CN103575752B - A kind of evaluating asphalt mixture homogeneity - Google Patents

Abstract

The invention discloses a kind of evaluating asphalt mixture homogeneity, first shaping in indoor or the on-site sampling of the method provides the cylinder specimen of the asphalt needed for analysis, then the cross-sectional image of bitumen mixture specimen is gathered by Industrial CT Machine or digital camera, when using the latter, bitumen mixture specimen needs the cutting of first jagsaw teeth cutter; Again image is converted into the black white image of BMP form.Analyze this black white image, obtain each in asphalt cross-sectional image gathering materials and the information of hole, as girth, area, equivalent diameter, major axis minor axis coordinate, centroid position coordinate etc.Finally just to gather materials in compound and the position distribution of hole, distributed number, major axis orientation angle three aspects that distribute calculate respectively and compound cross section gather materials and the distribution of hole, evaluate mixture uniformity whereby.The present invention is based on Digital image technology, the homogeneity directly for asphalt carries out quantitative evaluation, compares additive method, and evaluation result is more accurate.

Description

A kind of evaluating asphalt mixture homogeneity

Technical field

The invention belongs to field of road, particularly relate to a kind of method for quantitatively evaluating of Homogeneity of Asphalt Mixture.

Background technology

The degree of uniformity of asphalt is directly connected to mechanical property and the serviceable life of bituminous pavement.Potentially cause in the factor of hot-mixed bitumen pavement early damage many, the most seriously unevenness of asphalt.The grating of gathering materials in uneven asphalt and (or) bitumen content do not conform to the requirement in initial on-the-spot match ratio, cause the density of compound and voidage to alter a great deal.Research shows: when asphalt is uneven, and the stiffness of compound, pulling strengrth and fatigue lifetime decline, and the service life on road surface reduces, thus accelerates the earlier period damage on road surface.

Asphalt is gathered materials by pitch, thickness, adjuvant and space four-component form.The unevenness of asphalt is the concentrated expression of constituent unevenness in asphalt.People are not used as the homogeneity of asphalt as a serious problem and treat traditionally, and not adopting rigid measures is controlled, conscientious just passable when just requiring construction.And along with the increase of the volume of traffic, homogeneity has become one of principal element determining pavement quality, should attention is thoroughly aroused to.To ascribe road surface voidage to excessive for the main cause damaged by road surface early water, and to ascribe compactness to inadequate by excessive for voidage again, and compacting is not enough, and this is the excessive main cause of early stage road surface voidage really, but solves than being easier to; In fact, the unevenness of asphalt is not only another main cause causing local porosity excessive, and is more insoluble technical matters.Once unevenness appears in asphalt, all effort about design of material all become has made a futile effort.The deficiency of compactness of pavement, is also that compound unevenness causes sometimes, only detects the mean pressure solidity on road surface, often can not reflect problem objectively, also should consider its variability.When the uneven generation of asphalt, only rely on and improve compactness and be difficult to reach the object reducing voidage, even can cause aggregate crusher and real that it is anti-.

Search existing achievement in research and documents and materials, regrettably, at present, it is not also a lot of for determining quantifier elimination to Homogeneity of Asphalt Mixture both at home and abroad.Study carefully its reason, except above-mentioned traditional understanding, following 3 aspect factors may be also had: the research of (1) Homogeneity of Asphalt Mixture is a complicated problem, it to relate to face very wide, systematically research is got up more difficult.(2) be confined to traditional research method, quantitative examination Homogeneity of Asphalt Mixture is very difficult.(3) although, a lot of country progressively recognizes the importance of Homogeneity of Asphalt Mixture in the world at present, but in some countries of high latitude, as Britain, Belgium, Holland, France etc., when Asphalt Mixture Design, custom adopts thinner gathering materials and continuous grading (except SMA), and nominal maximum particle diameter is not more than 20mm, the heterogeneity of asphalt is not subject matter in these countries, therefore not too high to the enthusiasm of mixture uniformity expansion research.

At present, in limited Homogeneity of Asphalt Mixture quantitative examination, the selection of its Evaluation for Uniformity index parameter with determine inadequate science, consider comprehensive not, representativeness is strong, and result has deviation, partly can only reflect the actual conditions of Homogeneity of Asphalt Mixture.

Summary of the invention

In order to overcome the limitation of existing evaluation method, the invention provides a kind of evaluating asphalt mixture homogeneity.

