A process for detecting the rubber powder content in rubber asphalt

Abstract

This invention discloses a process for detecting the rubber powder content in rubberized asphalt, comprising: 1) determining the processing parameters and design dosage of rubberized asphalt; 2) preparing five groups of rubberized asphalt according to the given processing parameters using the design rubber powder dosage, design rubber powder dosage ±4%, and design rubber powder dosage ±8%; 3) assembling a functionalized rubber powder extraction device; 4) extracting the residual rubber powder content from the five groups of rubberized asphalt and obtaining a curve relationship between the swollen rubber powder content and the rubber powder dosage; 5) extracting the residual rubber powder content from the rubberized asphalt to be tested and obtaining its swollen rubber powder content; 6) substituting the swollen rubber powder content in the rubberized asphalt to be tested into the curve relationship formula of the standard sample to obtain the rubber powder content in the sample to be tested. This invention can effectively detect the original rubber powder dosage, the swollen rubber powder content, and the residual rubber powder content in rubberized asphalt, which not only improves the means of quality control of rubberized asphalt but also provides technical support for the research and development of waste tire rubber powder asphalt.

Description

Technical Field

[0001] This invention relates to the field of materials testing technology, specifically to a process method for detecting the content of rubber powder in rubber asphalt. Background Technology

[0002] The recycling of waste rubber materials is a green and environmentally friendly technology that aligns with sustainable development strategies. Numerous studies have shown that processing waste tires into rubber powder and adding it to asphalt for paving asphalt pavements not only achieves resource recycling and efficient utilization of waste tires, but also significantly improves the long-term performance of asphalt pavements, extends their service life, and reduces construction and maintenance costs, resulting in significant social, environmental, and economic benefits. In recent years, with the development of science and technology, rubber asphalt has become the most widely used modified asphalt in highway asphalt pavement engineering, second only to SBS modified asphalt.

[0003] The performance of rubberized asphalt is not only limited by the properties of its raw materials but also closely related to its processing parameters. Among these parameters, the amount of rubber powder added is a crucial parameter in practical applications, directly affecting both performance changes and economic efficiency. The fundamental reason why adding rubber powder to asphalt achieves modification is that the rubber powder absorbs the oil in the asphalt and undergoes a swelling reaction, thereby altering the asphalt's properties. If the amount of rubber powder added is too small, the modification effect on the asphalt will be insignificant; however, if the amount added is too large, insufficient swelling will result in poor modification due to a lack of lightweight components in the asphalt. Therefore, in the application of rubberized asphalt, it is of great significance to rationally control the content of residual rubber powder and the original amount of rubber powder to regulate its comprehensive performance indicators.

[0004] However, the control of rubber powder content can only be monitored before rubber asphalt processing. The detection of residual rubber powder content and the content of rubber powder in swollen parts of finished rubber asphalt is still lacking, which seriously restricts the development of quality control and application technology of waste tire rubber powder rubber asphalt. Summary of the Invention

[0005] The purpose of this invention is to address the problems in the prior art by providing a process for detecting the rubber powder content in rubber asphalt. This method can effectively detect the original rubber powder content, the content of swollen rubber powder, and the content of remaining rubber powder in rubber asphalt. It not only improves the method for quality control of rubber asphalt in practical applications but also provides technical support for the research and development of asphalt modified from waste tire rubber powder.

[0006] In this invention, the following definitions apply: the amount of rubber powder in rubber asphalt is the mass ratio of asphalt, including the amount of raw rubber powder added, the proportion of swollen rubber powder, and the proportion of residual rubber powder; the amount of raw rubber powder added refers to the designed amount of rubber powder to be added before processing the rubber asphalt; the proportion of swollen rubber powder refers to the desulfurized, depolymerized, and swollen portion of rubber powder in the final processed rubber asphalt; the proportion of residual rubber powder refers to the undesulfurized, depolymerized, and swollen portion of rubber powder in the final processed rubber asphalt, which exists in the rubber asphalt in particulate form.

[0007] In this invention, the amount of rubber powder in rubber asphalt is the percentage of the mass of rubber powder to the mass of asphalt; the content of residual rubber powder in rubber asphalt is the percentage of the mass of residual rubber powder to the mass of added rubber powder; and the content of swollen rubber powder in rubber asphalt is the percentage of the mass of swollen rubber powder to the mass of added rubber powder.

[0008] To achieve the above-mentioned objectives, the technical solution of this invention is as follows: A process for detecting the rubber powder content in rubber asphalt, comprising the following steps:

[0009] Step 1: Determine the processing parameters and design dosage of rubber asphalt;

[0010] Step 2: Prepare more than 5 groups of rubber asphalt according to the given processing parameters, using the designed rubber powder content, the designed rubber powder content ±4%, and the designed rubber powder content ±8%.

