Sound absorption and noise reduction type diatomite filler porous polyurethane pavement material as well as preparation method and application thereof

Abstract

The invention relates to a sound absorption and noise reduction type diatomite filler porous polyurethane pavement material and a preparation method and application thereof.The sound absorption and noise reduction type diatomite filler porous polyurethane pavement material is prepared from a polyurethane cementing material, diatomite and graded aggregate, the modifier accounts for 1-2% of the mass of the polyurethane, the mass ratio of the polyurethane cementing material to the graded aggregate is (0.045-0.065): 1, and the mass ratio of the diatomite to the graded aggregate is (0.04-0.1): 1. The preparation method comprises the following steps: mixing polyurethane with a modifier to obtain a polyurethane cementing material; and uniformly mixing the polyurethane cementing material, the diatomite and the graded aggregate, compacting in a mold by using a compactor, and curing to obtain the product. Compared with the prior art, the pavement material prepared by the invention has a higher average sound absorption coefficient in a frequency range of 200-2000Hz, and the durability is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of road engineering, and in particular to a porous polyurethane pavement material with sound absorption and noise reduction type diatomite filler, its preparation method and application. Background Technique

[0002] With the increasing demand for road traffic travel and the sharp increase in the number of motor vehicles, traffic noise pollution has become one of the main problems in urban environmental governance. Among them, the interaction between the tire and the road surface is the main source of traffic noise, accounting for more than 70% of the road traffic noise. With the progress of automobile manufacturing technology, the noise of power systems such as engines has been further reduced, and the importance of effectively controlling noise from the sound source has gradually emerged. Therefore, noise reduction pavements have become an economical and effective measure to control road noise.

[0003] Traditional noise reduction pavement materials (such as porous asphalt mixtures) change the acoustic impedance of the pavement structure through the void structure, and to a certain extent reduce the tire-road surface noise level. The contact between the aggregate of the porous mixture changes from full-area contact to point contact state, and the rich void structure and the limited contact area of the aggregate put forward higher requirements for the adhesiveness and high and low temperature performance of the binder. The asphalt material with high temperature sensitivity causes diseases such as rutting, cracking, and water damage to easily occur in the porous asphalt pavement, affecting the service life and functional characteristics of the porous pavement. In addition, restricted by the performance of the asphalt material, it is difficult to increase the porosity of the porous asphalt mixture, resulting in a narrow sound absorption frequency range, and it is easily affected by problems such as pore blockage, aging, and spalling during long-term use, resulting in the attenuation of the noise reduction effect. Summary of the Invention

[0004] The purpose of the present invention is to provide a porous polyurethane pavement material with sound absorption and noise reduction type diatomite filler, its preparation method and application in order to overcome the problems existing in the prior art such as insufficient noise reduction performance and poor durability.

[0005] The purpose of the present invention can be achieved through the following technical solutions:

[0006] One of the technical solutions of the present invention is to provide a porous polyurethane pavement material with sound absorption and noise reduction type diatomite filler, which includes a polyurethane binder, diatomite and graded aggregate. The polyurethane binder includes polyurethane and a modifier, and the modifier is 1-2% of the mass of the polyurethane. The mass ratio of the polyurethane binder to the graded aggregate is (0.045-0.065):1, and the mass ratio of the diatomite to the graded aggregate is (0.04-0.1):1.

[0007] The sound-absorbing and noise-reducing diatomite porous polyurethane pavement material of the present invention utilizes the characteristics of high bonding strength of polyurethane binder, smooth pore interface formed with aggregates, and enhanced sound absorption of diatomite microporous structure, and combines the best preparation process parameters to significantly improve the noise reduction effect of porous pavement, especially having significant advantages in high-frequency noise absorption and long-term road performance.

[0008] In some specific embodiments, the polyurethane is a one-component moisture-curing polyurethane adhesive with a tensile strength of not less than 18 MPa.

