CN113462176A

CN113462176A - Warm-mixed flame-retardant SMA asphalt mixture, and preparation method, application and construction method thereof

Info

Publication number: CN113462176A
Application number: CN202110753907.5A
Authority: CN
Inventors: 王丽丽; 高振华; 仲光昇; 梁忠善; 沈剑
Original assignee: Suzhou Sanchuang Pavement Engineering Co ltd
Current assignee: Suzhou Sanchuang Pavement Engineering Co ltd
Priority date: 2021-07-03
Filing date: 2021-07-03
Publication date: 2021-10-01

Abstract

The application relates to the technical field of asphalt road construction, and particularly discloses a warm-mixed flame-retardant SMA asphalt mixture, and a preparation method, application and construction method thereof. A warm-mix flame-retardant SMA asphalt mixture comprises SBS modified asphalt, aggregate, fiber, Sasobit warm-mix agent and flame retardant; the preparation method comprises the following steps: s1, heating and drying the coarse aggregate, the fine aggregate and the SBS modified asphalt; s2, adding the SBS asphalt mixture into the mixing pot and uniformly stirring; and S3, placing the mixture obtained in the S2 into an oven for forming. The construction method of the warm-mix flame-retardant SMA asphalt mixture comprises the steps of paving, initial pressing, re-pressing, final pressing and the like. The warm-mix flame-retardant SMA asphalt mixture can be used for paving tunnels and road surfaces, has excellent high-temperature anti-rutting performance, low-temperature anti-cracking performance and water stability, and has road performance superior to that of a hot-mix mixture; in addition, the warm-mixed flame-retardant SMA mixture in the preparation method and the construction method can reduce the temperature of mixing, paving and compacting by about 20 ℃.

Description

Warm-mixed flame-retardant SMA asphalt mixture, and preparation method, application and construction method thereof

Technical Field

The application relates to the technical field of asphalt road construction, in particular to a warm-mixed flame-retardant SMA asphalt mixture, and a preparation method, application and construction method thereof.

Background

In recent years, with the rapid development of road construction in China, the requirements of traffic and weather conditions on the service performance of the highway surface are higher and higher, and on one hand, the damage of vehicles to the road surface is aggravated by the heavy load, overload and canalized traffic of vehicles running on the highway; on the other hand, the temperature difference of most of China in four seasons is greatly changed, and the asphalt pavement is subjected to various climate condition changes; there is an increasing demand for high quality road asphalt. Therefore, modifying asphalt is a conventional method for improving the quality of asphalt.

The modified asphalt is prepared by adding modifiers such as rubber, resin, high molecular polymer or other fillers into asphalt, so that the high-temperature performance, the low-temperature performance, the durability, the aging resistance and other performances of the asphalt are improved, and the service performance of an asphalt pavement is improved. The SMA asphalt mixture has the characteristics of high-temperature anti-rutting capability, low-temperature anti-cracking performance, water stability and the like, so that the SMA asphalt mixture is rapidly developed in China.

But the SMA asphalt mixture construction temperature is high, the aggregate heating temperature is between 180 ℃ and 190 ℃, and the discharge temperature needs to be controlled between 175 ℃ and 185 ℃. Because the construction temperature is high, a large amount of asphalt smoke is generated in the construction process, the environmental pollution is heavy, the energy consumption is serious and the like; if the construction is carried out in the north, the temperature difference between the construction temperature and the outside is large, so that the temperature of the SMA asphalt mixture is quickly reduced, and the compaction of the SMA asphalt mixture is not facilitated.

In view of the above-mentioned related technologies, the inventors consider that the problem of high construction temperature of SMA asphalt mixture limits its development and use.

Disclosure of Invention

In order to reduce the construction temperature of the SMA asphalt mixture and improve the development and use of the SMA asphalt mixture, the application provides a warm-mixed flame-retardant SMA asphalt mixture, and a preparation method, application and construction method thereof.

