CN205898718U - Disconnected disc structure and pitch low temperature ring crack test instrument are frozen to pitch low temperature ring crack - Google Patents

Abstract

The utility model discloses a disconnected disc structure and pitch low temperature ring crack test instrument are frozen to pitch low temperature ring crack freezes disconnected disc structure and includes base, the ring that expands, has a ring channel in the middle of the base, do not expand the ring closely the cover form an annular accommodation space of placing pitch between the outer wall of the ring that does not expand and the ring channel on the interior rampart of ring channel, be equipped with a cynapse on the outer rampart of ring channel, in pitch heating back pouring -in annular region, the control environment temperature lasts and descends, the shrink of pitch ring, and bloated ring amount of contraction is very little, make the inside temperature stress of production of pitch ring sample, owing to set up the cynapse, with the pitch ring under low temperature cracked point control in cynapse department, and through detecting meeting an emergency of temperature variation value and cynapse department, finally try to achieve the ring crack temperature and the ring crack intensity of pitch ring, be used for pitch low temperature ring crack test instrument with the disc structure, the biggest fracture strain who corresponds in the time of can being similar to the fracture of simulation road surface, establish the relevance with the actual low temperature situation of road surface mixture.

Description

A kind of pitch low temperature ring crack freezes disconnected disc structure and pitch low temperature ring crack test instrument

Technical field

The utility model is related to asphalt performance assessment technique field, and more particularly, to a kind of pitch low temperature ring crack freezes disconnected disk knot Structure and pitch low temperature ring crack test instrument.

Background technology

The cracking of bituminous paving is domestic and international road circle question of common concern, and its harm is to make moisture immerse along crack Inside pavement structure, so that sub-surface and roadbed feel like jelly, pavement structure depression of bearing force, produce under Driving Loading Purt mud, wash away, boundary layer local and comes to nothing, ultimately result in road surface and check crack and pit occur, severely impact the traveling of vehicle Quality, greatly reduces the service life on road surface.

The crack of bituminous paving includes load Crack and non-loaded deformation.The crack being produced by load is in some overload of China Serious high-grade highway runway is often met, now how to control fatigue rupture as core content.And another kind of crack, that is, non- Reflection crack caused by the low-temperature shrink crack of load type and semi-rigid type base but generally existing, has caused suitable pass Note is it is well known that both cracks are closely related with the cracking resistance of pitch and asphalt.In recent years, carry out both at home and abroad More research work, wherein, much studies mainly with asphalt surface course cold cracking for main goal in research.

Take the lead in since the cold shrinkage crack to asphalt surface course carries out systematic investigation and study from Canada's sixties in 20th century, road surface Cracking resistance is always the important research content of international road educational circles with material at low temperature performance indications, in research and application neck over nearly 20 years Domain even more achieves breakthrough progress.Achieved with common recognition: control the cryogenic property of pitch and asphalt, set up phase Close cryogenic property index and feasible value, be the key measure of asphalt surface course cold cracking design.And the anti-low-temperature cracking of bituminous paving Performance depends primarily on the cryogenic tensile characteristic of asphalt binder, and the performance of asphalt binder plays a part particular importance, phase Close document to show, its contribution rate to 90%, therefore the research to asphalt surface course cold cracking should be with pitch cryogenic property index Control based on.

By the analysis to domestic and international pitch low temperature evaluation index, current Conventional cryogenic index is in mechanical mechanism, test Result discrimination and still suffer from certain deficiency with aspects such as the road surface degrees of correlation, a lot of aspects are unreasonable；Shrp index can be relatively The cryogenic property of good evaluation matrix pitch, and modified pitch can not be made with good evaluation, and shrp index adopts Creep properties is being classified it is believed that croop property can substitute destructive characteristics, but research shows the phase of croop property and destructive characteristics Closing property is not fine.At this stage, currently existing low temperature index can not be made comparisons to the cryogenic property of pitch clear and definite table Levy, one more easy intuitively index of necessary proposition is evaluated to asphalt performance.

Utility model content

Technical problem to be solved in the utility model there is provided a kind of disconnected disc structure of pitch ring crack jelly and pitch is low Warm ring crack test instrument.

Technical solution adopted in the utility model is:

A kind of pitch ring crack freezes disconnected disc structure, including base and not swollen annulus, has a cannelure in the middle of described base, Described not swollen annulus closely surrounds on the internal ring wall of described cannelure, shape between the outer wall of described not swollen annulus and described cannelure Become an annular accommodation space, described annular accommodation space is used for placing pitch, and described base is on the external annulus of described cannelure It is provided with a cynapse, described cynapse is the cylindrical cynapse on the external annulus be horizontally placed on described cannelure.

