A method and system for testing the coarse aggregate content in asphalt mixtures

Abstract

This invention discloses a method and system for testing the aggregate content of coarse aggregates in asphalt mixtures, relating to the field of road engineering. The method includes: obtaining the apparent density and mass of each stone in multiple coarse aggregate samples; calculating the average apparent density and total mass of each coarse aggregate sample based on the apparent density and mass of each stone; determining the aggregate mass of each coarse aggregate sample based on the average apparent density and the apparent density and mass of each stone; and calculating the aggregate content of the coarse aggregate in the asphalt mixture based on the aggregate mass of each coarse aggregate sample and the corresponding total mass of each coarse aggregate sample. This invention can effectively test the aggregate content of different coarse aggregates.

Description

Technical Field

[0001] This invention relates to the field of road engineering, and in particular to a method and system for testing the coarse aggregate content in asphalt mixtures. Background Technology

[0002] Coarse aggregate is a crucial component of asphalt mixtures, and its uniformity and stability significantly impact the compaction degree, maximum theoretical density, and porosity of the asphalt mixture. Therefore, coarse aggregate should be relatively uniform, and the content of miscellaneous stones should be controlled within a reasonable range to ensure the accuracy of tests and the construction quality of asphalt pavements. However, currently, technicians still rely on visual observation, primarily based on color and experience, to assess the uniformity and stability of coarse aggregate. This method has two major drawbacks: first, the color of coarse aggregate cannot effectively distinguish its uniformity; second, the method is heavily influenced by human factors, leading to significant deviations in the results.

[0003] Engineering practice has proven that the density of coarse aggregate in asphalt mixtures is one of the key indicators for judging the uniformity of coarse aggregates. Currently used mix design methods, such as the Marshall method and the Superpave method, all consider the volumetric properties of asphalt mixtures as an important indicator. Therefore, if the uniformity and stability of the coarse aggregates are poor, and if the coarse aggregates contain a large amount of mixed stones, the density of the coarse aggregates is prone to large fluctuations. This will prevent the designed mix proportions from effectively guiding actual construction. Furthermore, if the density of the coarse aggregates fluctuates significantly, the compaction index controlled by test sections during asphalt pavement quality testing will be ineffective, making it difficult to control the compaction degree of the asphalt pavement.

[0004] Industry professionals are aware of the issue of coarse aggregate content; however, due to the lack of suitable testing methods, the quality of coarse aggregate is difficult to control effectively. Some quarries meet the requirements using conventional testing methods, but their aggregate has poor uniformity and high content of miscellaneous stones. The density of coarse aggregate used in the design differs from that used in actual construction by more than 0.1, seriously affecting construction quality. Some highways have passed various tests for compaction indicators and have a void ratio controlled below 6%, but large-scale potholes appeared shortly after they were opened to traffic. Subsequent analysis revealed that the coarse aggregate density deviation was large, the compaction control indicators were "distorted," and the actual void ratio of the asphalt pavement was more than 8%. Summary of the Invention

[0005] The purpose of this invention is to provide a method and system for testing the content of coarse aggregate in asphalt mixtures, which can effectively test the content of different coarse aggregates.

[0006] To achieve the above objectives, the present invention provides the following solution:

[0007] A method for testing the coarse aggregate content in asphalt mixtures, the method comprising:

[0008] Obtain the apparent density and mass of each stone in multiple coarse aggregate samples;

[0009] Based on the apparent density and mass of each stone, calculate the average apparent density and total mass of each coarse aggregate sample;

[0010] The mass of the mixed stones in each coarse aggregate sample is determined based on the average apparent density of each coarse aggregate sample and the apparent density and mass of each stone.

[0011] The content of coarse aggregate in the asphalt mixture is calculated based on the mass of the aggregate in each coarse aggregate sample and the total mass of the corresponding coarse aggregate sample.

[0012] Optionally, each coarse aggregate sample meets the minimum sampling weight requirement: 0.1 kg for coarse aggregate with a size of 5 mm to 10 mm; 0.5 kg for coarse aggregate with a size of 10 mm to 20 mm; and 1 kg for coarse aggregate with a size of 10 mm to 25 mm.