In a first aspect, the application provides a warm-mix flame-retardant SMA asphalt mixture, which adopts the following technical scheme:

the warm-mixed flame-retardant SMA asphalt mixture is characterized by being prepared from the following raw materials in parts by weight: 1000 parts of SBS modified asphalt, 58-64 parts of aggregate, 40 parts of fiber, 10-50 parts of Sasobit warm mixing agent and 500 parts of flame retardant.

By adopting the technical scheme, the Sasobit warm-mixing agent is a surfactant, the molecules of which consist of lipophilic groups and hydrophilic groups, the lipophilic groups are gathered due to the similar polarity in the aqueous solution, and the hydrophilic groups are dispersed into water, so that the uniformly dispersed surfactant micelle aqueous solution is formed. In the process of mixing the mixture, the Sasobit warm mixing agent and the asphalt are synchronously sprayed into the mixing pot. Under the mechanical stirring, a large amount of surfactant micelles are contacted with hot asphalt, water molecules on the peripheries of the micelles are rapidly evaporated and dissipated, and the lipophilic group is contacted with the asphalt; the residual water molecules which are not lost are combined with the hydrophilic groups of the surfactant, so that the fluidity of the asphalt mortar is improved, and the cohesive force of asphalt is reduced, so that the mixture is easy to compact. In addition, the asphalt is easy to ignite at high temperature due to the flammability of the asphalt, and the flame retardant can generate strong endothermic reaction at high temperature, so that the temperature of the surface of the asphalt is reduced, and the flame retardant effect is achieved.

Preferably, the aggregate comprises coarse aggregate, fine aggregate and limestone mineral powder, the coarse aggregate comprises 1# basalt and 2# basalt, the fine aggregate comprises 3# basalt and 4# basalt, and the proportion of the 1# basalt, the 2# basalt, the 3# basalt, the 4# basalt and the limestone mineral powder is 33: 43: 5: 10.5: 8.5, 33: 41: 5: 12.5: 8.5, 33: 39: 5: 145: 85.

By adopting the technical scheme, the aggregate is screened, so that the aggregate has a good particle shape, and the aggregate and the asphalt are better combined.

Preferably, the fibers include one or both of polyester fibers and flame retardant fibers.

By adopting the technical scheme, the polyester fiber has relatively high oil absorption rate, so that good asphalt absorption effect and flame retardant effect can be achieved under the combined action of the polyester fiber and the flame retardant fiber.

In a second aspect, the application provides a preparation method of a warm-mixed flame-retardant SMA asphalt mixture, which adopts the following technical scheme:

a preparation method of a warm-mixed flame-retardant SMA asphalt mixture comprises the following steps:

s1, heating the coarse aggregate and the fine aggregate to 135-145 ℃ and drying, heating the SBS modified asphalt to 165-175 ℃ without heating limestone mineral powder and drying;

s2, adding the coarse aggregates, the fine aggregates and the fibers in the step S1 into a mixing pot with the set temperature of 160 ℃ for dry mixing for 90S, adding SBS modified asphalt, Sasobit warm mixing agent, fire retardant and limestone mineral powder into the mixing pot for dry mixing for 90S, and uniformly stirring;

s3, placing the mixture in the S2 into an oven with the set temperature of 150-170 ℃ for forced ventilation for 2h, and then forming.

By adopting the technical scheme, when the warm-mixed flame-retardant SMA asphalt mixture is prepared, the heating temperature of the aggregate is reduced to a certain extent compared with that of the conventional preparation method, so that the construction difficulty is reduced, and the development and use of the SMA asphalt mixture are improved.

