CN114671652B - Room-temperature mixing dough mixing material and preparation method thereof - Google Patents

Abstract

The room-temperature mixing pavement mixture comprises mineral aggregate, emulsified asphalt, aqueous polyurethane emulsion, cement, a defoaming agent and a retarder, wherein the emulsified asphalt, the aqueous polyurethane emulsion, the cement, the defoaming agent and the retarder form a cementing material, and the mineral aggregate comprises coarse aggregate, fine aggregate and filler; 8 to 15 parts of cementing material and 100 parts of mineral material by weight; 100 parts of emulsified asphalt, 60-80 parts of aqueous polyurethane emulsion, 1-18 parts of cement, 1-3 parts of defoamer and 0-0.3 part of retarder in the cementing material. The waterborne polyurethane disclosed by the invention can improve the mechanical property and enhance the bonding property of the emulsified asphalt; the addition of a small amount of cement can promote the formation of the strength of the mixture, reduce the cost of raw materials and greatly improve the strength of the mixture. The mixture obtained by the invention has excellent performance, high strength and simple and convenient preparation, can realize mixing construction at room temperature, and is energy-saving and environment-friendly.

Description

Room-temperature mixing dough mixing material and preparation method thereof

Technical Field

The invention relates to the field of new pavement materials, in particular to a room-temperature mixing pavement mixture and a preparation method thereof.

Background

Asphalt and modified asphalt are common cementing materials for pavement materials. The production process needs to heat the mineral aggregate to more than 190 ℃, and the asphalt is also heated to about 180 ℃ to complete the mixing, transportation, paving and rolling of the asphalt pavement mixture, and finally the asphalt pavement is formed. The hot-mixing hot-paving mode consumes a large amount of energy, and can release a large amount of harmful smoke to influence the environment and the health of constructors. Meanwhile, in the use process of the asphalt pavement, diseases such as ruts, cracks, water damage and the like are easy to occur. Therefore, the research on the room temperature mixed pavement mixture with excellent performance and the preparation method thereof are urgently needed.

Polyurethane is a potential road material, and can be physically and chemically reacted with the components of emulsified asphalt at room temperature, so as to promote demulsification of the emulsified asphalt and obviously improve the road performance of the emulsified asphalt. The cementing material prepared by emulsified asphalt is added into polyurethane, so that the room-temperature mixing construction can be realized, the good performance of the polyurethane is kept, and the application range of the polyurethane in road materials is greatly expanded.

However, the polyurethane-emulsified asphalt mixture still has certain defects: the price of polyurethane is high, and the cost of the polyurethane-emulsified asphalt mixture is obviously higher than that of the common modified asphalt mixture; the strength of the room-temperature polyurethane-emulsified asphalt mixture is slow to form, and the polyurethane-emulsified asphalt mixture is not beneficial to opening traffic as soon as possible.

The cement is a powdery hydraulic inorganic gel material, and the main components include calcium oxide, silicon dioxide, iron oxide, aluminum oxide, etc., and can be hardened in air or water. The cement has low cost, easily obtained materials, quick early strength increase and high strength after hardening, and is an important building material. A small amount of cement is added into a polyurethane-emulsified asphalt system, so that the strength of the mixture can be effectively improved.

Therefore, polyurethane, emulsified asphalt and cement are needed to be used as main raw materials of cementing materials, and an asphalt pavement mixture which is prepared and used at room temperature, has lower cost, is durable and is environment-friendly is developed.

Disclosure of Invention

The technical problem to be solved is as follows: the invention provides a room-temperature mixing road surface mixture and a preparation method thereof, aiming at solving the problems of insufficient high-temperature construction and performance of the existing asphalt mixture, improving the strength and water stability of the mixture, and adapting to heavy traffic volume and energy-saving and environment-friendly requirements.

