A method for detecting storage stability of granulated asphalt mixture additives

Abstract

The present invention discloses a storage stability detection method for a granulated asphalt mixture additive, comprising the following steps: (1) taking a sample to be tested of a preset mass and spreading it into a container; (2) determining a pressure load according to a stacking height and a particle packing density of simulated storage conditions; setting a temperature load according to an upper limit of a storage temperature range, and applying corresponding pressure and temperature loads to the sample to be tested; continuing the pressure load and temperature load conditions for a preset time to simulate the influence of the storage period on the dispersion performance of the granulated asphalt mixture additive; (3) determining its agglomeration rate after the simulation, and judging the storage stability of the granulated asphalt mixture additive to be tested according to the principle that the higher the agglomeration rate, the worse the storage stability of the granulated asphalt mixture additive to be tested. The present method can accurately, quickly and objectively judge the storage stability of the granulated asphalt mixture additive.

Description

Technical Field

[0001] The invention belongs to the field of road engineering material detection, and more specifically, relates to a storage stability detection method for a granulated asphalt mixture additive. Background Art

[0002] The wet method of preparing modified asphalt mixtures first requires the preparation of modified asphalt, which is a complex process and requires specific equipment and storage stability. However, direct-injection granulated asphalt mixture additives are easy to add and do not require special equipment. They have currently occupied a certain market. Granulated asphalt mixture additives usually have a storage period from the completion of production to the delivery to the construction site. This is because they need to wait until there is an order before they are delivered to the construction site. However, when the granulated asphalt mixture additives are stored and transported in the warehouse, the pressure generated by the ambient temperature and stacking height will cause the granulated asphalt mixture additives to clump. If the agglomeration rate is too high, it is easy to make it difficult for the granulated asphalt mixture additives to be evenly dispersed in the asphalt mixture and become ineffective.

[0003] It is very important to test whether the prepared granulated asphalt mixture additive meets the storage conditions, whether it can maintain good dispersion performance during the storage period, and avoid agglomeration during use, in order to evaluate the quality performance of the granulated asphalt mixture.

[0004] However, there is currently no suitable testing method for the storage stability of granulated asphalt mixture additives. Therefore, how to accurately, quickly and objectively determine the storage stability period of granulated asphalt mixture additives has become an urgent problem to be solved. Summary of the invention

[0005] In view of the above defects or improvement needs of the prior art, the present invention provides a method for detecting the storage stability of a granulated asphalt mixture additive, the purpose of which is to continuously apply extreme storage conditions of a granulated asphalt mixture modifier, and evaluate the storage stability of the granulated asphalt mixture additive by agglomeration rate, so as to quickly, objectively and accurately evaluate the storage stability of the granulated asphalt mixture additive, thereby solving the technical problem of the lack of a method for detecting the storage stability of a granulated asphalt mixture additive in the prior art.

[0006] To achieve the above object, according to one aspect of the present invention, a method for detecting storage stability of a granulated asphalt mixture additive is provided, characterized in that it comprises the following steps:

[0007] (1) Taking a predetermined mass of the granulated asphalt mixture additive to be tested, spreading it into a predetermined container with a predetermined area as the sample to be tested;

[0008] (2) Determine the pressure load according to the stacking height and particle packing density of the simulated storage conditions, and apply the corresponding pressure load to the sample to be tested obtained in step (1); set the temperature load according to the upper limit of the storage temperature range, and apply the corresponding temperature load to the sample to be tested obtained in step (1); continue the pressure load and temperature load conditions for a preset time;

[0009] (3) performing an agglomeration rate test on the sample to be tested that has undergone the storage condition simulation of step (2), and judging the storage stability of the granulated asphalt mixture additive to be tested based on the agglomeration rate test result and the principle that the higher the agglomeration rate, the worse the storage stability of the granulated asphalt mixture additive to be tested.

[0010] Preferably, in the method for detecting storage stability of the granulated asphalt mixture additive, the pressure load σ is determined in step (2) and is specifically calculated according to the following formula:

[0011] σ=ρ·g·h

[0012] Where ρ is the bulk density, g is the acceleration due to gravity, and h is the stacking height.

