CN101748677B - Cold-regenerated emulsified asphalt mixture and method of cold-regenerated emulsified asphalt mixture for road surface reconstruction - Google Patents
Cold-regenerated emulsified asphalt mixture and method of cold-regenerated emulsified asphalt mixture for road surface reconstruction Download PDFInfo
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Abstract
The invention provides a cold-regenerated emulsified asphalt mixture and a method of the cold-regenerated emulsified asphalt mixture for road surface reconstruction. In the method, the damage condition of a structural layer below a surface layer is measured on the spot, and then quantitative evaluation is carried out on the bearing capacity so as to obtain actual mechanics and structural parameters; the production of the regenerated asphalt mixture is carried out in a cold mixing factory after milling materials on the asphalt surface layer of an old road, cement, emulsified asphalt and water mixed together; the regenerated asphalt mixture passes the forming test piece detection; the mixture obtained by the above steps is used for a to-be-reconstructed road surface structure, including the laying of a roadbed, a base layer and the surface layer. Moreover, the cold-regenerated asphalt mixture used for the above method has the following characteristics: mineral materials which are mainly composed of the milling materials of the asphalt surface layer of the old road, asphalt cementing materials and residual gaps form a multi-phase disperse system structure with a space network structure; the material property is granular; and the mechanics strength is reached by the cohesive force and the inner frictional resistance of the asphalt mixture.
Description
Technical field
The present invention relates to highway construction, especially cold regeneration Emulsified Asphalt Mixture and be used for the method for road surface reconstruction.
Background technology
The reconstruction of semi-rigid asphalt pavement and reparation can produce a large amount of old asphalt pavement materials, consider this part all regeneration of old asphalt pavement material from the protection environment and the aspect that economizes on resources.According to the analysis to regeneration techniques, the cold reproduction ratio of mulseal is fit to this project situation.Because the semi-rigid type base in about 50% highway section does not damage, can be used as basic unit behind the old asphalt pavement material regeneration and use.Though domestic and international many areas still exist Key Issues to need further investigation in the engineering practical application all in the regeneration of testing, research and analyse the old asphalt pavement material.For this reason, the inventor puts into practice according to the speedway alteration work, the reconstruction structural thickness that cold regeneration zone is judged, contained to the availability of former semi-rigid type base determines that the material of the conversion relation of basic unit's modulus and cold regeneration mix compression rebound modulu in the cold regeneration of Research on Structural Modulus combinatory analysis of basic unit in method, the cold regeneration and cold regeneration mix forms design and carried out system research, and then proposition patent application of the present invention.So-called " modulus ", promptly product can be used as the technological parameter of integrated survey index on mechanical index, structure, at different product, determines by mechanical test and experience usually.
The pitch resource of China is relatively poorer, particularly high-quality road asphalt quantity is few especially, can not satisfy the needs of fast-developing expressway construction far away, over surplus causing 10 year, the road asphalt of overwhelming majority speedway has to depend on import, and often making us the thorax order, the height of the price of Imported Asphalt is tongue-tied, in order to reduce investment outlay, accelerate construction speed, have to select thin flexible pavement for use when building speedway, this bitumen layer that has also caused China's asphalt pavement of highway is generally thin a lot of than external.Meanwhile, the transportation of China but develops very fast, and the traffic volume and carload all increase day by day, and the quantity of heavy-duty vehicle increases substantially especially.Can only approach under the situation of bitumen layer by making, in order to adapt to the demand of communications and transportation, build, design, construction each side have only the bearing capacity of basic unit made higher requirement, the higher semi-rigid type base of intensity just becomes the base layer structure that China's asphalt pavement of highway the most generally uses.According to statistics, semi-rigid asphalt pavement is the main road structure type of China's speedway at present, accounts for more than 75% of total kilometrage.This road structure normally is made up of asphalt surface course and semi-rigid type base.China is the speedway semi-rigid asphalt pavement of open to traffic, and its thickness of bituminous surface mostly is 15～16cm, about the thick 20cm of semi-rigid type base.People generally believe that the major advantage of semi-rigid asphalt pavement is for a long time: 1. plate body is strong, bearing capacity is big, flexure is little; 2. reduce investment outlay, can repair more road with less money.But through use for many years, this road surface has also exposed some defective that can not be ignored and deficiencies: the 1. reflection crack of the shrinkage cracking of semi-rigid type base and the asphalt surface course that causes thus; 2. the fatigue damage of semi-rigid type base and since half just the design philosophy of basic unit's flexible pavement be to be based upon basic unit as on the basis of bearing course, the fatigue damage of basic unit just equals the destruction of whole road structure; 3. the intensity of semi-rigid type base, modulus problems of too.These defectives and deficiency and the magnitude of traffic flow increase substantially with overload problems serious, having caused a large amount of design periods is that the asphalt pavement of highway in 15 years was open to traffic about 7～8 years, at most in the time in 10 years, the different check crack of degree, hole groove, rut etc. are early stage to be damaged and must carry out large repairs with regard to having occurred.This road surface is when carrying out large repairs, and asphalt surface course is at first fallen by milling, and the milling of surface layer is with regard to two problems that must solve: one, the decision problem of the following bearing capacity of pavement structure of asphalt surface course, to determine the mode of utilizing of these road surface structare layers; Two, the handling problems of the old asphalt pavement material RAP of Hui Shouing (reclaimed asphalt pavement).Road structure design at present, it no matter is newly-built or reconstruction, all more and more be presented as technology-economic problems,, provided definite method based on the overlay thickness that contains cold regeneration zone of performance so the present invention introduces flexible pavement reconstruction structure design with life cycle cost analysis.
