Method for testing gap distribution uniformity and drainage performance of porous asphalt pavement

Abstract

The invention discloses a porous asphalt pavement gap distribution uniformity and drainage performance testing method. A porous asphalt pavement needing to be tested is divided into a plurality of test road sections; detecting the water seepage conditions of n measuring points in the transverse direction h and the longitudinal direction z of the test road section by adopting a pavement water seepage instrument; driving the rainfall simulation device into a test road section; before testing, the rainfall simulation device is calibrated, the uniform spraying effect of the rainfall simulation device is ensured, the minimum rainfall intensity can be simulated and measured, and meanwhile all interfaces are checked to ensure tight connection; performing water seepage condition retest on the test road section by using a rainfall simulation device, and selecting m test points; and uniformly analyzing gap distribution of the test road section. According to the method, firstly, a road surface runoff scene can be truly simulated, the problem of lateral seepage interference is solved, the overall water seepage condition of a road section can be accurately evaluated, and the pavement water seepage qualification misjudgment rate is reduced; meanwhile, the construction segregation degree is revealed through the data difference between the water seepage instrument (point) and the rainfall simulation (surface). The method is high in operability, convenient to understand and real and reliable in data, and is a simple, convenient and visual test method.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of road engineering, and particularly relates to a method for testing the uniformity of void distribution and drainage performance of porous asphalt pavement. BACKGROUND

[0002] In recent years, porous asphalt pavement has been widely used in the southern rainy areas for its excellent drainage function. Under the condition of rainfall, the drainage asphalt pavement can quickly drain the rainwater on the road surface in a short time, reduce the risk of water accumulation on the road surface, and improve the driving safety (according to the investigation, the traffic accident rate can be reduced by about 50% after paving the drainage asphalt pavement). Therefore, in order to ensure that the porous asphalt pavement has good drainage performance after construction, it is particularly necessary to judge the uniformity of void distribution and test and evaluate the drainage performance.

[0003] At present, there is no effective method for testing the uniformity of void distribution of porous asphalt pavement, which is generally indirectly judged by evaluating the water seepage condition; and the drainage performance is mainly tested by using a pavement water seepage instrument to measure the water seepage amount per unit time to evaluate the water seepage condition of the pavement. However, this method has three defects: first, the water seepage coefficient of the porous asphalt pavement is very large, and 500 mL of water can be seeped into the pavement in 3-4 s (the vertical seepage speed is fast), so it is difficult to obtain accurate and effective test results by using this method to measure the water seepage coefficient of the porous asphalt pavement; second, the water seepage of the porous asphalt pavement includes vertical seepage and horizontal seepage, and when the water seepage coefficient of the pavement is tested by using this method, there is a prominent lateral seepage problem, so the measured water seepage coefficient is difficult to effectively evaluate the real water seepage performance of the porous asphalt pavement; third, the drainage asphalt mixture has many coarse aggregates and large voids, and the mixture is easy to produce fluctuation and segregation during transportation, paving and compaction, which leads to uneven construction quality of the drainage asphalt pavement, so the average value of the water seepage coefficients of three or five test points measured by using this method is difficult to represent and reflect the water seepage condition of the actual test section.

[0004] The water seepage condition of the porous asphalt pavement is a direct reflection of the uniformity of void distribution. The more uniform the void distribution is, the better the overall water seepage condition of the pavement is; on the contrary, the more uneven the void distribution is, the lower the overall water seepage condition of the pavement will be, and even water accumulation will be formed on the road surface, which reduces the anti-skid performance of the vehicle, so it is extremely important to accurately evaluate the uniformity of void distribution and the water seepage condition of the porous asphalt pavement. However, due to the defects of the existing test method, the uniformity of void distribution and the real water seepage condition of the porous asphalt pavement in the actual engineering cannot be effectively tested, which causes the porous asphalt pavement with unqualified water seepage condition to be evaluated as qualified, and causes the road water accumulation and driving safety in rainy days, and further affects the popularization and application of the porous asphalt pavement.

