A functional polyurethane exposed-aggregate pavement and its preparation method

Abstract

The present invention relates to the technical field of pavement construction, especially in the IPC E01C7 field. More specifically, it relates to a functional polyurethane exposed-aggregate pavement and its preparation method. The components include: binder, aggregate, and surface flushing agent; the binder includes polyurethane. The melting temperature of the polyurethane is 280 - 320 °C, the tensile strength is 15 - 25 MPa, and the elongation at break is 180 - 300%, which can improve the bonding performance and anti-slip performance, and at the same time has excellent bonding effect with the original pavement structure and the underlying layer; the aggregate includes a first aggregate and a second aggregate, the particle size of the first aggregate is 3 - 9.5 mm, the particle size of the second aggregate is 9.5 - 15 mm, and the weight ratio of the first aggregate to the second aggregate is (2 - 4):(6 - 8), which can further improve the strength, anti-slip performance, and performance at high and low temperatures of the pavement.

Description

Technical Field

[0001] The present invention relates to the technical field of pavement construction, especially in the IPC E01C7 field. More specifically, it relates to a functional polyurethane exposed-aggregate pavement and its preparation method. Background Art

[0002] During the construction of expressways, due to the high speed of vehicle travel, the expressway pavement is required to have excellent anti-slip and anti-glare functions. Exposed-aggregate concrete has excellent anti-slip, noise reduction, anti-glare and drainage functions. The preparation of existing exposed-aggregate concrete pavements includes: after the surface layer of cement concrete is poured and vibrated, a certain period of time is reserved, and then a certain amount of exposed-aggregate agent is sprayed on its surface, the physical and chemical treatment of the thin surface layer of cement mortar is carried out, and then the pavement is washed away.

[0003] CN114835450A discloses a high-performance exposed-aggregate concrete for expressway pavement and its construction method. Its raw materials include 126 kg / m 3 of water, 370 kg / m 3 of low-heat portland cement, 703 kg / m 3 of river sand with a particle size not greater than 2.36 mm, 1251 kg / m 3 of non-alkali-active crushed stone with a particle size of 9.5 mm to 13.2 mm, 9.25 kg / m 3 of a retarding type high-efficiency air-entraining water reducer, thereby significantly improving the anti-slip performance and noise reduction performance of the exposed-aggregate concrete pavement.

[0004] CN111187044B discloses an exposed-aggregate concrete and its construction method, which is made of the following parts by weight of exposed-aggregate concrete raw materials: 250 - 300 parts of cement, 1100 - 1200 parts of coarse aggregate, 750 - 850 parts of fine aggregate, 80 - 120 parts of mineral powder, 8 - 12 parts of water reducer, 140 - 180 parts of water; the construction method of the exposed-aggregate concrete includes the following steps: preparation of exposed-aggregate agent, preparation of concrete, pavement pouring, pavement maintenance.

[0005] CN103232218B discloses a high-performance concrete exposed-aggregate agent and its preparation and application method. Using an exposed-aggregate agent containing fluorosilicate and organic phosphorus improves the setting retardation efficiency of the exposed-aggregate agent, reduces the dosage of the exposed-aggregate agent, and is used to prepare exposed-aggregate concrete, improving the anti-slip and drainage performance of the exposed-aggregate concrete. Fluorosilicate is not environmentally friendly and brings certain harm to the construction environment of the exposed-aggregate concrete.

[0006] Due to the use of cement as a binder in the above-mentioned technology, the color of cement concrete is light and the glare is serious. At the same time, the construction technology of cement pavement is complex, and vibration, water collection and surface finishing are required to control the flatness, which directly affects the exposed aggregate effect. The curing time of concrete pavement is long and the construction technology is relatively complex. In addition, due to its large stiffness, saw cuts are required to avoid shrinkage cracks, resulting in poor driving comfort. Also, due to the poor adhesion between cement materials and aggregates themselves, phenomena such as loose particles are likely to occur after forming. Summary of the Invention

[0007] In the first aspect of the present invention, a functional polyurethane exposed aggregate pavement is provided, and the components include: a binder, aggregates, and a surface flushing agent.