[0013] Preferably, in the method for testing the storage stability of granulated asphalt mixture additives, the temperature load in step (2) is between 50-70°C.

[0014] Preferably, in the storage stability testing method for granulated asphalt mixture additives, the preset time length in step (2) is greater than or equal to 1 hour, preferably between 48-72 hours.

[0015] Preferably, in the storage stability detection method of the granulated asphalt mixture additive, the specific judgment principle of step (3) is as follows: when the agglomeration rate of the sample to be tested exceeds a preset agglomeration rate threshold, it is judged that the stability of the sample to be tested is poor; otherwise, it is judged that the stability of the sample to be tested is good.

[0016] Preferably, in the storage stability detection method of the granulated asphalt mixture additive, the agglomeration rate threshold value is between 5-10%.

[0017] Preferably, the agglomeration rate threshold value of the granulated asphalt mixture additive storage stability detection method is 5%.

[0018] Preferably, in the method for detecting storage stability of granulated asphalt mixture additives, the preset time duration in step (2) is set according to the following principles:

[0019] A reference sample with good storage stability is stored under a preset pressure load and temperature load for a period of time so that the agglomeration rate of the reference sample with good storage stability is within a preset agglomeration rate range, and the period is determined as the preset period; the lower limit of the preset agglomeration rate range is preferably 0.5 times the agglomeration rate threshold, and the upper limit is preferably 2 times the agglomeration rate threshold.

[0020] Preferably, the storage stability detection method of the granulated asphalt mixture additive, wherein the agglomeration rate is the mass M of the agglomerated sample 1i Specifically, the standard sieve can be used for screening until the residual mass of the granulated asphalt mixture additive that does not pass the standard sieve is stable, and the residual mass of the granulated asphalt mixture additive at this time is determined to be the mass of the agglomerated sample M 1i .

[0021] Preferably, the method for testing the storage stability of the granulated asphalt mixture additive uses a standard sieve slightly larger than the maximum size specification of the granulated asphalt mixture additive for screening.

[0022] In general, the above technical solution conceived by the present invention is compared with the prior art, because the present invention provides a storage stability detection method for granulated asphalt mixture additives, which can achieve the following beneficial effects:

[0023] The storage stability of the sample to be tested is determined by pressurizing and storing the simulated granulated asphalt mixture additive under extreme storage temperature conditions, wherein the pressure load is determined according to the stacking height and particle packing density of the storage conditions, the temperature load is set according to the upper limit of the simulated storage temperature range, and the sample is stored for a preset time under the simulated conditions. The agglomeration rate is determined to evaluate the storage stability of the granulated asphalt mixture additive. The detection speed is fast, and the storage stability of the granulated asphalt mixture additive can be objectively and accurately evaluated, and the repeatability is good. The method can accurately, quickly and objectively judge the storage stability of the granulated asphalt mixture additive, which has important guiding significance for the actual use of the granulated asphalt mixture additive. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is a photo of a simulated storage device used to test the storage stability of samples;

[0025] Figure 2 Schematic diagram of the agglomeration effect of the star-shaped SBS particles of the asphalt modifier of Examples 1-3;

[0026] in Figure 2 From left to right in the figure are schematic diagrams of the agglomeration effects of Example 1, Example 2, and Example 3;

[0027] Figure 3This is a schematic diagram of the agglomeration effect of the star-shaped SBS particles of the asphalt modifier in Comparative Examples 1-3;

[0028] in Figure 3 From left to right in the figure are the agglomeration effects of Comparative Example 1, Comparative Example 2, and Comparative Example 3;

[0029] Figure 4 This is a schematic diagram of the agglomeration effect of rubber powder and asphalt premixed particles in Example 4-6;

[0030] in Figure 4 From left to right in the figure are schematic diagrams of the agglomeration effects of Example 4, Example 5, and Example 6;

