Method and system for detecting aggregate pulverization in asphalt mixture

Abstract

The application discloses a kind of detection methods and systems of aggregate pulverization in asphalt mixture, to obtain the pulverization degree trend of grade asphalt mixture in the use process of asphalt pavement, improve the judgment precision whether mineral aggregate in asphalt mixture is pulverized, prevent mineral aggregate from causing early damage of asphalt mixture pavement due to pulverization;Among them, the method comprises: preparing asphalt mixture mineral aggregate sample according to preset proportioning;Obtain the average value of the particle content of the preset particle size therein;Prepare Marshall test piece, obtain first sample by heating device;Respectively remove asphalt in first sample, obtain second sample and its mass average value;Obtain the average value of the particle content of the preset particle size in second sample;Obtain the mineral aggregate pulverization amount therein, judge whether it exceeds threshold value, if within threshold value, it is qualified;The new detection method provided by the application fills the deficiency of the current standard for stone quality inspection index, can guide the accurate selection of aggregate before engineering implementation, and has high reliability.

Description

Technical Field

[0001] This application relates to the technical field of asphalt mixture construction, and in particular to a method and system for detecting aggregate pulverization in asphalt mixtures. Background Technology

[0002] In the field of highway construction, asphalt mixture pavement defects occur frequently; especially in early-stage damaged asphalt mixture pavements, the powder content is often much higher than the powder content during mix design testing, leading to an increased powder-to-binder ratio, loss of adhesion of the asphalt mixture, and resulting in loose and cracked asphalt mixture.

[0003] The current national and industry standards for testing aggregates used in asphalt pavement lack precise testing methods to determine whether aggregates will pulverize during use. Summary of the Invention

[0004] In order to obtain the trend of pulverization degree of grade asphalt mixture during the use of asphalt pavement, improve the accuracy of judging whether the aggregate in the asphalt mixture is pulverized, and prevent the asphalt pavement from being damaged early due to aggregate pulverization, this application provides a method and system for detecting aggregate pulverization in asphalt mixture.

[0005] The first aspect of this application provides a method for detecting aggregate pulverization in asphalt mixtures, which adopts the following technical solution:

[0006] A method for detecting aggregate pulverization in asphalt mixtures includes the following steps:

[0007] Prepare N portions of asphalt mixture aggregate samples according to the preset proportions;

[0008] Obtain the average particle content m0 ​​of the preset particle size in N samples of the asphalt mixture aggregate;

[0009] M Marshall specimens were prepared using the compaction method;

[0010] Obtained through heating device The first sample;

[0011] Remove separately From the asphalt in the first sample, obtain The second sample and The average mass m1 of the second sample; obtain The average particle content m2 of the preset particle size in the second sample;

[0012] Obtain the amount of aggregate pulverization (mf) in the asphalt mixture;

[0013] mf = m3 - m0;

[0014] m3 = (m1 - m2) / m1 × 100;

[0015] If mf≤1%, it is determined that the asphalt mixture configured by the preset ratio is qualified.

[0016] By adopting the technical scheme, a new detection method for aggregate pulverization in asphalt mixture is provided, which fills the deficiency of the current standard for stone quality inspection indexes, can control the selection of aggregate before the implementation of the project, prevent a large amount of rework waste caused by aggregate pulverization in asphalt mixture pavement, has a guiding role for improving the quality inspection of asphalt pavement materials, has high reliability, and is suitable for quality control of all grades of asphalt mixture roads.

[0017] Preferably, the method for obtaining the average value of the content of particles with a preset particle size in the asphalt mixture aggregate sample is specifically:

[0018] The content of particles less than 0.075 mm in each asphalt mixture aggregate sample is obtained by using a water washing method.

[0019] The average value m0 of the content of N particles is obtained.

[0020] By adopting the technical scheme, the content less than 0.075 mm is accurately researched to accurately control the selection of aggregate.

[0021] Preferably, the asphalt mixture aggregate sample includes first-type particle aggregate, second-type particle aggregate, third-type particle aggregate, fourth-type particle aggregate, fifth-type particle aggregate, sixth-type particle aggregate, and modified asphalt.

