CN115615909A - Indoor aging simulation method based on aging characteristics of medium-sized surface layer materials on asphalt pavement - Google Patents
Indoor aging simulation method based on aging characteristics of medium-sized surface layer materials on asphalt pavement Download PDFInfo
- Publication number
- CN115615909A CN115615909A CN202211156310.3A CN202211156310A CN115615909A CN 115615909 A CN115615909 A CN 115615909A CN 202211156310 A CN202211156310 A CN 202211156310A CN 115615909 A CN115615909 A CN 115615909A
- Authority
- CN
- China
- Prior art keywords
- layer
- aging
- indoor
- asphalt
- layer material
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
Images
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N17/00—Investigating resistance of materials to the weather, to corrosion, or to light
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02A—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE
- Y02A30/00—Adapting or protecting infrastructure or their operation
- Y02A30/60—Planning or developing urban green infrastructure
Abstract
The indoor aging simulation method based on the aging characteristic of the medium surface layer material on the asphalt pavement is provided, and comprises the following steps: 1. determining meteorological data (annual average solar radiation amount, highest temperature average value in 5 years and the like) of an application field of the asphalt pavement to be researched and design thickness of a middle surface layer on the pavement; 2. taking an upper layer and a middle layer of the asphalt pavement to be researched as research objects, and carrying out layered thickness design on the upper layer and the middle layer as a whole; 3. determining indoor aging simulation parameters of each layer of material; 4. preparing each layer of material, placing the material in a set aging environment for aging for a certain time, extracting and recovering, and testing the performance of the sample. Therefore, the method has important significance for expanding the indoor aging simulation method of the asphalt pavement material, improving the verification and application efficiency of the novel pavement material, saving the construction investment of the asphalt pavement, reducing the disease occurrence risk of the pavement and ensuring the service life of the pavement.
Description
Technical Field
The invention belongs to the technical field of indoor simulation tests of pavement materials, and particularly relates to an indoor aging simulation method based on the aging characteristic of a middle-layer material on an asphalt pavement.
Background
The asphalt pavement has the advantages of stable and comfortable driving, convenient repair, renewable utilization and the like, and is the preferred pavement type for road construction of all countries in the world at present. However, asphalt cements continue to age when exposed to complex environmental factors (e.g., high temperatures, ultraviolet radiation, atmospheric air, rain, etc.) during service. Meanwhile, the asphalt mixture layer adjacent to the pavement in the depth direction is less adversely affected by the absorption and obstruction environmental factors of the asphalt mixture layer at a certain depth position of the pavement, namely, the types and the strengths of factors causing the asphalt materials of different layers to age have larger difference. Therefore, after a certain service stage, the asphalt mixtures at different (depth) positions downward from the road surface have different aging degrees. According to the difference of aging factors and modes, the asphalt pavement can be divided into three layers from the surface of the road to the bottom. Wherein, the asphalt material in the first layer is exposed to solar radiation and fully contacted with the atmosphere and heat, and mainly undergoes thermal-oxidative aging and ultraviolet aging, so the aging degree is usually the maximum; the heat absorbed by the first layer of material is transferred downwards, but the heat is slowly diffused due to the fact that air in the pavement cannot flow, the heat is accumulated in the second layer, and due to the fact that air (oxygen) permeates from the outside, the asphalt material in the second layer mainly undergoes thermal-oxidative aging, and the aging degree is the next time; the bituminous material in the third layer is primarily thermally aged due to the slow transfer of heat from the second layer material. The influence of the aging factors on the asphalt material is attenuated layer by layer, so that the aging degree of the asphalt mixture below the third layer is weak. Finally, from the road surface to a certain depth, the aging degree of the asphalt mixture has a gradient descending rule.
The existing long-term aging indoor simulation method for the asphalt pavement material mainly refers to T0734 in road engineering asphalt and asphalt mixture test procedure JTG E20-2011 to perform long-term aging on an asphalt mixture, and specifically comprises the steps of compacting the loose mixture subjected to short-term aging to form a Marshall test piece, and then placing the Marshall test piece in an oven at 85 ℃ to age for 5 days; and after the aging test is finished, cooling the test piece to room temperature for testing. Therefore, the influence of solar radiation on the asphalt pavement material is neglected in the conventional long-term aging simulation method, and the actual meteorological data of an application field are not considered. Meanwhile, the gradient aging behavior characteristic of the asphalt pavement in the later service process is not considered.
Disclosure of Invention
In view of the above problems or defects in the prior art, the present invention is directed to an indoor aging simulation method based on the aging characteristics of the middle layer material on the asphalt pavement.
In order to realize the purpose of the invention, the technical scheme of the invention is as follows: an indoor aging simulation method based on the aging characteristic of a middle surface layer material on an asphalt pavement comprises the following steps:
s1: acquiring the annual average solar radiation R of an asphalt pavement application field to be researched ave And applying the average value of the maximum temperature of the field in the last 5 years to determine indoor aging simulation parameters;
s2: taking an upper layer and a middle layer of the asphalt pavement to be researched as research objects, taking the upper layer and the middle layer as a whole, and sequentially dividing the upper layer, the middle layer and the middle layer into a first layer material, a second layer material and a third layer material in a depth-down manner by taking the surface of the upper layer as a reference;
s3: respectively designing indoor accelerated aging test simulation conditions according to the aging conditions of the natural environment in which the first layer of material, the second layer of material and the third layer of material are positioned;
s4: and (4) respectively preparing a first layer material, a second layer material and a third layer material sample, then respectively carrying out an aging simulation test on each layer material sample under the indoor accelerated aging test simulation condition in the step (S3), and evaluating the aging resistance of the first layer material, the second layer material and the third layer material by extracting, recovering and testing the performance parameters of the asphalt cement in each layer material sample before and after the aging simulation test.
Further, the indoor aging simulation parameters in the step S1 include indoor aging simulation ultraviolet light aging intensity, ultraviolet light aging temperature, indoor electric heat blast oven aging temperature, and indoor accelerated aging duration.