In some specific embodiments, the diameter of described cylindrical cynapse can determine according to formula (i):

$s=h-\frac{(d-r_1)\·h}{h}---\left(i\right)$

In formula, s represents the diameter of described cylinder cynapse, and h represents the height of described cylinder cynapse；r₁Described in expression not The outer shroud radius of swollen annulus；Described h represents the height of described pitch annulus；D determines according to formula (ii):

In formula, α_DripLinear expansion coefficient for pitch；α_necrLinear expansion coefficient for not swollen annulus；δ t is cooling extent；r₁ Outer shroud radius for described not swollen annulus；r₂Outer shroud radius for described pitch annulus；In formula, parameter ε_aBy formula (iii) really Fixed:

ε_a=(α_Drip+m·α_Collection) δ t m ε_Collection(iii)

In formula, δ t is cooling extent；α_DripLinear expansion coefficient for pitch；M is the length ratio gathering materials one-dimensional with pitch；α_Collection For the linear expansion coefficient gathering materials；ε_CollectionFor the strain gathered materials.

In some specific embodiments, the height of described cylindrical cynapse is equal to the outer shroud radius of described cannelure Difference with the outer shroud radius of described not swollen annulus.

In some specific embodiments, the centre of described base is provided with a circular depressed, described circular depressed and institute State cannelure with one heart, the radius of described circular depressed is equal to the internal ring wall radius of described cannelure, the depth of described circular depressed Depth less than described cannelure.

In some specific embodiments, linear expansion coefficient≤5 × 10 of described not swollen annulus and described base^-6mm/ mm/℃.

In some specific embodiments, the material of described not swollen annulus is quartz glass, invar alloy, pottery and steel In any one.

In further preferred embodiment, the material of described not swollen annulus is quartz glass.

In some specific embodiments, the material of described base is steel, any one in iron, aluminium.

In some specific embodiments, the bottom of described cannelure is level.

In some specific embodiments, the width of described not swollen annulus is equal to the depth of described cannelure.

The utility model additionally provides a kind of pitch low temperature ring crack test instrument, freezes disconnected circle including pitch ring crack as above Dish structure, described pitch low temperature ring crack test instrument also includes heat sink, temperature sensor and strain acquirement instrument, described cooling dress Put and there is a closing accommodation space that can accommodate described pitch cryogenic property evaluation structure, described temperature sensor includes phase The temperature sensor connecting and temperature acquisition processor, described temperature sensor freezes disconnected disc structure located at described pitch ring crack On base, described strain acquirement instrument includes the strain transducer being connected and strain acquirement processor, and strain transducer is not located at On the inwall relative with described cynapse of swollen annulus.

The beneficial effects of the utility model are:

The utility model provides a kind of pitch ring crack and freezes disconnected disc structure and include the disconnected disc structure of this pitch ring crack jelly Pitch low temperature ring crack test instrument, described pitch ring crack freezes disconnected disc structure and includes base and not swollen annulus, in the middle of described base There is a cannelure, described not swollen annulus closely surrounds on the internal ring wall of described cannelure, the outer wall of described not swollen annulus and institute State and between cannelure, form an annular accommodation space, described annular accommodation space is used for placing pitch, and described base is in described ring The external annulus of shape groove are provided with a cynapse；Described in pouring into after pitch is heated between not swollen annulus and the external annulus of described cannelure Annular region in, with the continuous decrease of environmental Kuznets Curves temperature, pitch annulus is constantly lowered the temperature contraction, and not swollen annulus is with temperature Amount of contraction is very little, is kept approximately constant, so that producing temperature stress inside pitch ring specimen and continuous with continued down Increase, until when temperature is down to certain value, pitch annulus ruptures, and due to being provided with cynapse on the external annulus of cannelure, makes drip Blue or green annulus cross-sectional area at cynapse is minimum, and suffered by cynapse, stress maximum is it is possible to break pitch annulus at low temperature The point splitting controls at cynapse, realizes selective cleavage, and by the strain at detection temperature changing value and cynapse, finally tries to achieve drip The ring crack temperature of blue or green annulus and ring crack intensity.This pitch low temperature ring crack test instrument, mainly has following advantage: 1) pass through approximately Corresponding maximum breaking strain during simulated roadway fracture, low-temperature condition actual with paving mix is set up and is associated；2) can achieve and determine Point fracture, the cylinder cynapse point on pitch annulus, that is, in stress maximum suffered by pitch, there is (this in controlled fracturing blasting herein Point is corresponding with the fracture of actual road surface), and conventional freeze disconnected test, test previous as indefinite breakaway poing position, this not only improves Effective control to test, also targetedly facilitates the measurement to breaking strength values herein；3) it is directed to different compounds Property and proportion of composing, the size of joint base can simulate calculating, adjust the cross-sectional area of cylindric cynapse, Ke Yiyou Pointedly the dissimilar compound of road pavement carries out cryogenic property test, to accomplish to be more nearly with road surface actual state, this A little any pitch crack resistance at low-temperature evaluation at present all cannot be accomplished；4) test out ring crack temperature t_frac(fracture of pitch annulus) While, also measure corresponding fracture strength σ_frac；5) ring being monitored using described pitch cryogenic property evaluation structure Split temperature, with tsrst breaking temperature, there is preferable correlation, and evaluation method accuracy described in the utility model and repeatability Good.

Brief description

Fig. 1 is the top view of base；

Fig. 2 is a-a cross-sectional view in Fig. 1；

Fig. 3 is the pictorial diagram of unlike material and various sizes of not swollen annulus；

Fig. 4 is the pictorial diagram of various sizes of cynapse；

Fig. 5 freezes disconnected disc structure top view for pitch ring crack；

Fig. 6 is b-b cross-sectional view in Fig. 5；

Fig. 7 is pitch low temperature ring crack test instrument structural representation.

