CN112408864B - Regenerated asphalt mixture and preparation method thereof - Google Patents

Abstract

The invention relates to the technical field of regenerated asphalt, and particularly discloses a regenerated asphalt mixture and a preparation method thereof, wherein the regenerated asphalt mixture comprises 55-75 parts by weight of new aggregate, 25-45 parts by weight of old asphalt mixture, 1-3 parts by weight of mineral powder, 4-7 parts by weight of new asphalt and 0.08-0.56 part by weight of asphalt regenerant; the asphalt regenerant comprises, by weight, 100 parts of a softener, 1-5 parts of an elastomer polymer, 15-30 parts of a linearized active rubber, 0.5-5 parts of a surfactant and 0.5-5 parts of an anti-stripping agent. By adopting the technical scheme in the patent, the old asphalt mixture can be added in a larger proportion, and the performance of the pavement asphalt mixture can be still met, so that the problems of insufficient pavement compaction and low-temperature easy embrittlement in the prior art can be avoided.

Description

Recycled asphalt mixture and preparation method thereof

Technical Field

The invention relates to the technical field of recycled asphalt, in particular to a recycled asphalt mixture and a preparation method thereof.

Background

The road asphalt is affected by wheel load and natural factors, and after a period of service, the properties of asphalt and aggregate in the road asphalt mixture can be changed physically and chemically, and finally the asphalt viscosity in the asphalt mixture is increased, the asphalt is aged and the aggregate is refined. After the asphalt is acted by natural factors in the pavement, the asphalt components can move, namely, the asphalt is correspondingly increased, so that the asphalt is aged and the viscosity is increased, the performance of the asphalt is reduced, and finally the pavement diseases are generated.

The recycling of road asphalt and asphalt mixture is to mix old asphalt mixture milled from road surface with regenerant, new asphalt, new aggregate and so on according to a certain proportion to form recycled asphalt mixture, while old asphalt mixture added in current recycled asphalt mixture should not exceed 25% for example, because beyond this proportion, the recycled asphalt mixture has the problems of insufficient road surface compactness (large porosity) and easy brittle fracture at low temperature, and at present, I find through tests that these problems can be overcome by improving the regenerant.

Disclosure of Invention

The invention provides a recycled asphalt mixture and a preparation method thereof, which aim to solve the problem that the performance of the prior art is reduced when the addition proportion of an old asphalt mixture is higher.

In order to achieve the purpose, the technical scheme of the invention is as follows:

the recycled asphalt mixture comprises, by weight, 55-75 parts of new aggregates, 25-45 parts of old asphalt mixture, 1-3 parts of mineral powder, 4-7 parts of new asphalt and 0.08-0.56 part of asphalt regenerant;

the asphalt regenerant comprises, by weight, 100 parts of a softener, 1-5 parts of an elastomer polymer, 15-30 parts of a linearized active rubber, 0.5-5 parts of a surfactant and 0.5-5 parts of an anti-stripping agent, wherein the linearized active rubber has the characteristics of a high molecular polymer and a small molecular weight organic adhesive.

The technical principle and the effect of the technical scheme are as follows:

the addition of a proper amount of surfactant in the scheme can effectively reduce the surface energy between the old asphalt mixture and the new aggregate, reduce the compaction temperature, improve the compaction degree and further improve the water damage resistance of the asphalt mixture.

In the scheme, the linear active rubber in the asphalt regenerant has the characteristics of part of high molecular polymers and the characteristics of part of organic adhesives (components with smaller molecular weights); the asphalt and the elastomer polymer act together to improve the cohesive force between the old material and the new material, improve the wrapping cohesive force between the new asphalt and the old material and obviously improve the high and low temperature performance of the regenerated asphalt mixture; the aggregate and the anti-stripping agent jointly act on the surface coating property of the asphalt, the new aggregate and the old aggregate, so that the anti-stripping property of the asphalt and the aggregate can be effectively improved, and the water damage resistance of the mixture is further improved.

Due to the advantages, the old materials can be added in a larger proportion, and the performance of the pavement asphalt mixture is not affected.

Further, the new aggregate is graded basalt or limestone stone.

Further, the new asphalt is base asphalt, SBS modified asphalt or rubber asphalt.

Further, the softener is one of soybean oil, dioctyl phthalate, naphthenic oil, trillium oil or rich aromatic hydrocarbon.

Further, the elastomeric polymer is one of SBS, SBR, SIS or butadiene rubber.

Further, the surfactant is one of sodium dodecyl sulfate, glyceryl stearate, polyoxyethylene alkylamine or long-chain fatty alcohol-polyoxyethylene ether. The surfactant is an organic surfactant, is one of warm mixing agents, acts on the asphalt mixture, can reduce the mixing and compacting temperature, and realizes the effect of warm mixing.