Further, in the step S1, the annual average solar radiation amount is used to calculate and obtain the indoor ultraviolet light unit accelerated aging duration, and then the indoor accelerated aging duration is obtained based on the indoor ultraviolet light unit accelerated aging duration; the indoor ultraviolet unit accelerated aging time length = application field annual average solar radiation quantity x ultraviolet content/indoor ultraviolet radiation intensity; wherein, the ultraviolet radiation intensity is controlled by using a 500W high-pressure mercury lamp as an ultraviolet radiation light source and adjusting the distance between the sample and the light source; the ultraviolet light content is the proportion of the ultraviolet light energy in the solar radiation to the total energy of the solar radiation, and the content is in the range of 4-6%.
Further, in the step S2, according to the gradient aging behavior of the asphalt pavement, the thickness of the first layer of material accounts for 10% -25% of the sum of the thicknesses of the upper layer and the middle layer, the thickness of the second layer of material accounts for 20% -30% of the sum of the thicknesses of the upper layer and the middle layer, and the rest is the thickness of the third layer of material.
Further, in the step S3, an indoor accelerated aging test is performed on the first layer of material by irradiating the sample with an indoor ultraviolet lamp, and the indoor aging simulation ultraviolet irradiation intensity, the indoor ultraviolet aging temperature and the indoor accelerated aging duration are set; and the second layer material and the third layer material are subjected to an indoor accelerated aging test by using an electrothermal blowing oven, and the aging temperature and the indoor accelerated aging duration of the indoor oven are set.
Further, in the step S3:
the indoor accelerated ageing conditions of the first layer material were: the indoor aging simulated ultraviolet irradiation intensity is 60-400W/m 2 The indoor accelerated aging time is integral multiple of the indoor ultraviolet light unit accelerated aging time, the integral multiple range is 1-20, and the indoor ultraviolet light aging temperature is the average value of the highest temperature of the application field in the last 5 years plus 18 ℃;
the indoor accelerated aging conditions of the second layer of material were: heating by an electric heating air blast oven, wherein the indoor accelerated aging time is consistent with that of the first layer of material, and the indoor electric heating aging temperature is the average value of the maximum temperature of the application field in the last 5 years plus 20 ℃;
the indoor accelerated aging conditions of the third layer material are as follows: the electric heating air blast oven heats and covers a layer of iron plate or iron sheet outside the material, the indoor accelerated aging time is consistent with that of the first layer of material, and the indoor electric heating aging temperature is the average value of the maximum annual temperature of the application field in near 5 years plus 12 ℃.
Further, in step S4: the performance parameters comprise the softening point SP of the asphalt cement before and after aging unaged And SP aged Brookfield rotational viscosity V unaged And V aged And a complex modulus C obtained in a temperature scanning mode based on a dynamic shear rheometer unaged And C aged And phase angle PA unaged And PA aged And obtaining the softening point increment SPI, the Brinell rotation viscosity change rate VAI, the complex modulus change rate CAI and the phase angle change rate PAI before and after the asphalt cement in each layer of material is aged based on the performance parameters, and evaluating the aging resistance of each layer of material.
Further, the step S4 specifically includes the following steps:
(a) Preparing each layer of loose materials and simulating indoor short-term aging: respectively preparing a first layer material, a second layer material and a third layer material according to the composition characteristics of the middle surface layer material on the asphalt pavement to be researched, and then taking the materials of each layer at a ratio of 21-22 kg/m 2 The loose paving density is respectively put into an electric heating blast oven with the temperature of 135 ℃ for forced ventilation for 4 hours, and a shovel is used for stirring once per hour so as to simulate the aging of the asphalt mixture in the actual stirring, production and transportation processes;
(b) Preparing each layer of asphalt concrete material: respectively forming a first layer of material, a second layer of material and a third layer of material by using the sample obtained in the step (a) through a wheel milling method, wherein the thicknesses of the first layer of material, the second layer of material and the third layer of material meet the layered thickness designed in the step S2, and meanwhile, the compactness of each layer of material is consistent with that of the middle layer of the asphalt pavement to be researched, so that a first layer of asphalt concrete sample, a second layer of asphalt concrete sample and a third layer of asphalt concrete sample are respectively obtained;
(c) Aging of materials of each layer: aging each layer of asphalt concrete sample prepared in the step (b) according to the indoor accelerated aging test simulation conditions in the step S3 respectively to obtain a first layer of asphalt mixture, a second layer of asphalt mixture and a third layer of asphalt mixture after indoor accelerated aging;
(d) And (3) extracting, recovering and testing the aged sample: respectively extracting and recovering asphalt cement in each layer of asphalt mixture obtained before and after the step (c) by using a rotary evaporator method according to T0727 in the reference procedure, and then testing the softening point (according to the procedure T0606), the Brookfield rotary viscosity (according to the procedure T0625) and the temperature scanning (according to the procedure T0628) of the asphalt cement recovered before and after the aging of each layer of material to obtain the softening point SP unaged And SP aged Brookfield rotational viscosity V unaged And V aged And a complex modulus C obtained in a temperature scanning mode based on a dynamic shear rheometer unaged And C aged And phase angle PA unaged And PA aged Respectively calculating the softening point increment SPI = SP of the asphalt cement in the first layer material, the second layer material and the third layer material based on the parameters aged －SP unaged And the Brinell rotational viscosity change ratio VAI = V aged ÷V unaged Complex modulus change rate CAI = C aged ÷C unaged And phase angle rate of change PAI = PA aged ÷PA unaged Evaluating the physical aging performance of each layer of material through softening point increment SPI and Brinell rotation viscosity change rate VAI; the rheological ageing properties of the materials of the various layers are evaluated by the complex modulus change rate CAI and the phase angle change rate PAI.
