CN111960730A - Foamed asphalt warm-mix mixture and preparation method thereof - Google Patents

Abstract

The application discloses a foamed asphalt warm-mix mixture and a preparation method thereof, belonging to the field of asphalt mixtures. The preparation method comprises the following steps: heating 1-6 parts of matrix asphalt to 140-160 ℃, and adding water containing a foaming agent and a stabilizing agent, wherein the mass of the water is 0.8-1.5% of that of the asphalt, so as to obtain foamed asphalt; b. mixing 10-40 parts of waste cement concrete recycled aggregate and 20-80 parts of old asphalt pavement material, and stirring at 95-130 ℃ for 40-90 s; then adding the foamed asphalt, and stirring at the temperature of 130-140 ℃ for 40-90 s; finally, 2-20 parts of mineral powder is added and mixed for 40-90s at the temperature of 95-130 ℃. The application can greatly reduce the discharge amount of harmful gas and dust, simultaneously reduce the energy consumption in the production process, also can reduce the aging of asphalt cement in the production process, and improve the road performance of the mixture.

Description

Foamed asphalt warm-mix mixture and preparation method thereof

Technical Field

The application relates to the field of asphalt mixtures, in particular to a foamed asphalt warm-mix mixture and a preparation method thereof.

Background

At present, more than 90% of road engineering construction of countries in the world adopts asphalt pavements paved by asphalt mixtures. The asphalt mixture can be divided into two types of hot-mix asphalt mixture and cold-mix asphalt mixture according to the manufacturing process. The hot-mix asphalt mixture has good road performance, but consumes a large amount of fuel in the production and construction process, discharges a large amount of harmful gas and dust, seriously pollutes the environment and causes harm to the health of constructors. The cold-mix asphalt mixture has the advantages of environmental protection and energy conservation because of no heating, but the pavement performance is not high, and the cold-mix asphalt mixture is difficult to compare with the hot-mix asphalt mixture. Therefore, the introduction of the asphalt warm mixing technology can well solve the technical problems.

The warm-mix asphalt mixture is a novel energy-saving environment-friendly material which reduces the viscosity of asphalt through a certain technical measure, so that the mixing temperature of the asphalt mixture is between the mixing temperature of the hot-mix asphalt mixture and the cold-mix asphalt mixture, and the performance of the warm-mix asphalt mixture reaches or approaches to that of the hot-mix asphalt mixture. The existing warm mix asphalt technology mainly comprises an asphalt-mineral method, an asphalt foam method, an organic additive method, a surfactant method and the like. Wherein, the foamed asphalt is prepared by adding water into high-temperature asphalt to form steam bubbles, so that the asphalt has expanded volume and reduced viscosity, and the aim of easy mixing is fulfilled.

Along with the continuous development of the human society and the continuous expansion of the urban construction scale, the exhaustion of energy and the deterioration of the environment become serious threats in front of human beings, and the development of circular economy, the sustainable development of roads, energy conservation and emission reduction are more and more paid more attention by people. A large amount of construction waste is generated in the construction industry nowadays, most of the construction waste is directly transported to the suburbs without being treated and is treated in an open-air stacking or landfill mode, and a large amount of cost is required in the treatment process; meanwhile, dust and sand are easy to be scattered in the process of clearing and stacking the construction waste, and serious environmental pollution can be caused. If the garbage can be regenerated and applied to an asphalt pavement structure, the energy exhaustion can be greatly relieved, and the problem of environmental deterioration is effectively solved. For example, recycling of old asphalt pavement materials and resource utilization of construction waste are important measures for practically implementing resource recycling. In conclusion, if the construction waste can be regenerated and applied to the foamed asphalt warm-mix mixture, the requirements of national development can be met, and the application prospect is wide.

Disclosure of Invention

Aiming at the defects in the prior art, the application aims to provide the foamed asphalt warm-mix mixture, which achieves the purposes of saving resources and protecting the environment by utilizing the construction industry garbage as the aggregate.