Further, the anti-stripping agent is one of p-aminobenzamide, m-aminobenzylamine, a silane coupling agent or sodium lignosulfonate.

The application also discloses a preparation method of the asphalt regenerant, which comprises the following steps:

s1: heating the softening agent to 160 ℃ of 130-;

s2: adding the elastomer polymer according to the proportion, and stirring for 15-45min at the temperature of 140-; then shearing for 10-30min by adopting a high-speed shearing emulsifying machine, wherein the shearing rate is 5000-; then stirring for 30-90min under heat preservation;

s3: adding the surfactant and the anti-stripping agent in proportion, and stirring for 30-60min at the temperature of 140-.

The application also discloses a preparation method of the recycled asphalt mixture, which comprises the following steps:

s1: uniformly mixing the new asphalt and the asphalt regenerant according to the proportion for later use;

s2: putting the old asphalt mixture into a drying drum according to the grading design, drying and heating to 100-140 ℃; putting the new aggregate into another drying roller according to the grading proportion, drying and heating to 160-180 ℃;

s3: mixing the new aggregate and the old asphalt mixture in proportion, dry-mixing for 30s, adding the mixture of the new asphalt and the asphalt regenerant in proportion, continuously mixing for 60s, and maintaining the temperature at 160-180 ℃;

s4: and putting the mineral powder into the mixture of the S3, and continuously blending for 30S to prepare the regenerated asphalt mixture.

Drawings

FIG. 1 is a partial cross-sectional view of a special stirring apparatus in example 10 of the present invention;

fig. 2 is a sectional view taken along the line a-a in fig. 1.

Reference numerals in the drawings of the specification include: the stirring shaft 10, the stirring blades 11, the connecting rod 12, the sliding hole 13, the elastic membrane 14, the shaft sleeve 15, the pull rod 16, the elastic piece 17, the interception plate 18 and the through hole 19.

Detailed Description

The following is further detailed by way of specific embodiments:

example 1:

the recycled asphalt mixture comprises 65 parts of new aggregate, 35 parts of old asphalt mixture, 2 parts of mineral powder, 5 parts of new asphalt and 1.05 parts of asphalt regenerant, wherein the new aggregate is graded basalt or limestone stone; the old asphalt mixture is a graded old asphalt mixture; the new asphalt is matrix asphalt, SBS modified asphalt or rubber asphalt.

The asphalt regenerant comprises, by weight, 100 parts of a softener, 1-5 parts of an elastomer polymer, 15-30 parts of a linearized active rubber (RR), 0.5-5 parts of a surfactant and 0.5-5 parts of an anti-stripping agent; wherein the softener is one of soybean oil, dioctyl phthalate, naphthenic oil, trilinear oil or rich aromatic hydrocarbon; the elastomer polymer is one of SBS, SBR, SIS or butadiene rubber; the surfactant is one of sodium dodecyl sulfate, glyceryl stearate, polyoxyethylene alkylamine or long-chain fatty alcohol-polyoxyethylene ether; the anti-stripping agent is one of p-aminobenzamide, m-aminobenzylamine, a silane coupling agent or sodium lignosulfonate.

The linearized active rubber (RR) can be prepared by the following three methods:

the method comprises the following steps: reference is made to patent application No.: 201711122422.6 discloses a method for preparing linearized active rubber from waste rubber.

The method 2 comprises the following steps: by the twin-screw method, reference is made to patent application numbers: 201210069417.4 discloses a method for continuously preparing liquid reclaimed rubber by a screw extruder.

The method 3 comprises the following steps: adopts a high-temperature boiling method, and refers to the patent application numbers as follows: 200710057975.8A "A paste regenerated rubber and its preparation method".

The linearized active rubber prepared by the three methods has the characteristics of a high molecular polymer and the characteristics of a small molecular weight organic adhesive.

The preparation method of the asphalt regenerant comprises the following steps:

s1: heating the softening agent to 160 ℃ for 130 plus materials, metering and adding the linearized active rubber, and stirring for 60-120min at the temperature of 160 ℃ for 130 plus materials and at the stirring speed of 800 rpm.

S2: adding the elastomer polymer according to the proportion, and stirring for 15-45min at the temperature of 140-; then shearing for 10-30min by adopting a high-speed shearing emulsifying machine, wherein the shearing rate is 5000-; then stirring for 30-90min under heat preservation.

S3: adding the surfactant and the anti-stripping agent in proportion, and stirring for 30-60min at the temperature of 140-.

For the convenience of test, the asphalt recycling agent is divided into 13 groups according to the component content, and the groups are respectively numbered from #1 to #13, and the component content of each number is shown in the following table 1.

