CN113128026B - High-temperature creep and low-temperature relaxation performance balance design method for recycled asphalt mixture - Google Patents

High-temperature creep and low-temperature relaxation performance balance design method for recycled asphalt mixture Download PDF

Info

Publication number
CN113128026B
CN113128026B CN202110304181.7A CN202110304181A CN113128026B CN 113128026 B CN113128026 B CN 113128026B CN 202110304181 A CN202110304181 A CN 202110304181A CN 113128026 B CN113128026 B CN 113128026B
Authority
CN
China
Prior art keywords
asphalt mixture
creep
temperature
relaxation
low
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Active
Application number
CN202110304181.7A
Other languages
Chinese (zh)
Other versions
CN113128026A (en
Inventor
李雪连
罗桑
叶峻宏
张显安
鲁巍巍
夏建芳
王随原
王文强
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Changsha University of Science and Technology
Original Assignee
Changsha University of Science and Technology
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Changsha University of Science and Technology filed Critical Changsha University of Science and Technology
Priority to CN202110304181.7A priority Critical patent/CN113128026B/en
Publication of CN113128026A publication Critical patent/CN113128026A/en
Application granted granted Critical
Publication of CN113128026B publication Critical patent/CN113128026B/en
Active legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Images

Classifications

    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06F—ELECTRIC DIGITAL DATA PROCESSING
    • G06F30/00—Computer-aided design [CAD]
    • G06F30/20—Design optimisation, verification or simulation
    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06F—ELECTRIC DIGITAL DATA PROCESSING
    • G06F2113/00—Details relating to the application field
    • G06F2113/26—Composites
    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06F—ELECTRIC DIGITAL DATA PROCESSING
    • G06F2119/00—Details relating to the type or aim of the analysis or the optimisation
    • G06F2119/08—Thermal analysis or thermal optimisation

Landscapes

  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Theoretical Computer Science (AREA)
  • Computer Hardware Design (AREA)
  • Evolutionary Computation (AREA)
  • Geometry (AREA)
  • General Engineering & Computer Science (AREA)
  • General Physics & Mathematics (AREA)
  • Working-Up Tar And Pitch (AREA)
  • Compositions Of Macromolecular Compounds (AREA)

Abstract

The invention discloses a design method for balancing high-temperature creep and low-temperature relaxation performance of a recycled asphalt mixture, which comprises the following steps: drafting RAP mixing amount; determining the initial oilstone ratio and the mixing amount of the regenerant; preparing n groups of different regenerated asphalt mixtures; testing to obtain creep index and relaxation index values of the original asphalt mixture and the regenerated asphalt mixture; standardizing creep index and relaxation index value of the recycled asphalt mixture to eliminate the influence of different index dimensions; calculating the balance point of the high-temperature creep and low-temperature relaxation performance; comparing the high-temperature creep and low-temperature relaxation performance of the regenerated asphalt mixture at the equilibrium point with that of the original asphalt mixture; the optimum balance point of high temperature creep and low temperature relaxation behavior is determined. The invention starts from viscoelastic property, carries out balance design on the recycled asphalt mixture, determines the mixing amount of the regenerant and the original asphalt under different RAP mixing amounts, and provides a new idea for the design of the recycled asphalt mixture.