In a third aspect, the application provides a construction method of a warm-mixed flame-retardant SMA asphalt mixture, which adopts the following technical scheme:

a construction method of a warm-mixed flame-retardant SMA asphalt mixture comprises the following steps:

(1) paving: discharging and storing the SMA asphalt mixture uniformly stirred by the mixing pot, conveying the SMA asphalt mixture to a construction site, and paving the SMA asphalt mixture by adopting a paver at the full width at the temperature of not lower than 120 ℃;

(2) initial pressing: 2-3 times, selecting a 12-20t double-steel-wheel vibratory roller to perform vibratory compaction, wherein the compaction speed is 2-4km/h, and the initial temperature is not lower than 115 ℃;

(3) repressing: 1-2 times, adopting a 20-30t rubber-tyred roller, compacting at a speed of 3-6km/h and at a minimum temperature of not less than 100 ℃;

(4) final pressure: 1-2 times, selecting 10-18t double steel wheel road roller, and the static pressure light-collecting compaction speed can be 3-5km/h, and the surface temperature is not lower than 70 ℃.

By adopting the technical scheme, the formed pavement has good high-temperature anti-rutting capability, low-temperature anti-cracking performance and water stability.

Preferably, in the step (1), the delivery temperature of the SMA asphalt mixture is controlled to be 130-155 ℃, and the storage temperature is controlled to be 120-145 ℃.

By adopting the technical scheme, the phenomena of caking and segregation can not occur in the discharging and paving of the warm-mixed flame-retardant SMA mixture.

Preferably, in the step (2), the static pressure is adopted when severe shift occurs in the 1 st forward vibration rolling; and (3) adopting vibration pressing when severe pushing does not occur in the 1 st forward vibration rolling.

By adopting the technical scheme, because the static pressure is less than the vibration pressure, the road surface is protected by adopting a static pressure mode when the road surface is seriously pushed.

In a fourth aspect, the application provides an application of the warm-mixed flame-retardant SMA asphalt mixture, which adopts the following technical scheme:

the asphalt pavement is characterized by being paved by adopting the construction method.

The tunnel is characterized by being paved by the construction method.

By adopting the technical scheme, the application range of the warm-mixed flame-retardant SMA asphalt mixture is widened.

In summary, the present application has the following beneficial effects:

1. according to the method, the Sasobit warm mixing agent is added into the SBS modified asphalt, so that the viscosity of the SBS modified asphalt at the mixing temperature is reduced, the fluidity of asphalt mucilage is improved, and the cohesive force of asphalt mastic is reduced, so that the mixing and compacting resistance of the asphalt mixture is reduced, and the mixing and compacting effects of the warm-mixed asphalt mixture are improved;

2. according to the method, the aggregate grading and the optimal oilstone ratio of the warm-mixed flame-retardant SMA modified asphalt mixture can be accurately determined, and the influence of the aggregate grading and the fluctuation and change of the aggregate using amount on the construction quality of the warm-mixed flame-retardant SMA modified asphalt mixture is eliminated;

3. according to the application, the flame retardant is added into the SBS modified asphalt, and the flame retardant can generate strong endothermic reaction at high temperature, so that the temperature of the surface of the asphalt is reduced, and the flame retardant effect is achieved.

Detailed Description

The present application will be described in further detail with reference to test examples and examples.

Of the raw materials used in the experimental examples and examples: the SBS content of the SBS modified asphalt is 4.5 percent, the penetration degree of the SBS modified asphalt is 48mm, the ductility is 28.6cm, and the softening point is 89 ℃; the mineral aggregate mainly comprises coarse aggregate, fine aggregate and mineral powder. The coarse aggregate comprises 1# basalt with the size of 10-15mm and 2# basalt with the size of 5-10mm, wherein the surface relative density of the 1# basalt is 2.931, and the surface relative density of the 2# basalt is 2.936; the fine aggregate comprises 3# basalt with the size of 3-5mm and 4# basalt with the size of 0-3mm, wherein the surface relative density of the 3# basalt is 2.935, and the surface relative density of the 4# basalt is 2.854; the mineral powder is limestone mineral powder with the size of 0-0.6mm, and the water content is 0.6%; wood fibers were purchased from Hebei Hemiguang mineral products, Inc.; polyester fibers were purchased from engineering materials, inc. of leuw city; flame retardant fibers were purchased from tai an hao pine fiber ltd; the Sasobit warm mixing agent is purchased from Jiangsu ideal world new materials Co.Ltd; the flame retardant is purchased from flame retardant materials of combined fertilizer and Zhongke department, Inc.

