Method for evaluating and accepting bearing performance of large-gap asphalt mixture pavement
By temporarily laying an interface transition layer on a large-void asphalt mixture pavement and generating a deformation curve, the problem of low load transfer efficiency in traditional testing methods is solved, enabling accurate evaluation and acceptance of pavement bearing capacity.
Patent Information
- Application Number
- CN202610269662.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-03-06
- Publication Date
- 2026-05-15
AI Technical Summary
Traditional load-bearing plate testing methods cannot accurately assess the load-bearing capacity of large-void asphalt mixture pavements because the load cannot form complete contact with the pavement, resulting in low stress transfer efficiency and overestimation of the assessment results.
A temporary interface transition layer is poured on the surface of the road to be tested to form a smooth bearing interface. A load is applied by a falling weight deflectometer to generate a deformation curve. The ratio of theoretical to actual bearing capacity is calculated to determine the bearing performance of the road.
By eliminating the influence of voids, the load-bearing capacity of the road surface can be accurately assessed, the load transfer efficiency loss can be quantified, and non-destructive testing and accurate acceptance can be achieved.
Smart Images
Figure CN122042425A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of load-bearing performance evaluation technology, specifically to a method for evaluating and accepting the load-bearing performance of large-void asphalt mixture pavements. Background Technology
[0002] Large-void asphalt mixture pavements are widely used in road engineering due to their excellent drainage and skid resistance. However, the interconnected large-void structure on their surface leads to significant limitations in traditional load-bearing plate testing methods.
[0003] Specifically, when using rigid bearing plates for field load-bearing capacity testing, the plates cannot form complete contact with the porous pavement, resulting in an actual contact area far smaller than the theoretical value. This incomplete contact leads to highly uneven load distribution, with most of the pressure concentrated at limited aggregate contact points within the plate's coverage area, rather than the ideal state of uniform overall stress. More critically, some of the applied load leaks directly through the surface voids, failing to be effectively transferred to the underlying aggregate skeleton structure, thus reducing stress transfer efficiency. This phenomenon directly results in the pavement structure stress values calculated based on traditional theoretical models being higher than the effective stress acting on the skeleton, making it difficult for existing assessment methods to accurately reflect the true load-bearing characteristics of large-void pavements. Summary of the Invention
[0004] The purpose of this invention is to provide a method for evaluating and accepting the bearing capacity of large-void asphalt mixture pavements, and to solve the following technical problems.
[0005] The objective of this invention can be achieved through the following technical solutions: A method for evaluating and accepting the bearing capacity of large-void asphalt mixture pavement includes the following steps: Step S1: Temporarily pour and solidify a pre-defined interface transition layer on the surface of the road surface to be tested. The interface transition layer completely fills the voids on the surface of the road surface to be tested to form a smooth load-bearing interface. Step S2: Set a load value sequence, which includes several load values; apply load to the interface transition layer through the bearing plate of the falling weight deflectometer, collect the vertical displacement value of the center point of the bearing plate under each load value in real time, generate a first deformation curve, and obtain the theoretical bearing capacity of the road surface to be tested based on the first deformation curve. Step S3: Select adjacent representative areas on the surface of the original large-void pavement without an interface transition layer. Apply load to the adjacent representative areas using the bearing plate of the falling weight deflectometer based on the load value sequence, generate a second deformation curve, and obtain the actual bearing capacity of the pavement under test based on the second deformation curve. Step S4: Obtain the ratio of the theoretical bearing capacity to the actual bearing capacity, denoted as the bearing efficiency ratio, and compare the bearing efficiency ratio with the preset acceptance threshold to determine whether the bearing capacity of the road surface to be tested is qualified.
[0006] As a further aspect of the present invention: the preset area of the interface transition layer is the same as the area of the bearing plate of the falling weight deflectometer, and the interface transition layer can be peeled off after the test is completed.
[0007] As a further aspect of the present invention: the process of setting the load value sequence includes: Obtain the standard value of the design bearing capacity of the pavement to be tested, and preset the bearing capacity range [F] of the pavement to be tested. min F max ], where F min For the set initial load value, F max The maximum load value is set to be 1.5 times the standard value of the design bearing capacity. Within the bearing capacity range, starting from the initial load value, several load values are selected at equal intervals and monotonically increasing to obtain a load value sequence.
