CN111747715A

CN111747715A - Semi-permeable emulsified asphalt mixture and preparation method thereof

Info

Publication number: CN111747715A
Application number: CN202010645909.8A
Authority: CN
Inventors: 欧阳春发; 李伟; 高群; 王强; 吴修春
Original assignee: Shanghai Institute of Technology
Current assignee: Huzhou Hedatuhong New Material Technology Co ltd
Priority date: 2020-07-07
Filing date: 2020-07-07
Publication date: 2020-10-09
Anticipated expiration: 2040-07-07
Also published as: CN111747715B

Abstract

The invention discloses a semi-permeable emulsified asphalt mixture and a preparation method thereof. The asphalt mixture comprises emulsified asphalt, aggregates, a calcium oxide curing agent, a wave absorbing agent and fibers. The preparation method comprises the following steps: pouring the aggregate and the calcium oxide into a stirrer for mixing; adding water into a stirrer, and mixing; mixing the emulsified asphalt and the curing agent, adding the mixture into a stirrer, adding the wave absorbing agent and the fibers simultaneously, and uniformly mixing. The invention utilizes the microwave heating principle, can simultaneously separate out the internal water and the external water, and simultaneously utilizes the fiber capillary phenomenon, and the mixture is added at the later stage of mixing, like giving oxygen channels to the caking of the soil stack plates, so that the water is volatilized in the micro-channels. Therefore, the early-stage moisture is quickly volatilized, and the early-stage strength of the road surface is improved, so that the early-stage opening of traffic is realized. Meanwhile, the water treatment agent does not contain an additional low-molecular ionic emulsifier, so that the water pollution is reduced, the energy loss is greatly reduced, and the environmental pollution is improved.

Description

Semi-permeable emulsified asphalt mixture and preparation method thereof

Technical Field

The invention relates to an asphalt mixture and a preparation method thereof, in particular to an asphalt mixture which has strong anti-rutting capability, high early pavement strength due to easy volatilization of early moisture and environmental protection and water permeability functions and a preparation method thereof, and belongs to the technical field of asphalt materials.

Background

Along with the development of the traffic industry, the conditions of heavy load and overload are increased rapidly, and the problems of pavement cracks and ruts are endless, so that higher requirements on the shearing resistance of the asphalt pavement are provided. In order to delay the generation of diseases such as asphalt pavement cracks, ruts and the like and prolong the service life of the asphalt pavement. The epoxy resin can obviously improve the strength of the asphalt, thereby improving the anti-rutting capability of the mixture.

At present, in the aspect of producing asphalt mixtures, hot-mixed asphalt mixtures are mainly used all over the world, asphalt and aggregates are heated to a high enough temperature by the technology and then are mixed at the temperature generally higher than 150 ℃, so that a large amount of energy is wasted, harmful gases are released by the asphalt due to heating, the generated waste gases seriously pollute the environment, and the human health is seriously influenced.

The preparation of the semi-permeable emulsified asphalt mixture belongs to a cold-mixing and cold-paving construction technology, so that on the premise of not influencing the performances of various aspects of asphalt, the mixing temperature can be reduced, the energy is saved, the emission of waste gas generated in the production process can be reduced, and the problem of environmental pollution is greatly improved.

The presence of water in the emulsified asphalt is twosided. On one hand, the emulsified asphalt is not easy to solidify at normal temperature due to the existence of water, and has the characteristics of long storage time, environmental protection and the like; on the other hand, after the pavement is paved, the volatilization of water depends heavily on the temperature and humidity, and the weather does not shift with the will of people, which also becomes a big problem of traffic after construction. As is known, the emulsified asphalt contains 40% or more of water, and after the emulsified asphalt is mixed with aggregate, the water on the surface of the mixture is volatilized firstly and is cemented into a film, so that the internal water of the mixture is difficult to volatilize, the early strength of the mixture is insufficient, and the early traffic is difficult to realize.

The existing emulsified asphalt mixture generally adopts physical and chemical methods to solve the problem of water, which often produces contradictions; molecular sieves, halloysite and the like can absorb trace moisture, but are difficult to volatilize in the cementing process and have slightly high cost; the key is the proportion of CaO, cement and the like to water; the hot air drying is suitable for ultrathin pavements, but for airport roads of more than 3 cm, the ultrathin pavements can only be dried through the surface, but the inherent water is difficult to volatilize because the surface of the water is cemented into a layer of film.

Disclosure of Invention

The technical problem to be solved by the invention is as follows: the early moisture of the emulsified asphalt is not easy to volatilize, so that the early strength is not enough.