The technical scheme is as follows: the room-temperature mixing pavement mixture comprises mineral aggregate, emulsified asphalt, aqueous polyurethane emulsion, cement, a defoaming agent and a retarder, wherein the emulsified asphalt, the aqueous polyurethane emulsion, the cement, the defoaming agent and the retarder form a cementing material, and the mineral aggregate comprises coarse aggregate, fine aggregate and filler; 8 to 15 parts of cementing material and 100 parts of mineral material by weight; 100 parts of emulsified asphalt, 60 to 80 parts of waterborne polyurethane emulsion, 1 to 18 parts of cement, 1 to 3 parts of defoamer and 0 to 0.3 part of retarder.

Preferably, the coarse aggregate is basalt or diabase, and the fine aggregate and the filler are limestone.

Preferably, the nominal particle size delta of the coarse aggregate is larger than 4.75mm, the nominal particle size delta of the fine aggregate is larger than 0.075mm and smaller than delta and smaller than 4.75mm, and the nominal particle size delta of the filler is smaller than or equal to 0.075mm.

Preferably, the emulsified asphalt is at least one of cationic emulsified asphalt, anionic emulsified asphalt and nonionic emulsified asphalt.

Preferably, the solid content of the emulsified asphalt is more than or equal to 50 percent.

Preferably, the aqueous polyurethane emulsion is an emulsion or dispersion of aqueous polyurethane, and the solid content of the aqueous polyurethane emulsion is 30-50%.

Preferably, the cement is at least one of ordinary portland cement having a strength grade of 52.5, 52.5R and road portland cement having a strength grade of 52.5.

Preferably, the defoaming agent is at least one of mineral oil, dimethyl silicone oil, stearic acid and monolauryl butyl stearate.

Preferably, the retarder is at least one of acetic acid, tartaric acid and an oxyphosphate compound with a surface activity effect.

The preparation method of the road surface mixture mixed at room temperature comprises the following steps:

step 1) fully drying the screened mineral aggregate and the cement powder for later use;

step 2) placing the coarse aggregate and the fine aggregate with the grain size larger than 0.6mm into a stirring pot, adding the waterborne polyurethane emulsion, the defoaming agent and the retarder, and stirring for 40-60s at room temperature;

step 3), adding fine aggregates with the particle size of less than or equal to 0.6mm and fillers, and continuously stirring for 60-90s;

and 4) adding emulsified asphalt and cement, and continuously stirring for 60-90s to obtain the pavement mixture.

The invention utilizes the reaction of polyurethane and emulsified asphalt at room temperature, and the crosslinking reaction involved in the polyurethane-emulsified asphalt cementing material is as follows:

1) The aqueous polyurethane reacts with water in the emulsified asphalt to generate urea bonds and carbon dioxide:

2) Further generation of a cross-linked structure:

the polyurethane and the emulsified asphalt are subjected to physical change and chemical change simultaneously, and linear cross-linked gel generated by the reaction of the polyurethane forms a three-dimensional network structure in the emulsified asphalt, so that the mechanical property of the mixture is improved.

The chemical formula of the hydration reaction of the ordinary portland cement is as follows:

(1) In the early stage of cement hydration, tricalcium silicate reacts with water to form hydrated calcium silicate gel and calcium hydroxide:

(2) In the later stage of cement hydration, the dicalcium silicate reacts with water to generate hydrated calcium silicate gel and calcium hydroxide:

the cement hydration product mainly comprises hydrated calcium silicate gel (C-S-H gel) and calcium hydroxide, wherein the hydrated calcium silicate accounts for 70-80% of the hydration product and forms a main strength source after the cement is hydrated. The cement is added into the polyurethane-emulsified asphalt system, and the hydrated calcium silicate gel further strengthens the three-dimensional network structure of the system.

Has the advantages that:

(1) The invention adopts emulsified asphalt, waterborne polyurethane and cement as main raw materials of cementing materials, and forms a three-dimensional composite network structure through the curing action of the polyurethane and the hydration action of the cement, thereby having good integrity and strong cohesiveness.