Test examples 1 to 3

As shown in table 1, the main difference between test examples 1-3 is the different gradation of the aggregates in the SMA asphalt mix. Wherein the ratio of the aggregate in test example 1 (1# basalt: 2# basalt: 3# basalt: 4# basalt: limestone mineral powder) is 33: 43: 5: 10.5: 8.5; the aggregate of test example 2 was in a ratio of 33: 41: 5: 12.5: 8.5; the aggregate of test example 3 was in a ratio of 33: 39: 5: 145: 8.5.

test examples 1-3 were primarily intended to determine the design grading of SMA asphalt mix aggregates.

The following detailed description is given by taking test example 1 as an example, and the specific formula of the raw materials is as follows: 1000Kg of SBS modified asphalt, 19.8Kg of 1# basalt, 25.8Kg of 2# basalt, 3Kg of 3# basalt, 6.3Kg of 4# basalt, 5.1Kg of limestone mineral powder and 32.78Kg of wood fiber.

The preparation method of the SMA asphalt mixture of test example 1 was as follows:

s1, heating the coarse aggregate and the fine aggregate to 160 ℃ and drying, heating the SBS modified asphalt to 175 ℃ without heating the mineral powder and drying;

s2, adding the coarse aggregates, the fine aggregates and the wood fibers in the step S1 into a stirring pot with the temperature set at 160 ℃ for dry stirring for 90S, adding SBS modified asphalt and limestone mineral powder into the stirring pot for dry stirring for 90S, and uniformly stirring;

and S3, placing the mixture in the S2 into an oven with the temperature of 170 ℃ for forced ventilation for 2h, and then molding.

TABLE 1 compounding ratio of each raw material in test examples 1-3

The mineral composition (JTG F40) in test examples 1-3 obtained using the above starting materials is shown in Table 2.

TABLE 2 graduation of mineral aggregates in SMA asphalt mixtures

The SMA asphalt mixtures obtained in the test examples 1 to 3 with the same weight were used as test samples 1 to 3, Marshall test pieces were respectively prepared, and the test samples 1 to 3 were subjected to a standard Marshall test, wherein the test sample diameter was 101.6mm, the cross-shaped test samples were measured in 4 directions with a height of 63.5mm, and the loading speed was 50 mm/min. The results are shown in Table 3.

Table 3 marshall test results of design grading

As can be seen from table 3, each item of test sample 1 satisfies the technical requirements, but the effective asphalt saturation VFA thereof is slightly small; each index of the test sample 2 meets the technical requirement, and the porosity is 3.9 percent and is close to the target porosity of 4.0 percent; the void ratio and the mineral aggregate void ratio of the test 3 are both small; therefore, test example 2 was used as a design gradation.

Test examples 4 to 6

As shown in Table 4, examples 4 to 6 were substantially the same as example 2, except that the asphalt-to-stone ratios of the SMA asphalt mixtures were different. Wherein: the oilstone ratio of test example 2 was: 6.0%, the oilstone ratio of test example 4 was: 5.8%, the oilstone ratio of test example 5 was: 6.2%, the oilstone ratio of test example 6 was: 6.4 percent.

Test examples 2, 4-6 were primarily intended to determine the optimum oilstone ratio for SMA asphalt mixes.

The following is a description by taking test example 4 as an example, and the specific formula of the raw materials is as follows: 1000Kg of SBS modified asphalt, 19.14Kg of 1# basalt, 23.78Kg of 2# basalt, 2.9Kg of 3# basalt, 7.25Kg of 4# basalt, 4.93Kg of limestone mineral powder and 32.72Kg of wood fiber.

