Method for evaluating performance of recycled aggregate hydraulic asphalt concrete

Abstract

The invention discloses a method for evaluating performance of recycled aggregate hydraulic asphalt concrete, which comprises the following steps of: determining sample data of four indexes including Marshall stability, Marshall flow value, splitting tensile strength and deformation under maximum force according to Marshall test and splitting test of asphalt concrete with different recycled aggregate substitution rates; establishing an initial evaluation index data matrix, performing homodromous processing on the data to obtain a processed standardized matrix, and calculating to obtain the weight of each index according to a variable coefficient method so as to calculate to obtain a weighted data matrix; carrying out comprehensive evaluation by using a TOPSIS method, calculating to obtain positive and negative ideal solutions, calculating to obtain relative proximity, and evaluating the comprehensive performance of the asphalt concrete under different recycled aggregate substitution rates according to a good and bad order of the relative proximity.

Description

Technical Field

[0001] The invention relates to the technical field of evaluation of recycled aggregate hydraulic asphalt concrete, and in particular to an evaluation method for the performance of recycled aggregate hydraulic asphalt concrete. Background Art

[0002] In recent years, recycled aggregates have been widely used in engineering projects, which not only effectively reduces the pressure on the environment caused by construction waste landfill, but also provides a sustainable alternative to natural aggregates. In order to efficiently utilize recycled aggregates and reduce the pollution caused by limestone mining to the environment, the feasibility of using abandoned concrete stones as raw materials for recycled aggregates in hydraulic asphalt concrete has been studied. It is necessary to explore the changes in the mechanical properties of asphalt concrete under different recycled aggregate replacement rates and select the optimal replacement rate. In the Marshall test and splitting test, it was found that different recycled aggregate replacement rates had significant differences in the performance of asphalt concrete, and the optimal replacement rates selected for each performance were often different. Therefore, it is necessary to conduct a detailed analysis of each performance to determine its importance and weight under different indicators. Through this analysis, the influence of different recycled aggregate replacement rates on the comprehensive performance of asphalt concrete can be more accurately evaluated, and an optimal comprehensive performance solution can be calculated accordingly.

[0003] In the prior art, the coefficient of variation method can effectively reveal the contribution of different indicators in the evaluation system by analyzing the degree of discreteness of data, thereby reducing the error caused by human intervention. This not only improves the scientificity and credibility of the decision-making process, but also provides a solid statistical basis for the reasonable evaluation of various indicators; the TOPSIS method (Technique for Order of Preference by Similarity to Ideal Solution) is an evaluation method widely used in multivariate decision-making. It ranks various options by calculating the minimum distance between the evaluation object and the ideal goal. The advantage of this method is that it can intuitively reflect the relative advantages and disadvantages of different schemes. However, when the TOPSIS method is used alone, there are also certain subjective problems, which are easily affected by personal preferences, making the evaluation results not comprehensive and accurate. In particular, in the sorting process, different schemes may approach the positive ideal point while also approaching the negative ideal point, which may lead to unreliable final results. In order to overcome these shortcomings, it is possible to consider combining the TOPSIS method with the coefficient of variation method. An evaluation method based on the distance between positive and negative ideal points can be adopted, and the contribution of each weighted indicator to the overall evaluation can be quantitatively evaluated at the same time. This combination method not only helps to enhance the accuracy of the results, but also ensures that the evaluation process is more comprehensive and objective. Combining the two analysis methods can better select the optimal replacement rate of recycled aggregate under different performance conditions. This process not only helps to guide the rational application of recycled aggregate, but also provides a scientific basis for optimizing the optimal replacement rate of recycled aggregate asphalt concrete, thereby promoting resource recycling and environmental protection while ensuring project quality. Summary of the invention

[0004] In order to solve the above technical problems, the present invention provides a method for evaluating the performance of recycled aggregate hydraulic asphalt concrete.

[0005] Calculating the weight of each indicator avoids the human error caused by subjective weighting and makes the calculation result more accurate.