[0008] As a further aspect of the present invention: the process of acquiring the vertical displacement value of the center point of the bearing plate includes: When any load value is applied to the interface transition layer according to the preset load value sequence, the moment when no load value is applied is recorded as the start time, and the moment when the load value application ends is recorded as the end time. The start time and the end time constitute the application time period. During the time period, the side image of the falling weight deflectometer is acquired in real time. The side image is divided into several pixels, the center point of each pixel is obtained, and the center point of any pixel is arbitrarily selected as the origin to establish a two-dimensional coordinate system. The side image of the falling weight deflectometer at the start time is acquired and recorded as the start image. The coordinates of the center point of the bearing plate in the two-dimensional coordinate system are obtained on the start image and recorded as the start coordinates. The coordinates of the center point of the bearing plate in each side image are acquired and recorded as the real-time coordinates. The real-time coordinate that is farthest from the start coordinates is selected and recorded as the maximum displacement coordinate. The distance between the start coordinates and the maximum displacement coordinates is obtained and recorded as the vertical displacement value of the center point of the bearing plate.
[0009] As a further aspect of the present invention: the process of generating the first deformation curve includes: A rectangular coordinate system is established with the load value as the abscissa and the vertical displacement value as the ordinate. Each load value and its corresponding vertical displacement value are converted into coordinate points of corresponding positions in the rectangular coordinate system. The coordinate points are connected by a smooth curve, and the curve is recorded as the first deformation curve.
[0010] As a further aspect of the present invention: the process of obtaining the theoretical bearing capacity of the road surface to be tested includes: Obtain the tangent slope between each two adjacent coordinate points on the first deformation curve. When the tangent slope between two adjacent coordinate points P1 and P2 is greater than a preset slope threshold, coordinate point P1 is determined to be a characteristic inflection point, and the load value corresponding to the characteristic inflection point is recorded as the theoretical bearing capacity.
[0011] As a further aspect of the present invention, the process of obtaining the theoretical bearing capacity of the road surface to be tested further includes: If there is no characteristic inflection point on the first deformation curve, a linear regression equation is obtained by fitting all coordinate points using the least squares method; the maximum allowable vertical displacement of the road surface to be tested is obtained, and the maximum allowable vertical displacement is substituted into the linear regression equation to obtain the load value corresponding to the maximum allowable vertical displacement, which is denoted as the theoretical bearing capacity.
[0012] As a further aspect of the present invention: the process of determining whether the bearing capacity of the road surface to be tested is qualified includes: If the load-bearing capacity is greater than or equal to the acceptance threshold, the load-bearing performance of the road surface under test is qualified; if the load-bearing capacity is less than the acceptance threshold, the load-bearing performance of the road surface under test is unqualified.
[0013] The beneficial effects of this invention are: This invention first lays a temporary interface layer in the test area to eliminate the influence of voids, and measures the theoretical bearing capacity that characterizes the true potential of the material skeleton. Then, the same test is carried out on an adjacent original pavement to obtain the actual bearing capacity that reflects the load transfer efficiency of the actual void structure. By conducting comparative tests on the same pavement under two conditions, accurate evaluation is achieved. The ratio of the two conditions directly quantifies the load transfer efficiency loss caused by the void structure, effectively solving the evaluation problem caused by the complex load transfer mechanism of large void asphalt pavement. Attached Figure Description
[0014] The invention will now be further described with reference to the accompanying drawings.
[0015] Figure 1 This is a schematic diagram illustrating the steps of a method for evaluating and accepting the bearing capacity of large-void asphalt mixture pavement according to the present invention. Detailed Implementation
[0016] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.