The second purpose of the application is to provide a preparation method of the foamed asphalt warm-mix mixture, and the purposes of reducing harmful gas and dust generation and reducing the production cost of the asphalt mixture are achieved through a warm-mix technology.

The technical purpose of the application is realized by the following technical scheme:

the foamed asphalt warm-mix mixture comprises the following components in parts by weight:

1-6 parts of foamed asphalt;

10-40 parts of waste cement concrete recycled aggregate;

20-80 parts of old asphalt pavement material;

2-20 parts of mineral powder

0.01-0.05 part of foaming agent;

0.01-0.05 part of stabilizer.

Through adopting above-mentioned technical scheme, the waste cement concrete that this application adopted a large amount of productions in the building work progress and the old bituminous paving material who produces a large amount in old road surface transformation, maintenance process is as gathering materials, and waste cement concrete and old bituminous paving material's use amount is big in this application foam asphalt mixture in addition, and energy saving that can furthest reduces environmental pollution.

The application strictly limits the proportion of foamed asphalt to aggregate (waste cement concrete and old asphalt pavement materials), because too much asphalt content can produce adverse effect to the mixture strength, and too much asphalt neither wraps up in fine aggregate nor wraps up in coarse aggregate, plays the effect of lubricant on the contrary and leads to the reduction of foamed asphalt mixture strength and stability.

The foaming agent is added into the foamed asphalt mixture, so that the foaming performance of the matrix asphalt can be improved, the expansion rate is improved, and the half-life period is prolonged. The larger the volume expansion factor of the asphalt is, the better the workability of construction is, and the higher the dispersion uniformity of the foamed asphalt in the finally-formed mixture is. The longer the decay period, the slower the decay of the asphalt foam, and the longer the effective mixing time provided in the construction. Therefore, it is very necessary to increase the expansion rate and prolong the half-life of the foamed asphalt.

The consumption of the foamed asphalt in the foamed asphalt mixture is generally lower than that of the common hot-mix asphalt mixture, the consumption of the common asphalt can be reduced by 5-10%, and only part of large-particle-size aggregates in the foamed asphalt mixture is coated by the foamed asphalt. Therefore, the stability of the foamed asphalt mixture is affected to some extent due to the relatively small amount of binder and high porosity. According to the application, the stabilizer is added into the foamed asphalt mixture, so that the stability of the foamed asphalt mixture can be effectively improved, and the road performance can reach the best.

Preferably, the foamed asphalt warm mix comprises the following components in parts by weight:

2-5 parts of foamed asphalt;

15-35 parts of waste cement concrete recycled aggregate;

30-70 parts of old asphalt pavement material;

5-15 parts of mineral powder

0.02-0.04 part of foaming agent;

0.02-0.04 part of stabilizer.

Preferably, the matrix asphalt is Buton rock asphalt.

By adopting the technical scheme, the Buton rock asphalt has good anti-rutting capability, delays the generation of pavement ruts, and reduces the rutting depth and the occurrence of fatigue shear cracks; the paint has strong wetting property and high resistance to free oxidation radicals, and particularly has high adhesion to aggregate and high peeling resistance; the asphalt pavement has good high temperature resistance, aging resistance and weather resistance, the durability of the asphalt pavement is improved, and the aging speed of the asphalt is slowed down, so that the service life of the road is prolonged; the foaming performance is good, the expansion rate is high, the half-life period is long, and the mixing effect and the construction workability of the mixture are improved.

Preferably, the waste cement concrete recycled aggregate comprises recycled aggregate with nominal grain diameter of 0-2.36mm, 0.36-4.75 mm, 4.75-9.5 mm, 9.5-16 mm, 16-19 mm and 19-26.5 mm.

Preferably, the old asphalt pavement material is an old asphalt surface milling material, and the nominal particle size is less than or equal to 16 mm.