[0006] To achieve the above object, the technical solution adopted by the present invention is as follows:

[0007] A method for evaluating the performance of recycled aggregate hydraulic asphalt concrete comprises the following steps:

[0008] S1. According to the performance evaluation standard of hydraulic asphalt concrete, multiple evaluation indicators are selected as indicators for measuring recycled aggregate asphalt concrete;

[0009] S2. Select the data of each evaluation index in the mechanical test sample of recycled aggregate asphalt concrete to establish an initial evaluation index data matrix , and the initial evaluation index data matrix The data in are homogenized to obtain the processed standardized matrix ;

[0010] S3. Obtaining a standardized matrix using the coefficient of variation method The weight of each indicator in ;

[0011] S4. According to the weight of each of the above indicators Standardized matrix Adjust to get the weighted data matrix ;

[0012] S5. Use TOPSIS method to weighted data matrix To conduct a comprehensive evaluation, first determine the reference point of all mechanical test samples, calculate the distance between each evaluation group and the reference point, and then calculate the positive and negative ideal solutions, as well as the relative proximity. , where the reference point is the sample point and the evaluation group is the positive and negative ideal solutions;

[0013] S6. Based on relative proximity The comprehensive performance of asphalt concrete under different recycled aggregate replacement rates was evaluated in order of advantages and disadvantages.

[0014] Preferably, the selected evaluation indicators include Marshall stability, Marshall flow value, splitting tensile strength and deformation under maximum force.

[0015] Preferably, the initial evaluation index data matrix established is As follows:

[0016] (1)

[0017] Where: is the number of samples to be evaluated, is the number of evaluation indicators, Performance data for materials;

[0018] matrix The data in is processed in the same direction by the following formula:

[0019] When processing, when the selected data The larger the reaction material, the better the performance. Is a positive indicator; when the selected data The smaller the material, the better the performance. Negative indicator.

[0020] when When it is a positive indicator: (2)

[0021] when When the index is negative: (3)

[0022] Where: is the initial matrix The OK The elements of the column, is the standardized matrix Middle OK Elements of a column.

[0023] Preferably, the above-mentioned standardized matrix The weight of each indicator in The steps to obtain are as follows:

[0024] S3.1, the standardized matrix is ​​calculated by the following formula The average value of the indicator and standard deviation :

[0025] (4)

[0026] (5);

[0027] S3.2. Calculate the coefficient of variation of each indicator by the following formula: :

[0028] (6);

[0029] S3.3: Weight of each indicator Using the coefficient of variation The calculation result is as follows:

[0030] (7).

[0031] The weighted data matrix obtained by the above adjustment It is expressed by the following formula: (8)

[0032] Weighted Data Matrix After the indicators in are positively transformed, the maximum values ​​of each indicator in all samples constitute a set of positive ideal solutions , the minimum values ​​of each index constitute a set of negative ideal solutions , the distance from the sample point to the optimal point The following definitions are given: (9) Distance from sample point to worst point The following definitions are given: (10)

[0033] Where: For the positive ideal solution Column elements, is the negative ideal solution Column elements, and therefore relative proximity The expression is as follows:

[0034] (11)

[0035] In the formula, The larger the value, the better the evaluation result of the evaluation object, so the relative proximity of multiple groups Sort and select the largest The replacement rate corresponding to the value is the optimal replacement rate of recycled asphalt concrete.

[0036] Compared with the prior art, the present invention has the following beneficial effects:

[0037] The present invention combines the coefficient of variation method with the TOPSIS method when evaluating the comprehensive performance of asphalt concrete under different recycled aggregate replacement rates, which can effectively determine the optimal replacement rate of recycled aggregate under different performance conditions. This process not only provides guidance for the rational application of recycled aggregate, but also provides a scientific basis for finding the optimal replacement rate of recycled aggregate in asphalt concrete, thereby promoting the recycling of resources and environmental protection while ensuring the quality of the project. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 It is a flowchart of the evaluation process of the present invention. DETAILED DESCRIPTION

[0039] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with embodiments and drawings. The exemplary embodiments of the present invention and their description are only used to explain the present invention and are not intended to limit the present invention.