In order to solve the technical problems, the invention adopts the technical scheme that:

the semi-permeable emulsified asphalt mixture is characterized by comprising emulsified asphalt, aggregates, a calcium oxide curing agent, a wave absorbing agent and fibers.

Preferably, the emulsified asphalt accounts for 6-8% of the aggregate mass; the calcium oxide accounts for 2-3% of the mass of the aggregate; the curing agent accounts for 3-5% of the mass of the emulsified asphalt; the wave absorbing agent accounts for 1-2% of the mass of the aggregate; the fiber accounts for 0.2-0.3% of the aggregate mass.

Preferably, the emulsified asphalt adopts the epoxy resin/vinyl copolymer modified water-based emulsified asphalt with the mass addition of the water-based epoxy resin being 5%.

More preferably, the emulsified asphalt is at least one of natural asphalt, petroleum asphalt, coal tar asphalt and oil sand asphalt.

The aggregate can be selected according to the needs and is not limited to crushed stones. The aggregate is divided into coarse aggregate and fine aggregate, the grain size of the fine aggregate is not more than 5mm, the grain size of the coarse aggregate is 10-20 mm, the aggregate with a single grain size range can be adopted, and the compound material of the coarse aggregate and the fine aggregate can also be adopted as the aggregate.

When the aggregate adopts compound ingredients, the grading selection of the aggregate is as follows: 15-20% of particles with the particle size of less than 3mm, 50-55% of particles with the particle size of 5-10 mm and 30-35% of particles with the particle size of 10-15 mm.

Preferably, limestone is used as the aggregate with the grain size of less than 3mm, basalt is used as the aggregate with other grain sizes, and normal-temperature stacking dry aggregate is selected to prevent the influence on the addition amount of water.

Preferably, the calcium oxide is industrial-grade calcium oxide.

Preferably, the curing agent is a fatty polyamine type curing agent.

More preferably, the curing agent is at least one of ethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, dipropylenetriamine, dimethylpropylamine and diethylaminopropylamine.

Preferably, the wave absorbing agent is carbonyl iron powder.

Preferably, the fiber is at least one of polyester fiber, carbon fiber and polypropylene fiber for road, and the length of the fiber is 6 +/-1 mm.

The invention also provides a preparation method of the semi-permeable emulsified asphalt mixture, which is characterized by comprising the following steps:

step 1): pouring the aggregate and the calcium oxide into a stirrer for mixing; the calcium oxide mainly plays a role in absorbing redundant water in the mixture, and simultaneously, the calcium oxide reacts with water to generate a heat release phenomenon, so that the loss of water in the emulsified asphalt mixture is accelerated.

Step 2): adding water with the aggregate mass of 1-2% into a stirrer, and mixing; the water is mainly used for wetting stone materials, so that the emulsified asphalt and the stone materials are conveniently and fully bonded.

Step 3): mixing the emulsified asphalt and the curing agent, adding the mixture into a stirrer, adding the wave absorbing agent and the fibers simultaneously, and uniformly mixing.

Preferably, the mixing time in step 1) is 60 to 120s, preferably 90 s; and (4) stirring the mixture in the step 4) by using a stirrer, and then stir-frying the mixture by using a shovel to prevent the mixture from being not uniform enough.

The emulsified asphalt mixture has high shearing resistance and obvious high temperature performance, and can reduce the generation of cracks and ruts on asphalt pavements. The porosity of the emulsified asphalt mixture reaches 20%, the communication porosity can reach 8.5-16%, and the emulsified asphalt mixture plays a role in a permeable pavement. The emulsified asphalt mixture of the invention not only can effectively ensure the strength and stability of the pavement, but also has high construction speed.

According to the invention, the wave absorbing agent is added into the emulsified asphalt mixture and is irradiated by electromagnetic waves, so that the internal water and the external water of the mixture can be effectively removed; the added fibers can effectively separate out the water in the mixture through the fiber capillary phenomenon, and the fibers are added into the mixture to play a reinforcement role, so that the progress modulus of the mixture is increased, and the fatigue resistance of the mixture is improved.

The invention utilizes the microwave heating principle, can simultaneously separate out the internal water and the external water, and simultaneously utilizes the fiber capillary phenomenon, and the mixture is added at the later stage of mixing, like giving oxygen channels to the caking of the soil stack plates, so that the water is volatilized in the micro-channels. Therefore, the early-stage moisture is quickly volatilized, and the early-stage strength of the road surface is improved, so that the early-stage opening of traffic is realized. Meanwhile, the water treatment agent does not contain an additional low-molecular ionic emulsifier, so that the water pollution is reduced, the energy loss is greatly reduced, and the environmental pollution is improved.