[0031] Figure 5 This is a schematic diagram of the agglomeration effect of rubber powder and asphalt premixed particles in comparative examples 4-6;

[0032] in Figure 5 From left to right in the figure are the agglomeration effects of Comparative Example 4, Comparative Example 5, and Comparative Example 6;

[0033] Figure 6 Schematic diagram of the agglomeration effect of rock asphalt and asphalt premixed particles in Example 7-9;

[0034] in Figure 6 From left to right in the figure are schematic diagrams of the agglomeration effects of Example 7, Example 8, and Example 9;

[0035] Figure 7 This is a schematic diagram of the agglomeration effect of rock asphalt and asphalt premixed particles in comparative examples 7-9;

[0036] in Figure 7 From left to right in the figure are the agglomeration effects of Comparative Example 7, Comparative Example 8, and Comparative Example 9. DETAILED DESCRIPTION

[0037] In order to make the purpose, technical scheme and advantages of the present invention clearer, the present invention is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0038] The storage stability of granulated asphalt mixture additives is a key indicator among its performance indicators, which can be characterized by the agglomeration rate AR. The lower the agglomeration rate during storage, the better the storage stability of the granulated asphalt mixture additives. However, during storage, due to the influence of storage conditions such as storage temperature, storage time and pressure generated by stacking height, the granulated asphalt mixture additives agglomerate, affecting its performance, and even making it impossible to use or directly use it due to a significant increase in the agglomeration rate. Therefore, it is very important to determine the storage stability of granulated asphalt mixture additives, especially the stability under extreme high temperature conditions. However, the prior art lacks a method for detecting the storage stability of granulated asphalt mixture additives.

[0039] We experimentally measured the agglomeration rate of granulated asphalt mixture additives in the storage and transportation process (temperature, pressure and time) of simulated granulated asphalt mixture additives at a certain temperature and found that the stability under a specific storage condition determined by simulation test can reflect the stability of the granulated asphalt mixture additives after being stored under the storage condition for a period of time; the experiment shows that by simulating the storage temperature and storage pressure, the storage process can be effectively simulated to determine the storage stability of the granulated asphalt mixture additive, especially at the extreme storage temperature, the results of the simulation measurement can better reflect the excellent stability of the additive.

[0040] The specific storage condition simulation process includes measuring the agglomeration rate under the conditions of applying pressure and temperature load to simulate the extreme storage temperature to accelerate agglomeration, so as to judge the storage stability under the measured conditions or predict the actual storage conditions; that is, by measuring the agglomeration rate of the granulated asphalt mixture additive under the conditions of preset pressure, preset temperature and preset storage time, if the result of its agglomeration rate exceeds the preset threshold, it indicates that the storage stability of the granulated asphalt mixture additive is poor after being stored for the preset time under the measured conditions, otherwise, its storage stability is good. This method can accurately, quickly and objectively judge the storage stability of the granulated asphalt mixture additive under simulated storage conditions.

[0041] The present invention provides a method for detecting storage stability of a granulated asphalt mixture additive, which comprises the following steps:

[0042] (1) Take a preset mass of the granulated asphalt mixture additive to be tested and spread it into a container with a preset area as the sample to be tested; specifically:

[0043] Take the granulated asphalt mixture additive to be tested, and record the mass M0 of the granulated asphalt mixture additive; spread the granulated asphalt mixture additive to be tested evenly in a container.

[0044] The granulated asphalt mixture additive is uniform in size, with a particle size of 1 mm to 10 mm, preferably 3 mm to 6 mm.

[0045] (2) Determining a pressure load according to the stacking height and the particle packing density under simulated storage conditions and determining a temperature load according to the temperature under simulated extreme temperature conditions, and applying corresponding pressure loads and temperature loads to the test sample obtained in step (1); continuing the pressure load and temperature load conditions for a preset period of time to simulate the effect of the storage period on the dispersion performance of the granulated asphalt mixture additive;

[0046] The pressure load is estimated to obtain the appropriate pressure σ according to the actual storage and stacking height of the granulated asphalt mixture additive and its stacking density, and is specifically calculated according to the following formula:

[0047] σ=ρ·g·h

[0048] Where ρ is the bulk density, g is the acceleration of gravity, which is usually 10N / kg, and h is the stacking height of the granulated asphalt mixture additive.