[0022] The particle size of the first-type particle aggregate is d1, and d1∈[16mm, 19mm).

[0023] The particle size of the second-type particle aggregate is d2, and d2∈[13.2mm, 16mm).

[0024] The particle size of the third-type particle aggregate is d3, and d3∈[9.5mm, 13.2mm).

[0025] The particle size of the fourth-type particle aggregate is d4, and d4∈[4.75mm, 9.5mm).

[0026] The particle size of the fifth-type particle aggregate is d5, and d5∈[2.36mm, 4.75mm).

[0027] The particle size of the sixth-type particle aggregate is d6, and d6∈[0.3mm, 2.36mm).

[0028] The softening point of the modified asphalt is T, and T∈[80℃, 85℃].

[0029] By adopting the technical scheme, the preparation accuracy of the aggregate sample of the asphalt mixture is improved.

[0030] Preferably, the content of the first type of aggregate with the particle size is 10%;

[0031] The content of the second type of aggregate with the particle size is 25%;

[0032] The content of the third type of aggregate with the particle size is 20%;

[0033] The content of the fourth type of aggregate with the particle size is 15%;

[0034] The content of the fifth type of aggregate with the particle size is 10%;

[0035] The content of the sixth type of aggregate with the particle size is 20%.

[0036] By adopting the technical scheme, a standard configuration ratio is provided, which provides a clear reference for subsequent research.

[0037] Preferably, the first type of aggregate with the particle size, the second type of aggregate with the particle size, the third type of aggregate with the particle size, the fourth type of aggregate with the particle size, the fifth type of aggregate with the particle size, and the sixth type of aggregate with the particle size are aggregates obtained after being baked at a temperature of 190℃±5℃ for 4 hours.

[0038] By adopting the technical scheme, the shear strength of the aggregate sample of the asphalt mixture is ensured, and the error is reduced.

[0039] Preferably, N≥3.

[0040] By adopting the technical scheme, the data reliability of the obtained aggregate sample of the asphalt mixture is ensured.

[0041] Preferably, M≥6, and M is an even number.

[0042] By adopting the technical scheme, the data reliability of the obtained second sample is ensured.

[0043] Preferably, the heating device is an oven.

[0044] The preset temperature of the heating device is 145℃±5℃.

[0045] By adopting the technical scheme, the heating of the Marshall test piece is sufficient, each two Marshall test pieces form a first sample, and the quality of each first sample obtained is uniform.

[0046] Preferably, the method for obtaining the average value of the content of the particles with the preset particle size in the second sample is specifically:

[0047] The content of the particles below 0.075mm in each second sample is obtained by using a water washing method.

[0048] Get The average value of each particle content, m2.

[0049] By adopting the above technical solution, precise research can be conducted on the content below 0.075mm, thereby improving the data reliability of the second sample.

[0050] The second aspect of this application provides a detection system for aggregate pulverization in asphalt mixtures, including...

[0051] The sample preparation unit is configured to prepare N portions of asphalt mixture aggregate samples based on a preset ratio.

[0052] The Marshall specimen preparation unit is configured to prepare M Marshall specimens using the compaction method;

[0053] The heating unit is configured to heat M Marshall specimens using a heating device to obtain... The first sample;

[0054] The purification unit is configured to remove asphalt from each of the first samples and obtain... A second sample;

[0055] The weighing unit is configured to obtain the average particle content m0 ​​of a preset particle size in N asphalt mixture aggregate samples, and to obtain... The average mass m1 of the second sample and the acquisition The average particle content m2 of the preset particle size in each second sample;

[0056] The judgment unit is configured to determine whether the amount of aggregate pulverization mf in the asphalt mixture meets the standard threshold mb.

[0057] If mf≤mb, then it is considered qualified;

[0058] Where mf = m3 - m0;

[0059] m3 = (m1 - m2) / m1 × 100.

