Method for evaluating loose asphalt pavement

Abstract

The present application provides a loose evaluation method for asphalt pavement, and belongs to the technical field of loose evaluation for asphalt pavement. The aggregate cleaning device is used to sweep and collect loose aggregate of the asphalt pavement in a specific area. The collected aggregate is conveyed to a vibration table for vibration and shaking. A laser array is used for scanning to obtain the particle size of all aggregates. The particle sizes of all aggregates are compared to obtain the particle size of the largest aggregate. Then, the identification range size is selected according to the particle size of the largest aggregate. The laser imaging principle is used to irradiate and identify the asphalt pavement from the top of the pavement to obtain each spalling pit hole in the test area. The loose rate of the asphalt pavement is calculated according to the size of the aggregate and the spalling pit hole. Then, the loose degree of the asphalt pavement is evaluated according to the loose rate. The scattered aggregate is collected for detection and grouping. The particle size of the aggregate is used as the reference value of the measurement range to realize more accurate measurement of the spalling pit hole area. The whole measurement process does not involve cutting the pavement or digging, which well protects the road.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of loose evaluation of asphalt pavement, in particular to a loose evaluation method of asphalt pavement. BACKGROUND

[0002] The existing loose evaluation method of asphalt pavement is mainly the Kentaur flying test introduced in the highway engineering asphalt and asphalt mixture test regulation. The test is to rotate and impact the Marshall test piece in the Los Angeles test machine for a specified number of times, and the mass percentage of the scattered material of the asphalt mixture test piece is taken as the evaluation index. The main function of the above standard flying test is to evaluate the water stability of the asphalt mixture and determine the minimum asphalt content required for the surface layer of the asphalt pavement. At the same time, this method can also be used to evaluate the degree of loose of the surface aggregate of the pavement under the action of traffic load due to insufficient asphalt content or adhesion. The problems of the above test method are as follows: 1. The Kentaur flying test is an indoor asphalt mixture test, which cannot be used for field evaluation; 2. The evaluation of the existing road needs to cut the sample, which has a great destructive effect on the road. Therefore, an automatic loose evaluation method of asphalt pavement is needed. SUMMARY

[0003] The purpose of the present application is to provide a loose evaluation method of asphalt pavement to solve the technical problems mentioned in the background.

[0004] In order to achieve the above purpose, the technical scheme adopted by the present application is as follows:

[0005] The loose evaluation method of asphalt pavement comprises the following steps:

[0006] Step 1: using the aggregate cleaning device to clean and collect the loose aggregate of the asphalt pavement in a specific area;

[0007] Step 2: conveying the collected aggregate to the vibration table for vibration and shaking;

[0008] Step 3: using the laser array to scan to obtain the particle size of all aggregates;

[0009] Step 4: comparing the particle sizes of all aggregates to obtain the particle size of the largest aggregate, and then selecting the identification range size according to the particle size of the largest aggregate;

[0010] Step 5: using the laser imaging principle to irradiate and identify the asphalt pavement from the top of the pavement to obtain each spalling pit in the test area;

[0011] Step 6: calculating the loose rate of the asphalt pavement according to the size of the aggregate and the spalling pit;

[0012] Step 7: then evaluating the loose degree of the asphalt pavement according to the loose rate of the asphalt pavement.

[0013] Further, the specific process of step 1 is: on the asphalt pavement, an area is arbitrarily demarcated, and a white square frame is demarcated on the outside of the area, the aggregate and ash layer on the pavement are swept using a sweeping and dust collecting device to obtain a clean asphalt pavement, the swept aggregate, ash layer and garbage are put into a vibrating screen to vibrate and start a blower to blow away the garbage and dust, and then the clean aggregate is obtained.