[0005] In view of this problem, researchers in the industry have tried various improvements, but mainly for the determination of the water seepage condition of porous asphalt pavement, such as the development of electronic water seepage meters, various permeation test devices, etc. to evaluate the water seepage condition of porous asphalt pavement, but these methods are still point detection, and the test results are affected by factors such as construction uniformity, and the water seepage coefficient of some test points is large, and the water seepage coefficient of some test points is small, making it difficult to truly reflect the actual water seepage condition of porous asphalt pavement. Therefore, there is an urgent need for a detection method that can better evaluate the void distribution uniformity and water seepage condition of porous asphalt pavement. SUMMARY

[0006] In view of the above problems, the present application aims to provide a porous asphalt pavement void distribution uniformity and drainage performance test method.

[0007] To achieve this technical purpose, the scheme of the present application is: a porous asphalt pavement void distribution uniformity and drainage performance test method, the specific steps are as follows:

[0008] S1, divide the porous asphalt pavement to be tested into several test sections, and place a nuclear-free density meter at the specified position of the test section for preliminary detection;

[0009] S2, use a road water seepage meter to detect the water seepage condition of n test points in the horizontal direction h and the vertical direction z of the test section, and the water seepage condition in the horizontal direction is denoted as C h1 , C h2 , C h3 ...C hn , and the water seepage condition in the vertical direction is denoted as C z1 , C z2 , C z3 ...C zn , and the average value of the horizontal and vertical water seepage conditions is denoted as

[0010] S3, after the water seepage condition is completed, drive the rainfall simulation device into the test section; before testing, calibrate the rainfall simulation device to ensure uniform spraying effect and simulate the minimum rainfall intensity, and check the interfaces to ensure tight connection;

[0011] S4, use the rainfall simulation device to retest the water seepage condition of the test section, select m test points, and the water seepage condition is denoted as Q1, Q2, Q3...Q m , and the average value is denoted as

[0012] S5, void distribution uniformity analysis of the test section, after the water seepage condition of the test section is detected by the road water seepage meter and the rainfall simulation device, if , then the value measured by the rainfall simulation device system is As an evaluation of the water seepage condition of the asphalt pavement; if It indicates that the overall porous asphalt pavement construction is relatively uniform, the void distribution is relatively uniform, and the water seepage condition is good.

[0013] As preferred, the length of each section of the test section in step S1 is 50m, 11 cross sections are continuously tested at an interval of 5m along the driving direction of each section, each cross section is tested from the inside of the central divider, and 16 test points are continuously tested at an interval of 1.5m;

[0014] In step S1, the relative density p of the test points of the test section is obtained by using the nuclear density gauge; the relative density p measured by the nuclear density gauge is calibrated and corrected to obtain the bulk volume relative density p1 of the test points of the test section, and then the bulk volume relative density p1 is converted and processed with the indoor maximum theoretical relative density p2, so as to obtain the void ratio VV of the test points of the test section.

[0015] As preferred, based on the relationship between the void ratio VV and the water seepage condition of the pavement, when the proportion of the test section with a void ratio VV≥18% is less than 90%, and the water seepage condition C of the test point detected by the water seepage instrument is less than 5000mL / min, the test point is judged as an abnormal data point.

[0016] As preferred, the rainfall simulation device comprises a rainfall water pipe and a water conveying pipe, a watering cart, and a rainwater flow meter; the three or more rainfall water pipes with the same diameter are connected to the water conveying pipe at one end, and the other end of the rainfall water pipe is sealed; one end of the water conveying pipe is sealed, and the other end is connected to the watering cart; a rainwater flow meter for controlling the rainfall intensity is arranged between the water conveying pipe and the watering cart;

[0017] The diameter of the rainfall water pipe is Φ32mm, the rainfall hole is a micropore with a diameter of 1-2mm, and the micropore spacing is 2cm, so that the uniformity of the water curtain reaches more than 95%, effectively inhibiting lateral seepage; the diameter of the water conveying pipe is Φ64mm, and the length is 3.75m; the water conveying pipe is provided with five or more interfaces on the left and right sides; the rainfall water pipe is connected to the water conveying pipe through a nut; the watering cart is provided with a water pump for water pumping and pressurization; the watering cart is conveyed to the rainfall water pipes uniformly distributed in the transverse direction of the lane through the water conveying pipe.

