A highly elastic colloidal material for a pavement transition layer

Abstract

The present invention provides a highly elastic colloidal material for a pavement transition layer, which is composed of rubber particles, asphalt, and fibers. The rubber particles interact with the asphalt, causing the volume of the rubber particles to expand. Using scanning electron microscope image processing technology, the volume expansion rate and volume filling rate of the rubber particles are determined, and the volume of the asphalt interacting with the rubber particles is calculated. An asphalt film with a certain thickness is formed by the adsorption of asphalt on the surface of the fibers. After the fibers adsorb the asphalt, they fill the voids after the expansion of the rubber particles, and the remaining space is filled with asphalt. The volume of the asphalt adsorbed by the fibers and the volume of the fibers are calculated, and the volume of the asphalt filling the remaining space is calculated. The volume of the asphalt in the total highly elastic colloidal material is calculated. According to the calculated volumes of the rubber particles, asphalt, and fibers, combined with the densities of the rubber particles, asphalt, and fibers, the incorporation amounts of each component of the highly elastic colloidal material per 1 m 3 are calculated. The present invention effectively controls the incorporation ratios of asphalt, fibers, and rubber particles in the highly elastic colloidal material through the volume parameter relationship.

Description

Technical Field

[0001] The invention relates to the field of new materials for road engineering technology, and in particular to a high-elastic colloid material for a road surface transition layer. Background Art

[0002] With the rapid development of society and people's demand for a better life, the per capita car ownership in my country has increased year by year, and the road load has become increasingly heavier. Asphalt pavement has become the main pavement form in my country's highway projects due to its smooth surface, high comfort, short construction period, convenient maintenance and renewable utilization. Frequent severe weather continues to impact the service life of the pavement. Under the influence of the climate environment and high-intensity driving loads, the pavement still has many diseases during its service. The most typical disease is pavement cracking. According to statistics, pavement cracking accounts for more than 60% of the entire pavement disease. If it is not treated, the secondary diseases caused by it, such as potholes and subsidence, will seriously affect the service life of the pavement and driving safety.

[0003] For a long time, my country's asphalt pavement has always been designed with the concept of "strong base and thin surface". The water-stable cement pavement base has high early strength, good plate properties, and strong diffusion stress, and has always been synonymous with "strong base". Water-stable cement will shrink due to humidity and temperature. The cracks in the water-stable cement base and the secondary diseases caused by it have always been a global problem. The cracks in the pavement caused by the cracks in the water-stable cement have not been effectively solved. With the advancement of technology, more and more scholars have proposed the concept of long-life pavement. Thickening the thickness of asphalt pavement and setting a deformation capacity transition layer inside the pavement structure layer have become the focus of improving the service life and service quality of asphalt pavement.

[0004] Setting a transition layer with good deformation ability inside the pavement structure layer can delay the upward transmission of pavement cracking, and the cost is relatively low. It is a cost-effective method. At present, the transition layer includes modified asphalt stress absorption layer, sand-type asphalt mixture, high-viscosity and high-elasticity modified asphalt mixture, etc. It mainly adopts high oil-stone ratio, high-performance asphalt and fine aggregate to prepare asphalt mixture, which is paved in the pavement structure layer. The thickness of this transition layer is generally thin. It is paved according to the asphalt mixture construction process. The temperature dissipates quickly during the construction process, and the compaction is insufficient, making it difficult for the transition layer to absorb stress. At the same time, because it is an asphalt mixture type material, it is affected by the interface between stone and asphalt, its own deformation ability is limited, there are certain gaps inside, and the bonding strength between the upper and lower layers is not high.

[0005] On the other hand, with the growth of car ownership, the number of discarded tires is increasing day by day. Stacking and burning them are not conducive to green development and are called "black pollution". In recent years, processing and grinding discarded tires into fine rubber particles for use is in line with the "sustainable development" principle advocated by my country and has broad application prospects.

