CN106814181B

CN106814181B - One kind specific surface of aggregate removing recycling bitumen samples method from asphalt

Info

Publication number: CN106814181B
Application number: CN201611165875.2A
Authority: CN
Inventors: 吴建涛; 杨帅; 杨滔; 刘泉
Original assignee: Hohai University HHU
Current assignee: Hohai University HHU
Priority date: 2016-12-16
Filing date: 2016-12-16
Publication date: 2019-04-05
Anticipated expiration: 2036-12-16
Also published as: CN106814181A

Abstract

A method for recovering asphalt samples by peeling off the surface of specific aggregates in asphalt mixtures. The method includes the following steps: taking a part of the raw asphalt mixture aggregate to make a regular spherical aggregate; putting the spherical aggregate into the raw asphalt mixture aggregate, and mixing the asphalt mixture; mixing the mixed asphalt The materials were subjected to SHRP short-term aging and SHRP long-term aging simulations respectively; the asphalt-coated spherical aggregates in the asphalt mixture in the aging stage were found, placed on a silica gel plate and placed in an ultra-low temperature refrigerator for low-temperature freezing; After the surface was peeled off, the bitumen was collected from the silica gel sheet and subjected to subsequent bitumen performance testing. Using the phenomenon that the thermal expansion coefficients of the aggregate and the asphalt after low temperature embrittlement are different, the asphalt membrane is peeled off from the surface of the aggregate. The invention is not only simple to operate, saves energy consumption, but also avoids the influence of the traditional asphalt recovery process on the asphalt performance.

Description

One kind specific surface of aggregate removing recycling bitumen samples method from asphalt

Technical field

The invention belongs to bitumen recovery fields, and in particular to one kind specific surface of aggregate removing recycling from asphalt Bitumen samples method.

Background technique

Ageing of asphalt refers to binder of the pitch as aggregate in asphalt, mixes in heat, constructs and use process In unavoidably by the outside environmental elements such as temperature, illumination, air and precipitation influenced and vehicular load under the action of send out The process of a series of physical chemical change such as raw volatilization, oxidation.Ageing of asphalt causes bituminous texture, property to change, into And Pavement Condition is caused to deteriorate, shorten service life of road surface.Thus ageing of asphalt is to influence the master of durability of asphalt pavement Factor is wanted, is always the hot spot of asphalt roads industry research.In order to which the ageing properties to different pitches are carried out than choosing, people are usual Asphalt accelerated ageing simulation is carried out in laboratory, and recycling is stripped simultaneously to pitch in Aging simulation different phase It is tested for the property.Current bitumen recovery extracting method is mainly Abson method and rotary evaporator method, and the two is in extraction process In can all destroy the original state form of pitch and a degree of secondary aging is generated to pitch.The invention avoids traditional asphalts to return Influence of the skill of knocking off to asphalt performance prevents the secondary aging of pitch, and easy to operate, convenient to carry out.

Summary of the invention

The technical issues of solution: the original of pitch can be destroyed during to bitumen extraction for existing bitumen recovery process Shape form simultaneously leads to the problem of a degree of secondary aging to pitch, and the present invention provides a kind of collection specific from asphalt Expect that sur-face peeling recycles bitumen samples method, can influence to avoid traditional recovery process to asphalt performance, prevent pitch secondary Aging, and it is easy to operate, it is convenient to carry out.

Technical solution: one kind specific surface of aggregate removing recycling bitumen samples method from asphalt, including it is following Step:

Step 1, a part for taking material asphalt mixture to gather materials are made sphere and gather materials；

The sphere is gathered materials and is put into during material asphalt mixture gathers materials, and carried out asphalt and mix and stir by step 2；

Asphalt after mixing and stirring is carried out SHRP short ageing, SHRP long-term ageing simulation by step 3 respectively；

The sphere that pitch is wrapped in the asphalt of ageing step is gathered materials and is found out, is placed in silica gel plate by step 4 It is put into ultra low temperature freezer simultaneously and carries out cryogenic freezing；

Step 5 collects pitch from silica gel plate and carries out subsequent pitch after asphalt membrane is from the removing of sphere surface of aggregate Performance test.

Preferably, the diameter of regular sphere is 10mm in the step 1.

Preferably, ultra low temperature freezer cryogenic freezing temperature is -40 DEG C~-60 DEG C in the step 4.

Preferably, ultra low temperature freezer cryogenic freezing temperature is preferably -40 DEG C in the step 4.

Preferably, the ultra low temperature freezer cryogenic freezing time is 30min~90min in the step 4.