Description

High-temperature creep and low-temperature relaxation performance balance design method for recycled asphalt mixture
Technical Field
The invention belongs to the technical field of design of a recycled asphalt mixture, and particularly relates to a design method for balancing high-temperature creep and low-temperature relaxation performance of a recycled asphalt mixture.
Background
With the successive step of major repair or reconstruction of the roads of various levels built in China, the recycling of waste asphalt mixtures is a necessary trend. But aged bitumen in RAP (reclaimed old bituminous material) exhibits higher stiffness and lower stress relaxation capacity due to excessive oxidation. Therefore, in order to improve the road performance of the reclaimed asphalt mix, it is generally necessary to add a rejuvenating agent, new asphalt, new aggregate, and the like to the RAP. The composition of the mixture is more complex, so that the difference of the performance of the mixture and the original asphalt mixture is larger, and the performance of the recycled asphalt mixture is difficult to accurately evaluate by the traditional evaluation index based on the strength theory or the deformation theory.
Under the influence of factors such as earth latitude, solar illumination, seasonal variation and the like, the service environment of most asphalt pavements in China is in an area with summer inflammation and winter coldness. Moreover, the fact proves that the asphalt pavement is easy to generate ruts at high temperature and crack at low temperature. The high-temperature performance of the recycled asphalt mixture after the RAP is mixed is generally better, but the risk of low-temperature cracking of the pavement is increased, so the low-temperature performance of the recycled asphalt mixture is improved as much as possible. In general, the high and low temperature properties in asphalt mixtures are contradictory, namely: when one of the performances is improved, the other performance is reduced. Therefore, it is very important to design the high and low temperature performance of the reclaimed asphalt mixture in a balanced manner.
At present, most of researches on the high and low temperature performance balance design of the recycled asphalt mixture are based on rutting and crack resistance tests, and the high and low temperature performance balance design method of the recycled mixture at present has the following limitations: 1) the performance of the recycled asphalt mixture is difficult to accurately evaluate by evaluation indexes based on a strength theory or a deformation theory; 2) only the mixing amount of different RAPs is considered, and the influence of the mixing amounts of three materials, namely RAP, a regenerant and asphalt, is not comprehensively considered; 3) generally, the upper and lower limit values of the high and low temperature performance indexes are respectively determined according to specifications, and finally, the median value or the intersection point of the high and low temperature performance indexes is selected as a balance value in a limited range, so that the reliability and the precision of the balance design are poor.
Chinese patent 201811064240.2 discloses a method for determining the amount of asphalt regenerant based on rheological property balance design, which comprises adding regenerant to regenerate old asphalt, testing the composite shear modulus G, high-temperature unrecoverable creep compliance Jnr-3.2, fatigue failure life Nf, low-temperature relaxation modulus G (t) and relaxation rate mr (t) of the regenerated asphalt, and finally determining the optimal amount of the regenerant according to the indexes. However, the above patents have the following limitations: (1) the mechanical characteristics and rheological models of the asphalt and the asphalt mixture are obviously different, and the determination of the mixing amount of the regenerant only by adopting the asphalt lacks the practical significance; (2) the mixing amount of the regenerant is determined only by the regeneration of aged asphalt, and RAP regeneration and original asphalt all play a very important role (3) the representative requirements can be met only by extracting and recovering old asphalt from a large amount of milling material RAP, and the process is complicated and the workload is large.
Disclosure of Invention
The invention mainly aims to provide a design method for balancing high-temperature creep and low-temperature relaxation performance of a regenerated asphalt mixture, which determines the optimal mixing amount of green of the regenerated asphalt mixture from the viewpoint of viscoelastic performance of the asphalt mixture and makes up the defects of the conventional method.
In order to solve the technical problem, the invention adopts the following technical scheme:
a design method for balancing high-temperature creep and low-temperature relaxation performance of a recycled asphalt mixture comprises the following steps:
s1: planning the mixing amount of RAP, wherein RAP refers to the recovered old asphalt material;
s2: determining initial OAC and ORA according to the mix proportion design;
wherein, OAC refers to the oil-stone ratio, ORA refers to the mixing amount of the regenerant;
s3: preparing n groups of different regenerated asphalt mixtures;
s4: testing and measuring creep and relaxation index value epsilon of original asphalt mixturep/FNVAnd tsVAnd creep and relaxation index values ε of n groups of recycled asphalt mixturesp/FNiAnd tSi；
Wherein epsilonp/FNVDenotes the creep index, t, of the as-received asphalt mixturesVDenotes the relaxation index value, epsilon, of the original asphalt mixturep/FNiDenotes the creep index, t, of each group of recycled asphalt mixturessiThe relaxation index value of each group of regenerated asphalt mixture is represented, i is 1,2, …, n;
s5: observing the variation trend of the creep and relaxation index values of the n groups of regenerated asphalt mixtures, and analyzing the variation rule;
s6: carrying out standardization treatment on creep and relaxation index values of the n groups of regenerated asphalt mixtures;
s7: calculating the sum l of the distances between the creep and relaxation index values of the standardized recycled asphalt mixture and 0.5, and then comparing the sum l with the creep and relaxation index values of the original asphalt mixture;