[0006] Therefore, it is necessary to propose a highly elastic colloidal material for the pavement transition layer, which utilizes waste tires and can ensure a large deformation capacity, strong adhesion between the upper and lower layers of the pavement, and is used in the pavement transition layer to improve the durability of the pavement structure. Summary of the Invention

[0007] Aiming at the problems in the bonding, deformation, and fluidity control of the highly elastic colloidal material for the pavement transition layer during use, the present invention aims to provide a highly elastic colloidal material with good deformation coordination, strong adhesion, and good fluidity. By absorbing asphalt with rubber particles to increase viscosity, incorporating fibers to increase toughness, and analyzing the volume change under the microscopic action of asphalt and rubber particles through scanning electron microscope image processing technology, the amount of asphalt acting with rubber particles is determined, and the film-forming state of the fiber adsorbed asphalt is determined to determine the amount of asphalt acting with the fiber. Through the volume parameter relationship, the incorporation ratios of asphalt, fiber, and rubber particles in the highly elastic colloidal material are effectively controlled, giving full play to the excellent performance of each component of the material, and recycling the rubber particles to achieve low-carbon environmental protection.

[0008] The technical problems to be solved by the present invention are achieved by the following technical solutions:

[0009] A highly elastic colloidal material for a pavement transition layer, comprising the following steps:

[0010] (1) The highly elastic colloidal material is composed of rubber particles, asphalt, and fibers. The rubber particles interact with the asphalt, causing the volume of the rubber particles to expand. Using scanning electron microscope image processing technology, the volume expansion rate and volume filling rate of the rubber particles are determined. According to the volume filling rate, the volume of rubber particles in 1 m 3 of the highly elastic colloidal material is calculated, and according to the volume expansion rate, the volume of asphalt interacting with the rubber particles is calculated;

[0011] (2) The fiber surface adsorbs asphalt to form an asphalt film with a certain thickness. After the fiber adsorbs asphalt, it fills the voids after the expansion of the rubber particles, and the remaining space is filled with asphalt. According to the thickness of the asphalt film and the specific surface area of the fiber, the volume ratio of the fiber to the asphalt adsorbed by the fiber is determined. Combining the void volume filled after the fiber adsorbs asphalt, the volume of asphalt adsorbed by the fiber and the volume of the fiber are calculated. According to the volume filling material of the space after the fiber adsorbs asphalt, the volume of asphalt filling the remaining space is calculated;

[0012] (3) The asphalt includes three parts: asphalt interacting with rubber particles, asphalt adsorbed by fibers, and asphalt filling the final voids. The volume of asphalt in the total highly elastic colloidal material is calculated;

[0013] (4) According to the calculated volumes of rubber particles, asphalt, and fibers, combined with the densities of rubber particles, asphalt, and fibers, the incorporation amounts of rubber particles, asphalt, and fibers in 1 m 3 of the highly elastic colloidal material are calculated.

[0014] Further technology of the present invention:

[0015] Preferably, for the scanning electron microscope image processing technology, the asphalt is heated to 160 - 170 °C, the rubber particles and the asphalt are mixed at a volume ratio of 2:8, sheared by a shearer for 2 h, and after standing for 24 h, the sample is taken out. Using the scanning electron microscope image recognition technology, the number of rubber particles in the sample is recognized, and by using the grid method, the scanning electron microscope image is divided into grids, and the area of the grid occupied by the rubber particles and the area of the circumscribed rectangle of the rubber particles are statistically calculated, and the volume expansion rate and volume filling rate are determined according to the following formula:

[0016] S i = i × G0

[0017]

[0018]

[0019]

[0020] In the formula: S i —— Area of a single rubber particle recognized by the scanning electron microscope image, μm 2 ; i—— Number of grids occupied by rubber particles in the scanning electron microscope image; G0—— Area of a single grid, μm 2 ; γ—— Volume expansion rate of rubber particles, %; β—— Volume filling rate of rubber particles, %; n—— Number of particles recognized by the scanning electron microscope image; D—— Diameter of rubber particles, mm; J i —— Area of the circumscribed rectangle of rubber particles in the scanning electron microscope image, μm 2 ; P f —— Volume of rubber particles in 1 m 3 of the high-elastic colloid material, m 3 .