Compared with the prior art, the invention has the following beneficial effects:
the invention establishes the indoor simulated aging environment of different layer materials of the application field based on the gradient aging behavior characteristics of different layer materials of the asphalt pavement and the application field meteorological data as the basis of the indoor aging simulation parameter selection, aiming at the factors and aging mode characteristics causing the aging of the asphalt materials of each layer, so as to better simulate and find the performance evolution law of the materials in the actual service process, thereby verifying the service performance of the asphalt pavement materials to be applied. The method has important significance for expanding the indoor simulation method of the asphalt pavement material, improving the performance verification and application efficiency of the novel pavement material, saving the construction investment of the asphalt pavement, reducing the disease occurrence risk of the pavement and ensuring the service life of the pavement.
Drawings
These and/or other aspects and advantages of the present invention will become more apparent and more readily appreciated from the following detailed description of the embodiments of the invention, taken in conjunction with the accompanying drawings of which:
FIG. 1 is a schematic flow chart of an indoor aging simulation method based on the aging characteristics of medium surface layer materials on an asphalt pavement.
Detailed Description
In order that those skilled in the art will better understand the present invention, the following detailed description of the invention is provided in conjunction with the accompanying drawings and the detailed description of the invention.
Example 1:
an indoor aging simulation method based on the aging characteristic of a middle layer material on an asphalt pavement in an inner Mongolia region is characterized in that the middle layer material is in the middle of the outer part of the inland plateau, is in the Gobi region of the inland plateau desert, and is a typical continental climate. The area is dry and rainy, has more cloudy days all the year round, has good atmosphere transparency, is hot in summer and cold in winter, has large temperature difference between day and night, and has the annual average temperature of 6-8.5 ℃. The average temperature is minus 9 to 14 ℃ in 1 month, and the extreme lowest temperature is minus 36.4 ℃; the average temperature of the solution is 22-26.4 ℃ in 7 months. The average value of the extreme maximum temperature in the last 5 years is 41.7 ℃. The annual sunshine hours in the area are about 2900-3500 hours, and the annual total solar radiation is about 7000MJ/m 2 。
The flow schematic of the indoor aging simulation method based on the aging characteristic of the medium-surface layer material on the asphalt pavement in the inner Mongolia region is shown in figure 1, and the method comprises the following steps:
(1) The designed pavement thickness of a highway in service for 5 years in the area is as follows: the thickness of the upper layer is 4cm, and the thickness of the middle layer is 6cm; taking a proper amount of raw materials used in the road construction process for subsequent tests and tests, wherein the sample raw materials comprise coarse aggregates, fine aggregates, asphalt cement, mineral powder, modifier and the like, and randomly taking a certain amount of samples from the drill cores of the existing service pavements.
(2) Carrying out layering and anti-aging design on materials used for the upper layer and the middle layer of the pavement: the first layer is 0-2 cm below the road surface, the second layer is 2-5 cm below the road surface, and the third layer is 5-10 cm below the road surface.
(3) According to the meteorological data of the asphalt pavement application field to be researched, the indoor simulated aging test and the parameters of the first layer material are as follows: the 500W high-pressure mercury lamp is used as an ultraviolet radiation light source, and the ultraviolet radiation intensity of the sample is controlled to be 375W/m by adjusting the distance between the sample and the light source 2 The sample photo-oxygen aging temperature is 41.7 (the highest temperature) +18 ℃ and is approximately equal to 60 ℃, and the annual average ultraviolet radiation energy equivalent indoor ultraviolet light accelerated aging time length is 7000MJ/m 2 ×6％/375W/m 2 Room photo-oxygen aging acceleration test of 5 units (5 × 305h = 1525h) was carried out for 305 h;
the indoor accelerated aging test of the second layer material and the parameters thereof are as follows: an electric heating air blast oven is adopted for carrying out an accelerated aging test, the aging temperature is 41.7+20 ≈ 62 ℃, and the indoor thermal oxygen aging accelerated aging time is 1525h;
the indoor accelerated aging test and parameters of the third layer material and the control group thereof are as follows: the sample is put into a tray, a layer of iron plate is covered on the tray, and then the tray is put into an electric heating air-blowing oven for aging, the aging temperature is 41.7+12 ≈ 54 ℃, and the indoor thermal aging accelerated aging time is 1525h.
(4) Respectively preparing loose asphalt mixture of each layer according to the composition characteristics of the medium surface layer material on the asphalt pavement to be researched, and then taking a proper amount of loose materials of each layer at the ratio of 21-22 kg/m 2 The loose pavement densities are respectively put into an electric heating blast oven with the temperature of 135 ℃ for forced ventilation for 4 hours, and a shovel is used for turning and stirring once per hour.
And (3) molding each layer of material of the prepared loose asphalt mixture by adopting a wheel rolling method, wherein the thickness of the molded first layer of material is 2cm, the thickness of the molded second layer of material is 3cm, the thickness of the molded third layer of material is 5cm, and the compactness of each layer of material is consistent with that of the middle layer of the asphalt pavement to be researched.
Taking a proper amount of the formed first layer material and putting the first layer material into the die to form a first layer of die with the thickness of 375W/m 2 Carrying out an indoor photo-oxidative aging accelerated experiment with the duration of 1525h in a photo-oxidative aging box at the temperature of 60 ℃; at the same time, take the right amountPlacing the molded second layer material into an electric heating air blowing oven at 62 ℃ to carry out an indoor thermal oxidation aging acceleration experiment for 1525h; and (3) putting a proper amount of the formed third layer material into a tray, covering a layer of iron plate on the tray, and then putting the tray into an electrothermal blowing oven at 54 ℃ for an indoor thermal aging acceleration experiment with the time length of 1525h.