[0060] By adopting the above technical solution, an innovative detection system for aggregate pulverization is proposed, providing a standard for the selection of asphalt mixture materials, preventing early damage to the pavement caused by aggregate pulverization after construction, effectively reducing rework and improving construction quality.

[0061] In summary, this application includes at least one of the following beneficial technical effects:

[0062] 1. This application proposes an innovative method for testing aggregate pulverization in asphalt mixtures, filling the gaps in current standards and playing a significant role in preventing early damage to asphalt pavements caused by aggregate pulverization.

[0063] 2. The method provided in this application can provide reliable guidance for the selection of aggregates in asphalt mixtures, avoid aggregate pulverization after later construction, effectively reduce pavement damage, and improve pavement service life.

[0064] 3. This invention provides standard values ​​for testing the pulverization of aggregates in asphalt mixture pavements, filling the gaps in the current standards for selecting aggregate quality and providing guidance for improving the quality inspection of road aggregates. Attached Figure Description

[0065] Figure 1 This is a schematic diagram of the steps in the detection method for aggregate pulverization in asphalt mixtures in this application. Detailed Implementation

[0066] This application discloses a method and system for detecting aggregate pulverization in asphalt mixtures.

[0067] The following is in conjunction with the appendix Figure 1 This application will be described in further detail.

[0068] Reference Figure 1 The first aspect of this application discloses a method for detecting aggregate pulverization in asphalt mixtures, comprising the following steps:

[0069] Step S100: Prepare N portions of asphalt mixture aggregate samples according to the preset ratio. In this embodiment, N≥3, that is, at least 3 portions of asphalt mixture aggregate samples are prepared, and the mass of each asphalt mixture aggregate sample is not less than 3000g, accurate to 1g.

[0070] Obtain the average particle content m0 ​​of the preset particle size in N asphalt mixture aggregate samples, accurate to 0.01%; specifically, use the water washing method to obtain the particle content below 0.075mm in each asphalt mixture aggregate sample, and obtain the average particle content m0 ​​of N samples, accurate to 0.01%.

[0071] Step S200: Prepare M Marshall specimens using the compaction method; obtain the desired results using a heating device. The first sample is prepared by double-sided 75-degree hammering to form a standard Marshall specimen, with a minimum of 6 specimens (M≥6). The prepared specimens are placed in a heating device, with two Marshall specimens combined to form one sample. The sample is heated at 145℃±5℃ until it reaches a dispersed state and constant weight. The two specimens are then mixed together to form a complete sample. One sample.

[0072] Step S300, using a combustion furnace method to... The first sample was heated to remove the asphalt, and the asphalt was removed to obtain... A second sample was obtained after cooling. The average mass m1 of the second sample.

[0073] Step S400, obtain The average particle content m2 of the preset particle size in each second sample; specifically, the content of particles smaller than 0.075 mm in each second sample is obtained by water washing, and then the content is obtained. The average value of the particle content, m2, accurate to 0.01%.

[0074] Step S500: Obtain the amount of aggregate pulverization mf in the asphalt mixture;

[0075] mf = m3 - m0;

[0076] m3 = (m1 - m2) / m1 × 100;

[0077] If mf≤1%, the asphalt mixture configured according to the preset proportion is deemed qualified, that is, the aggregate is deemed to meet the performance of asphalt mixture and can be used as a standard for production. This ensures that the asphalt mixture after construction will not pulverize and that its actual service life is not less than the expected service life.

[0078] If mf>1%, the aggregate used in the preset mix design is deemed unqualified and cannot be used for asphalt mixture production and construction.

[0079] In this embodiment, the asphalt mixture aggregate sample includes aggregates of the first, second, third, fourth, fifth, and sixth particle sizes, as well as modified asphalt; wherein, the aggregates of the first, second, third, fourth, fifth, and sixth particle sizes are aggregates obtained after being dried at 190℃±5℃ for 4 hours.

[0080] Specifically, the particle size of the first type of aggregate is d1, where d1 ∈ [16 mm, 19 mm); the dosage of the first type of aggregate is 10%.