Preferably, in the waste cement concrete recycled aggregate and the old asphalt pavement material, the weight ratio of the aggregate with the nominal grain diameter of 0-2.36mm, 0.36-4.75 mm, 4.75-9.5 mm, 9.5-16 mm, 16-19 mm and 19-26.5mm is (18-25): 17-24): 14-19): 10-16): 4-10): 1-5.

By adopting the technical scheme, the content of the fine materials in the aggregate is a very important factor for determining the stability of the foamed asphalt. This is because foamed bitumen primarily coats the fine aggregate and forms a high viscosity bitumen mastic by which the coarse aggregate is combined to develop strength. Therefore, the proportion of the coarse aggregate and the fine aggregate in the aggregate is strictly controlled, so that the stability of the foamed asphalt mixture is improved, and the road performance is improved.

Preferably, the foaming agent is one or more of ethylene-vinyl acetate copolymer, styrene-butadiene latex, potassium cocoyl glycinate and organic silicon modified amine polyether.

By adopting the technical scheme, the ethylene-vinyl acetate copolymer, the styrene-butadiene latex, the cocoyl glycine potassium and the organic silicon modified amino polyether can effectively improve the foaming performance of the foamed asphalt, and the foaming agent is added into the foamed asphalt, so that the expansion rate of the foamed asphalt is up to 25%, the half-life period of the foamed asphalt can reach 50s, and the technical requirements of construction are fully met.

Preferably, the stabilizer is one or more selected from glass fiber, polyester fiber and wood fiber.

By adopting the technical scheme, the glass fiber, the polyester fiber and the wood fiber selected for use in the application have excellent flexibility and dispersibility, form a three-dimensional network structure after mixing, enhance the supporting force and the durability of a system, improve the stability, the strength, the compactness and the uniformity of the system, and improve the road performance of the foamed asphalt warm mix.

The second purpose of the application is as follows: the preparation method of the foamed asphalt warm-mix mixture comprises the following steps:

a. heating the matrix asphalt to 140-160 ℃, adding water containing a foaming agent and a stabilizing agent, wherein the mass of the water is 0.8-1.5% of that of the asphalt, and controlling the temperature of the water to be 30-50 ℃ to obtain foamed asphalt;

b. respectively heating the waste cement concrete recycled aggregate and the old asphalt pavement material to 95-130 ℃, preserving heat for 3-5h, mixing, and stirring at 95-130 ℃ for 40-90 s; adding the foamed asphalt prepared in the step a at the temperature of 130-; finally adding mineral powder preheated to 95-130 ℃, and mixing at 95-130 ℃ for 40-90s to obtain the asphalt mixture.

By adopting the technical scheme, the foaming process of the matrix asphalt is carried out in asphalt foaming equipment: firstly, high-pressure water flow is uniformly dispersed into a plurality of fine water body particles (similar to water mist) under the impact action of high-pressure steam, the fine water body particles are sprayed into high-temperature asphalt in a very short time, and the fine water body particles are vaporized almost simultaneously in a very short time due to great temperature difference. After they are coated by high-temp asphalt with a certain viscosity, they form a lot of honeycomb-like expanded air chambers. At the moment, the surface tension of the asphalt film outside the vaporized water body and the internal air pressure formed by the vaporized water body and the compressed air reach a transient relative equilibrium state. The three-phase mixture with the continuous expansion of the volume is sprayed out from the asphalt nozzle, and the foamed asphalt on the macroscopic state is formed. The water body particles dispersed in the hot asphalt are different in size and distribution, the volume of the formed honeycomb-shaped expanded air chamber and the thickness of the surface asphalt film are different, and the temperature of the asphalt film is suddenly reduced after the foamed asphalt is sprayed out, so that the viscosity of the asphalt film is increased, and the balance state is extremely unstable and is easy to break. Macroscopically, it appears that the foamed asphalt decays quickly after reaching the maximum expansion volume, restoring its original volume. As can be seen from the foaming mechanism of the asphalt, the foaming effect of the asphalt mainly depends on the temperature of the asphalt, the temperature of the foaming water and the amount of water for foaming.