[0013] Optionally, determining the mass of the aggregate in each coarse aggregate sample based on the average apparent density of each sample and the apparent density and mass of each individual stone includes:

[0014] Based on the average apparent density of each coarse aggregate sample and the apparent density of each stone, the type of each stone in each coarse aggregate sample is determined; the type includes mixed stones and non-mixed stones.

[0015] The mass of miscellaneous stones in each coarse aggregate sample is determined based on the mass of each stone.

[0016] Optionally, the step of calculating the coarse aggregate content in the asphalt mixture based on the mass of the aggregate in each coarse aggregate sample and the total mass of each coarse aggregate sample specifically includes:

[0017] The content of miscellaneous stone in each coarse aggregate sample is calculated based on the mass of miscellaneous stone in each sample and the total mass of each sample.

[0018] Based on the aggregate content of each coarse aggregate sample, the average aggregate content of multiple coarse aggregate samples is calculated to obtain the aggregate content of coarse aggregate in the asphalt mixture.

[0019] A system for testing the coarse aggregate content in asphalt mixtures, applied to the aforementioned method for testing the coarse aggregate content in asphalt mixtures, the system comprising:

[0020] The acquisition module is used to acquire the apparent density and mass of each stone in multiple coarse aggregate samples;

[0021] The calculation module is used to calculate the average apparent density and total mass of each coarse aggregate sample based on the apparent density and mass of each stone.

[0022] The mixed stone quality determination module is used to determine the mixed stone quality of each coarse aggregate sample based on the average apparent density of each sample and the apparent density and quality of each stone.

[0023] The mixed stone content determination module is used to calculate the mixed stone content of coarse aggregate in asphalt mixture based on the mass of mixed stone in each sample of coarse aggregate and the total mass of each sample of coarse aggregate.

[0024] An electronic device includes a memory and a processor, the memory storing a computer program, and the processor running the computer program to enable the electronic device to perform the above-described method for testing the coarse aggregate content in asphalt mixtures.

[0025] A computer-readable storage medium storing a computer program that, when executed by a processor, implements the above-described method for testing the coarse aggregate content in asphalt mixtures.

[0026] According to specific embodiments provided by the present invention, the present invention discloses the following technical effects:

[0027] This invention provides a method for testing the aggregate content of coarse aggregate in asphalt mixtures, comprising: obtaining the apparent density and mass of each aggregate in multiple coarse aggregate samples; calculating the average apparent density and total mass of each coarse aggregate sample based on the apparent density and mass of each aggregate; determining the aggregate mass of each coarse aggregate sample based on the average apparent density and the apparent density and mass of each aggregate; and calculating the aggregate content of coarse aggregate in the asphalt mixture based on the aggregate mass of each coarse aggregate sample and the corresponding total mass of each coarse aggregate sample. Compared with the commonly used method of visual observation and subjective judgment of aggregate content, this method is simple and easy to operate, can effectively test the aggregate content of different coarse aggregates, and can effectively ensure the accuracy of related tests on asphalt mixtures. Attached Figure Description

[0028] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0029] Figure 1 Flowchart of the method for testing the coarse aggregate content in asphalt mixtures provided by the present invention;

[0030] Figure 2 A flowchart illustrating the specific implementation of the coarse aggregate stone content testing method provided in this embodiment of the invention;

[0031] Figure 3 A block diagram of the coarse aggregate content testing system for asphalt mixtures provided by the present invention.

[0032] Symbol explanation:

[0033] Acquisition Module 1, Calculation Module 2, Determination Module for Quality of Miscellaneous Stones Module 3, Determination Module for Content of Miscellaneous Stones Module 4. Detailed Implementation

[0034] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0035] The purpose of this invention is to provide a method and system for testing the content of coarse aggregate in asphalt mixtures, which can effectively test the content of different coarse aggregates.

[0036] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0037] Example 1

[0038] like Figure 1 As shown, the present invention provides a method for testing the coarse aggregate content in asphalt mixtures, the method comprising:

[0039] Step S1: Obtain the apparent density and mass of each stone in multiple coarse aggregate samples.

[0040] Specifically, each coarse aggregate sample meets the minimum sampling weight requirement: the minimum sampling weight for coarse aggregate with a size of 5mm to 10mm is 0.1kg; the minimum sampling weight for coarse aggregate with a size of 10mm to 20mm is 0.5kg; and the minimum sampling weight for coarse aggregate with a size of 10mm to 25mm is 1kg.