[0021] Preferably, calculate the volume of asphalt adsorbed by the fiber and the volume of the fiber according to the following formula:

[0022]

[0023] P g1 = P x × u × SA × ρ x

[0024] P x + P g1 + P g3 = 1 - P f × (1 + γ)

[0025] P g3 = (1 - α) × (1 - Pf ×(1 + γ))

[0026] Where: P g1 —— The volume of asphalt interacting with fibers in the high-elastic colloidal material, m 3 ; P x —— The volume of fibers in the high-elastic colloidal material, m 3 ; u—— The thickness of the asphalt film on the fiber surface, um; SA—— The specific surface area of the fiber, m 2 / kg; ρ x —— The density of the fiber, kg / m 3 ; r—— The diameter of the fiber particles, mm; P g3 —— The volume of asphalt filling the final voids, m 3 ; α—— The space volume filling rate of the spheres formed after the fibers adsorb asphalt, taking 52.3%.

[0027] Preferably, the asphalt includes three parts: asphalt interacting with rubber particles, asphalt adsorbed by fibers, and asphalt filling the final remaining voids. The asphalt dosage is calculated according to the following formula:

[0028] P g2 = P f ×γ

[0029] P g = P g1 + P g2 + P g3

[0030] Where: P g —— The volume of asphalt in the high-elastic colloidal material, m 3 ; P g2 —— The volume of asphalt interacting with rubber particles in the high-elastic colloidal material, m 3 .

[0031] Preferably, the proportion of raw materials incorporated into the high-elastic colloidal material is calculated according to the following formula:

[0032] m f = P f ×ρ f

[0033] m x = P x ×ρ x

[0034] m g = P g ×ρ g

[0035] Where: m f —— The dosage of rubber particles in 1m 3 of the colloidal material, kg; mx —— 1 m 3 Dosage of fiber in the colloidal material, kg; m g —— 1 m 3 Dosage of asphalt in the colloidal material, kg; ρ f —— Density of rubber particles, kg / m 3 ; ρ g —— Density of asphalt, kg / m 3 .

[0036] Preferably, the fiber in the high-elastic colloidal material is granular fiber with a fiber diameter of 0.2 - 0.4 mm, and the rubber particles are 30 - 50 mesh.

[0037] Preferably, the asphalt in the high-elastic colloidal material is SBS modified asphalt, and the thickness of the asphalt film formed by the fiber adsorbing asphalt is 15 - 25 μm.

[0038] The beneficial effects of the present invention are:

[0039] The present invention provides a high-elastic colloidal material for a pavement transition layer. The matrix material uses highly viscous modified asphalt. The rubber particles are used to absorb the light oil components in the asphalt to achieve an elastic enhancement effect, so that the material has stronger elastic recovery ability and deformation ability. The fibers are added to form a three-dimensional network structure to further increase the toughness and strength of the material and increase the ultimate tensile strength of the material. Through the elastic enhancement of the rubber particles and the toughening and strengthening of the fibers, the high-elastic colloidal material has higher stress resistance and greater deformation coordination.

[0040] The present invention provides a high-elastic colloidal material for a pavement transition layer. By analyzing the microscopic volume change state under the action of asphalt and rubber particles, the volume relationship between the rubber particles and the matrix asphalt acting on them is determined. The fiber adsorbs asphalt to form an asphalt film on its surface, which fills the remaining voids after the rubber particles expand. By establishing a volume model relationship, the mixing ratios of the fiber, rubber particles, and asphalt are determined to give full play to the functions of various materials, ensuring that the high-elastic colloidal material has good performance, and adjusting the raw material ratios through volume parameter control to make the elastic, tough, and strength properties of the high-elastic colloidal material controllable.

[0041] The present invention provides a high-elastic colloidal material for a pavement transition layer. When directly scraped and coated on the road surface, it can play a role in crack resistance and waterproofing. Using rubber powder as the raw material of the high-elastic colloidal material, industrial waste is recycled, realizing the recycling of waste resources, resource conservation, and high efficiency and environmental protection. Specific embodiments

[0042] In order to make the technical means, creative features, achieved purposes and functions of the present invention easy to understand, the present invention will be further described below in conjunction with specific embodiments. However, the following embodiments are only the preferred embodiments of the present invention, not all of them. Based on the embodiments in the implementation manners, other embodiments obtained by those skilled in the art without creative efforts all fall within the protection scope of the present invention.