Fig. 8 is bituminous paving model schematic；

Fig. 9 is pavement asphalt mixture check model figure；

Figure 10 is pavement cracking schematic illustration of strain；

Figure 11 is pitch annulus and not swollen annulus force balance schematic diagram；

Figure 12 is strain variation schematic diagram before and after pitch annulus is lowered the temperature with not swollen annulus；

Figure 13 is nonuniform section pitch annulus equivalent schematic；

Figure 14 is the correlation analysis figure of the not swollen annulus gained ring crack temperature of quartz glass and tsrst breaking temperature；

Figure 15 is the correlation analysis figure of the not swollen annulus gained ring crack temperature of invar alloy and tsrst breaking temperature；

Figure 16 is the correlation analysis figure of the not swollen annulus gained ring crack temperature of pottery and tsrst breaking temperature；

Figure 17 is strained for the not swollen annulus material of one kind to vary with temperature curve；

Figure 18 is the corresponding rate of temperature fall of different pitches material and ring crack temperature relation figure.

Description of reference numerals:

1- base；2- cannelure；3- internal ring wall；4- external annulus；5- cynapse；6- is not swollen annulus；7- pitch annulus；8- is circular Depression；9- strain transducer；10- temperature sensor；11- closes accommodation space；12- temperature acquisition processor；13- strain acquirement Processor；14- liquid nitrogen cooling system；15- material height temperature test instrument.

Specific embodiment

The utility model is related to a ring crack and freezes disconnected disc structure and a pitch low temperature ring crack test instrument.A kind of pitch ring Split the disconnected disc structure of jelly, including base 1 and not swollen annulus 6.With reference to Fig. 1, Fig. 1 is the top view of base, tool in the middle of described base 1 There is a cannelure 2, described base 1 is provided with a cynapse 5 on the external annulus 4 of described cannelure 2, with reference to Fig. 2, Fig. 2 is a- in Fig. 1 A cross-sectional view, described cynapse 5 is the cylindrical cynapse being horizontally placed on the external annulus 4 of described cannelure 2.Described bottom The centre of seat 1 is provided with a circular depressed 8, and described circular depressed 8 is concentric with described cannelure 2, radius of described circular depressed 8 etc. In internal ring wall 3 radius of described cannelure 2, the depth of described circular depressed 8 is less than the depth of described cannelure 2.Described not swollen The material of annulus 6 need to vary with temperature and Volume Changes very little, linear expansion coefficient≤5 × 10 of described not swollen annulus 6^-6mm/mm/ ℃.In a preferred embodiment, the material of described not swollen annulus 6 is quartz glass.The material of described base 1 is steel, iron, in aluminium Any one.

With reference to Fig. 3, Fig. 3 a is respectively from left to right and uses the different material of quartz glass, pottery, invar alloy, four kinds of ordinary steel The not swollen annulus that matter makes, Fig. 3 b is the not swollen annulus of various sizes of quartz glass material.

With reference to Fig. 4, Fig. 4 is the pictorial diagram of various sizes of cynapse, and described cynapse 5 includes first end and the second end, described First end is cylindrical, and the cylindrical size of described first end can be adjusted, pointedly to simulate road pavement inhomogeneity Type compound carry out cryogenic property test, can accomplish to be more nearly with road surface actual state, described second end is embedded in institute State in the external annulus 4 of cannelure 2.

With reference to Fig. 5, described not swollen annulus 6 closely surrounds on the internal ring wall 3 of described cannelure 2, outside described not swollen annulus 6 Form an annular accommodation space, described annular accommodation space is used for placing pitch, in test process between wall and described cannelure 2 In, first pitch is heated, then poured into described annular accommodation space, cooling shaping, obtain pitch annulus 7, described temperature Acquisition Instrument includes temperature sensor 10 and temperature acquisition processor 12 two parts, and it is recessed that described temperature sensor 10 is placed in described circle Fall into 8 center, the temperature of described base 1 is regarded as the temperature of described pitch annulus 7, and described temperature sensor 10 is used for Test ring crack freezes the temperature of pitch ring in disconnected disk.The height of described cylindrical cynapse is equal to the outer shroud 4 half of described cannelure 2 The difference of the outer shroud radius of footpath and described not swollen annulus 6.Described strain acquirement instrument includes strain transducer 9 and processes with strain acquirement Device 13 two parts, described strain transducer 9 located at described cynapse 5 relative described in not swollen annulus 6 inwall on, due to described bottom There is described circular depressed 8, so facilitating the setting of described strain transducer 9 in seat 1.

With reference to Fig. 6, the bottom of described cannelure 2 is level.The width of described not swollen annulus 6 is equal to described cannelure 2 Depth.