[0049] For example, assuming that the granulated asphalt mixture additive is stacked at a height of 1m and a bulk density of 0.6g / cm 3 According to the formula, the pressure on the bottom of the granulated asphalt mixture additive is about 6kPa, that is, the granulated asphalt mixture additive should be pressurized to 6kPa when testing stability.

[0050] The temperature load is set according to the following principles:

[0051] The temperature load is set according to the upper limit of the simulated storage temperature range of the sample to be tested, and the storage temperature is preferably set between 50-70°C;

[0052] During storage and transportation, the granulated asphalt mixture additive may be in an ambient temperature of -20°C to 70°C. 70°C can be taken as the ultimate high temperature storage temperature of the granulated asphalt mixture additive. Preferably, the storage temperature is between 50-70°C, that is, the simulation measurement under the conditions of 50-70°C extreme storage temperature can reflect the impact of the actual storage temperature and long-term pressure on the stability of the granulated asphalt mixture additive, making the measurement result more reliable, and also conducive to quickly and objectively judging the excellent storage stability of the granulated asphalt mixture additive. The more preferred storage temperature is 70°C.

[0053] The preset duration is greater than or equal to 1 hour, and is preferably set according to the following principles:

[0054] A reference sample with good storage stability is stored under a preset pressure load and temperature load for a period of time so that the agglomeration rate of the reference sample with good storage stability is within a preset agglomeration rate range, and the period is determined as the preset period; the lower limit of the preset agglomeration rate range is preferably 0.5 times the agglomeration rate threshold, and the upper limit is preferably 2 times the agglomeration rate threshold.

[0055] The reference sample with good storage stability is a granulated asphalt mixture modifier whose degree of hardening after long-term storage does not affect its use, such as a commercial granulated asphalt modifier, and star-shaped SBS particles can be selected.

[0056] By taking the agglomeration rate of the reference sample with good storage stability stored under the set pressure load and temperature load conditions as a reference, the agglomeration rate can be controlled within the range suitable for the experimental conditions and with high resolution, so as to better observe the stability of the granulated asphalt mixture additive. If the storage time is too short, the base asphalt of the granulated asphalt mixture additive has not yet shown obvious agglomeration phenomenon, and it is difficult to distinguish the stability of different granulated asphalt mixture modifiers; if the storage time is too long and the test conditions are too harsh, it may even lead to the inability to maintain the granulated form, and the stability of the granulated asphalt mixture modifier cannot be well evaluated.

[0057] Experiments show that under given pressure and temperature conditions, when the storage time is extended to 24 hours, the clumping rate increases by 1-3 times. When the storage time exceeds 24 hours and ranges from 72 hours, the increase in the clumping rate decreases. Therefore, the preset storage time is generally set between 24 and 72 hours. Combined with the preset clumping rate range requirements, an appropriate storage time, i.e., the preset time, is set.

[0058] For example, under the temperature load condition of 70°C, the threshold value for judging the storage stability of granulated asphalt mixture additives is 5%, and the preset agglomeration rate range is set at 2.5% to 10%. Under this test condition, reference samples with good storage stability usually need to be stored for 48-72 hours so that their agglomeration rate can reach the preset agglomeration rate range of 2.5% to 10%. In this case, 48-72 hours is selected as the preset storage duration.