[0043] A highly elastic colloidal material for a pavement transition layer, which comprises asphalt, rubber particles and fibers. The densities of the raw materials are detected, and the results are shown in Table 1 below:

[0044] Table 1 Densities of raw materials

[0045] Material Asphalt Fiber Rubber powder <![CDATA[Density (g / cm 3 )]]> 1.06 0.8 1.10

[0046] 1m 3 For the highly elastic colloidal material for the pavement transition layer, the incorporation amounts of the raw materials are determined according to the following method: Asphalt wraps around the surface of the rubber particles to form a certain action area, causing the volume of the rubber particles to expand. The asphalt is heated to 160 - 170 °C, the mesh number of the rubber particles is selected as 40 mesh, the rubber particles and the asphalt are mixed according to a volume ratio of 2:8, sheared with a shear instrument for 2 h, and after standing for 24 h, the sample is taken out. Using the scanning electron microscope image recognition technology, the number of rubber particles in the sample is identified as 23, and the scanning electron microscope image is divided into grids by the grid method, and the area of each grid is 1×1um 2 , and the area of the rubber particles occupying the grid and the circumscribed rectangle area of the rubber particles are statistically shown in Table 2 below:

[0047] Table 2 Rubber particle area and circumscribed rectangle area obtained by scanning electron microscope image recognition technology

[0048]

[0049]

[0050] The area of the rubber particles occupying the grid is statistically calculated, and its volume expansion rate and volume filling rate are determined according to the following formula:

[0051]

[0052]

[0053]

[0054] Example 1:

[0055] Select granular fibers, the diameter of the fibers is 0.25 mm, and the specific surface area of the fibers is 30m 2 / kg, the fiber adsorbs asphalt and forms an asphalt film with a certain thickness on its surface. The thickness of the asphalt film is taken as 20 μm and is filled in the voids after the rubber particles expand. Calculate the volume of asphalt adsorbed by the fiber and the volume of the fiber according to the following formula:

[0056] P g1 =P x ×u×SA×ρ x =4.8P x

[0057] P x +P g1 +P g3 =1 - P f ×(1 + γ)=0.539

[0058] P g3 =(1 - α)×(1 - P f ×(1 + γ))=0.257

[0059] The above calculation gives: P x =0.190, P g1 =0.091, P g3 =0.257. The asphalt mentioned above consists of two parts: asphalt interacting with rubber particles and asphalt adsorbed by fibers. Calculate the asphalt dosage according to the following formula:

[0060] P g2 =P f ×γ = 0.11

[0061] P g =P g1 +P g2 +P g3 =0.458

[0062] The high - elastic colloid material is composed of rubber particles, asphalt, and fibers. Calculate the amounts of rubber particles, asphalt, and fibers incorporated into the high - elastic colloid material according to the following formula:

[0063] m f =P f ×ρ f =386.1 kg

[0064] m x =P x ×ρ x =152.0 kg

[0065] m g =P g ×ρ g =485.5 kg

[0066] Prepare the high-elastic colloid material for the road surface transition layer according to the above ratio and conduct performance tests. The results are shown in Table 3 below:

[0067] Table 3 Performance Test Results of High-Elastic Colloid Material

[0068] Test items Test results Technical requirements Elongation at break, / % 1540 >800 Elastic recovery rate, % 95 ≥85 Tensile strength, MPa 4.3 ≥0.8 Bond strength, MPa 2.1 ≥0.4

[0069] Example 2:

[0070] Select granular fibers with a fiber diameter of 0.2 mm and a specific surface area of 37.5 m 2 / kg. The fibers adsorb asphalt and form an asphalt film with a certain thickness on their surface. The thickness of the asphalt film is taken as 15 μm and filled in the voids after the rubber particles expand. Calculate the asphalt adsorption volume and fiber volume of the fibers according to the following formula:

[0071] P g1 = P x ×u×SA×ρ x = 0.45P x

[0072] P x + P g1 + P g3 = 1 - P f ×(1 + γ)= 0.539

[0073] P g3 =(1 - α)×(1 - P f ×(1 + γ))= 0.257

[0074] The above calculations yield: P x = 0.194, P g1 = 0.089, P g3 = 0.257. The asphalt mentioned above consists of two parts: asphalt interacting with rubber particles and asphalt adsorbed by fibers. Calculate the asphalt dosage according to the following formula:

[0075] P g2 = P f ×γ = 0.11

[0076] P g = P g1 + P g2 + P g3 = 0.456

[0077] The high-elastic colloid material is composed of rubber particles, asphalt, and fibers. Calculate the amounts of rubber particles, asphalt, and fibers incorporated into the high-elastic colloid material according to the following formula:

[0078] m f = P f ×ρf = 386.1 kg

[0079] m x = P x × ρ x = 155.2 kg

[0080] m g = P g × ρ g = 483.4 kg

[0081] Prepare the high-elastic colloid material for the pavement transition layer according to the above ratio and conduct performance tests. The results are shown in Table 4 below:

[0082] Table 4 Performance test results of high-elastic colloid material

[0083] Test items Test results Technical requirements Elongation at break, / % 1610 >800 Elastic recovery rate, % 96.2 ≥85 Tensile strength, MPa 4.0 ≥0.8 Bond strength, MPa 2.7 ≥0.4

[0084] Example 3:

[0085] Select granular fibers with a fiber diameter of 0.4 mm and a specific surface area of 18.75 m 2 / kg. The fibers adsorb asphalt and form an asphalt film with a certain thickness on their surface. The thickness of the asphalt film is taken as 25 um and filled in the voids after the rubber particles expand. Calculate the asphalt adsorption volume and fiber volume according to the following formula:

[0086] P g1 = P x × u × SA × ρ x = 0.375 P x

[0087] P x + P g1 + P g3 = 1 - P f × (1 + γ) = 0.539

[0088] P g3 = (1 - α) × (1 - P f × (1 + γ)) = 0.257

[0089] The above calculations yield: P x = 0.205, P g1 = 0.077, P g3 = 0.257. The asphalt mentioned above consists of two parts: the asphalt that interacts with the rubber particles and the asphalt adsorbed by the fibers. Calculate the asphalt dosage according to the following formula:

[0090] P g2 = P f × γ = 0.11

[0091] Pg = P g1 + P g2 + P g3 = 0.444

[0092] The high-elastic colloidal material described above is composed of rubber particles, asphalt, and fibers. The amounts of rubber particles, asphalt, and fibers incorporated into the high-elastic colloidal material are calculated according to the following formula:

[0093] m f = P f × ρ f = 445.5 kg

[0094] m x = P x × ρ x = 164.0 kg

[0095] m g = P g × ρ g = 470.6 kg

[0096] The high-elastic colloidal material for the road surface transition layer is prepared according to the above ratio, and a performance test is carried out. The results are shown in Table 5 below:

[0097] Table 5 Performance Test Results of High-Elastic Colloidal Material

[0098] Test items Test results Technical requirements Elongation at break, / % 1521 >800 Elastic recovery rate, % 93.2 ≥85 Tensile strength, MPa 4.1 ≥0.8 Bond strength, MPa 3.0 ≥0.4