[0041] Step S2: Based on the apparent density and mass of each stone, calculate the average apparent density and total mass of each coarse aggregate sample.

[0042] Step S3: Determine the mass of the mixed stones in each coarse aggregate sample based on the average apparent density of each coarse aggregate sample and the apparent density and mass of each stone.

[0043] S3 specifically includes:

[0044] Step S31: Determine the type of each stone in each coarse aggregate sample based on the average apparent density of each coarse aggregate sample and the apparent density of each stone; the type includes mixed stones and non-mixed stones.

[0045] Step S32: Determine the mass of miscellaneous stones in each coarse aggregate sample based on the mass of each stone.

[0046] Step S4: Calculate the aggregate content of coarse aggregate in asphalt mixture based on the aggregate mass of each coarse aggregate sample and the total mass of each coarse aggregate sample.

[0047] S4 specifically includes:

[0048] Step S41: Calculate the aggregate content of each coarse aggregate sample based on the aggregate mass of each sample and the total mass of each sample.

[0049] Step S42: Based on the aggregate content of each coarse aggregate sample, calculate the average aggregate content of multiple coarse aggregate samples to obtain the aggregate content of coarse aggregate in the asphalt mixture.

[0050] Figure 2 This is a flowchart illustrating the specific implementation of the coarse aggregate stone content testing method provided in this embodiment of the invention; for example... Figure 2 As shown, the practical application process of the method for testing the coarse aggregate content in asphalt mixtures according to the present invention is as follows:

[0051] In practical applications, representative samples of coarse aggregate from asphalt mixture stockpiles should be taken. The sampling method should refer to the "Specifications for Testing Aggregates in Highway Engineering" (JTGE42-2005). After washing, the coarse aggregate should be thoroughly dried at 100℃ for no less than 12 hours, while meeting the minimum sampling mass. After thorough mixing, the aggregate should be divided into three equal portions. The minimum sampling mass should meet the requirements in Table 1.

[0052] Table 1 Minimum Test Quantities for Coarse Aggregates of Different Specifications

[0053]

[0054]

[0055] The apparent density γ of each stone in the three samples was measured separately. 1i γ 2iγ 3i and mass m 1i m 2i m 3i The average apparent density of each sample of coarse aggregate was calculated and recorded as γ1, γ2, and γ3, and the mass of the coarse aggregate of the three samples was calculated and recorded as m1, m2, and m3, respectively.

[0056] in, In the formula, i is the number of each stone particle, ranging from 1 to n.

[0057] Stone particles with an apparent density ≥ γ1±0.1, γ2±0.1, or γ3±0.1 are defined as miscellaneous stone. The mass of miscellaneous stone in each sample of material is calculated and recorded as m1', m2', and m3'. In the formula, j is the stone number of the stone with apparent particle density ≥ γ1±0.1, γ2±0.1, or γ3±0.1.

[0058] The aggregate content Q of coarse aggregate in asphalt mixture stockpiles is calculated according to the following formula:

[0059]

[0060]

[0061]

[0062] The aggregate content Q of the coarse aggregate in the asphalt mixture is:

[0063] Taking three piles of aggregate as an example, the content of coarse aggregate in asphalt mixtures was tested using the method for testing the content of mixed aggregate in coarse aggregate provided by this invention and the traditional method of visual observation. The three piles of aggregate were: one pile composed of granite, diorite, and porphyry, another pile composed of basalt, and the third pile composed of diabase and diorite. The test results are shown in Table 2.

[0064] Table 2 Results of the test on the adhesion between ordinary asphalt and aggregate

[0065]

[0066]

[0067] As shown in Table 2, visual observation has a certain degree of differentiation for coarse aggregates with obvious color mixing, but this differentiation is subject to strong human subjectivity. Furthermore, it is difficult to effectively distinguish the content of mixed stones in coarse aggregates with indistinct color differentiation. In contrast, the method of this invention can clearly distinguish the degree of mixing of aggregates of different lithologies. It can also obtain better objective results for coarse aggregates with basically uniform color, and it does not require experience from the test personnel.

[0068] Taking a project using granite aggregate as an example, the test method for coarse aggregate content in asphalt mixtures provided by this invention was applied to test the apparent relative density of 10-20mm coarse aggregate entering the aggregate bin at different times. The test results are shown in Table 3.

[0069] Table 3. Results of apparent relative density test of coarse aggregate.