[0014] Further, the specific steps of step 2 are: the collected aggregate is put into a sieve for filtering, aggregate smaller than a set diameter is filtered out, aggregate larger than the set diameter is obtained, and then the remaining aggregate is put into a vibrating table in batches for vibration to make the aggregate spread out, and an image recognition camera at the top end shoots a video in real time to determine whether the aggregate has completely spread out, wherein the vibrating table starts vibrating for a fixed time, then stops for a fixed time, the image recognition camera recognizes the outer contour of the aggregate to determine whether it has completely spread out, the judgment condition for complete spreading out is that the recognized aggregate contour is a closed structure, and the length of the recognized aggregate closed contour cannot be greater than a set length value, the set length value is the maximum value of the standard aggregate particle size of road construction, when the image recognition camera recognizes that the aggregate in a certain area has not spread out, the point of the vibrating table is controlled to be the area where the aggregate has not spread out, then the vibration stops after a set time, the image recognition camera recognizes the outer contour of the aggregate again, and the steps of vibration and recognition are repeated until the aggregate completely spreads out.

[0015] Further, the specific process of step 3 is: a laser array is used to move and scan on the X and Y axes to obtain a three-dimensional model of each aggregate, then the specific size of the three-dimensional model is calculated to calculate the particle size of each aggregate, and the number of aggregates is counted, and the particle size of the aggregate is classified and stored after each recognition.

[0016] Further, the specific process of step 4 is: after measuring the particle size of all aggregates, the aggregate particle size is grouped according to stages to obtain an aggregate particle size array, the grouping condition is that the first group is aggregate particle size greater than or equal to the maximum value of the standard aggregate particle size of road construction * 0.9, the second group is aggregate particle size greater than or equal to the maximum value of the standard aggregate particle size of road construction * 0.8 but less than the particle size of the first group, then the third group is aggregate particle size greater than or equal to the maximum value of the standard aggregate particle size of road construction * 0.7 but less than the particle size of the second group, then the fourth group is aggregate particle size greater than or equal to the maximum value of the standard aggregate particle size of road construction * 0.6 but less than the particle size of the third group, then the fifth group is aggregate particle size greater than or equal to the maximum value of the standard aggregate particle size of road construction * 0.5 but less than the particle size of the fourth group, and the remaining aggregate particle size is the last group.

[0017] Select the first group of aggregate particle size, called the nominal aggregate particle size, then the particle size of each aggregate is the reference value, first from the largest aggregate, from large to small, 20 times the reference value as the diameter of the circle as the inspection measurement area, or with the maximum diameter of the spalling aggregate as the reference value, 20 times the diameter of the circle as the inspection measurement area, each aggregate is set a detection area, until the original area is measured or the first group of aggregate quantity is used up, the original area can get several different selected identification range area.

[0018] Further, the specific process of step 5 is: using a white paint to draw all selected identification range areas, and then using a laser array to identify the clean selected identification range area to obtain the diameter of the spalling pit in each selected identification range area. When the spalling pit is irregularly circular, the center point of the selected spalling pit is taken as the center of the circle, and then the side of the spalling pit is drawn into a circle, so that the side point of the spalling pit falls on the edge of the circle. At this time, the diameter of the circle is the diameter of the spalling pit. When the depth of the spalling pit is greater than 5mm, it is considered that the area is a spalling pit. When the depth is greater than 2 times the nominal aggregate particle size, it is not counted as loose.

[0019] Further, the specific process of step 6 is: calculating the spalling pit area in all areas according to the diameter of the spalling pit identified in step 5, calculating the area of the selected identification range area, calculating the number of aggregates in the group with the largest number, and then taking the average value of the particle size of the aggregate in the group to obtain the aggregate particle size correction value. Then the loose rate is equal to (the total area of the spalling pit + the particle size correction value) / the area of all selected identification range areas.

[0020] Further, the specific process of step 7 is: the loose rate is less than 2% and is not counted as loose, 2-10% is evaluated as light loose, 20-30% is moderate loose, and greater than 30% is heavy loose. For aggregates that cannot be cleaned or do not have cleaning conditions, but the original pavement has dropped particle loose, the total pit area is divided by the test area to record the loose rate.