By of the finite element analysis of engineering mathematics method to cold-regenerated road surface structure, take all factors into consideration the influence to maximum stretching strain of basic unit and surface layer maximum shear stress in the maximum compressive strain of roadbed end face, the cold regeneration of basic unit's modulus in the cold regeneration, the ideal range of basic unit's modulus is 3000～4000MPa in the cold regeneration.In conjunction with the laboratory test results of cold recycled asphalt mixture, as long as the modulus of basic unit just can satisfy the performance requirement of structure and material greater than 2200MPa in the cold regeneration.
The bituminous mixture regeneration; be needs to be overhauled or discarded flexible pavement; dig (milling) through turning over); reclaim; broken; screening; with newly gathering materials; new bituminous material suitably cooperates; again mix system; formation has the reclaimed asphalt mixture of requirement pavement performance, is used for the new road surface structare layer of making, and its result of use and new bituminous mixture are quite or approaching; the regeneration of bituminous mixture; can save a large amount of pitch and sandstone material, reduce the cost of building the road, simultaneously; also help the discarded asphalt pavement material of punishment; energy conservation, the protection environment has remarkable economic efficiency and social benefit.
In a word, farthest utilize former road structure and ground surface material that asphalt pavement of highway is carried out large repairs, road usefulness material and Sustainable utilization of resources, reduction maintenance cost both can have been realized, again can be under the prerequisite of environment pollution that as far as possible reduces obsolete material and disposal cost, recover comprehensively or improve the pavement performance on former road surface, realize the harmony of speedway social benefit, economic benefit and environmental benefit.
Summary of the invention
According to above-mentioned present situation, the object of the invention is, a kind of cold regeneration Emulsified Asphalt Mixture is provided and is used for the method that reconstruct on the road surface.
According to method involved in the present invention, at first tackle the damaged condition and the bearing capacity of former road surface semi-rigid type base and following deck and make correct evaluation to determine the mode of utilizing of these road surface structare layers, a kind of new road structure is proposed on this basis, the deficiency of former road structure can be remedied, and early stage damage can be avoided effectively; According to the performance requirement of new road structure, carry out reclaimed asphalt mixture material composition research, and then can utilize the old asphalt pavement material with holding water then.
Adopt following steps:
At first, following deck damaged condition of surface layer and bearing capacity are carried out quantitatively evaluating, obtain actual mechanics and structural parameters by field survey.
To carry out reclaimed asphalt mixture production in cold mixing factory behind old road asphalt surface course milling material, cement, mulseal and the water.
In order to reach suitable cold reengineer performance, in RAP, add an amount of mulseal as regenerated additive.
The compound of above-mentioned steps gained is used to the making that road structure to be reconstructed comprises roadbed, basic unit and surface layer.
Especially, adopt the road structure of the formation of said method, the reclaimed asphalt mixture so that plantmix's regeneration obtains is used for going to a grassroots level of new road surface, goes to a grassroots level to replace plain asphalt; The milling material of old road lime-fly ash aggregate base is added cement, after plantmix's regeneration, be used for the subbase on new road; For the cement stabilized macadam base flexible pavement, old road asphalt surface course and lime-fly ash aggregate base milling material are added cement, plantmix's regeneration, regenerating mixture is used for the subbase on new road surface, to replace the two-ash soil subbase.
The specific embodiment
Order of the present invention provides a kind of cold regeneration Emulsified Asphalt Mixture and is used for the method for road surface reconstruction.
The method according to this invention at first, is carried out quantitatively evaluating to following deck damaged condition of surface layer and bearing capacity, obtains the mechanics parameter modulus of each deck reality.
According to the investigation result of semi-rigid asphalt pavement speedway overhaul engineering, the damaged condition and the disunity of asphalt surface course and the following deck of surface layer.Considerable highway section, the surface layer well damage, but decks such as basic unit, subbase, roadbed but do not have anything to damage, and flexure is also smaller even also little when newly-built, is the sustainable use that realizes road usefulness material resources, and these decks should be reused.For this reason, need to make correct evaluation to the damaged condition and the bearing capacity of these decks, the mode of utilizing again with decision, and determine to provide foundation for new road structure.
Adopt following method, by detecting and calculate the modulus of each road surface structare layer below the surface layer.
(1) asphalt surface course is fallen in milling, utilizes the Beckman beam to measure the flexure of semi-rigid type base end face;
(2) basic unit is fallen in milling, utilizes the point-to-point position with basic unit flexure measuring point of Beckman beam vertically corresponding up and down) flexure of mensuration subbase end face;
(3) break off the base basic unit or dig test pit of milling utilizes the modulus of the point-to-point mensuration roadbed of loaded plate end face;
(4), directly measure the thickness at basic unit and subbase flexure measuring point place at the section of milling;
(6) according to the flexure, modulus and the thickness that measure, the value of poisson's ratio parameter is gone out the modulus (detection computations of other road surface structare layer modulus can be carried out in view of the above) of subbase, basic unit by finite element analysis (principle, mode aftermentioned) software inverse.