TABLE 4 compounding ratio of each raw material in test examples 4 to 6

Test comparative example 1

Experimental comparative example 1 is different from experimental example 4 in that the oilstone ratio of experimental comparative example 1 is 5.6%.

Marshall test pieces were respectively prepared by using the same weight of the SMA asphalt mixture obtained in test examples 4 to 6 as test samples 4 to 6 and the same weight of the SMA asphalt mixture obtained in test comparative example 1 as test comparative sample 1 as the test samples. The results of Marshall's tests were performed on test samples 2, 4-6 and test control sample 1 and are shown in Table 5.

TABLE 5 Marshall test results for SMA oilstone ratio

As can be seen from Table 5, when the asphalt-stone ratio is 5.6%, the effective asphalt saturation VFA of the SMA asphalt mixture is only 72%, and the technical requirements are not met; when the oilstone ratio is 5.8%, all indexes of the SMA asphalt mixture meet the technical requirements, but the porosity is larger than the target porosity of 4.0%; when the oilstone ratio is 6.0%, all indexes of the SMA asphalt mixture meet the technical requirements, and the porosity is close to the target porosity; when the oil-stone ratio is 6.2% and 6.4%, various indexes of the SMA asphalt mixture meet the technical requirements, but the porosity is smaller. Therefore, test example 2 was selected to design the optimum oilstone ratio for the graded SMA asphalt mix.

Design oilstone ratio verification

For test sample 2 and test samples 4-6, the number of excessive free asphalt (or asphalt mastic) precipitated from the SMA asphalt mixture at 185 ℃ and the mass loss rate of the SMA asphalt mixture after rotating impact in a los Angeles tester were respectively determined by a Schlumberger asphalt leakage test. The asphalt bleed test results and fly-off test results for SMA at the design oilstone ratio are shown in fig. 6.

TABLE 6 results of the leakage test and the scattering test of the SMA asphalt mixture

As can be seen from Table 6, the leakage loss of the SMA asphalt mixtures with different oilstone ratios is less than 1.5%; the scattering loss of the scattering mixture of the SMA asphalt mixtures with different oilstone ratios is more than 2.5 percent; therefore, the test sample 2 and the test samples 4-6 both accord with the range of the oil-stone ratio, namely the SMA asphalt mixture with the oil-stone ratio ranging from 5.8% to 6.4% accords with the range of the oil-stone ratio.

Test examples 7 to 11

As shown in Table 7, the main difference between the experimental examples 7-11 is the difference between the fibers in the formulation, wherein the oil-stone ratio is 6.0% and the fibers are 0.4% by weight of the SMA asphalt mixture.

Test examples 7-11 were primarily intended to determine the best fiber formulation.

The following is a description of test example 7, which was prepared according to the following specific formulation: 1000Kg of SBS modified asphalt, 19.8Kg of 1# basalt, 24.6Kg of 2# basalt, 3Kg of 3# basalt, 7.5Kg of 4# basalt, 5.1Kg of limestone mineral powder and 43.71Kg of polyester fiber.

TABLE 7 compounding ratios of respective raw materials in test examples 7 to 11

The SMA asphalt mixtures obtained in test examples 2 and 7 to 11 were used in the same weight as test samples 2 and 7 to 11 to prepare leak test pieces, respectively, and the test samples 2 and 7 to 11 were subjected to the scherrenberg leak test at a test temperature of 185 ℃ for 1 hour, and the results are shown in table 8.

TABLE 8 leak test results for fibers in SMA asphalt mixtures

As can be seen from table 8, according to the technical requirements, the loss of the SMA leak test using wood fibers should not be greater than 0.1%, so the test sample 2 cannot meet the technical requirements of the leak test. In order to achieve good asphalt absorption effect and reduce the total consumption of the fibers, polyester fibers with slightly larger oil absorption rate than wood fibers are adopted as the compounding object of the flame-retardant fibers.