[0021] The present application has the following beneficial effects due to the adoption of the above technical scheme:

[0022] The present application collects the scattered aggregate for detection and grouping, and then takes the aggregate particle size as the reference value of the measurement range. The present application can more accurately measure the spalling pit area, and does not involve cutting the pavement or digging during the entire measurement process, which can well protect the road and does not need to be repaired. The traditional detection method is to cut the plane, which damages the structure of the road and needs to be repaired or causes irreversible damage to the road. BRIEF DESCRIPTION OF DRAWINGS

[0023] Figure 1is a flow chart of the method of the present application. DETAILED DESCRIPTION

[0024] In order to make the objects, technical solutions and advantages of the present application clearer, the present application will be further described in detail below with reference to the drawings and preferred embodiments. However, it should be noted that many details in the description are only for the purpose of making the reader have a thorough understanding of one or more aspects of the present application, and the aspects of the present application can be realized even without these specific details.

[0025] As shown in Figure 1 The asphalt pavement loose evaluation method comprises the following steps:

[0026] Step 1: Use the aggregate sweeping device to sweep and collect the loose aggregate of the asphalt pavement in a specific area. On the asphalt pavement, an area is arbitrarily demarcated, and a white square frame is demarcated on the outside of the area. The sweeping and dust collecting device is used to sweep the aggregate and the ash layer on the pavement to obtain a clean asphalt pavement. The aggregate, ash layer and garbage swept up are put into a vibrating screen to vibrate and start the air blower to blow away the garbage and dust, and then the clean aggregate is obtained.

[0027] Firstly, a flat road surface needs to be selected, and then construction avoidance markers are placed. When vehicles avoid, the aggregate collecting device is placed in the specified area, which is considered to be demarcated. Generally, a square or rectangular area is considered to be demarcated. White tape is used as the demarcation limit of the area, so that it is easier to identify. Because the road surface is black, black identification cannot be used, and only white identification can be used, which is better for identification.

[0028] Step 2: The collected aggregate is conveyed to the vibrating table for vibration and shaking. The collected aggregate is put into a sieve for filtering, and aggregate smaller than a set diameter is filtered out to obtain aggregate larger than the set diameter. Then the remaining aggregate is put into the vibrating table in batches for vibration to make the aggregate spread out. An image recognition camera at the top end shoots a video in real time to determine whether the aggregate has completely spread out. Initially, the vibrating table is set to vibrate for a fixed time, and then stops for a fixed time. The image recognition camera identifies the outer contour of the aggregate to determine whether it has completely spread out. The judgment condition for complete spreading out is that the identified aggregate contour is a closed structure, and the length of the identified closed contour of the aggregate cannot be greater than a set length value, which is the maximum value of the standard aggregate particle size of road construction. When the image recognition camera identifies that the aggregate in a certain area has not spread out, the point of the vibrating table is controlled to be the area where the aggregate has not spread out. Then the vibration is stopped after a set time. The image recognition camera identifies the outer contour of the aggregate again, and the steps of vibration and identification are repeated until the aggregate completely spreads out.

[0029] The bottom of the vibration platform is provided with a plurality of vibration small motors. When one motor vibrates, only a certain area is vibrated, and other areas are not vibrated, so that the essence can be better dispersed according to the identification situation in the later period.

[0030] Step 3: Use the laser array to scan to obtain the particle size of all aggregates. Use the laser array to move and scan in the X and Y axes to obtain the three-dimensional model of each aggregate, then measure the specific size of the three-dimensional model, calculate the particle size of each aggregate, and count the number of aggregates. After each identification, the particle size of the aggregate is classified and stored.

[0031] Step 4: Compare the particle sizes of all aggregates to obtain the particle size of the largest aggregate, and then select the identification range size according to the particle size of the largest aggregate. After measuring the particle size of all aggregates, group the aggregate particle sizes according to the stage to obtain an aggregate particle size array. The grouping conditions are as follows: the first group is aggregate particle size greater than or equal to the maximum value of the road construction standard aggregate particle size * 0.9, the second group is aggregate particle size greater than or equal to the maximum value of the road construction standard aggregate particle size * 0.8 but less than the particle size of the first group, then the third group is aggregate particle size greater than or equal to the maximum value of the road construction standard aggregate particle size * 0.7 but less than the particle size of the second group, then the fourth group is aggregate particle size greater than or equal to the maximum value of the road construction standard aggregate particle size * 0.6 but less than the particle size of the third group, then the fifth group is aggregate particle size greater than or equal to the maximum value of the road construction standard aggregate particle size * 0.5 but less than the particle size of the fourth group, and the remaining aggregate particle size is the last group.