The damaged pavement behavior that said method is suitable for:
(1) semi-rigid type base of spacing more than or equal to the 3m crack occur, the average of its modulus, variance are not all damaged the equal substantially of basic unit with having, and illustrate that the damage of these types does not have influence on the bearing capacity of semi-rigid type base, can continue to utilize.
Though spacing is more than or equal to the not influence of bearing capacity to semi-rigid type base of the crack of 3m, but these crack reflections can become the passage that water enters basic unit to the reflection crack that asphalt surface course forms, and then cause the damage by water of basic unit bad, therefore the type reflection crack being carried out caulking joint timely, is to prolong the flexible pavement effective means in application life.
(2) modulus of semi-rigid type base reduces with the reduction of fracture interval, and spacing will have influence on the modulus of semi-rigid type base smaller or equal to the crack of 2m, should excavate heavily shop.When the piece that lumpiness 30cm occurs when semi-rigid type base split, its modulus (average) had been more or less the same with the modulus of pellet class graded broken stone subbase.
(3) average of roadbed and graded broken stone subbase modulus and variance are all very approaching, illustrate that these decks have all reached more stable state.
By subgrade modulus, subbase flexure and thickness, basic unit's flexure and the thickness that point-to-point detection draws, adopt finite element software to go out the modulus of subbase and basic unit by inverse, the result shows:
(1) semi-rigid asphalt pavement is through for many years use, damaging can appear in semi-rigid type base, it mainly is the crack, its modulus reduces with the reduction of fracture interval, spacing is more than or equal to the not influence of modulus to semi-rigid type base of the crack of 3m, and spacing can make the modulus of semi-rigid type base decay smaller or equal to the crack of 2m.
(2) through for many years use, though dissimilar damages can appear in semi-rigid type base, but the modulus average (variance) of the roadbed below the semi-rigid type base that is damaged, pellet class subbase all differs very little, and the modulus average (variance) of all corresponding with do not have damaging semi-rigid type base roadbed, pellet class subbase is approaching on the numerical value, explanation is under the effect of natural subsidence and vehicular load, the deck of roadbed and pellet class can reach stable status, can continue to utilize.
According to cold-regenerated road surface structure of the present invention, in conjunction with long-life flexible pavement design concept, the scope of surface layer top thickness 15cm is high stressed district, should adopt high-quality bituminous mixture, and this part bituminous mixture also must play anti-rut, antiskid, effect that anti-damage by water is bad.For this reason, should select for use pavement performance preferably heat mix new bituminous mixture (it is poor that the pavement performance specific heat of cold recycled asphalt mixture is mixed new bituminous mixture), and thickness must be greater than 15cm.
The gross thickness of basic unit and new black top surface layer is that 28cm (quite newly-built 25cm) has surpassed 20cm in the cold regeneration, reached the thickness requirement of long-life flexible pavement, design concept according to the long-life flexible pavement, the damage on road surface mainly is positioned at the top 10cm scope of surface layer, and last, the middle surface layer on new black top road surface have all adopted pavement performance modified asphalt concrete preferably for this reason.
The basic principle of road structure limited element analysis technique and method:
Use the analysis of finite element method flexible pavement first since nineteen sixty-eight Duncan, this method is used for road structure and material existing decades of history.Usually, think that Finite Element Method is a kind of numerical method that approaches initial boundary value problem.This method is divided into some simple subdomains (finite element) separating the territory, with these subdomains an entity problem (or infinite dimension problem) is changed into finite dimensional problem, solves the approximate solution that this finite dimensional problem obtains practical problem then.In short, the solution approach of Finite Element Method is as follows:
The first step: the geometry territory is divided into simple subdomain, just " unit " how much.There is man-to-man projection relation between the discretization of finite element and the true territory.
Second step: in each unit, insert that some key points---node illustrates geometrical property.
The 3rd step: by estimating the corresponding state variable of every bit in node insertion shift value, corner value.If what describe geometrical property and state variable is identical node and insertion function, so this unit is called " waiting the ginseng unit ".This insertion will produce two important results: one is that infinite dimensional problem is reduced to finite dimensional problem, and another is to replace separating of partial differential with separating of Algebraic Equation set.
The 4th step: get in touch all points with whole Algebraic Equation set.So just produced matrix equation, matrix equation connects the input of unit specified point (node) and the output of identical point.In order in bigger territory, to solve an equation, to put together a node of the normal node of the matrix equation of less subdomain and obtain whole matrix equation.
Because the progress of Finite Element maximum is its applicability to extensive problem, Any shape, any material property, any load mode can both be simulated, and this method has obtained general utilization in traditional ramification problem.At present, more researcher tends to use large-scale finite element program to carry out test pavement simulating, and these softwares comprise ANSYS, ABAQUS etc., and the present invention also adopts the structural performance of ANSYS software analysis cold-regenerated road surface.
