Method for evaluating temperature segregation degree of asphalt mixture during pavement paving

Abstract

The invention discloses a method for evaluating the temperature segregation degree of an asphalt mixture during pavement paving, and the method comprises the following steps: 1, scanning the asphalt mixture paved on a lane through a thermal infrared imager, and obtaining the temperature value of each point in a target region; step 2, eliminating temperature data without representativeness in the target area; and 3, combining the normal construction temperature range of the asphalt mixture with the temperature interval standard of temperature segregation of the asphalt mixture. According to the method, the temperature of the asphalt pavement during paving is detected by utilizing infrared thermal imaging, data without representativeness in the temperature data is removed by combining a post-processing algorithm for the temperature data, and the temperature segregation degree of the mixture during paving of the asphalt pavement is accurately and comprehensively evaluated; and the paving temperature uniformity condition can be fed back to construction management personnel in time in the construction process, so that the construction management personnel can better master the temperature condition of a mixture during pavement construction.

Description

Technical Field

[0001] The present invention relates to a technical field, and in particular to a method for evaluating the degree of temperature segregation of asphalt mixture during road paving. Background Art

[0002] Asphalt mixture is a temperature-sensitive material, and its performance is closely related to temperature. Temperature changes will definitely affect the performance of asphalt mixture. Therefore, the temperature uniformity during asphalt pavement paving will directly affect the compaction and durability of asphalt pavement. According to a project research report by the US National Transportation Board (TRB), severe temperature segregation will reduce the service life of asphalt pavement by more than 50%. The paving temperature uniformity of asphalt mixture plays an important role in the performance of asphalt pavement.

[0003] For temperature detection during asphalt pavement paving, the traditional measurement method mainly uses infrared temperature recorders and insertion thermometers with metal probes (Chinese patents CN102691251B, CN102691251A, CN116929598A). However, the traditional "point-to-surface" temperature detection method cannot actually reflect the construction quality of the asphalt pavement, nor can it effectively monitor abnormal temperature changes, and cannot make an overall evaluation of the temperature uniformity of the paved pavement.

[0004] This method uses infrared thermal imaging to detect the temperature of the asphalt pavement during paving, and combines it with a post-processing algorithm for the temperature data to eliminate unrepresentative data in the temperature data, so as to more accurately and comprehensively evaluate the degree of temperature segregation of the mixture during asphalt pavement paving. It can provide timely feedback on the paving temperature uniformity to construction management personnel during the construction process, which helps construction management personnel to better understand the temperature conditions of the mixture during pavement construction. Summary of the invention

[0005] The purpose of this section is to summarize some aspects of embodiments of the present invention and briefly introduce some preferred embodiments. Some simplifications or omissions may be made in this section and the specification abstract and the invention title of this application to avoid blurring the purpose of this section, the specification abstract and the invention title, and such simplifications or omissions cannot be used to limit the scope of the present invention.

[0006] In view of the problems existing in the above-mentioned existing method for evaluating the degree of temperature segregation of asphalt mixture during road paving, the present invention is proposed.

[0007] Therefore, the purpose of the present invention is to provide an evaluation method for the degree of temperature segregation of asphalt mixture during pavement paving, which can collect the temperature in the plane of the paver working section in real time online, and can truly and comprehensively reflect the temperature distribution of the asphalt mixture in the construction section. An indicator characterizing the degree of temperature segregation of the asphalt mixture in the construction section is proposed, and the degree of temperature segregation of the asphalt mixture in different construction sections can be quantitatively compared.

[0008] In order to solve the above technical problems, the present invention provides the following technical solution: a method for evaluating the degree of temperature segregation of asphalt mixture during pavement paving, comprising the following steps:

[0009] Step 1: Use an infrared thermal imager to scan the asphalt mixture spread on the lane to obtain the temperature value of each point in the target area;

[0010] Step 2: Eliminate unrepresentative temperature data in the target area;

[0011] Step 3: Combine the normal construction temperature range of asphalt mixture and the temperature range standard of asphalt mixture temperature segregation, and classify the remaining data according to the temperature range;

[0012] Step 4: For each type of classified data, add up their respective quantities with a certain weight to obtain the temperature segregation degree of the target area, and make an overall quantitative evaluation of the temperature segregation degree in the target area.

[0013] As a preferred scheme of the method for evaluating the degree of temperature segregation of asphalt mixture during pavement paving described in the present invention, wherein: in the step one, the field of view angle range of the infrared thermal imager is adjusted in combination with the size of the target area, and the camera is photographed after focusing to obtain an infrared image.