s8: and determining an optimal balance point of high-temperature creep and low-temperature relaxation performance, wherein the OAC and ORA corresponding to the optimal balance point are the optimal mixing amount of the regenerant and the oilstone ratio under the planned RAP mixing amount.
Specifically, in the step S7, when the creep and relaxation index values of the normalized recycled asphalt mixture and the original asphalt mixture are compared, the following cases may occur:
in the case of the first situation, the first,
Figure GDA0003647504820000031
and is
Figure GDA0003647504820000032
Namely, the high-temperature creep and low-temperature relaxation performance of the regenerated asphalt mixture are superior to those of the original asphalt mixture;
in the case of the second situation, the first situation,
Figure GDA0003647504820000033
and is
Figure GDA0003647504820000034
Namely, the low-temperature relaxation performance of any recycled asphalt mixture is inferior to that of the original asphalt mixture, but the high-temperature creep performance of the recycled asphalt mixture is superior to that of the original asphalt mixture;
in the case of the third situation, the first,
Figure GDA0003647504820000035
and is
Figure GDA0003647504820000036
Namely, the high-temperature creep and low-temperature relaxation performance of any recycled asphalt mixture is inferior to that of the original asphalt mixture;
in the case of the fourth situation,
Figure GDA0003647504820000037
and is
Figure GDA0003647504820000038
I.e. any reclaimed asphalt mixture has a higher high temperature creep performance than the as-received asphalt mixture, but there is a group with a higher low temperature relaxation performance than the as-received asphalt mixture.
Specifically, the optimal balance point in step S8 is divided into the following cases:
if this is the case one, inp/FNi＜εp/FNVAnd t issi＜tsVTaking the minimum value point of the value l as the optimal balance point;
if the case is two, inp/FNi＜εp/FNVUnder the condition of (b), tsiTaking the minimum value point as the optimal balance point;
if the case is three, inp/FNi＞εp/FNVAnd t issi＞tsVTaking the minimum value point as the optimal balance point;
if the case is four, at tsi＜tsVUnder the condition of (b) ∈p/FNiAnd taking the minimum value point as the optimal balance point.
Specifically, the specific process of step S6 is as follows:
respectively recording creep and relaxation index values of n groups of recycled asphalt mixtures as original sequences { epsilonp/FN1,εp/FN2,…,εp/FNnAnd ts1,ts2,…,tsnAdopting Min-maxirmanization function to carry out standardized operationThen, as shown in formula (1), the normalized creep and relaxation index value results are respectively recorded as a new sequence { εp/FN1',εp/FN2',…,εp/FNn' } and { ts1',ts2',…,tsn'}；
Figure GDA0003647504820000039
In the formula: x-original sequence { x1,x2,…,xn}；
y-New sequence { y1,y2,…,yn}∈[0,1]And is dimensionless.
Specifically, the calculation formula of l in step S7 is as follows:
li＝|εp/FNi'-0.5|+|tsi'-0.5| (2)
in the formula: li-sum of distances of group i;
εp/FNi' -normalized values for the i-th set of creep indicators;
tsi' -normalized values for the i-th set of relaxation indicators.
Specifically, the specific process for preparing n groups of different recycled asphalt mixtures comprises the following steps: on the basis of initial OAC and ORA, the oilstone ratio and the regenerant are respectively increased in proportion to ensure that the oilstone ratio and the regenerant have k groups of different doping amounts, each level of the oilstone ratio and each level of the regenerant are combined in a cross mode and are doped into the mixture once, and finally n groups of different regenerated asphalt mixtures are prepared, wherein n is k multiplied by k, and k is more than or equal to 3.
Specifically, the creep and relaxation indicators are obtained as follows: respectively carrying out high-temperature creep and low-temperature relaxation tests on the original asphalt mixture and the n groups of regenerated asphalt mixtures to obtain creep and relaxation index values epsilon of the original asphalt mixturep/FNVAnd tsNAnd creep and relaxation index values ε of n groups of recycled asphalt mixturesp/FNiAnd tsi。
Compared with the prior art, the invention has the advantages that:
1. the invention provides a design method for balancing high-temperature creep and low-temperature relaxation performance of a recycled asphalt mixture from the perspective of the contradictory relation between the high-temperature creep and the low-temperature relaxation. Compared with indirect evaluation by adopting asphalt balance design, the method can directly carry out balance design on the recycled asphalt mixture, and the result is more convincing.
2. The invention provides a method for determining the green optimum mixing amount of the recycled asphalt mixture from the viewpoint of the viscoelasticity performance of the asphalt mixture, and makes up for the defects of the conventional method.
3. According to the method, the evaluation indexes are standardized, so that two indexes with different properties, namely high-temperature creep and low-temperature relaxation, can be directly compared, and the accuracy of the result is greatly improved.
4. In the invention, abstract balance is converted into distance comparison, so that the method is simple and easy to operate, and the visualization of balance points on a geometric figure is realized, thereby being more intuitive.
5. Compared with the existing method, the method is simpler, easy to operate and strong in feasibility; and the asphalt mixture belongs to a typical viscoelastic plastic material, so the evaluation method based on creep and relaxation tests is more accurate than the evaluation method based on strength and deformation theory.
According to the invention, by utilizing the characteristic that the asphalt mixture belongs to a typical viscoelastic-plastic material and can generate creep deformation and relaxation under the action of load and temperature, the actual mechanical state of the asphalt pavement in the use environment can be well characterized by adopting a creep deformation and relaxation test, and the high-low temperature performance of the regenerated asphalt mixture can be further evaluated.
Drawings