The test samples 7-11 were tested for flame retardant performance of SMA according to GB/T29051-.

TABLE 9 flame retardancy test results of composite fiber in SMA asphalt mixture

Combining table 8 and table 9, after the flame retardancy and leakage performance of SMA are balanced, the optimal mixture ratio of the composite fiber is 0.1% polyester fiber + 0.3% flame retardant fiber, i.e. test 10 is the optimal test sample.

Examples 1 to 5

As shown in Table 10, the main difference between examples 1-5 is the amount of Sasobit warm-mix in the formulation.

The following is given by way of example 1, and the specific formulation for the preparation is: 1000Kg of SBS modified asphalt, 19.8Kg of 1# basalt, 24.6Kg of 2# basalt, 3Kg of 3# basalt, 7.5Kg of 4# basalt, 5.1Kg of limestone mineral powder, 10.93Kg of polyester fiber, 32.78Kg of flame retardant fiber and 10Kg of Sasobit warm mixing agent.

The sample preparation method of example 1 is as follows:

s1, heating the coarse aggregate and the fine aggregate to 135 ℃ for drying, heating the modified asphalt to 165 ℃ without heating the mineral powder;

s2, adding the coarse aggregates, the fine aggregates and the fibers in the step S1 into a stirring pot with the temperature set at 160 ℃ for dry stirring for 90S, adding the modified asphalt and the mineral powder into the stirring pot for dry stirring for 90S, and uniformly stirring;

and S3, placing the mixture in the S2 into an oven with the set temperature of 150 ℃ for forced ventilation for 2h, and then molding.

TABLE 10 proportions of the respective raw materials in examples 1 to 5

Example 6

The present example is different from test example 10 in the preparation method, and example 6 is prepared by the following steps:

s1, heating the coarse aggregate and the fine aggregate to 145 ℃ for drying, heating the modified asphalt to 175 ℃ without heating the mineral powder;

Comparative example 1

Test example 10 was used as comparative example 1.

Performance detection

The same weight of the SMA asphalt mixtures obtained in examples 1 to 6 was used as samples 1 to 6, and the same weight of the SMA asphalt mixture obtained in comparative example 1 was used as control 1. The samples 1-6 and the control sample 1 are tested according to the test method T0736 in JTGE20, and the rubbing and compacting effects of the road roller load on the road surface are simulated by adopting the vertical pressure of 600kPa, the rotating and compacting angle of 126 and the rotating speed of 30r/min under the conditions that the rotating and compacting temperature is 145 ℃ and 150 ℃. Each group of test pieces adopts 2 kinds of rotary compaction times respectively: 100 times and 200 times (100 compaction times are used for SMA design index test, and 200 compaction times are used for SMA compaction characteristic calculation). The bulk density of the hot-mixed warm-mixed SMA test piece was measured using T0705 (dry method) in JTGE20 after compaction molding, demolding and cooling, and the bulk index of the SMA test piece was calculated therefrom, with the results shown in Table 11.

TABLE 11 volume index of warm-mix SMA asphalt mixture

As can be seen from table 11, the Sasobit warm-mix agent reduces the viscosity of the SBS modified asphalt at the mixing temperature, improves the fluidity of the asphalt mastic, and reduces the cohesive force of the asphalt mastic, thereby reducing the mixing and compacting resistance of the asphalt mixture, and improving the mixing and compacting effect of the warm-mix asphalt mixture. The volume index of the warm-mixed SMA can reach the volume index of the hot-mixed SMA by adding 2 to 3 percent of Sasobit warm-mixing agent. When the amount of the Sasobit warm-mixing agent is 3%, the performance of the SMA asphalt mixture is better, i.e. sample 3 is the best embodiment.