[0032] Select the aggregate particle size of the first group as the nominal aggregate particle size, and the particle size of each aggregate as the reference value. Start from the aggregate with the largest particle size, from large to small, and set a detection area with a circle of 20 times the reference value as the diameter. Alternatively, use the maximum diameter of the spalling aggregate as the reference value, and set a detection area with a circle of 20 times the reference value as the diameter. Each aggregate is set with a detection area until the original designated area is measured or the number of aggregates in the first group is used up, and then the original designated area is obtained.

[0033] Step 5: Use the laser imaging principle to irradiate and identify the asphalt pavement from the top of the pavement to obtain the test area of each spalling pit. Use a white paint to draw all the selected identification range areas, and then use a laser array to identify the clean selected identification range area to obtain the diameter of each selected identification range area. When the spalling pit is irregularly circular, select the center point of the spalling pit as the center of the circle, and then draw a circle with the side of the spalling pit, so that the side point of the spalling pit falls on the edge of the circle. At this time, the diameter of the circle is the diameter of the spalling pit. When the depth of the spalling pit is greater than 5mm, it is considered to be a spalling pit area. When the depth is greater than 2 times the nominal aggregate particle size, it is not considered to be loose.

[0034] Step 6: Calculate the loose rate of the asphalt pavement according to the size and spalling pits of the aggregate. Calculate the spalling pit area in all areas according to the diameter of the spalling pit identified in step 5, calculate the area of the selected identification range area, calculate the maximum group of aggregate of all groups, then take out the average value of the particle size of the aggregate in this group, get the aggregate particle size correction value, then the loose rate = (the sum of the spalling pit area + the particle size correction value) / the area of all selected identification range areas.

[0035] Step 7: Then evaluate the loose degree of the asphalt pavement according to the loose rate of the asphalt pavement. Loose rate less than 2% is not counted as loose, 2-10% is evaluated as mild loose, 20-30% is moderate loose, and greater than 30% is severe loose. For those who cannot sweep out the aggregate or do not have the conditions to sweep, but the original pavement has already existed, take the sum of the measured pit area divided by the test area as the loose rate.

[0036] The above is only the preferred embodiment of the present application, it should be noted that for those skilled in the art, without departing from the principles of the present application, can make several improvements and refinements, these improvements and refinements should also be considered as the protection scope of the present application.