[0070] Test time Coarse aggregate specifications apparent relative density of coarse aggregate 2021.10.06 10~20mm 2.652 2021.10.10 10~20mm 2.640 2021.10.12 10~20mm 2.671 2021.10.13 10~20mm 2.638

[0071] As shown in Table 3, the apparent relative density of coarse aggregates entering the warehouse on different dates varies considerably, indicating poor stability. Therefore, this invention was used to test the aggregate content of coarse aggregates from different dates, and the results are shown in Table 4.

[0072] Table 4. Test Results of Coarse Aggregate Stone Content

[0073]

[0074]

[0075] As shown in Table 4, the apparent relative density of coarse aggregates entering the warehouse at different times varies greatly. The main reason is that the coarse aggregates have a large content of mixed stones and the coarse aggregates are unstable, resulting in large fluctuations in the apparent density of the coarse aggregates. The present invention quantitatively analyzes the content of coarse aggregates, which helps to analyze the stability of coarse aggregates and the reasons for their fluctuations.

[0076] Taking a project using granite aggregate as an example, Marshall specimens were formed at different times using the same molding method and their porosity was tested. The results are shown in Table 5.

[0077] Table 5. Results of the test on the apparent relative density of coarse aggregate.

[0078] Test time Theoretical maximum relative density of asphalt mixture Marshall specimen porosity / % 2022.09.06 2.504 3.2 2022.09.10 2.510 4.0 2022.09.12 2.521 6.5 2022.09.13 2.505 3.4

[0079] As shown in Table 5, the porosity of Marshall specimens with different molding processes varied considerably, although they all used the same molding method. Therefore, this invention was used to test the content of coarse aggregates and impurities from different dates, and the results are shown in Table 6.

[0080] Table 6. Results of Apparent Relative Density Test of Coarse Aggregates

[0081]

[0082]

[0083] As shown in Table 6, when the coarse aggregate content is low, the difference in the theoretical maximum relative density of the asphalt mixture is small, and the difference in the porosity of the Marshall specimens is also small. When the coarse aggregate content is high, the porosity of the Marshall specimens is high, and the difference in porosity between them and other specimens is also greater. This invention provides a reference for analyzing the variability of Marshall test results for asphalt mixtures. Furthermore, this invention can also ensure that the coarse aggregate content is within a reasonable range by detecting the coarse aggregate content, thereby guaranteeing the accuracy of related asphalt mixture tests.

[0084] The beneficial effects of this invention are as follows:

[0085] 1. The present invention provides a method for testing the content of coarse aggregate and miscellaneous stone in asphalt mixture. It provides a quantitative method for testing the content of miscellaneous stone. First, the density and mass of each stone in the coarse aggregate are tested. Then, the miscellaneous stones are distinguished according to the density and the content of miscellaneous stone is calculated. The test has less human factor and is more objective and accurate than the original visual observation.

[0086] 2. The present invention provides a method for testing the coarse aggregate content in asphalt mixtures. The apparent density of coarse aggregate is used as the distinguishing index for aggregates. Compared with indicators such as particle shape and color, it is more operable and objective, and the test results are more objective.

[0087] 3. The present invention provides a method for testing the coarse aggregate content in asphalt mixtures. The minimum sampling quantity varies for coarse aggregates of different specifications, which avoids repetitive operations, reduces the workload of the test, and ensures the accuracy and precision of the test.

[0088] 4. The method for testing the coarse aggregate content in asphalt mixtures provided by this invention is highly operable, easy to understand, and provides reliable data. It has a good ability to distinguish the degree of mixing of coarse aggregates of different lithologies and is a simple, easy-to-implement, and objective test method.

[0089] Example 2

[0090] To implement the method corresponding to Embodiment 1 above and achieve the corresponding functions and technical effects, a coarse aggregate content testing system for asphalt mixtures is provided below, such as... Figure 3 As shown, the system includes:

[0091] Module 1 is used to obtain the apparent density and mass of each stone in multiple coarse aggregate samples.

[0092] Calculation module 2 is used to calculate the average apparent density and total mass of each coarse aggregate sample based on the apparent density and mass of each stone.

[0093] The mixed stone quality determination module 3 is used to determine the mixed stone quality of each coarse aggregate sample based on the average apparent density of each sample and the apparent density and quality of each stone.