[0011] Step 3: Assemble the functional assembly device for the adhesive powder extraction device;

[0012] Step 4: Extract the remaining rubber powder content from more than 5 groups of rubber asphalt and obtain the curve relationship between the swollen rubber powder content and the rubber powder dosage;

[0013] Step 5: Extract the remaining rubber powder content from the rubber asphalt to be tested, and obtain its swollen rubber powder content;

[0014] Step 6: Substitute the content of swollen rubber powder in the rubber asphalt to be tested into the standard sample curve formula to obtain the amount of rubber powder in the sample to be tested.

[0015] Furthermore, in step 3, the functional assembly of the adhesive powder extraction device includes, from top to bottom, a cooling section located at the top of the device, an extraction section in the middle, and a heating section located at the bottom.

[0016] Furthermore, in the cooling section, the cooling device is a glass spherical condenser tube, with one end of the condenser tube connected to a water inlet by a latex hose and the other end connected to a drain tank; the condenser tube can be used individually or in series to conduct multiple tests simultaneously.

[0017] Furthermore, in the extraction section, the extraction device is a 100ml glass extractor connected to a condenser tube at the top and a 250ml flat-bottomed single-necked flask at the bottom.

[0018] Furthermore, the heating part is a flat-bottomed single-necked flask, which is heated by a constant-temperature oil bath with a heating temperature range of 20℃ to 200℃. The constant-temperature oil bath has a reserved opening for placing the flat-bottomed single-necked flask. During use, the depth of immersion of the flat-bottomed single-necked flask in the oil bath should be greater than the height of the liquid in the flask to ensure that the sample liquid is at a suitable temperature during operation.

[0019] Furthermore, in step 4, the specific expression of the formula for calculating the rubber powder content in the extraction of residual rubber powder from rubber asphalt is as shown in equation (1):

[0020]

[0021] Where: w—residual rubber powder content in rubber asphalt (wt%);

[0022] x — Rubber powder content in rubber asphalt (%);

[0023] m0 — Mass of dried filter paper (g);

[0024] m1 — Mass of rubber asphalt and filter paper before extraction (g);

[0025] m2 — Mass of extracted rubber asphalt and filter paper (g);

[0026] Furthermore, in step 4, the extraction step of the remaining rubber powder in the rubber asphalt is as follows:

[0027] T1. Soak the required filter paper in a clean tetrahydrofuran solution for 1 hour, then dry it in an oven at 105℃±5℃, weigh it and record the weight m0. The weighing accuracy is 0.001g.

[0028] T2. Heat the rubber asphalt to a molten state and stir it evenly. Place filter paper on the weighing platform of the electronic balance and weigh about 5g of rubber asphalt sample m1. The weighing accuracy is 0.001g.

[0029] T3. Fold the filter paper to seal the asphalt sample tightly, and then immerse it completely in tetrahydrofuran solution for 12 hours.

[0030] T4. Assemble the functional assembly device for extraction (S1). Put 130 ml of clean tetrahydrofuran solution into a flat-bottomed single-necked flask and put the soaked sample into the extractor.

[0031] T5. Set the oil bath temperature to 150℃, turn on the oil bath heating and condenser water circulation functions, and distill to extract the remaining rubber powder particles in the rubber asphalt. Stop the distillation extraction when the filter paper wrapped with the sample turns white or light yellow and the color does not change for 30 minutes.

[0032] T6. Remove the filter paper and sample after distillation and place them in an oven at 105℃±5℃ to dry. Then weigh them (m2) with a weighing accuracy of 0.001g.

[0033] T7. Calculate the residual rubber powder content w in rubber asphalt according to formula (1).

[0034] Furthermore, during the heating process of the apparatus in step T5, ensure that the solution in the flat-bottomed single-necked flask evaporates smoothly, that is, there should be a solution in the extractor that submerges the sample. Otherwise, the existing mixed solution in the flat-bottomed single-necked flask can be replaced with a new tetrahydrofuran solution.

[0035] Furthermore, the entire experimental process should be conducted within a sealed fume hood to prevent the release of harmful gases.

[0036] Furthermore, in step 4, the fitting formula used to prepare the standard curve of rubber powder content in rubber asphalt is specifically expressed as equation (2), and the correlation coefficient R of the fitted curve is... 2 Not less than 0.98.