With reference to Fig. 7, the utility model additionally provides a kind of pitch low temperature ring crack test instrument, including pitch ring as above Split the disconnected disc structure of jelly, described pitch low temperature ring crack test instrument also includes heat sink, temperature sensor and strain acquirement instrument, institute State heat sink and there is a closing accommodation space that can accommodate described pitch cryogenic property evaluation structure, described temperature acquisition Instrument includes the temperature sensor 10 being connected and temperature acquisition processor 12, and described temperature sensor 10 is located at described pitch ring crack Freeze on the base 1 of disconnected disc structure, described strain acquirement instrument includes the strain transducer 9 being connected and strain acquirement processor 13, strain transducer 9 is on the inwall relative with described cynapse 5 of not swollen annulus 6.In the present embodiment, pitch low temperature ring Split test instrument and include pitch ring crack jelly disconnected disc structure, material height temperature test instrument 15, temperature sensor (by temperature sensor 10 With temperature acquisition processor 12 two parts composition, both connect by data wire), strain acquirement instrument (strain transducer 9 and and answer Become Acquisition Processor 13 two parts composition, connected by data wire), liquid nitrogen cooling system 14 5 part composition.Material height temperature Test instrument 15 is provided with single-stage cooling compression set, and material height temperature test instrument 15 has closing accommodation space 11.Liquid nitrogen drops The Main Function of warm system 14 is on the basis of the single stage compress heat sink of material height temperature test instrument 15, takes liquid nitrogen Cooling measure is lowered the temperature further to test strengthening.

The utility model provides a kind of evaluation method of pitch crack resistance at low-temperature, comprises the following steps: s1: take or make Standby base 1 and not swollen annulus 2 (no expansion circle ring, abbreviation necr), described base 1 and described not swollen annulus 2 structures such as above-mentioned ring crack freezes base 1 and described not swollen annulus 2 described in disconnected disc structure, and described not swollen annulus 2 is little with temperature Degree changes and Volume Changes occurs, and the shape of described base 1 can be arbitrary shape, such as rectangle, circle, ellipse etc., excellent Described in the embodiment of choosing, base 1 is generally circular in shape, has a cannelure 2, described not swollen annulus 6 is embedding in the middle of described base 1 Cover on the internal ring wall 3 of described cannelure 2, described base 1 is provided with a cynapse 5 on the external annulus 4 of described cannelure 2, described prominent Touching 5 is the cylindrical cynapse being horizontally placed on the external annulus 4 of described cannelure 2；S2: in the outside of described not swollen annulus 6 The madial wall uniform application lubricant of wall and described cannelure 2, so that pitch will not adhere to not swollen annulus in temperature-fall period, Avoid producing abnormal reading strain, affect test data；S3: heated asphalt, poured into described in not swollen annulus 6 and described annular Annular space between the external annulus 4 of groove 2, cooling shaping, obtain pitch annulus 7；S4: described in relative with described cynapse 5 On the madial wall of not swollen annulus 6, strain transducer 9 is set, base 1 arranges temperature sensor 10, by base 1, not swollen annulus 6 put in the closing accommodation space 11 of material height temperature test instrument 15 together with described pitch annulus 7,0 DEG C of preheating 30min, Then heat sink is controlled to be lowered the temperature with steady rate, rate of temperature fall scope is 1-30 DEG C/h, until described pitch annulus 7 breaks Split, detect and record the instantaneous strain value of temperature value and not swollen annulus 6 position in corresponding cynapse 5；S5: draw what detection obtained Instantaneous strain value varies with temperature curve, and when instantaneous strain value occurs jump, corresponding strain value is not swollen during pitch fracture Annulus in the strain value of cynapse correspondence position, due to pitch annulus and not swollen annulus produce in cooling contraction process mutually crowded Pressure is active force and reaction force, i.e. f_{Not swollen annulus}=f_Drip, by testing parameter ε obtaining_{Strain jump value}With ess-strain formula f=ε e·a_{Sectional area}, f can be obtained_{Not swollen annulus}, obtain final product active force f suffered by pitch annulus_Drip.Then pass through f_Drip=σ_Drip·a_Drip, obtain asphalt material Ring crack intensity σ_Drip, i.e. σ_frac.And the corresponding temperature value that ruptures at this moment is temperature during described pitch annulus 7 fracture, I.e. ring crack temperature t_frac.In a preferred embodiment, cooling rate can be 10 DEG C/h.The linear expansion coefficient of described not swollen annulus 2 ≤5×10^-6mm/mm/℃.The material of described not swollen annulus 2 is any one in quartz glass, invar alloy, pottery and steel.Institute The material stating base is steel, iron, any one in aluminium.

Principle Analysis:

Below the mechanism of ring crack test is analyzed.In process of the test, annular freezes what disconnected disk was tested as ring crack Important composition part, its internal composition is as shown in Figure 5.Inner ring be not swollen annulus (no expansion circle ring, referred to as Necr, linear contractive quotiety very little, generally (0～5) × 10^-6Mm/mm/ DEG C), outer shroud is that (linear contractive quotiety α is typically big for pitch ring In 200 × 10^-6Mm/mm/ DEG C), bi-material α differs larger, about two orders of magnitude.In carrying out test temperature-fall period, Pitch is produced with not swollen annulus temperature influence and shrinks, the length reduction amount being produced in the unit interval by temperature change because of pitch ring Bigger than not swollen annulus, make asphalt material directly all create phase in annulus tangential direction and vertical tangent lines direction with not swollen annulus Mutual squeezing action power, with the continuous decline of temperature, asphalt material constantly shrinks in the presence of stress, when (the drip of pitch ring Green material itself) institute's tension stress reach its fracture tensile strength when, pitch ring fracture (therefore claim ring crack test).