[0059] (3) performing an agglomeration rate test on the sample to be tested that has undergone the storage condition simulation of step (2), and judging the storage stability of the granulated asphalt mixture additive to be tested based on the agglomeration rate test result and the principle that the higher the agglomeration rate, the worse the storage stability of the granulated asphalt mixture additive to be tested, wherein the specific judging principle is as follows: after being stored for a preset period of time under the measuring conditions, when the agglomeration rate of the sample to be tested exceeds a preset agglomeration rate threshold, it is judged that the stability of the sample to be tested is poor; otherwise, it is judged that the stability of the sample to be tested is good;

[0060] The agglomeration rate threshold is between 5-10%. If the agglomeration rate threshold is 10%, that is, the agglomeration rate measurement result exceeds 10%, indicating that the storage stability of the granulated asphalt mixture additive after being stored for a preset period of time under simulated conditions is poor, otherwise, the storage stability is good; preferably, the agglomeration rate threshold is 5%, that is, the agglomeration rate measurement result exceeds 5%, indicating that the stability of the sample after being stored for a preset period of time under the simulated conditions is poor, otherwise, the storage stability of the sample is good.

[0061] The agglomeration rate is the mass M of the agglomerated sample. 1i Specifically, the standard sieve can be used for screening until the residual mass of the granulated asphalt mixture additive that does not pass the standard sieve is stable, and the residual mass of the granulated asphalt mixture additive at this time is determined to be the mass of the agglomerated sample M 1i For example, if the standard sieve is used for screening until the mass of the granulated asphalt mixture additive passing through the standard sieve within 1 minute is less than 0.1% of the residual mass in the standard sieve, the residual mass of the granulated asphalt mixture additive is considered to be stable, and the screening is stopped and the residual mass M of the granulated asphalt mixture additive on the sieve is recorded. 1i As the mass of the agglomerated sample; and calculate the agglomeration rate AR ij , calculated according to the following formula:

[0062]

[0063] In the above formula, the aggregation rate AR ij At temperature T i Storage conditions j M0 is the mass of the granulated asphalt mixture additive to be tested.

[0064] It is preferred to use a standard sieve slightly larger than the maximum size specification of the granulated asphalt mixture additive for screening; for example, the maximum particle size of the granulated asphalt mixture additive is 4 mm, preferably a standard sieve of 4.75 mm.

[0065] The following are examples:

[0066] The following examples simulate the stacking height of granulated asphalt mixed with additives at 1m and a bulk density of 0.6g / cm 3 , in the case of summer storage.

[0067] Example 1 Stability test of asphalt modifier star-shaped SBS particles

[0068] The granulated asphalt mixture additive is star-shaped SBS particles commonly used as asphalt modifiers in road engineering, with a maximum nominal particle size of 4mm. The test method is as follows:

[0069] (1) Take a preset mass of the granulated asphalt mixture additive to be tested and spread it into a container with a preset area as the sample to be tested; the details are as follows:

[0070] An iron cylinder with openings at both ends is used as a container. The cylinder has a diameter of 101.6 mm and a height of 87 mm. The iron cylinder with openings at both ends is placed on a stainless steel plate. Both are placed on an electronic scale and reset to zero. Then, the granulated asphalt mixture additive is spread over the iron cylinder and the mass M0 of the granulated asphalt mixture additive is recorded.

[0071] (2) Determining a pressure load according to the stacking height and the particle packing density under simulated storage conditions and determining a temperature load according to the temperature under simulated extreme temperature conditions, and applying corresponding pressure loads and temperature loads to the test sample obtained in step (1); continuing the pressure load and temperature load conditions for a preset period of time to simulate the effect of the storage period on the dispersion performance of the granulated asphalt mixture additive;

[0072] Determine the pressure load: Bulk density 0.6g / cm 3 , the stacking height of granular asphalt mixture additive is 1m, the pressure load is: σ=ρ·g·h, σ is about 6kPa; according to the inner diameter of the container, a 5kg weight is used to provide the pressure load.

[0073] Determine the temperature load: 70°C is taken as the storage limit temperature of the granular asphalt mixture additive.

[0074] Determine the preset storage time: Select star-shaped SBS particles as a reference sample with good storage stability for reference, select 5% as the agglomeration rate threshold, and select the preset agglomeration rate range from 2.5% to 10%. Under the storage conditions of 6kPa and 70°C, when stored for 24h to 48h, the agglomeration rate of petroleum asphalt particles is within the agglomeration rate range, and the preset time is selected to be 24h. Star-shaped SBS particles were purchased from Sinopec Baling Petrochemical Company, model SBS1201E.