In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings needed to be used in the description of the embodiments will be briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without creative efforts.
FIG. 1 is a technical roadmap for an embodiment of the present invention;
FIG. 2 is the epsilon of 20% RAP reclaimed asphalt mix and as received asphalt mixp/FNAnd ts；
FIG. 3 is the epsilon of 30% RAP reclaimed asphalt mix and as received asphalt mixp/FNAnd ts；
FIG. 4 is the ε of a 50% RAP reclaimed asphalt mix and an as received asphalt mixp/FNAnd ts。
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
In the description of the present invention, it is to be understood that the terms "central," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," "circumferential," and the like are used in the orientations and positional relationships indicated in the drawings for convenience in describing the invention and to simplify the description, and are not intended to indicate or imply that the referenced devices or elements must have a particular orientation, be constructed and operated in a particular orientation, and are therefore not to be considered limiting of the invention.
Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of the present invention, "a plurality" means two or more unless specifically defined otherwise.
Referring to fig. 1, a design method for balancing high-temperature creep and low-temperature relaxation performance of a recycled asphalt mixture comprises the following steps:
s1: according to actual needs, the mixing amount of RAP (recycled old asphalt material) is planned;
s2: determining an initial oilstone ratio (OAC) and a regenerant dosage (ORA) according to a mixing ratio design;
s3: on the basis of S1 and S2, referring to the practical engineering application condition, the oilstone ratio and the regenerant are respectively increased in proportion, so that the oilstone ratio and the regenerant have k groups of different doping amounts (containing OAC and ORA). And each level of the oil-stone ratio and each level of the regenerant are combined in a cross mode and are blended into the mixture once, and finally n groups of different recycled asphalt mixtures are prepared.
S4: respectively carrying out high-temperature creep and low-temperature relaxation tests on the original asphalt mixture and the n groups of regenerated asphalt mixtures to obtain creep and relaxation index values epsilon of the original asphalt mixturep/FNVAnd tsVAnd creep and relaxation index values epsilon of n groups of recycled asphalt mixturesp/FNiAnd tSi(i＝1,2,…,n)。
Wherein epsilonp/FNVDenotes the creep index, t, of the as-received asphalt mixturesVDenotes the relaxation index value, epsilon, of the original asphalt mixturep/FNiDenotes the creep index, t, of each group of recycled asphalt mixturessiThe relaxation index value of each group of regenerated asphalt mixture is represented, i is 1,2, …, n;
s5: observing the variation trend of the creep and relaxation index values of the n groups of regenerated asphalt mixtures, and analyzing the variation rule;
s6: carrying out standardization treatment on creep and relaxation index values of the n groups of regenerated asphalt mixtures; the influence of different index dimensions is eliminated, so that the index values are in the same quantity level, and comprehensive evaluation and analysis are facilitated. The specific implementation method comprises the following steps:
respectively recording creep and relaxation index values of n groups of recycled asphalt mixtures as original sequences { epsilonp/FN1,εp/FN2,…,εp/FNnAnd { t }s1,ts2,…,tsnAnd (5) adopting a Min-max normalization function to carry out normalization operation, as shown in a formula (1), and respectively recording the normalized creep and relaxation index value results as a new sequence { epsilonp/FN1',εp/FN2',…,εp/FNn' } and { ts1',ts2',…,tsn'}。
Figure GDA0003647504820000061
In the formula: x-original sequence { x1,x2,…,xn}；
y-New sequence { y1,y2,…,yn}∈[0,1]And is dimensionless.
Further, calculate { εp/FN1',εp/FN2',…,εp/FNn' } and { ts1',ts2',…,tsnThe sum of the distances between/and 0.5 (the median of the set of new sequences after normalization, representing the general level of performance for this set), is calculated as shown in equation (2).
li＝|εp/FNi'-0.5|+|tsi'-0.5| (2)
In the formula: li-sum of distances of group i;
εp/FNi' -normalized values for the i-th set of creep indicators;
tsi' -normalized value of the i-th group relaxation index.
S7: calculating the sum l of the distances between the creep and relaxation index values of the standardized recycled asphalt mixture and 0.5, and then comparing the sum l with the creep and relaxation index values of the original asphalt mixture;
as a result, the following may occur:
in the first place, the first,
Figure GDA0003647504820000071
and is
Figure GDA0003647504820000072
Namely, the high-temperature creep and low-temperature relaxation performance of the regenerated asphalt mixture are superior to those of the original asphalt mixture;
in the second place, the first place is,
Figure GDA0003647504820000073
and is
Figure GDA0003647504820000074
Namely, the low-temperature relaxation performance of any recycled asphalt mixture is inferior to that of the original asphalt mixture, but the high-temperature creep performance of the recycled asphalt mixture is superior to that of the original asphalt mixture;
in the third place, the first place is,
Figure GDA0003647504820000075
and is
Figure GDA0003647504820000076
Namely the high-temperature creep and low-temperature relaxation performance of any recycled asphalt mixture is inferior to that of the original asphalt mixture;
in the fourth place, the first step is,
Figure GDA0003647504820000077
and is
Figure GDA0003647504820000078
I.e. any reclaimed asphalt mixture has a higher high temperature creep performance than the as-received asphalt mixture, but there is a group with a higher low temperature relaxation performance than the as-received asphalt mixture.
S8: and determining an optimal balance point of high-temperature creep and low-temperature relaxation performance, wherein the OAC and ORA corresponding to the optimal balance point are the optimal mixing amount of the regenerant and the oilstone ratio under the planned RAP mixing amount.