[0008] The applicant's research found that the binder includes polyurethane, the melting temperature of the polyurethane is 280 - 320 °C, the tensile strength is 15 - 25 MPa, and the elongation at break is 180 - 300%, which can improve the bonding performance and anti-slip performance. Especially when compounded with two kinds of aggregates with particle sizes of 4.75 - 9.5 mm and 9.5 - 13.2 mm and a weight ratio of (2 - 4):(6 - 8), the strength, anti-slip performance and performance at high and low temperatures of the pavement can be further improved. When the two kinds of aggregates are proportionally compounded, the large-particle aggregates can play a role in anti-slip and skeleton support, and the small-particle aggregates can appropriately fill the voids, reducing the collapse caused by too large voids. If the voids are too large, it is difficult for the binder to adhere the aggregates, and rainwater is more likely to enter the road structure, peeling the interface between the aggregates and the binder, causing serious water damage to the pavement, thereby greatly reducing the service life of the road, resulting in a decrease in strength. At the same time, the specific proportion of aggregate compounding forms a rigid skeleton that restricts the shrinkage of the binder, thereby improving the performance of the pavement under high and low temperature conditions, enhancing the weather resistance of the pavement, and also improving the dispersion performance of the system and shortening the dispersion time. It may be that polyurethane has extremely strong bonding performance and can better match with acidic granite aggregates, so that the aggregates can be well wrapped by polyurethane. At the same time, the price of acidic granite is relatively low. Generally, the performance of road aggregates is better for limestone and basalt, but their prices are very high.

[0009] The binder includes polyurethane, the melting temperature of the polyurethane is 280 - 320 °C, the tensile strength is 15 - 25 MPa, and the elongation at break is 180 - 300%.

[0010] Preferably, the binder includes one-component polyurethane, the melting temperature of the polyurethane is 290 - 320 °C, the tensile strength is 15 - 20 MPa, and the elongation at break is 180 - 230%.

[0011] Further preferably, the binder comprises one-component polyurethane. The melting temperature of the polyurethane (test data reference: GB / T 19250) is 309.7 °C, the tensile strength is 18.6 MPa, the elongation at break is 210%, and the one-component polyurethane is purchased from Wanhua Chemical Group Co., Ltd.

[0012] The aggregate comprises at least one of granite, basalt, rhyolite, and limestone.

[0013] Preferably, the aggregate comprises acidic granite.

[0014] The aggregate comprises a first aggregate and a second aggregate. The particle size of the first aggregate is 3 - 9.5 mm, and the particle size of the second aggregate is 9.5 - 15 mm.

[0015] Preferably, the aggregate comprises a first aggregate and a second aggregate. The particle size of the first aggregate is 4.75 - 9.5 mm, and the particle size of the second aggregate is 9.5 - 13.2 mm.

[0016] The weight ratio of the first aggregate to the second aggregate is (2 - 4):(6 - 8).

[0017] Preferably, the weight ratio of the first aggregate to the second aggregate is 3:7.

[0018] The weight percentage of the binder in the aggregate is 2.5 - 6.

[0019] Preferably, the weight percentage of the binder in the aggregate is 4.8.

[0020] The surface flushing agent comprises at least one of methyl ethyl ketone, acetone, ethyl acetate, dimethylacetamide, and butyl acetate.

[0021] Preferably, the surface flushing agent comprises acetone and ethyl acetate, and the weight ratio of acetone to ethyl acetate is (13 - 15):(5 - 7).

[0022] Further preferably, the surface flushing agent comprises acetone and ethyl acetate, and the weight ratio of acetone to ethyl acetate is 7:3.

[0023] The second aspect of the present invention provides a preparation method for a functional polyurethane exposed-aggregate pavement, comprising the following steps:

[0024] S1. Mix the binder and the aggregate, and after paving and rolling, wait for 3 - 5 h to cure and form.

[0025] S2. Spray the surface flushing agent on the cured surface for soaking.

[0026] S3. Sweep and wash to expose the aggregate, and then it is obtained.

[0027] The mixing of the binder and the aggregate specifically includes: the aggregate is conveyed into the mixing pan after being dedusted and dried by a conveyor belt, and polyurethane is sprayed in and stirred for 2 - 3 minutes at a stirring speed of 60 - 70 rpm.

[0028] Preferably, the mixing of the binder and the aggregate specifically includes: the aggregate is conveyed into the mixing pan after being dedusted and dried by a conveyor belt, and polyurethane is sprayed in and stirred for 3 minutes at a stirring speed of 60 rpm.