When carrying out the flexible pavement mechanics property analysis, road structure generally will be reduced to desirable mechanical model, as: 1. elastic half-space body; 2. Elastic Layered System; 3. viscoplasticity stratiform system; 4. the plate on the elastic foundation; 5. the plate on the Elastic Layered System.Most studies thinks, when research flexible pavement method for designing, comparatively desirable mechanical model is the multilayer elastic layered system, adopts linear structure modulus among the ANSYS to analyze the structural performance on cold recycled asphalt road surface for this reason.
In ANSYS, the relation of linear structure has following definition:
{σ}＝[D]{ε
el}
In the formula:
{ σ }=stress vector=[σ
xσ
yσ
zσ
Xyσ
Yzσ
Xz];
{ ε
El}=elastic strain vector={ ε }-{ ε
Th}
[D]=elastic matrix.The inverse matrix of matrix D can be write as
Wherein:
E
xYoung's modulus of elasticity for the x direction;
V
XyPoisson's ratio for the xy plane;
G
XyModulus of shearing for the xy plane.
Result of calculation is analyzed
(1) the maximum compressive strain of roadbed end face is all less than 280 μ ε, and reduces with the increase of cold regeneration zone modulus (compressive strength), and when cold regeneration zone modulus during greater than 2000MPa, the trend that the maximum compressive strain of roadbed end face reduces becomes slower.
(2) the maximum stretching strain of basic unit reduces with the increase of cold regeneration zone modulus in the cold regeneration, its lapse rate also diminishes gradually with the increase of cold regeneration zone modulus, when cold regeneration zone modulus during greater than 3000MPa, the maximum stretching strain of this deck is smaller (less than 28 μ ε), at this moment merely the modulus by increasing cold regeneration zone to its maximum stretching strain to reduce effect not obvious, modulus increases 1000MPa, and maximum stretching strain at most also just reduces several μ ε.
(3) maximum shear stress of asphalt surface course is with the increase of cold regeneration zone modulus, shows to reduce the trend that afterwards increases earlier.The road structure of the modulus 4500～7000MPa of basic unit, when cold regeneration zone modulus is in 3000～4000MPa, it is 0.226～0.228MPa (shear strength of conventional hot-mix asphalt mixture is easy to meet this requirement) that the maximum shear stress of surface layer reaches minimum, the road structure of the modulus 4000MPa of basic unit, though the maximum shear stress of its surface layer reaches minimum during between 4000～6000MPa in cold regeneration zone modulus, but work as cold regeneration zone modulus in 3000～4000MPa scope, the surface layer magnitude of maximum shearing stress at most also just increases 0.001MPa (0.226MPa).Take all factors into consideration the influence of cold regeneration zone modulus to three indexs of maximum shear stress of the maximum stretching strain of basic unit in the maximum compressive strain of roadbed end face, the cold regeneration and surface layer, it is more satisfactory that the modulus of cold regeneration zone is controlled at 3000～4000MPa.
When cold regeneration zone modulus during at 3000～4000MPa, the maximum stretching strain of basic unit is 60% of the maximum stretching strain of no cold regeneration zone road surface (former road surface) basic unit.
Method by point-to-point detection flexure and modulus, obtained the modulus of each deck of cold-regenerated road surface, with these deck modulus is parameter, the maximum stretching strain of basic unit and three mechanical performance indexs of surface layer maximum shear stress in the maximum compressive strain of the roadbed end face of cold-regenerated road surface structure, the cold regeneration have been carried out finite element analysis, and the result shows:
(1) road structure of different cold regeneration zone modulus, the maximum compressive strain of its roadbed end face is satisfied the technical requirements of long-life flexible pavement all less than 280 μ ε, and along with the increase of cold regeneration zone modulus, the maximum compressive strain meeting of roadbed end face reduces gradually.
(2) the maximum stretching strain of basic unit reduces with the increase of cold regeneration zone modulus in the cold regeneration, when cold regeneration zone modulus during greater than 3000MPa, only by increase cold regeneration zone modulus to its maximum stretching strain to reduce effect not obvious.
(3) maximum shear stress of asphalt surface course is with the increase of cold regeneration zone modulus, shows to reduce the trend that afterwards increases earlier, and when cold regeneration zone modulus was in 3000～4000MPa, the maximum shear stress of surface layer reached minimum value or near minimum value.
(4) take all factors into consideration of the influence of cold regeneration zone modulus to the maximum stretching strain of basic unit and three indexs of surface layer maximum shear stress in the maximum compressive strain of roadbed end face, the cold regeneration, it is more satisfactory that cold regeneration zone modulus is controlled at 3000～4000MPa, simultaneously the maximum stretching strain of semi-rigid type base is reduced, be 60% of former road structure only, and then significantly improved the fatigue life of semi-rigid type base.
According to above preliminary analysis, its concrete job practices is as follows:
Transport old road asphalt surface course and lime-fly ash aggregate base milling material back factory,, carry out reclaimed asphalt mixture production through necessary fragmentation, screening.Comprise adding regenerative agent additive, newly gather materials (as required) central mix.In order to reach suitable cold reengineer performance, described regenerated additive is a mulseal.Use conventional cement stabilized macadam batching plant just can produce.
Said method at road structure to be reconstructed comprise roadbed, basic unit and surface layer.Analyze definite road structure according to multilayer stratiform elastic system theory, it comprises two main design standards, i.e. the compressive strain of stretching strain at the bottom of the bitumen layer and roadbed end face.