[0009] In the present invention, the selected polyurethane is a one-component moisture-curing polyurethane adhesive. Compared with two-component polyurethane adhesives, one-component polyurethane adhesives do not need to be accurately proportioned, have simple construction operation steps, and have a slower curing speed and longer construction tolerance. To ensure the durability of the low-noise pavement, the tensile strength of the one-component polyurethane adhesive is not less than 18 MPa.

[0010] In some specific embodiments, the modifier is selected from any one or more of polycarbodiimide, silane coupling agent, and epoxy resin.

[0011] In the present invention, for the selected modifier, the -N=C=N- group of polycarbodiimide can react with the carboxyl group generated by the hydrolysis of polyurethane to form a stable compound amide, preventing its further catalytic effect on the hydrolysis of the polymer, thereby inhibiting the hydrolysis of polyurethane. The silane coupling agent can significantly improve the bonding ability between mineral graded aggregates and organic polyurethane binders, and can inhibit the deterioration of the polyurethane-aggregate interface caused by moisture. After modification with epoxy resin, the crosslinking density of polyurethane increases, and the water absorption rate of polyurethane can be reduced.

[0012] In some specific embodiments, the particle size of the diatomite is 300 - 500 mesh, the density is 2.1 - 2.3 g / cm 3 , and the pH value is 7 - 10.

[0013] In the present invention, the selected diatomite has a rich microporous structure and uniform particle size distribution. The smaller bulk density can adsorb more polyurethane, increase the flow resistance rate and tortuosity factor of the porous mixture, affect the microstructure of the porous asphalt mixture, and then change the main sound absorption frequency band and sound absorption coefficient of the porous mixture, enhancing the high-frequency sound absorption ability of the pavement material, thereby reducing tire-pavement noise.

[0014] In some specific embodiments, the graded aggregate is basalt, and the particle size distribution of the graded aggregate is such that the aggregate passing rate (the ratio of the passing mass to the total mass) corresponding to the 0.075 mm sieve hole is 3-6%, the aggregate passing rate corresponding to the 0.15 mm sieve hole is 4-9%, the aggregate passing rate corresponding to the 0.3 mm sieve hole is 5-12%, the aggregate passing rate corresponding to the 0.6 mm sieve hole is 6-14%, the aggregate passing rate corresponding to the 1.18 mm sieve hole is 7-17%, the aggregate passing rate corresponding to the 2.36 mm sieve hole is 9-20%, the aggregate passing rate corresponding to the 4.75 mm sieve hole is 10-30%, the aggregate passing rate corresponding to the 9.5 mm sieve hole is 40-71%, the aggregate passing rate corresponding to the 13.2 mm sieve hole is 90-100%, and the aggregate passing rate corresponding to the 16 mm sieve hole is 100%.

[0015] The second technical solution of the present invention is to provide a preparation method of a sound-absorbing and noise-reducing diatomite-filled porous polyurethane pavement material as described in one of the above technical solutions, comprising the following steps:

[0016] S1. Mix polyurethane and a modifier, and degas to obtain a polyurethane binder;

[0017] S2. Mix dry diatomite and graded aggregate, and add the polyurethane binder obtained in step S1 to mix, to obtain a polyurethane porous mixture;

[0018] S3. Compact and mold the polyurethane porous mixture obtained in step S2, and cure to obtain a sound-absorbing and noise-reducing diatomite-filled porous polyurethane pavement material.

[0019] In some specific embodiments, in step S1, the degassing is carried out by a vacuum degassing process, the temperature is 80-100 °C, the vacuum degree is -0.1 MPa, and the time is 4-5 h.

[0020] In some specific embodiments, in step S2, the water contents of the dry diatomite and the graded aggregate are both less than 0.1%; the porosity of the polyurethane porous mixture is 18-25%.

[0021] In some specific embodiments, in step S3, the curing process conditions are: temperature 25 ± 2 °C, humidity (65-75)%, and curing time (70-74) h.

[0022] More preferably, the curing process conditions are: temperature 25 °C, humidity 70%, and curing time 72 h.

