CN-121994644-A - Asphalt pavement density estimation method based on L-R dielectric mixing theory

CN121994644ACN 121994644 ACN121994644 ACN 121994644ACN-121994644-A

Abstract

The invention provides an asphalt pavement density estimation method based on an L-R dielectric mixing theory, which relates to the technical field of road engineering nondestructive testing and comprises the following steps of S1, establishing an asphalt mixture density estimation model based on the L-R dielectric mixing theory, determining a geometric arrangement coefficient c as a model key optimization parameter, S2, obtaining relative dielectric constant data of asphalt, mineral aggregate and asphalt mixture and volume, quality and density actual measurement data of the asphalt mixture, S3, solving an optimal value of the geometric arrangement coefficient c by taking an average relative error of asphalt mixture density estimation as an objective function, and establishing a density estimation optimization model based on the optimal value, and S4, adopting laboratory different asphalt mixture test piece data and field pavement core sample data to verify the density estimation precision of the density estimation optimization model. The invention is suitable for various asphalt mixtures, has simple form and high calculation efficiency, and realizes real-time high-precision nondestructive detection of the compactness of the asphalt pavement.

Inventors

ZENG SIQING
LIU GANG
YANG MING
CHEN BO
CAI MIN
LI WEIXIONG
SUN WENJIN
LUO JING
ZHANG JINGBO
CHEN CHULONG
ZHUANG JIAFENG

Assignees

广东省公路建设有限公司
华南理工大学
中交第二公路勘察设计研究院有限公司

Dates

Publication Date: 20260508
Application Date: 20260127

Claims (10)

1. An asphalt pavement density estimation method based on an L-R dielectric mixing theory is characterized by comprising the following steps: s1, establishing an asphalt mixture density estimation model general type based on an L-R dielectric mixing theory, and determining a geometric arrangement coefficient c as a key optimization parameter of the model; S2, acquiring relative dielectric constant data of asphalt, mineral aggregate and asphalt mixture, and volume, mass and density actual measurement data of the asphalt mixture; S3, solving an optimal value of the geometric arrangement coefficient c by taking an average relative error of asphalt mixture density estimation as an objective function, and establishing a density estimation optimization model based on the optimal value; And S4, verifying the density estimation precision of the density estimation optimization model by adopting laboratory different asphalt mixture test piece data and field pavement core sample data.
2. The method according to claim 1, wherein the core equation of the L-R dielectric hybrid theory in step S1 follows the power law by the expression: Formula (1): Wherein epsilon m is the dielectric constant of the asphalt mixture, epsilon i is the dielectric constant of the component i in the asphalt mixture, V i is the volume ratio of the component i, and c is the geometric arrangement coefficient.
3. The method according to claim 2, wherein the asphalt mixture in step S1 is regarded as a three-phase heterogeneous mixture composed of asphalt, mineral aggregate and void air, and the general expression of the asphalt mixture dielectric mixing model established based on the L-R dielectric mixing theory is: formula (2): Wherein V a 、V b 、V se is the volume ratio of the air in the gap, the asphalt and the mineral aggregate, and epsilon a 、ε b 、ε s is the relative dielectric constants of the air in the gap, the asphalt and the mineral aggregate.
4. A method according to claim 3, wherein when setting asphalt mix Mao Tiji V T = 1, the volume fractions of the components are calculated by the following formula: formula (3): formula (4): formula (5): Wherein G mb is the volume relative density of asphalt mixture, G mm is the maximum theoretical relative density of asphalt mixture, P b is the asphalt content, G b is the relative density of asphalt, and G se is the effective relative density of mineral aggregate.
5. The method of claim 4, wherein the general formula of the density estimation model in step S1 is obtained by substituting formulas (3) - (5) into formula (2), and the relative dielectric constant epsilon a = 1 of the air in the air gap is expressed as: formula (6): 。
6. The method according to claim 5, wherein the geometric arrangement coefficient c in step S3 has a value ranging from a closed interval [ -1,1], and the average relative error of the density estimation is calculated by traversing all c values in the interval of 0.1 and substituting the values into the density estimation model generic formula, and when the average relative error is minimum, the corresponding c value is the optimal value of 0.3.
7. The method of claim 6, wherein the GAO model in step S3 is obtained by substituting the optimal geometric arrangement coefficient c=0.3 into formula (6), where the formula is: Formula (7): 。
8. The method according to claim 1, wherein the relative dielectric constant is measured by a dielectric constant tester in the step S2, the measuring object comprises asphalt, mineral aggregate and an asphalt mixture test piece, wherein the asphalt mixture test piece is prepared into a cylinder with a diameter of 100mm x a height of 84mm, a standard test piece with a height of 70mm is obtained after cutting 7mm at each end, the relative dielectric constant of the test piece is measured 5 times at different directions on the top surface and the bottom surface of the test piece, and the average value is taken as the relative dielectric constant of the test piece, and the density data is measured by a surface dry method.
9. The method according to claim 1, wherein the data in step S2 constitute a diverse data set comprising data related to asphalt mixtures of AC type, OGFC type, SMA type and AM type, the number of effective samples being not less than 34 groups.
10. The method according to claim 1, wherein the model verification in the step S4 comprises laboratory verification and field verification, the laboratory verification adopts different types of asphalt mixture test piece data, the field verification adopts field drilled pavement core sample data, the verification index comprises a fitting goodness R2 and an average relative error, the fitting goodness R2 of the GAO model is more than or equal to 0.91, and the average relative error is less than or equal to 1.83%.

