CN-121998504-A - Cold region high-grade highway regenerated asphalt pavement structure optimization method

CN121998504ACN 121998504 ACN121998504 ACN 121998504ACN-121998504-A

Abstract

The invention relates to the technical field of road engineering and discloses a cold region high-grade highway regenerated asphalt pavement structure optimization method which comprises the steps of constructing an evaluation index system, checking fatigue cracking life, permanent deformation and low-temperature cracking resistance in advance, determining subjective weights of all evaluation indexes based on row-column summation relation optimization of a preliminary matrix and a square root method when a preset threshold requirement is met, determining objective weights of all evaluation indexes according to a decision matrix and a risk correction coefficient, dynamically determining a weight fusion coefficient based on a cold region risk sensitivity index, calculating the cold region risk sensitivity index according to an extreme low-temperature coefficient and a freeze thawing cycle coefficient, determining comprehensive weights of all evaluation indexes by adopting a comprehensive weighting method, calculating relative closeness of all regenerated pavement structure schemes, and sequencing schemes according to the relative closeness to determine an optimal regenerated pavement structure scheme. The invention can accurately screen the optimal regenerated pavement structure suitable for the cold region.

Inventors

Ding longting
Ji Xiaoge
YANG YAOHUI
LI LI
ZHANG LE
ZHANG MENGYUAN
LI HAO
CONG BORI
ZHANG JIZHE
ZHAO QUANMAN
Shang Hongfa
YANG RUI

Assignees

山东高速集团有限公司
山东建筑大学
山东高速集团有限公司创新研究院

Dates

Publication Date: 20260508
Application Date: 20260127

Claims (10)