[0081] The particle size of the second type of aggregate is d2, where d2 ∈ [13.2 mm, 16 mm); the content of the second type of aggregate is 25%.

[0082] The particle size of the third type of aggregate is d3, where d3 ∈ [9.5 mm, 13.2 mm); the content of the third type of aggregate is 20%.

[0083] The particle size of the fourth type of aggregate is d4, where d4 ∈ [4.75 mm, 9.5 mm); the dosage of the fourth type of aggregate is 15%.

[0084] The fifth type of particle size aggregate has a particle size of d5, d5∈[2.36mm, 4.75mm); the content of the fifth type of particle size aggregate is 10%.

[0085] The sixth type of particle size aggregate has a particle size of d6, d6∈[0.3mm, 2.36mm); the content of the sixth type of particle size aggregate is 20%.

[0086] The softening point of the modified asphalt is T, T∈[80℃, 85℃], and the modified asphalt is used by the method of external addition.

[0087] Preferably, M is an even number.

[0088] In the embodiment, the heating device is an oven, and accurate temperature control can be performed.

[0089] The implementation principle of the detection method for aggregate pulverization in the asphalt mixture in the embodiment is that a new detection method is proposed. In the initial stage of selecting the asphalt mixture, a sample is prepared by the aggregate in a specified proportion, the content of the aggregate less than 0.075 mm is measured through the heating and stress action of the asphalt mixture, and the percentage content of the aggregate pulverization after the heating and stress action is calculated, thereby providing a reference standard suitable for the control of the aggregate pulverization amount of the asphalt mixture pavement.

[0090] Many methods and standards for the processing and production control of the asphalt mixture are formulated in the current foreign, domestic and industry standards, and the index of the detection of the aggregate and the asphalt mixture is specified as follows: the detection index of the aggregate before use is divided into coarse aggregate and fine aggregate. Specifically, the detection index of the coarse aggregate includes stone crushing value and high-temperature crushing value, Los Angeles abrasion loss, apparent relative density, water absorption, firmness, needle content, content less than 0.075 mm and soft stone content; the detection index of the fine aggregate includes apparent relative density, firmness, content less than 0.075 mm, sand equivalent, skid resistance, methylene blue value.

[0091] The detection of the asphalt mixture before construction mainly includes six aspects of the high-temperature stability, low-temperature crack resistance, water stability, durability, skid resistance and production quality control; the corresponding detection items are as follows: (1) high-temperature stability: Marshall stability, flow value, dynamic stability; (2) low-temperature crack resistance: average linear shrinkage coefficient, splitting tensile strength; (3) water stability: adhesion of asphalt and aggregate, residual stability, freeze-thaw; (4) durability: saturation, asphalt content; (5) skid resistance: aggregate polishing value; (6) production quality control: mixture gradation, asphalt content, temperature.

[0092] The test items after the construction of asphalt mixture mainly include: compaction degree, thickness, water resistance, skid resistance (with structure depth and friction coefficient), flatness, deflection, centerline deviation, longitudinal elevation, width and cross slope.

[0093] Since the 1980s and 1990s, with the expansion of the application of asphalt mixture pavement, asphalt mixture pavement has many problems while having many advantages, which has attracted the attention and research of many experts, and various methods such as asphalt modification, improving aggregate control standards, adding fibers, adding additives, and changing mixture gradation have been proposed, and many new pavement structures have also appeared. However, many diseases of asphalt mixture pavement have not been solved.

[0094] Among them, early pavement diseases caused by stone materials occur from time to time. It is found that the inspection indicators of aggregate and asphalt mixture are not comprehensive, various verification methods are constantly improved, and the evaluation standards mentioned above are formed, and the bonding performance of asphalt and aggregate is proposed as the index requirement for judgment. Limestone has become the main material of asphalt mixture pavement because of its best alkaline aggregate effect, but its wear resistance is generally poor, which will reduce the skid resistance of the pavement after a period of use, so it has become the first choice for the middle and lower layers. The bonding performance of basalt and asphalt is slightly lower than that of limestone, but it has good wear resistance, so basalt is often used as the design concept for the upper layer in asphalt pavement construction.