First, road surface virtual condition analysis

The Elasticity designing based on material of this test method and strength failure are theoretical.

With reference to Fig. 8, bituminous paving actual conditions, as shown in figure 8, this figure is bituminous paving model schematic, take one of Fritter asphalt is analyzed, road surface Asphalt Mixture check model figure such as Fig. 9, conventional pavement asphalt mixture by Pitch, gather materials and space composition, gather materials about of the total volume 83～85%, pitch of the total volume 10～12%, voidage Account for 4～5%.

It is assumed that gather materials accounting for the 85% of volume, pitch of the total volume 15%, both volume ratios are 5.7:1, and research first wouldn't Consider the volume in space, the cube grid of upper figured_{Gather materials}=0.9473, d_Pitch=1-d_{Gather materials}=0.0527, gather materials with Than for 18:1, proportionality coefficient m represents the one-dimensional length of pitch, i.e. m=18.

As shown in Figure 10, Figure 10 is pavement cracking schematic illustration of strain, and under the conditions of being in microthermal climate, bituminous paving just starts Low-temperature shrink, and due to the longitudinal effect of contraction in road surface, limit the length change on road surface, add road surface cryogenic conditions lower aprons For elastomer, road surface just occurs in that elastic shrinkage deforms, to balance produced temperature stress with this.

Now, still uncracked road surface meets the strain stress relation formula as shown in formula (1.1):

(α_Drip+m·α_Collection) δ t=ε_{Drip (road surface)}+m·ε_Collection(1.1)

2nd, the lab simulation of evaluation method described in the utility model and mechanical analysis

With reference to Figure 11, Figure 11 is pitch annulus and not swollen annulus force balance schematic diagram, lowers the temperature carrying out laboratory test Cheng Zhong, pitch annulus is produced with not swollen annulus temperature influence and shrinks, because pitch annulus is produced in the unit interval by temperature change Length reduction amount bigger than not swollen annulus, make asphalt material and not swollen annulus directly in annulus tangential direction and vertical tangent lines side To all creating mutual squeezing action power, that is, during this, pitch annulus is always maintained at the equilibrium-like of stress before not yet rupturing State, equilibrium relation as shown in formula (2.1), (2.2) for the satisfaction:

p_Drip=p_necr(2.1)

P ＇_Drip=p ＇_necr(2.2)

In formula, p_DripThe interaction force of tangential direction suffered by pitch annulus；p_necrTangential direction suffered by not swollen annulus Interaction force；P ＇_DripPerpendicular to interaction force, the p ＇ of tangential direction suffered by pitch annulus_necrSuffered by not swollen annulus Interaction force perpendicular to tangential direction.

As shown in Figure 11, in contraction process, pitch annulus contracted length is in the unit interval for pitch annulus and not swollen annulus It is greater than not swollen annulus, and poised state to be kept, need to support by the elastic strain of pitch and not swollen annulus.As Fig. 7 institute Show, Fig. 7 is strain variation schematic diagram before and after pitch annulus is lowered the temperature with not swollen annulus, if described pitch annulus is uniform cross-section, Pitch annulus is met with the strain of not swollen annulus with relational expression as shown in formula (2.3):

(α_Dripα_necr) δ t=ε_{Drip (indoor)}+ε_necr(2.3)

In formula, α_DripLinear expansion coefficient for pitch；α_necrLinear expansion coefficient for not swollen annulus；δ t is cooling extent； ε_{Drip (indoor)}Strain for pitch in test；ε_necrStrain for not swollen annulus.

Indoor ring crack test is carried out simulated roadway freezing crack situation, selects σ_{Drip (indoor)}=σ_{Drip (road surface)}Or ε_{Drip (indoor)}= ε_{Drip (road surface)}, wherein, σ_{Drip (indoor)}For stress, σ suffered by pitch in test_{Drip (road surface)}For stress, ε suffered by pitch in actual road surface_{Drip (indoor)}For examination Test the strain of middle pitch, ε_{Drip (road surface)}For the strain of pitch in actual road surface, that is, be equivalent to this ring crack test instrument and actual road surface one Rise and be placed in same cooling environment, so that the fracture planting pitch together is farthest consistent with pavement behavior.

The utility model is provided with a cynapse on the external annulus of described cannelure, and described cynapse is to be horizontally placed on described ring Cylindrical cynapse on the external annulus of shape groove, by arranging this cynapse so that cross-sectional area at cynapse for the pitch annulus Reduce, because on pitch annulus, pressure (i.e. the direct interaction force with not swollen annulus) keeps constant, so in this cynapse Ess-strain suffered by place's pitch is maximum, so that pitch annulus is fixed on and ruptures herein, realizes selective cleavage, such that it is able to pinpoint Strain value at detection of broken.