Description

Asphalt pavement density estimation method based on L-R dielectric mixing theory Technical Field The invention relates to the technical field of road engineering nondestructive testing, in particular to an asphalt pavement density prediction method based on an L-R dielectric mixing theory, which is suitable for real-time and high-precision nondestructive testing and evaluation of compaction quality of asphalt mixtures. Background The compactness is a core index for controlling the construction quality of the asphalt pavement, and the service life of the pavement is directly influenced by the value of the compactness, namely, the pavement is easy to crack due to the fact that the compactness is too high, and diseases such as rutting, water damage and the like are easy to be caused due to the fact that the compactness is too low, so that the maintenance cost is greatly increased. The traditional asphalt pavement density detection depends on a core drilling sampling method, and the method has the defects of accurate measurement, destructive property, low efficiency, poor sample representativeness and the like, and cannot meet the requirements of modern engineering on efficient, continuous and nondestructive detection. In order to solve the problems, dielectric property-based nondestructive testing techniques such as Ground penetrating radar group PENETRATING RADAR GPR for short and coreless densitometer are widely used, and the core is to build an accurate relation model of the dielectric constant and density of the asphalt mixture. The existing density estimation models mainly comprise a statistical regression model based on a small number of samples and poor universality, and a theoretical model based on an electromagnetic mixing theory, such as a CRIM model, namely a complex refractive index model, a Rayleigh model, namely a Rayleigh Lei Moxing model, a Bottcher model, namely a Bottcher model and the like, wherein the models are mostly based on idealized assumptions, such as spherical component particles and uniform medium, and are difficult to accurately describe dielectric behaviors of asphalt mixture three phases, namely asphalt, mineral aggregates and a void non-uniform structure. LICHTENECKER-Rother, i.e., L-R dielectric hybrid theory, provides a more general framework that characterizes the spatial arrangement and polarization state of components by geometric arrangement coefficient Geometric Arrangement Factor, simply c, with CRIM model c=0.5, brown model c=1, etc. being specific examples. However, when the L-R theory is applied to the asphalt mixture in the prior art, the value of the geometric arrangement coefficient c depends on experience or a continuous fixed value, the influence of actual characteristics such as the grading of the asphalt mixture, the aggregate morphology and the like is not considered, so that the model prediction precision is insufficient, meanwhile, the relative dielectric constants of asphalt and mineral aggregates in the traditional model adopt fixed experience values, material variability errors are ignored, and a unified high-precision model suitable for various asphalt mixtures such as AC, SMA, AM and the like is lacking, so that the universality is poor. Disclosure of Invention The invention aims to provide an asphalt pavement density estimation method based on an L-R dielectric mixing theory, which aims to solve the technical defects pointed out in the background art. In order to solve the technical problems, the invention adopts the following technical scheme: an asphalt pavement density estimating method based on an L-R dielectric mixing theory comprises the following steps: s1, establishing an asphalt mixture density estimation model general type based on an L-R dielectric mixing theory, and determining a geometric arrangement coefficient c as a key optimization parameter of the model; S2, acquiring relative dielectric constant data of asphalt, mineral aggregate and asphalt mixture, and volume, mass and density actual measurement data of the asphalt mixture; S3, solving an optimal value of the geometric arrangement coefficient c by taking an average relative error of asphalt mixture density estimation as an objective function, and establishing a density estimation optimization model based on the optimal value; And S4, verifying the density estimation precision of the density estimation optimization model by adopting laboratory different asphalt mixture test piece data and field pavement core sample data. Further as an improvement of the technical scheme of the invention, the core equation of the L-R dielectric mixing theory in the step S1 follows the law of power law, and the expression is: Formula (1): Wherein epsilon m is the dielectric constant of the asphalt mixture, epsilon i is the dielectric constant of the component i in the asphalt mixture, V i is the volume ratio of the component i, and c is the geometric arrangement coefficient. Further as an improvement