[0029] The spraying amount is 0.12 - 0.20 kg / m 2 。

[0030] Preferably, the spraying amount is 0.15 kg / m 2 。

[0031] The soaking time is 5 - 20 minutes.

[0032] Preferably, the soaking time is 10 minutes.

[0033] The depth of the exposed aggregate is 2 - 3.5 mm.

[0034] Preferably, the depth of the exposed aggregate is 2.5 mm.

[0035] The thickness of the exposed aggregate pavement is 3.5 - 5 cm.

[0036] Preferably, the thickness of the exposed aggregate pavement is 4 cm.

[0037] Beneficial effects:

[0038] 1. The binder includes polyurethane, and the melting temperature of the polyurethane is 280 - 320 °C, the tensile strength is 15 - 25 MPa, and the elongation at break is 180 - 300%. It can improve the bonding performance, service life, and anti-slip performance, and at the same time has an excellent bonding effect with the original road surface structure and the underlying layer.

[0039] 2. The aggregate includes a first aggregate and a second aggregate. The particle size of the first aggregate is 3 - 9.5 mm, the particle size of the second aggregate is 9.5 - 15 mm, and the weight ratio of the first aggregate to the second aggregate is (2 - 4):(6 - 8), which can further improve the strength, anti-slip performance, and performance at high and low temperatures of the road surface.

[0040] 3. The spraying amount is 0.12 - 0.20 kg / m 2 , the soaking time is 5 - 20 minutes, which can improve the paving efficiency of the road surface, and at the same time improve the anti-slip performance and driving comfort. If the spraying amount of the flushing agent is insufficient, it cannot be soaked and dissolved to reach the required exposed aggregate depth, resulting in a reduction in anti-slip performance. If the soaking time is insufficient, the dissolution effect is not enough, the surface is uneven, and the exposed aggregate depth is insufficient.

[0041] 4. The surface flushing agent includes acetone and ethyl acetate, and the weight ratio of acetone to ethyl acetate is (13 - 15):(5 - 7), which can reduce the reaction time, improve the uniformity of the exposed stone surface, control the depth of the exposed aggregates, and improve the water damage resistance and fatigue life.

[0042] 5. Acidic aggregate granite is used in combination with polyurethane. The thickness of the exposed stone pavement is 3.5 - 5 cm, which enables the pavement color to be adjustable, the performance to be designed, the construction process to be simple, the service life to be long, and the maintenance cycle to be long. However, the overall pavement structure is too low, the overall strength is reduced, and it is not easy to carry out rolling construction during construction due to the thin thickness of the structural layer, and it is extremely easy to be displaced.

[0043] 6. The weight percentage of the binder in the aggregates is 2.5 - 6, which can improve the strength and high and low temperature performance. If the amount of the binder is too low, it cannot completely wrap the surface of the granite, and the aggregate particles are likely to be loose and fall off due to insufficient amount of the binder. Detailed implementation mode

[0044] Example 1

[0045] A functional polyurethane exposed stone pavement, the components are: binder, aggregates, surface flushing agent.

[0046] The binder is a one - component polyurethane. The melting temperature of the polyurethane (test data reference: GB / T19250) is 309.7 °C, the tensile strength is 18.6 MPa, and the elongation at break is 210%. The one - component polyurethane is purchased from Wanhua Chemical Group Co., Ltd., model 6750F

[0047] The aggregates are acidic granite. The acidic granite is the first aggregate and the second aggregate. The particle size of the first aggregate is 4.75 - 9.5 mm, the particle size of the second aggregate is 9.5 - 13.2 mm, and the weight ratio of the first aggregate to the second aggregate is 3:7.

[0048] The weight percentage of the binder in the aggregates is 4.8.

[0049] The surface flushing agent is acetone and ethyl acetate, and the weight ratio of acetone to ethyl acetate is 7:3.

[0050] A preparation method of a functional polyurethane exposed stone pavement is the following steps:

[0051] S1. Mix the binder and the aggregates, after paving and rolling, wait for 4 h to cure and form;

[0052] S2. Spray the surface flushing agent on the cured surface for soaking;

[0053] S3. Scrub and wash to expose the aggregates, then it is obtained.

[0054] The specific steps for mixing the binder and aggregates are as follows: The aggregates are conveyed into the mixing pan by a conveyor belt after dust removal and drying, and polyurethane is sprayed in and stirred for 3 minutes at a stirring speed of 60 rpm.