The present invention solves the scheme that its problem adopts: a kind of evaluating asphalt mixture homogeneity, and the method is specially: indoor shaping or on-site sampling provides the cylinder specimen of the asphalt needed for analysis; Gathered the cross-sectional image of bitumen mixture specimen by Industrial CT Machine or digital camera, when using the latter, bitumen mixture specimen needs the cutting of first jagsaw teeth cutter; Image is converted into the black white image of BMP form.Analyze this black white image, obtain each in asphalt cross-sectional image gathering materials and the information of hole, as girth, area, equivalent diameter, major axis minor axis coordinate, centroid position coordinate etc.Obtain on above-mentioned compound cross section gather materials and hole information after, just to gather materials in compound and the position distribution of hole, distributed number, major axis orientation angle three aspects that distribute calculate respectively and compound cross section gather materials and the distribution of hole, evaluate mixture uniformity whereby.

The invention has the beneficial effects as follows: the present invention is based on Digital image technology, the homogeneity directly for asphalt carries out quantitative evaluation, compares additive method, and evaluation result is more accurate.

Accompanying drawing explanation

Fig. 1 is that the present invention divides asphalt horizontal section schematic diagram;

Fig. 2 is that the present invention divides asphalt vertical section schematic diagram.

Embodiment

Evaluating asphalt mixture homogeneity of the present invention, is specially: indoor shaping or on-site sampling provides the cylinder specimen of the asphalt needed for analysis; Gathered the cross-sectional image of bitumen mixture specimen by Industrial CT Machine or digital camera, when using the latter, bitumen mixture specimen needs the cutting of first jagsaw teeth cutter; Image is converted into the black white image of BMP form.Analyze this black white image, obtain each in asphalt cross-sectional image gathering materials and the information of hole, as girth, area, equivalent diameter, major axis minor axis coordinate, centroid position coordinate etc.Obtain on above-mentioned compound cross section gather materials and hole information after, just to gather materials in compound and the position distribution of hole, distributed number, major axis orientation angle three aspects that distribute calculate respectively and compound cross section gather materials and the distribution of hole, evaluate mixture uniformity whereby.

The range deviation rate at the center of gravity that the position distribution state that on cross section, each shelves gather materials is gathered materials by this grade and this cross section geometric center is weighed.Described computing formula is as follows:

The range deviation of center of gravity of gathering materials and geometric center:

Range deviation S is converted to nondimensional r:r _i=S _i/ R

In formula: be respectively i-th grade of barycentric coordinates of gathering materials, i is the size of mesh (square hole screen) of gathering materials;

x _in, y _inbe respectively i-th grade gather materials in the center-of-mass coordinate position of the n-th particle; N _iit is the sum of i-th grade of middle particle that gathers materials; S _ifor the range deviation of center of gravity that on cross section, i-th grade is gathered materials and geometric center; x _pC, y _pCfor horizontal ordinate and the ordinate of the geometric center in cross section; r _ifor the range deviation rate of center of gravity that on cross section, i-th grade is gathered materials and geometric center; R is the distance of geometric center to section edges.

Cross section symmetry is divided into quartern region, adds up these shelves of each region respectively and to gather materials number, utilize following formula to calculate each shelves respectively and to gather materials the number distribution situation in each region:

(5) if N _1i=N _3i, N _2i=N _4i, then

$t_i=\frac{|N_{1i}-N_{2i}|}{N_i},$ N _1i≠0，N _2i≠0

$t_i=[1+\mathrm{\λ}(N_{1i}+N_{2i})]\frac{|N_{1i}-N_{2i}|}{N_i},$ N _1i=0 or N _2i=0

(6) if N _1i≠ N _3i, N _2i≠ N _4i, then

$t_i=c\·\frac{|N_{1i}-N_{3i}|+|N_{2i}-N_{4i}|}{N_i},$

Work as N _1i=N _3i=0 or N _2i=N _4iwhen=0,

In other situations, c=1.

In formula: N _1i, N _2i, N _3i, N _4ibe respectively i-th grade of distributed quantity gathered materials in four pieces of regions; t _ibe i-th grade of distributed number condition parameter of gathering materials in four pieces of regions; λ is undetermined coefficient, generally gets 0.1; N _iit is the sum of i-th grade of middle particle that gathers materials.

On computing nodes, in four regions, each gear gathers materials the average at major axis orientation angle respectively, represents these shelves of this region to gather materials azimuthal principal direction with this, and the position relationship calculating adjacent and opposed area principal direction to gather materials major axis orientation angle distribution as evaluation.Azimuthal distribution of gathering materials state is good, then principal direction symmetry of gathering materials in the vertical and opposed area of principal direction of cross section gathering materials in adjacent area.Be divided into two kinds of situations, described computing formula is as follows:

(5) if N _i>0, then

For one, three regions:

9) if $\stackrel{\‾}{a_{1i}}-\stackrel{\‾}{a_{3i}}>\frac{\mathrm{\π}}{2},S_{13i}=\frac{\mathrm{\π}-(\stackrel{\‾}{a_{1i}}-\stackrel{\‾}{a_{3i}})}{\mathrm{\π}/2};$