[0014] As a preferred solution of the method for evaluating the degree of temperature segregation of asphalt mixture during pavement paving of the present invention, wherein: in the step 1, the infrared thermal image taken on site is imported into the infrared image analysis software for processing, the temperature measurement distance, relative humidity, emissivity and reflection temperature are set according to the actual situation of the construction site, and blue and red are selected to represent the lower and higher areas of the road surface temperature respectively; the target area is selected, the length L and width W of the road surface behind the paver on the construction site where the temperature data needs to be collected are determined, and a point is taken at a distance a along the longitudinal and transverse directions of the lane, and n points are taken on the target area to obtain the temperature value t of each point in the target area. x,y , where x and y represent the x-coordinate and y-coordinate of the location of the unit, respectively. n temperature data are obtained, and the longitudinal direction of the lane is the x-axis, with a total of n x points; along the lane horizontally is the y-axis, there are n points in total y points; n = n x ×n y , unit: m.

[0015] As a preferred embodiment of the method for evaluating the degree of temperature segregation of asphalt mixture during pavement paving of the present invention, the elimination method in step 2 includes: for any unit temperature value t x,y , take the average temperature value Eva of all units within a certain area around it x,y , the x-coordinate range of the area is [xa,x+a], the y-coordinate range is [y-1.25,y+1.25], x∈[2a,n x -a],y∈[1.25+a,n y -1.25], unit: m;

[0016] Among them, if Eva x,y <160℃, then remove t x,y , otherwise keep t x,y , and finally the remaining n r Temperature data.

[0017] As a preferred scheme of the method for evaluating the degree of temperature segregation of asphalt mixture during pavement paving according to the present invention, wherein: in the step three, the density and porosity changes of the asphalt mixture under different temperature change ranges are compared: when the temperature changes from 0 to 10°C, the temperature interval is defined as the no temperature segregation interval T0; when the temperature changes from 10 to x1°C, the temperature interval is defined as the mild temperature segregation interval T1; when the temperature changes from x1 to x2°C, the temperature interval is defined as the moderate temperature segregation interval T2; when the temperature changes from x2 to x3°C, the temperature interval is defined as the severe temperature segregation interval T3; the four temperature intervals T0, T1, T2 and T3 correspond to the sets c0, c1, c2 and c3, respectively.

[0018] As a preferred embodiment of the method for evaluating the degree of temperature segregation of asphalt mixture during pavement paving of the present invention, the classification method in step 3 is as follows: a data a1 is selected from set C, and the remaining data is a i , i = 1, 2, 3…n, compare data a1 with other data a in set C i Take the absolute value of the difference d i , i=1,2,3…n; select d in the temperature intervals T0, T1, T2 and T3 i The interval in which it is located is stored in the set c0, c1, c2 or c3 corresponding to the interval. Finally, the number of elements in the four sets c0, c1, c2 and c3 are count_c0, count_c1, count_c2 and count_c3 respectively.

[0019] As a preferred embodiment of the method for evaluating the degree of temperature segregation of asphalt mixture during pavement paving of the present invention, in which: in the step 4, count_c0, count_c1, count_c2 and count_c3 are weighted averaged, and the weights are 0, and The index representing the degree of temperature segregation in the construction section is obtained:

[0020]

[0021] The beneficial effects of the present invention are as follows: the present invention collects the temperature in the plane of the paver operation section in real time online, can truly and comprehensively reflect the temperature distribution of the asphalt mixture in the construction section, proposes an index to characterize the degree of temperature segregation of the asphalt mixture in the construction section, and can quantitatively compare the degree of temperature segregation of the asphalt mixture in different construction sections; the method is used to evaluate the degree of segregation of the asphalt mixture during asphalt pavement paving, and has the advantages of simple operation, low cost and strong characterization; the method can effectively improve the management level and construction quality of road engineering construction, and has good market prospects and economic benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative labor. Among them:

[0023] Figure 1 It is a logical framework diagram of the method for evaluating the degree of temperature segregation of asphalt mixture during pavement paving according to the present invention.

[0024] Figure 2 It is a schematic diagram of a specific process of the method for evaluating the degree of temperature segregation of asphalt mixture during pavement paving according to the present invention.

[0025] Figure 3 It is an infrared thermal image of the on-site construction of asphalt pavement paving, which shows the degree of temperature segregation of asphalt mixture during pavement paving of the present invention. DETAILED DESCRIPTION

[0026] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are described in detail below in conjunction with the accompanying drawings.