(2) Compared with the traditional high-viscosity modified asphalt mixture, the room-temperature mixed pavement mixture prepared by the invention has the advantages that the strength and the water stability are obviously improved, and the room-temperature mixed pavement mixture can be applied to heavy-load traffic pavements.

(3) The room-temperature mixed pavement mixture prepared by the invention realizes normal-temperature preparation and use, saves energy and reduces pollution compared with a hot-mixed hot-laid asphalt mixture, and is a novel pavement environment-friendly material.

Drawings

FIG. 1 is a schematic view of a preparation process.

Detailed Description

The invention is further described below with reference to specific examples. These examples are merely illustrative and do not limit the scope of the present invention in any way. It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention, and that such changes and modifications may be made without departing from the spirit and scope of the invention.

In the embodiment of the specification, the coarse aggregate is basalt or diabase, and the fine aggregate and the filler are limestone. The nominal grain diameter delta of the coarse aggregate is more than 4.75mm, the nominal grain diameter delta of the fine aggregate is more than 0.075mm and less than or equal to 4.75mm, and the nominal grain diameter delta of the filler is less than or equal to 0.075mm.

The emulsified asphalt is common commercial emulsified asphalt, and the solid content of the emulsified asphalt is more than or equal to 50 percent.

The aqueous polyurethane emulsion is an emulsion or dispersion of aqueous polyurethane, has a solid content of 30-50%, and can be prepared by common commercial products.

The cement is at least one of ordinary portland cement with a strength grade of 52.5 and 52.5R and road portland cement with a strength grade of 52.5.

The defoaming agent is at least one of mineral oil, dimethyl silicone oil, stearic acid and monolauryl butyl stearate.

The retarder is at least one of acetic acid, tartaric acid and an oxygen-containing phosphate compound with a surface activity effect.

Example 1

The mixture is prepared according to the following mass ratio:

cationic emulsified asphalt 100g

67g of aqueous polyurethane emulsion

P.O52.5 Cement 16.7g

Dimethyl Silicone oil (defoamer) 3g

0.2g of anhydrous tartaric acid (retarder)

Mineral aggregate 2000g

Referring to fig. 1, the preparation method of the room-temperature mixed pavement mixture comprises the following steps:

step 1) fully drying the screened mineral aggregate and the cement powder for later use;

step 2) placing coarse aggregates and fine aggregates with the particle size larger than 0.6mm into a stirring pot, adding the aqueous polyurethane emulsion, the defoaming agent and the retarder, and stirring for 40-60s at room temperature;

step 3) adding fine aggregates with the particle size of less than or equal to 0.6mm and fillers, and continuously stirring for 60-90s;

and 4) adding emulsified asphalt and cement, and continuously stirring for 60-90s to obtain the pavement mixture.

The raw materials are sequentially placed in a mixing pot according to the preparation flow and fully stirred, after stirring is completed, a mixture is taken out to prepare a test piece (the aggregate grading type is PAC-10), and the test piece is fully cured at room temperature.

Example 2

The mixture is prepared according to the following mass ratio:

cationic emulsified asphalt 100g

67g of aqueous polyurethane emulsion

P.O52.5 Cement 8.4g

Dimethicone oil (defoamer) 3g

0.2g of anhydrous tartaric acid (retarder)

1800g of mineral aggregate

Referring to fig. 1, the preparation method of the room-temperature mixed pavement mixture comprises the following steps:

step 1) fully drying the sieved mineral aggregate and cement powder for later use;

step 2) placing coarse aggregates and fine aggregates with the particle size larger than 0.6mm into a stirring pot, adding the aqueous polyurethane emulsion, the defoaming agent and the retarder, and stirring for 40-60s at room temperature;

step 3), adding fine aggregates with the particle size of less than or equal to 0.6mm and fillers, and continuously stirring for 60-90s;

and 4) adding emulsified asphalt and cement, and continuously stirring for 60-90s to obtain the pavement mixture.