According to the present invention, the cold regeneration techniques that adds mulseal comprises:
1. determining of mulseal consumption is based on the processing of three basic conditions consumption with the design mulseal.First kind of situation supposes that RAP is that black gathers materials, and the mulseal of interpolation must wrap up RAP fully; Second kind of situation, the consumption of mulseal should make the pitch among the RAP return to its initial viscosity, and promptly aged asphalt is all softening; The third situation is the combination of preceding two kinds of situations, and promptly the pitch that part is aging takes place to soften, but because the softening degree of old pitch is difficult to quantize, should require to test the consumption of determining mulseal according to the mechanics of cold regeneration mix.Comprise that the optimum emulsification asphalt content should make in Marshall stability and flow valuve, indirect tensile strength, compressive strength, the modulus of resilience one or several reach optimization; Second method is that the optimum emulsification asphalt content of selecting should make the void content of cold regeneration mix 9～12%.
2. add cement to improve the stiffness and the bad ability of anti-damage by water of cold recycled asphalt mixture, addition is generally RAP and 1～2% of the gross mass of newly gathering materials.
3. mixing and stirring of mulseal cold regeneration mix do not need heating, at normal temperatures various composition material uniform mixings got final product.
4. shaping test piece, the cold regeneration mix test specimen must distribute redundant moisture and health to reach corresponding strength, just can the demoulding, the demoulding may damage test specimen too soon, test specimen should be stayed in the compacting mould and is sidelong during health, health is divided into short-term health and two kinds of long-term healths again, simulate the short-term performance and the long-term behaviour of cold regeneration mix respectively, the short-term health is that test specimen is placed on 2～4h under 60 ℃ of environment, long-term health then is to place 24～48h under 60 ℃ of environment, and the density of test specimen should be near the compacted density of on-the-spot compound.
According to the present invention, adopt the road structure of the formation of said method, comprise that with behind old road asphalt surface course milling material, cement, mulseal and the water regenerating mixture that plantmix's regeneration obtains as going to a grassroots level of new road surface, is gone to a grassroots level to replace plain asphalt; The milling material of old road lime-fly ash aggregate base is added cement, the subbase on the new road of conduct after plantmix's regeneration; For the cement stabilized macadam base flexible pavement, old road asphalt surface course and lime-fly ash aggregate base milling material are added cement, plantmix's regeneration, regenerating mixture is as the subbase on new road surface, to replace the two-ash soil subbase.
Further, according to different former road structures, adopt dual mode with the cold regeneration in protobitumen road surface:
1. in conjunction with flexible pavement highway section scheme, behind old road asphalt surface course milling material adding breeze, cement, mulseal and water, plantmix regenerates, and regenerating mixture is used for going to a grassroots level of new road surface, goes to a grassroots level to replace plain asphalt LSM-25; The milling material of old road lime-fly ash aggregate base is added 2% cement, after plantmix's regeneration, be used for the subbase on new road.
2. for the cement stabilized macadam base flexible pavement, old road asphalt surface course and lime-fly ash aggregate base milling material are added 2% cement, plantmix's regeneration, regenerating mixture is used for the subbase on new road surface, to replace the two-ash soil subbase.
The compacting process of basic unit in the cold regeneration
Compacting process for the first time
After cold recycled asphalt mixture paved and finishes, rolling of road roller promptly was the compacting process first time of basic unit in the cold regeneration.Since added cement, after cold recycled asphalt mixture paves and finishes, just must the beginning compacting process first time.This process needs finish (compound by the brown black designation mulseal that becomes just at breakdown of emulsion) before the complete breakdown of emulsion of mulseal, otherwise the breakdown of emulsion of mulseal can cause cold recycled asphalt mixture top to form duricrust, and this will make the compacting difficulty more that becomes.
Compacting process for the second time
Temperature is the important parameter that bituminous mixture rolls, and temperature is high more, and the viscosity of bituminous material is just low more, and bituminous mixture is easy being compacted more just, thus asphalt pavement construction a lot of all in temperature than carrying out higher season.Equally, it is easier of densification that the rising of temperature also can make cold recycled asphalt mixture.
The compacting second time of basic unit occurs in the work progress of surface layer under the hot-mix asphalt mixture in the cold regeneration.After base layer construction was finished in the cold regeneration, the moisture that produces owing to the mulseal breakdown of emulsion such as need evaporate at reason, in the cold regeneration basic unit want health 10～14d time could making under surface layer.Temperature during construction is original just than higher, and through shining upon of preserving period 10～14d time, the temperature of basic unit can raise to some extent in the cold regeneration; And when down surface layer paved, the baking effect of hot-mix asphalt mixture also can make the temperature of basic unit in the cold regeneration raise.When layer hot-mix asphalt mixture rolled below, the temperature of basic unit can reach 60 ℃ in the cold regeneration, even higher.After temperature raise, cold recycled asphalt mixture was easier of densification during just than normal temperature, and road roller can produce clearly the compaction second time to basic unit in the cold regeneration to rolling of surface layer down.
Void content is that the cold recycled asphalt mixture material is formed the most important index of design, adopts following method to research and analyse the influence of compaction for the second time to basic unit's void content in the cold regeneration.