[0095] In the more than ten years of implementation, asphalt mixture pavement diseases caused by stone materials occur from time to time, and the cost of disease treatment rises from several million to several hundred million, and from several hundred million to several billion, and the treatment cost is getting higher and higher. Due to the traffic volume and the effect of large heavy vehicles, the early diseases of asphalt mixture pavement occur earlier and earlier. Ten years ago, most of the early diseases of asphalt mixture occurred after 1 to 2 years of opening to traffic, and in recent years, some expressways have been found to have early diseases within 1 year or a few months of opening to traffic, which is far from the design requirements of more than ten years of use, which has attracted attention.

[0096] For many years, some local management departments have made regulations prohibiting the use of certain types of stone materials in asphalt mixture pavement, and test and technical personnel have adopted the method of directly denying such stone materials. As long as the stone materials used in the pavement have diseases, they will not be used in the future.

[0097] Among the commonly used rock types, igneous rocks (basalt) have a compressive strength between 10 MPa and 190 MPa; metamorphic rocks (quartzite, granite) have a compressive strength between 10 MPa and 160 MPa; clastic rocks (sandstone, conglomerate) of poor quality have a compressive strength of less than 10 MPa, while good quality ones can reach over 160 MPa; carbonate rocks (limestone, shale, dolomite) of poor quality have a compressive strength of only about 10 MPa, while good quality ones can reach over 120 MPa. Therefore, due to the different strengths of the same type of stone... Significant differences in strength and wear resistance lead to wasted manpower and resources during material preparation. Furthermore, during production, it was discovered that asphalt mixtures made from similar aggregates, while meeting industry-standard quality requirements, still exhibited quality problems after construction. Specifically, while the aggregates met the current standards, they still showed signs of pulverization, resulting in an abnormally high content of particles smaller than 0.075mm in the asphalt mixture. This caused defects such as loss of adhesion, loosening, and cracking in the asphalt mixture, and these potential defects were already present before the asphalt pavement construction was completed.

[0098] The scheme disclosed in this application provides an aggregate selection method that can play a control role in the early preparation of materials, greatly reduce the manpower and material costs invested in the early preparation of materials, ensure construction quality, prevent the occurrence of diseases caused by aggregate pulverization in asphalt mixture pavement, and can be used as a reference for controlling the amount of pulverization.

[0099] The second aspect of this application discloses a detection system for aggregate pulverization in asphalt mixtures, comprising:

[0100] The sample preparation unit is configured to prepare N portions of asphalt mixture aggregate samples based on a preset ratio.

[0101] The Marshall specimen preparation unit is configured to prepare M Marshall specimens using the compaction method;

[0102] The heating unit is configured to heat M Marshall specimens using a heating device to obtain... The first sample;

[0103] The purification unit is configured to remove asphalt from each of the first samples and obtain... A second sample;

[0104] The weighing unit is configured to obtain the average particle content m0 ​​of a preset particle size in N asphalt mixture aggregate samples, and to obtain... The average mass m1 of the second sample and the acquisition The average particle content m2 of the preset particle size in each second sample;

[0105] The judgment unit is configured to determine whether the amount of aggregate pulverization mf in the asphalt mixture meets the standard threshold mb.

[0106] If mf≤mb, it is determined as qualified;

[0107] Wherein, mf=m3-m0;

[0108] m3=(m1-m2) / m1*100.

[0109] The second aspect of the application innovatively provides a detection system for mineral material pulverization, effectively prevents the damage of asphalt mixture pavement caused by the use of excessive pulverized aggregate in engineering, and ensures the engineering quality, that is, provides a new standard for the selection of asphalt mixture materials.

[0110] The above are preferred embodiments of the application, and do not limit the protection scope of the application, so: any equivalent changes made according to the structure, shape, principle of the application should be covered within the protection scope of the application.