Claims

1. Asphalt pavement looseness evaluation method, characterized in that: The method comprises the following steps: Step 1: Use aggregate cleaning equipment to sweep and collect loose aggregates from the asphalt pavement in a specific area; Step 2: Transfer the collected aggregate to a vibration table for shaking; Step 3: Use laser array to scan and obtain the particle size of all aggregates; Step 4: Compare the particle sizes of all aggregates to obtain the particle size of the largest aggregate, and then select the identification range size based on the particle size of the largest aggregate; Step 5: Use laser imaging to illuminate the asphalt pavement from the top of the road surface to identify the spalling potholes in the test area; Step 6: Select the identification range based on the size of the aggregate and the spalling holes; calculate the looseness rate of the asphalt pavement; Step 7: Then evaluate the looseness of the asphalt surface according to the looseness rate of the asphalt pavement; The specific process of step 4 is as follows: after measuring the particle size of all aggregates, the aggregate particle size is grouped according to the stage to obtain an aggregate particle size array. The grouping conditions are: the first group is the aggregate particle size greater than or equal to the maximum value of the road construction standard aggregate particle size * 0.9, the second group is the aggregate particle size greater than or equal to the maximum value of the road construction standard aggregate particle size * 0.8, but smaller than the particle size of the first group, then the third group is the aggregate particle size greater than or equal to the maximum value of the road construction standard aggregate particle size * 0.7, but smaller than the particle size of the second group, then the fourth group is the aggregate particle size greater than or equal to the maximum value of the road construction standard aggregate particle size * 0.6, but smaller than the particle size of the third group, then the fifth group is the aggregate particle size greater than or equal to the maximum value of the road construction standard aggregate particle size * 0.5, but smaller than the particle size of the fourth group, and the remaining aggregate particle size is the last group; The aggregate particle size of the first group is selected as the nominal aggregate particle size. Then, the particle size of each aggregate is used as the reference value. Starting from the aggregate with the largest particle size, from large to small, a circle with a diameter 20 times the reference value is used as the inspection and measurement area. Alternatively, the maximum diameter of the spalled aggregate is used as the reference value, and a circle with a diameter 20 times the reference value is used as the inspection and measurement area. A detection area is set for each aggregate until the originally designated area is measured or the number of aggregates in the first group is used up. Then, a number of selected identification range areas of different sizes within the originally designated area can be obtained. The specific process of step 5 is: use a white brush to draw all the selected identification range areas, and then use a laser array to identify the clean selected identification range areas to obtain the diameter of the spalling pits in each selected identification range area. When the spalling pits are irregular circles, select the center point of the spalling pits as the center of the circle, and then draw a circle on the side of the spalling pits so that the most important point of the side of the spalling pits falls on the edge of the circle. The diameter of the circle at this time is the diameter of the spalling pits. When the depth of the spalling pits is greater than 5mm, it is considered to be the area of ​​the spalling pits. When the depth is greater than 2 times the nominal aggregate particle size, it is not considered loose.

2. The asphalt pavement looseness evaluation method according to claim 1, characterized in that: The specific process of step 1 is: on the asphalt pavement, arbitrarily mark an area, and mark a white box on the outside of the area, use a cleaning and dust collection device to clean the aggregate and ash layer on the pavement to obtain a clean asphalt pavement, and put the cleaned aggregate, ash layer and garbage into the vibrating screen for vibration and turn on the blower to blow away the garbage and dust, and then obtain clean aggregate.

3. The asphalt pavement looseness evaluation method according to claim 1, characterized in that: The specific steps of step 2 are: putting the collected aggregate into the sieve for filtering, filtering out aggregate smaller than the set diameter, obtaining aggregate larger than the set diameter, and then putting the remaining aggregate into the vibration table in batches for vibration to disperse the aggregate. The image recognition camera takes real-time video at the top to determine whether the aggregate has been completely dispersed. Among them, the vibration table sets a fixed vibration time at the beginning, and then stops for a fixed time. The image recognition camera identifies the outer contour of the aggregate to determine whether it is completely dispersed. The judgment condition for complete dispersion is that the identified aggregate contour is a closed structure, and the length of the identified aggregate closed contour cannot be greater than the set length value. The set length value is the maximum value of the standard aggregate particle size for road construction. When the image recognition camera identifies that the aggregate in a certain area is not dispersed, the point of the vibration table is controlled to be the area where the aggregate is not dispersed, and then the vibration stops after the set time. The image recognition camera then identifies the outer contour of the aggregate and repeats the vibration and recognition steps until the aggregate is completely dispersed.

4. The asphalt pavement looseness evaluation method according to claim 1, characterized in that: The specific process of step 3 is: use the laser array to move and scan on the X-axis and Y-axis to obtain a three-dimensional model of each aggregate, then measure the specific size of the three-dimensional model, calculate the particle size of each aggregate, and count the number of aggregates at the same time. After each identification, the particle size of the aggregate is classified and stored.

5. The method for evaluating looseness of an asphalt pavement according to claim 1, wherein: The specific process of step 7 is: a loose rate lower than 2% is not considered loose, 2-10% is assessed as slightly loose, 20-30% is moderately loose, and greater than 30% is severely loose. For those where aggregates cannot be cleaned out or cleaning conditions are not available, but the original road surface already has loose particles, the total area of ​​the measured potholes divided by the test area is recorded as the loose rate.

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