10) if $0\&le;\stackrel{\&OverBar;}{a_{1i}}-\stackrel{\&OverBar;}{a_{3i}}<\frac{\mathrm{\&pi;}}{2},S_{13i}=\frac{\stackrel{\&OverBar;}{a_{1i}}-\stackrel{\&OverBar;}{a_{3i}}}{\mathrm{\&pi;}/2};$

11) if $-\frac{\mathrm{\&pi;}}{2}<\stackrel{\&OverBar;}{a_{1i}}-\stackrel{\&OverBar;}{a_{3i}}<0,S_{13i}=\frac{\stackrel{\&OverBar;}{a_{3i}}-\stackrel{\&OverBar;}{a_{1i}}}{\mathrm{\&pi;}/2}$

12) if $\stackrel{\&OverBar;}{a_{1i}}-\stackrel{\&OverBar;}{a_{3i}}<-\frac{\mathrm{\&pi;}}{2},S_{13i}=\frac{\mathrm{\&pi;}+(\stackrel{\&OverBar;}{a_{1i}}-\stackrel{\&OverBar;}{a_{3i}})}{\mathrm{\&pi;}/2}$

For two, four regions:

9) if $\stackrel{\&OverBar;}{a_{2i}}-\stackrel{\&OverBar;}{a_{4i}}>\frac{\mathrm{\&pi;}}{2},S_{24i}=\frac{\mathrm{\&pi;}-(\stackrel{\&OverBar;}{a_{2i}}-\stackrel{\&OverBar;}{a_{4i}})}{\mathrm{\&pi;}/2};$

10) if $0\&le;\stackrel{\&OverBar;}{a_{2i}}-\stackrel{\&OverBar;}{a_{4i}}<\frac{\mathrm{\&pi;}}{2},S_{24i}=\frac{\stackrel{\&OverBar;}{a_{2i}}-\stackrel{\&OverBar;}{a_{4i}}}{\mathrm{\&pi;}/2};$

11) if $-\frac{\mathrm{\&pi;}}{2}<\stackrel{\&OverBar;}{a_{2i}}-\stackrel{\&OverBar;}{a_{4i}}<0,S_{24i}=\frac{\stackrel{\&OverBar;}{a_{4i}}-\stackrel{\&OverBar;}{a_{2i}}}{\mathrm{\&pi;}/2}$

12) if $\stackrel{\&OverBar;}{a_{2i}}-\stackrel{\&OverBar;}{a_{4i}}<-\frac{\mathrm{\&pi;}}{2},S_{24i}=\frac{\mathrm{\&pi;}+(\stackrel{\&OverBar;}{a_{2i}}-\stackrel{\&OverBar;}{a_{4i}})}{\mathrm{\&pi;}/2}$

For one, two regions:

9) if $\stackrel{\&OverBar;}{a_{1i}}-\stackrel{\&OverBar;}{a_{2i}}>\frac{\mathrm{\&pi;}}{2},S_{12i}=\frac{(\stackrel{\&OverBar;}{a_{1i}}-\stackrel{\&OverBar;}{a_{2i}})-\mathrm{\&pi;}/2}{\mathrm{\&pi;}/2};$

10) if $0\&le;\stackrel{\&OverBar;}{a_{1i}}-\stackrel{\&OverBar;}{a_{2i}}<\frac{\mathrm{\&pi;}}{2},S_{12i}=\frac{\mathrm{\&pi;}/2-(\stackrel{\&OverBar;}{a_{1i}}-\stackrel{\&OverBar;}{a_{2i}})}{\mathrm{\&pi;}/2};$

11) if $-\frac{\mathrm{\&pi;}}{2}<\stackrel{\&OverBar;}{a_{1i}}-\stackrel{\&OverBar;}{a_{2i}}<0,S_{12i}=\frac{\mathrm{\&pi;}/2+(\stackrel{\&OverBar;}{a_{1i}}-\stackrel{\&OverBar;}{a_{2i}})}{\mathrm{\&pi;}/2}$

12) if $\stackrel{\&OverBar;}{a_{1i}}-\stackrel{\&OverBar;}{a_{2i}}<-\frac{\mathrm{\&pi;}}{2},S_{12i}=\frac{-\mathrm{\&pi;}/2-(\stackrel{\&OverBar;}{a_{1i}}-\stackrel{\&OverBar;}{a_{2i}})}{\mathrm{\&pi;}/2}$

S _i=S _13i+S _24i+S _12i

(6) if N _i=0, S _i=0;

In formula: be respectively i-th grade of azimuthal average gathered materials in four pieces of regions, i.e. azimuthal principal direction, s _1i, S _2i, S _3i, S _4ibe respectively i-th grade of position angle summation of gathering materials in four pieces of regions; N _1i, N _2i, N _3i, N _4ibe respectively i-th grade of distributed quantity gathered materials in four pieces of regions; S _13i, S _24i, S _12ibeing respectively i-th grade gathers materials in one, three regions, the evaluation number of two, four regions and the distribution of one, two zone aspect angles; S _iit is the evaluation index of i-th grade of azimuthal distribution of gathering materials.

