Hydraulic fiber asphalt concrete with low slope flow value and preparation method thereof

Abstract

The present invention belongs to the technical field of power station building materials, and specifically relates to a hydraulic fiber asphalt concrete with a low slope flow value and a preparation method thereof. The hydraulic fiber asphalt concrete with a low slope flow value in the present invention is composed of the following materials in parts by weight: 34-43 parts of asphalt; 220-260 parts of coarse aggregate; 240-280 parts of fine aggregate; 50-80 parts of filler; 1-4 parts of fiber. The basalt fiber is modified, the materials are prepared according to the ratio, the dry material is prepared, the modified asphalt of the ratio is heated to 160°C-170°C, added to the prepared dry material, and stirred for 3-5 minutes to obtain. The fiber asphalt concrete in the present invention can effectively improve the stability of high-temperature slopes, extend the service life of the anti-seepage layer structure, and improves the low-temperature performance, deformation adaptability, and durability, providing technical support for the safety of hydraulic anti-seepage structures.

Description

Technical Field

[0001] The invention belongs to the technical field of power station building materials, and in particular relates to hydraulic fiber asphalt concrete with a low slope flow value and a preparation method thereof. Background Art

[0002] Asphalt concrete has good impermeability, durability and deformation adaptability, and is often used for anti-seepage of the entire reservoir basin of a pumped storage power station. The asphalt concrete panels at the bottom of the reservoir are laid horizontally, and the asphalt concrete panels at the bank of the reservoir are laid on a slope with a slope of usually 1:1.7. The panels are required to remain stable during the operation of the power station. Asphalt concrete is a non-homogeneous viscoelastic material composed of aggregate, asphalt, filler, etc. Its performance is greatly affected by temperature, and the amount of asphalt in the anti-seepage layer asphalt concrete is relatively large, and the oil-stone ratio is usually 7.0%-8.0%. In actual projects, the daytime is long in the northwest region in summer, and the asphalt concrete panels are exposed to direct sunlight, and the surface temperature can reach 70°C. Affected by its own material properties and the external ambient temperature, asphalt concrete is prone to move along the slope, resulting in failure of the anti-seepage layer structure, affecting the safe and stable operation of the power station.

[0003] Fiber asphalt concrete is composed of coarse aggregate, fine aggregate, filler, asphalt and fiber. After the fiber, filler and asphalt are mixed, the three are intertwined, and the fiber absorbs asphalt, which can increase the viscosity of asphalt mortar and improve the high-temperature slope flow performance of asphalt concrete. However, conventional basalt fiber has less surface active substances and weak adsorption effect with modified asphalt, so the effect of improving the high-temperature performance of fiber asphalt concrete is not ideal. Therefore, it is urgent to propose a hydraulic fiber asphalt concrete with a low slope flow value and a preparation method thereof. Summary of the invention

[0004] The present invention provides a hydraulic fiber asphalt concrete with a low slope flow value and a preparation method thereof. One of its purposes is to provide a hydraulic fiber asphalt concrete that can effectively improve the stability of high-temperature slopes and extend the service life of anti-seepage layer structures; the second purpose is to provide a hydraulic asphalt concrete that can improve low-temperature performance, deformation adaptability, and durability, thereby providing technical support for the safety of hydraulic anti-seepage structures; the third purpose is to provide a low-cost, high-performance, high-cleanliness green and environmentally friendly hydraulic fiber asphalt concrete.

[0005] To achieve the above object, the technical solution adopted by the present invention is:

[0006] A hydraulic fiber asphalt concrete with a low slope flow value is suitable for the anti-seepage layer structure of the reservoir bank of a pumped storage power station, and has a low slope flow value under high temperature; in parts by weight, the concrete comprises 34-43 parts of modified asphalt; 220-260 parts of coarse aggregate; 240-280 parts of fine aggregate; 50-80 parts of filler; and 1-4 parts of fiber; the fiber is modified basalt fiber.

[0007] The fiber has a length of 6-9 mm, a diameter of 10-15 μm, a tensile strength of 1500-3200 MPa, and an elastic modulus of 80-120 GPa.

[0008] The asphalt is SBSI-C modified asphalt, with a needle penetration of 7.1 mm, a softening point of 56° C., and an elongation of 62 cm at 5° C.

[0009] The coarse aggregate and the fine aggregate are both limestone.

[0010] The filler is limestone powder.

[0011] The particle size of the coarse aggregate is 2.36-16 mm; the particle size of the fine aggregate is 0.075-2.36 mm.