Wherein, in the first or third case, inp/FNi＜εp/FNVAnd t issi＜tsVTaking the minimum value (namely, the point closest to 0.5) as the optimal balance point; in the second case, inp/FNi＜εp/FNVUnder the condition of (1), tsiTaking the minimum value point as the optimal balance point, namely taking the optimal point of the relaxation performance as the optimal balance point on the premise of ensuring the creep performance; in the fourth case, at tsi＜tsVUnder the condition of (2), epsilonp/FNiAnd taking the minimum value point as the optimal balance point, namely taking the creep performance optimal point as the optimal balance point on the premise of ensuring the relaxation performance.
The present invention will be further described with reference to the following specific examples.
Example 1
A design method for balancing high-temperature creep and low-temperature relaxation performance of a recycled asphalt mixture comprises the following steps:
the first step is as follows: drafting RAP mixing amount;
the embodiment adopts a 20 percent RAP mixing amount of the recycled asphalt mixture.
The second step is that: determining initial oilstone ratio (OAC) and regenerant dosage (ORA)
The initial OAC and ORA were determined to be 5.13% and 4.0%, respectively, based on the mix design.
The third step: preparing n groups of different regenerated asphalt mixture test pieces
On the basis of OAC and ORA, referring to the practical engineering application situation, the oilstone ratio and the regenerant are respectively increased in proportion to have 3 groups of different mixing amounts (containing OAC and ORA), each level of the oilstone ratio and each level of the regenerant are combined in a cross mode and are mixed into the mixture once, and finally 9 groups of different recycled asphalt mixtures are prepared, wherein the different recycled asphalt mixtures are shown in the table 1.
TABLE 1
Figure GDA0003647504820000081
Figure GDA0003647504820000091
The fourth step: acquiring high-temperature creep and low-temperature relaxation indexes of the original asphalt mixture and the regenerated asphalt mixture;
carrying out triaxial compression repeated creep and direct tensile stress relaxation tests on the original asphalt mixture and the regenerated asphalt mixture test piece to obtain a creep index value epsilon of the original asphalt mixture and the regenerated asphalt mixturep/FNVAnd εp/FNi(i ═ 1,2, …, n), and relaxation index values t for the as-received asphalt mix and the reclaimed asphalt mixsVAnd tsi(i＝1,2,…,n)。
The fifth step: standardizing creep indexes and relaxation indexes of the recycled asphalt mixture to eliminate the influence of different index dimensions;
the epsilon of the 1# -9# recycled asphalt mixture is processed according to the standardized processing formulap/FNiAnd tSiThe raw data sequence was normalized and the results are shown in table 2 below.
TABLE 220% RAP normalization processing results
Figure GDA0003647504820000092
And a sixth step: comparing the high temperature creep and low temperature relaxation performance of the recycled asphalt mixture with the original asphalt mixture, as shown in fig. 2;
the seventh step: calculating the value of l according to the formula (2);
as can be seen from FIG. 2, ε of 2#, 4#, 5#, and 7#, respectivelyp/FNAnd tsAll values are less than epsilon of the original asphalt mixturep/FNAnd tsThe values show that the high-temperature creep and the low-temperature relaxation performance of the asphalt are superior to those of the original asphalt mixture. According to the balance design method, the first condition is satisfied,
Figure GDA0003647504820000101
and is
Figure GDA0003647504820000102
I.e. there is a group where the high temperature creep and low temperature relaxation properties of the reclaimed asphalt mix are better than the as-received asphalt mix. The analysis shows that the 2# reclaimed asphalt mixture is the best grade of the 20% RAP reclaimed asphalt mixtureAnd (5) balancing points.
Example 2
A design method for balancing high-temperature creep and low-temperature relaxation performance of a recycled asphalt mixture comprises the following steps:
the first step is as follows: drawing up the RAP mixing amount;
the embodiment adopts a 30 percent RAP mixing amount of the regenerated asphalt mixture.
The second step is that: determining initial oilstone ratio (OAC) and regenerant dosage (ORA)
The initial OAC and ORA were determined to be 5.15% and 4.0%, respectively, based on the mix design.
The third step: preparing n groups of different regenerated asphalt mixture test pieces
On the basis of OAC and ORA, referring to the practical engineering application situation, the oilstone ratio and the regenerant are respectively increased in proportion to have 3 groups of different mixing amounts (containing OAC and ORA), each level of the oilstone ratio and each level of the regenerant are combined in a cross mode and are mixed into the mixture once, and finally 9 groups of different recycled asphalt mixtures are prepared, wherein the different recycled asphalt mixtures are shown in the table 3.
TABLE 3
Figure GDA0003647504820000103
Figure GDA0003647504820000111
The fourth step: acquiring high-temperature creep and low-temperature relaxation indexes of the original asphalt mixture and the regenerated asphalt mixture;
carrying out triaxial compression repeated creep and direct tensile stress relaxation tests on the original asphalt mixture and the regenerated asphalt mixture test piece to obtain creep index values epsilon of the original asphalt mixture and the regenerated asphalt mixturep/FNVAnd εp/FNi(i ═ 1,2, …, n), and relaxation index values t for the as-received asphalt mix and the reclaimed asphalt mixsVAnd tsi(i＝1,2,…,n)。
The fifth step: the creep index and the relaxation index of the recycled asphalt mixture are standardized to eliminate the influence of different index dimensions;
the epsilon of the 10# -18# recycled asphalt mixture is processed according to the standardized processing formulap/FNiAnd tsiThe raw data sequence was normalized and the results are shown in table 4 below;
TABLE 430% RAP normalization processing results
Figure GDA0003647504820000112
Figure GDA0003647504820000121
And a sixth step: comparing the high temperature creep and low temperature relaxation performance of the recycled asphalt mixture with that of the original asphalt mixture, as shown in fig. 3;
the seventh step: calculating the value of l according to the formula (2);