(1) after base layer construction is finished in the cold regeneration, core boring sampling and record position;
(2) after down surface construction is finished, get the core position in (1) near (apart several centimetres) get core once more;
(3) measure the void content of the cold regeneration core that drills through for twice.
The intensity of cold recycled asphalt mixture constitutes:
The mineral aggregate of cold recycled asphalt mixture is substantially all from RAP, the scope that can change is very little, and mulseal adds again, be easy to improve the intensity of cold recycled asphalt mixture, answer of the influence of primary study asphalt binder for this reason cold recycled asphalt mixture by the addition of selecting mulseal.
A kind of heterogeneous dispersion that the bituminous mixture of compaction moulding mainly is made up of mineral aggregate, bituminous cements and residual porosities with spacial framework, its material properties is a means of particulate material, and its mechanical strength depends primarily on: the cohesion of bituminous mixture and inner frictional resistance.The cohesion of bituminous mixture mainly depends on the adhesion stress of bituminous cements and the adhesion stress between pitch and the mineral aggregate, the inner frictional resistance of bituminous mixture then mainly with skeleton particle between frictional force, that power is squeezed in embedding is relevant.
(1) intensity of different structure bituminous mixture constitutes, structure according to bituminous mixture, difference by the intensity constitution principle, can be divided into the bituminous mixture that 1. structure that constitutes by the close-graded principle and the structure two big classes that constitute by the crowded principle of embedding constitute by the close-graded principle, be meant mineral aggregate and pitch cooperate by the closely knit principle of maximum after and a kind of material of forming, because fine aggregate is more, coarse aggregate is spaced and can not produces the crowded effect of embedding, and its intensity formation is the cohesion based on bituminous mixture.The dense-graded asphalt concrete road surface belongs to this type of, and the performance on this road surface is subjected to Temperature Influence relatively large; 2. squeeze the bituminous mixture of principle formation by embedding, require to adopt big, the uniform coarse aggregate of particle size.Pitch plays infilling in this compound, and mineral aggregate is bonded to as a whole.The intensity of this material mainly depends on the crowded inner frictional resistance that is produced of mutual embedding between the coarse aggregate particle, and little to the cementation dependence of pitch, with the road surface of this material making, its performance is subjected to Temperature Influence less relatively.
(2) under the condition of identical mineral aggregate character and composition, along with the raising of asphalt viscosity, the bituminous mixture cohesion can significantly increase asphalt viscosity to the influence of bituminous mixture intensity.
(3) asphalt content is to the influence of bituminous mixture intensity: after pitch and the mineral aggregate particle reciprocation, pitch produces rearranging of chemical constituent at the mineral aggregate particle surface, forms the relatively thinner diffusion solvation film of one deck at the mineral aggregate particle surface.Be called " structure pitch " at this film thickness with interior pitch, the pitch beyond this film thickness becomes " free pitch ".If the contact position is connect by the structure asphalt membrane between the mineral aggregate particle, facilitate pitch to have the contact area that film is dissolved in higher viscosity and bigger diffusion like this, thereby can obtain bigger cohesion.Otherwise,, then have less cohesion if the contact position is connect by free asphalt membrane between the mineral aggregate particle.
At asphalt content seldom the time, the film that pitch is not enough to the to form structure pitch mineral aggregate particle that bonds.Along with the increase of asphalt content, structure pitch forms gradually, and pitch is more satisfactory is wrapped in the mineral aggregate particle surface, and the intergranular adhesion stress of pitch and mineral aggregate is increased along with the increase of asphalt content.When asphalt content was enough to form film and fully adheres to the mineral aggregate particle surface, asphalt mastic had optimum cohesion.Subsequently, continue to increase as asphalt content, then because asphalt content is too much, gradually the mineral aggregate particle is pushed open, form between particle not and the interactive free pitch of mineral aggregate particle, then the cohesion of asphalt mastic reduces along with the increase of free pitch.After asphalt content increased to a certain consumption, the cohesion of bituminous mixture depended primarily on the viscosity of free pitch.Asphalt content not only influences the cohesion of bituminous mixture, also influences the inner frictional resistance of bituminous mixture simultaneously.When asphalt film reached optimum thickness, the mineral aggregate particle was bondd by structure pitch, the intergranular adhesion stress maximum of pitch and mineral aggregate, and it is also maximum that power is squeezed in the intergranular frictional force of mineral aggregate, embedding.At this moment increase asphalt content, only can improve the quantity of free pitch in the bituminous mixture, and free pitch can play the effect of sliding agent, makes mineral aggregate
Intergranular frictional force, embedding are squeezed power and are reduced, and have just reduced the inner frictional resistance of bituminous mixture.
(1) most of cold reengineer does not need adding newly to gather materials, and comprises some fine-graded materials, for the level of adjusting cold recycled asphalt mixture RAP fits over reasonable range, must add a spot of breeze.Breeze is the limestone breeze.
