WO2023115827A1 - Method for detecting segregation degree of asphalt mixture - Google Patents

Abstract

Provided in the present invention is a method for detecting the segregation degree of an asphalt mixture. The detection method comprises the following steps: sorting aggregate particles with a particle size of ≥ 4.75 mm from a sample; soaking the aggregate particles in an organic solvent, and stirring same until the asphalt in the aggregate particles is completely dissolved; then extracting, drying and weighing same, and recording same as mass m1; screening and drying the weighed aggregate particles to obtain aggregate particles with a particle size of ＞ 2.36 mm, weighing same, and recording same as mass m2; and calculating to obtain a segregation degree L, wherein L = ((m1-m2)/m1)*100. In the present invention, the test method is provided from the perspective of the quantitative test of the segregation degree of an asphalt mixture, and a test basis is provided for controlling the segregation of the asphalt mixture, so that the working performance of the asphalt mixture is improved, and the quality of an asphalt concrete finished product is further ensured.

Description

Testing method for segregation degree of asphalt mixture technical field

The invention relates to the technical field of highway engineering materials, in particular to a detection method for the segregation degree of asphalt mixture.

Background technique

Asphalt mixture is a widely used pavement material. The road performance of asphalt concrete is closely related to the working performance (workability) of asphalt mixture. Asphalt mixture is composed of coarse and fine aggregates, fillers, asphalt binder, etc. Composition. Before the asphalt concrete is formed, the hot mix asphalt mixture is in a loose and cohesive state after mixing. Due to the characteristics of the asphalt mixture composition, if the mix ratio is not designed properly, or the construction control is improper during construction , there may be problems such as thickness segregation and temperature segregation of the mixture. These segregations will cause large deviations in the uniformity of the formed asphalt concrete pavement structure. The resistance to deformation, rutting, water damage and fatigue of asphalt concrete The performance will be affected, and the damage to the performance of the asphalt concrete pavement structure will be intensified with the increase of the segregation degree of the asphalt mixture.

Controlling the working performance of asphalt mixture in good condition is a common problem faced by asphalt pavement technicians, but there is a lack of quantitative testing methods for the working performance of asphalt mixture - segregation test.

Contents of the invention

In order to solve the above problems, the main purpose of the present invention is to provide a detection method for the segregation degree of asphalt mixture, which provides a test basis for controlling the segregation of asphalt mixture, thereby improving the working performance of asphalt mixture, and then ensuring the quality of asphalt concrete The quality of the finished product.

In order to achieve the above object, the present invention provides a detection method for the segregation degree of asphalt mixture.

The detection method of the asphalt mixture segregation degree comprises the following steps:

Sorting aggregate particles with a particle size ≥ 4.75mm from the sample;

Soak the aggregate particles in an organic solvent, and stir until the asphalt in it is completely dissolved; then extract, dry and weigh, and record it as mass m1;

Sieve, dry and weigh the aggregate particles to obtain aggregate particles with a particle diameter > 2.36 mm, weigh them, and record them as mass m2;

Calculate the resolution L, L=((m1-m2)/m1)*100.

Further, the asphalt mixture is sampled according to the quartering method to obtain the sample; wherein the asphalt mixture is a fine-grained, medium-grained or coarse-grained mixture.

Further, the asphalt mixture is a fine-grained mixture, which is specifically prepared by mixing coarse aggregate, fine aggregate, mineral powder filler and asphalt at 130-170°C and cooling to room temperature.

Further, the coarse aggregate is formed by combining the coarse aggregate with the first particle size, the coarse aggregate with the second particle size and the coarse aggregate with the third particle size;

Wherein, the particle diameters of the coarse aggregate with the first particle size, the coarse aggregate with the second particle size and the coarse aggregate with the third particle size are 10-15 mm, 6-10 mm and 3-6 mm in sequence.

Further, in the asphalt mixture, the mass percentages of the coarse aggregate with the first particle size, the coarse aggregate with the second particle size and the coarse aggregate with the third particle size are 15-25%, 17%. ~30% and 13~25%.

Further, the particle size of the fine aggregate is less than 2.36mm, and the mass percentage of the fine aggregate in the asphalt mixture is 26-36%.

Further, the mass percentage of the mineral powder filler in the asphalt mixture is 2-6%, and the mass percentage of the asphalt is 3.84-5.66%.

Further, the mass of the sample is 1000-1500g.

Further, the organic solvent is trichlorethylene solution or kerosene, and the soaking time is ≥30min.

Further, the drying temperature is 105±5° C., and the drying time is 3-5 hours.

The invention proposes a test method from the perspective of measuring the segregation of the asphalt mixture, and provides a test basis for controlling the segregation of the asphalt mixture, thereby improving the working performance of the asphalt mixture and ensuring the quality of the finished asphalt concrete.

The detection method in the invention is simple and fast, and can indirectly judge whether the asphalt mixture ratio of asphalt mixture is within the optimal value range by detecting the segregation degree, so as to provide guidance for the practical application of the asphalt mixture.

Description of drawings

Various other advantages and benefits will become apparent to those of ordinary skill in the art upon reading the following detailed description of the preferred embodiment. The drawings are only for the purpose of illustrating a preferred embodiment and are not to be considered as limiting the invention. Also throughout the drawings, the same reference numerals are used to designate the same parts. In the attached picture:

Fig. 1 is a schematic flowchart of a method for detecting segregation degree of asphalt mixture provided by an embodiment of the present invention.

Detailed ways

Exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. Although exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be embodied in various forms and should not be limited by the embodiments set forth herein. Rather, these embodiments are provided for more thorough understanding of the present disclosure and to fully convey the scope of the present disclosure to those skilled in the art.

The present invention utilizes the adhesiveness of asphalt binder at high temperature (130-170°C) and the thickness of the oil film on the surface of gravel and filler covered by the binder in the mixture, etc., to design a method for testing the segregation degree of asphalt mixture quantification method.

As shown in Figure 1, the detection method of the segregation degree of the asphalt mixture comprises the following steps:

The asphalt mixture is sampled according to the quartering method to obtain samples; wherein, the mass of the samples is within the range of 1000-1500g.

The asphalt mixture can be a fine-grained, medium-grained or coarse-grained mixture. The fine-grained mixture can be, for example, AC-10, AC-13 asphalt mixture; the medium-grained mixture can be, for example, AC-16, AC-20 asphalt mixture; coarse-grained mixture can be AC-25, AC-30 asphalt mixture, for example. When the fine-grained mixture is used, the mass of the sample can be 1000g; when the medium-grained mixture is used, the sample can be 1200g; when the coarse-grained mixture is used, the sample can be 1500g.

In the embodiment of the present invention, AC-13 fine-grained mixture is used, specifically, coarse aggregate, fine aggregate, mineral powder filler and asphalt are mixed at 130-170°C and then cooled to room temperature.

Wherein, the coarse aggregate is formed by combining coarse aggregate with the first particle size, coarse aggregate with the second particle size and coarse aggregate with the third particle size.

The particle diameters of the coarse aggregate with the first particle size, the coarse aggregate with the second particle size and the coarse aggregate with the third particle size are 10-15mm, 6-10mm and 3-6mm in sequence.

The mass percentages of the coarse aggregate with the first particle size, the coarse aggregate with the second particle size and the coarse aggregate with the third particle size are 15-25%, 17-30% and 13-25% in sequence.

The particle size of the fine aggregate is below 2.36mm, and the mass percentage of the fine aggregate is 26-36%.

The mass percentage of mineral powder filler is 2-6%.

The mass percentage of asphalt is 3.84-5.66%.

Sorting aggregate particles with a particle size ≥ 4.75mm from the sample; note that when sorting, the action should be gentle to avoid falling off of the fine aggregate adhered to the aggregate particles.

Use trichlorethylene solution or kerosene to soak the coarse aggregate particles for ≥30 minutes, and stir with a glass rod until the asphalt is completely dissolved. The standard is that there is no asphalt on the surface of the aggregate.

Extract the above-mentioned aggregates, dry them at 105±5°C for 3-5 hours, weigh them, and record them as mass m1.

Sieve, dry and weigh the aggregate particles to obtain aggregate particles with a particle diameter > 2.36 mm, weigh them, and record them as mass m2.

Calculate the resolution L, L=((m1-m2)/m1)*100.

Generally, the larger the value of segregation L, the better the segregation resistance of the asphalt mixture.

However, there is an upper limit for the segregation degree L. First, the maximum asphalt content of the mixture is determined according to the test method for the maximum asphalt content of the asphalt mixture, and then the asphalt mixture is prepared by using the maximum asphalt content, and finally the segregation degree L obtained by the above method is measured. is the upper limit value.

The optimum asphalt ratio of asphalt mixture corresponds to the optimum degree of segregation, and it can be indirectly judged whether the asphalt ratio of asphalt mixture is within the optimal range by detecting the degree of segregation of asphalt mixture. For a certain type of asphalt mixture, it is necessary to determine its optimal asphalt ratio according to the design method of the mix ratio, and within the fluctuation range of the optimal asphalt ratio (plus or minus 0.3%), the corresponding segregation L is the maximum value of the asphalt mixture. good range value.

The method for detecting the segregation degree of asphalt mixture in the present invention will be described in detail below through specific examples.

Example 1:

1. Take the fine-grained asphalt mixture that has been mixed and meet the requirements of the mixing temperature (130-170°C), divide the sample by quartering, take two samples diagonally, and the sampling mass is 1000g.

2. Put the sample into a clean stainless steel square pan, spread the mixture gently with a shovel to form a thin layer of separated and non-overlapping aggregates, and cool to room temperature.

3. From the cooled samples, sort out the aggregate particles with a particle size above 4.75mm.

4. Put the sorted aggregate particles into a glass beaker, soak them in trichlorethylene for 30 minutes, and stir them with a glass rod to dissolve the asphalt and separate the fine aggregates from the aggregate surface; then extract and dry at 105°C 3h, weighing, mass recorded as m1.

5. Sieve the dry and weighed mixture with a 2.36mm square hole sieve, weigh the remaining gravel on the sieve, and record the mass as m2.

6. In order to ensure the accuracy, the above test is performed twice in parallel to calculate the segregation degree, which is recorded as L, the calculation formula L=((m1-m2)/m1)*100, and the results of the two calculations cannot exceed the average value 3%.

In the present invention, the degree of segregation L characterizes the ratio of asphalt adhered to the coarse aggregate, fine aggregate below 2.36 mm, and mineral powder filler to the total mass of asphalt mixture.

Examples 2-3 adopt the same test method as Example 1, the difference lies in the mass percent of coarse aggregate, fine aggregate, mineral powder filler and asphalt in the asphalt mixture, the ratio of asphalt and the process parameters in each step different. The parameters of each step in the detection methods of Examples 1 to 3 are now summarized, see Tables 1 to 2 for details.

Table 1 Summary of each component material of the asphalt mixture in Examples 1 to 3

Summary of each process parameter in the detection method of table 2 embodiment 1～3

At the same time, in the present invention, the segregation degree L is also calculated according to the detection method in Examples 1-3, and the oil-stone ratio in Examples 1-3 is calculated by using a conventional calculation method in the industry. See Table 3 for the results.

Summary of results of asphalt ratio and segregation in Table 3 Examples 1 to 3

group	Oil-stone ratio (%)	Resolution L
Example 1	4.0	15.8
Example 2	5.3	32.3
Example 3	5.6	34

It can be seen from Table 3 that the segregation degree L is obtained by the detection method in the present invention, and whether the asphalt-stone ratio of the asphalt mixture is within the optimal value range can be judged indirectly through the segregation degree L. As found by testing, the oil-stone ratio 5.3% in Example 2 is the best value, and its corresponding segregation degree L 32.3 is the best segregation degree value, and further obtains the range value of the corresponding segregation degree L in the oil-stone ratio 5.0～5.6% scope (27-34) is the preferred segregation value (including the preferred range value of 32.4, corresponding to the oil-stone ratio of 5.0-5.6%).

In combination with Example 1 and Example 3, it is not difficult to see that the asphalt-stone ratio in Example 1 is 4.0%, and the segregation degree L 15.2 is detected, which is lower than the preferred segregation degree range value, indicating that the segregation degree L value is on the low side, and the asphalt content On the low side; the asphalt ratio in embodiment 3 is 5.6%, detects and obtains segregation L 34, is the upper limit value of segregation range value, is greater than this value, will cause the asphalt content in the mixture to be on the high side.

The above is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed in the present invention can easily think of changes or Replacement should be covered within the protection scope of the present invention. Therefore, the protection scope of the present invention should be determined by the protection scope of the claims.

Claims (10)

1. A detection method for segregation degree of asphalt mixture, characterized in that it comprises the following steps:

   Sorting aggregate particles with a particle size ≥ 4.75mm from the sample;

   Soak the aggregate particles in an organic solvent, and stir until the asphalt in it is completely dissolved; then extract, dry and weigh, and record it as mass m1;

   Sieve, dry and weigh the aggregate particles to obtain aggregate particles with a particle diameter > 2.36 mm, weigh them, and record them as mass m2;

   Calculate the resolution L, L=((m1-m2)/m1)*100.
2. The detection method for the segregation degree of asphalt mixture according to claim 1, wherein the asphalt mixture is sampled by quartering to obtain the sample; wherein, the asphalt mixture is fine-grained or medium-grained or coarse-grained mixes.
3. The method for detecting the segregation degree of an asphalt mixture according to claim 1 or 2, wherein the asphalt mixture is a fine-grained mixture, specifically using coarse aggregate, fine aggregate, mineral powder filler and asphalt in the Prepared after stirring at 130-170°C and cooling to room temperature.
4. The method for detecting segregation degree of asphalt mixture according to claim 3, characterized in that, the coarse aggregate is a combination of coarse aggregate with the first particle size, coarse aggregate with the second particle size and coarse aggregate with the third particle size form;

   Wherein, the particle diameters of the coarse aggregate with the first particle size, the coarse aggregate with the second particle size and the coarse aggregate with the third particle size are 10-15 mm, 6-10 mm and 3-6 mm in sequence.
5. The detection method for the segregation degree of asphalt mixture according to claim 4, characterized in that, in the asphalt mixture, the first particle diameter coarse aggregate, the second particle diameter coarse aggregate and the second particle diameter The mass percentages of the coarse aggregate with three particle sizes are 15-25%, 17-30% and 13-25%.
6. The detection method for the segregation degree of asphalt mixture according to claim 3, characterized in that, the particle diameter of the fine aggregate is below 2.36 mm, and the mass percentage of the fine aggregate in the asphalt mixture is 26 ~36%.
7. The method for detecting the segregation degree of asphalt mixture according to claim 3, characterized in that the mass percentage of the mineral powder filler in the asphalt mixture is 2-6%, and the mass percentage of the asphalt is 3.84-6%. 5.66%.
8. The method for detecting segregation degree of asphalt mixture according to claim 1, characterized in that the mass of the sample is 1000-1500 g.
9. The method for detecting segregation degree of asphalt mixture according to claim 1, characterized in that, the organic solvent is trichlorethylene solution or kerosene, and the soaking time is ≥30min.
10. The method for detecting segregation degree of asphalt mixture according to claim 1, characterized in that, the drying temperature is 105±5° C., and the drying time is 3-5 hours.

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