Since the rotary compaction temperature has certain influence on the porosity after multiple times of compaction, when the rotary compaction temperature is too high, the compaction times are reduced, for example, when the compaction temperature is increased by 5-10 ℃, the compaction times can be reduced to 75 times.

Examples 7 to 11

As shown in Table 12, the main difference between examples 7-11 is the amount of flame retardant in the formulations.

The following is a description of test example 7, which was prepared according to the following specific formulation: 1000Kg of SBS modified asphalt, 19.8Kg of 1# basalt, 24.6Kg of 2# basalt, 3Kg of 3# basalt, 7.5Kg of 4# basalt, 5.1Kg of limestone mineral powder, 10.93Kg of polyester fiber, 32.78Kg of flame retardant fiber, 30Kg of Sasobit warm mixing agent and 100Kg of flame retardant.

TABLE 12 compounding ratios of respective raw materials in test examples 7 to 11

Performance detection

The test pieces 3 and 7 to 11 were subjected to the test of the flame retardancy of the SMA asphalt mixture using the same weight of the SMA asphalt mixtures obtained in example 3 and examples 7 to 11 as the test pieces 3 and 7 to 11, and the results are shown in Table 13.

TABLE 13 flame retardancy test results of flame retardants in SMA asphalt mixture

According to the technical requirements that the oxygen index of an SMA asphalt mixture in flame-retardant asphalt concrete for roads (GB/T29051) is more than or equal to 23 percent and the smoke density grade is less than or equal to 75, in order to ensure good flame-retardant performance of asphalt, samples 10 and 11 meet the requirements, so that the consumption of a flame retardant is 40-50 percent.

The mix proportion of the warm-mix flame-retardant SMA asphalt mixture was verified, and the following test was performed on sample 11, with the test results shown in Table 14.

TABLE 14 pavement performance of warm mix flame retardant SMA asphalt mixture

Performance index	Unit of	Test results	Technical requirements
				Dynamic stability of rut test (60 ℃, 0.7MPa)	Sub/mm	12000	3000
Maximum bending strain of low-temperature bending property test	ue	5400	2500
				Residual stability ratio of immersion Marshall test	％	94.6	$o
Freezing and thawing cleavage testResidual strength ratio of	％	84.4	8o

As can be seen from Table 14, the pavement performance of the warm-mix flame-retardant SMA asphalt mixture meets the technical requirements of the specification, and has excellent high-temperature anti-rutting performance, low-temperature anti-cracking performance and water stability.

Example 12

The embodiment discloses a tunnel which is paved by adopting the warm-mixed flame-retardant SMA asphalt mixture in the embodiment 11.

The specific construction process comprises the following steps:

(1) paving: discharging and storing the SMA asphalt mixture uniformly stirred by the mixing pot, controlling the delivery temperature at 130 ℃ and the storage temperature at 120 ℃, transporting to a construction site, and paving by adopting a paver to realize full-width paving at the temperature of 120 ℃;

(2) initial pressing: 2 times, selecting a 12t double-steel-wheel vibratory roller to perform vibratory compaction, wherein the compaction speed is preferably 4km/h, and the initial temperature is 115 ℃; adopting static pressure when severe pushing occurs during the 1 st forward vibration rolling; when the serious pushing does not occur during the 1 st forward vibration rolling, adopting vibration pressing;

(3) repressing: 1 time, a 20t rubber-tyred roller is adopted, the compaction speed is preferably 5km/h, and the lowest temperature is 100 ℃;

(4) final pressure: 1 time, selecting a 10t double-steel-wheel road roller, wherein the static pressure light-collecting compaction speed can be 5km/h, and the surface temperature is 70 ℃.

Example 13

The embodiment also discloses an asphalt pavement which is paved by the warm-mixed flame-retardant SMA asphalt mixture of the embodiment 11.