After the aging test is finished, extracting and recovering asphalt cement in the asphalt mixture before and after aging by using a rotary evaporator method, and performing softening point, brookfield rotary viscosity and temperature scanning tests on the recovered asphalt cement, wherein the specific test results are shown in table 1. And then, respectively calculating the performance difference or change rate of the asphalt cement after aging and before aging, and finally obtaining a physical aging index (softening point increment SPI and Brookfield rotary viscosity change rate VAI) and a rheological aging index (complex modulus change rate CAI and phase angle change rate PAI) as shown in Table 2, so as to analyze the aging resistance of each layer of material and the aging resistance difference among the layers of material. On the other hand, samples obtained by core drilling sampling are extracted and recovered layer by layer according to the layering method to carry out corresponding tests and calculations, and the specific test results and the calculation results of the aging index are shown in tables 1 and 2 respectively.
As can be seen from tables 1 and 2, similar to in situ aging of a pavement, the indoor simulated aging environment increases the softening point, viscosity, and complex modulus of the asphalt material but decreases the phase angle of the asphalt material. Meanwhile, the performances and physical and rheological aging indexes of the asphalt material subjected to specific indoor simulated aging and pavement in-situ aging are relatively close, which shows that the indoor simulated aging conditions of each layer of material are reasonable, and the aging effect of each layer of material of the asphalt pavement in the service process can be effectively simulated. In addition, the physical and complex modulus index of the first layer of material is highest, the second layer of material is next to that of the second layer of material, the third layer of material is lowest, the phase angle aging index results are just opposite, the gradient aging behavior characteristic of the pavement material is verified, and the aging resistance difference among the materials of the layers is also determined.
If the indoor simulated aging result shows that: in softening point increment, the first layer of material is 1.0 ℃ higher than the second layer of material, and the first layer of material is 1.4 ℃ higher than the third layer of material; the viscosity aging index of the first layer material is 21.43 percent higher than that of the second layer material, and the viscosity aging index of the first layer material is 30.95 percent higher than that of the third layer material; the first layer of material is 18.00 percent higher than the second layer of material and the first layer of material is 24.89 percent higher than the third layer of material in terms of complex modulus aging index; the first layer material was 2.67% lower than the second layer material and the first layer material was 5.53% lower than the third layer material in the phase angle aging index.
Table 1 example 1 results of testing the properties of asphalt materials of each layer at different aging stages and aging environments
TABLE 2 physical and rheological aging indices of various layers of bituminous materials under different aging environments in example 1
Example 2:
the Changsha city is located in the northeast of the east of Hunan province, at the downstream of Xiangjiang river and at the west edge of the long Liu basin, and has the climate characteristics that: subtropical monsoon humid climate, cold winter and hot summer, clear four seasons, short spring and autumn, and long winter and summer. The average temperature of the sand growing region is 17.1 ℃ for many years, the temperature is coldest in 1 month, and the average temperature is 4.8 ℃; the hottest in 7 months and the average temperature of 28.8 ℃. The average value of the extreme maximum temperature in the last 5 years is 41.1 ℃. The annual average total solar radiation is about 5000MJ/m 2 The average sunshine number of years is 1500h.
An indoor aging simulation method based on the aging characteristics of medium surface layer materials on asphalt pavements in long sand areas comprises the following steps:
(1) The designed pavement thickness of a certain 8-year-on-service expressway in the area is as follows: the thickness of the upper layer is 4cm, and the thickness of the middle layer is 5cm; taking a proper amount of raw materials used in the road construction process for subsequent tests and tests, wherein the sample raw materials comprise coarse aggregates, fine aggregates, asphalt cement, mineral powder, modifier and the like, and randomly taking a certain amount of samples from the drill cores of the existing service pavements.
(2) Carrying out layering and anti-aging design on materials used for the upper surface layer and the middle surface layer of the pavement: the first layer is 0-2 cm below the road surface, the second layer is 2-4 cm below the road surface, and the third layer is 5-9 cm below the road surface.
(3) According to the meteorological data of the asphalt pavement application field to be researched, the indoor aging simulation parameters of the first layer of material are as follows: a 500W high-pressure mercury lamp is used as an ultraviolet radiation light source, and the ultraviolet radiation intensity of the sample is controlled to be 300W/m by adjusting the distance between the sample and the light source 2 The sample photo-oxygen aging temperature is 41.1 (highest air temperature) +18 ℃ and is approximately equal to 59 ℃, the annual average ultraviolet radiation energy equivalent indoor ultraviolet light accelerated aging time length is 5000MJ/m 2 ×6％/300W/m 2 In 8 units (8 × 278h = 2224h), room photo-oxidative aging acceleration test was performed for =278 h.
The indoor accelerated aging test of the second layer material and the parameters thereof are as follows: and putting the two groups of asphalt mixture samples into trays respectively, and then putting the two groups of asphalt mixture samples into an electric heating air-blowing oven for aging at the aging temperature of 41.1+20 ≈ 61 ℃ for 2224h under indoor thermal-oxygen aging acceleration.
The indoor accelerated aging test and the parameters of the third layer material are as follows: the two groups of asphalt mixture samples are respectively put into trays, a layer of iron plate is covered on the trays, and then the trays are put into an electric heating air-blowing oven for aging, the aging temperature is 41.1+12 ≈ 53 ℃, and the indoor thermal aging accelerated aging time is 2224h.
(4) Respectively preparing each layer of loose asphalt mixture according to the composition characteristics of the medium surface layer material on the asphalt pavement to be researched, and then taking a proper amount of each layer of loose materials at a ratio of 21-22 kg/m 2 The loose mat density is put into an electric heating blast oven with the temperature of 135 ℃ for forced ventilation for 4 hours, and the loose mat is turned and stirred once per hour by a shovel.
And (3) molding each layer of material of the prepared loose asphalt mixture by adopting a wheel milling method, wherein the thickness of the molded first layer of material is 2cm, the thickness of the molded second layer of material is 2cm, the thickness of the molded third layer of material is 4cm, and the compactness of each layer of material is consistent with that of the middle layer of the asphalt pavement to be researched.