[0027] In the following description, many specific details are set forth to facilitate a full understanding of the present invention, but the present invention may also be implemented in other ways different from those described herein, and those skilled in the art may make similar generalizations without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0028] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The term "in one embodiment" that appears in different places in this specification does not necessarily refer to the same embodiment, nor does it refer to a separate or selective embodiment that is mutually exclusive with other embodiments.

[0029] Secondly, the present invention is described in detail with reference to the schematic diagram. When describing the embodiments of the present invention in detail, for the sake of convenience, the cross-sectional diagrams showing the device structure will not be partially enlarged according to the general scale, and the schematic diagrams are only examples, which should not limit the scope of protection of the present invention. In addition, in actual production, the three-dimensional dimensions of length, width and depth should be included.

[0030] Reference Figure 1 -3, provides a method for evaluating the degree of temperature segregation of asphalt mixture during pavement paving, comprising the following steps:

[0031] Step 1: Use an infrared thermal imager to scan the asphalt mixture spread on the lane to obtain the temperature value of each point in the target area;

[0032] Step 2: Eliminate unrepresentative temperature data in the target area;

[0033] Step 3: Combine the normal construction temperature range of asphalt mixture and the temperature range standard of asphalt mixture temperature segregation, and classify the remaining data according to the temperature range;

[0034] Step 4: For each type of classified data, add up their respective quantities with a certain weight to obtain the temperature segregation degree of the target area, and make an overall quantitative evaluation of the temperature segregation degree in the target area.

[0035] Among them, in the step one, the field of view angle range of the infrared thermal imager is adjusted according to the size of the target area, and the infrared image is obtained after focusing. Specifically, in the step one, the infrared thermal image taken on site is imported into the infrared image analysis software for processing, and the temperature measurement distance, relative humidity, emissivity and reflection temperature are set according to the actual situation of the construction site, and blue and red are selected to represent the lower and higher areas of the road surface temperature respectively; the target area is selected, and the length L and width W of the road surface behind the paver on the construction site where temperature data needs to be collected are determined, and a point is taken at a distance a along the longitudinal and transverse directions of the lane, and n points are taken on the target area to obtain the temperature value t of each point in the target area. x,y , where x and y represent the x-coordinate and y-coordinate of the location of the unit, respectively. n temperature data are obtained, and the longitudinal direction of the lane is the x-axis, with a total of n x points; along the lane horizontally is the y-axis, there are n points in total y points; n = n x ×n y , unit: m.

[0036] The method of eliminating in step 2 includes: for any unit temperature value t x,y , take the average temperature value Eva of all units within a certain area around it x,y , the x-coordinate range of the area is [xa,x+a], the y-coordinate range is [y-1.25,y+1.25], x∈[2a,n x -a],y∈[1.25+a,n y -1.25], unit: m;

[0037] Among them, if Eva x,y <160℃, then remove t x,y , otherwise keep t x,y , and finally the remaining n r Temperature data.

[0038] Furthermore, in the step three, the density and void ratio changes of the asphalt mixture under different temperature change ranges are analyzed: when the temperature changes from 0 to 10°C, the temperature interval is defined as the no temperature segregation interval T0; when the temperature changes from 10 to x1°C, the temperature interval is defined as the mild temperature segregation interval T1; when the temperature changes from x1 to x2°C, the temperature interval is defined as the moderate temperature segregation interval T2; when the temperature changes from x2 to x3°C, the temperature interval is defined as the severe temperature segregation interval T3; the four temperature intervals T0, T1, T2 and T3 correspond to the sets c0, c1, c2 and c3, respectively.

[0039] Specifically, the classification method in step 3 is as follows: select a data a1 from set C, and the rest of the data is a i, i = 1, 2, 3…n, compare data a1 with other data a in set C i Take the absolute value of the difference d i , i=1,2,3…n; select d in the temperature intervals T0, T1, T2 and T3 i The interval in which it is located is stored in the set c0, c1, c2 or c3 corresponding to the interval. Finally, the number of elements in the four sets c0, c1, c2 and c3 are count_c0, count_c1, count_c2 and count_c3 respectively.