[0018] As preferred, the number of rainfall pipes of the rainfall simulation device is set according to the number of lanes in step S3; 2-5 rainfall pipes are uniformly arranged for each lane; five 50cm×50cm capacity bottles are placed in the length direction of a lane, and three 50cm×50cm capacity bottles are placed in the width direction of a lane.

[0019] During the calibration test, the rainfall intensity was set to 1 mm / min, corresponding to a flow rate of 22.5 L per minute for the corresponding lane. If the spraying effect of the rainfall device in that lane is relatively uniform, the amount of water falling into the volumetric flask after 1 minute of simulated rainfall should be closer to the theoretical value of 2500 mL. According to the field test, when four rainfall pipes are symmetrically arranged on both sides of the water supply pipeline, the amount of water in the volumetric flask is close to 2500 mL. The rainfall pipe has the best spray uniformity and can ensure that uniform rainfall effect is achieved under the minimum rainfall intensity selected in the test.

[0020] As a preferred option, rubber gaskets are installed between the rainwater pipe and the water delivery pipe, and between the water truck and the water delivery pipe to prevent water leakage for transitional connection.

[0021] As a preferred method, the flow meter reading is taken when runoff occurs on the road surface. The measurement is repeated three times at the same location to ensure the accuracy of the test results. The average value of the readings is taken, which is the maximum rainfall Q that the porous asphalt pavement can withstand.

[0022] The beneficial effects of this invention are as follows: Firstly, the method of this application can realistically simulate road surface runoff scenarios, solving the problem of lateral infiltration interference, and accurately evaluate the overall infiltration status of a road section, reducing the misjudgment rate of road surface infiltration compliance. Secondly, by comparing the data from the infiltration meter (point) and the rainfall simulation (surface), the degree of construction segregation can be revealed. The method of this application is highly operable, easy to understand, and provides reliable data, making it a simple, easy-to-implement, and intuitive experimental method. Attached Figure Description

[0023] Fig. 1 This is a distribution diagram of the porosity measurement points in the test section of the present invention;

[0024] Fig. 2 This is a void ratio distribution cloud map of the test section of the present invention.

[0025] Fig. 3 This is a diagram showing the number and location of the rainfall pipes in the rainfall simulation device of the present invention. Detailed Implementation

[0026] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0027] like Figs. 1-3 As shown, the specific embodiment of the present invention is a method for testing the uniformity of void distribution and drainage performance of porous asphalt pavement, and the specific steps are as follows:

[0028] S1. Divide the porous asphalt pavement to be tested into several test sections, and place a density meter without nuclei at a designated location in the test section for preliminary testing.

[0029] S2. A pavement permeability meter is used to detect the permeability at n measuring points along the transverse (h) and longitudinal (z) axes of the test section. The permeability measured in the transverse direction is recorded as C. h1 C h2 C h3 ...C hn The longitudinal measurement of seepage is denoted as C. z1 C z2 C z3 ...C zn The average values ​​of transverse and longitudinal seepage conditions are denoted as

[0030] S3. After the water seepage condition is completed, drive the rainfall simulation device into the test section; before the test, calibrate the rainfall simulation device to ensure that it sprays evenly and can simulate and measure the minimum rainfall intensity, and check each interface to ensure that the connection is tight.

[0031] S4. Use a rainfall simulation device to re-measure the seepage condition of the test section, selecting m measuring points, and recording the seepage condition as Q1, Q2, Q3...Q m The average value is denoted as

[0032] S5. Analysis of uniform void distribution in the test section: After testing the permeability of the test section using a pavement permeability meter and a rainfall simulation device, if... The rainfall simulation device system was used to measure the rainfall. As an evaluation of the water seepage condition of asphalt pavement; if This indicates that the construction of porous asphalt pavement is generally uniform, the voids are evenly distributed, and the water permeability is good.