The distribution index that cross section gathers materials is:

d _a=η×∑ki×(ri+ti+si)

In formula: d _afor distribution index of gathering materials in asphalt; η is a undetermined coefficient relevant to aggregate grading; k _ifor the area ratio that on cross section, i-th grade is gathered materials; r _ifor the range deviation rate of center of gravity that on cross section, i-th grade is gathered materials and geometric center; t _ibe i-th grade of distributed number condition parameter of gathering materials in four pieces of regions; s _iit is the evaluation number of i-th grade of azimuthal distribution of gathering materials.

Be similar to the computing method of distribution of gathering materials, on cross section, the position distribution state of all kinds of hole is weighed by the center of gravity of such hole and the range deviation rate at this cross section geometric center.Described computing formula is as follows:

The range deviation of hole center of gravity and geometric center:

Range deviation S ' is converted to nondimensional r ': r ' _i=S ' _i/ R

In formula: S ' _ifor the center of gravity of the i-th class hole on cross section and the range deviation of geometric center; be respectively the barycentric coordinates of the i-th class hole, x ' _in, y ' _inbe respectively the center-of-mass coordinate position of the n-th particle in the i-th class hole; N ' _iit is the sum of particle in the i-th class hole; x _pC, y _pCfor the geometric center position coordinates in cross section; R ' _ifor the center of gravity of the i-th class hole on cross section and the range deviation rate of geometric center; R is the distance of geometric center to section edges.K _i' be the area ratio of the i-th class hole on cross section, k ' _i=a ' _i/ a '; A ' _ifor the total area of the i-th class hole on cross section; A ' is the total area of hole all kinds of on cross section;

Cross section symmetry is divided into quartern region, adds up such number of apertures of each region respectively, utilize following formula to calculate the number distribution situation of all kinds of hole in each region respectively:

(7) if N ' _1i=N ' _3i, N ' _2i=N ' _4i, then

$t_i^{\text{'}}=\frac{|N_{1i}^{\text{'}}-N_{2i}^{\text{'}}|}{N_i^{\text{'}}},$ N′ _1i≠0，N′ _2i≠0

$t_i^{\text{'}}=[1+{\mathrm{\&lambda;}}^{\text{'}}\&CenterDot;(N_{1i}^{\text{'}}+N_{2i}^i)]\frac{|N_{1i}^{\text{'}}-N_{2i}^{\text{'}}|}{N_i^{\text{'}}},$ N ' _1i=0 or N ' _2i=0

(8) if N ' _1i≠ N ' _3ior N ' _2i≠ N ' _4i, then

$t_i^{\text{'}}=c\&CenterDot;\frac{|N_{1i}^{\text{'}}-N_{3i}^{\text{'}}|+|N_{2i}^{\text{'}}-N_{4i}^{\text{'}}|}{N_i^{\text{'}}}$

As N ' _1i=N ' _3i=0 or N ' _2i=N ' _4iwhen=0, in other situations, c '=1.

In formula: N ' _1i, N ' _2i, N ' _3i, N ' _4ibe respectively the distributed quantity of the i-th class hole in four pieces of regions; T ' _ibe the distributed number condition parameter of the i-th class hole in four pieces of regions; λ ' is undetermined coefficient, generally gets 0.1; N ' _ithe same.

Respectively the average at each gear hole major axis orientation angle in four regions on computing nodes, represents the azimuthal principal direction of such hole of this region with this, calculates the position relationship of adjacent and opposed area principal direction as evaluation hole major axis orientation angle distribution.Hole azimuthal distribution state is good, then vertical the and opposed area inner pore principal direction symmetry of adjacent area inner pore principal direction on cross section.Be divided into two kinds of situations, described computing formula is as follows:

(7) if N ' _i>0, then

For one, three regions:

13) if ${\stackrel{\&OverBar;}{a_{1i}}}^{\text{'}}-{\stackrel{\&OverBar;}{a_{3i}}}^{\text{'}}>\frac{\mathrm{\&pi;}}{2},S_{13i}^{\text{'}}=\frac{\mathrm{\&pi;}-({\stackrel{\&OverBar;}{a_{1i}}}^{\text{'}}-{\stackrel{\&OverBar;}{a_{3i}}}^{\text{'}})}{\mathrm{\&pi;}/2};$

