Method for determining classification standard of wear-resistant and skid-resistant aggregate based on mmls accelerated loading test

Abstract

This application discloses a method for determining the classification criteria of wear-resistant and skid-resistant aggregates based on the MMLS accelerated loading test. The method includes: obtaining various physical and mechanical properties of the aggregate; obtaining multiple friction pendulum measurements on rutted slab specimens formed from the aggregate under accelerated loading conditions applied by an MMLS accelerated loading testing machine; establishing linear fitting relationships between the friction pendulum values ​​and each physical and mechanical property; based on the linear fitting relationships, estimating the physical and mechanical property values ​​from preset key friction pendulum values; and combining the key friction pendulum values ​​and the estimated physical and mechanical property values ​​to form a classification standard. This scheme provides a reference for the design of skid-resistant asphalt pavements, considers the influence of aggregates in existing skid-resistant pavement designs, and provides a more scientific design method for the design of skid-resistant and durable asphalt pavements, enabling asphalt pavements to have excellent skid resistance while maintaining other properties unchanged.

Description

Technical Field

[0001] This application relates to the technical field of anti-skid aggregates for asphalt pavement, and in particular to a method for determining the classification criteria of wear-resistant and anti-skid aggregates based on the MMLS accelerated loading test. Background Technology

[0002] Good skid resistance is a crucial prerequisite for ensuring driving safety. In recent years, frequent traffic accidents in highway tunnels in my country have resulted in a persistently high accident rate, causing significant loss of life and property. The root cause is not difficult to find, but it is closely related to the insufficient skid resistance of tunnel pavements. The skid resistance of asphalt pavements is closely related to the type of aggregate selected. Asphalt pavements constructed with different aggregates exhibit varying degrees of skid resistance and durability. Therefore, selecting aggregates with excellent skid resistance is of paramount importance.

[0003] In related technologies, the evaluation index for the skid resistance of aggregates is singular, namely the polished surface value (PSV). This single technical indicator cannot guarantee the skid resistance and durability of the selected aggregates, nor can it reflect the long-term skid resistance of asphalt pavements. Furthermore, the standard setting does not consider the requirements for the skid resistance of asphalt pavements under special environmental conditions such as tunnels. Therefore, it is of great significance to select aggregates with excellent skid resistance from multiple perspectives based on the long-term skid resistance of asphalt pavements and their own physical and mechanical properties. Summary of the Invention

[0004] In view of this, this application provides a method for determining the classification standard of wear-resistant and anti-skid aggregates based on the MMLS accelerated loading test, which can more comprehensively classify the anti-skid performance of aggregates.

[0005] This application provides a method for determining the classification criteria of wear-resistant and anti-skid aggregates based on the MMLS accelerated loading test, including:

[0006] Obtain the physical and mechanical properties of the aggregates separately;

[0007] For the rut plate specimen formed from the aggregate, multiple friction pendulum measurements were obtained under accelerated loading conditions applied by the MMLS accelerated loading test machine.

[0008] Based on multiple measurements of the friction pendulum, linear fitting relationships between the friction pendulum values ​​and various physical and mechanical indicators were established.

[0009] Based on the linear fitting relationship, the corresponding physical and mechanical index values ​​are derived from the key friction pendulum values ​​used in the preset level classification.

[0010] The key friction pendulum values ​​and the calculated values ​​of physical and mechanical indicators are combined to form a classification standard.

[0011] Optionally, the physical and mechanical properties are one or more of the following: polishing value PSV, Los Angeles wear value Qa, weighted Mohs hardness Hm, Vickers hardness Hw, hard mineral content, Al2O3, and total mass ratio of SiO2.

[0012] Optionally, the dimensions of the rut plate specimen are 300cm×300cm×30cm.

[0013] Optionally, the key friction pendulum value is 35, 42, or 47 BPN.

[0014] Optionally, the aggregate is one or more of the following: feldspathic sandstone, quartz sandstone, red sandstone, limestone, basalt, amphibolite, diabase, gabbro, and granite.