Taking a proper amount of the formed first layer material and putting the first layer material into a container with the volume of 300W/m 2 And the light oxygen aging box at 59 DEG CIndoor photo-oxygen aging accelerated experiment with the line duration of 2224 h; placing a proper amount of the formed second layer material into an electric heating air blowing oven at 61 ℃ to perform an indoor accelerated thermal oxidation aging experiment for 2224 h; and (3) putting a proper amount of the formed third layer material into a tray, covering a layer of iron plate on the tray, and then putting the tray into a 53-DEG C electric heating air blowing oven to perform indoor accelerated thermal aging experiment for 2224h.
After the aging test is finished, extracting and recovering asphalt cement in the asphalt mixture before and after aging by using a rotary evaporator method, and performing softening point, brookfield rotary viscosity and temperature scanning tests on the recovered asphalt cement, wherein the specific test results are shown in table 3. And then, respectively calculating the performance difference or change rate of the asphalt cement after aging and before aging, and finally obtaining a physical aging index (softening point increment SPI and Brookfield rotary viscosity change rate VAI) and a rheological aging index (complex modulus change rate CAI and phase angle change rate PAI) as shown in Table 4, so as to analyze the aging resistance of each layer of material and the aging resistance difference among the layers of material. On the other hand, samples obtained by core drilling sampling are extracted and recovered layer by layer of the on-site aged cementing material according to the layering method and are subjected to corresponding tests, and specific test results and aging indexes are respectively shown in tables 3 and 4.
From tables 3 and 4, it can be seen that the indoor simulated aging environment increases the softening point, viscosity, and complex modulus of the asphalt material but decreases the phase angle of the asphalt material, similar to in situ aging of the pavement. Meanwhile, the performances and physical and rheological aging indexes of the asphalt material subjected to specific indoor simulated aging and pavement in-situ aging are relatively close to each other, which shows the reasonability of indoor simulated aging condition setting of each layer of material and can effectively simulate the aging effect of each layer of material of the asphalt pavement in the service process. In addition, the physical and complex modulus index of the first layer of material is the highest, the second layer of material is the next to the second layer of material, the third layer of material is the lowest, the phase angle aging index results are just opposite, the gradient aging behavior characteristic of the pavement material is verified, and the aging resistance difference among the materials of all layers is also determined.
If the indoor simulated aging result shows that: in softening point increment, the first layer of material is 0.7 ℃ higher than the second layer of material, and the first layer of material is 1.5 ℃ higher than the third layer of material; the viscosity aging index of the first layer material is 18.08 percent higher than that of the second layer material, and the viscosity aging index of the first layer material is 39.22 percent higher than that of the third layer material; the first layer material is 34.37% higher than the second layer material and the first layer material is 71.92% higher than the third layer material in terms of complex modulus aging index; the first layer material was 1.01% lower than the second layer material and the first layer material was 1.10% lower than the third layer material in the phase angle aging index.
Table 3 example 2 results of performance testing of asphalt materials of each layer at different aging stages and aging environments
TABLE 4 physical and rheological aging indices of various layers of bituminous materials under different aging environments in example 2
Example 3:
the adult cities are in southwest areas of China, the west of Sichuan basins, junior plains, abdominal areas and domestic areas, belong to subtropical monsoon humid climates, and have the climatic characteristics of early spring, hot summer, cool autumn and warm winter. The average temperature of 1 month is 6.2 ℃, and the extreme lowest temperature is-1.5 ℃; the average temperature is 25.8 ℃ in 7 months. The average value of the extreme maximum temperature in the last 5 years is 38.4 ℃. The annual sunshine hours in the area are about 1000 hours, and the annual total solar radiation is about 3000MJ/m 2 。
An indoor aging simulation method based on aging characteristics of medium-sized surface layer materials on asphalt pavements in Chengdu areas comprises the following steps:
(1) The designed pavement thickness of a highway which is in service for 5 years in the area is as follows: the thickness of the upper layer is 4cm, and the thickness of the middle layer is 5cm; taking a proper amount of raw materials used in the road construction process for subsequent tests and tests, wherein the sample raw materials comprise coarse aggregates, fine aggregates, asphalt cement, mineral powder, modifier and the like, and randomly taking a certain amount of samples from the drill cores of the existing service pavements.
(2) Carrying out layering and anti-aging design on materials used for the upper layer and the middle layer of the pavement: the first layer is 0-2 cm below the road surface, the second layer is 2-4 cm below the road surface, and the third layer is 4-9 cm below the road surface.
(3) According to meteorological data of an asphalt pavement application field to be researched, indoor aging simulation parameters of the first layer material are as follows: the 500W high-pressure mercury lamp is used as an ultraviolet radiation light source, and the ultraviolet radiation intensity of the sample is controlled to be 200W/m by adjusting the distance between the sample and the light source 2 The sample photo-oxygen aging temperature is 38.4 (highest temperature) +18 ℃ and is approximately equal to 57 ℃, and the annual average ultraviolet radiation energy equivalent indoor ultraviolet light accelerated aging time length is 3000MJ/m 2 ×6％/200W/m 2 5 units (5 × 250h = 1250h) indoor photo-oxygen aging acceleration experiment is carried out;
the indoor accelerated aging parameters of the second layer of material were: placing two groups of asphalt mixture samples into trays respectively, and then placing the trays into an electric heating blowing oven for aging at the aging temperature of 38.4+20 ≈ 59 ℃ for 1250h;
the indoor accelerated aging parameters of the third layer material are as follows: the two groups of asphalt mixture samples are respectively put into trays, a layer of iron plate is covered on the trays, and then the two groups of asphalt mixture samples are put into an electric heating air-blowing oven for aging at the aging temperature of 38.4+12 ≈ 51 ℃ for indoor thermal aging accelerated aging time of 1250h.
(4) Respectively preparing each layer of loose asphalt mixture according to the composition characteristics of the medium surface layer material on the asphalt pavement to be researched, and then taking a proper amount of each layer of loose materials at a ratio of 21-22 kg/m 2 The loose mat density is put into an electric heating blast oven with the temperature of 135 ℃ for forced ventilation for 4 hours, and the loose mat is turned and stirred once per hour by a shovel.