[0037] w1=ax+b (2)

[0038] w1 = 100% - w (3)

[0039] Where: w—residual rubber powder content in rubber asphalt (%);

[0040] x — Rubber powder content in rubber asphalt (%);

[0041] W1—Content of swollen rubber powder in rubber asphalt (%);

[0042] a and b are constants.

[0043] Furthermore, in step 4, the plotting of the standard curve for the rubber powder content in rubber asphalt includes the following steps:

[0044] 1) Five groups of rubber asphalt were prepared according to the given processing parameters using the designed rubber powder content, the designed rubber powder content ±4%, and the designed rubber powder content ±8%.

[0045] 2) According to the extraction steps of the residual rubber powder in rubber asphalt as described in claim 8, the residual rubber powder in 5 groups of rubber asphalt is extracted respectively, and the content of residual rubber powder in each group is calculated.

[0046] 3) Take the obtained data, with the rubber powder content in rubber asphalt as the variable and the residual rubber powder content in rubber asphalt as the dependent variable, and perform linear relationship fitting according to formula (2) to obtain the standard curve calculation formula under certain processing parameters and material constraints.

[0047] Furthermore, the given processing parameters include: the type and grade of asphalt used in rubber asphalt processing, the type and grade of rubber powder, the method of adding rubber powder, the temperature, time, stirring rate, and shear rate of rubber asphalt processing, and the additives added during rubber asphalt processing.

[0048] Furthermore, in the process method for detecting the rubber powder content in the rubber asphalt, the residual rubber powder content w obtained from the rubber asphalt to be tested is substituted into the standard curve calculation formula 2 to calculate the design rubber powder content x, and then the swelling rubber powder content W1 in the rubber asphalt is obtained using formula 3.

[0049] The beneficial effects of this invention are: This invention provides a process method for detecting the original amount of rubber powder, the content of rubber powder in the swollen part, and the content of residual rubber powder in rubber asphalt. The method is highly operable and accurate in measurement, which adds a means of quality control for rubber asphalt and greatly promotes the research and development of waste tire rubber powder modified asphalt technology. Attached Figure Description

[0050] Figure 1 : A schematic diagram of the functionalized assembly structure of the adhesive powder extraction device in this embodiment of the invention;

[0051] Figure 2 : Flowchart of the process for detecting the rubber powder content in rubber asphalt in this embodiment of the invention;

[0052] Figure 3 : Standard curve of adhesive powder content in Example 1 of this invention;

[0053] Figure 4 : Standard curve of adhesive powder content in Example 2 of this invention;

[0054] Figure 5 : Standard curve of adhesive powder content in Example 3 of this invention;

[0055] In the diagram: 1-Cooling section; 2-Extraction section; 3-Heating section; 4-Oil bath equipment. Detailed Implementation

[0056] The present invention will be further described in detail below with reference to specific embodiments.

[0057] Example 1:

[0058] The rubber powder content in a rubber-modified asphalt was determined according to the method for detecting rubber powder content of the present invention.

[0059] Given: A certain project uses rubber asphalt, sample number AR1, the designed rubber powder content of the rubber asphalt is 18%; the materials used are Hubei Guochuang No. 70 Grade A road petroleum asphalt and Guangxi Qinzhou rubber powder; the processing parameters of the rubber asphalt are: 1) put the road petroleum asphalt into the oven and heat it to the molten state, then add the rubber powder, and stir at (190±5)℃ for (30±5)min; 2) set the shearing rate of the shearing machine to 4000r / min, and continuously shear the product in 1) at (190±5)℃ for (30±5)min; 3) let the product in 2) develop at 140℃ for (30±5)min.

[0060] Test Procedure: 1. Prepare five groups of rubber asphalt (x1, x2, x3, x4, x5) with different rubber powder contents (10%, 14%, 18%, 22%, 26%) according to the given rubber asphalt processing parameters; 2. Prepare six sheets of filter paper, immerse them in 200ml of tetrahydrofuran solution for 1 hour, remove them, dry them, and weigh them (m01, m02, m03, m04, m05); 3. Weigh a certain mass of rubber asphalt (m11, m12, m13, m14, m15), wrap and seal it with the treated filter paper, and then completely immerse it in tetrahydrofuran solution. 1. After 12 hours; 2. Place the product from step 3 into the extractor assembled with functionalized extraction, set the oil bath temperature to 150℃, turn on the oil bath heating and condenser water circulation functions, and distill to extract the remaining rubber powder particles in the rubber asphalt. Stop the distillation extraction when the filter paper wrapped with the sample turns white or light yellow and the color does not change for 30 minutes; 3. Take out the filter paper and sample after distillation and place them in an oven at 105℃±5℃ to dry and weigh them (m21, m22, m23, m24, m25); 4. Take samples of rubber asphalt AR1 and test them according to the above test steps (2~5). The residual rubber powder content in five groups of rubber asphalt and AR1 with different rubber powder contents was calculated according to formula (1). The rubber powder content in the rubber asphalt (10%, 14%, 18%, 22%, 26%) was used as the variable, and the amount of sol-rubber powder in the rubber asphalt was used as the dependent variable. A linear relationship was fitted according to formula (4) to obtain the standard curve calculation formula (4) under specific processing parameters and material limitations. Then, the residual rubber powder content in the measured sampled rubber asphalt AR1 was substituted into formula (4) to calculate its rubber powder content and swollen rubber powder content. The obtained experimental data and calculation results are shown in Table 1, and the fitted curve is shown in... Figure 3 .