Claims

1. A method for detecting aggregate pulverization in asphalt mixtures, characterized in that: Includes the following steps: Prepare N portions of asphalt mixture aggregate samples according to the preset proportions; N≥3; Obtain the average particle content m0 ​​of the preset particle size in N samples of the asphalt mixture aggregate; The method for obtaining the average particle content of the preset particle size in the asphalt mixture aggregate sample is as follows: the content of particles smaller than 0.075 mm in each asphalt mixture aggregate sample is obtained by water washing; the average particle content m0 ​​of N samples is obtained. M Marshall specimens were prepared using the compaction method; M ≥ 6, and M is an even number. Obtained through heating device One first specimen, that is, every two Marshall specimens constitute one first specimen; Remove separately From the asphalt in the first sample, obtain The second sample and The average mass m1 of the second sample; Get The average particle content m2 of the preset particle size in the second sample; The method for obtaining the average content of particles with a preset particle size in the second sample is as follows: The content of particles smaller than 0.075 mm in each sample of the second sample is obtained using a water washing method; The average content of each particle, m2; Obtain the amount of aggregate pulverization (mf) in the asphalt mixture; mf = m3-m0; m3 = (m1 - m2) / m1 × 100; If mf≤1%, the asphalt mixture prepared according to the preset mix proportion is deemed qualified.

2. The method for detecting aggregate pulverization in asphalt mixtures according to claim 1, characterized in that: The asphalt mixture aggregate samples include aggregates of the first, second, third, fourth, fifth, and sixth particle sizes, as well as modified asphalt. The particle size of the first type of aggregate is d1, d1 [16mm, 19mm] The particle size of the first type of aggregate is d2, d2 [13.2mm, 16mm]; The particle size of the first type of aggregate is d3, d3 [9.5mm, 13.2mm]; The particle size of the first type of aggregate is d4, d4 [4.75mm, 9.5mm]; The particle size of the first type of aggregate is d5, d5 [2.36mm, 4.75mm]; The particle size of the first type of aggregate is d6, d6 [0.3mm, 2.36mm]; The softening point of the modified asphalt is T, T [80℃, 85℃].

3. The method for detecting aggregate pulverization in asphalt mixtures according to claim 2, characterized in that: The dosage of the first type of aggregate is 10%; The dosage of the second type of aggregate is 25%; The dosage of the third type of aggregate is 20%; The dosage of the fourth type of aggregate is 15%; The fifth type of aggregate is added at a rate of 10%. The amount of the sixth type of aggregate is 20%.

4. The method for detecting aggregate pulverization in asphalt mixtures according to claim 2, characterized in that: The first type of aggregate, the second type of aggregate, the third type of aggregate, the fourth type of aggregate, the fifth type of aggregate, and the sixth type of aggregate are aggregates obtained after being dried at 190ºC±5ºC for 4 hours.

5. The method for detecting aggregate pulverization in asphalt mixtures according to claim 1, characterized in that: The heating device is an oven; The preset temperature of the heating device is 145ºC±5ºC.

6. A detection system for aggregate pulverization in asphalt mixtures, used to perform the detection method for aggregate pulverization in asphalt mixtures as described in any one of claims 1-5, characterized in that: include The sample preparation unit is configured to prepare N portions of asphalt mixture aggregate samples based on a preset ratio. The Marshall specimen preparation unit is configured to prepare M Marshall specimens using the compaction method; The heating unit is configured to heat M Marshall specimens using a heating device to obtain... The first sample; The purification unit is configured to remove asphalt from each of the first samples and obtain... A second sample; The weighing unit is configured to obtain the average particle content m0 ​​of a preset particle size in N asphalt mixture aggregate samples, and to obtain... The average mass m1 of the second sample and the acquisition The average particle content m2 of the preset particle size in each second sample; The judgment unit is configured to determine whether the amount of aggregate pulverization mf in the asphalt mixture meets the standard threshold mb. If mf≤mb, then it is considered qualified; Where mf = m3-m0; m3 = (m1 - m2) / m1 × 100.

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