A method for detecting the old material mixing amount of reclaimed asphalt mixture suitable for on-site
Patent Information
- Application Number
- CN202611275326.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-08-21
- Publication Date
- 2026-10-30
AI Technical Summary
但旧路面回收材料来源多样，老化程度不一，用于路面再生领域时存在困难
[0032]本申请提供一种适用于现场的再生沥青混合料旧料掺量检测方法。现有技术中由于缺乏含旧料再生沥青混合料融合区特征的系统研究，实践过程中尚无有效的旧料识别技术，本发明基于界面融合区特征识别和表征的掺量反演，提出一种适用于现场的再生沥青混合料旧料掺量检测方法，为获取路面养护工程中旧料的旧料掺量提供技术支撑；与传统老化评价方法相比，本发明分析了旧料中胶结料在微观尺度的老化梯度，采用分步抽提回收方法，构建新旧沥青融合区三层结构梯度模型，基于DSR进行流变性能测试，构建新旧沥青融合区三层梯度模型，结合FTIR测试所得亚砜指数以及复数剪切模量，计算三者变化率与产量之间的变化关系，明确混合沥青不同层位老化情况且其微观均匀性同样得到体现；和传统表征沥青老化的指标相比，通过对特征官能团及流变性能测试，量化混合沥青老化程度，实现对成分未知的掺量反演。
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Abstract
Description
Technical Field
[0001] This application relates to the field of asphalt testing technology, specifically to a method for on-site testing of the content of recycled asphalt mixtures. Background Technology
[0002] With the increasing demand for asphalt pavement maintenance and the vigorous promotion of pavement recycling technology in my country, in-situ thermal recycling maintenance projects, mainly based on remixing and overlaying, are receiving increasing attention. However, there is still no clear and effective engineering testing method for whether recycled materials are mixed into the overlay layer of asphalt pavement. Conducting relevant research on the quantitative estimation of the amount of recycled materials in recycled asphalt mixtures is a technical guarantee for promoting the standardization of the pavement recycling industry.
[0003] Domestic and international approaches to identifying the degree of asphalt aging in hot recycled asphalt mixtures primarily involve first recovering aged asphalt through solution extraction, and then testing the conventional performance indicators of individual asphalt to determine its aging degree. However, considering the uneven aging within the pavement, conventional performance indicators of a single asphalt cannot adequately evaluate its aging status. Furthermore, compared to the aging of individual asphalt, the aging of asphalt in a mixture is influenced by more factors and exhibits heterogeneity.
[0004] The current Chinese standard JTG E20-2011, "Test Procedures for Asphalt and Asphalt Mixtures in Highway Engineering," recommends using the Absen method and rotary evaporator method to recover asphalt from old pavement. However, the sources of recycled pavement materials are diverse, and their aging degrees vary, making their use in pavement recycling difficult. Existing research indicates that there is currently no unified standard for evaluating the technical performance of recycled asphalt mixtures.
[0005] The applicant discovered in their research that by utilizing the microscopic uniformity of asphalt mixtures, layered extraction and recovery of asphalt, and constructing a gradient model of the fusion zone through characteristic functional groups and rheological properties, the performance gradient of the fusion zone of new and old asphalt can be quantified, thereby achieving the purpose of quantitative estimation of the amount of recycled asphalt in recycled asphalt mixtures. Summary of the Invention
[0006] To address the shortcomings of existing technologies, this application provides a method for detecting the recycled asphalt mixture content in field applications. This method involves drilling core samples and extracting asphalt binder in layers. The sulfoxide index and the standard deviation of the complex shear modulus are obtained using Fourier transform infrared spectroscopy and dynamic shear rheology. The results are then compared with the content-standard deviation curves plotted from the test results of asphalt mixtures with different recycled asphalt mixture contents prepared in the laboratory, thereby determining the recycled asphalt mixture content in the field.
[0007] To achieve the above objectives, this application adopts the following technical solution:
[0008] This application provides a method for on-site testing of the content of recycled asphalt mixture aggregate, comprising the following steps:
[0009] S1. Drill a core sample of asphalt concrete from the site, heat the core sample to a preset temperature and then break it up to obtain a loose asphalt mixture.