[0033] In step S1, each test section is 50m long. Each section has 11 cross sections tested continuously at 5m intervals along the direction of travel. Each cross section starts from the inside of the central divider and has 16 test points tested continuously at 1.5m intervals.

[0034] In step S1, the relative density ρ of the test road section measuring points is obtained using a nucleus-free density meter. The relative density ρ measured by the nucleus-free density meter is calibrated and corrected to obtain the bulk relative density ρ1 of the test road section measuring points. This ρ1 is then converted to the maximum theoretical relative density ρ2 obtained indoors to obtain the porosity VV of the test road section measuring points. Based on the relationship between porosity (VV) and pavement permeability, if the proportion of test sections with porosity (VV) ≥ 18% is less than 90%, and the pavement permeability (C) detected by the pavement permeability meter at the measuring point is < 5000 mL / min, the measuring point is judged as an abnormal data point.

[0035] The rainfall simulation device comprises a rainfall water pipe and a water conveying pipe, a watering cart, and a rainwater flow meter; three or more rainfall water pipes with the same diameter are connected to the water conveying pipe at one end, and the other end of the rainfall water pipe is sealed; one end of the water conveying pipe is sealed, and the other end is connected to the watering cart; a rainwater flow meter for controlling the rainfall intensity is arranged between the water conveying pipe and the watering cart;

[0036] The diameter of the rainfall water pipe is Φ32 mm, the rainfall hole is a micropore with a diameter of 1-2 mm, and the micropore spacing is 2 cm, so that the uniformity of the water curtain is more than 95%, and the lateral penetration is effectively inhibited; the diameter of the water conveying pipe is Φ64 mm, and the length is 3.75 m; the water conveying pipe is provided with five or more interfaces on the left and right sides; the rainfall water pipe is connected to the water conveying pipe through a nut; the watering cart is provided with a water pump for water pumping and pressurization; the watering cart is conveyed to the rainfall water pipes uniformly distributed in the transverse direction of the lane through the water conveying pipe. In step S3, the number of rainfall pipes of the rainfall simulation device is set according to the number of lanes; 2-5 rainfall pipes are uniformly arranged for each lane; five 50cm×50cm capacity bottles are respectively arranged in the length direction of a lane, and three 50cm×50cm capacity bottles are respectively arranged in the width direction of the lane;

[0037] During calibration test, the rainfall intensity is set to 1mm / min, and the flow of the 1min water meter corresponding to the lane is 22.5L; if the spraying effect of the rainfall device of the lane is more uniform, the water falling into the capacity bottle after 1min of simulated rainfall should be closer to the theoretical value of 2500mL; through field test, when four rainfall pipes are symmetrically arranged on the left and right sides of the water conveying pipe, the water amount in the capacity bottle is close to 2500mL, the spraying uniformity of the rainfall pipe is the best, and the uniform rainfall effect can be realized at the minimum rainfall intensity selected in the test.

[0038] Rubber gaskets for preventing water seepage are arranged between the rainfall water pipe and the water conveying pipe and between the watering cart and the water conveying pipe for transition connection. When the runoff phenomenon occurs on the road surface of the rainwater flow meter, the flow meter reading is read; at the same time, the test result accuracy is ensured by repeatedly measuring three times at the position, and the average value of the readings is the maximum rainfall amount Q that can be borne by the porous asphalt pavement.

[0039] Example 1

[0040] In order to evaluate the void distribution uniformity and water seepage condition of a one-way five-lane porous asphalt pavement test section P1 (K13+530-K13+580), the non-nuclear density gauge and the rainfall simulation device are used to perform the test according to the above steps, and the test result is compared with the test result of the pavement water seepage instrument.

[0041] Table 1-1 Test result of water seepage condition of test section P1

[0042]

[0043] Table 1-2 Test section P1 lane level water infiltration condition test results

[0044]

[0045] Note: Table 1-1, the "bold" data indicates that the water infiltration condition is larger here, and the construction compaction is uneven; the "underlined" test data is abnormal data.