And (3) molding each layer of material of the prepared loose asphalt mixture by adopting a wheel milling method, wherein the thickness of the molded first layer of material is 2cm, the thickness of the molded second layer of material is 2cm, the thickness of the molded third layer of material is 5cm, and the compactness of each layer of material is consistent with that of the middle layer of the asphalt pavement to be researched.
Taking a proper amount of the formed first layer material and putting the first layer material into a container with the volume of 200W/m 2 When carried out in a light-oxygen aging oven at 57 DEG CAn indoor photo-oxidation aging acceleration experiment with the length of 1250h; meanwhile, taking a proper amount of the formed second layer material, and putting the second layer material into an electrothermal blowing oven at 59 ℃ to perform an indoor thermal oxygen aging acceleration experiment with the duration of 1250h; and (3) putting a proper amount of the formed third layer material into a tray, covering a layer of iron plate on the tray, and putting the tray into a 51 ℃ electric heating air blowing oven to perform an indoor heat aging acceleration experiment with the time length of 1250h.
After the aging test is finished, extracting and recovering asphalt cement in the asphalt mixture before and after aging by using a rotary evaporator method, and performing softening point, brookfield rotary viscosity and temperature scanning tests on the recovered asphalt cement, wherein the specific test results are shown in table 5. And then calculating the performance change value or change rate of the asphalt cement after aging and before aging respectively, and finally obtaining a physical aging index (softening point increment SPI and Brookfield rotary viscosity change rate VAI) and a rheological aging index (complex modulus change rate CAI and phase angle change rate PAI) as shown in table 6 so as to analyze the aging resistance of each layer of material and the aging resistance difference between each layer of material. On the other hand, samples obtained by core drilling sampling are extracted and recovered layer by layer of the field aged cementing material according to the layering method, and corresponding tests are carried out, wherein the specific test results are shown in tables 5 and 6 respectively.
From tables 5 and 6, it can be seen that the indoor simulated aging environment increases the softening point, viscosity, and complex modulus of the asphalt material but decreases the phase angle of the asphalt material, similar to in situ aging of the pavement. Meanwhile, the performances and physical and rheological aging indexes of the asphalt material subjected to specific indoor simulated aging and pavement in-situ aging are relatively close to each other, which shows the reasonability of indoor simulated aging condition setting of each layer of material and can effectively simulate the aging effect of each layer of material of the asphalt pavement in the service process. In addition, the physical and complex modulus index of the first layer of material is the highest, the second layer of material is the next to the second layer of material, the third layer of material is the lowest, the phase angle aging index results are just opposite, the gradient aging behavior characteristic of the pavement material is verified, and the aging resistance difference among the materials of all layers is also determined.
If the indoor simulation aging result shows that: in the softening point increment, the first layer of material is 1.6 ℃ higher than the second layer of material, and the first layer of material is 2.1 ℃ higher than the third layer of material; the viscosity aging index of the first layer of material is 23.8 percent higher than that of the second layer of material, and the viscosity aging index of the first layer of material is 50.7 percent higher than that of the third layer of material; in complex modulus aging index, the first layer material is 30.8% higher than the second layer material, and the first layer material is 83.6% higher than the third layer material; the first layer of material was 5.0% lower than the second layer of material and the first layer of material was 7.9% lower than the third layer of material at the phase angle aging index.
Table 5 example 3 results of testing the properties of asphalt materials of each layer at different aging stages and aging environments
TABLE 6 physical and rheological aging indices of various layers of bituminous materials under different aging environments in example 3
Having described embodiments of the present invention, the foregoing description is intended to be exemplary, not exhaustive, and not limited to the embodiments disclosed. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the described embodiments. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.
Claims (8)
1. An indoor aging simulation method based on the aging characteristic of a middle surface layer material on an asphalt pavement is characterized by comprising the following steps:
s1: acquiring the annual average solar radiation R of an asphalt pavement application field to be researched ave And applying the average value of the maximum temperature of the field in the last 5 years to determine indoor aging simulation parameters;
s2: taking an upper layer and a middle layer of the asphalt pavement to be researched as research objects, taking the upper layer and the middle layer as a whole, and sequentially dividing the upper layer, the middle layer and the middle layer into a first layer material, a second layer material and a third layer material in a depth-down manner by taking the surface of the upper layer as a reference;
s3: respectively designing indoor accelerated aging test simulation conditions according to the aging conditions of the natural environment in which the first layer of material, the second layer of material and the third layer of material are positioned;
s4: and (4) respectively preparing a first layer material, a second layer material and a third layer material sample, then respectively carrying out a simulated aging test on each layer material sample under the indoor accelerated aging test simulation condition in the step (S3), and evaluating the aging resistance of the first layer material, the second layer material and the third layer material by extracting, recovering and testing the performance parameters of the asphalt cement in each layer material sample before and after the simulated aging test.
2. The indoor aging simulation method based on the aging characteristics of the middle-surface-layer material on the asphalt pavement according to claim 1, wherein the indoor aging simulation parameters in the step S1 include indoor aging simulation ultraviolet light aging intensity, ultraviolet light aging temperature, indoor electric heat blast oven aging temperature and indoor accelerated aging duration.
3. The indoor aging simulation method based on the aging characteristics of the middle-surface layer material on the asphalt pavement according to claim 2, wherein in the step S1, the unit accelerated aging duration of indoor ultraviolet light is obtained by calculation using the annual average solar radiation amount, and then the unit accelerated aging duration of indoor ultraviolet light is obtained based on the unit accelerated aging duration of indoor ultraviolet light; the indoor ultraviolet unit accelerated aging time length = the annual average solar radiation quantity of an application field multiplied by the ultraviolet content/indoor ultraviolet radiation intensity; wherein, the ultraviolet radiation intensity is controlled by using a 500W high-pressure mercury lamp as an ultraviolet radiation light source and adjusting the distance between the sample and the light source; the ultraviolet light content is the proportion of the total energy of the solar radiation in the solar radiation, and the content is in the range of 4-6%.
