Method for determining optimal asphalt dosage of recycled drainage asphalt mixture

Abstract

The invention discloses a method for determining the optimal asphalt dosage of a recycled drainage asphalt mixture. The method comprises the steps of determining a target void ratio; determining the blending rate A of the RAP material; determining the gradation of the recycled drainage asphalt mixture, and testing gradation parameters; and establishing a calculation model of the optimal asphalt consumption of the recycled drainage asphalt mixture, and substituting the obtained parameters into the model to calculate the optimal asphalt consumption of the recycled drainage asphalt mixture. According to the method, the target void ratio is introduced into the determination process of the optimal asphalt dosage of the recycled drainage asphalt mixture, so that the determination of the optimal asphalt dosage is more reasonable, meanwhile, the influence of the old material on the determination process of the optimal asphalt dosage of the recycled drainage asphalt mixture is considered, and the steps required for determining the optimal asphalt dosage are reduced; and the accuracy and the efficiency of determining the optimal asphalt dosage of the recycled drainage asphalt mixture are improved.

Description

Technical Field

[0001] The invention belongs to the field of asphalt mixture proportion design, and more specifically, relates to a method for determining an optimal asphalt dosage of a regenerated drainage asphalt mixture. Background Art

[0002] Determining the optimal asphalt dosage is an important part of the asphalt mixture design process, which has a significant impact on the road performance of the mixture. Too much asphalt will cause oil spills and other diseases, while too little asphalt will affect the durability of the mixture.

[0003] At present, the main difference between drainage asphalt mixture and other types of asphalt mixture is that it has a larger void ratio (18%-25%). The current standard method for determining the optimal asphalt dosage is to determine the upper limit of the optimal asphalt dosage of the mixture through a leakage test, and to determine the lower limit of the optimal asphalt dosage through a dispersion test. The standard method does not reflect the void ratio of the drainage asphalt mixture in the process of determining the optimal asphalt dosage. This also leads to the need to further ensure whether the void ratio is qualified after the optimal asphalt dosage is determined using the standard method. This step is cumbersome and there is a certain waste of materials. At the same time, there are certain differences in the properties of new and old materials in the recycled drainage asphalt mixture. It is necessary to consider their impact on the test results in the process of determining the optimal asphalt dosage of the recycled drainage asphalt mixture, so as to further improve the accuracy of the results of the optimal asphalt dosage of the recycled drainage asphalt mixture. Summary of the invention

[0004] In order to address the above technical problems, the present invention discloses a method for determining the optimal asphalt dosage of a recycled drainage asphalt mixture, which not only introduces the target void ratio into the process of determining the optimal asphalt dosage of the recycled drainage asphalt mixture, making the determination of the optimal asphalt dosage more reasonable, but also considers the influence of old materials on the process of determining the optimal asphalt dosage of the recycled drainage asphalt mixture and reduces the steps required to determine the optimal asphalt dosage, thereby improving the accuracy and efficiency of determining the optimal asphalt dosage of the recycled drainage asphalt mixture.

[0005] Technical solution:

[0006] Step 1, determining the target void fraction VV;

[0007] Step 2, determining the blending ratio A of the RAP material;

[0008] Step 3, determine the gradation of the recycled drainage asphalt mixture and test the gradation parameters, the gradation parameters include the compact density γ of the coarse aggregate j , effective density of synthetic mineral material γ 合成 , the content of asphalt in the old drainage asphalt mixture P b旧 , density of newly added asphalt γ 新沥青, old asphalt density γ 旧沥青 ;

[0009] Step 4: Establish a calculation model for the optimal asphalt dosage of the recycled drainage asphalt mixture, and calculate the optimal asphalt dosage P of the recycled drainage asphalt mixture based on the blending ratio A and grading parameters of the RAP material. 最佳 .