This application has all been injectd this three parameter of pitch temperature, foaming temperature and foaming water consumption, and the expansion rate of improvement foaming pitch that can be fine prolongs half-life. This is because as the temperature of the asphalt increases and the amount of water used for foaming increases, the expansion rate of the foamed asphalt can be increased, but the half-life period decreases; along with the reduction of the temperature of the asphalt and the reduction of the water consumption for foaming, the expansion rate of the foamed asphalt is reduced, the half-life period is prolonged, and the two conditions are not beneficial to construction. Meanwhile, with the increase of the foaming water temperature, the expansion rate and the half-life period of the matrix asphalt are improved, but in order to achieve the purpose of saving energy, the foaming water temperature is limited to 30-50 ℃.

The mixing process of the foamed asphalt and the mixture is as follows: and when the aggregate is in a high-speed mixing state, simultaneously spraying foamed asphalt, wherein the asphalt can be subjected to short-term expansion and adhere to the aggregate, and then adding mineral aggregate to finally form the foamed asphalt mixture. The asphalt is mixed for three times in the process, the mixing temperature is limited to 95-140 ℃, and the technical requirement of warm mixing of the foamed asphalt is met. And even if the mixing temperature is reduced to 95 ℃, the foamed asphalt mixture can be uniformly mixed, completely wrapped, free of the phenomenon of white materials and good in mixing workability. When the mixing temperature is lower than 95 ℃, mineral aggregates which are not uniformly mixed exist at the edge part of the stirring pot, and the phenomenon of non-uniform coating tends to increase along with the reduction of the temperature. In addition, the mixing temperature is lower after the aggregate and the mineral aggregate are added, and the mixing temperature is increased after the foamed asphalt is added, so that the production cost is further reduced and the energy is saved on the premise of ensuring the uniformity of the prepared foamed asphalt mixture.

Compared with a hot-mix asphalt mixture, the warm-mix foamed asphalt mixture is reduced by 20-40 ℃, the aging degree of asphalt can be effectively reduced, the emission of harmful gases such as greenhouse gases and asphalt smoke is reduced, and the production and construction operation environment is greatly improved. But also can save the production energy consumption by more than 30 percent, and the production cost of each ton of mixture can be reduced by about 10 yuan.

Preferably, in the step a, the foaming temperature of the base asphalt is 150 ℃, the water consumption for foaming is 1 percent of the mass of the asphalt, and the water temperature is 40 ℃.

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

1. the application uses the construction industry garbage as the aggregate of the foamed asphalt warm-mix mixture, saves resources and protects the environment;

2. the foamed asphalt warm-mixing mixture has higher expansion rate and longer half-life period, the dispersion uniformity of the foamed asphalt in the formed mixture is high, and longer mixing time can be provided in the construction;

3. according to the method, the mixing temperature of the asphalt mixture is reduced by 20-40 ℃ by adopting a foam asphalt warm mixing technology, so that the discharge amount of harmful gas and dust can be greatly reduced, the construction operation environment is improved, the energy consumption in the production process is reduced, the construction season is prolonged, and the flexibility and the convenience of asphalt pavement construction are improved; the ageing of the asphalt cement in the production process can be reduced, and the pavement performance of the mixture can be improved.

Detailed Description

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

The utility model provides a bunton rock pitch is purchased from Beijing road good materials technique Limited company, model: RO-BRA;

the organosilicon modified amino polyether is purchased from Panjin Shengdaxin Petroleum technical service Co., Ltd, and has the model number: SDX-I;

the ethylene-vinyl acetate copolymer of the present application is purchased from Shanghai Yankee Biotech Co., Ltd, type: 55207339, respectively;

the styrene-butadiene latex is purchased from Jinluno chemical Co., Ltd, Jinan;

the potassium cocoyl glycinate of the application is purchased from Guangdong Gaohang science and technology Limited, model: GCK-12 k;

the polyester fibers of the present application are available from Tianyi engineering fibers, Inc., of Changzhou city;

the wood fibers of the present application are available from Changzhou Bo super engineering materials, Inc

The glass fibers of the present application are available from Shandong Daizian engineering materials, Inc.