[0055] The spraying amount is 0.15 kg / m 2 , the soaking time is 10 minutes, and the depth of exposing the aggregates is 2.5 mm.

[0056] The thickness of the exposed-aggregate pavement is 4 cm.

[0057] Comparative Example 1

[0058] The specific implementation method is the same as that of Example 1; the difference is that in Comparative Example 1: the aggregates are acidic granite, and the particle size of the acidic granite is 9.5 - 13.2 mm.

[0059] Comparative Example 2

[0060] The specific implementation method is the same as that of Example 1; the difference is that in Comparative Example 2: the weight ratio of acetone to ethyl acetate is 1:1.

[0061] Comparative Example 3

[0062] The specific implementation method is the same as that of Example 1; the difference is that in Comparative Example 3: the surface rinsing agent is methanol.

[0063] Comparative Example 4

[0064] The specific implementation method is the same as that of Example 1; the difference is that in Comparative Example 4: the surface rinsing agent is butyrolactam.

[0065] Comparative Example 5

[0066] The specific implementation method is the same as that of Example 1; the difference is that in Comparative Example 5: the dosage of polyurethane is 3%.

[0067] Comparative Example 6

[0068] The specific implementation method is the same as that of Example 1; the difference is that in Comparative Example 6: the spraying amount of the rinsing agent is 0.1 kg / m 2 .

[0069] Comparative Example 7

[0070] The specific implementation method is the same as that of Example 1; the difference is that in Comparative Example 7: the soaking time after spraying the rinsing agent is 5 minutes.

[0071] Comparative Example 8

[0072] The specific implementation method is the same as that of Example 1; the difference is that in Comparative Example 8: the thickness of the polyurethane exposed aggregate pavement is 3 cm.

[0073] Performance testing method

[0074] Perform performance tests on the examples and comparative examples, and the test data are listed in Table 1.

[0075] 1. Uniaxial penetration strength (high-temperature performance): Refer to JTG D50-2017.

[0076] 2. Exposed aggregate depth: The exposed height of the aggregate after flushing.

[0077] 3. Low-temperature crack resistance: Low-temperature beam bending test (JTG T0715).

[0078] 4. Resistance to water damage: Freeze-thaw splitting test (JTG T0729).

[0079] 5. Fatigue life: Four-point bending fatigue test (JTG T0739).

[0080] 6. Pavement friction coefficient BPN: Refer to T0964.

[0081] 7. Surface texture depth TD: Refer to T0961.

[0082] Performance test data

[0083] Table 1

[0084]

[0085]

[0086]

Claims

1. A functional polyurethane exposed-aggregate pavement, characterized in that, the components include: binder, aggregate, surface flushing agent; the binder includes polyurethane; the binder includes polyurethane, the melting temperature of the polyurethane is 280 - 320 °C, the tensile strength is 15 - 25 MPa, the elongation at break is 180 - 300%, the aggregate includes first aggregate and second aggregate, the particle size of the first aggregate is 3 - 9.5 mm, the particle size of the second aggregate is 9.5 - 15 mm, and the weight ratio of the first aggregate to the second aggregate is (2 - 4):(6 - 8); the surface flushing agent includes acetone and ethyl acetate, and the weight ratio of acetone to ethyl acetate is (13 - 15):(5 - 7).

2. The functional polyurethane exposed-aggregate pavement according to claim 1, characterized in that, the aggregate includes at least one of granite, basalt, rhyolite, and limestone.

3. The functional polyurethane exposed-aggregate pavement according to claim 1 or 2, characterized in that, the weight percentage of the binder in the aggregate is 2.5 - 6.

4. A preparation method of the functional polyurethane exposed-aggregate pavement according to claim 1, characterized in that, it includes the following steps: S1, mix the binder and the aggregate, after paving and rolling, wait for 3 - 5 h to cure and form; S2, spray the surface flushing agent on the cured surface for soaking; S3, sweep and wash to expose the aggregate, thus obtaining.

5. The preparation method of the functional polyurethane exposed-aggregate pavement according to claim 4, characterized in that, The amount of spraying is 0.12 - 0.20 kg / m 2 .

6. The preparation method of the functional polyurethane exposed-aggregate pavement according to claim 5, characterized in that, the soaking time is 5 - 20 min.

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