[0094] The mixed stone content determination module 4 is used to calculate the mixed stone content of coarse aggregate in asphalt mixture based on the mass of mixed stone in each sample of coarse aggregate and the total mass of each sample of coarse aggregate.

[0095] Example 3

[0096] This invention provides an electronic device, including a memory and a processor. The memory stores a computer program, and the processor runs the computer program to enable the electronic device to perform the method for testing the coarse aggregate content in asphalt mixtures according to Embodiment 1.

[0097] Optionally, the aforementioned electronic device may be a host computer.

[0098] In addition, this embodiment of the invention also provides a computer-readable storage medium storing a computer program that, when executed by a processor, implements the method for testing the coarse aggregate content in asphalt mixtures according to Embodiment 1.

[0099] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For the systems disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the descriptions are relatively simple; relevant parts can be referred to the method section.

[0100] This document uses specific examples to illustrate the principles and implementation methods of the present invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of the present invention. Furthermore, those skilled in the art will recognize that, based on the ideas of the present invention, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. A method for testing the coarse aggregate content in asphalt mixtures, characterized in that, The method includes: Obtain the apparent density and mass of each stone in multiple coarse aggregate samples; Based on the apparent density and mass of each stone, calculate the average apparent density and total mass of each coarse aggregate sample; The mass of the aggregate in each coarse aggregate sample is determined based on the average apparent density of each sample and the apparent density and mass of each individual stone, specifically including: Based on the average apparent density of each coarse aggregate sample and the apparent density of each stone, the type of each stone in each coarse aggregate sample is determined; the type includes mixed stones and non-mixed stones. Based on the mass of each stone, determine the mass of mixed stones in each sample of coarse aggregate; Based on the mass of aggregate in each coarse aggregate sample and the total mass of each coarse aggregate sample, the aggregate content of coarse aggregate in the asphalt mixture is calculated, specifically including: The content of miscellaneous stone in each coarse aggregate sample is calculated based on the mass of miscellaneous stone in each sample and the total mass of each sample. Based on the aggregate content of each coarse aggregate sample, the average aggregate content of multiple coarse aggregate samples is calculated to obtain the aggregate content of coarse aggregate in the asphalt mixture.

2. The method for testing the coarse aggregate content in asphalt mixtures according to claim 1, characterized in that, Each coarse aggregate sample must meet the minimum sampling weight requirements: 0.1 kg for coarse aggregate with a size of 5 mm to 10 mm; 0.5 kg for coarse aggregate with a size of 10 mm to 20 mm; and 1 kg for coarse aggregate with a size of 10 mm to 25 mm.

3. A system for testing the coarse aggregate content in asphalt mixtures, characterized in that, The system includes: The acquisition module is used to acquire the apparent density and mass of each stone in multiple coarse aggregate samples; The calculation module is used to calculate the average apparent density and total mass of each coarse aggregate sample based on the apparent density and mass of each stone. The aggregate quality determination module is used to determine the aggregate quality of each coarse aggregate sample based on the average apparent density of each sample and the apparent density and mass of each individual stone. Specifically, it includes: Based on the average apparent density of each coarse aggregate sample and the apparent density of each stone, the type of each stone in each coarse aggregate sample is determined; the type includes mixed stones and non-mixed stones. Based on the mass of each stone, determine the mass of mixed stones in each sample of coarse aggregate; The mixed aggregate content determination module is used to calculate the mixed aggregate content of coarse aggregate in asphalt mixtures based on the mixed aggregate mass of each coarse aggregate sample and the corresponding total mass of each coarse aggregate sample, specifically including: The content of miscellaneous stone in each coarse aggregate sample is calculated based on the mass of miscellaneous stone in each sample and the total mass of each sample. Based on the aggregate content of each coarse aggregate sample, the average aggregate content of multiple coarse aggregate samples is calculated to obtain the aggregate content of coarse aggregate in the asphalt mixture.

4. An electronic device, characterized in that, The device includes a memory and a processor, the memory being used to store a computer program, and the processor running the computer program to enable the electronic device to perform the method for testing the coarse aggregate content in asphalt mixtures according to any one of claims 1 to 2.

5. A computer-readable storage medium, characterized in that, It stores a computer program that, when executed by a processor, implements the method for testing the coarse aggregate content in asphalt mixtures as described in any one of claims 1 to 2.

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