[0075] A 5kg weight is placed on the surface of the granular additive to simulate the pressure on the granular asphalt mixed additive. Figure 1 As shown, finally placed together in an oven at 70°C for 24 hours, the star-shaped SBS particles were taken out and sieved through a standard sieve with a mesh size of 4.75 mm until the mass passing through the mesh within 1 minute was less than 0.1% of the residue on the sieve. The residue on the sieve was weighed as M1. Then the ratio of M1 to M0 was defined as the agglomeration rate AR of the granulated asphalt mixture additive.

[0076] (3) Conducting an agglomeration rate test on the sample to be tested that has undergone the storage condition simulation of step (2), and judging the storage stability of the granulated asphalt mixture additive to be tested based on the agglomeration rate test result and the principle that the higher the agglomeration rate, the worse the storage stability of the granulated asphalt mixture additive to be tested. The specific judgment principle is as follows: after being stored for a preset period of time under the measurement conditions, when the agglomeration rate of the sample to be tested exceeds a preset agglomeration rate threshold, it is judged that the stability of the sample to be tested is poor; otherwise, it is judged that the stability of the sample to be tested is good; the agglomeration rate threshold is selected as 5%.

[0077] Example 2

[0078] The granulated asphalt mixture additive used is the same as in Example 1, the storage time is 48 hours, and the others are the same as in Example 1.

[0079] Example 3

[0080] The granulated asphalt mixture additive used is the same as in Example 1, the storage time is 72 hours, and the others are the same as in Example 1.

[0081] Comparative Example 1

[0082] The granulated asphalt mixture additive used is the same as in Example 1, the storage temperature is 25° C., the storage time is 24 h, and the rest is the same as in Example 1.

[0083] Comparative Example 2

[0084] The granulated asphalt mixture additive used is the same as in Example 1, the storage temperature is 25° C., the storage time is 48 h, and the rest is the same as in Example 1.

[0085] Comparative Example 3

[0086] The granulated asphalt mixture additive used is the same as in Example 1, the storage temperature is 25° C., the storage time is 72 h, and the others are the same as in Example 1.

[0087] The agglomeration rate determination results of Examples 1-3 and Comparative Examples 1-3 are shown in Table 1, and the agglomeration effect is shown in Appendix Figure 2 , Attachment Figure 3 , including Figure 2 , from left to right, respectively, are schematic diagrams of the agglomeration effects of Example 1, Example 2, and Example 3; Figure 3 From left to right in the figure are the agglomeration effects of Comparative Example 1, Comparative Example 2 and Comparative Example 3.

[0088] Table 1 Determination results of agglomeration rate of asphalt modifier star-shaped SBS particles

[0089]

[0090] The results in Table 1 show that the agglomeration rate of SBS granular additives is less than 5% when stored at room temperature 25°C for 24-72 hours. Figure 3 It can be seen that there is almost no clumping after storage at room temperature for 72 hours, indicating that the SBS granular additive has good storage stability when stacked at a height of 1m at room temperature.

[0091] When stacked at a height of 1m and stored at 70°C for 72h, the SBS granular additive was also found to be at 5-6%. As can be seen from the table, the SBS granular additive has good stability when stored at 70°C for 3 consecutive days, and there will be no storage stability problems. Compared with storage at room temperature, the high-temperature storage test results show that the SBS granular additive has good stability when stored under high temperature conditions.

[0092] Example 4

[0093] The granulated asphalt mixture additive is a premix of rubber powder and asphalt in a ratio of 1:1, and is granulated by an extruder and coated with an anti-sticking agent (slaked lime). The coating thickness is about 20 μm, the maximum nominal particle size is 5 mm, the storage temperature is 70° C., the storage time is 24 h, and the rest is the same as Example 1.

[0094] Example 5

[0095] The granulated asphalt mixture additive used is the same as in Example 4, the storage temperature is 70° C., the storage time is 48 h, and the rest is the same as in Example 1.