[0040] When analyzing the results of the Marshall test and the splitting test, it was found that different performance indicators have their own optimal solutions. In order to determine the optimal replacement rate of recycled coarse aggregate, it is necessary to analyze the weights of each indicator. Therefore, it is necessary to introduce the coefficient of variation method into the analysis. It is an objective weighting method that calculates the weights of each indicator by statistically analyzing the collected data. The advantage of the coefficient of variation method lies in its high stability and reliability, which makes it possible to reduce errors caused by human intervention. In the decision-making process, the weights derived from data analysis not only improve the scientific nature of the evaluation, but also enhance the credibility of the results. Through this method, it is possible to clearly identify which indicators have a greater weight in the evaluation system, thereby providing a more accurate and objective basis for determining the optimal replacement rate of recycled coarse aggregate.

[0041] The TOPSIS method is a multivariate evaluation decision-making method that ranks by evaluating the degree of proximity between the evaluation object and the ideal goal. This method is very effective in dealing with complex decision-making problems, but it still has some defects at the theoretical level, especially in terms of subjectivity and reliability of results. In order to improve the rationality of the ranking of the TOPSIS method, the coefficient of variation method is combined with the TOPSIS method, namely the coefficient of variation TOPSIS method. As an objective weighting method, the coefficient of variation method can quantitatively evaluate the contribution of each weight indicator in the overall evaluation by analyzing data. This combination not only helps to solve the limitations of the TOPSIS method, but also makes up for the shortcomings that the coefficient of variation method may bring. Through this comprehensive method, we can consider the impact of each indicator more comprehensively and ensure more accurate and reliable results in the decision-making process. Ultimately, the coefficient of variation TOPSIS method will provide a more scientific tool for multivariate decision-making, enabling decision makers to make more reasonable and well-founded judgments when faced with complex choices.

[0042] Combining the coefficient of variation method with the TOPSIS method can effectively determine the optimal replacement rate of recycled aggregate under different performance conditions. This process not only provides guidance for the rational application of recycled aggregate, but also provides a scientific basis for finding the optimal replacement rate of recycled aggregate in asphalt concrete, thereby promoting resource recycling and environmental protection while ensuring project quality.

[0043] For this reason, the TOPSIS method for evaluating the performance of recycled aggregate hydraulic asphalt concrete disclosed in this embodiment is as follows: Figure 1 As shown, the following steps are included:

[0044] Step 1: Based on the Marshall test and splitting test of asphalt concrete with different recycled aggregate replacement rates, determine the sample data of the four indicators: Marshall stability, Marshall flow value, splitting tensile strength and deformation under maximum force.

[0045] Step 2: Set The evaluation index vector of asphalt concrete is ,in is Marshall stability; is the Marshall flow value; is the splitting tensile strength; Deformation under maximum force.

[0046] In the test scheme of this embodiment, five groups of asphalt concrete with different recycled coarse aggregate replacement rates are designed, and the evaluation matrix is ​​expressed as , then the weight of each group of asphalt concrete evaluation index is .

[0047] Step 3: Use formula 2 and formula 3 to calculate the matrix After isotropic and dedimensionalization, the standard matrix as follows:

[0048]

[0049] The coefficient of variation method is used to calculate the standardized matrix using formulas 4-7 The average value, standard deviation, coefficient of variation and weight of each indicator See Table 1:

[0050] Table 1 is the calculation table of performance index weights of hydraulic asphalt concrete with different replacement rates of recycled coarse aggregate

[0051]

[0052] As can be seen from Table 1, the standardized matrix The weight order of each index is Marshall flow value > Marshall stability > splitting tensile strength > deformation under maximum force.

[0053] Step 4: According to the standardized matrix The weights of each indicator in the formula are adjusted by combining formula 1 and 6 to obtain the weighted data matrix as follows:

[0054]

[0055] Step 5: Use TOPSIS method to weight the data matrix Conduct a comprehensive evaluation, specifically, a weighted data matrix After the indicators in are positively transformed, the maximum values ​​of each indicator in all samples constitute a set of positive ideal solutions , the minimum values ​​of each index constitute a set of negative ideal solutions , see the following formula for details:

[0056]

[0057] Use formulas 9-10 to calculate the distance from the sample point to the optimal point And the distance from the sample point to the worst point , as follows:

[0058]

[0059] Finally, the relative proximity is calculated by formula 11 , and according to The comprehensive performance of 5 groups of different asphalt concretes were evaluated in order of merit and demerit. The evaluation results are shown in Table 2:

[0060] Table 2 shows the comprehensive performance evaluation results of recycled coarse aggregate asphalt concrete with different replacement rates

[0061]

[0062] The evaluation results in Table 2 show that when the replacement rate of recycled coarse aggregate is 50% in the comprehensive evaluation ranking of the TOPSIS method, the comprehensive performance of the recycled aggregate asphalt concrete is the highest, followed by the asphalt concrete with a replacement rate of 100% recycled coarse aggregate. When the replacement rate of recycled coarse aggregate is 25%, the performance of the asphalt concrete is the worst.