The utility model can also pass through to adjust the size of cylinder cynapse, as shown in figure 4, so that internal institute of this pitch annulus The breaking strain of the breaking strain being subject to and the actual compound in road surface keeps approximate consistent.By pitch annulus cross section face at cynapse Long-pending diminishing is equivalent to nonuniform section as shown in fig. 13 that, and position at cynapse is equivalent to pitch annulus cross-sectional area in Figure 13 At minimum, that is, at ad line segment.The a point (strain maximum of points) on nonuniform section pitch annulus is selected as research object, to make It is with pavement strain opening relationships ε_a=ε_{Drip (road surface)}, wherein ε_aFor the strain of a point pitch, ε_{Drip (road surface)}For in actual road surface pitch should Become.

Then under the conditions of nonuniform section, formula (2.3) can be converted into formula (2.4)

(α_Dripα_necr) δ t=ε_{Drip (nonuniform section)}+ε_necr(2.4)

Wherein, ε_{Drip (nonuniform section)}Dependent variable produced by nonuniform section pitch annulus entirety.

Assume that cross-sectional length d in Figure 13 is being continually changing, r₁Outer shroud radius for described not swollen annulus；r₂For described drip The outer shroud radius of blue or green annulus；Angle change value is θ.

Because the material modulus that not swollen annulus selects are very big, the ε of generation_necrVery little, first assumes ε_necr≈0.

As shown in figure 13, so it is considered that under identical cooling situation, constantly adjustment pitch toroid size is to making ε_aMeet ε_a=ε_{Drip (road surface)}While, whole pitch annulus keeps constant because of the overall strain amount produced by temperature change, that is,

In formula: ε₁ForThe internal strain of pitch annulus in angle；

ε₂ForThe internal strain of pitch annulus in angle；

And

${\mathrm{\ϵ}}_2={\mathrm{\ϵ}}_a\·\frac{(d-r_1)\·h}{(r_2-r_1)\·h}={\mathrm{\ϵ}}_a\·\frac{d-r_1}{r_2-r_1}$

Then

In formula: r₁For the outer shroud radius of described not swollen annulus, mm；r₂For the outer shroud radius of described pitch annulus, mm；α_DripFor The linear expansion coefficient of pitch；α_necrFor the linear expansion coefficient of not swollen annulus, mm/mm/ DEG C；α_CollectionFor the linear expansion coefficient gathering materials；δt For cooling extent, DEG C；M is the length ratio gathering materials one-dimensional with pitch；It is known.

By the calculating of formula (2.7), formula (2.6) is simplified, formula (2.6) can be converted into formula (2.8),

Wherein,

Have already mentioned above, while so that pitch annulus is selectively ruptured at a, also make the chi by adjusting cylinder cynapse Very little so that this breaking strain suffered by pitch annulus inside (takes point ε_a) with the breaking strain ε of the actual compound in road surface_{Drip (road surface)}(formula (1.1) shown in) keep approximate consistent, that is, as shown in following formula (2.9).

ε_a=ε_{Drip (road surface)}=(α_Drip+m·α_Collection) δ t m ε_Collection(2.9)

Calculated by simultaneous formula (2.8), formula (2.9), you can obtain formula (ii):

In formula, α_DripLinear expansion coefficient for pitch；α_necrLinear expansion coefficient for not swollen annulus；δ t is cooling extent；r₁ Outer shroud radius for described not swollen annulus；r₂Outer shroud radius for described pitch annulus；In formula, parameter ε_aBy formula (iii) really Fixed:

ε_a=(α_Drip+m·α_Collection) δ t m ε_Collection(iii)

In formula, δ t is cooling extent；α_DripLinear expansion coefficient for pitch；M is the length ratio gathering materials one-dimensional with pitch；α_Collection For the linear expansion coefficient gathering materials；ε_CollectionFor the strain gathered materials.D can be calculated by formula (ii) and formula (iii).To sum up, adopt Evaluation method described in the utility model can be for the type of different compounds and proportion of composing, and the size of joint base can be with mould Intend calculating, adjust the cross-sectional area of cylindric cynapse, targetedly can carry out low temperature by the dissimilar compound of road pavement Performance test, to accomplish to be more nearly with road surface actual state, evaluate all no at present by any pitch crack resistance at low-temperature for this point Method is accomplished.

After obtaining length d, you can obtain the pitch annulus cross-sectional area corresponding to Figure 13 middle conductor ad, then according to this face Used by long-pending determination, the size of cylindric cynapse, can obtain the diameter s of cylindrical cynapse according to formula (i),

$s=h-\frac{(d-r_1)\·h}{h}---\left(i\right)$

In formula, h represents the height of described cylinder cynapse；r₁The outer shroud radius of not swollen annulus described in expression；Described h represents The height of described pitch annulus.In a preferred embodiment, the height h of described cylindrical cynapse is equal to the outer of described cannelure The difference of the outer shroud radius of ring radius and described not swollen annulus.

Tested on the external annulus of cannelure cynapse being arranged on described base, pitch annulus is obtained in ring crack with this Corresponding ring crack temperature t during destruction_fracWith ring crack intensity σ_frac.

Herein using die trial size r₁=30mm, r₂=36mm, linear contractive quotiety calculates assumes α_Drip=200 × 10^-6, α_Collection= 5×10^-6, α_necr=0.5 × 10^-6, by simultaneous formula (2.8), (2.9), d=32.2mm can be tried to achieve.True finally by calculating Fixed cylindric cynapse a size of φ 8mm × 6mm (h).