[0023] The third technical solution of the present invention is to provide an application of a sound-absorbing and noise-reducing diatomite-filled porous polyurethane pavement material as described in one of the above technical solutions, and the sound-absorbing and noise-reducing diatomite-filled porous polyurethane pavement material is used for road paving.

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] (1) The greatest advantage of the present invention is that by reasonably designing diatomite and polyurethane binder and their ratio, the prepared pavement material has a higher average sound absorption coefficient in the frequency range of 200 - 2000 Hz, which is more conducive to the absorption of tire - pavement noise, and is suitable for various paving environments such as urban roads and highways. Especially in areas with higher noise control requirements, its noise reduction effect is particularly prominent.

[0026] (2) Due to the fact that the hydrolysis resistance of the polyurethane binder is greatly improved under the action of the modifier, the water stability of the pavement material prepared by the present invention is enhanced under high - humidity conditions, and the service life of the pavement is extended. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 For the water absorption rate and tensile strength of the polyurethane binders in Examples 1 - 2 and Comparative Examples 1 - 2.

[0028] Figure 2 For the comparison chart of the sound absorption coefficient frequency spectrum curves of Examples 1 - 2, Comparative Examples 1 - 2 and dense - graded asphalt mixture AC - 13 in the frequency range of 200 - 2000 Hz.

[0029] Figure 3 For the average sound absorption coefficient of Examples 1 - 2, Comparative Examples 1 - 2 and dense - graded asphalt mixture AC - 13 in the frequency range of 200 - 2000 Hz. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0030] The present invention will be described in detail below with reference to the drawings and specific embodiments. This embodiment is implemented on the premise of the technical solution of the present invention, and gives the detailed implementation manner and specific operation process, but the protection scope of the present invention is not limited to the following embodiments.

[0031] In the following examples and comparative examples, unless otherwise specified for raw materials or treatment techniques, it means that they are all conventional commercially available raw material products or conventional treatment techniques in the art.

[0032] Example 1:

[0033] This example provides a sound - absorbing and noise - reducing diatomite - filled porous polyurethane pavement material and its preparation method. In this example, the target void ratio of the polyurethane porous mixture is set to 25%.

[0034] The sound - absorbing and noise - reducing diatomite - filled porous polyurethane pavement material comprises the following raw material components:

[0035] (1) The polyurethane is a one-component moisture-curing polyurethane adhesive, a one-component polyurethane adhesive purchased from Wanhua Chemical Group Co., Ltd., and the tensile strength index tested by GB / T19250 is 23.5 MPa. The range of polyurethane dosage is determined to be 4.88% - 5.60% of the mass of the graded aggregate through the inflection points of the two curves of the fling and bleeding tests, and the optimal polyurethane dosage is finally determined to be 5.24% of the mass of the graded aggregate.

[0036] (2) The modifier is polycarbodiimide, and the dosage is 2% of the mass of the polyurethane.

[0037] (3) The diatomite is from a factory in Jilin. Its appearance is white powder, the mineral density is 0.45 g / cm 3 , the mass content of SiO2 is greater than 85%, the fineness is 300 - 500 mesh, it is non-toxic, and its main physical indicators are shown in Table 1. The dosage of diatomite is 10% of the mass of the graded aggregate.

[0038] Table 1 Main technical indicators of diatomite

[0039] Technical indicators Value <![CDATA[Density / (g·cm -3 )]]> 2.132 <![CDATA[Bulk density / (g·cm -3 )]]> 0.38 Permeability / md 2.6～3.5 Loss on ignition / % ≤0.26 Water content / % ≤0.1 pH 7.8～8.9 <![CDATA[SiO2 content / %]]> ≥88.2 <![CDATA[Fe2O3 content / %]]> ≤1.1

[0040] (4) The graded aggregate selected is basalt aggregate. Three different gradations are designed within the gradation range, and the mineral aggregate gradation is preferably determined as shown in Table 2 through tests.

