A detection method for additive content in vulcanized rubber powder / sbs composite modified asphalt

Abstract

The application discloses a kind of detection methods of additive content in vulcanized rubber powder / SBS composite modified asphalt.The application first utilizes the solubility difference of matrix asphalt, vulcanized rubber powder and SBS modifier in gasoline, separates matrix asphalt first, then ingeniously utilizes the characteristics that ash classification substance remains in vulcanized rubber powder under high-temperature calcination condition and asphalt and SBS modifier almost have no residue, creatively uses ash classification substance in vulcanized rubber powder as marker, thereby realizes the metering and detection of vulcanized rubber powder content in composite modified asphalt, and the content of SBS modifier in composite modified asphalt can be calculated by the amount reduction method.The application has the advantages of convenient operation, strong implementation, high accuracy, good reproducibility, and can realize the effect of "one method double detection", which can detect the addition amount of each component in vulcanized rubber powder / SBS composite modified asphalt, and control the quality of vulcanized rubber powder used.

Description

A method for determining the additive content in vulcanized rubber powder / SBS composite modified asphalt Technical Field

[0001] This invention belongs to the technical field of additive content determination in composite modified asphalt, and specifically relates to a method for detecting the additive content in vulcanized rubber powder / SBS composite modified asphalt. Background Technology

[0002] The production of vulcanized rubber powder from waste tires is an emerging materials science and a promising circular economy approach that integrates environmental protection and resource recycling. It is also the best way to promote a circular economy. Processing waste tires into waste tire rubber powder is a globally recognized method for the harmless and resource-efficient treatment of waste tire rubber. Using waste tire rubber powder as an asphalt modifier in the highway industry is one of the main ways to achieve the resource-efficient and harmless utilization of waste tires. Road-use waste tire rubber powder specifically refers to waste tire rubber powder used in asphalt or asphalt mixtures, generally vulcanized rubber powder.

[0003] In recent years, to improve the performance and stability of modified asphalt, high-grade highways in my country often use rubber powder / SBS composite modified asphalt, prepared by combining vulcanized rubber powder and SBS modifier, for surface paving. The rubber powder content in composite modified asphalt is an important indicator for evaluating its quality and one of the most direct ways to assess the technological advancement. In principle, the more rubber powder a composite modified asphalt utilizes, the better its economic efficiency and the greater the resulting social benefits. Increasingly, design documents specify a lower limit for the rubber powder content in composite modified asphalt, and some existing composite modified asphalts have rubber powder contents significantly lower than normal. The SBS modifier content in composite modified asphalt is crucial for quality control and ensuring pavement durability; however, due to the high price of SBS, insufficient SBS content is often encountered during construction, making the control of the dosage of various additives in the preparation of composite modified asphalt extremely important.

[0004] Typically, there are difficulties in separating additives from asphalt in rubber powder / SBS composite modified asphalt, making it challenging to detect the dosage of each component. This creates blind spots in material usage detection during construction. Developing an effective method for detecting the dosage of additives in vulcanized rubber powder / SBS composite modified asphalt is one of the urgent technical problems that needs to be solved by those skilled in the art. Summary of the Invention

[0005] To address the aforementioned technical problems, this invention provides a method for detecting the amount of additives in vulcanized rubber powder / SBS composite modified asphalt. This method fills the technical difficulty of detecting the dosage of various components in existing composite modified asphalt, and is of great significance for improving engineering quality and promoting technological progress.

[0006] This invention first utilizes the difference in solubility of base asphalt, vulcanized rubber powder, and SBS modifier in gasoline to separate the base asphalt. Then, it cleverly takes advantage of the fact that vulcanized rubber powder still has ash residue under high-temperature calcination conditions, while asphalt and SBS modifier have almost no residue. The ash residue in vulcanized rubber powder is creatively used as a marker, thereby realizing the measurement and detection of the amount of vulcanized rubber powder in composite modified asphalt. The amount of SBS modifier in composite modified asphalt can be calculated by the reduction method.

[0007] A method for detecting the additive content in vulcanized rubber powder / SBS composite modified asphalt mainly includes the following steps:

[0008] (1) Asphalt content testing

[0009] a. Weigh out vulcanized rubber powder / SBS composite modified asphalt, and record the mass as m. Use gasoline as a solvent to fully dissolve the vulcanized rubber powder / SBS composite modified asphalt and filter out the insoluble matter. Wash the insoluble matter repeatedly with gasoline until the gasoline color is clear.