[0061] Table 1. List of Experimental Data

[0062]

[0063] w1 = -1.3073x + 40.159 R 2 =0.9919 (4)

[0064] Based on the test and calculation results in Table 1, the required dosage of rubber asphalt (sampling number AR1) used in this project is: x AR1 = (18.1% + 17.8%) / 2 = 18.0%.

[0065] Example 2:

[0066] Compared with Example 1, the modified asphalt made from recycled tire rubber powder provided in this example includes, by weight, the following raw materials: SK-90# base asphalt from South Korea.

[0067] The rubber powder content in a rubber-modified asphalt was determined according to the method for detecting rubber powder content of the present invention.

[0068] Given: A certain project uses rubber asphalt, sample number AR2, and the designed rubber powder content of the rubber asphalt is 20%; the materials used are SK-90A grade road petroleum asphalt from South Korea, rubber powder from Wuwei, Gansu, and a certain vitamin binder (the content is 4.0% of the rubber powder mass); the processing parameters of the rubber asphalt are: 1) Heat the road petroleum asphalt in an oven to a molten state, then add the uniformly mixed rubber powder and a certain vitamin binder, and stir at (190±5)℃ for (30±5) min; 2) Set the shearing rate of the shearing machine to 5000 r / min, and continuously shear the product in 1) at (195±5)℃ for (60±5) min; 3) Stir the product in 2) at (195±5)℃ for (30±5) min; 4) Let the product in 3) mature at 150℃ for (30±5) min. Other steps and process parameters are the same as in Example 1. The obtained experimental data and calculation results are shown in Table 2, and the fitted curve is shown in Table 2. Figure 4 .

[0069] Table 2 List of Experimental Data

[0070]

[0071]

[0072] w1 = -1.3026x + 38.173 R 2 =0.9891 (5)

[0073] Based on the test results in Table 2, the dosage of rubber asphalt (sampling number AR2) used in this project is determined to be: x AR2 = (19.5% + 19.4%) / 2 = 19.4%.

[0074] Example 3:

[0075] Compared with Example 1, this example provides a modified asphalt made from recycled tire rubber powder, with raw materials in parts by weight.

[0076] The rubber powder content in a rubber-modified asphalt was determined according to the method for detecting rubber powder content of the present invention.

[0077] Given: A certain project uses rubberized asphalt, sample number AR3, the designed rubber powder content of which is 18%; the materials used are COSCO Shipping's No. 70 Grade A road petroleum asphalt, Guangxi Wuming rubber powder, COSCO Shipping's SBS(ID) modified asphalt (4% of the asphalt mass), additive A (5.0% of the rubber powder mass), and additive B (3.5% of the rubber powder mass); the rubberized asphalt processing parameters are: 1) Place the road petroleum asphalt and SBS(ID) modified asphalt separately in an oven and heat... 1) Mix thoroughly until molten; 2) Add rubber powder and additive A, stir at (190±5)℃ for (30±5) min; 3) Set the shearing rate of the shearing machine to 4000 r / min, and continuously shear the product in step 2) at (190±5)℃ for (30±5) min; 4) Add rubber powder and additive B to the product in step 3), stir at (195±5)℃ for (30±5) min; 5) Let the product in step 4) mature at 150℃ for (30±5) min. Other steps and process parameters are the same as in Example 1. The obtained experimental data and calculation results are shown in Table 3, and the fitting curve is shown in Table 3. Figure 5 .

[0078] Table 3. List of Experimental Data

[0079]

[0080]

[0081] w1 = -1.2828x + 42.436 R 2 =0.9872 (6)

[0082] Based on the test results in Table 3, the dosage of rubber asphalt (sampling number AR3) used in this project is: x AR2 = (18.4% + 18.6%) / 2 = 18.5%.