[0010] Step 4 further includes establishing a calculation model for the optimal asphalt dosage of the recycled drainage asphalt mixture;

[0011] According to the volume relationship between the components in the recycled drainage asphalt mixture, it can be obtained that:

[0012]

[0013] In the formula, m l Indicates the mass of recycled drainage asphalt mixture at the theoretical maximum density, m s Indicates the mass of the recycled drainage asphalt mixture in its actual state, γ l粗 It represents the density of coarse aggregate when the recycled drainage mixture is at the theoretical maximum density, P c It represents the proportion of coarse aggregate mass in recycled drainage asphalt mixture to the total mass of the mixture, m l剩余 It indicates the mass of the remaining components in the mixture except the coarse aggregate when the recycled drainage asphalt mixture is at the theoretical maximum density, m s剩余 It indicates the mass of the remaining components in the mixture except the coarse aggregate when the recycled drainage asphalt mixture is in the actual state, γ l It indicates the theoretical maximum density of recycled drainage asphalt mixture;

[0014] It is known that the volume parameters of recycled drainage asphalt mixture satisfy the following formula:

[0015]

[0016]

[0017]

[0018] x=P+P b旧 ×A

[0019] P 最佳 =P / (1-A)

[0020] In the formula, γ 沥青 represents the density of asphalt after the new and old asphalt are mixed in the recycled drainage asphalt mixture, x represents the total asphalt content of the recycled drainage asphalt mixture, and P represents the new asphalt content in the recycled drainage asphalt mixture;

[0021] The theoretical maximum density of recycled drainage asphalt mixture γ l , the mass of coarse aggregate in recycled drainage asphalt mixture accounts for the proportion of the total mass of the mixture P c , the density of asphalt after mixing new and old asphalt in recycled drainage asphalt mixtureγ 沥青 , the total asphalt content x of the recycled drainage asphalt mixture and the optimal asphalt content P of the recycled drainage asphalt mixture 最佳 Substituting the expression of into the expression of target void fraction VV, we can get:

[0022]

[0023] The calculation model for the optimal asphalt for recycled drainage asphalt mixture has been established.

[0024] Beneficial Effects

[0025] Compared with the prior art, the present invention has at least the following beneficial effects:

[0026] (1) The method for determining the optimal asphalt dosage of a regenerated drainage asphalt mixture of the present invention adds the target void ratio as a control index into the calculation process of the optimal asphalt dosage of the regenerated drainage asphalt mixture, which more fully considers the high void ratio characteristics of the regenerated drainage asphalt mixture and reflects the structural characteristics of the regenerated drainage asphalt mixture, making the determination process of the optimal asphalt dosage of the regenerated drainage asphalt mixture more reasonable.

[0027] (2) The method for determining the optimal asphalt dosage of a recycled drainage asphalt mixture of the present invention establishes a calculation model for the optimal asphalt dosage of the recycled drainage asphalt mixture based on the internal structural characteristics of the recycled drainage asphalt mixture. It not only takes into account the difference in properties between new and old materials in the recycled drainage asphalt mixture, but also reduces the steps required to determine the optimal asphalt dosage compared to conventional methods, thereby improving the accuracy and efficiency of determining the optimal asphalt dosage of the recycled drainage asphalt mixture. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The accompanying drawings in the specification, which constitute a part of the present invention, are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0029] Figure 1 It is a schematic diagram of the internal structure of the regenerated drainage asphalt mixture according to one or more embodiments of the present invention.

[0030] The reference numerals are as follows: 1. skeleton structure formed by coarse aggregate; 2. skeleton gap formed by coarse aggregate; 3. gap inside the mixture; 4. asphalt mortar; 5. fine aggregate DETAILED DESCRIPTION

[0031] The following examples will enable those skilled in the art to more fully understand the present invention, but are not intended to limit the present invention in any way.

[0032] The present invention discloses a method for determining an optimal asphalt dosage of a regenerated drainage asphalt mixture, the method comprising the following steps:

[0033] Step 1, determining the target void fraction VV;

[0034] Step 2, determining the blending ratio A of the RAP material;

[0035] Step 3, determine the gradation of the recycled drainage asphalt mixture and test the gradation parameters, the gradation parameters include the compact density γ of the coarse aggregate j , effective density of synthetic mineral material γ 合成 , the content of asphalt in the old drainage asphalt mixture P b旧 , density of newly added asphalt γ 新沥青 , old asphalt density γ 旧沥青 ;

[0036] Step 4: Establish a calculation model for the optimal asphalt dosage of the recycled drainage asphalt mixture, and calculate the optimal asphalt dosage P of the recycled drainage asphalt mixture based on the blending ratio A and grading parameters of the RAP material. 最佳 .