[0010] b. Wash the insoluble matter and dry it at 60-110℃ to constant weight, and record the mass as m1; collect the gasoline solution and dry it to make the gasoline evaporate completely, and record the mass of the solids as m2;

[0011] c. The mass m of the vulcanized rubber powder / SBS composite modified asphalt, the mass m1 of the washed insoluble matter, and the mass m2 of the solids must meet the following requirements. Take after satisfying the condition The mass of asphalt in the vulcanized rubber powder / SBS composite modified asphalt, denoted as mass m, is denoted as m. a Then the proportion of asphalt is

[0012] d. When the mass m of the vulcanized rubber powder / SBS composite modified asphalt, the mass m1 of the washed insoluble matter, and the mass m2 of the solids do not satisfy the following conditions... Repeat steps a and b until the condition is met, and the mass and proportion of asphalt in the vulcanized rubber powder / SBS composite modified asphalt can be calculated.

[0013] (2) Detection of vulcanized rubber powder content

[0014] a. Prepare several high-temperature resistant crucibles, clean and dry them to constant weight, and accurately weigh each crucible using an analytical balance.

[0015] b. Weigh several portions of vulcanized rubber powder that are the same as the vulcanized rubber powder added to the vulcanized rubber powder / SBS composite modified asphalt to be tested, according to the quartering method. Each portion weighs 4-6g. Weigh each portion of vulcanized rubber powder accurately using an analytical balance.

[0016] c. After heating the vulcanized rubber powder / SBS composite modified asphalt sample to be tested to a fluid state, pour it into a pre-weighed crucible and calcine it in a muffle furnace at 800-1000℃ until constant weight. Accurately weigh each crucible and its residue after calcination using an analytical balance, calculate the mass of each residue, divide it by the corresponding mass of the vulcanized rubber powder / SBS composite modified asphalt sample, calculate the residue rate of each sample, and take the average value as the residue rate J of the batch of vulcanized rubber powder / SBS composite modified asphalt samples.

[0017] d. Place the vulcanized rubber powder samples into the crucibles in sequence and calcine them to constant weight at the same temperature as in step c. Use an analytical balance to accurately weigh the mass of each crucible and its residue after calcination, calculate the mass of the residue of each vulcanized rubber powder sample, divide it by the corresponding mass of the vulcanized rubber powder sample, calculate the residual rate of each vulcanized rubber powder, and take the average value as the residual rate B of the batch of vulcanized rubber powder samples.

[0018] e. Therefore, the proportion of vulcanized rubber powder in the total mass of the vulcanized rubber powder / SBS composite modified asphalt sample to be tested can be calculated as J / B.

[0019] (3) SBS content calculation

[0020] Subtract the percentage of asphalt in the vulcanized rubber powder / SBS composite modified asphalt obtained in step (1) from 100%, and then subtract the percentage of vulcanized rubber powder in the vulcanized rubber powder / SBS composite modified asphalt obtained in step (2) to obtain the addition ratio of SBS modifier.

[0021] The method for detecting the additive content in vulcanized rubber powder / SBS composite modified asphalt is applicable to the detection of additive content in vulcanized rubber powder / SBS composite modified asphalt prepared from SBS, vulcanized rubber powder and base petroleum asphalt.

[0022] By employing the above technical solution, the beneficial effects of the present invention are as follows:

[0023] (1) It can realize the detection of the content of each component in the rubber powder / SBS composite modified asphalt.

[0024] This invention first utilizes the principle that asphalt is readily soluble in gasoline, while the additives used are insoluble in gasoline, to separate the asphalt and additives and measure their masses. SBS modifier itself is insoluble in gasoline, while road-grade vulcanized rubber powder is formed by the breaking of carbon-carbon double bonds in natural rubber and the insertion of S atoms, causing cross-linking of the polymer bonds and forming a three-dimensional polymer structure. Therefore, it only swells in gasoline and hardly dissolves.

[0025] Ash content is a chemical technical indicator in my country's road waste tire rubber powder specifications. It is one of the inherent properties of vulcanized rubber powder itself. In this invention, ash content is used as an important criterion to distinguish vulcanized rubber powder from base asphalt and SBS modifier. Road vulcanized rubber powder generally exhibits weight loss at around 200℃, and primary pyrolysis is basically completed at around 500℃. At higher temperatures, only ash residue remains. Asphalt is a complex blackish-brown mixture composed of hydrocarbons of different molecular weights and their non-metallic derivatives, mainly composed of four types of substances: saturated components, aromatic components, asphaltenes, and resins. SBS modifier and base asphalt can be completely burned off in a muffle furnace at 500℃, leaving almost no residue.