The match ratio design principal element of cold recycled asphalt mixture comprises best total liquid consumption.In the mulseal cold recycled asphalt mixture, the summation of mixing water, mulseal and RAP water content is called total liquid consumption, wrapping test and can determine best total liquid consumption by RAP.Add water-wet RAP compound earlier, mix and stir 30S, add mulseal again and mix and stir 60S, range estimation RAP compound wraps the minimum total liquid consumption that no longer increases and is best total liquid consumption by the proportioning of determining of mixing, and gets RAP compound 1kg.Cement consumption is 1%, 1.5%, 2% (consumption of cement normally RAP and the gross mass of newly gathering materials 1～2%) of the RAP and the gross mass of newly gathering materials, the mulseal consumption is 1%, 2%, 3%, 4%, 5% initially to wrap and mix and stir test, and definite best total liquid consumption is 6.9%.
The void content of (1) three kind of different cement consumption test specimen all reduces with the increase of mulseal consumption, is similar to the Changing Pattern of hot-mix asphalt mixture.With reference to the technical requirements 9～12% of void content, corresponding mulseal consumption was 2～3.4% (the mulseal consumption of void content technical requirements intermediate value 10.5% correspondence is about 2.5%).
(2) stability aspect, the stability of three kinds of cement consumption test specimens all present the first trend that afterwards reduces that increases with the increase of mulseal consumption.The mulseal consumption is 2.4～2.7% o'clock, and it is best that Marshall stability reaches.
(3) economic factor analysis.Five kinds of composition material RAP of mulseal cold recycled asphalt mixture, mulseal, cement, water, breeze, wherein mulseal is the main factor of its price of decision, when relying on the test road making of engineering, the every minimizing 1% of mulseal consumption, cold recycled asphalt mixture just reduces about 80 yuan/m3.
(4) determine the optimum emulsification asphalt content.Consider void content, the mulseal consumption should be 2～3.4%,
Wherein the emulsification consumption of intermediate value 10.5% correspondence of void content technical requirements is about 2.5%; The mulseal consumption of best Marshall stability correspondence is 2.4～2.7%; Economic factor then requires the mulseal consumption the smaller the better.
Claims (11)
1. a cold regeneration Emulsified Asphalt Mixture is used for the method that reconstruct on the road surface, may further comprise the steps:
At first, by field survey following deck damaged condition of surface layer and bearing capacity are carried out quantitatively evaluating, obtain actual mechanics and structural parameters, described quantitatively evaluating adopts following method to carry out:
(1) asphalt surface course is fallen in milling, utilizes the Beckman beam to measure the flexure of semi-rigid type base end face;
(2) basic unit is fallen in milling, utilizes the vertically corresponding up and down flexure of measuring the subbase end face in the point-to-point position with basic unit flexure measuring point of Beckman beam;
(3) break off the base basic unit or dig test pit of milling utilizes the modulus of the point-to-point mensuration roadbed of loaded plate end face;
(4), directly measure the thickness at basic unit and subbase flexure measuring point place at the section of milling;
(6) according to the flexure, modulus and the thickness that measure, the value of poisson's ratio parameter goes out the modulus of road surface structare layer by the finite element analysis inverse;
Wherein, the step of described limited element analysis technique is as follows: road structure is reduced to desirable mechanical model, that is: 1. elastic half-space body; 2. Elastic Layered System; 3. viscoplasticity stratiform system; 4. the plate on the elastic foundation; 5. the plate on the Elastic Layered System; Afterwards, set up mechanical model, the linear structure modulus in the employing ANSYS analysis software is analyzed the structural performance on road surface, and it defines by following formula:
{σ}＝[D]{ε
el}
In the formula:
{ σ }=stress vector=[σ
xσ
yσ
zσ
Xyσ
Yzσ
Xz];
{ ε
El}=elastic strain vector={ ε }-{ ε
Th}
[D]=elastic matrix; The inverse matrix of matrix D can be write as
Wherein:
E
xYoung's modulus of elasticity for the x direction;
V
XyPoisson's ratio for the xy plane;
G
XyModulus of shearing for the xy plane;
Afterwards, to carry out reclaimed asphalt mixture production in cold mixing factory behind old road asphalt surface course milling material, cement, mulseal and the water, it further comprises: the determining of mulseal consumption, based on the processing of three basic conditions consumption with the design mulseal, its first kind of situation, old road asphalt surface course milling material is that black gathers materials, and the mulseal of interpolation then wraps up described gathering materials fully; Second kind of situation, the consumption of mulseal should make the pitch in the old road asphalt surface course milling material return to its initial viscosity, and promptly aged asphalt is all softening; The third situation is the combination of preceding two kinds of situations, and promptly the pitch that part is aging takes place to soften, and the mechanics according to cold regeneration mix requires test to determine the consumption of mulseal again; At normal temperatures with various composition material uniform mixings;
In order to improving the cement of cold recycled asphalt mixture stiffness and anti-damage by water ability, addition is to comprise 1～2% of the reclaimed asphalt mixture gross mass of newly gathering materials;
Reclaimed asphalt mixture detects by shaping test piece;
The compound of above-mentioned steps gained is used to road structure to be reconstructed, comprises the making of roadbed, basic unit and surface layer.
2. according to the described method of claim 1, it is characterized in that, comprise that the mulseal consumption should make in Marshall stability and flow valuve, indirect tensile strength, compressive strength, the modulus of resilience one or several reach road surface type design parameter; Selected mulseal consumption makes the void content of cold regeneration mix 9～12%.