One supposition: p is made to the loading process on actual road surface_Drip=p_Collection, pitch is equal with the interaction force gathering materials, and this ring Split test and also meet p_Drip=p_necr, that is, the interaction force of pitch and not swollen annulus is equal, then formula (2.10) and (2.11):

σ_Drip·a_Drip=σ_Collection·a_Collection=σ_necr·a_necr(2.10)

I.e. ε_Drip·e_Drip·a_Drip=ε_Collection·e_Collection·a_Collection=ε_necr·e_necr·a_necr(2.11)

In formula, e_DripElastic modelling quantity for pitch；e_CollectionFor the elastic modelling quantity gathering materials；e_necrElastic modelling quantity for not swollen annulus.

Assume to gather materials on road surface the elasticity of generation strain equal with the microstrain of not swollen annulus generation, i.e. ε_necr=m ε_Collection.

By the simultaneous equation, obtain a_necr, i.e. the cross-sectional area of not swollen annulus, corresponding annulus highly obtains test institute The thickness of corresponding not swollen annulus.

By the above not swollen annulus ring thickness a size of 2mm analyzing, finally determining this annular die trial, the chi of cylindric cynapse Very little for φ 8mm × 6mm (h).

In sum, the utility model passes through to detect the strain at the temperature change value of temperature-fall period pitch and cynapse, Can get ring crack strain and the ring crack temperature of pitch annulus eventually, and corresponding maximum when the strain of this ring crack can be ruptured with simulated roadway Breaking strain, can also obtain the fracture strength of corresponding pitch, the actual low-temperature condition with paving mix according to ring crack strain Set up association, realize the evaluation of the crack resistance at low-temperature of paving mix；For different mix type and proportion of composing, can With adjust cynapse axial cross section area with targetedly simulated roadway difference compound cryogenic property test, can accomplish with Road surface actual state is more nearly.

3rd, the contrast of the not swollen annulus ring crack test of different materials:

Prepare base as above and not swollen annulus, in the present embodiment, respectively select quartz glass, invar alloy and Pottery, as the material of not swollen annulus, lubricates in the lateral wall of described not swollen annulus and the madial wall uniform application of described cannelure Agent；From 8 kinds of different pitches, the material according to the not swollen annulus of difference is divided into three groups to be tested, and heated asphalt one is little respectively When, pour in the annular space that base as above and not swollen annulus are formed respectively, cooling shaping, obtain 8 kinds of different pitches The pitch annulus that material obtains, the madial wall of not swollen annulus described in relative with described cynapse arranges strain transducer, Temperature sensor is set at the circular central of base, then the pitch low temperature of pitch annulus, not swollen annulus and base composition is resisted Fragility energy evaluation structure is put in material height temperature test instrument, keeps 30min at 0 DEG C, is then lowered the temperature with the speed of 10 DEG C/h straight To the fracture of pitch annulus, test and record the ring crack temperature of each pitch annulus, ruptured temperature respectively with the tsrst of 8 kinds of asphalt materials Degree carries out correlation analysis, obtains experimental result such as Figure 14, Figure 15 and Figure 16, not swollen annulus pictorial diagram such as Fig. 3 of different materials, The correlation analysis result of the bitumen samples ring crack temperature of three kinds of materials of gained and tsrst breaking temperature respectively.According to Figure 14, figure 15 and Figure 16 analysis result, the evaluation method gained ring crack temperature that the utility model provides and tsrst breaking temperature have relatively Good correlation, and using silica glass material gained correlation preferably, and compare pottery, invar alloy material, quartzy glass The linear expansion coefficient α of glass is minimum, so that asphalt material is ruptured, test error is low.Final contrast determines, override Select to be tested using the not swollen annulus of quartz glass.According to the breaking temperature that obtains of test and strain data, draw strain with Temperature variation curve, such as Figure 17, what when the jump strain value of in figure is bitumen samples fracture, not swollen annulus was born instantaneously should Become, can be obtained by formula (3.1) stress-strain relation,

f_{Not swollen annulus}=ε_{Strain jump value}×e_{Not swollen annulus}×a_{Not swollen annulus}(3.1)

In formula: f_{Not swollen annulus}For suffered temperature action power on fracture moment not swollen annulus, unit is n；

ε_{Strain jump value}It is the jump strain value making not swollen annulus produce because of asphalt material fracture, unit is μ ε；

e_{Not swollen annulus}For the elastic modelling quantity of not swollen annulus, (quartz glass material, takes e=7.5 × 10¹⁰Pa), unit is pa；

a_{Not swollen annulus}Cross-sectional area for not swollen annulus (a=6.0 × 10 in test^-5m²), unit is m².

Due to before testing between bitumen samples and not swollen annulus lubricant smear lubrication, what bitumen samples produced draws Power is equal to not swollen annulus pressure, and both are active force and reaction force, i.e. f_{Not swollen annulus}=f_Drip.Therefore, bitumen samples is disconnected Split stress to be calculated as follows:

In formula: f_DripFor suffered temperature action power on not swollen annulus, unit is n；

a_DripFor cross-sectional area (a=1.2 × 10 in test at asphalt binder sample cynapse^-4m²), unit is m².