Detailed Description

In order to make the invention more comprehensible, preferred embodiments are described in detail below.

In the examples, the percentages of various substances are by mass unless otherwise specified.

The determination of the void ratio is calculated according to the formula described in road engineering asphalt mixture test protocol JTG E20-2011 (T0705-4).

The interconnected porosity of the test piece was measured using the following formula:

the dynamic stability is measured according to the test standard of road engineering asphalt mixture test specification JTG E20-2011 (T0719-2011).

The determination of the freeze-thaw splitting strength ratio is carried out according to the test standard of road engineering asphalt mixture test regulation JTG E20-2011 (T0729-2000).

The compression strength is tested by a microcomputer controlled electronic universal tester with the model of CMT5305 and the loading speed of 50mm/min +/-5 mm/min.

Example 1

The preparation method of the semi-permeable emulsified asphalt mixture comprises the following steps:

weighing stones (suppliers, Shanghai road and bridge groups) with corresponding mass according to the proportion, wherein the grading selection of aggregate is as follows: 16% of the mixture with the grain diameter of 0-3 mm, 52% of the mixture with the grain diameter of 5-10 mm and 32% of the mixture with the grain diameter of 10-15 mm is poured into an asphalt mixture stirrer together with calcium oxide (supplier, Tatan technology) with the mass of 2.5% of the mass of the aggregate, and the machine is started to mix the aggregate and the calcium oxide for 90 s;

secondly, 60g of water is added, the machine is started, and the mixture is uniformly mixed;

weighing 480g of emulsified asphalt (supplier, Shanghai Yinzhi Co., Ltd., product name: epoxy resin/vinyl copolymer modified water-based emulsified asphalt) and 16.8g of curing agent (supplier, Shanghai Heda), stirring uniformly, and adding into the aggregate;

starting the asphalt mixture stirrer, stirring for 90s, and after the mixing is finished, stirring and frying by using a small shovel to prevent the mixture from being not uniform enough, and obtaining the required mixture after the mixture is uniform.

Unless otherwise specified, the stone, calcium oxide, emulsified asphalt and curing agent referred to in the following examples are all the same supplier.

Example 2

weighing stone materials with corresponding mass according to the proportion, wherein the grading selection of the aggregate is as follows: 16% of calcium oxide with the mass of 2.5% of the aggregate, 52% of calcium oxide with the particle size of 0-3 mm, 32% of calcium oxide with the particle size of 5-10 mm and the particle size of 10-15 mm, and pouring the calcium oxide and the calcium oxide into an asphalt mixture stirring machine, starting the machine, and stirring the aggregate and the calcium oxide for 90 s;

③ weighing 480g of emulsified asphalt and 16.8g of curing agent, stirring uniformly, adding into the aggregate, and simultaneously adding 50g of carbonyl iron powder;

Example 3

③ 480g of emulsified asphalt and 16.8g of curing agent are weighed, stirred evenly and added into aggregate, and 10g of polyester fiber (Changsha lemon aus building materials Co., Ltd.) is added at the same time;

Example 4

③ 480g of emulsified asphalt and 16.8g of curing agent are weighed and added into the aggregate after being evenly stirred; 50g of carbonyl iron powder and 10g of polyester fiber were added simultaneously.

Example 5

③ 480g of emulsified asphalt and 16.8g of curing agent are weighed and added into the aggregate after being evenly stirred; 10g of carbon fiber (supplier, Shanghai Shuo, cat No. 058) was added at the same time.

Example 6

③ 480g of emulsified asphalt and 16.8g of curing agent are weighed and added into the aggregate after being evenly stirred; at the same time, 10g of polypropylene fibers (Changshagan auspicious building materials Co., Ltd.) were added.

The emulsified asphalt mixtures obtained in examples 1 to 6 were subjected to the relevant performance tests, and the results are shown in Table 1.

TABLE 1

Sample (I)	Porosity%	The interconnected porosity%	Dynamic stability degree of times/mm	The freeze-thaw splitting strength is more than%
					Example 1	18.6	10.5	36528	76.8
Example 2	18.3	10.1	34528	76.5
					Example 3	18.0	9.60	37526	75.8
Example 4	18.1	9.40	37354	75.2
					Example 5	17.8	9.50	37426	75.4
Example 6	18.0	9.65	37456	75.6

The early strength of the mixture is usually verified after the test piece is spread for 5h, and the magnitude of the early strength is often influenced by the amount of moisture in the mixture. The samples 1, 3, 5 and 6 were cured at room temperature outdoors, and the samples 2 and 4 were cured outdoors after being irradiated with microwaves for 1.5 min. Early water loss was compared and the results are shown in table 2.