The specific construction process comprises the following steps:

(1) paving: discharging and storing the SMA asphalt mixture uniformly stirred by the mixing pot, controlling the delivery temperature at 155 ℃ and the storage temperature at 145 ℃, transporting to a construction site, and paving by adopting a paver to realize full-width paving at the temperature of 130 ℃;

(2) initial pressing: 3 times, selecting a 20t double-steel-wheel vibratory roller to perform vibratory compaction, wherein the compaction speed is preferably 2km/h, and the initial temperature is 120 ℃; adopting static pressure when severe pushing occurs during the 1 st forward vibration rolling; when the serious pushing does not occur during the 1 st forward vibration rolling, adopting vibration pressing;

(3) repressing: 2 times, a 30t rubber-tyred roller is adopted, the compaction speed is preferably 3km/h, and the lowest temperature is 105 ℃;

(4) final pressure: and 2 times, selecting an 18t double-steel-wheel road roller, wherein the static pressure light-collecting compaction speed can be 3km/h, and the surface temperature is 75 ℃.

Examples 12 and 13 differ in the use of the SMA asphalt mix; after the technical performance of the SMA asphalt mixture is verified through tests, the technical requirements can be adjusted for special road sections with serious canalization traffic such as tunnel pavements, wherein the designed porosity can be adjusted to be 4.2%, the mineral aggregate clearance rate VMA and the mineral aggregate clearance rate VMA are not less than 16%, the saturation index can be widened to be 70% -85%, when the aggregate mixture performance meets the requirements, the coarse aggregate skeleton clearance rate VCAmix index is not required, and the asphalt loss in a leakage analysis test can be widened to be not more than 0.3%.

The present embodiment is only for explaining the present application, and it is not limited to the present application, and those skilled in the art can make modifications of the present embodiment without inventive contribution as needed after reading the present specification, but all of them are protected by patent law within the scope of the claims of the present application.

Claims

1. The warm-mixed flame-retardant SMA asphalt mixture is characterized by being prepared from the following raw materials in parts by weight: 1000 parts of SBS modified asphalt, 58-64 parts of aggregate, 40 parts of fiber, 10-50 parts of Sasobit warm mixing agent and 500 parts of flame retardant.

2. The warm-mixed flame-retardant SMA asphalt mixture according to claim 1, which is characterized in that: the aggregate comprises coarse aggregate, fine aggregate and limestone mineral powder, the coarse aggregate comprises 1# basalt and 2# basalt, the fine aggregate comprises 3# basalt and 4# basalt, and the proportion of the 1# basalt, the 2# basalt, the 3# basalt, the 4# basalt and the limestone mineral powder is 33: 43: 5: 10.5: 8.5, 33: 41: 5: 12.5: 8.5, 33: 39: 5: 145: 85.

3. The warm-mixed flame-retardant SMA asphalt mixture according to claim 1, which is characterized in that: the fibers include one or both of polyester fibers and flame retardant fibers.

4. The preparation method of the warm-mixed flame-retardant SMA asphalt mixture according to any one of claims 1 to 3, which is characterized in that: the method comprises the following steps:

5. The construction method of the warm-mixed flame-retardant SMA asphalt mixture according to claim 4, characterized in that: the method comprises the following steps:

6. The construction method of the warm-mixed flame-retardant SMA asphalt mixture according to claim 5, characterized in that: in the step (1), the delivery temperature of the SMA asphalt mixture is controlled to be 130-155 ℃, and the storage temperature is controlled to be 120-145 ℃.

7. The construction method of the warm-mixed flame-retardant SMA asphalt mixture according to claim 5, characterized in that: in the step (2), adopting static pressure when severe pushing occurs during the 1 st forward vibration rolling; and (3) adopting vibration pressing when severe pushing does not occur in the 1 st forward vibration rolling.

8. An asphalt pavement characterized by being paved by the method according to any one of claims 5 to 7.

9. A tunnel, characterized in that it is paved by the method of any one of claims 5 to 7.