[0015] The above-described method for determining the classification criteria of wear-resistant and skid-resistant aggregates based on the MMLS accelerated loading test can provide a reference for the design of skid-resistant asphalt pavements. It allows for the consideration of the influence of aggregates in the existing design of skid-resistant pavements, providing a more scientific design method for the design of skid-resistant and durable asphalt pavements, and enabling asphalt pavements to have excellent skid resistance while keeping other properties unchanged. Attached Figure Description

[0016] The technical solution and other beneficial effects of this application will become apparent from the following detailed description of specific embodiments in conjunction with the accompanying drawings.

[0017] Figure 1 The graph shows the linear fit between the stabilized anti-skid performance and the aggregate PSV.

[0018] Figure 2 The graph shows the linear fit between the stabilized anti-skid performance and the aggregate Qa.

[0019] Figure 3 The graph shows the linear fit between the stabilized anti-skid performance and the aggregate Hw.

[0020] Figure 4 The graph shows the linear fit between the stabilized anti-skid performance and the aggregate Hm.

[0021] Figure 5 The graph shows the linear fit between the stabilized anti-skid performance and the content of hard minerals in the aggregate.

[0022] Figure 6 The graph shows the linear fitting relationship between the stabilized anti-skid performance and the total mass ratio of Al2O3+SiO2 in the aggregate. Detailed Implementation

[0023] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0024] In the description of this application, it should be understood that the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, features defined as "first" or "second" may explicitly or implicitly include one or more of the stated features. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0025] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between them; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication between two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0026] The following disclosure provides many different embodiments or examples for implementing different structures of this application. To simplify the disclosure, specific examples of components and arrangements are described below. Of course, these are merely examples and are not intended to limit the scope of this application. Furthermore, reference numerals and / or letters may be repeated in different examples; such repetition is for simplification and clarity and does not in itself indicate a relationship between the various embodiments and / or arrangements discussed. In addition, various specific examples of processes and materials are provided in this application, but those skilled in the art will recognize the application of other processes and / or the use of other materials.

[0027] The method for determining the classification criteria of wear-resistant and anti-skid aggregates based on the MMLS accelerated loading test in this application includes the following steps:

[0028] S1. Obtain the various physical and mechanical properties of the aggregate. Here, the physical and mechanical properties include the aggregate's polishing value PSV, Los Angeles abrasion value Qa, weighted Mohs hardness Hm, Vickers hardness Hw, hard mineral content, and the total mass ratio of Al2O3+SiO2.

[0029] S2. For the rut plate specimen formed from the aggregate, multiple friction pendulum (BPN) measurements are obtained under accelerated loading conditions applied by the MMLS accelerated loading test machine.

[0030] Here, after each application of accelerated loading, a pendulum friction meter is used to measure the friction pendulum value. When the friction pendulum value tends to stabilize, the loading is stopped, and the final pendulum value is recorded.

[0031] S3. Based on multiple measurements of the friction pendulum, establish linear fitting relationships between the friction pendulum values ​​and various physical and mechanical properties. Please refer to [reference needed]. Figures 1-6 .

[0032] S4. Based on the linear fitting relationship, the corresponding physical and mechanical index values ​​are derived from the key friction pendulum values ​​used in the preset grade classification.

[0033] The preset grade classification can be based on the 1997 edition of my country's "Specifications for Design of Asphalt Pavement on Highways" (JTJ-014-97). In this preset grade classification, the traffic accident rate is high when the pavement's anti-skid performance degrades to BPN < 35; fewer traffic accidents occur in rainy weather when BPN > 42; and the pavement's anti-skid performance is excellent when BPN > 47. Therefore, the critical friction pendulum values ​​are 35, 42, and 47.

[0034] S5. Combine the key friction pendulum values ​​and the calculated values ​​of physical and mechanical indicators into a grade classification standard.

[0035] Example 1

[0036] A Method for Determining Classification Criteria of Wear-Resistant and Anti-Slip Aggregates Based on MMLS Accelerated Loading Test

[0037] Nine different types of aggregates were selected, including feldspathic sandstone, quartz sandstone, red sandstone, limestone, basalt, amphibolite, diabase, gabbro, and granite.

[0038] Accelerated polishing mills were used to accelerate the polishing of aggregates with particle sizes ranging from 9.5 to 13.2 mm, and the polishing value (PSV) of each aggregate was measured.