3. according to the described method of claim 1, it is characterized in that, the step of reclaimed asphalt mixture shaping test piece comprises: the cold regeneration mix test specimen is distributed redundant moisture and health to reach the demoulding after the corresponding strength, test specimen should be stayed in the compacting mould and be sidelong during health, health is divided into short-term health and two kinds of long-term healths again, simulate the short-term performance and the long-term behaviour of cold regeneration mix respectively, the density of test specimen is similar to the compacted density of on-the-spot compound.
4. according to the described method of claim 3, it is characterized in that described short-term health is that test specimen is placed on 2～4h under 60 ℃ of environment; Long-term health then is to place 24～48h under 60 ℃ of environment.
5. according to the described method of claim 1, it is characterized in that, the described making of waiting to reconstruct the road surface, the compacting process of basic unit comprises in its cold regeneration:
Compacting for the first time: cold recycled asphalt mixture rolls by road roller after paving and finishing, and this process is finished before the complete breakdown of emulsion of mulseal;
Compacting for the second time, under hot-mix asphalt mixture, carry out in the work progress of surface layer, basic unit's health surface layer under the making after 10～14 days in the cold regeneration, be easy at cold recycled asphalt mixture under the higher temperature of densification, following rolling indirectly of surface layer carried out the compacting second time to basic unit in the cold regeneration by road roller.
6. the cold recycled asphalt mixture that is adopted as one of claim 1 to 5 method, it is characterized in that, constitute by old road asphalt surface course milling material, cement, mulseal and water mixing, wherein, the bituminous mixture of compaction moulding is formed the heterogeneous dispersion structure with spacial framework by the mineral aggregate, bituminous cements and the residual porosities that mainly constitute with old road asphalt surface course milling material, its material properties is a means of particulate material, and its cohesion and inner frictional resistance by bituminous mixture reaches its mechanical strength.
7. according to the described method of claim 6, it is characterized in that described mineral aggregate also comprises the limestone breeze.
8. according to the described method of claim 6, it is characterized in that, described cold recycled asphalt mixture comprises total liquid consumption that the summation of mixing water, mulseal and old road asphalt surface course milling material water content constitutes, its total consumption is by adding water-wet old road asphalt surface course milling material, mix and stir 30S, add mulseal again and mix and stir 60S, the range estimation compound wraps the minimum total liquid consumption that no longer increases and determines.
9. described according to Claim 8 method is characterized in that, described total liquid consumption is 6.9%.
10. according to the described method of claim 6, it is characterized in that cement consumption is the old road asphalt surface course milling material and 1～2% of the gross mass of newly gathering materials.
11., it is characterized in that described mulseal consumption is 2～3.4% according to the described method of claim 6.
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103526665A (en) * | 2013-09-30 | 2014-01-22 | 沧州市市政工程公司 | Accurate preparation method of emulsified asphalt cold recycled mixture |
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| CN102531471A (en) * | 2010-12-31 | 2012-07-04 | 上海龙孚材料技术有限公司 | Emulsified asphalt, mixed material containing same and road surface formed by mixed material |
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| CN110110495B (en) * | 2019-06-10 | 2022-11-25 | 交通运输部公路科学研究所 | Inverse calculation method for synchronously determining asphalt pavement structure layer modulus and asphalt surface layer Poisson ratio |
| CN111537418B (en) * | 2020-04-27 | 2022-09-23 | 哈尔滨工业大学 | Method for evaluating grouting performance of cement asphalt composite concrete cementing material |
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| CN111636282A (en) * | 2020-07-13 | 2020-09-08 | 长安大学 | Method for implementing pavement maintenance based on in-situ softening technology of semi-rigid pavement base |
| CN114438856A (en) * | 2020-11-03 | 2022-05-06 | 江苏北极星交通产业集团有限公司 | Cold regeneration process for plant-mixed high-performance asphalt surface layer |
| CN113636805A (en) * | 2021-07-12 | 2021-11-12 | 江苏中亿通道路新材料有限公司 | Preparation method of normal-temperature mixing type emulsified asphalt mixture |
| CN113866018A (en) * | 2021-09-28 | 2021-12-31 | 太原理工大学 | Test system and method for testing mechanical properties of RAP and emulsified asphalt interface |
| CN115201250B (en) * | 2022-09-14 | 2022-11-25 | 中铁三局集团第三工程有限公司 | Quantification method for thermal reversible aging degree of cold-recycling asphalt mixture |
| CN116678769B (en) * | 2023-07-27 | 2023-10-31 | 北京工业大学 | Method for determining repair time of asphalt pavement |
-
2009
- 2009-12-16 CN CN2009102424676A patent/CN101748677B/en active Active
Non-Patent Citations (1)
| Title |
|---|
| 曹丽萍等.乳化沥青冷再生混合料初期性能评价.《石油沥青》.2007,第21卷(第1期), * |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103526665A (en) * | 2013-09-30 | 2014-01-22 | 沧州市市政工程公司 | Accurate preparation method of emulsified asphalt cold recycled mixture |
| CN103526665B (en) * | 2013-09-30 | 2016-01-20 | 沧州市市政工程股份有限公司 | A kind of preparation method of Cold Recycled Mixture with Emulsified Asphalt accurately |
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