[0026] This invention ingeniously utilizes the characteristic that vulcanized rubber powder still retains ash residue under high-temperature calcination conditions, while asphalt and SBS modifier leave almost no residue. It creatively uses the ash residue in vulcanized rubber powder as a marker, thereby enabling the measurement and detection of the rubber powder content in rubber powder / SBS composite modified asphalt. The proportions of base asphalt, vulcanized rubber powder, and SBS modifier in the composite modified asphalt can be determined sequentially using a reduction method. This method is convenient to operate, highly implementable, and suitable for supplementing current specifications.

[0027] (2) High accuracy and good reproducibility

[0028] This method first utilizes the difference in solubility of asphalt, vulcanized rubber powder, and SBS modifier in gasoline to separate the asphalt. The process is simple to operate, its principle is clear, and its error is small.

[0029] Publicly available patents report methods for determining the amount of rubber powder by dissolving rubber asphalt with reagents. This invention eliminates the need for reagents; high-temperature calcination is sufficient to calculate the proportion and range of vulcanized rubber powder in a batch of composite modified asphalt. It offers high accuracy, eliminates deviations caused by operational methods, and exhibits good reproducibility.

[0030] (3) One method for dual detection, intuitive and efficient

[0031] Current Chinese standards and specifications require specific ash content parameters for rubber powder, which is also one of the key indicators for controlling the quality of the rubber powder itself. The testing of the calcination residue rate of vulcanized rubber powder in the operation method of this invention shows a high degree of similarity and a significant positive correlation with the detection of the ash content of vulcanized rubber powder. This method can also control the quality of vulcanized rubber powder, achieving a "dual detection" effect. It can both detect the amount of vulcanized rubber powder in vulcanized rubber powder / SBS composite modified asphalt and control the quality of the rubber powder used, thus achieving two benefits in one step.

[0032] This invention has the advantages of convenient operation, strong implementation, high accuracy, and good reproducibility. It can also achieve the effect of "one method for two inspections", which can both detect the amount of each component added in vulcanized rubber powder / SBS composite modified asphalt and control the quality of the vulcanized rubber powder used, thus achieving two benefits in one.

[0033] The present invention will be further described in detail below with reference to embodiments. These embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Those skilled in the art can make various modifications or alterations to the present invention and apply the general principles described herein to other embodiments without creative effort. These equivalent forms also fall within the scope defined by the appended claims. Detailed Implementation

[0034] The present invention will be further described below with reference to embodiments:

[0035] Example 1

[0036] (1) Asphalt content testing

[0037] Take 100.4638g of vulcanized rubber powder / SBS composite modified asphalt, use gasoline as a solvent to fully dissolve the vulcanized rubber powder / SBS composite modified asphalt and filter out the insoluble matter, and repeatedly wash the insoluble matter with gasoline until the gasoline color is clear;

[0038] The washed insoluble matter was dried at 100℃ to constant weight, and the mass was 22.0285g; the gasoline solution was collected and dried to allow the gasoline to evaporate completely, and the mass of the solids was recorded as 77.5241g.

[0039] (mass of vulcanized rubber powder / SBS composite modified asphalt - mass of washed insoluble matter - mass of solids) / mass of vulcanized rubber powder / SBS composite modified asphalt * 100% = 0.9070% < 2%. The mass of matrix asphalt in vulcanized rubber powder / SBS composite modified asphalt is 77.9797g, and the proportion of matrix asphalt in composite modified asphalt is 77.62%.

[0040] (2) Detection of vulcanized rubber powder content

[0041] Prepare 6 high-temperature resistant crucibles, clean and dry them to constant weight, and accurately weigh each crucible using an analytical balance.

[0042] Three portions of vulcanized rubber powder were weighed evenly using the quartering method, and the mass of each portion of vulcanized rubber powder was accurately weighed using an analytical balance.

[0043] After heating the vulcanized rubber powder / SBS composite modified asphalt sample to a fluid state, pour it into three pre-weighed crucibles, each containing approximately 50g of material. Then, calcine the three crucibles containing the vulcanized rubber powder / SBS composite modified asphalt sample in a muffle furnace at 950℃ until constant weight. Accurately weigh each crucible and its contents after calcination using an analytical balance. Calculate the mass of the residual material in each composite modified asphalt sample. Divide this mass by the mass of the vulcanized rubber powder / SBS composite modified asphalt sample to calculate the residual rate of each composite modified asphalt sample. The average value of this average value is recorded as the residual rate of the batch of vulcanized rubber powder / SBS composite modified asphalt samples.