[0039] Table 1. Polishing Value (PSV) Test Results of Aggregates

[0040]

[0041] Abrasion tests were conducted on mixed aggregates with particle sizes of 4.75–9.5 mm and 9.5–16 mm, each weighing 2500 g, using a Los Angeles abrasion tester to determine the abrasion value Qa of each aggregate.

[0042] Table 2. Test results of abrasion value Qa of aggregates.

[0043]

[0044] XRD diffraction analysis was used to determine the mineral types and proportions in each aggregate. Then, based on the hardness and proportion of the minerals, the weighted Mohs hardness of the aggregates was calculated using a weighted formula.

[0045]

[0046] Hm—Weighted Mohs hardness; H i —Mohs hardness of each mineral; α i —The percentage of each mineral component in the aggregate.

[0047] Table 3 Calculation results of Mohs hardness Hm of aggregates

[0048]

[0049] The Vickers hardness (Hw) of different aggregates was tested using a micro Vickers hardness tester.

[0050] Table 4. Vickers hardness (Hw) test results of aggregates.

[0051]

[0052] XRD diffraction analysis was used to determine the type and proportion of each mineral in each aggregate. The sum of the proportions of hard minerals with a Mohs hardness greater than or equal to 6 was used to determine the content of hard minerals.

[0053] Table 5 Results of hard mineral content in aggregates

[0054]

[0055] XRF analysis was used to determine the total mass ratio of Al2O3+SiO2 in each aggregate.

[0056] Table 6 Results of the total mass ratio of Al2O3+SiO2 in the aggregates

[0057]

[0058] Aggregates and asphalt were mixed together and molded into rutted slab specimens. These specimens were then cut and placed in the MMLS accelerated loading test equipment for accelerated loading tests. (See...) Figure 1 .

[0059] After each test, the pendulum value was measured using a pendulum friction meter, see [link / reference]. Figure 2 Once the pendulum value stabilizes, loading stops, and the final pendulum value is recorded.

[0060] Table 6. Stable post-swing value BPN

[0061]

[0062] Linear fitting is performed between the pendulum value and various physical and mechanical properties, such as... Figure 3 .

[0063] When BPN is 35, 42, and 47 respectively, the corresponding values ​​of each index can be derived by reverse calculation, and the different grade standards of wear-resistant and anti-skid aggregates can be determined.

[0064] Table 7. Recommended aggregate classification indicators and standards based on pavement skid resistance and durability.

[0065]

[0066]

[0067] The above description is merely a preferred embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application.

Claims

1. A method for determining the classification criteria of wear-resistant and anti-skid aggregates based on MMLS accelerated loading test, characterized in that, include: The physical and mechanical properties of the aggregate are obtained separately; the physical and mechanical properties are one or more of the following: polishing value PSV, Los Angeles abrasion value Qa, weighted Mohs hardness Hm, Vickers hardness Hw, hard mineral content, and total mass ratio of Al2O3+SiO2. For the rut plate specimen formed from the aggregate, multiple friction pendulum measurements were obtained under accelerated loading conditions applied by the MMLS accelerated loading test machine. Based on multiple measurements of the friction pendulum, linear fitting relationships between the friction pendulum values ​​and various physical and mechanical indicators were established. Based on the linear fitting relationship, the corresponding physical and mechanical index values ​​are derived from the key friction pendulum values ​​used in the preset level classification; the key friction pendulum values ​​are BPN values ​​of 35, 42, and 47. The key friction pendulum values ​​and the calculated values ​​of physical and mechanical indicators are combined to form a classification standard.

2. The method for determining the classification criteria of wear-resistant and anti-skid aggregates based on MMLS accelerated loading test according to claim 1, characterized in that, The dimensions of the rut plate specimen are 300cm×300cm×30cm.

3. The method for determining the classification criteria of wear-resistant and anti-skid aggregates based on MMLS accelerated loading test according to claim 1, characterized in that, The aggregate is one or more of the following: feldspathic sandstone, quartz sandstone, red sandstone, limestone, basalt, amphibolite, diabase, gabbro, and granite.

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