[0040] Among them, in the step 4, count_c0, count_c1, count_c2 and count_c3 are weighted averaged, and the weights are 0, and The index representing the degree of temperature segregation in the construction section is obtained:

[0041]

[0042] The present invention collects the temperature in the plane of the paver working section in real time online, can truly and comprehensively reflect the temperature distribution of the asphalt mixture in the construction section, proposes an index to characterize the temperature segregation degree of the asphalt mixture in the construction section, and can quantitatively compare the temperature segregation degree of the asphalt mixture in different construction sections; the method is used to evaluate the segregation degree of the asphalt mixture during asphalt pavement paving, and has simple operation, low cost and strong characterization; the method can effectively improve the management level and construction quality of road engineering construction, and has good market prospects and economic benefits.

[0043] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should all be included in the scope of the claims of the present invention.

Claims

1. A method for evaluating the degree of temperature segregation of asphalt mixture during pavement paving, characterized in that: The following steps are involved: Step 1: Use an infrared thermal imager to scan the asphalt mixture spread on the lane to obtain the temperature value of each point in the target area; Step 2: Eliminate unrepresentative temperature data in the target area; Step 3: Combine the normal construction temperature range of asphalt mixture and the temperature range standard of asphalt mixture temperature segregation, and classify the remaining data according to the temperature range; Step 4: For each type of classified data, add up their respective quantities with a certain weight to obtain the temperature segregation degree of the target area, and make an overall quantitative evaluation of the temperature segregation degree in the target area.

2. The method for evaluating the degree of temperature segregation of asphalt mixture during road paving according to claim 1, characterized in that: In the step 1, the field of view angle range of the infrared thermal imager is adjusted according to the size of the target area, and the camera is photographed after focusing to obtain an infrared image.

3. The method for evaluating the degree of temperature segregation of asphalt mixture during road paving according to claim 2, characterized in that: In the step 1, the infrared thermal image taken on site is imported into the infrared image analysis software for processing, the temperature measurement distance, relative humidity, emissivity and reflection temperature are set according to the actual situation of the construction site, and blue and red are selected to represent the lower and higher areas of the road surface temperature respectively; Select the target area, determine the length L and width W of the road surface behind the paver at the construction site where the temperature data needs to be collected, select a point at a distance a along the longitudinal and transverse directions of the lane, select n points on the target area, and obtain the temperature value t of each point in the target area. x,y , where x and y represent the x-coordinate and y-coordinate of the location of the unit, respectively. n temperature data are obtained, and the longitudinal direction of the lane is the x-axis, with a total of n x points; along the lane horizontally is the y-axis, there are n points in total y points; n = n x ×n y , unit: m.

4. The method for evaluating the degree of temperature segregation of asphalt mixture during road paving according to claim 3, characterized in that: The method of eliminating in step 2 includes: for the temperature value t of any unit x,y , take the average temperature value Eva of all units within a certain area around it x,y , the x-coordinate range of the area is [xa,x+a], the y-coordinate range is [y-1.25,y+1.25], x∈[2a,n x -a],y∈[1.25+a,n y -1.25], unit: m; Among them, if Eva x,y <160℃, then remove t x,y , otherwise keep t x,y , and finally the remaining n r Temperature data.

5. The method for evaluating the degree of temperature segregation of asphalt mixture during road paving according to claim 4, characterized in that: In the step three, the density and void ratio changes of the asphalt mixture under different temperature ranges are analyzed: when the temperature changes from 0 to 10°C, the temperature interval is defined as the no temperature segregation interval T0; when the temperature changes from 10 to x1°C, the temperature interval is defined as the mild temperature segregation interval T1; when the temperature changes from x1 to x2°C, the temperature interval is defined as the moderate temperature segregation interval T2; when the temperature changes from x2 to x3°C, the temperature interval is defined as the severe temperature segregation interval T3; the four temperature intervals T0, T1, T2 and T3 correspond to the sets c0, c1, c2 and c3 respectively.

6. The method for evaluating the degree of temperature segregation of asphalt mixture during road paving according to claim 5, characterized in that: The classification method in step 3 is as follows: select a data a1 from set C, and the rest of the data is a i , i = 1, 2, 3…n, compare data a1 with other data a in set C i Take the absolute value of the difference d i , i=1,2,3…n; select d in the temperature intervals T0, T1, T2 and T3 i The interval in which it is located is stored in the set c0, c1, c2 or c3 corresponding to the interval. Finally, the number of elements in the four sets c0, c1, c2 and c3 are count_c0, count_c1, count_c2 and count_c3 respectively.

7. The method for evaluating the degree of temperature segregation of asphalt mixture during road paving according to claim 6, characterized in that: In the step 4, count_c0, count_c1, count_c2 and count_c3 are weighted averaged, and the weights are 0, and The index representing the degree of temperature segregation in the construction section is obtained:

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