[0096] Example 6

[0097] The granulated asphalt mixture additive used is the same as in Example 4, the storage temperature is 70° C., the storage time is 72 h, and the rest is the same as in Example 1.

[0098] Comparative Example 4

[0099] The granulated asphalt mixture additive used is the same as in Example 4, the storage temperature is 25° C., the storage time is 24 h, and the rest is the same as in Example 1.

[0100] Comparative Example 5

[0101] The granulated asphalt mixture additive used is the same as in Example 4, the storage temperature is 25° C., the storage time is 48 h, and the rest is the same as in Example 1.

[0102] Comparative Example 6

[0103] The granulated asphalt mixture additive used is the same as in Example 4, the storage temperature is 25° C., the storage time is 72 h, and the rest is the same as in Example 1.

[0104] The agglomeration rate determination results of Examples 4-6 and Comparative Examples 4-6 are shown in Table 2, and the agglomeration effect is shown in Appendix Figure 4 , Attachment Figure 5 , including Figure 4Schematic diagram of the agglomeration effect of Example 4, Example 5, and Example 6 from left to right; Figure 5 From left to right in the figure are the agglomeration effects of Comparative Example 4, Comparative Example 5 and Comparative Example 6.

[0105] Table 2 Results of the determination of the agglomeration rate of rubber powder and asphalt premixed powder particles

[0106]

[0107] The results in Table 2 show that when the rubber powder and asphalt premixed powder particles are stored at room temperature at 25°C, the agglomeration rate of the granulated additive is less than 5% within 72 hours of storage at room temperature. Figure 5 It can be seen that it is almost not clumped after being stored at room temperature for 72 hours, indicating that the granular additive has good storage stability when the stacking height is 1m at room temperature. When the stacking height is 1m and the granular additive is stored continuously at 70℃ for 48 hours, the clumping rate of the granular additive is within 5%. It can be seen from the table that the granular additive has good stability when stored at 70℃ for 2 days, and has good storage stability when stored for 3 days.

[0108] Example 7

[0109] The granulated asphalt mixture additive is pre-mixed with rock asphalt and asphalt in a ratio of 19:1, and is granulated by an extruder and coated with an anti-sticking agent (slaked lime). The coating thickness is about 10 μm, the maximum nominal particle size is 5 mm, the storage temperature is 70° C., the storage time is 24 h, and the rest is the same as Example 1.

[0110] Example 8

[0111] The granulated asphalt mixture additive used is the same as in Example 7, the storage temperature is 70° C., the storage time is 48 h, and the rest is the same as in Example 1.

[0112] Example 9

[0113] The granulated asphalt mixture additive used is the same as in Example 7, the storage temperature is 70° C., the storage time is 72 h, and the rest is the same as in Example 1.

[0114] Comparative Example 7

[0115] The granulated asphalt mixture additive used is the same as in Example 7, the storage temperature is 25° C., the storage time is 24 h, and the rest is the same as in Example 1.

[0116] Comparative Example 8

[0117] The granulated asphalt mixture additive used is the same as in Example 7, the storage temperature is 25° C., the storage time is 48 h, and the rest is the same as in Example 1.

[0118] Comparative Example 9

[0119] The granulated asphalt mixture additive used is the same as in Example 7, the storage temperature is 25° C., the storage time is 72 h, and the rest is the same as in Example 1.

[0120] The results of the agglomeration rate determination in Examples 7-9 and Comparative Examples 7-9 are shown in Table 3, and the agglomeration effect is shown in Appendix Figure 6 , Attachment Figure 7 , including Figure 6 From left to right in the figure are schematic diagrams of the agglomeration effects of Example 7, Example 8, and Example 9; Figure 7 From left to right in the figure are the agglomeration effects of Comparative Example 7, Comparative Example 8, and Comparative Example 9.