14) if $0\&le;{\stackrel{\&OverBar;}{a_{1i}}}^{\text{'}}-{\stackrel{\&OverBar;}{a_{3i}}}^{\text{'}}<\frac{\mathrm{\&pi;}}{2},S_{13i}^{\text{'}}=\frac{{\stackrel{\&OverBar;}{a_{1i}}}^{\text{'}}-{\stackrel{\&OverBar;}{a_{3i}}}^{\text{'}}}{\mathrm{\&pi;}/2};$

15) if $-\frac{\mathrm{\&pi;}}{2}<{\stackrel{\&OverBar;}{a_{1i}}}^{\text{'}}-{\stackrel{\&OverBar;}{a_{3i}}}^{\text{'}}<0,S_{13i}^{\text{'}}=\frac{{\stackrel{\&OverBar;}{a_{3i}}}^{\text{'}}-{\stackrel{\&OverBar;}{a_{1i}}}^{\text{'}}}{\mathrm{\&pi;}/2}$

16) if ${\stackrel{\&OverBar;}{a_{1i}}}^{\text{'}}-{\stackrel{\&OverBar;}{a_{3i}}}^{\text{'}}<-\frac{\mathrm{\&pi;}}{2},S_{13i}^{\text{'}}=\frac{\mathrm{\&pi;}+({\stackrel{\&OverBar;}{a_{1i}}}^{\text{'}}-{\stackrel{\&OverBar;}{a_{3i}}}^{\text{'}})}{\mathrm{\&pi;}/2}$

For two, four regions:

13) if ${\stackrel{\&OverBar;}{a_{2i}}}^{\text{'}}-{\stackrel{\&OverBar;}{a_{4i}}}^{\text{'}}>\frac{\mathrm{\&pi;}}{2},S_{24i}^{\text{'}}=\frac{\mathrm{\&pi;}-({\stackrel{\&OverBar;}{a_{2i}}}^{\text{'}}-{\stackrel{\&OverBar;}{a_{4i}}}^{\text{'}})}{\mathrm{\&pi;}/2};$

14) if $0\&le;{\stackrel{\&OverBar;}{a_{2i}}}^{\text{'}}-{\stackrel{\&OverBar;}{a_{4i}}}^{\text{'}}<\frac{\mathrm{\&pi;}}{2},S_{24i}^{\text{'}}=\frac{{\stackrel{\&OverBar;}{a_{2i}}}^{\text{'}}-{\stackrel{\&OverBar;}{a_{4i}}}^{\text{'}}}{\mathrm{\&pi;}/2};$

15) if $-\frac{\mathrm{\&pi;}}{2}<{\stackrel{\&OverBar;}{a_{2i}}}^{\text{'}}-{\stackrel{\&OverBar;}{a_{4i}}}^{\text{'}}<0,S_{24i}^{\text{'}}=\frac{{\stackrel{\&OverBar;}{a_{2i}}}^{\text{'}}-{\stackrel{\&OverBar;}{a_{4i}}}^{\text{'}}}{\mathrm{\&pi;}/2}$

16) if ${\stackrel{\&OverBar;}{a_{2i}}}^{\text{'}}-{\stackrel{\&OverBar;}{a_{4i}}}^{\text{'}}<-\frac{\mathrm{\&pi;}}{2},S_{24i}^{\text{'}}=\frac{\mathrm{\&pi;}+({\stackrel{\&OverBar;}{a_{2i}}}^{\text{'}}-{\stackrel{\&OverBar;}{a_{4i}}}^{\text{'}})}{\mathrm{\&pi;}/2}$

For one, two regions:

13) if ${\stackrel{\&OverBar;}{a_{1i}}}^{\text{'}}-{\stackrel{\&OverBar;}{a_{2i}}}^{\text{'}}>\frac{\mathrm{\&pi;}}{2},S_{12i}^{\text{'}}=\frac{({\stackrel{\&OverBar;}{a_{1i}}}^{\text{'}}-{\stackrel{\&OverBar;}{a_{2i}}}^{\text{'}})-\mathrm{\&pi;}/2}{\mathrm{\&pi;}/2};$

14) if $0\&le;{\stackrel{\&OverBar;}{a_{1i}}}^{\&prime;}-{\stackrel{\&OverBar;}{a_{2i}}}^{\&prime;}<\frac{\mathrm{\&pi;}}{2},S_{12i}^{\&prime;}=\frac{\mathrm{\&pi;}/2-({\stackrel{\&OverBar;}{a_{1i}}}^{\&prime;}-{\stackrel{\&OverBar;}{a_{2i}}}^{\&prime;})}{\mathrm{\&pi;}/2};$