as can be seen from FIG. 3,. epsilon.of # 15 and # 17p/FNAnd tsAll values are less than epsilon of the original asphalt mixturep/FNAnd tsThe values show that the high-temperature creep and the low-temperature relaxation performance of the asphalt are superior to those of the original asphalt mixture. According to the balance design method, the first condition is satisfied,
Figure GDA0003647504820000122
and is provided with
Figure GDA0003647504820000123
I.e. there is a group where the high temperature creep and low temperature relaxation properties of the reclaimed asphalt mix are better than the as-received asphalt mix. Analysis shows that the No. 17 recycled asphalt mixture is the optimal balance point of the 30% RAP recycled asphalt mixture.
Example 3
A design method for balancing high-temperature creep and low-temperature relaxation performance of a recycled asphalt mixture comprises the following steps:
the first step is as follows: drafting RAP mixing amount;
the embodiment adopts the regenerated asphalt mixture with 50 percent of RAP mixing amount.
The second step: determining initial oilstone ratio (OAC) and regenerant dosage (ORA)
The initial OAC and ORA were determined to be 5.20% and 4.0%, respectively, based on the mix design.
The third step: preparing n groups of different regenerated asphalt mixture test pieces
On the basis of OAC and ORA, referring to the practical engineering application situation, the oilstone ratio and the regenerant are respectively increased in proportion to have 3 groups of different mixing amounts (containing OAC and ORA), each level of the oilstone ratio and each level of the regenerant are combined in a cross mode and are mixed into the mixture once, and finally 9 groups of different recycled asphalt mixtures are prepared, as shown in Table 5.
TABLE 5
Packet numbering Oilstone ratio (%) + regenerant content (%)
19# 5.20％+4.0％
20# 5.20％+4.5％
21# 5.20％+5.0％
22# 5.30％+4.0％
23# 5.30％+4.5％
24# 5.30％+5.0％
25# 5.80％+4.0％
26# 5.80％+4.5％
27# 5.80％+5.0％
The fourth step: acquiring high-temperature creep and low-temperature relaxation indexes of the original asphalt mixture and the regenerated asphalt mixture;
carrying out triaxial compression repeated creep and direct tensile stress relaxation tests on the original asphalt mixture and the regenerated asphalt mixture test piece to obtain creep index values epsilon of the original asphalt mixture and the regenerated asphalt mixturep/FNVAnd epsilonp/FNi(i-1, 2, …, n) and the relaxation index values t for the as-received and reclaimed asphalt mixessVAnd tsi(i＝1,2,…,n)。
The fifth step: the creep index and the relaxation index of the recycled asphalt mixture are standardized to eliminate the influence of different index dimensions;
the epsilon of the 19# -27# reclaimed asphalt mixture is processed according to the standardized processing formula shown abovep/FNiAnd tSiThe raw data sequence was normalized and the results are shown in table 6 below;
TABLE 650% RAP normalization results
Figure GDA0003647504820000141
And a sixth step: comparing the high-temperature creep and low-temperature relaxation performance of the regenerated asphalt mixture at the equilibrium point with that of the original asphalt mixture, as shown in fig. 4;
the seventh step: calculating the value of l according to the formula (2);
as can be seen from FIG. 4, ε of all groupsp/FNHaving a value less than epsilon of the as-received bituminous mixturep/FNThe values show that the high temperature creep property of the asphalt mixture is better than that of the original asphalt mixture. However, t of all groupssValue greater than as-received asphalt mixture tsThe value, and therefore the low temperature relaxation performance of a reclaimed asphalt mix containing 50% RAP, is inferior to that of an as-received asphalt mix. As can be seen from the balanced design method, in accordance with the second case,
Figure GDA0003647504820000142
and is
Figure GDA0003647504820000143
I.e., any reclaimed asphalt mixture has lower low temperature relaxation properties than the as-received asphalt mixture, but there is a group with higher high temperature creep properties than the as-received asphalt mixture. Then at epsilonp/FNi＜εp/FNVUnder the condition of (1), tsiAnd taking the minimum value point as the optimal balance point, namely taking the optimal point of the relaxation performance as the optimal balance point on the premise of ensuring the creep performance. According to the balance analysis result, the 27# recycled asphalt mixture is the optimal balance point of the 50% RAP recycled asphalt mixture.
Any embodiment disclosed herein above is meant to disclose, unless otherwise indicated, all numerical ranges disclosed as being preferred, and any person skilled in the art would understand that: the preferred ranges are merely those values which are obvious or representative of the technical effects which can be achieved. Since the number is large and cannot be exhaustive, some of the numbers are disclosed to exemplify the technical solutions of the present invention, and the above-mentioned numbers should not be construed as limiting the scope of the present invention.
Meanwhile, if the invention as described above discloses or relates to parts or structural members fixedly connected to each other, the fixedly connected parts can be understood as follows, unless otherwise stated: a detachable fixed connection (for example using bolts or screws) is also understood as: non-detachable fixed connections (e.g. riveting, welding), but of course, fixed connections to each other may also be replaced by one-piece structures (e.g. manufactured integrally using a casting process) (unless it is obviously impossible to use an integral forming process).
In addition, terms used in any technical solutions disclosed in the present invention to indicate positional relationships or shapes include approximate, similar or approximate states or shapes unless otherwise stated. Any part provided by the invention can be assembled by a plurality of independent components or can be manufactured by an integral forming process.
The above examples are merely illustrative for clearly illustrating the present invention and are not intended to limit the embodiments. Other variations and modifications will be apparent to persons skilled in the art in light of the above description. Nor is it necessary or exhaustive for all embodiments. And obvious variations or modifications of the invention may be made without departing from the scope of the invention.