The raw materials are sequentially placed in a stirring pot to be fully stirred according to the preparation flow, after the stirring is finished, the mixture is taken out to prepare a test piece (the aggregate grading type is PAC-10), and the test piece is fully maintained at room temperature.

Example 3

The mixture is prepared according to the following mass ratio:

cationic emulsified asphalt 100g

67g of aqueous polyurethane emulsion

P.O52.5 Cement 1.6g

Dimethicone oil (defoamer) 3g

0.2g of anhydrous tartaric acid (retarder)

1600g of mineral aggregate

Referring to fig. 1, the preparation method of the room-temperature mixed pavement mixture comprises the following steps:

step 1) fully drying the sieved mineral aggregate and cement powder for later use;

step 2) placing the coarse aggregate and the fine aggregate with the grain size larger than 0.6mm into a stirring pot, adding the waterborne polyurethane emulsion, the defoaming agent and the retarder, and stirring for 40-60s at room temperature;

step 3) adding fine aggregates with the particle size of less than or equal to 0.6mm and fillers, and continuously stirring for 60-90s;

and 4) adding emulsified asphalt and cement, and continuously stirring for 60-90s to obtain the pavement mixture.

The raw materials are sequentially placed in a stirring pot to be fully stirred according to the preparation flow, after the stirring is finished, the mixture is taken out to prepare a test piece (the aggregate grading type is PAC-10), and the test piece is fully maintained at room temperature.

Example 4

The method is the same as the embodiment 1 except that the mixture is prepared according to the following mass ratio:

cationic emulsified asphalt 100g

60g of waterborne polyurethane emulsion

P.O52.5 Cement 1g

Dimethicone oil (defoamer) 1g

Mineral aggregate 1296g

Example 5

The difference from the embodiment 1 is that the mixture is prepared according to the following mass ratio:

cationic emulsified asphalt 100g

Aqueous polyurethane emulsion 80g

18g of P.O52.5 cement

Dimethyl Silicone oil (defoamer) 3g

0.3g of anhydrous tartaric acid (retarder)

3060g mineral aggregate

Comparative example 1

The mixture is prepared according to the following mass ratio:

70 ^# base asphalt 100g

12g of high-viscosity modifier

Mineral aggregate 2000g

The mixture aggregate grading adopts PAC-10.

The high-viscosity modifier is a high-viscosity modified additive product of national high-tech (Beijing) engineering research institute Limited.

Heating the matrix asphalt to 160 ℃, adding a high-viscosity modifier, adding mineral aggregate with the temperature of 190 ℃, mixing at 160 ℃ to prepare a test piece, and obtaining the high-viscosity modified asphalt PAC-10 mixture test piece.

Comparative example 2

The mixture is prepared according to the following mass ratio:

cationic emulsified asphalt 100g

Aqueous polyurethane 67g

Dimethicone oil (defoamer) 3g

0.2g of anhydrous tartaric acid (retarder)

1600g of mineral aggregate

The raw materials are sequentially placed in a mixing pot according to the preparation flow and fully stirred, after stirring is completed, a mixture is taken out to prepare a test piece (the aggregate grading type is PAC-10), and the test piece is fully cured at room temperature.

For the high-strength room-temperature mixed pavement mixture (example 1, example 2, example 3) of the present application, test pieces were formed, maintained, and performance tested according to the test procedures for road engineering asphalt and asphalt mixture (JTG E20-2011), and compared with the high-viscosity modified asphalt PAC-10 mixture, and the results are shown in table 1.

Table 1 Performance test results of room temperature mixed pavement mixture with 7d curing age

According to experimental results, compared with a high-viscosity modified asphalt PAC-10 mixture, the high-strength room-temperature mixed pavement mixture has the advantages that the freeze-thaw splitting strength ratio is kept constant after full maintenance, the dynamic stability of the high-strength room-temperature mixed pavement mixture is improved by more than 4 times, the water immersion scattering loss rate is reduced by more than 40%, and the splitting tensile strength and the freeze-thaw splitting strength are improved by more than 2 times. Compared with the comparative example 2 (the scheme without cement), the water immersion scattering loss rate is reduced by more than 40%, and the splitting tensile strength and the freeze-thaw splitting strength are improved by more than 20%. The invention has excellent high-temperature performance and low-temperature performance, and obviously improves the water stability and the strength of the mixture.

