CN115124282B - Asphalt pavement old material recycling mixture based on SBS and epoxy resin system and preparation method thereof - Google Patents

Abstract

The invention relates to an asphalt pavement old material recycling mixture based on SBS and epoxy resin system and a preparation method thereof. The recycling mixture includes an epoxy resin system mixture, SBS, matrix asphalt and asphalt pavement old material, wherein according to the quality Calculating the parts, the epoxy resin system is 10-50 parts, the SBS is 4-10 parts, the base asphalt is 0-66 parts, and the old asphalt pavement material is 20-86 parts; during preparation, according to the binder of the old asphalt pavement material Content: Add a certain amount of epoxy resin system mixture and SBS into the mixing pot and stir; then pour the base asphalt into the mixing pot and stir; finally, put the dried asphalt pavement old material into the mixing pot containing the epoxy resin system mixture, SBS and The matrix asphalt is stirred in a mixing pot to form a regenerated mixture; the invention greatly improves the low temperature and fatigue properties of the epoxy resin system regenerated mixture, reduces the demand for mineral aggregates in pavement materials, and at the same time reduces the need for epoxy resin system mixtures. consumption and reduce the cost of road construction.

Description

A kind of asphalt pavement old material recycling mix based on SBS and epoxy resin system Materials and preparation methods

Technical field

The invention relates to an asphalt pavement old material recycling mixture based on SBS and epoxy resin systems and a preparation method thereof, and belongs to the technical field of road engineering materials.

Background technique

The peak period of highway construction in our country was concentrated in the first 10 years of the 21st century. As of 2020, nearly one-third of the highways that have been built in our country have a service life of more than 15 years. Therefore, it will be a period of intensive maintenance demand. Asphalt pavement The output of old materials will continue to increase. In order to better deal with the recycling problem of old asphalt pavement materials, asphalt pavement recycling technology is also receiving more and more attention. With the rising cost of road construction materials and increasingly stringent environmental protection policies, the demand for high-mixing of asphalt pavement recycling technology is becoming increasingly apparent. However, when the amount of old asphalt pavement materials in the recycled mixture is large, the recycled asphalt mixture will have problems such as poor water stability, cracking resistance, and fatigue resistance.

Although the currently used regenerants and regeneration methods can restore the performance of asphalt to a certain level, the amount of old asphalt pavement materials in the recycled mixture usually does not exceed 50%. If the amount of old asphalt pavement material in the recycled mixture is increased, it is impossible to avoid the poor fatigue performance of the recycled mixture due to insufficient deformation ability. Therefore, there is an urgent need to develop a new type of asphalt pavement old material recycling mixture and its preparation method. On the premise of ensuring the dosage of old materials, the fatigue or flexibility performance of the recycled mixture is improved.

Contents of the invention

The invention provides an asphalt pavement old material recycling mixture and a preparation method based on an SBS and epoxy resin system. It is an efficient, simple process and environmentally friendly material and preparation method, which improves the various road properties of the recycled asphalt mixture. Use performance.

The technical solutions adopted by the present invention to solve the technical problems are:

An asphalt pavement old material recycling mixture based on SBS and epoxy resin system, including epoxy resin system mixture, SBS, matrix asphalt and asphalt pavement old material, wherein, calculated in terms of mass parts, the epoxy resin system is 10 -50 parts, SBS is 4-10 parts, base asphalt is 0-66 parts, old asphalt pavement material is 20-86 parts;

As a further preference of the present invention,

The epoxy resin system mixture includes liquid epoxy resin and a curing agent, and the liquid epoxy resin and the curing agent are uniformly mixed at a preset temperature to form an epoxy resin system mixture;

As a further preference of the present invention, the mass ratio of liquid epoxy resin and curing agent is 50:50-60:40, and the liquid epoxy resin and curing agent are uniformly mixed at a temperature of 50°C-80°C to form an epoxy resin system. mixture;

As a further preference of the present invention, the liquid epoxy resin is bisphenol A type or bisphenol F type epoxy resin;

As a further preference of the present invention, the SBS is wet SBS or dry SBS.

A method for preparing an asphalt pavement old material recycling mixture based on SBS and epoxy resin systems, specifically including the following steps:

Step S1: Calculate the mass fraction of the epoxy resin system mixture and SBS based on the binder content of the old asphalt pavement material;

Step S2: Heat each component in the epoxy asphalt system mixture, and heat the matrix asphalt to a fluid state;

Step S3: Mix each component in the heated epoxy asphalt system mixture according to the proportion, pour it into a mixing pot and stir evenly to form an epoxy resin system mixture;

Step S4: Add the epoxy resin system mixture and SBS into the mixing pot and stir evenly;

Step S5: Pour the heated matrix asphalt into the mixing pot and continue stirring;

Step S6: Dry the old asphalt pavement material and put it into a mixing pot containing the epoxy resin system mixture, SBS and matrix asphalt to stir to prepare a recycling mixture;

As a further preference of the present invention, in step S4, the epoxy resin system mixture and SBS are added to the mixing pot and the stirring time is 60-120s;

As a further preference of the present invention, in step S5, the matrix asphalt is poured into the mixing pot and continued to stir for 30-90s;

As a further preference of the present invention, in step S6, the old asphalt pavement material is dried and then put into a mixing pot containing the epoxy resin system mixture, SBS and matrix asphalt and stirred for 90 seconds;

As a further preference of the present invention, the mixing and stirring temperature in steps S1 to S6 is 160°C-180°C.

Through the above technical solutions, compared with the existing technology, the present invention has the following beneficial effects:

1. In the recycled mixture provided by the present invention, on the premise of ensuring the mixing amount of old asphalt pavement materials, an epoxy resin system mixture and SBS are added. The epoxy resin system mixture improves the high-temperature rutting resistance of the mixture, and SBS improves The strength and high and low temperature resistance of the epoxy resin system mixture improve the fatigue and flexibility properties of the recycled mixture;

2. In the regenerated mixture provided by the present invention, no new aggregate can be added, only old asphalt pavement materials can be added to generate noise mixture, and the amount of old materials can reach 100%, realizing high-intensity regeneration of old asphalt mixtures;

3. In the recycled mixture provided by the present invention, factors such as old material gradation, oil-stone ratio, and mineral material material have little impact on the performance of the prepared recycled mixture. Appropriate changes in the amount of the epoxy resin system mixture and SBS can Reduce the impact of these factors;

4. In the regenerated mixture provided by the present invention, the SBS is wet SBS or dry SBS. Using dry SBS can effectively improve the compatibility between SBS and the binder in the old material, and achieve more effective performance improvement;

5. The preparation method of the old asphalt pavement material recycling mixture based on the SBS and epoxy resin system provided by the present invention has simple processing technology, high safety, low construction difficulty, and breaks through the low content of old asphalt pavement materials and short service life. Technical bottlenecks, optimize and improve the performance of epoxy recycled mixtures with long-life pavement material potential, achieve efficient and high-quality reuse of asphalt pavement, comply with national dual carbon goals and regulatory requirements, and have important theories for promoting green and sustainable development of highway transportation meaning and practical value.

Detailed ways

In order to solve the problems in the background technology that when the amount of old asphalt pavement materials in the recycled mixture is large, the recycled asphalt mixture is prone to poor water stability, cracking resistance and fatigue resistance, this application has gone through many tests, It was found that epoxy asphalt can be used to recycle old asphalt pavement materials, and at the same time, the content of old asphalt pavement materials can reach 100%. However, it was found that although the water stability and low temperature performance of the epoxy asphalt recycled mixture are not as good as those of new epoxy asphalt. The performance of the mixture is very close. The addition of epoxy asphalt improves the high-temperature rutting resistance of the recycled mixture, but the fatigue performance is poor compared with the new epoxy asphalt mixture. This is because compared to unaged asphalt mixture, the aged asphalt mixture has a higher modulus and is more brittle, and the epoxy asphalt material is also a brittle material. The elastic modulus of the epoxy asphalt mixture becomes larger after curing. , The deformation coordination ability becomes poor, and cracks are prone to occur under low temperature conditions or repeated loads. When the old asphalt pavement material is mixed with epoxy asphalt, the old asphalt pavement material becomes "more brittle", causing the brittleness of the mixture to be further amplified, resulting in insufficient deformation ability and poor fatigue performance.

Therefore, in order to improve the fatigue performance of the epoxy asphalt recycled mixture, this application continued to conduct relevant tests and found that using flexible polymers to soften and toughen the epoxy asphalt mixture can effectively improve the fatigue properties of the epoxy asphalt. Styrene -Butadiene-styrene triblock copolymer (SBS) has better toughening and other performance improvement effects and a lower price; therefore, SBS can effectively improve the strength and high and low temperature properties of epoxy asphalt, and has good Comprehensive modification effect.

Next are multiple embodiments given in this application based on the above principles.

Example 1

The asphalt from the old asphalt pavement material was extracted, and the PG grade of the asphalt in the old asphalt pavement material was measured to be PG82-16. The aggregate gradation of the old material is shown in the table below:

Prepare the grading of old materials, sieve the old materials into two grades of materials through a 4.75mm sieve, and then mix 25% of the fine grade old materials and 75% of the coarse grade old materials to form the adjusted RAP material. Add 10 parts, 20 parts, 30 parts, 40 parts and 50 parts of epoxy resin system mixture to the mixture respectively, and then add 5 parts of old material cementing material to the above mixture. Dry SBS. At the same time, new aggregates with the same gradation were used as the control group, and the same content of epoxy resin system and SBS were added to prepare new epoxy asphalt mixtures.

The specific preparation method is as follows:

Step S1: Dry the old asphalt pavement materials crushed by the mixer in an oven above 120°C for 2-3 hours;

Step S2: Heating the components of the epoxy asphalt system mixture: heating component A and group B of the epoxy resin system to 60°C respectively, holding for 10 minutes, and heating the matrix asphalt to a fluid state;

Step S3: Mix component A and component B of the heated epoxy resin system mixture in a ratio of 56:44, pour it into a container, and stir with a glass rod for 4 minutes to obtain an epoxy resin system mixture;

Step S4: After weighing the required amount, add the mixed epoxy resin system mixture and SBS into the mixing pot, and stir at 180°C for 90 seconds;

Step S5: Pour the heated matrix asphalt into the mixing pot used for mixing the mixture, and stir at 180°C for 60 seconds;

Step S6: Put the heated old asphalt pavement materials into the mixing pot and mix at 180°C for 90 seconds to make a recycled mixture;

Step S7: After curing the specimen at 60°C for 4 days, measure various properties of the mixture.

First, the high-temperature performance of the recycled mixture was measured, and the dynamic stability of the specimen was measured in a rutting instrument. The results are as follows:

As can be seen from the above table, adding epoxy resin alone cannot restore the high-temperature performance of the mixture to the level of the new epoxy mixture, while the high-temperature performance of the mixture after adding SBS is closer to the level of the new epoxy mixture.

Secondly the low temperature properties of the recycled mix were measured, the effect of which was measured by trabecular bending tests. The cured rut plate specimens were cut into 250 mm × 30 mm × 35 mm prism trabecular specimens. Trabecular bending tests were performed at -10°C. The test results are shown in the table below:

As can be seen from the table above, SBS reduces the modulus of the mixture at low temperatures at all epoxy resin system dosages, making the low-temperature modulus closer to that of new epoxy asphalt mixtures.

Finally, the fatigue properties of the recycled mixture were measured, and the fatigue properties were measured by trabecular bending fatigue tests. The cured rut plate specimens were cut into 250 mm × 30 mm × 35 mm prism trabecular specimens. Three-point loading is adopted, and the loading waveform is a 10Hz continuous half-sine wave. Loading is performed at a stress ratio of 0.4. The test results are shown in the following table:

As can be seen from the above table, adding SBS can greatly increase the number of load cycles of the epoxy recycled mixture, effectively improve the fatigue performance of the epoxy recycled mixture, and make the fatigue performance of the recycled mixture better than that of new epoxy mixture.

Example 2

The asphalt from the old asphalt pavement material was extracted, and the PG grade of the asphalt in the old asphalt pavement material was measured to be PG82-16. The aggregate gradation of the old material is shown in the table below:

Add 30 parts and 40 parts by mass of the epoxy resin system to the old asphalt pavement materials respectively, and then add 4 parts, 6 parts, 8 parts and 10 parts by mass of the old material cementing material to the above mixture. Ordinary wet SBS. The specific preparation method is as follows:

Step S1: Dry the old asphalt pavement materials crushed by the mixer in an oven above 120°C for 2-3 hours;

Step S2: Heating the components of the epoxy asphalt system mixture: heating component A and group B of the epoxy resin system to 60°C respectively, holding for 10 minutes, and heating the matrix asphalt to a fluid state;

Step S3: Mix component A and component B of the heated epoxy resin system mixture in a ratio of 56:44, pour it into a container, and stir with a glass rod for 4 minutes to obtain an epoxy resin system mixture;

Step S4: After weighing the required amount, add the mixed epoxy resin system mixture and SBS into the mixing pot, and stir at 180°C for 90 seconds;

Step S5: Pour the heated matrix asphalt into the mixing pot used for mixing the mixture, and stir at 180°C for 60 seconds;

Step S6: Put the heated old materials into a mixing pot and mix at 180°C for 90 seconds to make a regenerated mixture;

Step S7: The specimen is cured at 60°C for 4 days, and then the various properties of the mixture are measured.

The high-temperature properties of the recycled mix were first measured, as measured by rutting tests. A standard rut plate specimen was prepared and then placed in a rutting instrument to measure the dynamic stability of the specimen. The test results are as follows:

As can be seen from the above table, as the SBS content increases, the dynamic stability of the mixture gradually decreases, effectively reducing the modulus of the mixture. By changing the amount of SBS, the amount of the epoxy resin system can be adjusted. .

Next, the low-temperature properties of the recycled mix were measured. The impact of the low-temperature performance of the mix was measured through trabecular bending tests. The cured rut plate specimens were cut into 250 mm × 30 mm × 35 mm prism trabecular specimens. Trabecular bending tests were performed at -10°C. The test results are shown in the table below.

It can be seen from the table that under all epoxy resin system dosages, increasing the SBS dosage can reduce the modulus of the recycled mixture at low temperatures. Through interpolation, it can be concluded that when the SBS and epoxy resin systems At 5.5% and 30% content respectively, the modulus of the recycled mix at low temperature is the same as that of the recycled mix at 4% and 40% SBS and epoxy resin systems respectively.

Finally, the fatigue properties of the recycled mixture were measured, and the fatigue properties were measured by trabecular bending fatigue tests. The cured rut plate specimens were cut into 250 mm × 30 mm × 35 mm prism trabecular specimens. Three-point loading is adopted, and the loading waveform is a 10Hz continuous half-sine wave. Loading is performed at a stress ratio of 0.4. The test results are shown in the following table:

As can be seen from the table above, adding SBS can greatly increase the number of load cycles of the epoxy recycled mixture and effectively improve the fatigue performance of the epoxy recycled mixture.

It can be seen from Example 1 and Example 2 that by adding and increasing the amount of SBS, the amount of epoxy resin system can be reduced and the performance of the regenerated mixture can be reached to a similar level. Therefore, SBS can be used to replace part of the epoxy resin system to a certain extent and reduce the cost of pavement construction.

In summary, according to all the embodiments involved in an asphalt pavement old material recycling mixture based on SBS and epoxy resin system and its preparation method, the epoxy resin system mixture and SBS are used to effectively restore the performance of the recycled mixture, It can improve the fatigue, low temperature and other road performance of the recycled mixture. In addition, SBS can replace part of the epoxy resin system, thereby reducing the amount of epoxy resin system in the recycled mixture, saving resources and pollution while reducing the cost of pavement construction.

It will be understood by those skilled in the art that, unless otherwise defined, all terms (including technical terms and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. It should also be understood that terms such as those defined in general dictionaries are to be understood to have meanings consistent with their meaning in the context of the prior art, and are not to be taken in an idealized or overly formal sense unless defined as herein. explain.

The meaning of "and/or" mentioned in this application means that each exists alone or both exist at the same time.

The meaning of "connection" in this application may be a direct connection between components or an indirect connection between components through other components.

Taking the above-mentioned ideal embodiments of the present invention as inspiration and through the above description, relevant workers can make various changes and modifications without departing from the scope of the technical idea of the present invention. The technical scope of the present invention is not limited to the content in the description, and must be determined based on the scope of the claims.

Claims (4)

1. A preparation method of an asphalt pavement old material recycling mixture based on an SBS and epoxy resin system is characterized by comprising the following steps: on the premise of ensuring the mixing amount of the old asphalt pavement material, adding the epoxy resin system mixture and SBS, wherein the epoxy resin system mixture improves the high-temperature rutting resistance of the recycled mixture, and the SBS improves the strength and high-low temperature property of the epoxy resin system mixture and improves the fatigue and flexibility of the recycled mixture;

the recycled mixture of the old asphalt pavement material comprises 10-50 parts by mass of epoxy resin system mixture, 4-10 parts by mass of SBS, 0-66 parts by mass of matrix asphalt and 20-86 parts by mass of old asphalt pavement material; the epoxy resin system mixture comprises liquid epoxy resin and a curing agent, and the liquid epoxy resin and the curing agent are uniformly mixed at a preset temperature to form the epoxy resin system mixture;

the method specifically comprises the following steps:

step S1: calculating the mass fraction of an epoxy resin system mixture and SBS (styrene butadiene styrene) according to the cementing material content of old asphalt pavement materials;

step S2: heating the components in the epoxy resin system mixture and heating the matrix asphalt to a fluid state;

step S3: mixing the components in the heated epoxy resin system mixture according to a proportion, and pouring the mixture into a stirring pot to be stirred uniformly to form the epoxy resin system mixture;

step S4: adding the epoxy resin system mixture and SBS into a stirring pot, and stirring and uniformly mixing;

step S5: pouring the heated matrix asphalt into a stirring pot for continuous stirring;

step S6: drying old asphalt pavement materials, and then adding the dried old asphalt pavement materials into a stirring pot containing an epoxy resin system mixture, SBS and matrix asphalt for stirring to prepare a recycling mixture;

the SBS is dry SBS;

in the step S4, adding the epoxy resin system mixture and SBS into a stirring pot, and stirring for 60-120S;

in the step S5, pouring the matrix asphalt into a stirring pot and continuously stirring for 30-90S;

in the step S6, the old asphalt pavement material is dried and then put into a stirring pot containing the epoxy resin system mixture, SBS and matrix asphalt to be stirred for 90S.

2. The method for preparing the recycled asphalt pavement old material mixture based on the SBS and epoxy resin system according to claim 1, which is characterized in that: the temperature of mixing and stirring in the step S1-the step S6 is 160-180 ℃.

3. The method for preparing the recycled asphalt pavement old material mixture based on the SBS and epoxy resin system according to claim 2, which is characterized in that: the mass ratio of the liquid epoxy resin to the curing agent is 50:50-60:40, and the liquid epoxy resin and the curing agent are uniformly mixed at the temperature of 50-80 ℃ to form an epoxy resin system mixture.

4. The method for preparing the recycled asphalt pavement old material mixture based on the SBS and epoxy resin system according to claim 3, which is characterized in that: the liquid epoxy resin is bisphenol A type or bisphenol F type epoxy resin.