[0010] S2. The loose asphalt mixture is extracted and recovered using a layered extraction method. During the extraction process, the core sample is radially divided into an inner layer, a middle layer, and an outer layer to obtain inner, middle, and outer asphalt binder samples.
[0011] S3. Fourier transform infrared spectroscopy and dynamic shear rheometer tests were performed on the inner, middle and outer asphalt binder samples.
[0012] S4. Calculate the sulfoxide index of each of the inner, middle and outer asphalt binders based on the Fourier transform infrared spectroscopy test results, and calculate the standard deviation of the sulfoxide index; obtain the complex shear modulus of the inner, middle and outer asphalt binders at 20℃ based on the dynamic shear rheometer test results, and calculate the standard deviation of the complex shear modulus.
[0013] S5. Indoor asphalt mixtures are prepared using the same aggregate mix ratio and asphalt type as the on-site recycled asphalt mixtures.
[0014] S6. The indoor asphalt mixture is subjected to short-term aging followed by long-term aging to obtain an indoor aged asphalt mixture.
[0015] S7. The indoor aged asphalt mixture is mixed with the unaged indoor prepared asphalt mixture in different proportions to form multiple groups of mixed asphalt mixture samples with different amounts of old material.
[0016] S8. Repeat steps S2 to S4 for each group of mixed asphalt mixture samples, obtain the standard deviation of the sulfoxide index corresponding to each group of mixed asphalt mixture samples, and plot the content-sulfoxide index standard deviation curve; obtain the standard deviation of the complex shear modulus corresponding to each group of mixed asphalt mixture samples, and plot the content-complex shear modulus standard deviation curve.
[0017] S9. Combining the dosage-sulfoxide index standard deviation curve and the dosage-complex shear modulus standard deviation curve, determine the amount of recycled material in the on-site recycled asphalt mixture based on the sulfoxide index standard deviation and complex modulus standard deviation measured in S4.
[0018] Preferably, in S1, the diameter of the core sample is 100mm-150mm, the depth of the core sample penetrates the recycled asphalt mixture layer and avoids crossing layers, the heating temperature is 60-80℃, and the dispersal is done manually or with a rubber hammer.
[0019] Preferably, in S2, the stratified extraction method involves first weighing 1000-1200g of loose on-site asphalt concrete core sample, and then immersing it sequentially in 300-500ml, 300-500ml, and 600-800ml of trichloroethylene solution for 5-10min, 5-10min, and 50-70min, respectively; the recovery process uses the Absen method to recover the asphalt sample from the three leachates.
[0020] Preferably, in S4, the method for calculating the sulfoxide index is as follows:
[0021]
[0022] In the formula: The sulfoxide index;
[0023] The area of the absorption peak near wavenumber 1030;
[0024] It is the sum of the areas of all characteristic peaks of asphalt.
[0025] Preferably, in S6, the short-term aging method involves placing the loose asphalt mixture in a ventilated oven at 135-140°C for 4-5 hours, and the long-term aging method involves placing the short-term aging sample in a ventilated oven at 85-90°C for 4-6 days after Marshall molding.
[0026] Preferably, in S7, the recycled material content is controlled at 0%, 10%, 20%, 30%, 60%, and 100%, and mixed with new material, forming six groups: A, B, C, D, E, and F, respectively, for the mixing of recycled asphalt mixtures with varying content. Preferably, in S8, the method for plotting the content-sulfoxide index standard deviation curve is as follows: obtain the sulfoxide index standard deviation corresponding to each group of mixed asphalt mixture samples, and plot the recycled material content of the mixed asphalt mixture sample on the x-axis and the corresponding sulfoxide index standard deviation on the y-axis. ， Plot the admixture content-sulfoxide index standard deviation curve; the method for plotting the admixture content-complex shear modulus standard deviation curve is as follows: obtain the complex shear modulus standard deviation corresponding to each group of mixed asphalt mixture samples, and plot the admixture content of the mixed asphalt mixture samples as the abscissa and the corresponding complex shear modulus standard deviation as the ordinate. ， Plot the standard deviation curve of dosage versus complex shear modulus.
[0027] Preferably, in S9, the method for determining the amount of recycled asphalt in the on-site recycled asphalt mixture is as follows:
[0028] The linear interpolation method was used to determine the doping level C1 corresponding to the standard deviation of the sulfoxide index based on the doping level-sulfoxide index standard deviation curve.