[0041] Table 2 Aggregate gradation

[0042]

[0043] The preparation method of the sound-absorbing and noise-reducing diatomite-filled porous polyurethane pavement material includes the following steps:

[0044] (1) Heat and dry the diatomite and aggregate in an oven at 180 °C for 60 ± 5 min. After testing, the moisture content is less than 0.1%. Place the diatomite and aggregate indoors until cooled to room temperature (25 °C).

[0045] (2) Add polycarbodiimide accounting for 2% of the mass of the polyurethane to the polyurethane, and stir with a glass rod for 3 min until evenly mixed. Place it in a vacuum drying oven for vacuum defoaming. Set the temperature to 80 °C, the vacuum degree to -0.1 MPa, and the time to 4 h. After defoaming, cool to room temperature to obtain the polyurethane binder.

[0046] (3) Put the graded aggregate and diatomite into a mixing pot, mix at room temperature (25 °C) for 90 s, then add the polyurethane binder and mix for another 90 s to obtain the polyurethane porous mixture.

[0047] (4) Lay the polyurethane porous mixture in the Marshall specimen mold, and use the Marshall compactor to double-side compact the polyurethane porous mixture 75 times to prepare the polyurethane porous mixture specimen.

[0048] (5) Place the porous polyurethane mixture specimen together with the Marshall specimen mold in a thermostatic and humidified box for curing. The curing environmental conditions are a temperature of 25 °C, a humidity of 70%, and a curing time of 72 h. After taking it out and cooling it at room temperature to demold, the sound-absorbing and noise-reducing diatomite porous polyurethane pavement material is obtained.

[0049] Cut the specimen of the sound-absorbing and noise-reducing diatomite porous polyurethane pavement material so that the specimen diameter matches the inner diameter of the standing wave tube, which is 100 mm and 29 mm. According to the "Test Specification for Sound Absorption Coefficient and Specific Acoustic Impedance by Impedance Tube Method (GB J88 - 1985)", test its 1 / 3 octave band sound absorption coefficient in the frequency range of 50 - 2000 Hz.

[0050] Example 2:

[0051] This example provides a sound-absorbing and noise-reducing diatomite filler porous polyurethane pavement material and its preparation method. In this example, the target void ratio of the polyurethane porous mixture is set to 25%.

[0052] (1) The polyurethane is a one-component moisture-curing polyurethane adhesive, a one-component polyurethane adhesive purchased from Wanhua Chemical Group Co., Ltd., and the tensile strength index tested by GB / T19250 is 23.5 MPa. The range of polyurethane dosage is determined to be 4.68% - 5.28% of the mass of the graded aggregate through the inflection points of the two curves of the fling and bleeding tests, and the optimal polyurethane dosage is finally determined to be 5.0% of the mass of the graded aggregate.

[0053] (2) The modifier is polycarbodiimide, and the dosage is 1% of the mass of the polyurethane.

[0054] (3) The diatomite comes from a factory in Jilin. Its appearance is white powder, the mineral density is 0.45 g / cm 3 , the mass content of SiO2 is greater than 85%, the fineness is 300 - 500 mesh, non-toxic, and its main physical indexes are shown in Table 1. The diatomite dosage is 5% of the mass of the graded aggregate.

[0055] (4) The graded aggregate is selected as basalt aggregate, and three different gradations are designed within the gradation range. Through tests, the optimal aggregate gradation is determined as shown in Table 3.

[0056] Table 3 Aggregate Gradation

[0057]

[0058] The preparation method of the sound-absorbing and noise-reducing diatomite filler porous polyurethane pavement material includes the following steps:

[0059] (1) Heat and dry the diatomaceous earth and aggregate in an oven at 180 °C for 60 ± 5 min. After testing, the moisture content is less than 0.1%. Place the diatomaceous earth and aggregate indoors until cooled to room temperature (25 °C).