[0044] Three samples of vulcanized rubber powder were placed into three crucibles in sequence and calcined in a muffle furnace at 950℃ until constant weight. The mass of each crucible and its residue after calcination was accurately weighed using an analytical balance. The mass of the residue of each vulcanized rubber powder was calculated and divided by the mass of each vulcanized rubber powder sample to calculate the residual rate of each vulcanized rubber powder. The average value was recorded as the residual rate of the batch of vulcanized rubber powder samples.

[0045] Table 1. Relevant data on residual rate of vulcanized rubber powder.

[0046]

[0047]

[0048] Table 2. Relevant data on residual rate of vulcanized rubber powder / SBS composite modified asphalt.

[0049]

[0050] Based on the data in Tables 1 and 2, the mass of vulcanized rubber powder in the three samples of vulcanized rubber powder / SBS composite modified asphalt can be calculated to be 10.1339 g, 10.7701 g, and 10.3349 g, respectively; the proportion of rubber powder in the composite modified asphalt is 20.34%, 20.43%, and 20.48%, respectively. The average proportion of vulcanized rubber powder in the composite modified asphalt of this batch of vulcanized rubber powder / SBS composite modified asphalt samples is 20.42%.

[0051] (3) SBS content calculation

[0052] The proportion of SBS modifier added to vulcanized rubber powder / SBS composite modified asphalt is 100% - 77.62% - 20.42% = 1.96%.

Claims

1. A method for detecting the additive content in vulcanized rubber powder / SBS composite modified asphalt, characterized in that, The detection method includes the following steps: (1) Asphalt content detection a. Weigh the vulcanized rubber powder / SBS composite modified asphalt, and record the mass as m. Use gasoline as a solvent to fully dissolve the vulcanized rubber powder / SBS composite modified asphalt and filter out the insoluble matter. Wash the insoluble matter repeatedly with gasoline until the gasoline color is clear; b. Dry the washed insoluble matter at 60-110℃ to constant weight, and record the mass as m1; collect the gasoline solution and dry it to make the gasoline evaporate completely, and record the solid matter mass as m2; c. The mass m of the vulcanized rubber powder / SBS composite modified asphalt, the mass m1 of the washed insoluble matter, and the solid matter mass m2 must meet the following requirements. Take it after the condition is satisfied. The mass of asphalt in the vulcanized rubber powder / SBS composite modified asphalt, denoted as mass m, is denoted as m. a Then the proportion of asphalt is d. When the mass m of the vulcanized rubber powder / SBS composite modified asphalt, the mass m1 of the washed insoluble matter, and the mass m2 of the solids do not satisfy the following conditions: Repeat steps a and b until satisfied, from which the mass and proportion of asphalt in vulcanized rubber powder / SBS composite modified asphalt can be calculated; (2) Vulcanized rubber powder content detection a. Prepare several high-temperature resistant crucibles, clean and dry them to constant weight, and accurately weigh each crucible using an analytical balance; b. Weigh several vulcanized rubber powder samples that are the same as the vulcanized rubber powder added to the vulcanized rubber powder / SBS composite modified asphalt to be tested according to the quartering method, each sample weighing 4-6g, and accurately weigh each sample using an analytical balance; c. Heat the vulcanized rubber powder / SBS composite modified asphalt sample to be tested to a flowing state and pour it into the weighed crucible, calcine it in a muffle furnace at 800-1000℃ to constant weight, accurately weigh each crucible and its residue after calcination using an analytical balance, calculate the mass of each residue, divide it by the mass of the corresponding vulcanized rubber powder / SBS composite modified asphalt sample, calculate the residue rate of each sample, and take its The average value is recorded as the residual rate J of this batch of vulcanized rubber powder / SBS composite modified asphalt samples; d. Put the vulcanized rubber powder samples into the crucible in sequence and calcine them to constant weight at the same temperature as in step c. Use an analytical balance to accurately weigh the mass of each crucible and its residue after calcination, calculate the mass of the residue of each vulcanized rubber powder sample, divide it by the mass of the corresponding vulcanized rubber powder sample, calculate the residual rate of each vulcanized rubber powder, and take the average value as the residual rate B of this batch of vulcanized rubber powder samples; e. From this, the proportion of vulcanized rubber powder in the total mass of the vulcanized rubber powder / SBS composite modified asphalt sample to be tested can be calculated as J / B×100%; (3) SBS content calculation: 100% minus the proportion of asphalt in vulcanized rubber powder / SBS composite modified asphalt measured in step (1), and then minus the proportion of vulcanized rubber powder in vulcanized rubber powder / SBS composite modified asphalt measured in step (2) to obtain the addition ratio of SBS modifier.

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