1. A preferred method for a cold-zone high-grade highway recycled asphalt pavement structure, which is characterized by comprising the following steps: Constructing an evaluation index system, wherein the evaluation index system comprises a mechanical response index, a structure checking index, a low-temperature adaptability index and an economical index, wherein the mechanical response index comprises an asphalt layer bottom tensile strain, a base layer bottom tensile stress, an old road top vertical compressive strain and a regeneration layer bottom tensile strain, the structure checking index comprises a fatigue cracking life and a permanent deformation amount, the low-temperature adaptability index comprises a low-temperature cracking resistance, and the economical index comprises a structure cost; checking the fatigue cracking life, the permanent deformation and the low-temperature cracking resistance in advance, and judging whether each index meets the preset threshold requirement; When the fatigue cracking life, the permanent deformation and the low-temperature crack resistance all meet the preset threshold requirements, determining subjective weights of all evaluation indexes based on row-column summation relation optimization of a preliminary matrix and a method of a root, and determining objective weights of all evaluation indexes according to a decision matrix and a risk correction coefficient; Dynamically determining a weight fusion coefficient based on a cold region risk sensitivity index, wherein the cold region risk sensitivity index is calculated according to an extreme low temperature coefficient and a freeze thawing cycle coefficient; Determining the comprehensive weight of each evaluation index by adopting a comprehensive weighting method according to the weight fusion coefficient, the subjective weight and the objective weight; establishing an evaluation matrix, calculating the relative closeness of each regenerated pavement structure scheme based on the comprehensive weight, and sequencing the schemes according to the relative closeness to determine the optimal regenerated pavement structure scheme.
2. The method for optimizing a structure of a cold zone high grade highway recycled asphalt pavement according to claim 1, wherein the pre-checking of fatigue crack life, permanent deformation and low temperature crack resistance comprises: judging whether the fatigue cracking life meets the accumulated axle load requirement or not; judging whether the permanent deformation is smaller than or equal to a preset permanent deformation threshold value; Judging whether the low-temperature cracking index corresponding to the low-temperature cracking resistance is smaller than or equal to a preset cracking index threshold value; and if any index of the fatigue cracking life, the permanent deformation and the low-temperature crack resistance does not meet the corresponding threshold requirement, judging that the regenerated pavement structural scheme is not qualified.
3. The method for optimizing a structure of a renewable asphalt pavement of a highway in a cold area according to claim 1, wherein the determining subjective weights of the evaluation indexes based on the optimization of the row-column summation relation of the preliminary matrix and the method of the root method comprises: The establishment principle of the preliminary matrix comprises the steps of assigning a preset important value if the current index is more important than the next index, assigning a preset equal value if the current index is equal to the next index, and assigning a preset secondary value if the current index is not important; According to the temperature sensitivity characteristics of the regenerated pavement material in severe cold areas, adjusting importance assignment of the tensile strain of the bottom of the regenerated layer relative to the tensile strain of the bottom of the asphalt layer in the preliminary matrix; Carrying out cold region risk coefficient calibration on the primary matrix based on the climate zone type of the place where the project is located, and obtaining a calibrated primary matrix; And optimizing the calibrated preliminary matrix according to a row-column summation relationship to obtain an improved matrix, and calculating subjective weights of all evaluation indexes based on the improved matrix by using a square root method.
4. A preferred method for constructing a renewable asphalt pavement of a highway in a cold area according to claim 3, wherein said calibrating the risk coefficient of the preliminary matrix based on the type of the climate zone in which the project is located comprises: Determining that the place where the project is located belongs to an extremely cold region, a severe cold region or a cold region; when the place where the project is located belongs to an extremely cold region, increasing the assignment weight of the low-temperature crack resistance by a first preset proportion; When the place where the project is located belongs to a severe cold region, increasing the assigned weight of the low-temperature crack resistance by a second preset proportion; When the place where the project is located belongs to a cold area, increasing the assignment weight of the low-temperature crack resistance by a third preset proportion, wherein the first preset proportion is larger than the second preset proportion, and the second preset proportion is larger than the third preset proportion; And (3) performing matrix normalization processing on the lifted assigned weights to ensure the reasonability of the assigned weights of the low-temperature cracking resistance.
5. A preferred method for constructing a cold-zone high-grade highway recycled asphalt pavement according to claim 3, wherein said optimizing the calibrated preliminary matrix according to a row-column summation relationship comprises: calculating the sum of all elements of each row in the calibrated preliminary matrix; Calculating the sum of all elements in each column of the calibrated preliminary matrix; Comparing the size relation between the sum of all elements of the current row and the sum of all elements of the current column in the calibrated preliminary matrix; If the sum of all elements in the current row is greater than or equal to the sum of all elements in the current column, adding a preset unit value after making a difference between the sum of all elements in the current row and the sum of all elements in the current column, and obtaining an element value at a corresponding position in the improved matrix; if the sum of all elements in the current row is smaller than the sum of all elements in the current column, adding a preset unit value after making a difference between the sum of all elements in the current row and the sum of all elements in the current column, and then taking the reciprocal of the result to obtain an element value at a corresponding position in the improved matrix; the expression of the element value of the corresponding position in the improvement matrix is: ; ; in the formula, To improve the first in the matrix Line 1 Element values of columns; and the first of the calibrated preliminary matrix Row sum of all elements; to the first of the calibrated preliminary matrix The sum of all elements is listed.
6. The method for optimizing a structure of a cold-zone high-grade highway recycled asphalt pavement according to claim 1, wherein determining objective weights of the evaluation indexes according to the decision matrix and the risk correction coefficient comprises: constructing a decision matrix according to the original index data of each regenerated pavement structure scheme, and carrying out standardization processing on the decision matrix; carrying out normalization processing on the normalized decision matrix; Determining risk correction coefficients corresponding to all evaluation indexes according to the association degree of the evaluation indexes and the severe cold risk, wherein the risk correction coefficients corresponding to the low-temperature crack resistance are gradually decreased in extremely cold areas, severe cold areas and cold areas, and the risk correction coefficients corresponding to the tensile strain of the regenerative layer bottoms are gradually decreased in extremely cold areas, severe cold areas and cold areas; multiplying the elements of the decision matrix after normalization processing with risk correction coefficients corresponding to the evaluation indexes to obtain a corrected decision matrix; calculating corrected information entropy based on the corrected decision matrix, and calculating objective weights of all evaluation indexes according to the corrected information entropy; the expression for calculating the objective weight of each evaluation index according to the corrected information entropy is as follows: ; in the formula, Is the first Objective weights of the individual evaluation indexes; Is the first Corrected information entropy of each evaluation index; the total number of the evaluation indexes.
7. The method for optimizing a cold zone high grade highway recycled asphalt pavement structure according to claim 1, wherein dynamically determining the weight fusion coefficient based on the cold zone risk sensitivity index comprises: determining an extreme low temperature coefficient according to the lowest air temperature of the place where the project is located within a near preset period so as to reflect the damage strength of the low temperature to the pavement; Determining a freeze-thawing cycle coefficient according to the annual freeze-thawing cycle times of the project location so as to reflect the damage degree of freeze thawing to the regeneration layer; calculating a cold region risk sensitivity index by using the extremely low temperature coefficient and the freeze-thawing cycle coefficient; Based on the risk sensitivity index of the cold region, a nonlinear function is adopted to calculate a weight fusion coefficient, and verification and constraint of dynamic adjustment are carried out on the weight fusion coefficient.
8. The method for optimizing a structure of a cold zone high grade highway recycled asphalt pavement according to claim 7, wherein calculating a cold zone risk sensitivity index using an extreme low temperature coefficient and a freeze-thaw cycle coefficient comprises: multiplying the extremely low temperature coefficient by a first preset weight to obtain a first weight value; Multiplying the freeze-thawing cycle coefficient with a second preset weight to obtain a second weight value; Adding the first weighted value and the second weighted value to obtain a cold region risk sensitivity index; The expression for calculating the weight fusion coefficient by adopting the nonlinear function is as follows: ; in the formula, Is a weight fusion coefficient; is a risk sensitivity index for cold regions.
9. The method for optimizing a structure of a cold zone high-grade highway recycled asphalt pavement according to claim 7, wherein calculating the weight fusion coefficient using a nonlinear function based on the cold zone risk sensitivity index comprises: subtracting a preset reference value from the risk sensitivity index of the cold region to obtain a risk offset; Taking a negative value of the risk offset as an index, and calculating the exponent power of a natural logarithmic base to obtain an exponential decay value; subtracting the exponential decay value from a preset unit value to obtain an adjustment amplitude; Multiplying the adjustment amplitude by a preset fluctuation coefficient to obtain a weight increment; Adding the weight increment and a preset basic weight to obtain the weight fusion coefficient; The weight fusion coefficient meets the range from the preset lower limit value to the preset upper limit value.
10. The method for optimizing a structure of a renewable asphalt pavement of a highway in a cold area according to claim 1, wherein said establishing an evaluation matrix and calculating the relative closeness of each renewable pavement structure scheme based on the comprehensive weight comprises: establishing a related evaluation matrix according to the original index data of each regenerated pavement structure scheme; After carrying out normalization processing on the related evaluation matrix, establishing a canonical matrix considering the combined weight by combining the comprehensive weights of all evaluation indexes; Determining an optimal value vector and a worst value vector according to the canonical matrix; Calculating Euclidean distance between each regenerated pavement structure scheme and the optimal value vector, and calculating Euclidean distance between each regenerated pavement structure scheme and the worst value vector; taking the Euclidean distance between each regenerated pavement structure scheme and the optimal value vector and the Euclidean distance between each regenerated pavement structure scheme and the optimal value vector as denominators; dividing the numerator by a denominator to obtain the relative closeness of each regenerated pavement structure scheme; the value range of the relative closeness is from a preset minimum value to a preset maximum value, and the larger the value is, the better the evaluation object is represented.