Preferably, the ultra low temperature freezer cryogenic freezing time is 30min in the step 4.

The utility model has the advantages that avoiding the secondary oxidation of pitch in 1, removal process, using the specific form of tailor-made aggregate sphere, just It is found in tracking；

2, sex differernce is shunk using pitch brittleness under low temperature condition and pitch and mineral aggregate, so that pitch is cracked automatically and is shelled with mineral aggregate From；

3, it does not stick at this feature of silica gel plate using pitch, carries out follow-up test convenient for collecting pitch；

4, whole process method is effective, easy to operate, and is able to maintain the original state form of pitch.

Detailed description of the invention

Fig. 1 is extraction process and the asphalt performance test chart that freezing recycles.

Specific embodiment

Embodiment 1

When carrying out bitumen recovery to asphalt, using surface of aggregate specific from asphalt provided by the invention Removing recycling bitumen samples method, specifically includes the following steps:

Step 1, a part for taking material asphalt mixture to gather materials are made the regular sphere that diameter is 10mm and gather materials；

Step 3 carries out SHRP short ageing, SHRP long-term ageing simulation to the asphalt after mixing and stirring respectively；

The sphere that pitch is wrapped in the bituminous mixture aggregate of ageing step is gathered materials and is found out by step 4, and it is flat to be placed in silica gel It is put into ultra low temperature freezer while plate and carries out cryogenic freezing, if sphere gathers materials and wraps up in attached pitch and be not enough, can repeat Frozen-thawed cycled is operated to obtain more bitumen samples；Cryogenic temperature is that value is 40 DEG C of bitumen samples Fraass breaking point or less (about -40 DEG C~-60 DEG C), cryogenic freezing time value between 30min~90min according to bitumen samples peeling conditions.

The asphalt performance of the pitch and extractings that obtain to freezing recycling arrived is as follows through measuring:

Temperature is carried out to sample to the bitumen samples of freezing recycling and extracting and reclaiming respectively based on dynamic shear rheometer to sweep Retouch test, different absorption methods compared and analyzed using complex shear modulus and phase angle as basic index, test it is basic Parameter setting is as follows:

Loading mode is arranged to strain controlling mode, temperature range setting is in 28 DEG C~76 DEG C (6 DEG C of gradients), frequency Rate range is arranged to 10rad/s, and the parameter of testing piece is set as 25mm diameter and 1000 μm of spacing, and strain value is arranged 0.1% (in the viscoelastic range of linearity), obtains following measurement result:

Measurement result:

By experimental result drafting pattern 1, from figure 1 it appears that the mechanical property of the pitch of two methods recycling exists Biggish difference, especially complex shear modulus, the complex shear modulus of freezing sample is significantly lower than in Range of measuring temp The complex shear modulus of extraction process sample, bitumen samples can be caused by further demonstrating the extraction process referred in background of the present invention Secondary aging.

It is bright that above embodiments absolutely prove that traditional method for extracting has with the bitumen samples that method proposed by the present invention obtains Aobvious difference, freezing proposed by the present invention effectively avoid the secondary aging of bitumen samples in extractive process, more really Meet practical asphalt performance.

Claims

1. a method for stripping and recovering asphalt samples from specific aggregate surface in asphalt mixture, is characterized in that, comprises the following steps:

Step 1, take a part of the raw asphalt mixture aggregate to make spherical aggregate with a diameter of 10mm;

In step 2, the spherical aggregate is put into the raw asphalt mixture aggregate, and the asphalt mixture is mixed;

Step 3: Perform SHRP short-term aging and SHRP long-term aging simulations on the mixed asphalt mixture respectively;

Step 4: Find out the asphalt-coated spherical aggregates in the asphalt mixture in the aging stage, place them on a silica gel plate, and put them into an ultra-low temperature refrigerator for low-temperature freezing. The low-temperature freezing temperature is -40°C to -60°C. The low-temperature freezing time 30min～90min;

Step 5: After the asphalt membrane is peeled off from the surface of the spherical aggregate, the asphalt is collected from the silica gel plate and the subsequent asphalt performance test is carried out.

2 . The method for recovering asphalt samples by peeling off the surface of specific aggregates in an asphalt mixture according to claim 1 , wherein in the step 4, the low-temperature freezing temperature of the ultra-low temperature refrigerator is -40° C. 3 .

3 . A method for recovering asphalt samples by peeling off the surface of specific aggregates in an asphalt mixture according to claim 1 , wherein the low-temperature freezing time of the ultra-low temperature refrigerator in the step 4 is 30 min. 4 .