[0083] The detection process of this invention is simple to operate, low in cost, highly practical, and accurate in measurement. It enables the control of the admixture parameters of rubber asphalt during application, and provides technical support for the research and development of asphalt modified from waste tire rubber powder.

[0084] Although the present invention has been described in detail above with specific embodiments, modifications or improvements can be made to it, which will be obvious to those skilled in the art. Therefore, all such modifications or improvements made without departing from the spirit of the present invention fall within the scope of protection claimed by the present invention.

Claims

1. A process for detecting the rubber powder content in rubberized asphalt, characterized in that, Includes the following steps: Step 1: Determine the processing parameters and design dosage of rubber asphalt; Step 2: Prepare more than 5 groups of rubber asphalt according to the designed rubber powder content, the designed rubber powder content ±4%, and the designed rubber powder content ±8% and the given processing parameters; Step 3: Assemble the functional assembly device for the adhesive powder extraction device; Step 4: Extract the remaining rubber powder content from more than 5 groups of rubber asphalt and obtain the curve relationship between the swollen rubber powder content and the rubber powder dosage; The specific expression of the relationship between the rubber powder content curve in rubber asphalt is shown in equation (2), and the correlation coefficient R of the fitted curve is... 2 Not less than 0.98; ； Where: x — rubber powder content in rubber asphalt (%); W – Residual rubber powder content in rubber asphalt (%) W1—Content of swollen rubber powder in rubber asphalt (%); a and b are constants; Step 5: Extract the remaining rubber powder content from the rubber asphalt to be tested, and obtain its swollen rubber powder content; Step 6: Substitute the content of swollen rubber powder in the rubber asphalt to be tested into the standard sample curve relationship to obtain the amount of rubber powder in the sample to be tested. The rubber powder content in the rubberized asphalt is the percentage of rubber powder mass to asphalt mass; the residual rubber powder content in the rubberized asphalt is the percentage of residual rubber powder mass to the mass of added rubber powder; the swollen rubber powder content in the rubberized asphalt is the percentage of swollen rubber powder mass to the mass of added rubber powder. In step 4, the extraction steps for the remaining rubber powder in the rubber asphalt are as follows: T1. Soak the required filter paper in a clean tetrahydrofuran solution for 1 hour, then dry it in an oven at 105℃±5℃, weigh it and record m0. T2. Heat the rubber asphalt to a molten state and stir it evenly. Place filter paper on the weighing platform of the electronic balance and weigh about 5g of rubber asphalt sample m1. T3. Fold the filter paper to seal the asphalt sample tightly, and then immerse it completely in tetrahydrofuran solution for 12 hours. T4. Assemble the functional assembly device for the powder extraction device. Put 130ml of clean tetrahydrofuran solution into a flat-bottomed single-necked flask and place the soaked sample into the extractor. T5. Set the oil bath temperature to 150℃, turn on the oil bath heating and condenser water circulation functions, and distill to extract the remaining rubber powder particles in the rubber asphalt. Stop the distillation extraction when the filter paper wrapped with the sample turns white or light yellow and the color does not change for 30 minutes. T6. Remove the filter paper and sample after distillation and place them in an oven at 105℃±5℃ to dry. Then weigh them (m). 2; The specific expression of the formula for calculating the residual rubber powder content in rubber asphalt is as shown in formula (1): ； Where: W—residual rubber powder content in rubber asphalt (%); x——Individual rubber powder content in rubber asphalt (%) m0 — Mass of dried filter paper (g); m1——Mass of rubber asphalt and filter paper before extraction (g); m2 — Mass (g) of extracted rubber asphalt and filter paper.

2. The method for detecting the rubber powder content in rubberized asphalt according to claim 1, characterized in that: In step 3, the functional assembly of the adhesive powder extraction device includes, from top to bottom: a cooling section at the top of the device, an extraction section in the middle, and a heating section at the bottom of the device.

3. The method for detecting the rubber powder content in rubberized asphalt according to claim 2, characterized in that: The cooling section consists of a glass spherical condenser tube, with one end connected to the water inlet by a latex hose and the other end connected to the drain tank.

4. The method for detecting the rubber powder content in rubberized asphalt according to claim 3, characterized in that: The number of glass spherical condenser tubes is one or more, and they are used in series.

5. The method for detecting the rubber powder content in rubberized asphalt according to claim 2, characterized in that: The extraction section is a glass extractor, connected to a cooling section at the top and a heating section at the bottom.

6. The method for detecting the rubber powder content in rubberized asphalt according to claim 2, characterized in that: The heating element is a flat-bottomed single-necked flask, which is heated by a constant-temperature oil bath.

Images