[0037] See also Figure 1 The method for determining the optimal asphalt dosage of the regenerated drainage asphalt mixture of the present invention specifically comprises the following steps:

[0038] S1. Determine the target void ratio VV. In this embodiment, the target void ratio of the regenerated drainage asphalt mixture is 20% according to the current requirements of the commonly used drainage asphalt pavement.

[0039] S2, determine the blending ratio A of the RAP material, in this embodiment, A is 30%;

[0040] S3, determine the gradation of the recycled drainage asphalt mixture, and test the gradation parameters, the gradation parameters include the compact density γ of the coarse aggregate j , effective density of synthetic mineral material γ 合成 , the content of asphalt in the old drainage asphalt mixture P b旧 , density of newly added asphalt γ 新沥青 , represents the old asphalt density γ 旧沥青 Table 1 shows the gradation of the recycled drainage asphalt mixture calculated according to the standard method in this embodiment, and the compact density γ of the coarse aggregate is obtained at the same time. j =1.67g / cm 3 , effective density of synthetic mineral material γ 合成 =2.88g / cm 3 , the content of asphalt in the old drainage asphalt mixture Pb旧 =4.25%, new asphalt density γ 新沥青 =1.05g / cm 3 , old asphalt density γ 旧沥青 =1.04g / cm 3 .

[0041] Table 1 Grading of recycled drainage asphalt mixture

[0042] Target void ratio 16 13.2 9.5 4.75 2.36 1.18 0.6 0.3 0.15 0.075 20％ 100 91.5 61.9 18.5 14.4 12.1 9.9 7.7 5.5 4.2 Upper limit of gradation 100 90.0 40.0 10.0 9.0 7.0 6.0 5.0 4.0 3.0 Lower limit of gradation 100 100.0 71.0 30.0 20.0 17.0 14.0 12.0 9.0 6.0 Median gradation 100 95.0 55.5 20.0 14.5 12.0 10.0 8.5 6.5 4.5

[0043] S4. Establish a calculation model for the optimal asphalt dosage of recycled drainage asphalt mixture. According to the volume relationship between the components in the recycled drainage asphalt mixture, the following can be obtained:

[0044]

[0045] In the formula, m l Indicates the mass of recycled drainage asphalt mixture at the theoretical maximum density, m s Indicates the mass of the recycled drainage asphalt mixture in its actual state, γ l粗 It represents the density of coarse aggregate when the recycled drainage mixture is at the theoretical maximum density, P c It represents the proportion of coarse aggregate mass in recycled drainage asphalt mixture to the total mass of the mixture, m l剩余 It indicates the mass of the remaining components in the mixture except the coarse aggregate when the recycled drainage asphalt mixture is at the theoretical maximum density, m s剩余 It indicates the mass of the remaining components in the mixture except the coarse aggregate when the recycled drainage asphalt mixture is in the actual state, γ l It indicates the theoretical maximum density of recycled drainage asphalt mixture;

[0046] It is known that the volume parameters of recycled drainage asphalt mixture satisfy the following formula:

[0047]

[0048]

[0049]

[0050] x=P+P b旧 ×A

[0051] P 最佳 =P / (1-A)

[0052] In the formula, γ 沥青 represents the density of asphalt after the new and old asphalt are mixed in the recycled drainage asphalt mixture, x represents the total asphalt content of the recycled drainage asphalt mixture, and P represents the new asphalt content in the recycled drainage asphalt mixture;

[0053] The theoretical maximum density of recycled drainage asphalt mixture γ l , the mass of coarse aggregate in recycled drainage asphalt mixture accounts for the proportion of the total mass of the mixture P c , the density of asphalt after mixing new and old asphalt in recycled drainage asphalt mixtureγ 沥青 , the total asphalt content x of the recycled drainage asphalt mixture and the optimal asphalt content P of the recycled drainage asphalt mixture 最佳 Substituting the expression of into the expression of target void fraction VV, we can get:

[0054]

[0055] The calculation model for the optimal asphalt dosage of recycled drainage asphalt mixture has been established. Based on the blending ratio A and grading parameters of the RAP material, the optimal asphalt dosage P of the recycled drainage asphalt mixture is calculated. 最佳 According to the grading in step 2, P 4.75 =18.5%, the compact density of coarse aggregate γ j , effective density of synthetic mineral material γ 合成 , the content of asphalt in the old drainage asphalt mixture P b旧 , P 4.75 New Asphalt Density γ 新沥青 , old asphalt density γ 旧沥青 Substituting into the calculation model, it can be calculated that when the target void ratio of the recycled drainage asphalt mixture is 20%, P 最佳 =4.6, and the corresponding oil-stone ratio is 4.6%.

[0056] The above are only preferred embodiments of the present invention, and the protection scope of the present invention is not limited to the above embodiments. All technical solutions under the concept of the present invention belong to the protection scope of the present invention. It should be pointed out that for ordinary technicians in this technical field, some improvements and modifications without departing from the principle of the present invention should be regarded as the protection scope of the present invention.

Claims

1. The present invention provides a method for determining the optimal asphalt dosage of recycled drainage asphalt mixture, characterized in that: The following steps are involved: Step 1, determining the target void fraction VV; Step 2, determining the blending ratio A of the RAP material; Step 3, determine the gradation of the recycled drainage asphalt mixture and test the gradation parameters, the gradation parameters include the compact density γ of the coarse aggregate j , effective density of synthetic mineral material γ 合成 , the content of asphalt in the old drainage asphalt mixture P b旧 , density of newly added asphalt γ 新沥青 , old asphalt density γ 旧沥青 ; Step 4: Establish a calculation model for the optimal asphalt dosage of the recycled drainage asphalt mixture, and calculate the optimal asphalt dosage P of the recycled drainage asphalt mixture based on the blending ratio A and grading parameters of the RAP material. 最佳 .

2. The method for determining the optimal asphalt dosage of recycled drainage asphalt mixture according to claim 1, characterized in that: Step 4 further includes establishing a calculation model for the optimal asphalt dosage of the recycled drainage asphalt mixture; According to the volume relationship between the components in the recycled drainage asphalt mixture, it can be obtained that: In the formula, m l Indicates the mass of recycled drainage asphalt mixture at the theoretical maximum density, m s Indicates the mass of the recycled drainage asphalt mixture in its actual state, γ l粗 It represents the density of coarse aggregate when the recycled drainage mixture is at the theoretical maximum density, P c It represents the proportion of coarse aggregate mass in recycled drainage asphalt mixture to the total mass of the mixture, m l剩余 It indicates the mass of the remaining components in the mixture except the coarse aggregate when the recycled drainage asphalt mixture is at the theoretical maximum density, m s剩余 It indicates the mass of the remaining components in the mixture except the coarse aggregate when the recycled drainage asphalt mixture is in the actual state, γ l It indicates the theoretical maximum density of recycled drainage asphalt mixture; The volume parameters of the recycled drainage asphalt mixture satisfy the following formula: x=P+P b旧 ×A P 最佳 =P / (1-A) In the formula, γ 沥青 represents the density of asphalt after the new and old asphalt are mixed in the recycled drainage asphalt mixture, x represents the total asphalt content of the recycled drainage asphalt mixture, and P represents the new asphalt content in the recycled drainage asphalt mixture; The theoretical maximum density of recycled drainage asphalt mixture γ l , the mass of coarse aggregate in recycled drainage asphalt mixture accounts for the proportion of the total mass of the mixture P c , the density of asphalt after mixing new and old asphalt in recycled drainage asphalt mixtureγ 沥青 , the total asphalt content x of the recycled drainage asphalt mixture and the optimal asphalt content P of the recycled drainage asphalt mixture 最佳 Substituting the expression of into the expression of target void fraction VV, we can get: The calculation model for the optimal asphalt dosage of recycled drainage asphalt mixture has been established.

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