TABLE 2

Sample (I)	5h water loss/g
		Example 1	5.9
Example 2	11.1
		Example 3	8.4
Example 4	12.6
		Example 5	10.3
Example 6	9.4

The Marshall test piece which is kept for 5 hours outdoors is tested for the compression strength through a microcomputer controlled electronic universal tester, and the compression strength is quickly tested to be used as the early strength of the test piece. The loading rate was 50 mm/min. The compressive strengths are shown in Table 3.

TABLE 3

Sample (I)	Compressive strength/kN
		Example 1	12.0
Example 2	24.0
		Example 3	15.6
Example 4	25.6
		Example 5	16.5
Example 6	20.2

As can be seen from the data in Table 1, the pavement performance of the asphalt mixture obtained by the invention is higher than the requirements specified in the Water-based epoxy resin emulsified asphalt mixture for roads. Compared with the common asphalt mixture, the semi-permeable emulsified asphalt mixture prepared by the embodiments of the invention has obviously improved high-temperature rutting resistance, low-temperature cracking resistance, water permeability and early strength, which shows that the semi-permeable emulsified asphalt mixture prepared by the invention has excellent pavement performance. As can be seen from the data in Table 2, the addition of carbonyl iron powder and the fiber can effectively remove the inherent moisture of the mixture, and the addition of carbonyl iron powder and the fiber has more remarkable effect, so that the early strength of the mixture can be effectively improved (the compressive strength can reach 25.6kN as shown in Table 3), and the polypropylene fiber has better effect.

Claims

1. The semi-permeable emulsified asphalt mixture is characterized by comprising emulsified asphalt, aggregates, a calcium oxide curing agent, a wave absorbing agent and fibers.

2. The semi-permeable emulsified asphalt mixture according to claim 1, wherein the emulsified asphalt is 6-8% of the aggregate mass; the calcium oxide accounts for 2-3% of the mass of the aggregate; the curing agent accounts for 3-5% of the mass of the emulsified asphalt; the wave absorbing agent accounts for 1-2% of the mass of the aggregate; the fiber accounts for 0.2-0.3% of the aggregate mass.

3. The semi-permeable emulsified asphalt mixture according to claim 1, wherein the emulsified asphalt is an epoxy resin/vinyl copolymer modified water-based emulsified asphalt with the mass addition of 5% of the aqueous epoxy resin.

4. The semi-permeable emulsified asphalt mixture as set forth in claim 1, wherein said aggregate is selected from the group consisting of: 15-20% of particles with the particle size of less than 3mm, 50-55% of particles with the particle size of 5-10 mm and 30-35% of particles with the particle size of 10-15 mm.

5. The semi-permeable emulsified asphalt mixture according to claim 1 or 4, wherein limestone is used as the aggregate having a particle size of less than 3mm, and basalt is used as the other particle size.

6. The semi-permeable emulsified asphalt mixture as set forth in claim 1, wherein said calcium oxide is technical grade calcium oxide.

7. The semi-permeable emulsified asphalt mixture as set forth in claim 1, wherein said curing agent is a fatty polyamine type curing agent.

8. The semi-permeable emulsified asphalt mixture according to claim 7, wherein the curing agent is at least one of ethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, dipropylenetriamine, dimethylpropylamine and diethylaminopropylamine.

9. The semi-permeable emulsified asphalt mixture as set forth in claim 1, wherein said wave-absorbing agent is carbonyl iron powder.

10. The semi-permeable emulsified asphalt mixture as set forth in claim 1, wherein said fibers are at least one of polyester fibers, carbon fibers and polypropylene fibers, and have a length of 6 ± 1 mm.

11. The method for preparing a semi-permeable emulsified asphalt mixture according to any one of claims 1 to 10, comprising the steps of:

step 1): pouring the aggregate and the calcium oxide into a stirrer for mixing;

step 2): adding water with the aggregate mass of 1-2% into a stirrer, and mixing;

12. The method for preparing a semi-permeable emulsified asphalt mixture according to claim 11, wherein the mixing time in the step 1) is 60-120 s; and (4) stirring the mixture in the step 4) by using a stirrer, and then stir-frying by using a shovel.