asphalt mixture according to claim 4, characterized in that a roller mixer is used for mixing, the dry mixing time is 5-10 s, and the rotation speed of a stirring shaft is 90-130 r/min; the wet mixing time is 35 to 45s, and the rotating speed of the stirring shaft is 60 to 120 r/min.

6. A pavement, comprising a base layer and a surface layer, characterized in that: the base layer is a cement concrete layer, and the surface layer is formed by the asphalt mixture according to any one of claims 2 to 5;

the upper surface of the base layer is provided with a reinforcing layer, and the reinforcing layer is sand stone with the particle size of 8-13 cm.

7. A method of constructing a pavement according to claim 6, comprising the steps of laying a base layer, laying a reinforcing layer and laying a surface layer, wherein:

the surface layer is laid by spraying water to the exposed parts of the base layer and the reinforcing layer after the base layer is hardened to wet the parts with the thickness of 1-2cm on the surface, and then laying the asphalt mixture according to any one of claims 4-6, wherein the thickness of the asphalt mixture is 10-15 cm.