[0060] (2) Add 1% of polycarbodiimide based on the mass of polyurethane to the polyurethane, and stir with a glass rod for 3 min until evenly mixed. Put it into a vacuum drying oven for vacuum defoaming. Set the temperature to 80 °C, the vacuum degree to -0.1 MPa, and the time to 4 h. After defoaming, cool to room temperature to obtain the polyurethane binder.

[0061] (3) Put the graded aggregate and diatomaceous earth into a mixing pan, mix at room temperature (25 °C) for 90 s, then add the polyurethane binder and mix for another 90 s to obtain the polyurethane porous mixture.

[0062] (4) Lay the polyurethane porous mixture in the Marshall specimen mold, and use the Marshall compactor to double-side compact the polyurethane porous mixture 75 times to prepare the polyurethane porous mixture specimen.

[0063] (5) Place the polyurethane porous mixture specimen together with the Marshall specimen mold in a constant temperature and humidity chamber for curing. The curing environmental conditions are a temperature of 25 °C, a humidity of 70%, and a curing time of 72 h. After taking it out and cooling it at room temperature, demold it to obtain the sound-absorbing and noise-reducing diatomaceous earth porous polyurethane pavement material.

[0064] Cut the specimen of the sound-absorbing and noise-reducing diatomaceous earth porous polyurethane pavement material so that the specimen diameter matches the inner diameter of the standing wave tube, which is 100 mm and 29 mm. According to the "Test Specification for Sound Absorption Coefficient and Acoustic Impedance Ratio by Impedance Tube Method (GB J88 - 1985)", test its 1 / 3 octave band sound absorption coefficient in the frequency range of 50 - 2000 Hz.

[0065] Comparative Example 1:

[0066] Compared with Example 2, most of them are the same. The only difference is that the diatomaceous earth is replaced with ordinary limestone powder, and the dosage is 5%.

[0067] Comparative Example 2:

[0068] Compared with Example 2, most of them are the same. The only difference is that the modifier polycarbodiimide is omitted, and the diatomaceous earth is replaced with ordinary limestone powder, and the dosage is 5%.

[0069] Conduct the following performance tests on the materials prepared above:

[0070] (1) Conduct an immersion tensile test and a water absorption test on the polyurethane binders prepared in Examples 1 - 2 and Comparative Examples 1 - 2 to evaluate the hydrolysis resistance of different polyurethane binders. The test results are as Figure 1 shown.

[0071] It can be seen from the test results that the polyurethane binders prepared from the modified polyurethanes in Examples 1 and 2 of the present invention have lower water absorption rates and higher tensile strengths after immersion, indicating that the polyurethanes have better water resistance after modification, and can improve the water damage resistance of diatomite porous polyurethane pavement materials.

[0072] (2) The sound absorption performance of the pavement materials prepared in Examples 1-2 and Comparative Examples 1-2, as well as the dense-graded asphalt mixture AC-13, was tested, and the sound absorption coefficients are as Figures 2 - 3 shown.

[0073] The aggregate gradation composition of the dense-graded asphalt mixture AC-13 is shown in Table 4. Styrene-butadiene block copolymer (SBS) modified asphalt was used in the test, basalt was used as the aggregate, and ordinary limestone powder was used as the filler. The asphalt-aggregate ratio is 4.7%, and the void ratio is 4.1%.

[0074] Table 4

[0075]

[0076] It can be seen from the test results that, compared with Comparative Examples 1 and 2 and the dense-graded asphalt mixture AC-13, the pavement materials prepared from diatomite in Examples 1 and 2 of the present invention have higher average sound absorption coefficients in the frequency range of 200-2000 Hz, have better sound absorption performance, and are more conducive to the absorption of tire-road noise.

[0077] The above description of the embodiments is for enabling those of ordinary skill in the art in this technical field to understand and use the invention. It is obvious that those skilled in the art can easily make various modifications to these embodiments and apply the general principles described herein to other embodiments without creative efforts. Therefore, the present invention is not limited to the above embodiments, and the improvements and modifications made by those skilled in the art without departing from the scope of the present invention according to the disclosure of the present invention should be within the protection scope of the present invention.