15) if $-\frac{\mathrm{\&pi;}}{2}\&le;{\stackrel{\&OverBar;}{a_{1i}}}^{\text{'}}-{\stackrel{\&OverBar;}{a_{2i}}}^{\text{'}}<0,S_{12i}^{\text{'}}=\frac{\mathrm{\&pi;}/2+({\stackrel{\&OverBar;}{a_{1i}}}^{\text{'}}-{\stackrel{\&OverBar;}{a_{2i}}}^{\text{'}})}{\mathrm{\&pi;}/2};$

16) if ${\stackrel{\&OverBar;}{a_{1i}}}^{\&prime;}-<{\stackrel{\&OverBar;}{a_{2i}}}^{\&prime;}<-\frac{\mathrm{\&pi;}}{2},S_{12i}^{\&prime;}=\frac{-\mathrm{\&pi;}/2-({\stackrel{\&OverBar;}{a_{1i}}}^{\&prime;}-{\stackrel{\&OverBar;}{a_{2i}}}^{\&prime;})}{\mathrm{\&pi;}/2};$

S′ _i=S′ _13i+S′ _24i+S′ _12i

(8) if N ' _i=0, S ' _i=0;

In formula: be respectively the azimuthal average of the i-th class hole in four pieces of regions, i.e. azimuthal principal direction, ${\stackrel{\&OverBar;}{a_{1i}}}^{\&prime;}=S_{1i}^{\&prime;}/N_{1i}^{\&prime;},{\stackrel{\&OverBar;}{a_{2i}}}^{\&prime;}=S_{2i}^{\&prime;}/N_{2i}^{\&prime;},{\stackrel{\&OverBar;}{a_{3i}}}^{\&prime;}=S_{3i}^{\&prime;}/N_{3i}^{\&prime;},{\stackrel{\&OverBar;}{a_{4i}}}^{\&prime;}=S_{4i}^{\&prime;}/N_{4i}^{\&prime;},;$ S ' _1i, S ' _2i, S ' _3i, S ' _4ibe respectively the position angle summation of the i-th class hole in four pieces of regions; N ' _1i, N ' _2i, N ' _3i, N ' _4ibe respectively the distributed quantity of the i-th class hole in four pieces of regions; S ' _13i, S ' _24i, S ' _12ibe respectively the i-th class hole in one, three regions, the evaluation number of two, four regions and the distribution of one, two zone aspect angles; S ' _iit is the evaluation index of the i-th class hole azimuthal distribution.

On cross section, the distribution index of hole is:

d _p=η′×∑k′ _i×(r′ _i+t′ _i+S′ _i)

In formula: d _afor asphalt mesoporosity distribution index; η ' is a undetermined coefficient relevant to pore-size; K ' _ifor the area ratio of the i-th class hole on cross section, k _i=a _i/ a; Ai is i-th grade of total area gathered materials on cross section; A is the total area that on cross section, each shelves gather materials; R ' _ifor the center of gravity of the i-th class hole on cross section and the range deviation rate of geometric center; T ' _ibe the distributed number condition parameter of the i-th class hole in four pieces of regions; S ' _iit is the evaluation number of the i-th class hole azimuthal distribution.

On cross section, mixture uniformity index d is:

d=d _a+d _p

Mixture uniformity on this direction is characterized with mixture uniformity in one group of parallel cut.The overall homogeneity of asphalt carries out comprehensive evaluation by compound horizontal direction and vertical direction homogeneity.

Computing formula is as follows:

D=α×d _h+β×d _v

In formula: D is Homogeneity of Asphalt Mixture index; α, β are respectively horizontal direction and vertical direction mixture uniformity to the weight of overall homogeneity; d _h, d _vbe respectively asphalt horizontal direction and vertical direction uniformity index.

d _h=∑γ _h(i-i)×d _h(i-i)

d _v=∑γ _v(i-i)×d _v(i-i)

In formula, γ _{h (i-i)}, γ _{v (i-i)}be respectively level and vertical direction i-th cross section mixture uniformity to the influence coefficient of overall homogeneity; d _{h (i-i)}, d _{v (i-i)}be respectively level and vertical direction i-th cross section mixture uniformity index.

Homogeneity of Asphalt Mixture index D is less, and corresponding Homogeneity of Asphalt Mixture is better; Otherwise then Homogeneity of Asphalt Mixture is poorer.