4. The indoor aging simulation method based on the aging characteristic of the middle surface layer material on the asphalt pavement according to claim 3, wherein in the step S2, according to the gradient aging behavior characteristic of the asphalt pavement, the thickness of the first layer material accounts for 10% -25% of the sum of the thicknesses of the upper layer and the middle surface layer, the thickness of the second layer material accounts for 20% -30% of the sum of the thicknesses of the upper layer and the middle surface layer, and the rest is the thickness of the third layer material.
5. The method for simulating indoor aging based on the aging characteristic of the middle-surface-layer material on the asphalt pavement according to claim 4, wherein in the step S3, the first-layer material is subjected to an indoor accelerated aging test by irradiating a sample with an indoor ultraviolet lamp, and the indoor aging simulation ultraviolet irradiation intensity, the indoor ultraviolet aging temperature and the indoor accelerated aging duration are set; and the second layer material and the third layer material are subjected to an indoor accelerated aging test by using an electrothermal blowing oven, and the aging temperature and the indoor accelerated aging duration of the indoor oven are set.
6. The indoor aging simulation method based on the aging characteristics of the medium surface layer material on the asphalt pavement according to claim 1, characterized in that in the step S3:
the indoor accelerated ageing conditions of the first layer material were: the indoor aging simulation ultraviolet irradiation intensity is 60-400W/m 2 The indoor accelerated aging time is an integral multiple of the indoor ultraviolet light unit accelerated aging time, the integral multiple range is 1-20, and the indoor ultraviolet light aging temperature is the average value of the annual maximum temperature of the application field in the last 5 years plus 18 ℃;
the indoor accelerated aging conditions of the second layer of material were: heating by an electric heating air blast oven, wherein the indoor accelerated aging time is consistent with that of the first layer of material, and the indoor electric heating aging temperature is the average value of the maximum temperature of the application field in 5 years and 20 ℃ every year;
the indoor accelerated aging conditions of the third layer material are as follows: an electric heating air blast oven heats and covers a layer of iron plate or iron sheet outside the material, the indoor accelerated aging time is consistent with that of the first layer of material, and the indoor electric heating aging temperature is the average value of the maximum annual temperature of the application field in nearly 5 years plus 12 ℃.
7. The indoor aging simulation method based on the aging characteristics of the middle-surface layer material on the asphalt pavement according to claim 6, characterized in that in step S4: the performance parameters comprise the softening point SP of the asphalt cement before and after aging unaged And SP aged Brookfield rotational viscosity V unaged And V aged And a complex modulus C obtained in a temperature scanning mode based on a dynamic shear rheometer unaged And C aged And phase angle PA unaged And PA aged And obtaining the increment SPI of the softening point, the VAI of the Brookfield rotary viscosity, the CAI of the complex modulus and the PAI of the phase angle before and after the asphalt cement in each layer of material is aged based on the performance parameters, and evaluating the aging resistance of each layer of material.
8. The indoor aging simulation method based on the aging characteristics of the middle-surface layer material on the asphalt pavement according to claim 7, wherein the step S4 specifically comprises the following steps:
(a) Preparing each layer of loose materials and simulating indoor short-term aging: respectively preparing a first layer material, a second layer material and a third layer material according to the composition characteristics of the middle surface layer material on the asphalt pavement to be researched, and then taking the materials of each layer at a ratio of 21-22 kg/m 2 The loose pavement density is respectively put into an electric heating blast oven with the temperature of 135 ℃ for forced ventilation for 4 hours, and a shovel is used for stirring once per hour so as to simulate the aging of the asphalt mixture in the actual stirring, production and transportation processes;
(b) Preparing each layer of asphalt concrete material: respectively forming a first layer of material, a second layer of material and a third layer of material by using the sample obtained in the step (a) through a wheel milling method, wherein the thicknesses of the first layer of material, the second layer of material and the third layer of material meet the layered thickness designed in the step S2, and meanwhile, the compactness of each layer of material is consistent with that of the middle layer of the asphalt pavement to be researched, so that a first layer of asphalt concrete sample, a second layer of asphalt concrete sample and a third layer of asphalt concrete sample are respectively obtained;
(c) Aging of each layer of material: aging each layer of asphalt concrete sample prepared in the step (b) according to the indoor accelerated aging test simulation conditions in the step S3 respectively to obtain a first layer of asphalt mixture, a second layer of asphalt mixture and a third layer of asphalt mixture after indoor accelerated aging;