Example 1

A preparation method of a foamed asphalt warm-mix mixture comprises the following steps:

a. heating 10kg of Buton rock asphalt to 140 ℃, adding 0.08kg of water containing 0.1kg of ethylene-vinyl acetate copolymer and 0.5kg of polyester fiber, and controlling the temperature of the water at 50 ℃ to obtain foamed asphalt;

b. respectively heating 100kg of waste cement concrete recycled aggregate and 800kg of waste asphalt pavement material to 95 ℃, preserving heat for 5 hours, then mixing, and stirring for 90s at 95 ℃; adding the foamed asphalt prepared in the step a at 140 ℃, and stirring for 40s at 140 ℃; and finally, adding 20kg of mineral powder preheated to 95 ℃, and stirring for 90s at 95 ℃ to obtain the asphalt mixture.

In the waste cement concrete recycled aggregate and the old asphalt pavement material, the weight ratio of the aggregate with the nominal grain diameter of 0-2.36mm, 0.36-4.75 mm, 4.75-9.5 mm, 9.5-16 mm, 16-19 mm and 19-26.5mm is 18:24:14:16:4: 5.

Example 2

A preparation method of a foamed asphalt warm-mix mixture comprises the following steps:

a. heating 60kg of Buton rock asphalt to 160 ℃, adding 0.9kg of water containing 0.5kg of styrene-butadiene latex and 0.1kg of glass fiber, and controlling the temperature of the water at 30 ℃ to obtain foamed asphalt;

b. respectively heating 400kg of waste cement concrete recycled aggregate and 200kg of waste asphalt pavement material to 130 ℃, preserving heat for 3h, then mixing, and stirring for 40s at 130 ℃; adding the foamed asphalt prepared in the step a at 130 ℃, and stirring for 90s at 130 ℃; finally, 200kg of mineral powder preheated to 130 ℃ is added, and the mixture is stirred for 40s at 130 ℃ to obtain the asphalt mixture.

In the waste cement concrete recycled aggregate and the old asphalt pavement material, the weight ratio of the aggregate with the nominal grain diameter of 0-2.36mm, 0.36-4.75 mm, 4.75-9.5 mm, 9.5-16 mm, 16-19 mm and 19-26.5mm is 25:17:19:10:10: 1.

Example 3

A preparation method of a foamed asphalt warm-mix mixture comprises the following steps:

a. heating 20kg of Buton rock asphalt to 145 ℃, adding 0.18kg of water containing 0.2kg of potassium cocoyl glycinate and 0.4kg of wood fibers, and controlling the temperature of the water at 35 ℃ to obtain foamed asphalt;

b. respectively heating 150kg of waste cement concrete recycled aggregate and 700kg of waste asphalt pavement material to 100 ℃, preserving heat for 3.5 hours, then mixing, and stirring for 80s at 100 ℃; adding the foamed asphalt prepared in the step a at 132 ℃, and stirring for 65s at 132 ℃; finally, 150kg of mineral powder preheated to 100 ℃ is added, and the mixture is stirred for 80s at 100 ℃ to obtain the asphalt mixture.

In the waste cement concrete recycled aggregate and the old asphalt pavement material, the weight ratio of the aggregate with the nominal grain diameter of 0-2.36mm, 0.36-4.75 mm, 4.75-9.5 mm, 9.5-16 mm, 16-19 mm and 19-26.5mm is 20:22:16:14:6: 4.