[0029] The dosage C2 corresponding to the standard deviation of the complex shear modulus was determined by using linear interpolation based on the dosage-complex shear modulus standard deviation curve.
[0030] The amount of recycled material is obtained by calculating the average value of C1 and C2.
[0031] Compared with the prior art, the beneficial effects of this application are as follows:
[0032] This application provides a method for detecting the content of recycled asphalt mixtures in field applications. Due to the lack of systematic research on the characteristics of the fusion zone of recycled asphalt mixtures containing recycled materials, there is currently no effective technology for identifying recycled materials in practice. This invention proposes a method for detecting the content of recycled asphalt mixtures in field applications based on the identification and characterization of interface fusion zone features, providing technical support for obtaining the content of recycled materials in road maintenance projects. Compared with traditional aging evaluation methods, this invention analyzes the aging gradient of the binder in the recycled material at the microscale, employs a stepwise extraction and recovery method, constructs a three-layer gradient model of the fusion zone between new and old asphalt, conducts rheological performance testing based on DSR, and combines the sulfoxide index and complex shear modulus obtained from FTIR testing to calculate the relationship between the rate of change of these three factors and the yield, clarifying the aging status of different layers of the mixed asphalt and demonstrating its microscopic uniformity. Compared with traditional indicators for characterizing asphalt aging, this invention quantifies the degree of aging of the mixed asphalt by testing characteristic functional groups and rheological properties, achieving content inversion for unknown components. Attached Figure Description
[0033] Figure 1 This invention provides an experimental procedure for a method of detecting the content of recycled asphalt mixture in on-site.
[0034] Figure 2 The standard deviation curve of doping level versus sulfoxide index in Example 1;
[0035] Figure 3 The curve showing the standard deviation of the dosage versus the complex shear modulus in Example 1 is shown. Detailed Implementation
[0036] To make the technical problems, technical solutions, and beneficial effects to be solved by this application clearer, the application will be further described in detail below with reference to embodiments. However, this should not be construed as limiting the scope of this application to the following examples. All other embodiments obtained by those skilled in the art without creative effort without departing from the above-described methodological spirit of this application are within the scope of protection of this application.
[0037] In this application, the terminology used is for the purpose of describing particular embodiments only and is not intended to be limiting of this application.
[0038] The singular forms “for,” “or,” “a,” “any,” and “the” used in this application are intended to include the plural forms unless the context clearly indicates otherwise.
[0039] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.
[0040] The following will describe in detail, with reference to different embodiments, a method for detecting the content of recycled asphalt mixture in field applications.
[0041] like Figure 1 As shown in the figure, this embodiment provides a method for on-site testing of the content of recycled asphalt mixture, including the following steps:
[0042] S1. Drill core samples of asphalt concrete from the road surface in service. The sample size is 100mm in diameter and 4cm in height. After the core samples are softened in an oven at 60℃ for 100min, they are crushed to a loose state using a rubber hammer to obtain loose asphalt mixture.
[0043] S2. The loose asphalt mixture is extracted and recovered using a layered extraction method. First, 1000g of loose on-site asphalt concrete core sample is weighed and then immersed in 300ml, 300ml and 600ml of trichloroethylene solution for 5min, 5min and 50min respectively to obtain inner layer, middle layer and outer layer asphalt binder samples.
[0044] S3. Fourier transform infrared spectroscopy and dynamic shear rheometer tests were performed on the inner, middle and outer asphalt binder samples.
[0045] S4. Calculate the sulfoxide index of each of the inner, middle, and outer asphalt binders based on the Fourier transform infrared spectroscopy test results, and calculate the standard deviation of the sulfoxide index based on the sulfoxide index; obtain the complex shear modulus of the inner, middle, and outer asphalt binders at 20℃ based on the dynamic shear rheometer test results, and calculate the standard deviation of the complex modulus based on the complex shear modulus; the specific method for calculating the sulfoxide index is as follows:
[0046]
[0047] In the formula: The sulfoxide index;
[0048] The area of the absorption peak near wavenumber 1030;
[0049] It is the sum of the areas of all characteristic peaks of asphalt.