Table 1 is a composition Table of asphalt recycling agent Nos. #1 to #13

The asphalt recycling agents obtained from numbers #1 to #13 are used for performance test, and the test method and the standard are as follows: JTG/T5521-2019, test results are shown in Table 2.

Table 2 shows the results of the performance tests on the asphalt recycling agent Nos. #1 to #13

The preparation method of the recycled asphalt mixture comprises the following steps:

s1: and uniformly mixing the new asphalt and the asphalt regenerant with the number being #1 according to the proportion for later use.

S2: putting the old asphalt mixture into a drying drum according to the grading design, drying and heating to 100-140 ℃; adding the new aggregate into another drying roller according to the grading proportion, drying and heating to 160-180 ℃.

S3: mixing the new aggregate and the old asphalt mixture in proportion, dry-mixing for 30s, adding the mixture of the new asphalt and the asphalt regenerant in proportion, continuously mixing for 60s, and maintaining the temperature at 160-180 ℃.

S4: and putting the mineral powder into the mixture of the S3, and continuously blending for 30S to prepare the regenerated asphalt mixture.

Examples 2 to 12 and comparative examples 1 to 4:

the difference from example 1 is that the contents of the components are different from the numbers of the asphalt recycling agents used, as shown in Table 3 below.

Table 3 is a list of the components of examples 1 to 12 and comparative examples 1 to 4

	Novel aggregate	Old asphalt mixture	Mineral powder	Novel asphalt	Asphalt regenerant
						Example 1	65	35	2	5	1.05#1
Example 2	65	35	2	5	1.05#2
						Example 3	65	35	2	5	1.05#3
Example 4	65	35	2	5	1.05#4
						Example 5	65	35	2	5	1.05#5
Example 6	65	35	2	5	1.05#6
						Example 7	65	35	2	5	1.05#7
Example 8	65	35	2	5	1.05#8
						Example 9	65	35	2	5	1.05#9
Example 10	75	25	1	7	0.75#1
						Example 11	55	45	3	4	1.35#1
Example 12	55	45	2	6	2.25#1
						Comparative example 1	65	35	2	5	1.05#10
Comparative example 2	65	35	2	5	1.05#11
						Comparative example 3	65	35	2	5	1.05#12
Comparative example 4	65	35	2	5	1.05#13

Example 13:

the difference from example 1 is that: step S3 of the asphalt recycling agent and step S3 of the recycled asphalt mixture both use a special stirring device, as shown in fig. 1 and fig. 2, the special stirring device includes a horizontally fixed stirring drum, the left end of the stirring drum is provided with an inlet, the right end of the stirring drum is provided with an outlet, a stirring shaft 10 is rotationally connected in the stirring drum, wherein the stirring shaft 10 is arranged in a hollow manner, two ends of the stirring shaft 10 are both connected with a pipeline through a rotary joint, a plurality of stirring blades 11 are fixed on the stirring shaft 10, a heating medium (gas, water, liquid metal and the like) flows through the stirring shaft 10 through the pipeline, thereby heating the stirring shaft 10 and the stirring blades 11, and a driving mechanism for driving the stirring shaft 10 to rotate is further provided.

There is connecting rod 12 along sliding connection in (mixing) shaft 10, connecting rod 12 and (mixing) shaft 10 are coaxial to be set up, set up a plurality of slide opening 13 that are located between stirring vane 11 on the outer wall of (mixing) shaft 10, it has elastic membrane 14 that is located slide opening 13 department to bond on the (mixing) shaft 10 outer wall, PDMS membrane that can be able to bear 200 ℃ high temperature is selected for use to elastic membrane 14 in this embodiment, be equipped with a plurality of moving mechanism on the connecting rod 12, moving mechanism is including fixing axle sleeve 15 on connecting rod 12, be fixed with a plurality of pull rods 16 on axle sleeve 15, a plurality of pull rods 16 are along axle sleeve 15's circumference equipartition, fixed elastic component 17 at the free end of pull rod 16, elastic component 17 is located slide opening 13, and with elastic membrane 14 fixed connection, elastic component 17 can select for use the spring or have elastic gluey post in this embodiment.

A plurality of through holes 19 are formed in the interception plate 18, the through holes 19 are irregularly distributed on the interception plate 18, and the through holes 19 on the interception plate 18 in each moving mechanism do not completely coincide along the axial projection of the stirring shaft 10, so that when a heating medium passes through the stirring shaft 10, the heating medium enters the slide hole 13, the elastic membrane 14 is deformed outwards, and meanwhile, when the heating medium passes through the interception plate 18, an impact force is given to the interception plate 18, so that the interception plate 18 moves in the flow direction, the elastic member 17 is driven to generate a force towards the outside of the slide hole 13, the elastic membrane 14 is deformed inwards, so that the elastic membrane 14 is in a continuously convex and concave state in the stirring process, and asphalt near the stirring shaft 10 moves outwards and is not attached to the stirring shaft 10 all the time, preventing the asphalt from aging.