Claims

1. A sound-absorbing and noise-reducing diatomite-filled porous polyurethane pavement material, characterized in that, It includes a polyurethane binder, diatomaceous earth and graded aggregate. The polyurethane binder includes polyurethane and a modifier, and the modifier accounts for 1-2% of the mass of the polyurethane. The mass ratio of the polyurethane binder to the graded aggregate is (0.045 - 0.065):1, and the mass ratio of the diatomaceous earth to the graded aggregate is (0.04 - 0.1):

1.

2. The sound-absorbing and noise-reducing diatomite-filled porous polyurethane pavement material according to claim 1, wherein, The polyurethane is a one-component moisture-curing polyurethane adhesive with a tensile strength of not less than 18 MPa.

3. The sound-absorbing and noise-reducing diatomite-filled porous polyurethane pavement material according to claim 1, characterized in that, The modifier is selected from any one or more of polycarbodiimide, silane coupling agent, and epoxy resin.

4. The sound-absorbing and noise-reducing diatomite-filled porous polyurethane pavement material according to claim 1, characterized in that, The particle size of the diatomaceous earth is 300 - 500 mesh, the density is 2.1 - 2.3 g / cm 3 , and the pH value is 7 - 10.

5. The sound-absorbing and noise-reducing diatomite-filled porous polyurethane pavement material according to claim 1, characterized in that, The graded aggregate is basalt, and the particle size distribution of the graded aggregate is such that the passing rate of the aggregate corresponding to the 0.075 mm sieve hole is 3 - 6%, the passing rate of the aggregate corresponding to the 0.15 mm sieve hole is 4 - 9%, the passing rate of the aggregate corresponding to the 0.3 mm sieve hole is 5 - 12%, the passing rate of the aggregate corresponding to the 0.6 mm sieve hole is 6 - 14%, the passing rate of the aggregate corresponding to the 1.18 mm sieve hole is 7 - 17%, the passing rate of the aggregate corresponding to the 2.36 mm sieve hole is 9 - 20%, the passing rate of the aggregate corresponding to the 4.75 mm sieve hole is 10 - 30%, the passing rate of the aggregate corresponding to the 9.5 mm sieve hole is 40 - 71%, the passing rate of the aggregate corresponding to the 13.2 mm sieve hole is 90 - 100%, and the passing rate of the aggregate corresponding to the 16 mm sieve hole is 100%.

6. A preparation method of a sound-absorbing and noise-reducing diatomite-filled porous polyurethane pavement material as described in any one of claims 1 to 5, characterized in that, It includes the following steps: S1. Mix and degas the polyurethane and the modifier to obtain a polyurethane binder. S2. Mix the dry diatomaceous earth and the graded aggregate, and add the polyurethane binder obtained in step S1 to mix, to obtain a polyurethane porous mixture. S3. Compact and form the polyurethane porous mixture obtained in step S2, and after curing, obtain a sound-absorbing and noise-reducing diatomaceous earth porous polyurethane pavement material.

7. The preparation method according to claim 6, characterized in that, In step S1, the degassing adopts a vacuum degassing process, with a temperature of 80 - 100 °C, a vacuum degree of -0.1 MPa, and a time of 4 - 5 h.

8. The preparation method according to claim 6, characterized in that, In step S2, the water content in the dry diatomaceous earth and the graded aggregate is less than 0.1%; the porosity of the polyurethane porous mixture is 18 - 25%.

9. The preparation method according to claim 6, characterized in that, In step S3, the curing process conditions are: temperature 25 ± 2 °C, humidity (65 - 75)%, and curing for (70 - 74) h.

10. Application of the sound-absorbing and noise-reducing diatomite-filled porous polyurethane pavement material according to any one of claims 1 to 5, characterized in that, The sound-absorbing and noise-reducing diatomaceous earth filler porous polyurethane pavement material is used for road paving.

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