[0017] Please see Figure 1 As shown, this invention is a method for evaluating and accepting the bearing capacity of large-void asphalt mixture pavements, comprising the following steps: Step S1: Temporarily pour and solidify a pre-defined interface transition layer on the surface of the road surface to be tested. The interface transition layer completely fills the voids on the surface of the road surface to be tested to form a smooth load-bearing interface. In a preferred embodiment of the present invention, the preset area of the interface transition layer is the same as the area of the bearing plate of the falling weight deflectometer, and the interface transition layer can be peeled off after the test is completed. Specifically, the interface transition layer is composed of a two-component fast-setting epoxy resin and fine-grained quartz sand mixed in a mass ratio of 1:2, with a small amount of peelable additive added. This formulation ensures that the mixture has extremely high fluidity and permeability, sufficient to completely fill the surface and shallow interconnected voids under slight pressure. Its curing time can be controlled within 5 to 10 minutes by adjusting the catalyst ratio, forming a hardened layer with sufficient supporting strength (compressive strength not less than 30 MPa). After determining the test points on-site, clean the surface dust using cleaning tools. Take a circular rigid template with the same area as the bearing plate of the falling weight deflectometer and fit it tightly against the area of the road surface to be tested. Pour the pre-mixed interface transition material into the template, allowing it to flow naturally and gently agitate the template to help it fully penetrate the voids. The material level should be slightly higher than the upper edge of the template. When it has initially solidified but not yet fully hardened, use a scraper to remove excess material along the upper edge of the template, thus forming a temporary hardened layer with the same area as the template, a smooth surface, and tight interlocking with the aggregate below. This layer will reach the required strength for testing after curing at ambient temperature for about 15 minutes. During the testing process, the interface transition layer provides a complete and uniform stress surface for the load-bearing plate, completely eliminating the path of load leakage through the voids. After all tests are completed, the hardened layer can be pried up and peeled off from the edge using a special pry bar. Due to the effect of the peeling additive and the fact that the cohesive strength of the material itself is higher than its adhesion strength with asphalt, the peeling process will not damage the original pavement aggregate. After removal, the original large void structure of the pavement and its water permeability and air permeability are completely restored, achieving true non-destructive testing. Step S2: Set a load value sequence, which includes several load values; apply load to the interface transition layer through the bearing plate of the falling weight deflectometer, collect the vertical displacement value of the center point of the bearing plate under each load value in real time, generate a first deformation curve, and obtain the theoretical bearing capacity of the road surface to be tested based on the first deformation curve. Specifically, the bearing plate of the falling weight deflectometer is aligned and placed on the solidified interface transition layer. The falling weight deflectometer releases the falling weights in sequence according to a set sequence to generate corresponding impact loads. During each impact, the side movement process of the bearing plate is captured synchronously by a high-speed high-definition camera. Using image recognition software, a fixed marker point on the geometric center of the bearing plate is selected. Based on the image of the static moment before loading, the vertical pixel displacement of the marker point relative to the reference position at the peak of each impact load is calculated and then accurately converted into the vertical displacement value of the center point of the bearing plate. In a preferred embodiment of the present invention, the process of setting the load value sequence includes: Obtain the standard value of the design bearing capacity of the pavement to be tested, and preset the bearing capacity range [F] of the pavement to be tested. min F max ], where F min For the set initial load value, F max The maximum load value is set to be 1.5 times the standard value of the design bearing capacity. Within the bearing capacity range, starting from the initial load value, several load values are selected at equal intervals and monotonically increasing to obtain a load value sequence. It is worth noting that a reasonable upper limit for the maximum load is set, which can both fully stimulate the potential response of the road surface and prevent overload from causing accidental damage. In a preferred embodiment of the present invention, the process of acquiring the vertical displacement value of the center point of the bearing plate includes: When any load value is applied to the interface transition layer according to the preset load value sequence, the moment when no load value is applied is recorded as the start time, and the moment when the load value application ends is recorded as the end time. The start time and the end time constitute the application time period. During the time period, the side image of the falling weight deflectometer is acquired in real time. The side image is divided into several pixels, the center point of each pixel is obtained, and the center point of one pixel is arbitrarily selected as the origin to establish a two-dimensional coordinate system. The side image of the falling weight deflectometer at the start time is acquired and recorded as the start image. The coordinates of the center point of the bearing plate in the two-dimensional coordinate system are obtained on the start image and recorded as the start coordinates. The coordinates of the center point of the bearing plate in each side image are acquired and recorded as the real-time coordinates. The real-time coordinate that is farthest from the start coordinates is selected and recorded as the maximum displacement coordinate. The distance between the start coordinates and the maximum displacement coordinates is obtained and recorded as the vertical displacement value of the center point of the bearing plate. In a preferred embodiment of the present invention, the process of generating the first deformation curve includes: A rectangular coordinate system is established with the load value as the abscissa and the vertical displacement value as the ordinate. Each load value and its corresponding vertical displacement value are converted into coordinate points of corresponding positions in the rectangular coordinate system. The coordinate points are connected by a smooth curve, and the curve is recorded as the first deformation curve. In a preferred embodiment of the present invention, the process of obtaining the theoretical bearing capacity of the road surface to be tested includes: Obtain the tangent slope between each two adjacent coordinate points on the first deformation curve. When the tangent