Example 4

A preparation method of a foamed asphalt warm-mix mixture comprises the following steps:

a. heating 50kg of Buton rock asphalt to 155 ℃, adding 0.6kg of water containing 0.4kg of organic silicon modified amino polyether and 0.2kg of polyester fiber, and controlling the temperature of the water at 45 ℃ to obtain foamed asphalt;

b. respectively heating 350kg of waste cement concrete recycled aggregate and 300kg of waste asphalt pavement material to 120 ℃, preserving heat for 4.5 hours, then mixing, and stirring for 50s at 120 ℃; b, adding the foamed asphalt prepared in the step a at 138 ℃, and stirring for 55s at 138 ℃; and finally, adding 50kg of mineral powder preheated to 120 ℃, and mixing for 50s at 120 ℃ to obtain the asphalt mixture.

In the waste cement concrete recycled aggregate and the old asphalt pavement material, the weight ratio of the aggregate with the nominal grain diameter of 0-2.36mm, 0.36-4.75 mm, 4.75-9.5 mm, 9.5-16 mm, 16-19 mm and 19-26.5mm is 24:19:18:12:8: 2.

Example 5

A preparation method of a foamed asphalt warm-mix mixture comprises the following steps:

a. heating 40kg of Buton rock asphalt to 150 ℃, adding 0.4kg of water containing 0.3kg of ethylene-vinyl acetate copolymer and 0.3kg of polyester fiber, and controlling the temperature of the water at 40 ℃ to obtain foamed asphalt;

b. respectively heating 250kg of waste cement concrete recycled aggregate and 500kg of waste asphalt pavement material to 110 ℃, preserving heat for 4 hours, then mixing, and stirring for 60s at 110 ℃; adding the foamed asphalt prepared in the step a at 135 ℃, and stirring for 60s at 135 ℃; finally, 100kg of mineral powder preheated to 110 ℃ is added, and the mixture is stirred for 60s at 110 ℃ to obtain the asphalt mixture.

In the waste cement concrete recycled aggregate and the old asphalt pavement material, the weight ratio of the aggregate with the nominal grain diameter of 0-2.36mm, 0.36-4.75 mm, 4.75-9.5 mm, 9.5-16 mm, 16-19 mm and 19-26.5mm is 22:21:17:13:7: 3.

Comparative example 1

The preparation method of the foamed asphalt warm-mix mixture is different from the embodiment 1 in that: no blowing agent was added.

Comparative example 2

The preparation method of the foamed asphalt warm-mix mixture is different from the preparation method of the embodiment 2 in that: no stabilizer was added.

Comparative example 3

The preparation method of the foamed asphalt warm-mix mixture is different from the embodiment 3 in that: the foaming temperature in step a was 130 ℃.

Comparative example 4

The preparation method of the foamed asphalt warm-mix mixture is different from the embodiment 3 in that: the foaming temperature in step a was 170 ℃.

Comparative example 5

The preparation method of the foamed asphalt warm-mix mixture is different from the embodiment 4 in that: the amount of foaming water is 3% of the mass of the asphalt.

Comparative example 6

The preparation method of the foamed asphalt warm-mix mixture is different from the embodiment 4 in that: the foaming water temperature was 10 ℃.

Comparative example 7

The preparation method of the foamed asphalt warm-mix mixture is different from the embodiment 5 in that: in the step b, after adding the foamed asphalt, the mixing temperature is 80 ℃.

Comparative example 8

The preparation method of the foamed asphalt warm-mix mixture is different from the embodiment 5 in that: in the step b, after adding the foamed asphalt, the mixing temperature is 160 ℃.

Performance testing

The dynamic stability of the foamed asphalt warm-mix mixture is tested according to road engineering asphalt and asphalt mixture test procedure T0719-2011;

the damage strain of the foamed asphalt warm-mix mixture is tested according to road engineering asphalt and asphalt mixture test procedure T0715-2011;

the soaking residual stability of the foamed asphalt warm-mix mixture is evaluated by adopting a soaking Marshall stability test method;

the freeze-thaw splitting residual strength ratio of the foamed asphalt warm-mix mixture is tested according to road engineering asphalt and asphalt mixture test procedure T0729-2000.