Claims (1)

1. an evaluating asphalt mixture homogeneity, is characterized in that, the method is specially: indoor shaping or on-site sampling provides the cylinder specimen of the asphalt needed for analysis; Gathered the cross-sectional image of bitumen mixture specimen by Industrial CT Machine or digital camera, when using the latter, bitumen mixture specimen needs the cutting of first jagsaw teeth cutter; Image is converted into the black white image of BMP form; Analyze this black white image, obtain each in asphalt cross-sectional image gathering materials and the information of hole, described in gather materials and the information of hole comprises girth, area, equivalent diameter, major axis minor axis coordinate, centroid position coordinate; Obtain on above-mentioned compound cross section gather materials and hole information after, just to gather materials in compound and the position distribution of hole, distributed number, major axis orientation angle three aspects that distribute calculate respectively and compound cross section gather materials and the distribution of hole, evaluate mixture uniformity whereby;

The range deviation rate at the center of gravity that the position distribution state that on cross section, each shelves gather materials is gathered materials by this grade and this cross section geometric center is weighed; Described computing formula is as follows:

The range deviation of center of gravity of gathering materials and geometric center:

Range deviation S is converted to nondimensional r:r _i=S _i/ R

In formula: be respectively i-th grade of barycentric coordinates of gathering materials, i is the size of mesh of square hole screen;

x _in, y _inbe respectively i-th grade gather materials in the center-of-mass coordinate position of the n-th particle; N _iit is the sum of i-th grade of middle particle that gathers materials; S _ifor the range deviation of center of gravity that on cross section, i-th grade is gathered materials and geometric center; x _pC, y _pCfor horizontal ordinate and the ordinate of the geometric center in cross section; r _ifor the range deviation rate of center of gravity that on cross section, i-th grade is gathered materials and geometric center; R is the distance of geometric center to section edges;

Cross section symmetry is divided into quartern region, adds up these shelves of each region respectively and to gather materials number, utilize following formula to calculate each shelves respectively and to gather materials the number distribution situation in each region:

(1) if N _1i=N _3i, N _2i=N _4i, then

N _1i≠0，N _2i≠0

n _1i=0 or N _2i=0

(2) if N _1i≠ N _3ior N _2i≠ N _4i, then

Work as N _1i=N _3i=0 or N _2i=N _4iwhen=0,

In other situations, c=1;

In formula: N _1i, N _2i, N _3i, N _4ibe respectively i-th grade of distributed quantity gathered materials in four pieces of regions; t _ibe i-th grade of distributed number condition parameter of gathering materials in four pieces of regions; λ is undetermined coefficient, gets 0.1; N _iit is the sum of i-th grade of middle particle that gathers materials;

On computing nodes, in four regions, each shelves gather materials the average at major axis orientation angle respectively, represent these shelves of this region to gather materials azimuthal principal direction with this, and the position relationship calculating adjacent and opposed area principal direction to gather materials major axis orientation angle distribution as evaluation; Azimuthal distribution of gathering materials state is good, then principal direction symmetry of gathering materials in the vertical and opposed area of principal direction of cross section gathering materials in adjacent area; Be divided into two kinds of situations, described computing formula is as follows:

(1) if N _i> 0, then

For one, three regions:

1) if

2) if

3) if

4) if

For two, four regions:

1) if

2) if

3) if

4) if

For one, two regions:

1) if

2) if

3) if

4) if

S _i＝S _13i+S _24i+S _12i

(2) if N _i=0, S _i=0;

In formula: be respectively i-th grade of azimuthal average gathered materials in four pieces of regions, i.e. azimuthal principal direction, s _1i, S _2i, S _3i, S _4ibe respectively i-th grade of position angle summation of gathering materials in four pieces of regions; N _1i, N _2i, N _3i, N _4ibe respectively i-th grade of distributed quantity gathered materials in four pieces of regions; S _13i, S _24i, S _12ibeing respectively i-th grade gathers materials in one, three regions, the evaluation number of two, four regions and the distribution of one, two zone aspect angles; S _iit is the evaluation index of i-th grade of azimuthal distribution of gathering materials;

The distribution index that cross section gathers materials is:

d _a＝η×∑ki×(ri+ti+S _i)

In formula: d _afor distribution index of gathering materials in asphalt; η is a undetermined coefficient relevant to aggregate grading; k _ifor the area ratio k that on cross section, i-th grade is gathered materials _i=a _i/ a, a _ifor the total area that i-th on cross section grade is gathered materials, a is the total area that on cross section, each shelves gather materials; r _ifor the range deviation rate of center of gravity that on cross section, i-th grade is gathered materials and geometric center; t _ibe i-th grade of distributed number condition parameter of gathering materials in four pieces of regions; S _iit is the evaluation index of i-th grade of azimuthal distribution of gathering materials;

Be similar to the computing method of distribution of gathering materials, on cross section, the position distribution state of all kinds of hole is weighed by the center of gravity of such hole and the range deviation rate at this cross section geometric center; Described computing formula is as follows:

The range deviation of hole center of gravity and geometric center:

Range deviation S ' is converted to nondimensional r ': r ' _i=S ' _i/ R

In formula: S ' _ifor the center of gravity of the i-th class hole on cross section and the range deviation of geometric center; be respectively the barycentric coordinates of the i-th class hole, y ' _inbe respectively the center-of-mass coordinate position of the n-th particle in the i-th class hole; N ' _iit is the sum of particle in the i-th class hole; x _pC, y _pCfor the geometric center position coordinates in cross section; R ' _ifor the center of gravity of the i-th class hole on cross section and the range deviation rate of geometric center; R is the distance of geometric center to section edges;

Cross section symmetry is divided into quartern region, adds up such number of apertures of each region respectively, utilize following formula to calculate the number distribution situation of all kinds of hole in each region respectively:

(3) if N ' _1i=N ' _3i, N ' _2i=N ' _4i, then

N′ _1i≠0，N′ _2i≠0

n ' _1i=0 or N ' _2i=0

(4) if N ' _1i≠ N ' _3ior N ' _2i≠ N ' _4i, then

As N ' _1i=N ' _3i=0 or N ' _2i=N ' _4iwhen=0, in other situations, c '=1;

In formula: N ' _1i, N ' _2i, N ' _3i, N ' _4ibe respectively the distributed quantity of the i-th class hole in four pieces of regions; T ' _ibe the distributed number condition parameter of the i-th class hole in four pieces of regions; λ ' is undetermined coefficient, gets 0.1; N ' _ithe same;

Respectively the average at each shelves hole major axis orientation angle in four regions on computing nodes, represents the azimuthal principal direction of such hole of this region with this, calculates the position relationship of adjacent and opposed area principal direction as evaluation hole major axis orientation angle distribution; Hole azimuthal distribution state is good, then vertical the and opposed area inner pore principal direction symmetry of adjacent area inner pore principal direction on cross section; Be divided into two kinds of situations, described computing formula is as follows:

(3) if N ' _i>0, then

For one, three regions:

5) if

6) if

7) if

8) if

For two, four regions:

5) if

6) if

7) if

8) if

For one, two regions:

5) if

6) if

7) if

8) if

S′ _i＝S′ _13i+S′ _24i+S′ _12i

(4) if N ' _i=0, S ' _i=0;

In formula: be respectively the azimuthal average of the i-th class hole in four pieces of regions, i.e. azimuthal principal direction, s ' _1i, S ' _2i, S ' _3i, S ' _4ibe respectively the position angle summation of the i-th class hole in four pieces of regions; N ' _1i, N ' _2i, N ' _3i, N ' _4ibe respectively the distributed quantity of the i-th class hole in four pieces of regions; S ' _13i, S ' _24i, S ' _12ibe respectively the i-th class hole in one, three regions, the evaluation number of two, four regions and the distribution of one, two zone aspect angles; S ' _iit is the evaluation index of the i-th class hole azimuthal distribution;

On cross section, the distribution index of hole is:

d _p＝η′×∑k′ _i×(r′ _i+t′ _i+S′ _i)

In formula: d _pfor asphalt mesoporosity distribution index; η ' is a undetermined coefficient relevant to pore-size; K ' _ifor the area ratio of the i-th class hole on cross section, k ' _i=a ' _i/ a '; A ' _ifor the total area of the i-th class hole on cross section; A ' is the total area of hole all kinds of on cross section; R ' _ifor the center of gravity of the i-th class hole on cross section and the range deviation rate of geometric center; T ' _ibe the distributed number condition parameter of the i-th class hole in four pieces of regions; S ' _iit is the evaluation number of the i-th class hole azimuthal distribution;

On cross section, mixture uniformity index d is:

d＝d _a+d _p

Mixture uniformity on this direction is characterized with mixture uniformity in one group of parallel cut; The overall homogeneity of asphalt carries out comprehensive evaluation by compound horizontal direction and vertical direction homogeneity;

Computing formula is as follows:

D＝α×d _h+β×d _v

In formula: D is Homogeneity of Asphalt Mixture index; α, β are respectively horizontal direction and vertical direction mixture uniformity to the weight of overall homogeneity; d _h, d _vbe respectively asphalt horizontal direction and vertical direction uniformity index;

d _h＝∑γ _h(i-i)×d _h(i-i)

d _v＝∑γ _v(i-i)×d _v(i-i)

In formula, γ _{h (i-i)}, γ _{v (i-i)}be respectively level and vertical direction i-th cross section mixture uniformity to the influence coefficient of overall homogeneity;

D _{h (i-i)}, d _{v (i-i)}be respectively level and vertical direction i-th cross section mixture uniformity index;

Homogeneity of Asphalt Mixture index D is less, and corresponding Homogeneity of Asphalt Mixture is better; Otherwise then Homogeneity of Asphalt Mixture is poorer.