slope between two adjacent coordinate points P1 and P2 is greater than the preset slope threshold, coordinate point P1 is determined to be a feature inflection point, and the load value corresponding to the feature inflection point is recorded as the theoretical bearing capacity. The process of setting the slope threshold includes setting the slope threshold within the range of [5%F1, 10%F1], where F1 is the load value corresponding to coordinate point P1; The process of obtaining the theoretical bearing capacity of the road surface to be tested also includes: If there are no characteristic inflection points on the first deformation curve, a linear regression fit is performed on all coordinate points based on the least squares method to obtain a linear regression equation; the maximum allowable vertical displacement of the road surface to be tested is obtained, and the maximum allowable vertical displacement is substituted into the linear regression equation to obtain the load value corresponding to the maximum allowable vertical displacement, which is denoted as the theoretical bearing capacity. Specifically, if there is no characteristic inflection point on the first deformation curve, the response of the pavement structure is very ideal after the void effect is eliminated by the temporary interface layer. The increase in load and the increase in displacement are almost proportional, which is represented as a straight line on the curve. Therefore, the yield inflection point in the traditional sense cannot be found. It should be noted that the maximum allowable vertical displacement is a pre-defined engineering standard value; for example, according to design specifications or industry consensus, it is stipulated that the vertical displacement of the center point of the bearing plate shall not exceed 0.5 mm in this type of pavement test. Step S3: Select adjacent representative areas on the surface of the original large-void pavement without an interface transition layer. Apply load to the adjacent representative areas using the bearing plate of the falling weight deflectometer based on the load value sequence, generate a second deformation curve, and obtain the actual bearing capacity of the pavement under test based on the second deformation curve. Specifically, the falling weight deflectometer is moved to a representative original pavement area adjacent to the previous measuring point, where no interface transition layer is set, maintaining its inherent large void surface state with visible pores; ensuring the bearing plate is placed stably and in natural contact with the aggregate protrusions on the pavement surface; the falling weight deflectometer applies impact loads sequentially, and the same high-definition image acquisition and displacement recognition system is used to record the vertical pixel displacement of the center mark point of the bearing plate under the peak load of each level in real time, and the corresponding vertical displacement value is obtained after conversion; since the load is transmitted through a limited number of aggregate contact points and there is leakage, the observed displacement value under the same load is generally greater than the data obtained in step S2; It should be noted that the generation process of the second deformation curve is the same as that of the first deformation curve, and the process of obtaining the actual bearing capacity is the same as that of obtaining the theoretical bearing capacity. Step S4: Obtain the ratio of the theoretical bearing capacity to the actual bearing capacity, denoted as the bearing efficiency ratio, and compare the bearing efficiency ratio with the preset acceptance threshold to determine whether the bearing capacity of the road surface under test is qualified. Specifically, if the load-bearing capacity ratio is Q%, it quantitatively indicates that due to load transfer losses and non-uniform stress concentration caused by surface and shallow interconnected voids, the actual effective load-bearing capacity of this large-void pavement is only Q% of its material skeleton theoretical potential. In a preferred embodiment of the present invention, the process of determining whether the bearing capacity of the road surface to be tested is qualified includes: If the load-bearing capacity is greater than or equal to the acceptance threshold, the load-bearing performance of the road surface under test is qualified; if the load-bearing capacity is less than the acceptance threshold, the load-bearing performance of the road surface under test is unqualified. The process of setting the acceptance threshold includes: The key design parameters of the pavement to be tested are obtained, including the design target porosity and the minimum allowable bearing capacity standard value corresponding to the road grade; a theoretical calculation model of bearing efficiency ratio is established, which characterizes the theoretical loss rate of load transfer efficiency caused by the idealized random void structure under a specific design porosity; based on the minimum allowable bearing capacity standard value and the theoretical loss rate output by the theoretical calculation model, combined with the engineering experience safety factor, a quantified bearing efficiency ratio threshold is determined by calculation as the preset acceptance threshold.
[0018] The foregoing has provided a detailed description of one embodiment of the present invention, but this description is merely a preferred embodiment and should not be construed as limiting the scope of the invention. All equivalent variations and modifications made within the scope of the present invention should still fall within the scope of the present invention.
Claims
1. A method for evaluating and accepting the bearing capacity of large-void asphalt mixture pavements, characterized in that, Includes the following steps: Step S1: Temporarily pour and solidify a pre-defined interface transition layer on the surface of the road surface to be tested. The interface transition layer completely fills the voids on the surface of the road surface to be tested to form a smooth load-bearing interface. Step S2: Set a load value sequence, which includes several load values; apply load to the interface transition layer through the bearing plate of the falling weight deflectometer, collect the vertical displacement value of the center point of the bearing plate under each load value in real time, generate a first deformation curve, and obtain the theoretical bearing capacity of the road surface to be tested based on the first deformation curve. Step S3: Select adjacent representative areas on the surface of the original large-void pavement without an interface transition layer. Apply load to the adjacent representative areas using the bearing plate of the falling weight deflectometer based on the load value sequence, generate a second deformation curve, and obtain the actual bearing capacity of the pavement under test based on the second deformation curve. Step S4: Obtain the ratio of the theoretical bearing capacity to the actual bearing capacity, denoted as the bearing efficiency ratio, and compare the bearing efficiency ratio with the preset acceptance threshold to determine whether the bearing capacity of the road surface to be tested is qualified.