And (3) carrying out performance test on the regenerated asphalt mixtures obtained in the examples 1-13 and the comparative examples 1-4, wherein the test method and the standard are as follows: JTG F40-2004 technical Specification for Highway asphalt pavement construction, the test results are shown in Table 4.

Table 4 shows the results of the performance tests of examples 1 to 13 and comparative examples 1 to 4

From the test results of table 4 above, it can be derived:

the linear active rubber in the asphalt recycling agent has the characteristics of partial high molecular polymer and partial organic adhesive (components with smaller molecular weight); the asphalt and the elastomer polymer act together to improve the cohesive force between the old material and the new material, improve the wrapping cohesive force between the new asphalt and the old material and obviously improve the high and low temperature performance of the regenerated asphalt mixture; the aggregate and the anti-stripping agent jointly act on the surface coating property of the asphalt, the new aggregate and the old aggregate, so that the anti-stripping property of the asphalt and the aggregate can be effectively improved, and the water damage resistance of the mixture is further improved.

The foregoing is merely an example of the present invention and common general knowledge of the known specific materials and characteristics thereof has not been described herein in any greater extent. It should be noted that, for those skilled in the art, without departing from the present invention, several changes and modifications can be made, which should also be regarded as the protection scope of the present invention, and these will not affect the effect of the implementation of the present invention and the practicability of the patent. The scope of the claims of the present application shall be determined by the contents of the claims, and the description of the embodiments and the like in the specification shall be used to explain the contents of the claims.

Claims (8)

1. The recycled asphalt mixture is characterized in that: the asphalt recycling agent comprises, by weight, 55-75 parts of new aggregates, 25-45 parts of old asphalt mixtures, 1-3 parts of mineral powder, 4-7 parts of new asphalt and 0.08-0.56 part of asphalt recycling agent;

the asphalt regenerant comprises, by weight, 100 parts of a softener, 1-5 parts of an elastomer polymer, 15-30 parts of a linearized active rubber, 0.5-5 parts of a surfactant and 0.5-5 parts of an anti-stripping agent, wherein the linearized active rubber has the characteristics of a high molecular polymer and a small molecular weight organic adhesive;

the softener is one of soybean oil, dioctyl phthalate, naphthenic oil, trilinear oil or rich aromatic hydrocarbon.

2. The reclaimed asphalt mixture according to claim 1, wherein: the new aggregate is graded basalt or limestone stone.

3. The reclaimed asphalt mixture according to claim 1, wherein: the new asphalt is matrix asphalt, SBS modified asphalt or rubber asphalt.

4. The reclaimed asphalt mixture according to claim 1, wherein: the elastomeric polymer is one of SBS, SBR, SIS or butadiene rubber.

5. The reclaimed asphalt mixture according to claim 1, wherein: the surfactant is one of sodium dodecyl sulfonate, glyceryl stearate, polyoxyethylene alkylamine or long-chain fatty alcohol polyoxyethylene ether.

6. The reclaimed asphalt mixture according to claim 1, wherein: the anti-stripping agent is one of p-aminobenzamide, m-aminobenzylamine, a silane coupling agent or sodium lignosulfonate.

7. The reclaimed asphalt mixture according to claim 1, wherein: the preparation method of the asphalt regenerant comprises the following steps:

s1: heating the softening agent to 160 ℃ of 130-;

s2: adding the elastomer polymer according to the proportion, and stirring for 15-45min at the temperature of 140-; then shearing for 10-30min by adopting a high-speed shearing emulsifying machine, wherein the shearing rate is 5000-; then stirring for 30-90min under heat preservation;

s3: adding the surfactant and the anti-stripping agent in proportion, and stirring for 30-60min at the temperature of 140-.

8. The method for preparing the reclaimed asphalt mixture according to any one of claims 1 to 7, wherein the method comprises the following steps: the method comprises the following steps:

s1: uniformly mixing the new asphalt and the asphalt regenerant according to the proportion for later use;

s2: putting the old asphalt mixture into a drying drum according to the grading design, drying and heating to 100-140 ℃; putting the new aggregate into another drying roller according to the grading proportion, drying and heating to 160-180 ℃;

s3: mixing the new aggregate and the old asphalt mixture in proportion, dry-mixing for 30s, adding the mixture of the new asphalt and the asphalt regenerant in proportion, continuously mixing for 60s, and maintaining the temperature at 160-180 ℃;

s4: and putting the mineral powder into the mixture of the S3, and continuously blending for 30S to prepare the regenerated asphalt mixture.

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