[0121] Table 3 Results of the determination of the agglomeration rate of rock asphalt and asphalt premix particles

[0122]

[0123]

[0124] The results in Table 3 show that when the rock asphalt and asphalt premixed particles are stored at room temperature at 25°C, the agglomeration rate of the granulated additive is less than 5% within 72 hours of storage at room temperature. Figure 7 It can be seen that the granular additive is almost not clumped after being stored at room temperature for 72 hours, indicating that the granular additive has good storage stability when the stacking height is 1m at room temperature. When the stacking height is 1m, the granular additive is stored at 70℃ for 72 hours continuously and the clumping rate is 5-7%. It can be seen from the table that the granular additive has good storage stability when stored at 70℃ for 2 days, and has better stability when stored for 3 days.

[0125] It will be easily understood by those skilled in the art that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for testing the storage stability of granulated asphalt mixture additives, It is characterized in that The following steps are involved: (1) Taking a predetermined mass of the granulated asphalt mixture additive to be tested, spreading it into a predetermined container with a predetermined area as the sample to be tested; (2) Determine the pressure load according to the stacking height and particle packing density of the simulated storage conditions, and apply the corresponding pressure load to the sample to be tested obtained in step (1); set the temperature load according to the upper limit of the storage temperature range, and apply the corresponding temperature load to the sample to be tested obtained in step (1); continue the pressure load and temperature load conditions for a preset time; (3) performing an agglomeration rate test on the sample to be tested that has undergone the storage condition simulation of step (2), and judging the storage stability of the granulated asphalt mixture additive to be tested based on the agglomeration rate test result and the principle that the higher the agglomeration rate, the worse the storage stability of the granulated asphalt mixture additive to be tested; The pressure load σ is determined in step (2) and is specifically calculated according to the following formula: σ=ρ·g·h Where ρ is the bulk density, g is the acceleration due to gravity, and h is the stacking height.

2. The method for detecting storage stability of a granulated asphalt mixture additive according to claim 1, It is characterized in that The temperature load in step (2) is between 50-70°C.

3. The method for detecting storage stability of a granulated asphalt mixture additive according to claim 1, It is characterized in that The preset duration in step (2) is greater than or equal to 1 hour.

4. The method for detecting storage stability of a granulated asphalt mixture additive according to claim 3, It is characterized in that The preset duration in step (2) is between 48 and 72 hours.

5. The method for detecting storage stability of a granulated asphalt mixture additive according to claim 1, It is characterized in that The specific judgment principle of step (3) is as follows: when the agglomeration rate of the sample to be tested exceeds a preset agglomeration rate threshold, it is judged that the stability of the sample to be tested is poor; otherwise, it is judged that the stability of the sample to be tested is good.

6. The method for detecting storage stability of a granulated asphalt mixture additive according to claim 5, It is characterized in that The agglomeration rate threshold is between 5% and 10%.

7. The method for detecting storage stability of a granulated asphalt mixture additive according to claim 6, It is characterized in that The agglomeration rate threshold is 5%.

8. The method for detecting storage stability of a granulated asphalt mixture additive according to any one of claims 5 to 7, It is characterized in that The preset duration in step (2) is set according to the following principles: A reference sample with good storage stability is stored under a preset pressure load and temperature load for a period of time so that the agglomeration rate of the reference sample with good storage stability is within a preset agglomeration rate range, and the period of time is determined as the preset period of time; The lower limit of the preset clumping rate range is 0.5 times the clumping rate threshold, and the upper limit is 2 times the clumping rate threshold.

9. The method for detecting storage stability of a granulated asphalt mixture additive according to claim 1, It is characterized in that The agglomeration rate is the mass M of the agglomerated sample. 1i The mass M of the granulated asphalt mixture additive to be tested 0 Specifically, the standard sieve can be used for screening until the residual mass of the granulated asphalt mixture additive that does not pass the standard sieve is stable, and the residual mass of the granulated asphalt mixture additive at this time is determined to be the mass of the agglomerated sample M 1i .

10. The method for detecting storage stability of a granulated asphalt mixture additive according to claim 9, It is characterized in that Screening is performed using a standard sieve slightly larger than the maximum size specification of the granulated asphalt mixture additive.

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