2. The method for evaluating and accepting the bearing capacity of large-void asphalt mixture pavement according to claim 1, characterized in that, In step S1, the preset area of the interface transition layer is the same as the area of the bearing plate of the falling weight deflectometer, and the interface transition layer can be peeled off after the test is completed.
3. The method for evaluating and accepting the bearing capacity of large-void asphalt mixture pavement according to claim 1, characterized in that, In step S2, the process of setting the load value sequence includes: Obtain the standard value of the design bearing capacity of the pavement to be tested, and preset the bearing capacity range [F] of the pavement to be tested. min F max ], where F min For the set initial load value, F max The maximum load value is set to be 1.5 times the standard value of the design bearing capacity. Within the bearing capacity range, starting from the initial load value, several load values are selected at equal intervals and monotonically increasing to obtain a load value sequence.
4. The method for evaluating and accepting the bearing capacity of large-void asphalt mixture pavement according to claim 1, characterized in that, In step S2, the process of acquiring the vertical displacement value of the center point of the bearing plate includes: When any load value is applied to the interface transition layer according to the preset load value sequence, the moment when no load value is applied is recorded as the start time, and the moment when the load value application ends is recorded as the end time. The start time and the end time constitute the application time period. During the time period, the side image of the falling weight deflectometer is acquired in real time. The side image is divided into several pixels, the center point of each pixel is obtained, and the center point of any pixel is arbitrarily selected as the origin to establish a two-dimensional coordinate system. The side image of the falling weight deflectometer at the start time is acquired and recorded as the start image. The coordinates of the center point of the bearing plate in the two-dimensional coordinate system are obtained on the start image and recorded as the start coordinates. The coordinates of the center point of the bearing plate in each side image are acquired and recorded as the real-time coordinates. The real-time coordinate that is farthest from the start coordinates is selected and recorded as the maximum displacement coordinate. The distance between the start coordinates and the maximum displacement coordinates is obtained and recorded as the vertical displacement value of the center point of the bearing plate.
5. The method for evaluating and accepting the bearing capacity of large-void asphalt mixture pavement according to claim 1, characterized in that, In step S2, the process of generating the first deformation curve includes: A rectangular coordinate system is established with the load value as the abscissa and the vertical displacement value as the ordinate. Each load value and its corresponding vertical displacement value are converted into coordinate points of corresponding positions in the rectangular coordinate system. The coordinate points are connected by a smooth curve, and the curve is recorded as the first deformation curve.
6. The method for evaluating and accepting the bearing capacity of large-void asphalt mixture pavement according to claim 1, characterized in that, In step S2, the process of obtaining the theoretical bearing capacity of the road surface to be tested includes: Obtain the tangent slope between each two adjacent coordinate points on the first deformation curve. When the tangent slope between two adjacent coordinate points P1 and P2 is greater than a preset slope threshold, coordinate point P1 is determined to be a characteristic inflection point, and the load value corresponding to the characteristic inflection point is recorded as the theoretical bearing capacity.
7. The method for evaluating and accepting the bearing capacity of large-void asphalt mixture pavement according to claim 6, characterized in that, In step S2, the process of obtaining the theoretical bearing capacity of the road surface to be tested further includes: If there is no characteristic inflection point on the first deformation curve, a linear regression equation is obtained by fitting all coordinate points using the least squares method; the maximum allowable vertical displacement of the road surface to be tested is obtained, and the maximum allowable vertical displacement is substituted into the linear regression equation to obtain the load value corresponding to the maximum allowable vertical displacement, which is denoted as the theoretical bearing capacity.
8. The method for evaluating and accepting the bearing capacity of large-void asphalt mixture pavement according to claim 1, characterized in that, Step S4, the process of determining whether the bearing capacity of the road surface to be tested is qualified includes: If the load-bearing capacity is greater than or equal to the acceptance threshold, the load-bearing performance of the road surface under test is qualified; if the load-bearing capacity is less than the acceptance threshold, the load-bearing performance of the road surface under test is unqualified.