[0046] (K13+530~K13+580) section test results are shown in Table 1-1 and Table 1-2 Fig. 2 and Table 1-1 test section P1 water infiltration condition test results (void ratio 20%, drainage layer thickness 4 cm), Table 1-2 test section P1 lane level water infiltration condition test results.

[0047] From the above Table 1-1 and 1-2, it can be seen that the original detection method has certain applicability, but since the coarse aggregate of porous asphalt pavement accounts for a large proportion, it is easy to produce segregation in the process of mixing, transportation and paving, causing uneven distribution of voids of porous asphalt pavement after construction and other problems, resulting in certain differences in water infiltration conditions of each test point. The method of the present application can generally more accurately evaluate the uniformity of void distribution and the overall water infiltration effect of the section of porous asphalt pavement. Further analysis shows that the average void ratio of test section P1 of porous asphalt pavement is in the range of 19.26%~21.32%, with an average of 20.87%, and the average void ratio meets the design requirements (18%~22%), and only individual positions have larger void ratio, and the void ratio is well controlled.

[0048] For test section P1 of porous asphalt pavement, the longitudinal and transverse water infiltration conditions measured by the pavement water infiltration instrument fluctuate greatly, such as the second test point of lane G, the longitudinal water infiltration condition is 5306 mL / min, the transverse water infiltration condition is 3781 mL / min, 5402 mL / min and 5221 mL / min, and there is a large deviation in the transverse water infiltration condition of individual points, indicating that the water infiltration condition measured by the pavement water infiltration instrument is difficult to stably evaluate the water infiltration effect of the pavement; and when the rainfall simulation device is used to measure the water infiltration performance of the pavement, the water infiltration capacity of the measurement section is generally stable. By comparing the water infiltration conditions measured by the rainfall simulation device and the pavement water infiltration instrument, the water infiltration conditions of lane C and lane X indicate that the water infiltration condition measured by the rainfall simulation device system is less than that measured by the electronic water infiltration instrument, and at this time the void ratio distribution of the porous asphalt pavement is uneven, causing a large difference in water infiltration condition; and for the water infiltration conditions of lane A, lane E and lane G indicate that at this time the difference between the water infiltration conditions measured by the two methods is small, the overall construction of the porous asphalt pavement is uniform, the void distribution is uniform, and the water infiltration condition is good.

[0049] Meanwhile, the comparison of the water penetration conditions of Table 1-1 and Table 1-2 also finds that the misjudgment rate of the traditional detection method is basically greater than that of the rainfall simulation device, which indicates that the determination of the water penetration condition of the road surface by only relying on the road surface water penetration instrument is easy to lead to misjudgment and is difficult to evaluate the real water penetration condition of the porous asphalt road surface.

[0050] The above is only the preferred embodiment of the present application, and is not used to limit the present application. Any slight modification, equivalent replacement and improvement made to the above embodiment according to the technical essence of the present application shall be included in the protection scope of the technical scheme of the present application.

Claims

1. A method for testing the uniformity of void distribution and drainage performance of porous asphalt pavement, characterized in that, The specific steps are as follows: S1. Divide the porous asphalt pavement to be tested into several test sections, and place a density meter without nuclei at a designated location in the test section for preliminary testing. S2. A pavement permeability meter is used to detect the permeability at n measuring points along the transverse (h) and longitudinal (z) axes of the test section. The permeability measured in the transverse direction is recorded as C. h1 C h2 C h3 ...C hn The longitudinal measurement of seepage is denoted as C. z1 C z2 C z3 ...C zn The average values ​​of transverse and longitudinal seepage conditions are denoted as S3. After the water seepage condition is completed, drive the rainfall simulation device into the test section; before the test, calibrate the rainfall simulation device to ensure that it sprays evenly and can simulate and measure the minimum rainfall intensity, and check each interface to ensure that the connection is tight. S4. Use a rainfall simulation device to re-measure the seepage condition of the test section, selecting m measuring points, and recording the seepage condition as Q1, Q2, Q3...Q m The average value is denoted as ; S5. Analysis of uniform void distribution in the test section: After testing the permeability of the test section using a pavement permeability meter and a rainfall simulation device, if... >450 mL / min, then measured by the rainfall simulation device system. As an evaluation of the water seepage condition of asphalt pavement; if A flow rate of ≤450mL / min indicates that the construction of porous asphalt pavement is generally uniform, the void distribution is relatively uniform, and the water permeability is good.