The results of the experiment are shown in Table 1.

The foamed asphalt warm-mix mixtures prepared in examples 1 to 5 had an expansion rate of more than 21%, half-lives of more than 50 seconds, high dispersion uniformity of foamed asphalt in the final-molded mixture, and slow attenuation of asphalt foam, and provided sufficient mixing time for construction. The foamed asphalt warm-mix mixtures prepared in examples 1 to 5 had good high-temperature stability, low-temperature stability and water stability. The dynamic stability is up to 2941 times/mm and is far higher than the standard requirement (more than or equal to 800 times/mm), which shows that the anti-rutting capability of the foam warm-mix asphalt mixture is strong; the damage strain reaches 2713.4ug which is far higher than the standard requirement (more than or equal to 2000ug), because the molding temperature of the foamed asphalt warm-mix mixture is lower, the aging degree of the asphalt is reduced, and the improvement of the low-temperature crack resistance of the mixture is very favorable; the stability of the soaking residual is as high as 92.6 percent and is far higher than the standard requirement (more than or equal to 80 percent), and the foam warm mix asphalt mixture has better water stability and stronger water damage resistance under the high-temperature condition; the freeze-thaw splitting residual strength ratio is as high as 86.9 and is far higher than the standard requirement (more than or equal to 75 percent), which indicates that the freeze-thaw water damage resistance of the foam warm mix asphalt mixture is stronger. In addition, the foamed asphalt warm-mix mixtures prepared in examples 1 to 5 were uniformly mixed, had no float phenomenon, were completely wrapped and adhered, were quickly and uniformly mixed, and were easily mixed.

Comparative example 1 differs from example 1 in that no blowing agent is added. As can be seen from the table 1, the expansion rate and the half-life period of the foamed asphalt are both greatly reduced, and the experimental result shows that the expansion rate and the half-life period of the foamed asphalt can be effectively increased by adding the foaming agent into the mixture, so that the stability of the prepared foamed asphalt warm-mix mixture is ensured, and the construction is more convenient.

Comparative example 2 differs from example 2 in that no stabilizer is added. As can be seen from Table 1, the high temperature stability, the low temperature stability and the water stability of the foamed asphalt warm mix are all greatly reduced. The experimental result shows that the stabilizer has obvious improvement on the anti-rutting capability, the low-temperature anti-cracking performance, and the high-temperature and low-temperature water damage resistance of the foam warm-mix asphalt mixture.

Comparative examples 3 and 4 differ from example 3 in the foaming temperature. As can be seen from Table 1, too high or too low a foaming temperature has a significant effect on both the expansion ratio and the half-life of the foamed bitumen. Experimental results show that the expansion rate of the foamed asphalt can be increased by increasing the foaming temperature, but the half-life period is reduced; while a decrease in foaming temperature may increase the half-life of the foamed asphalt, it may decrease the expansion rate.

Comparative example 5 differs from example 4 in that the amount of foaming water is increased. As can be seen from Table 1, increasing the amount of foaming water increases the expansion rate of the foamed bitumen, but decreases the half-life. Meanwhile, the foaming water amount is increased, and the water stability of the foamed asphalt warm-mix mixture is also reduced. This is because there are a large number of dispersed residual water molecules inside the foamed asphalt warm mix, increasing the possibility that the mix is damaged by water, thereby reducing the residual stability and the freeze-thaw split residual strength ratio. Experimental results show that the foaming water amount is an important control index in the foaming process of the foaming asphalt.

Comparative example 6 differs from example 4 in that the foaming water temperature is low. As can be seen from Table 1, the temperature of the foaming water is reduced, and the expansion rate and half-life of the foamed asphalt are reduced. The experimental result shows that the foaming water temperature has obvious influence on the expansion rate and the half-life period of the foamed asphalt.