Similarly, the dipping and scattering test of the mixture was carried out at different curing ages, and the results are shown in Table 2.

Table 2 loss rate in the water-soaking and fly-off test of the mixture at various curing times (%)

Compared with the high-viscosity modified asphalt PAC-10 mixture, the strength and the bonding strength of the room-temperature mixed pavement mixture are lower in the early stage of curing, but the water-soaking scattering loss is obviously reduced due to the curing of polyurethane and the hydration of cement in the later stage, the water-soaking scattering loss is only less than 60% of that of a control mixture, and the water stability is obviously improved.

In conclusion, the high-strength room-temperature mixed pavement mixture disclosed by the invention has high strength and excellent pavement performance, can greatly reduce the energy consumption and the emission of harmful smoke during room-temperature construction, and can be used as an environment-friendly pavement material for heavy-duty traffic pavements.

Claims (9)

1. The room-temperature mixing road surface mixture comprises mineral aggregate, emulsified asphalt, aqueous polyurethane emulsion, cement, a defoaming agent and a retarder, wherein the emulsified asphalt, the aqueous polyurethane emulsion, the cement, the defoaming agent and the retarder form a cementing material, and the mineral aggregate comprises coarse aggregate, fine aggregate and filler; 8 to 15 parts of cementing material and 100 parts of mineral material by weight; 100 parts of emulsified asphalt, 60-80 parts of aqueous polyurethane emulsion, 1-18 parts of cement, 1-3 parts of defoamer and 0-0.3 part of retarder, wherein the aqueous polyurethane emulsion is an emulsion or dispersion of aqueous polyurethane, and the solid content of the aqueous polyurethane emulsion is 30-50%.

2. The room temperature mixing pavement mixture of claim 1, wherein the coarse aggregate is basalt or diabase, and the fine aggregate and filler are limestone.

3. The room-temperature mixing dough mixture according to claim 1, wherein the nominal particle size δ of the coarse aggregate is greater than 4.75mm, the nominal particle size δ of the fine aggregate is greater than 0.075mm and less than δ and less than or equal to 4.75mm, and the nominal particle size δ of the filler is less than or equal to 0.075mm.

4. The room temperature mixing pavement mixture of claim 1, wherein the emulsified asphalt is at least one of cationic emulsified asphalt, anionic emulsified asphalt and nonionic emulsified asphalt.

5. The room-temperature mixing road surface mixture according to claim 1, wherein the solid content of the emulsified asphalt is more than or equal to 50%.

6. The room-temperature mixing road surface mixture according to claim 1, wherein the cement is at least one of ordinary portland cement with a strength grade of 52.5 and 52.5R and road portland cement with a strength grade of 52.5.

7. The room temperature mixing dough mixture of claim 1, wherein the defoamer is at least one of mineral oil, dimethicone, stearic acid, and monolauryl butyl stearate.

8. The room-temperature mixing pavement mixture according to claim 1, wherein the retarder is at least one of acetic acid, tartaric acid and an oxyphosphate compound with surface activity.

9. The method for preparing the room temperature mix road surface mixture of any one of claims 1 to 8, comprising the following steps:

step 1) fully drying the screened mineral aggregate and the cement powder for later use;

step 2) placing the coarse aggregate and the fine aggregate with the grain size larger than 0.6mm into a stirring pot, adding the waterborne polyurethane emulsion, the defoaming agent and the retarder, and stirring for 40-60s at room temperature;

step 3) adding fine aggregates with the particle size of less than or equal to 0.6mm and fillers, and continuously stirring for 60-90s;

and 4) adding emulsified asphalt and cement, and continuously stirring for 60-90s to obtain the pavement mixture.

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