[0050] S5. Indoor asphalt mixtures are prepared using the same aggregate mix ratio and asphalt type as the on-site recycled asphalt mixtures.
[0051] S6. The indoor asphalt mixture is subjected to short-term aging followed by long-term aging. The loose asphalt mixture obtained by mixing is first placed in a 135°C ventilated oven and heated for 4 hours. After short-term aging and molding, it is placed in an 85°C ventilated oven and heated for 4 days to obtain an indoor aged asphalt mixture.
[0052] S7. The indoor aged asphalt mixture is mixed with the unaged indoor prepared asphalt mixture in different proportions. The old material is controlled to have a dosage of 0%, 10%, 20%, 30%, 60%, and 100%. The mixture is then mixed with the new material and classified into six groups: A, B, C, D, E, and F. The mixed asphalt mixture with varying dosages is then mixed to form multiple groups of mixed asphalt mixture samples with different old material dosages.
[0053] S8. Repeat steps S2 to S4 for all six groups of mixed asphalt mixture samples (A, B, C, D, E, and F) to obtain the standard deviation of the sulfoxide index for each group of mixed asphalt mixture samples. Plot a curve of asphalt mixture content versus sulfoxide index standard deviation with the old aggregate content of the mixed asphalt mixture sample as the x-axis and the corresponding standard deviation of the sulfoxide index as the y-axis. Figure 2 As shown; obtain the standard deviation of the complex shear modulus at 20℃ for each group of mixed asphalt mixture samples, and plot the admixture content-complex shear modulus standard deviation curve with the admixture content of the mixed asphalt mixture samples as the abscissa and the corresponding standard deviation of the complex shear modulus at 20℃ as the ordinate, as shown. Figure 3 As shown;
[0054] S9. Combining the dosage-sulfoxide index standard deviation curve and the dosage-complex shear modulus standard deviation curve, determine the old material dosage of the on-site recycled asphalt mixture based on the sulfoxide index standard deviation and complex modulus standard deviation measured in S4.
[0055] The data from the core sample in step S4 are calculated and plotted in Table 1 below:
[0056] Table 1 shows the data of the field core samples in Example 1.
[0057]
[0058] As shown in Table 1, using linear interpolation, the dosage corresponding to the standard deviation of the sulfoxide index was determined to be 11.48% based on the dosage-sulfoxide index standard deviation curve; using linear interpolation, the dosage corresponding to the standard deviation of the complex shear modulus was determined to be 10.2% based on the dosage-complex shear modulus standard deviation curve; the average value of the corresponding dosages was calculated to obtain an estimated old material dosage of approximately 11%.
[0059] The above results demonstrate and describe the basic principles and main features of this application, as well as its advantages.
[0060] Those skilled in the art should understand that this application is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of this application. Various changes and modifications can be made to this application without departing from the spirit and scope thereof, and all such changes and modifications fall within the scope of this application as claimed. The scope of protection of this application is defined by the equivalents of the appended claims.
Claims
1. A method for on-site testing of the content of recycled asphalt mixture aggregate, characterized in that, Includes the following steps: S1. Drill a core sample of asphalt concrete from the site, heat the core sample to a preset temperature and then break it up to obtain loose asphalt mixture; S2. The loose asphalt mixture is extracted and recovered using a layered extraction method. During the extraction process, the core sample is radially divided into an inner layer, a middle layer, and an outer layer to obtain inner, middle, and outer asphalt binder samples. S3. Fourier transform infrared spectroscopy and dynamic shear rheometer tests were performed on the inner, middle and outer asphalt binder samples. S4. Calculate the sulfoxide index of each of the inner, middle and outer asphalt binders based on the Fourier transform infrared spectroscopy test results, and calculate the standard deviation of the sulfoxide index; obtain the complex shear modulus of the inner, middle and outer asphalt binders at 20℃ based on the dynamic shear rheometer test results, and calculate the standard deviation of the complex shear modulus. S5. Indoor asphalt mixtures are prepared using the same aggregate mix ratio and asphalt type as the on-site recycled asphalt mixtures. S6. The indoor asphalt mixture is subjected to short-term aging followed by long-term aging to obtain an indoor aged asphalt mixture. S7. The indoor aged asphalt mixture is mixed with the unaged indoor prepared asphalt mixture in different proportions to form multiple groups of mixed asphalt mixture samples with different amounts of old material. S8. Repeat steps S2 to S4 for each group of mixed asphalt mixture samples, obtain the standard deviation of the sulfoxide index corresponding to each group of mixed asphalt mixture samples, and plot the content-sulfoxide index standard deviation curve; obtain the standard deviation of the complex shear modulus corresponding to each group of mixed asphalt mixture samples, and plot the content-complex shear modulus standard deviation curve. S9. Combining the dosage-sulfoxide index standard deviation curve and the dosage-complex shear modulus standard deviation curve, determine the amount of recycled material in the on-site recycled asphalt mixture based on the sulfoxide index standard deviation and complex modulus standard deviation measured in S4.