Claims (7)

1. The design method for balancing the high-temperature creep property and the low-temperature relaxation property of the recycled asphalt mixture is characterized by comprising the following steps of:
s1: planning the mixing amount of RAP, wherein RAP refers to the recovered old asphalt material;
s2: determining initial OAC and ORA according to the mix proportion design;
wherein, OAC refers to the oil-stone ratio, ORA refers to the mixing amount of the regenerant;
s3: preparing n groups of different regenerated asphalt mixtures;
s4: testing and measuring creep and relaxation index value epsilon of original asphalt mixturep/FNVAnd tsVAnd creep and relaxation index values ε of n groups of recycled asphalt mixturesp/FNiAnd tsi；
Wherein epsilonp/FNVDenotes the creep index, t, of the as-received asphalt mixturesVIndicates the relaxation index value of the original asphalt mixture，εp/FNiDenotes the creep index, t, of each group of recycled asphalt mixturessiThe relaxation index value of each group of regenerated asphalt mixture is represented, i is 1,2, …, n;
s5: observing the variation trend of the creep and relaxation index values of the n groups of regenerated asphalt mixtures, and analyzing the variation rule;
s6: carrying out standardization treatment on creep and relaxation index values of the n groups of regenerated asphalt mixtures;
s7: calculating the sum l of the distances between the creep and relaxation index values of the standardized recycled asphalt mixture and 0.5, and then comparing the sum l with the creep and relaxation index values of the original asphalt mixture;
s8: and determining the optimal balance point of high-temperature creep and low-temperature relaxation performance, wherein the OAC and ORA corresponding to the optimal balance point are the optimal mixing amount of the regenerant and the oilstone ratio under the formulated RAP mixing amount.
2. The method for designing the balance of the high-temperature creep and the low-temperature relaxation performance of the recycled asphalt mixture according to claim 1, wherein the method comprises the following steps: comparing the creep and relaxation index values of the normalized recycled asphalt mixture with the original asphalt mixture as described in step S7 may be as follows:
in the case of the first one of the cases,
Figure FDA0003647504810000011
and is
Figure FDA0003647504810000012
Namely, the high-temperature creep and low-temperature relaxation performance of the regenerated asphalt mixture are superior to those of the original asphalt mixture;
in the case of the second situation, the first situation,
Figure FDA0003647504810000013
and is
Figure FDA0003647504810000014
Namely, the low-temperature relaxation performance of any recycled asphalt mixture is inferior to that of the original asphalt mixtureBut there are groups with high temperature creep properties superior to the as-received asphalt mix;
in the case of the third situation, the first,
Figure FDA0003647504810000015
and is
Figure FDA0003647504810000016
Namely, the high-temperature creep and low-temperature relaxation performance of any recycled asphalt mixture is inferior to that of the original asphalt mixture;
in the case of the fourth situation,
Figure FDA0003647504810000017
and is
Figure FDA0003647504810000018
I.e. any reclaimed asphalt mixture has a higher high temperature creep performance than the as-received asphalt mixture, but there is a group with a higher low temperature relaxation performance than the as-received asphalt mixture.
3. The method for designing the balance of the high-temperature creep and the low-temperature relaxation performance of the recycled asphalt mixture as claimed in claim 2, wherein the method comprises the following steps: the optimum balance point in step S8 is classified as follows:
if this is the case one, inp/FNi＜εp/FNVAnd t issi＜tsVTaking the minimum value point of the value l as the optimal balance point;
if the case is two, inp/FNi＜εp/FNVUnder the condition of (b), tsiTaking the minimum value point as the optimal balance point;
if the case is three, inp/FNi＞εp/FNVAnd t issi＞tsVTaking the minimum value point of the value l as the optimal balance point;
if the case is four, at tsi＜tsVUnder the condition of (2), epsilonp/FNiAnd taking the minimum value point as the optimal balance point.
4. The method for designing the balance of the high-temperature creep and the low-temperature relaxation performance of the reclaimed asphalt mixture according to any one of claims 1 to 3, wherein the specific process of the step S6 is as follows:
respectively recording creep and relaxation index values of n groups of recycled asphalt mixtures as original sequences { epsilonp/FN1,εp/FN2,…,εp/FNnAnd ts1,ts2,…,tsnAnd (3) adopting a Min-maxirmanization function to carry out standardization operation, as shown in a formula (1), and respectively recording the standardized creep and relaxation index value results as a new sequence { epsilonp/FN1',εp/FN2',…,εp/FNn' } and { ts1',ts2',…,tsn'}；
Figure FDA0003647504810000021
In the formula: x-original sequence { x1,x2,…,xn}；
y-New sequence { y1,y2,…,yn}∈[0,1]And is dimensionless.
5. The method for designing the balance of the high-temperature creep and the low-temperature relaxation performance of the reclaimed asphalt mixture according to claim 4, wherein the method comprises the following steps: the calculation formula of l in step S7 is as follows:
li＝|εp/FNi'-0.5|+|tsi'-0.5| (2)
in the formula: li-sum of distances of group i;
εp/FNi' -normalized values for the i-th set of creep indicators;
tsi' -normalized values for the i-th set of relaxation indicators.
6. The method for designing the high-temperature creep and low-temperature relaxation performance balance of the recycled asphalt mixture according to claim 4, wherein the specific process for preparing n groups of different recycled asphalt mixtures comprises the following steps: on the basis of initial OAC and ORA, the oilstone ratio and the regenerant are respectively increased in proportion to ensure that the oilstone ratio and the regenerant have k groups of different doping amounts, each level of the oilstone ratio and each level of the regenerant are combined in a cross mode and are doped into the mixture once, and finally n groups of different regenerated asphalt mixtures are prepared, wherein n is k multiplied by k, and k is more than or equal to 3.
7. The method for designing the balance of the high-temperature creep and the low-temperature relaxation performance of the recycled asphalt mixture according to claim 4, wherein the creep and relaxation indexes are obtained by the following steps: respectively carrying out high-temperature creep and low-temperature relaxation tests on the original asphalt mixture and the n groups of regenerated asphalt mixtures to obtain creep and relaxation index values epsilon of the original asphalt mixturep/FNVAnd tsVAnd creep and relaxation index values ε of n groups of recycled asphalt mixturesp/FNiAnd tsi。
CN202110304181.7A 2021-03-22 2021-03-22 High-temperature creep and low-temperature relaxation performance balance design method for recycled asphalt mixture Active CN113128026B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN202110304181.7A CN113128026B (en) 2021-03-22 2021-03-22 High-temperature creep and low-temperature relaxation performance balance design method for recycled asphalt mixture