(d) Extracting and recovering an aged sample and testing the performance of the aged sample by respectively extracting and recovering asphalt cement in each layer of asphalt mixture obtained before and after the step (c) by using a rotary evaporator method, and then performing softening point, brookfield rotary viscosity and temperature scanning tests on the asphalt cement recovered before and after the aging of each layer of material to obtain a softening point SP unaged And SP aged Brookfield rotational viscosity V unaged And V aged And a complex modulus C obtained in a temperature scanning mode based on a dynamic shear rheometer unaged And C aged And phase angle PA unaged And PA aged Respectively calculating the softening point increment SPI, the Brinell rotational viscosity change rate VAI, the complex modulus change rate CAI and the phase angle change rate PAI of the asphalt cement in the first layer material, the second layer material and the third layer material based on the parameters, and evaluating the physical aging performance of each layer of material through the softening point increment SPI and the Brinell rotational viscosity change rate VAI; the rheological ageing properties of the materials of the various layers are evaluated by the complex modulus change rate CAI and the phase angle change rate PAI.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202211156310.3A CN115615909B (en) | 2022-09-22 | 2022-09-22 | Indoor aging simulation method based on aging characteristics of middle surface layer material on asphalt pavement |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202211156310.3A CN115615909B (en) | 2022-09-22 | 2022-09-22 | Indoor aging simulation method based on aging characteristics of middle surface layer material on asphalt pavement |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN115615909A true CN115615909A (en) | 2023-01-17 |
| CN115615909B CN115615909B (en) | 2023-06-20 |
Family
ID=84859651
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202211156310.3A Active CN115615909B (en) | 2022-09-22 | 2022-09-22 | Indoor aging simulation method based on aging characteristics of middle surface layer material on asphalt pavement |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN115615909B (en) |
Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE102010050682A1 (en) * | 2010-11-06 | 2012-05-10 | Dr. Ing. Löffler Consulting und Engineering Baustoffprüfung und Umwelt GmbH | Device for conditioning open-pore asphalt for road surface on specimen in water treatment plant, has holder unit and manipulator connected over guidance system that comprises guide surfaces aligned parallel to working plane |
| CN103146207A (en) * | 2013-03-19 | 2013-06-12 | 湖北国创高新材料股份有限公司 | Ultraviolet aging-resistant compound modified asphalt and preparation method thereof |
| CN105043964A (en) * | 2015-07-16 | 2015-11-11 | 哈尔滨工业大学 | Test apparatus for ultraviolet aging acceleration of asphalt-based materials |
| CN107652700A (en) * | 2017-10-31 | 2018-02-02 | 宁夏路桥工程股份有限公司 | The preparation method of durability modified pitch |
| CN111307702A (en) * | 2020-04-15 | 2020-06-19 | 长安大学 | Method for simulating long-term aging of asphalt pavement |
| CN112683767A (en) * | 2020-12-24 | 2021-04-20 | 南京林业大学 | Asphalt indoor aging method under heat-light-water coupling circulation effect |
-
2022
- 2022-09-22 CN CN202211156310.3A patent/CN115615909B/en active Active
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE102010050682A1 (en) * | 2010-11-06 | 2012-05-10 | Dr. Ing. Löffler Consulting und Engineering Baustoffprüfung und Umwelt GmbH | Device for conditioning open-pore asphalt for road surface on specimen in water treatment plant, has holder unit and manipulator connected over guidance system that comprises guide surfaces aligned parallel to working plane |
| CN103146207A (en) * | 2013-03-19 | 2013-06-12 | 湖北国创高新材料股份有限公司 | Ultraviolet aging-resistant compound modified asphalt and preparation method thereof |
| CN105043964A (en) * | 2015-07-16 | 2015-11-11 | 哈尔滨工业大学 | Test apparatus for ultraviolet aging acceleration of asphalt-based materials |
| CN107652700A (en) * | 2017-10-31 | 2018-02-02 | 宁夏路桥工程股份有限公司 | The preparation method of durability modified pitch |
| CN111307702A (en) * | 2020-04-15 | 2020-06-19 | 长安大学 | Method for simulating long-term aging of asphalt pavement |
| CN112683767A (en) * | 2020-12-24 | 2021-04-20 | 南京林业大学 | Asphalt indoor aging method under heat-light-water coupling circulation effect |
Non-Patent Citations (1)
| Title |
|---|
| 屈鑫 等: "道路沥青老化评价方法研究进展", 《中国公路学报》, vol. 35, no. 6, pages 205 - 220 * |
Also Published As
| Publication number | Publication date |
|---|---|
| CN115615909B (en) | 2023-06-20 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN111548057B (en) | Mix proportion design method of plant-mixed hot recycled asphalt mixture | |
| CN105601176B (en) | A kind of hot in-plant reclaimed asphalt concrete production method | |
| CN101387097B (en) | Porous thermal conductive asphalt concrete pavement heat exchange system and use thereof | |
| CN106007491B (en) | Normal-temperature regeneration asphalt and preparation method thereof | |
| CN105837090A (en) | High-addition-amount plant-mixed warm regenerated asphalt mixture and preparation method thereof | |
| CN111960727B (en) | Design method of high-mixing-amount anti-fatigue regenerated asphalt mixture | |
| CN104326701A (en) | Preparation method and performance evaluation method of ultraviolet aging resistant asphalt mixture | |
| CN103482924B (en) | Water-retaining and cooling pavement material and application thereof | |
| Mingyu et al. | Effects of conductive fillers on temperature distribution of asphalt pavements | |
| CN111170678A (en) | Pouring type concrete with polyurethane as binder and preparation method thereof | |
| CN115615909B (en) | Indoor aging simulation method based on aging characteristics of middle surface layer material on asphalt pavement | |
| CN103739872A (en) | Waste SBS (Styrene Butadiene Styrene) modified asphalt recycling method | |
| CN104819912B (en) | A kind of asphalt foaming determination method for parameter | |
| CN106927731A (en) | A kind of morning strong high-durability cold recycled asphalt mixture and preparation method thereof | |
| CN112094078A (en) | Preparation method of plant-mixed hot recycled asphalt mixture | |
| Okunade | Engineering properties of locally manufactured burnt brick pavers for Agrarian and rural earth roads | |
| CN103290757A (en) | Blending method of hot mix plant recycling bituminous mixtures | |
| CN114573272B (en) | Regeneration method for microwave heating activation of old asphalt mixture | |
| CN114014591A (en) | Phase-change temperature self-adjusting asphalt mixture for roads and preparation method thereof | |
| CN108395182B (en) | Composite heat-storage temperature-control ecological base material and preparation method thereof | |
| Han et al. | Low-temperature performance test method and improvement measures of emulsified asphalt cold recycling mixture | |
| Norambuena-Contreras et al. | Novel bituminous materials for sustainable pavements | |
| CN115231857B (en) | Method for improving aging performance of asphalt pavement material through layered modification | |
| CN110607078A (en) | Preparation method and application of high-performance road biological asphalt | |
| Zhang et al. | The Research on Aging Performance of Rubber Asphalt Based on Laboratory Test |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |