CN111960729A

CN111960729A - Cold-laid modified asphalt mixture and preparation method and application thereof

Info

Publication number: CN111960729A
Application number: CN202010812379.1A
Authority: CN
Inventors: 李蕊; 谢杰; 王明
Original assignee: Changan University
Current assignee: Changan University
Priority date: 2020-08-13
Filing date: 2020-08-13
Publication date: 2020-11-20
Anticipated expiration: 2040-08-13
Also published as: CN111960729B

Abstract

The invention relates to a cold-paving type modified asphalt mixture and a preparation method and application thereof, comprising a cold-paving solvent, petroleum resin, road petroleum asphalt and mineral aggregate; the cold paving solvent comprises a viscosity reducer, catalytic pyrolysis rubber powder and an organic solvent; the mineral aggregate is composed of coarse aggregate, fine aggregate and mineral powder; 0.39-0.42 part of viscosity reducer, 1.30-1.40 parts of petroleum resin, 2.61-2.94 parts of catalytic cracking rubber powder, 5.59-8.82 parts of organic solvent, 26.06-29.39 parts of road petroleum asphalt and 956.94-961.82 parts of mineral aggregate. According to the invention, the viscosity reducer and the catalytic cracking rubber powder are added, so that the consumption of asphalt is reduced, the consumption of an organic solvent is increased, and the cost is reduced; meanwhile, the cold paving is realized, the construction workability is improved, the storage time is long, the energy is saved, the environment is protected, the road operation cost is reduced, and the crack resistance is high.

Description

Cold-laid modified asphalt mixture and preparation method and application thereof

Technical Field

The invention belongs to the technical field of road construction materials, and relates to a cold-laid modified asphalt mixture, and a preparation method and application thereof.

Background

When the asphalt pavement is used, due to vehicle load and environmental acting force, a pit is inevitably formed. The driving comfort is reduced, the damage of the road surface is accelerated, and meanwhile, the conflict points of the traffic flow are increased invisibly. The existence of the road conflict point inevitably leads to the improvement of the occurrence rate of the traffic accident, and particularly when the vehicle runs under unfavorable conditions such as a road at night, a road with large traffic flow, a bridge and the like, the occurrence rate of the traffic accident is higher, and the caused accident is more serious. Therefore, the asphalt mixture is urgently needed to timely and effectively repair the pits on the road.

Most road paves use the hot mix and warm mix asphalt mixture, because all have certain drawback: the construction process is complicated, highly dependent on temperature, the use of the mixture is greatly influenced by seasons, the effective construction time is short, a secondary aging phenomenon can be generated in the transportation and paving processes of the asphalt mixture to influence the performance of the asphalt, and high energy consumption and environmental pollution are also accompanied in the whole process. Therefore, the hot-mix and warm-mix asphalt mixture cannot meet the requirement of timely and fast repairing pits of the asphalt pavement.

Although researchers also propose to modify the asphalt mixture by using the refrigerant at present, the types of the additives used in the modification are more, and the content of the refrigerant used for the modification is low, and the refrigerant is generally an organic solvent, is volatile, has low construction performance and poor storage performance.

Disclosure of Invention

Aiming at the technical problems of the existing modified asphalt mixture in the background technology, the invention discloses a cold-paving type modified asphalt mixture and a preparation method thereof, the consumption of asphalt is reduced and the consumption of organic solvent is increased by adding viscosity reducer and catalytic cracking rubber powder, the modified asphalt mixture has good cold paving performance, and the cost is reduced; meanwhile, when the modified asphalt mixture is used for road construction, road paving and leveling can be carried out in a low-temperature environment, construction workability is improved, cracking resistance is high, storage time is long, energy is saved, environment is protected, and road operation cost is reduced.

In order to achieve the purpose, the invention adopts the technical scheme that:

a cold-paving type modified asphalt mixture comprises a cold-paving solvent, petroleum resin, road petroleum asphalt and mineral aggregate; the cold paving solvent comprises a viscosity reducer, catalytic pyrolysis rubber powder and an organic solvent; the mineral aggregate is composed of coarse aggregate, fine aggregate and mineral powder; the viscosity reducer is prepared from 0.39-0.42 part by weight of petroleum resin 1.30-1.40 parts by weight, 2.61-2.94 parts by weight of catalytic cracking rubber powder, 5.59-8.82 parts by weight of organic solvent, 26.06-29.39 parts by weight of road petroleum asphalt and 956.94-961.82 parts by weight of mineral aggregate.

Furthermore, the weight of the mineral powder is 3-7% of the weight of the mineral aggregate.

A preparation method of a cold-laid modified asphalt mixture comprises the following steps:

1) adding catalytic cracking rubber powder when the temperature of the road petroleum asphalt reaches 175-;

2) continuously adding the viscosity reducer into the step 1) until the viscosity reducer is completely dissolved, adding the petroleum resin, and stirring for 12-20min to obtain the composite modified asphalt;

3) cooling the prepared composite modified asphalt to about 85-100 ℃, adding an organic solvent, and stirring for 10-20min to prepare a cold-laid composite modified asphalt binder;

4) placing the coarse aggregate and the fine aggregate into a container, stirring for 90s at the temperature of 50-60 ℃, pouring the cold-paved composite modified asphalt binder prepared in the step 3), stirring for 90s, pouring the mineral powder, and stirring for 90 s; and preparing the cold-laid modified asphalt mixture.

Further, in the step 4), the Marshall initial stability value of the cold-laid modified asphalt mixture is 2.82-3.65 KN, and the Marshall forming stability value is 10.53-18.91 KN; the average bending tensile strength is 6.85 MPa; the average bending stiffness modulus is 2714 MPa; the maximum bending strain averaged 3402 μ.

When the cold-paving type modified asphalt mixture is used for cold paving, the cold paving solvent improves the cold paving performance of the cold-paving type modified asphalt mixture.

When the cold-paving type modified asphalt mixture is used for cold paving, the cold paving solvent prolongs the storage life of the cold-paving type modified asphalt mixture.

The invention has the beneficial effects that:

1. the cold-paving type modified asphalt mixture provided by the invention comprises a cold-paving solvent, petroleum resin, road petroleum asphalt and mineral aggregate; the cold paving solvent comprises a viscosity reducer, catalytic pyrolysis rubber powder and an organic solvent; the mineral aggregate is composed of coarse aggregate, fine aggregate and mineral powder. The cold paving solvent with excellent performance is added, so that the cold paving performance and the storage life of the asphalt mixture are improved; the viscosity reducer enables the comprehensive modified asphalt to reach a flowing state at normal temperature, and cold paving of the mixture is realized; meanwhile, the addition of the waste catalytic cracking rubber powder reduces the consumption of asphalt, thereby reducing the cost of asphalt mixture, recycling waste, saving energy and protecting environment.

2. In the cold-paving type modified asphalt mixture provided by the invention, 0.39-0.42 part of viscosity reducer, 1.30-1.40 parts of petroleum resin, 2.61-2.94 parts of catalytic cracking rubber powder, 5.59-8.82 parts of organic solvent, 26.06-29.39 parts of road petroleum asphalt and 956.94-961.82 parts of mineral aggregate; by adding the viscosity reducer and the catalytic cracking rubber powder, the using amount of the road petroleum asphalt is reduced, and the weight ratio of the organic solvent to the road petroleum asphalt is improved; the higher usage amount of the organic solvent can not only improve the workability of construction, but also avoid the volatilization of the organic solvent in the mixture, improve the storability of the cold-laid modified asphalt mixture, reduce the resource waste and the environmental pollution, and also reduce the road operation cost.

3. When the mineral aggregate is designed, the dosage of coarse aggregates with the maximum nominal particle size of 13.2mm and the dosage of fine aggregates with the particle size of below 0.6mm are reduced, more aggregates with medium particle size are contained, and the dosage of mineral powder is 3-7%, so that an s-shaped grading curve is formed, the high-temperature performance of the cold-laid modified asphalt mixture is ensured, and the low-temperature crack resistance is also considered.

4. The cold-paving type modified asphalt mixture has the advantages of no need of a heating construction process, small construction environmental pollution, adoption of cold paving during construction, rapidness, simplicity, no need of completely closed traffic and the like.

Detailed Description

The present invention will now be described in detail with reference to examples.

Examples 1 to 4

The cold-paving type modified asphalt mixture provided in the embodiment 1 to the embodiment 4 comprises a cold-paving solvent, petroleum resin, road petroleum asphalt and mineral aggregate; the cold paving solvent comprises a viscosity reducer, catalytic pyrolysis rubber powder and an organic solvent; the mineral aggregate is composed of coarse aggregate, fine aggregate and mineral powder.

Specific parts by weight in examples 1 to 4 are shown in table 1.

Table 1 examples 1 to 4 composition parts of cold-laid modified asphalt mixture

In the above examples 1 to 4, a total of 6 materials are included, and each material is specifically as follows:

1) the viscosity reducer is Sasobit REDUX; the Sasobit REDUX performance index is freezing point 72-83 deg.C, permeability at 25 deg.C 16-30 dmm.

2) The petroleum resin is C5 hydrogenated petroleum resin. The technical properties are shown in table 2.

TABLE 2 technical Properties of Petroleum resins

3) The catalytic cracking rubber powder is rubber powder treated by 3 per mill of modifier for 8 days.

Specifically, the preparation process of the catalytic cracking rubber powder comprises the following steps: and treating the waste tire rubber powder with 3 per mill of catalyst for 8 days to obtain the catalytic cracking rubber powder. The catalyst used was NaZSM-5(Si/Al 50) available from southern Kai university catalyst works.

4) The organic solvent is diesel oil, and the performance indexes of the diesel oil are that the flash point (closed end) is more than 65 ℃, the theoretical ignition point is 220 ℃, and the dynamic viscosity is 2.55-6.8 Pa.s at 20 ℃.

5) The road petroleum asphalt is SK90# asphalt with a moderate grade, and the technical performance is shown in Table 3.

TABLE 3 technical Property Table of road petroleum asphalt

Test items	Unit of	Test method	Test results
				Penetration degree (25 ℃, 100g, 5s)	0.1mm	T0604-2000	83
Softening point	℃	T0606-2000	46.9
				Ductility (5cm/min, 5 ℃ C.)	cm	T0605-1993	74
Dynamic viscosity (135 ℃ C.)	CP	T0625-2011	400

6) The mineral aggregate is composed of coarse aggregate, fine aggregate and mineral powder (wherein the maximum particle size of the coarse aggregate is 13.2mm), the using amount of the mineral powder is 3-7% of the mass of the mineral aggregate, the mineral component of the coarse aggregate and the mineral powder is limestone, and all indexes meet the condition requirements listed in table 4.

The indexes in Table 4 are the gross volume relative density and apparent relative density of each material measured by screening out each grade of aggregate according to the test method in Highway engineering aggregate test Specification JTG E42-2005.

TABLE 4 physical index tables for coarse aggregate, fine aggregate and mineral powder

In this example, the mineral aggregate was graded based on an AC-13 ii semi-dense type, and a medium design porosity was used. When in design, the dosage of coarse aggregates near the maximum nominal particle size of the aggregates is reduced (the maximum nominal particle size of the aggregates is 13.2mm), and the dosage of fine aggregates with the particle size of less than 0.6mm is reduced, so that more aggregates with medium particle size are obtained; the usage amount of the mineral powder is 3-7%, and an s-type grading curve is formed. The primary classification of the mineral aggregate is shown in table 5, while ensuring high temperature performance while simultaneously achieving low temperature cracking resistance.

TABLE 5 Primary separation grading table for mineral aggregate

Mesh size/mm	16	13.2	9.5	4.75	2.36	1.18	0.6	0.3	0.15
										By percent/%)	100	95	72	43	30	22	15	11	8

In the embodiment, the asphalt mixture consists of road petroleum asphalt and mineral aggregate; the viscosity reducer, the catalytic cracking rubber powder and the organic solvent form a cold paving solvent; the cold-paving solvent is adopted to modify the asphalt mixture, and the modifier with excellent performance is added in the modification, so that the variety of the additive is reduced, and the cold-paving performance and the storage time of the asphalt mixture are improved; the viscosity reducer enables the modified asphalt to reach a flowing state at normal temperature, and cold paving of the mixture is realized; meanwhile, the addition of the waste catalytic cracking rubber powder reduces the consumption of asphalt, thereby reducing the cost of asphalt mixture, recycling waste, saving energy and protecting environment.

In the embodiment, the viscosity reducer and the catalytic cracking rubber powder are added in the cold-paving solvent, so that the weight of the road petroleum asphalt is reduced, the weight ratio of the organic solvent to the road petroleum asphalt reaches 20-30%, the proportion of the organic solvent is improved, the construction workability can be improved due to the higher usage amount of the organic solvent, the volatilization of the organic solvent in the mixture can be avoided, the storage property of the cold-paving modified asphalt mixture is improved, the resource waste and the environmental pollution are reduced, and the road operation cost can be reduced.

Example 5

In this example, the cold-laid modified asphalt mixture was prepared using the raw material mix provided in example 1. Specifically, 0.394 parts of viscosity reducer, 1.313 parts of petroleum resin, 2.625 parts of catalytic cracking rubber powder, 7.876 parts of organic solvent, 26.254 parts of road petroleum asphalt and 961.538 parts of mineral aggregate.

In this example, the weight of the ore fines was 3% of the weight of the ore charge.

In this embodiment, the preparation method of the cold-laid modified asphalt mixture includes the following steps:

1) adding catalytic cracking rubber powder at a constant speed when the temperature of the road petroleum asphalt reaches about 175 ℃, and simultaneously starting timing when the temperature of the asphalt reaches 175 ℃, and uniformly stirring for 75min by using a stirrer;

2) when the stirring time is 75min, adding the viscosity reducer until the viscosity reducer is completely dissolved, then adding the petroleum resin, and uniformly stirring for 12min by using a stirrer to prepare the composite modified asphalt; the total modification time is 87 min;

3) cooling the prepared composite modified asphalt to about 100 ℃, adding an organic solvent, and rapidly and uniformly stirring for 20min by using a glass rod or a stirrer; preparing a cold-laid composite modified asphalt binder;

4) pouring the proportioned normal-temperature aggregates (coarse aggregates and fine aggregates) into a stirring pot which is kept at 50 ℃, starting the stirring for 90s, pouring the normal-temperature cold-laid composite modified asphalt binder, and stirring for 90 s; then mineral powder is poured into the mixture and mixed for 90 seconds to prepare the cold-paving type modified asphalt mixture.

Example 6

In this example, the cold-laid modified asphalt mixture was prepared using the raw material mix provided in example 2. Specifically, 0.441 part of viscosity reducer, 1.470 parts of petroleum resin, 2.939 parts of catalytic cracking rubber powder, 8.818 parts of organic solvent, 29.394 parts of road petroleum asphalt and 956.938 parts of mineral aggregate.

In this example, the weight of the ore fines is 5% of the weight of the ore charge.

1) adding catalytic cracking rubber powder at a constant speed when the temperature of the road petroleum asphalt reaches about 183 ℃, and simultaneously starting timing when the temperature of the asphalt reaches 183 ℃, and uniformly stirring for 55min by using a stirrer;

2) stirring for 55min, adding viscosity reducer until the viscosity reducer is completely dissolved, adding petroleum resin, and stirring with a stirrer for 15min to obtain composite modified asphalt; the total modification time is 70 min;

3) cooling the prepared composite modified asphalt to about 95 ℃, adding an organic solvent, and rapidly and uniformly stirring for 10min by using a glass rod or a stirrer; preparing a cold-laid composite modified asphalt binder;

4) pouring the proportioned normal-temperature aggregates (coarse aggregates and fine aggregates) into a stirring pot which is kept at 55 ℃, starting the stirring machine and stirring for 90s, then pouring the normal-temperature cold-laid composite modified asphalt binder and stirring for 90 s; then mineral powder is poured into the mixture and mixed for 90 seconds to prepare the cold-paving type modified asphalt mixture.

Example 7

In this example, the cold-laid modified asphalt mixture was prepared using the raw material mix provided in example 3. Specifically, 0.391 part of viscosity reducer, 1.303 parts of petroleum resin, 2.606 parts of catalytic cracking rubber powder, 7.819 parts of organic solvent, 26.064 parts of road petroleum asphalt and 961.816 parts of mineral aggregate.

In this example, the weight of the ore fines was 6% of the weight of the ore charge.

1) adding catalytic cracking rubber powder at a constant speed when the temperature of the road petroleum asphalt reaches about 190 ℃, and simultaneously starting timing when the temperature of the asphalt reaches 190 ℃, and uniformly stirring for 45min by using a stirrer;

2) stirring for 45min, adding viscosity reducer until the viscosity reducer is completely dissolved, adding petroleum resin, and uniformly stirring for 20min by using a stirrer to obtain composite modified asphalt, wherein the total modification time is 65 min;

3) cooling the prepared composite modified asphalt to about 90 ℃, adding an organic solvent, and rapidly and uniformly mixing for 15min by using a glass rod or a mixer; preparing a cold-laid composite modified asphalt binder;

4) pouring the proportioned normal-temperature aggregates (coarse aggregates and fine aggregates) into a stirring pot which is kept at the temperature of 60 ℃, starting the stirring for 90s, pouring the normal-temperature cold-laid composite modified asphalt binder, and stirring for 90 s; then mineral powder is poured into the mixture and mixed for 90 seconds to prepare the cold-paving type modified asphalt mixture.

Example 8

In this example, the cold-laid modified asphalt mixture was prepared using the raw material mix provided in example 4. Specifically, 0.420 part of viscosity reducer, 1.399 part of petroleum resin, 2.797 parts of catalytic cracking rubber powder, 5.595 parts of organic solvent, 27.974 parts of road petroleum asphalt and 961.816 parts of mineral aggregate.

In this example, the weight of the ore fines was 7% of the weight of the ore charge.

1) adding catalytic cracking rubber powder at a constant speed when the temperature of the road petroleum asphalt reaches about 200 ℃, and simultaneously starting timing when the temperature of the asphalt reaches 200 ℃, and uniformly stirring for 60min by using a stirrer;

2) stirring for 60min, adding viscosity reducer until the viscosity reducer is completely dissolved, adding petroleum resin, and stirring with a stirrer for 15min to obtain composite modified asphalt; the total modification time is 75 min;

3) cooling the prepared composite modified asphalt to about 85 ℃, adding an organic solvent, and rapidly and uniformly mixing for 15min by using a glass rod or a mixer; preparing a cold-laid composite modified asphalt binder;

The pavement performance of the common asphalt mixture after paving is emphasized, and the initial strength, the looseness, the compactibility, the forming strength, the water stability and the like of the cold-paved asphalt mixture need to be balanced during preparation due to the strength forming characteristics and the long-term storage characteristics of the cold-paved asphalt mixture; the preparation difficulty is to balance the looseness and compactibility of the mixture, to pave and level the road in a lower temperature environment, to have higher strength after paving and compacting, to bear the driving and load, and to avoid the phenomena of falling and falling particles.

Therefore, in order to illustrate the performance superiority of the cold-paving type modified asphalt mixture prepared by the invention, a series of performance verification tests are carried out by taking the cold-paving type modified asphalt mixtures with different proportions prepared by the preparation method as targets.

Test 1 initial Marshall Strength of Cold-laid modified asphalt mixture

Experimental groups: cold-laid modified asphalt mixture prepared according to the mixture ratio listed in examples 1-4

The test process comprises the following steps: the mixed cold-paving modified asphalt mixture is shoveled into an unheated test mold, inserted and tamped clockwise 15 times along the edge by a slotting cutter and 10 times inside, and according to the compacting and forming method of the hot-mixing asphalt mixture, the front and the back of the hot-paving modified asphalt mixture are compacted 75 times respectively at room temperature to prepare a standard Marshall test piece. And (3) after demolding, placing the sample in a constant-temperature water bath box at 25 ℃ for heat preservation for 30-40 min, measuring the Marshall stability of the test piece, namely the initial stability, and combining the research of 'storage type cold paving asphalt mixture' published in 2001 of rhododendron of Changan university and the research of most scholars, wherein the recommended initial strength value is 2.5KN-3.0 KN. The results of the measurements are shown in Table 6.

As can be seen from Table 6, the Marshall initial stability of the cold-paving type modified asphalt mixture obtained by the materials, the proportion and the preparation method provided by the invention is 2.82-3.65 KN. Compared with the recommended value, the cold-paving type modified asphalt mixture obtained by the invention has higher initial stability, good stability and easy cold paving construction.

TABLE 6 test results of Cold-spread modified asphalt mixture

Test 2 looseness and compactibility of Cold-spread modified asphalt mixture

The test process comprises the following steps: and (3) forming a test piece of the cold-laid modified asphalt mixture before and after aging by adopting a static pressure method, testing the uniaxial unconfined compressive strength of the formed test piece, and judging the looseness and the compactibility according to the test value. The test values are shown in Table 6.

As can be seen from Table 6, the unconfined compressive strength before aging is 90.71-116.49 KPa; and the value of the unconfined compressive strength after aging is 920.68-1604 KPa. According to the research on storage type cold-paving asphalt mixture published in 2001 of rhododendron of Changan university, the unconfined compressive strength values of cold-paving materials before and after aging are respectively less than 200KPa and 1000 KPa. Therefore, the cold-paving type modified asphalt mixture prepared by the invention has good balance of the looseness and the compaction performance.

Test 3 Water stability of Cold-spread modified asphalt mixture

The test process comprises the following steps: the water stability of the cold-laid modified asphalt mixture was evaluated by the water immersion marshall test. Specifically, Marshall's test pieces prepared as a standard were subjected to water bath at 25 ℃ for 30min and 48 hours, and the residual stability values were measured. The test results are shown in table 6.

As is clear from Table 6, the Marshall residual stability in water immersion was 83.3 to 89%. The residual stability value should be no less than 75% based on the water stability requirements for the modified asphalt in the asphalt test protocol. Therefore, the cold-paving type modified asphalt mixture prepared by the invention has good water stability.

Test 4 Molding Strength of Cold-spread modified asphalt mixture

The test process comprises the following steps: and (4) carrying out a forming strength test by adopting an oven heating method. Specifically, the cold paving material is paved to be 5cm thick, placed in a drying oven at the temperature of 110 ℃ for heat preservation for 24 hours to promote the volatilization of the organic solvent in the mixture, then formed according to the method of hot-mixing the asphalt mixture, and kept in a water tank at the temperature of 60 ℃ for 30min to test the Marshall value. The test results are shown in Table 6.

As can be seen from Table 6, the Marshall stability of the cold-paving type modified asphalt mixture obtained by the materials, the mixture ratio and the preparation method provided by the invention is 10.53-18.91 KN.

According to the conclusion of a plurality of relevant research experiences, the Marshall stability value of the cold-paving solvent modified asphalt material is not less than 4 KN. Compared with the cold-laid modified asphalt mixture prepared by the invention, the cold-laid modified asphalt mixture has better strength.

Test 5 dynamic stability value

Experimental groups: cold-laid modified asphalt mixture prepared according to the mixture ratio listed in example 1

The test process comprises the following steps: and (4) carrying out a rutting test by adopting an accelerated forming method. Specifically, the cold-laid modified asphalt mixture is laid and then placed in a forced ventilation oven at 110 ℃ for heat preservation for 24 hours, and after heat preservation, a rutting test is carried out according to the test method of the hot-mixed asphalt mixture.

The average value of the dynamic stability of the sample test value is 2048 times/mm, and the requirement of the technical specification JTG F40-2004 for the construction of the road asphalt pavement on the modified asphalt is met, wherein the average value of the dynamic stability of the sample test value is more than 1800 times/mm. The cold-laid modified asphalt mixture has enough high-temperature performance after the solvent is volatilized.

Example 6 maximum bend tensile Strain value

The test process comprises the following steps: and (4) evaluating the low-temperature performance by bending the trabeculae by referring to a hot-mixed asphalt mixture test. Specifically, the test piece is formed by cutting a track plate made of cold-laid modified asphalt mixture according to a specified size, and the cut trabecular test piece is stored indoors for 7 days to ensure that the solvent in the test piece is completely volatilized. The test was carried out after heat preservation for 45min in a thermostat at-10 ℃. The average value of the bending tensile strength of the test sample is 6.85MPa, the average value of the bending stiffness modulus of the test sample is 2714MPa, and the average value of the maximum bending tensile strain of each test piece is 3402 mu.

According to the requirements of technical specification JTG F40-2004 for road asphalt pavement construction on modified asphalt, the maximum bending-tensile strain value of the cold-laid asphalt mixture is not less than 2500 mu. Therefore, the maximum bending strain value of 3402 mu of the cold-paving type modified asphalt mixture prepared by the invention is larger than 2500 mu required in the specification. The cold-laid modified asphalt mixture has enough low-temperature cracking resistance.

Test 7 storage Properties

The cold-paving type modified asphalt mixture prepared by the invention belongs to a solvent type cold-paving asphalt mixture, and the strength is gradually formed after the cold-paving solvent is volatilized, so that the strength which accords with the road performance is finally achieved; the sealed storage of the solvent-based cold-laid asphalt mixture is of great importance to avoid the volatilization of the cold-laid solvent inside the mixture. During actual construction, road operation enterprises purchase and store cold-laid asphalt mixtures, but the cold-laid asphalt mixtures lose effectiveness after the storage time is exceeded, and the cold-laid asphalt mixtures need to be purchased again. Therefore, the construction requirement is prevented from being influenced by failure, and the storage performance is tested and verified.

The test process comprises the following steps: the cold-laid modified asphalt mixture was initially stored and after 4 months of storage, the initial strength, the loosening property, the compactibility, the molding strength and the water stability of the mixture were measured, and the test results are shown in table 7.

TABLE 7 comparison of values before and after storage of Cold-laid modified asphalt mixtures

From the test results in table 7, it can be seen that the cold-laid asphalt mixture has all the properties meeting the requirements after being stored for four months. In the storage period of four months, the cold-paving solvent in the cold-paving asphalt mixture is partially volatilized, and the test values of the initial strength and the looseness are improved to a certain degree compared with the test values before the storage, but still are within the recommended value range. Therefore, the cold-paving type modified asphalt mixture modified by the cold-paving solvent has a longer storage life.

According to statistics, the storage time of the cold-laid asphalt mixture at the present stage is mostly less than 3 months, and after the cold-laid modified asphalt mixture is stored for 4 months, all performance evaluation indexes of the cold-laid modified asphalt mixture can meet the standard requirements, and the storage time is long. The cold-laid modified asphalt mixture has longer storage time, so that not only can the resource waste and the environmental pollution be reduced, but also the road operation cost can be reduced.

In conclusion, the cold-paving type modified asphalt mixture provided by the invention belongs to a solvent type cold-paving asphalt mixture, the cold-paving solvent is adopted to modify the asphalt mixture, the average value of the maximum bending strain at-10 ℃ is 3402 mu, the average value of the dynamic stability at high temperature is 2048 times/mm, and when the road is constructed, the road can be paved and leveled in a low-temperature environment without adopting a heating construction process, the temperature dependence is low, the construction environmental pollution is low, the construction is quick and simple, and the traffic is not required to be completely closed; meanwhile, the coating has higher strength after being paved and compacted, the storage time is as long as 4 months, and the coating still has enough high-temperature performance and low-temperature cracking resistance after the organic solvent is volatilized, can bear driving and load, and does not fall off or fall off particles.

Claims

1. A cold-laid modified asphalt mixture is characterized in that: the cold-paving type modified asphalt mixture comprises a cold-paving solvent, petroleum resin, road petroleum asphalt and mineral aggregate; the cold paving solvent comprises a viscosity reducer, catalytic pyrolysis rubber powder and an organic solvent; the mineral aggregate is composed of coarse aggregate, fine aggregate and mineral powder; the viscosity reducer is prepared from 0.39-0.42 part by weight of petroleum resin 1.30-1.40 parts by weight, 2.61-2.94 parts by weight of catalytic cracking rubber powder, 5.59-8.82 parts by weight of organic solvent, 26.06-29.39 parts by weight of road petroleum asphalt and 956.94-961.82 parts by weight of mineral aggregate.

2. The cold-laid modified asphalt mixture according to claim 1, wherein: the weight of the mineral powder is 3-7% of the weight of the mineral aggregate.

3. The cold-laid modified asphalt mixture according to claim 2, wherein: the mineral components of the coarse aggregate, the fine aggregate and the mineral powder are limestone, and all indexes meet the following requirements:

4. a method for preparing a cold-laid modified asphalt mixture according to any one of claims 1 to 3, characterized in that: the preparation method comprises the following steps:

5. The method for preparing a cold-laid modified asphalt mixture according to claim 4, wherein the method comprises the following steps: in the step 4), the Marshall initial stability value of the cold-laid modified asphalt mixture is 2.82-3.65 KN, and the Marshall forming stability value is 10.53-18.91 KN; the average bending tensile strength is 6.85 MPa; the average bending stiffness modulus is 2714 MPa; the maximum bending strain averaged 3402 μ.

6. When the cold-paving type modified asphalt mixture as claimed in any one of claims 1 to 3 is used for cold paving, the cold paving solvent improves the cold paving performance of the cold-paving type modified asphalt mixture.

7. A cold-paving solvent which prolongs the shelf life of a cold-paving modified asphalt mixture when the cold-paving modified asphalt mixture as defined in any one of claims 1 to 3 is used for cold paving.