2. The method for detecting the content of recycled asphalt mixture admixture in on-site according to claim 1, characterized in that, In S1, the diameter of the core sample is 100mm-150mm, and the depth of the core sample penetrates the recycled asphalt mixture layer; the heating temperature is 60-80℃ and the time is 100-120min, and the dispersal is done by a rubber hammer.
3. The method for detecting the content of recycled asphalt mixture admixture in on-site according to claim 1, characterized in that, In S2, the layered extraction method involves first weighing 1000-1200g of loose on-site asphalt concrete core sample, and then immersing it sequentially in 300-500ml, 300-500ml, and 600-800ml of trichloroethylene solution for 5-10min, 5-10min, and 50-70min, respectively.
4. The method for detecting the content of recycled asphalt mixture admixture in on-site according to claim 1, characterized in that, In S2, the recovery process employs the Absen method to recover bitumen samples from the tertiary leachate.
5. The method for detecting the content of recycled asphalt mixture admixture in on-site according to claim 1, characterized in that, In S4, the sulfoxide index is calculated using the following method: ； In the formula: The sulfoxide index; The absorption peak area at wavenumber 1030; It is the sum of the areas of all characteristic peaks of asphalt.
6. The method for detecting the content of recycled asphalt mixture admixture in on-site according to claim 1, characterized in that, In S6, the short-term aging method involves placing the loose asphalt mixture in a ventilated oven at 135-140°C and heating it for 4-5 hours.
7. The method for detecting the content of recycled asphalt mixture admixture in on-site according to claim 1, characterized in that, In S6, the long-term aging method involves placing the short-term aging sample, after Marshall molding, in a ventilated oven at 85-90°C for 4-6 days.
8. The method for detecting the content of recycled asphalt mixture admixture in on-site according to claim 1, characterized in that, In S7, the controlled dosage of recycled material is set to 0%, 10%, 20%, 30%, 60%, and 100%, and it is mixed with new material and divided into six groups: A, B, C, D, E, and F, respectively, for the mixing of recycled asphalt mixtures with varying dosages.
9. The method for detecting the content of recycled asphalt mixture admixture in on-site according to claim 1, characterized in that, In S8, the method for plotting the admixture content-sulfonyl index standard deviation curve is as follows: obtain the standard deviation of the sulfonyl index corresponding to each group of mixed asphalt mixture samples, and plot the old material admixture content of the mixed asphalt mixture sample as the abscissa and the corresponding standard deviation of the sulfonyl index as the ordinate. ， Plot the admixture content-sulfoxide index standard deviation curve; the method for plotting the admixture content-complex shear modulus standard deviation curve is as follows: obtain the complex shear modulus standard deviation corresponding to each group of mixed asphalt mixture samples, and plot the admixture content of the mixed asphalt mixture samples as the abscissa and the corresponding complex shear modulus standard deviation as the ordinate. ， Plot the standard deviation curve of dosage versus complex shear modulus.
10. A method for detecting the content of recycled asphalt mixture admixture in on-site, as described in claim 1, characterized in that, In S9, the method for determining the amount of recycled asphalt in the on-site recycled asphalt mixture is as follows: The linear interpolation method was used to determine the doping level C1 corresponding to the standard deviation of the sulfoxide index based on the doping level-sulfoxide index standard deviation curve. The dosage C2 corresponding to the standard deviation of the complex shear modulus was determined by using linear interpolation based on the dosage-complex shear modulus standard deviation curve. The amount of recycled material is obtained by calculating the average value of C1 and C2.