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202110304181.7A CN113128026B (en) 2021-03-22 2021-03-22 High-temperature creep and low-temperature relaxation performance balance design method for recycled asphalt mixture

Publications (2)

Publication Number Publication Date
CN113128026A CN113128026A (en) 2021-07-16
CN113128026B true CN113128026B (en) 2022-06-24

Family

ID=76773673

Family Applications (1)

Application Number Title Priority Date Filing Date
CN202110304181.7A Active CN113128026B (en) 2021-03-22 2021-03-22 High-temperature creep and low-temperature relaxation performance balance design method for recycled asphalt mixture

Country Status (1)

Country Link
CN (1) CN113128026B (en)

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN115015528B (en) * 2022-06-24 2023-12-08 长沙理工大学 Determination method of construction conditions of high-RAP-doped regenerated asphalt concrete

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN105199600A (en) * 2015-10-23 2015-12-30 山东华特知新化工有限公司 Non-cured rubber asphalt waterproof coating as well as preparation method and application thereof
CN105842087A (en) * 2016-03-03 2016-08-10 安阳工学院 Designing and prediction method for converting high-temperature stress relaxation data into creep data
KR101851075B1 (en) * 2016-10-28 2018-04-20 한국수력원자력 주식회사 Reliability improvement method of finite element analysis of the stress relaxation prediction through the metal material heat treatment
CN108694295A (en) * 2018-06-20 2018-10-23 同济大学 Method is determined based on new pitch grade in the RAP mixtures for really mixing and stirring characteristic
CN108846143A (en) * 2018-03-26 2018-11-20 哈尔滨工业大学 A kind of pitch based on integrated data Optimality Criteria is glutinous to play model parameter identification method
WO2019033668A1 (en) * 2017-08-16 2019-02-21 中国石油大学(华东) Method for predicting failure probability of brittle material under high-temperature creep state
CN111272575A (en) * 2020-03-04 2020-06-12 辽宁省交通科学研究院有限责任公司 Method for determining relationship between low-temperature performance of asphalt cement and low-temperature performance of asphalt mixture

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN105199600A (en) * 2015-10-23 2015-12-30 山东华特知新化工有限公司 Non-cured rubber asphalt waterproof coating as well as preparation method and application thereof
CN105842087A (en) * 2016-03-03 2016-08-10 安阳工学院 Designing and prediction method for converting high-temperature stress relaxation data into creep data
KR101851075B1 (en) * 2016-10-28 2018-04-20 한국수력원자력 주식회사 Reliability improvement method of finite element analysis of the stress relaxation prediction through the metal material heat treatment
WO2019033668A1 (en) * 2017-08-16 2019-02-21 中国石油大学(华东) Method for predicting failure probability of brittle material under high-temperature creep state
CN108846143A (en) * 2018-03-26 2018-11-20 哈尔滨工业大学 A kind of pitch based on integrated data Optimality Criteria is glutinous to play model parameter identification method
CN108694295A (en) * 2018-06-20 2018-10-23 同济大学 Method is determined based on new pitch grade in the RAP mixtures for really mixing and stirring characteristic
CN111272575A (en) * 2020-03-04 2020-06-12 辽宁省交通科学研究院有限责任公司 Method for determining relationship between low-temperature performance of asphalt cement and low-temperature performance of asphalt mixture

Non-Patent Citations (2)

* Cited by examiner, † Cited by third party
Title
基于应力松弛试验下的沥青混合料非线性粘弹性模型研究;田小革等;《公路交通科技》;20100815(第08期);第7-11,16页 *
高模量与高黏沥青老化前后动态力学性能研究;韦慧等;《公路交通科技》;20150215(第02期);第13-20页 *

Also Published As

Publication number Publication date
CN113128026A (en) 2021-07-16

Similar Documents

Publication Publication Date Title
Asi Performance evaluation of SUPERPAVE and Marshall asphalt mix designs to suite Jordan climatic and traffic conditions
Goh et al. A simple stepwise method to determine and evaluate the initiation of tertiary flow for asphalt mixtures under dynamic creep test
Paul Evaluation of recycled projects for performance
Dinegdae et al. Mechanics-based top-down fatigue cracking initiation prediction framework for asphalt pavements
CN101532917A (en) Quick load test method for bridge carrying capacity
CN113128026B (en) High-temperature creep and low-temperature relaxation performance balance design method for recycled asphalt mixture
CN105236830B (en) Drainage asphalt mixture mix-ratio designing method based on volumetric parameters
CN101746995A (en) Bituminous mixture proportion design method based on tightest state
CN114004012B (en) Optimization method for reinforced durable road test of vehicle body test yard
Goh et al. Determination of flow number in asphalt mixtures from deformation rate during secondary state
CN103015292A (en) Method for determining optimal asphalt aggregate ratio of asphalt mixture based on pavement performance
Skronka et al. Impact of shear stress levels on validity of MSCR tests
Sivilevicius et al. Dynamics of vehicle loads on the asphalt pavement of European roads which cross Lithuania
Michael et al. Performance of stone matrix asphalt pavements in Maryland
CN107572896B (en) A kind of AC-20 modified asphalt mixture design method based on pavement performance
Souliman et al. Assessment of the extended fatigue life for rubber and polymer modified asphalt mixtures using flexural bending beam fatigue test
CN115536310A (en) Mix proportion design method of recycled asphalt mixture pavement suitable for high-temperature rainy area
Watson et al. Comparison of Superpave and Marshall mix performance in Alabama
CN106938899A (en) A kind of modified asphalt mixture method for designing suitable for different temperature difference area
Mai et al. Sensitivity of flexible pavement thickness to traffic factors in mechanistic-empirical pavement design
Wei et al. Performance Evaluation Model of Urban Road Asphalt Pavement Based on Attribute Hierarchical Model and Entropy Weight Method
El Khatib Development of a performance-based test method for quantification of cracking potential in asphalt pavement materials
CN107798175B (en) Method for evaluating bearing capacity reserve of asphalt pavement in initial design stage
Toth et al. Rheological characterisation of bituminous binder blends for the design of asphalt mixes containing high recycled asphalt content
Zhou et al. Superpave Implementation Phase I: Determining Optimum Binder Content

Legal Events

Date Code Title Description
PB01 Publication
PB01 Publication
SE01 Entry into force of request for substantive examination
SE01 Entry into force of request for substantive examination
GR01 Patent grant
GR01 Patent grant