Description

Cold region high-grade highway regenerated asphalt pavement structure optimization method Technical Field The invention relates to the technical field of road engineering, in particular to a cold region high-grade highway regenerated asphalt pavement structure optimization method. Background In the long-term use and maintenance process of road traffic infrastructure, asphalt pavement is widely adopted due to good road performance, but with the increase of service life, the problems of fatigue cracking, low-temperature cracking, permanent deformation, bearing capacity reduction and the like are easy to occur, and the pavement function needs to be recovered by reconstruction and expansion or re-paving. In the process, a large amount of waste asphalt mixture (RAP) is generated, if the RAP is randomly stacked, not only the land resources are occupied and the environment is polluted, but also the high-quality aggregate and asphalt components in the RAP are wasted, which runs counter to the development concept of resource conservation and low carbon environment protection, so that the asphalt pavement regeneration technology has become an important research direction of the industry. Particularly in severe cold areas, the temperature in winter can be as low as minus 20 ℃, and heavy-duty vehicles frequently pass, and special climates and load conditions provide higher requirements for the structural performance of the regenerated pavement, but the existing regenerated pavement technology is difficult to meet the actual engineering requirements, and has a plurality of problems to be solved urgently. Most of the prior regenerated pavement structural designs refer to experience of normal temperature areas, the difference of climates in cold areas is not fully considered, namely, extreme conditions such as extremely cold are often caused besides the difference among areas, and the fatigue problem of a regenerated layer is not specifically considered. In the prior art, the mechanical analysis of the regenerated pavement often ignores key indexes such as tensile strain of the bottom of a regenerated layer and cracking index based on a low-temperature reproduction period, and only pays attention to conventional parameters such as tensile strain of the bottom of an asphalt layer and tensile stress of the bottom of a base layer, so that a designed structure is easy to crack due to the accumulation of fatigue damage of the regenerated layer in actual use or low-temperature cracking is caused by the fact that Wen Jizhi exceeds design expectations. Meanwhile, the traditional design does not have the temperature sensitivity of the regenerated mixture in a systematic quantification way, namely the modulus of the regenerated mixture is obviously influenced by temperature, and the strain response rule of the regenerated layer under different axial loads within the working temperature range of-20 ℃ to 40 ℃ is not clear, so that the stability of the whole life cycle of the structure is difficult to ensure. For example, after part of old roads (the original structure is a 3cm upper layer, a 4cm lower layer and a 20cm base layer) run for many years, the deflection value is mostly more than 20 (0.01 mm), the serious road section is even more than 30 (0.01 mm), a large number of transverse cracks, partial longitudinal cracks and partial blocky damages exist, and the bearing capacity and the crack resistance of the road surface are seriously insufficient. In the aspect of the structural optimization of the regenerated pavement, the existing evaluation system has the problems of incomplete indexes and unreasonable weight determination method. The conventional evaluation does not construct a comprehensive index system comprising mechanical response, structure checking calculation, low-temperature adaptability and economy, and is easy to pay attention to only single performance and neglect overall matching. In weight determination, the traditional analytic hierarchy process has a plurality of iteration times, results are easily influenced by human factors, a simple entropy weight process is excessively dependent on sample data and subjective experience information is easily lost, and information loss exists in both methods, so that subjective and objective information cannot be effectively fused. In the prior art, after various regenerated pavement structure schemes are drawn up, a system screening process based on multidimensional indexes is also lacking, subjective judgment is often carried out by experience, and performance differences of different schemes under weather and load conditions in cold regions cannot be quantified, so that an evaluation result is disjointed from an engineering actual condition, and an optimal regenerated pavement structure suitable for the cold regions is difficult to accurately screen. For the problems in the related art, no effective solution has been proposed at present. Disclosure of Invention Aiming at