2. The method for testing the uniformity of void distribution and drainage performance of porous asphalt pavement according to claim 1, characterized in that: In step S1, each test section is 50m long. Each section has 11 cross sections tested continuously at 5m intervals along the direction of travel. Each cross section starts from the inside of the central divider and has 16 test points tested continuously at 1.5m intervals. In step S1, the relative density ρ of the test road section measuring points is obtained using a nucleus-free density meter. The relative density ρ measured by the nucleus-free density meter is calibrated and corrected to obtain the bulk relative density ρ1 of the test road section measuring points. This ρ1 is then converted to the maximum theoretical relative density ρ2 obtained indoors to obtain the porosity VV of the test road section measuring points. .

3. The method for testing the uniformity of void distribution and drainage performance of porous asphalt pavement according to claim 2, characterized in that: Based on the relationship between porosity VV and pavement permeability, if the proportion of test sections with porosity VV ≥ 18% is less than 90%, and the pavement permeability C detected by the pavement permeability meter is less than 5000 mL / min, the test point is judged to be an abnormal data point.

4. The method for testing the uniformity of void distribution and drainage performance of porous asphalt pavement according to claim 3, characterized in that: The rainfall simulation device includes rainwater pipes and water delivery pipes, a water truck, and a rainwater flow meter; three or more rainwater pipes of equal diameter are connected at one end to the water delivery pipe, and the other end of the rainwater pipes is sealed; one end of the water delivery pipe is sealed, and the other end is connected to the water truck; a rainwater flow meter is installed between the water delivery pipe and the water truck to control the rainfall intensity. The rainwater pipe has a diameter of Φ32mm, and the rainwater channels are micropores of 1-2mm with a micropore spacing of 2cm, ensuring that the water curtain coverage is more than 95% uniform and effectively suppressing lateral seepage; the water delivery pipe has a diameter of Φ64mm and a length of 3.75m, with more than 5 interfaces on each side of the water delivery pipe, and the rainwater pipe and the water delivery pipe are connected by nuts; the sprinkler truck is equipped with a water pump for water extraction and pressurization, and the sprinkler truck delivers water to the rainwater pipes that are evenly distributed across the lane through the water delivery pipe.

5. The method for testing the uniformity of void distribution and drainage performance of porous asphalt pavement according to claim 3, characterized in that: In step S3, the number of rain pipes of the rain simulation device is set according to the number of lanes; 2-5 rain pipes need to be evenly laid out in each lane; 5 volumetric flasks of 50cm×50cm are placed in the length direction of a lane and 3 volumetric flasks of 50cm×50cm are placed in the width direction. During the calibration test, the rainfall intensity was set to 1 mm / min, corresponding to a flow rate of 22.5 L per minute for the corresponding lane. If the spraying effect of the rainfall device in that lane is relatively uniform, the amount of water falling into the volumetric flask after 1 minute of simulated rainfall should be closer to the theoretical value of 2500 mL. According to the field test, when four rainfall pipes are symmetrically arranged on both sides of the water supply pipeline, the amount of water in the volumetric flask is close to 2500 mL. The rainfall pipe has the best spray uniformity and can ensure that uniform rainfall effect is achieved under the minimum rainfall intensity selected in the test.

6. The method for testing the uniformity of void distribution and drainage performance of porous asphalt pavement according to claim 3, characterized in that: Rubber gaskets are installed between the rainwater pipe and the water delivery pipe, and between the water truck and the water delivery pipe to prevent water leakage and facilitate transition connections.

7. The method for testing the uniformity of void distribution and drainage performance of porous asphalt pavement according to claim 3, characterized in that: When runoff occurs on the rainwater flow meter, read the flow meter reading; repeat the measurement three times at the same location to ensure the accuracy of the test results, and take the average value of the readings, which is the maximum rainfall Q that the porous asphalt pavement can withstand.

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