σ_DripIt is required ring crack intensity σ_frac, the temperature as ring crack temperature index t of corresponding strain projection_frac.

4th, the ring crack humid test under different pitches difference rate of temperature fall:

Select this five kinds of asphalt materials of 110#+5%sbs, 110#, 90#+5%sbs, 90#, 70# respectively respectively according to difference Cooling rate (1 DEG C/h, 5 DEG C/h, 10 DEG C/h, 20 DEG C/h, 30 DEG C/h) carry out ring crack evaluation described in the utility model, select Quartz glass, as not swollen annulus material, from steel base material, obtains ring crack temperature t_fracAnd its experiment of standard deviation sd Result is as shown in table 1 and Figure 18.By the experimental result of table 1 can be seen that to five kinds of pitches respectively with 1 DEG C/h, 5 DEG C/h, 10 DEG C/ H, 20 DEG C/h, the speed of 30 DEG C/h lowered the temperature, same bitumen 3.6 DEG C of rate of temperature fall maximum temperature difference of difference (90#+5%), minimum 2.1 DEG C of temperature (70#), the difference between the ring crack temperature value measured is less；The standard deviation of 5 kinds of rate of temperature fall is compared, 10 DEG C/ The sd average of the rate of temperature fall of h is relatively small, has preferable test repeatable.

Ring crack humid test result under table 1 different pitches difference rate of temperature fall

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Claims (10)

1. a kind of pitch low temperature ring crack freezes disconnected disc structure it is characterised in that including base and not swollen annulus, in the middle of described base There is a cannelure, described not swollen annulus closely surrounds on the internal ring wall of described cannelure, the outer wall of described not swollen annulus and institute State and between cannelure, form an annular accommodation space, described annular accommodation space is used for placing pitch, and described base is in described ring The external annulus of shape groove are provided with a cynapse, and described cynapse is that the cylindrical on the external annulus be horizontally placed on described cannelure is dashed forward Touch.

2. pitch low temperature ring crack according to claim 1 freezes disconnected disc structure it is characterised in that described cylindrical cynapse Diameter can be determined according to formula (i):

In formula, s represents the diameter of described cylinder cynapse, and h represents the height of described cylinder cynapse；r₁Not swollen circle described in expression The outer shroud radius of ring；Described h represents the height of described pitch annulus；D determines according to formula (ii):

In formula, α_DripLinear expansion coefficient for pitch；α_necrLinear expansion coefficient for not swollen annulus；δ t is cooling extent；r₁For institute State the outer shroud radius of not swollen annulus；r₂Outer shroud radius for described pitch annulus；In formula, parameter ε_aDetermined by formula (iii):

ε_a=(α_Drip+m·α_Collection) δ t m ε_Collection(iii)

In formula, δ t is cooling extent；α_DripLinear expansion coefficient for pitch；M is the length ratio gathering materials one-dimensional with pitch；α_CollectionFor collection The linear expansion coefficient of material；ε_CollectionFor the strain gathered materials.

3. pitch low temperature ring crack according to claim 1 freezes disconnected disc structure it is characterised in that described cylindrical cynapse Height be equal to described cannelure the outer shroud radius of outer shroud radius and described not swollen annulus difference.

4. pitch low temperature ring crack according to claim 1 freezes disconnected disc structure it is characterised in that the centre of described base sets There is a circular depressed, described circular depressed is concentric with described cannelure, the radius of described circular depressed is equal to described cannelure Internal ring wall radius, the depth of described circular depressed is less than the depth of described cannelure.

5. pitch low temperature ring crack according to claim 1 freezes disconnected disc structure it is characterised in that the material of described not swollen annulus Expect for any one in quartz glass, invar alloy, pottery and steel.

6. pitch low temperature ring crack according to claim 5 freezes disconnected disc structure it is characterised in that the material of described not swollen annulus Expect for quartz glass.

7. pitch low temperature ring crack according to claim 1 freezes disconnected disc structure it is characterised in that the material of described base is Any one in steel, iron, aluminium.

8. pitch low temperature ring crack according to claim 1 freezes disconnected disc structure it is characterised in that the bottom of described cannelure For level.

9. pitch low temperature ring crack according to claim 1 freezes disconnected disc structure it is characterised in that the width of described not swollen annulus Degree is equal to the depth of described cannelure.

10. a kind of pitch low temperature ring crack test instrument is it is characterised in that the pitch including as described in any one of claim 1-9 is low Warm ring crack freezes disconnected disc structure, and described pitch low temperature ring crack test instrument also includes heat sink, temperature sensor and strain acquirement Instrument, described heat sink has a closing accommodation space that can accommodate described pitch cryogenic property evaluation structure, described temperature Degree Acquisition Instrument includes temperature sensor and the temperature acquisition processor being connected, and described temperature sensor is located at described pitch ring crack Freeze on the base of disconnected disc structure, described strain acquirement instrument includes the strain transducer being connected and strain acquirement processor, should Become sensor on the inwall relative with described cynapse of not swollen annulus.