[0063] Therefore, the coefficient of variation TOPSIS method was used to optimize the performance of asphalt concrete when the replacement rate of recycled coarse aggregate was 50%.

[0064] Of course, the present invention may have many other embodiments. Without departing from the spirit and essence of the present invention, technicians familiar with the field may make various corresponding changes and modifications based on the present invention, but these corresponding changes and modifications should all fall within the scope of protection of the claims attached to the present invention.

Claims

1. A method for evaluating the performance of recycled aggregate hydraulic asphalt concrete, characterized in that: The steps include: S1. According to the performance evaluation standard of hydraulic asphalt concrete, multiple evaluation indicators are selected as indicators for measuring recycled aggregate asphalt concrete; S2. Select the data of each evaluation index in the mechanical test sample of recycled aggregate asphalt concrete to establish an initial evaluation index data matrix , and the initial evaluation index data matrix The data in are homogenized to obtain the processed standardized matrix ; S3. Obtaining a standardized matrix using the coefficient of variation method The weight of each indicator in ; S4. According to the weight of each of the indicators Standardize the matrix Adjust to get the weighted data matrix ; S5. Use TOPSIS method to weighted data matrix To conduct a comprehensive evaluation, first determine the reference point of all mechanical test samples, calculate the distance between each evaluation group and the reference point, and then calculate the positive and negative ideal solutions, as well as the relative proximity. , where the reference point is the sample point and the evaluation group is the positive and negative ideal solutions; S6. Based on relative proximity The comprehensive performance of asphalt concrete under different recycled aggregate replacement rates was evaluated in order of advantages and disadvantages.

2. The method for evaluating the performance of recycled aggregate hydraulic asphalt concrete according to claim 1, characterized in that: The evaluation indicators selected in step 1 include Marshall stability, Marshall flow value, splitting tensile strength and deformation under maximum force.

3. The method for evaluating the performance of recycled aggregate hydraulic asphalt concrete according to claim 2, characterized in that: The initial evaluation index data matrix established As follows: （1） Where: is the number of samples to be evaluated, is the number of evaluation indicators, Performance data for materials; matrix The data in is processed in the same direction by the following formula: when When it is a positive indicator: （2） when When the index is negative: （3） Where: is the initial matrix The OK Elements of the column, is the standardized matrix Middle OK Elements of a column.

4. The method for evaluating the performance of recycled aggregate hydraulic asphalt concrete according to claim 3, characterized in that: The normalized matrix The weight of each indicator in The steps to obtain are as follows: S3.1, the standardized matrix is ​​calculated by the following formula The average value of the indicator and standard deviation : （4） （5）； S3.

2. Calculate the coefficient of variation of each indicator by the following formula: : （6）； S3.3: Weight of each indicator Using the coefficient of variation The calculation result is as follows: （7）。 5. The method for evaluating the performance of recycled aggregate hydraulic asphalt concrete according to claim 4, characterized in that: The weighted data matrix obtained by adjusting It is expressed by the following formula: （8）。 6. The method for evaluating the performance of recycled aggregate hydraulic asphalt concrete according to claim 5, characterized in that: Weighted Data Matrix After the indicators in are positively transformed, the maximum values ​​of each indicator in all samples constitute a set of positive ideal solutions , the minimum values ​​of each index constitute a set of negative ideal solutions , the distance from the sample point to the optimal point The following definitions are given: （9） The distance from the sample point to the worst point The following definitions are given: （10） Where: For the positive ideal solution Column elements, is the negative ideal solution Column elements, and therefore relative proximity The expression is as follows: （11）。 7. The method for evaluating the performance of recycled aggregate hydraulic asphalt concrete according to claim 6, characterized in that: Relative proximity of multiple groups Sort by the largest The replacement rate corresponding to the value is the optimal replacement rate of recycled asphalt concrete.

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