Comparative examples 7 and 8 are different from example 5 in the mixing temperature after adding foamed asphalt, and it can be seen from table 1 that the aggregate and foamed asphalt are hardly mixed and are not uniformly mixed after the mixing temperature is lowered; after the mixing temperature is increased, although the aggregate and the foamed asphalt are easy to mix and are uniformly mixed, the mixing temperature is too high, a large amount of harmful gas and dust are generated, and the production cost of the foamed asphalt mixture is increased.

The embodiments of the present invention are preferred embodiments of the present application, and the scope of protection of the present application is not limited by the embodiments, so: all equivalent changes made according to the structure, shape and principle of the present application shall be covered by the protection scope of the present application.

Claims (9)

1. The foamed asphalt warm-mix mixture is characterized by comprising the following components in parts by weight:

1-6 parts of foamed asphalt;

10-40 parts of waste cement concrete recycled aggregate;

20-80 parts of old asphalt pavement material;

2-20 parts of mineral powder;

0.01-0.05 part of foaming agent;

0.01-0.05 part of stabilizer.

2. The foamed asphalt warm mix according to claim 1, characterized by comprising the following components in parts by weight:

2-5 parts of foamed asphalt;

15-35 parts of waste cement concrete recycled aggregate;

30-70 parts of old asphalt pavement material;

5-15 parts of mineral powder;

0.02-0.04 part of foaming agent;

0.02-0.04 part of stabilizer.

3. The foamed asphalt warm mix according to claim 1 or 2, wherein the waste cement concrete recycled aggregate comprises recycled aggregate having a nominal particle size of 0-2.36mm, 0.36-4.75 mm, 4.75-9.5 mm, 9.5-16 mm, 16-19 mm, 19-26.5 mm.

4. The foamed asphalt warm mix material according to claim 3, wherein the old asphalt pavement material is an old asphalt pavement milling material, and the nominal particle size is less than or equal to 16 mm.

5. The foamed asphalt warm-mix material according to claim 4, wherein the weight ratio of aggregates having nominal particle diameters of 0-2.36mm, 0.36-4.75 mm, 4.75-9.5 mm, 9.5-16 mm, 16-19 mm, 19-26.5mm in the waste cement concrete recycled aggregates and the old asphalt pavement materials is (18-25): 17-24): 14-19): 10-16): 4-10: 1-5.

6. The foamed asphalt warm mix mixture according to claim 1 or 2, wherein the foaming agent is one or more selected from ethylene-vinyl acetate copolymer, styrene-butadiene latex, potassium cocoyl glycinate and silicone modified amine-based polyether.

7. The warm mix of foamed asphalt according to claim 1 or 2, wherein the stabilizer is one or more selected from the group consisting of glass fiber, polyester fiber and wood fiber.

8. A method for preparing a foamed asphalt warm mix according to any one of claims 1 to 7, characterized in that: the method comprises the following steps:

a. heating the matrix asphalt to 140-160 ℃, adding water containing a foaming agent and a stabilizing agent, wherein the mass of the water is 0.8-1.5% of that of the asphalt, and controlling the temperature of the water to be 30-50 ℃ to obtain foamed asphalt;

b. respectively heating the waste cement concrete recycled aggregate and the old asphalt pavement material to 95-130 ℃, preserving heat for 3-5h, mixing, and stirring at 95-130 ℃ for 40-90 s; adding the foamed asphalt prepared in the step a at the temperature of 130-; finally adding mineral powder preheated to 95-130 ℃, and mixing at 95-130 ℃ for 40-90s to obtain the asphalt mixture.

9. The method for preparing the foamed asphalt warm-mix material according to claim 8, characterized in that: in the step a, the foaming temperature of the matrix asphalt is 150 ℃, the water consumption for foaming is 1 percent of the mass of the asphalt, and the water temperature is 40 ℃.