[0099] The above shows and describes the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited by the above embodiments. The above embodiments and the descriptions in the specification are only preferred examples of the present invention and are not used to limit the present invention. Without departing from the spirit and scope of the present invention, the present invention will have various changes and improvements, and these changes and improvements all fall within the scope of the present invention claimed. The scope of protection claimed by the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for preparing a highly elastic colloid material for a pavement transition layer, characterized in that: The steps include: (1) The high elastic colloid material is composed of rubber particles, asphalt, and fibers. The rubber particles interact with the asphalt to expand the volume of the rubber particles. The volume expansion rate and volume filling rate of the rubber particles are determined by scanning electron microscope image processing technology. The volume filling rate is calculated based on the volume expansion rate. 3 The volume of rubber particles in the high elastic colloid material, and the volume of asphalt interacting with the rubber particles is calculated based on the volume expansion rate; The scanning electron microscope image processing technology is used to heat asphalt to 160-170°C, mix rubber particles and asphalt in a volume ratio of 2:8, use a shearing machine to shear for 2 hours, and after standing for 24 hours, take out the sample, use scanning electron microscope image recognition technology to identify the number of rubber particles in the sample, and use the grid method to divide the scanning electron microscope image into grids, count the area of ​​the grid occupied by the rubber particles and the area of ​​the circumscribed rectangle of the rubber particles, and determine its volume expansion rate and volume filling rate according to the following formula: S i =i×G0 Where: S i ——Scanning electron microscope image to identify the area of ​​a single rubber particle, um 2 ; i——Number of grids occupied by rubber particles in the SEM image; G0——Area of ​​a single grid, um 2 ;γ——Volume expansion rate of rubber particles, %;β——Volume filling rate of rubber particles, %;n——Number of particles identified by scanning electron microscope image;D——Diameter of rubber particles, mm;J i ——Area of ​​the rectangle circumscribing the rubber particles in the SEM image, um 2 ;P f ——1m 3 Volume of rubber particles in highly elastic colloid materials, m 3 ; (2) The fiber surface absorbs asphalt to form an asphalt film of a certain thickness. After the fiber absorbs asphalt, it fills the gaps after the rubber particles expand. The remaining space is filled with asphalt. According to the thickness of the asphalt film and the specific surface area of ​​the fiber, the volume ratio of the fiber to the fiber-absorbed asphalt is determined. Combined with the volume of the gaps filled by the fiber after the fiber absorbs asphalt, the volume of the fiber-absorbed asphalt and the volume of the fiber are calculated. According to the volume of the space after the fiber absorbs asphalt, the volume of the asphalt filling the remaining space is calculated. The fiber adsorbed asphalt volume and fiber volume were calculated according to the following formula: P g1 =P x ×u×SA×ρ x P x +P g1 +P g3 =1-P f ×(1+γ) P g3 =(1-α)×(1-P f ×(1+c)) Where: P g1 ——The volume of asphalt interacting with fibers in the high-elastic colloid material, m 3 ;P x ——Fiber volume in highly elastic colloid material, m 3 ; u——thickness of asphalt film on fiber surface, um; SA——specific surface area of ​​fiber, m 2 / kg; ρ x ——Fiber density, kg / m 3 ; r——diameter of fiber particles, mm; P g3 ——Volume of asphalt filling the final voids, m 3 ; α——the spatial volume filling rate of the sphere formed by the fiber after adsorbing asphalt, which is 52.3%; (3) The asphalt described above includes asphalt that interacts with rubber particles, asphalt that is adsorbed by fibers, and asphalt that fills the final voids. The volume of asphalt in the total high-elastic colloid material is calculated; Calculate the asphalt dosage according to the following formula: P g2 =P f ×γ P g =P g1 +P g2 +P g3 Where: P g ——Volume of asphalt in high elastic colloid material, m 3 ;P g2 ——The volume of asphalt interacting with rubber particles in the high-elastic colloid material, m 3 ; (4) Based on the calculated volumes of rubber particles, asphalt, and fiber, combined with the density of rubber particles, asphalt, and fiber, calculate the mass per cubic meter. 3 The amount of rubber particles, asphalt and fiber added to the high-elastic colloid material; The proportion of raw materials added to the high elastic colloid material is calculated according to the following formula: m f =P f ×ρ f m x =P x ×ρ x m g =P g ×ρ g Where: m f ——1m 3 Amount of rubber particles in colloid material, kg; m x ——1m 3 Fiber dosage in colloid material, kg; m g ——1m 3 Asphalt dosage in colloid material, kg; ρ f ——Density of rubber particles, kg / m 3 ρ g ——Asphalt density, kg / m 3 .

2. A method for preparing a highly elastic colloid material for a road surface transition layer according to claim 1, characterized in that: The fibers in the high-elastic colloid material are granular fibers with a diameter of 0.2-0.4 mm, and the rubber particles have a mesh number of 30-50.

3. The method for preparing a highly elastic colloid material for a road surface transition layer according to claim 1, characterized in that: The asphalt in the high-elastic colloid material is SBS modified asphalt, and the thickness of the asphalt film formed by the fiber adsorbing the asphalt is 15-25um.

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