[0012] A method for preparing hydraulic fiber asphalt concrete with low slope flow value comprises the following steps:

[0013] Step 1: modifying basalt fiber;

[0014] Step 2: Prepare materials according to the ratio;

[0015] Step 3, preparing dry material;

[0016] Heat the proportion of coarse aggregate, fine aggregate and filler to 165℃-175℃, stir evenly, add modified fiber and continue stirring for a total of 2-3 minutes to obtain a uniformly mixed dry material;

[0017] Step 4: Heat the proportion of asphalt to 160°C-170°C, add it to the dry material prepared in step 3, and stir for 3-5 minutes to obtain fiber asphalt concrete.

[0018] In the step 1, the basalt fiber is modified by using a silane coupling agent.

[0019] The specific modification method is to prepare a silane coupling agent solution according to the mass ratio of water: anhydrous ethanol: silane coupling agent 20-30: 70-80: 2-5, immerse the basalt fiber in the silane coupling agent solution, and dry it after immersing for a preset time to obtain modified fiber.

[0020] The preset soaking time is 20-60 minutes.

[0021] Beneficial effects: (1) The present invention adds modified basalt modified fiber to asphalt concrete to obtain fiber asphalt concrete, which can effectively improve the stability of high-temperature slopes and extend the service life of the anti-seepage layer structure.

[0022] (2) The modified basalt fiber in the present invention improves the low temperature performance, deformation adaptability and durability of hydraulic asphalt concrete, providing technical support for the safety of hydraulic anti-seepage structures.

[0023] The above description is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention, the preferred embodiments of the present invention are described in detail below. DETAILED DESCRIPTION

[0024] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0025] Embodiment 1: A hydraulic fiber asphalt concrete with a low slope flow value, which is suitable for the anti-seepage layer structure of the reservoir bank of a pumped storage power station, and has a low slope flow value at high temperature; in parts by weight, 34-43 parts of modified asphalt; 220-260 parts of coarse aggregate; 240-280 parts of fine aggregate; 50-80 parts of filler; 1-4 parts of fiber; the fiber is modified basalt fiber.

[0026] Furthermore, the fiber has a length of 6-9 mm, a diameter of 10-15 μm, a tensile strength of 1500-3200 MPa, and an elastic modulus of 80-120 GPa.

[0027] Furthermore, the asphalt is SBSI-C modified asphalt, with a needle penetration of 7.1 mm, a softening point of 56°C, and an elongation of 62 cm at 5°C.

[0028] Furthermore, the coarse aggregate and the fine aggregate are both made of limestone.

[0029] Furthermore, the filler is limestone powder.

[0030] Furthermore, the particle size of the coarse aggregate is 2.36-16 mm; the particle size of the fine aggregate is 0.075-2.36 mm.

[0031] In actual use, the basalt fiber is surface-modified by a silane coupling agent. On the one hand, the roughness of the fiber surface is improved, which increases the mechanical bonding between the fiber and asphalt. On the other hand, the silane coupling agent reacts with the Si-OH bonds on the surface of the basalt fiber to generate a large number of Si-O polar bonds, which increases the surface activity of the fiber and helps to improve the adhesion between the fiber and asphalt, without adversely affecting the single-filament tensile properties of the fiber.

[0032] The fiber asphalt concrete of the invention consists of coarse aggregate, fine aggregate, filler, modified asphalt and modified fiber, and effectively improves the high-temperature slope stability and durability of the anti-seepage layer asphalt concrete.

[0033] The length, diameter, tensile strength and elastic modulus of the fiber in this embodiment are set so that the modified basalt fiber can enhance the interfacial bonding between the fiber and asphalt while still maintaining good tensile properties.

[0034] The modified asphalt using the above technical solution makes its high and low temperature performance better than the base asphalt, which is beneficial to the slope flow performance of asphalt concrete.

[0035] Both coarse aggregate and fine aggregate are made of limestone, which is an alkaline aggregate and is beneficial to the adhesion between aggregate and asphalt.

[0036] The technical solution of using limestone mineral powder as filler can improve the compactness of asphalt concrete, thereby improving the strength and stability of asphalt concrete.

[0037] The indicators of coarse aggregate, fine aggregate and limestone powder in this embodiment all meet the technical requirements for asphalt concrete coarse aggregate, fine aggregate and filler specified in the "Design Specification for Asphalt Concrete Slabs and Core Walls of Earth-Rock Dams" NB / T 11015-2022.

[0038] Embodiment 2: A method for preparing hydraulic fiber asphalt concrete with low slope flow value, comprising the following steps:

[0039] Step 1: modifying basalt fiber;

[0040] Step 2: Prepare materials according to the ratio;

[0041] Step 3, preparing dry material;

[0042] Heat the proportion of coarse aggregate, fine aggregate and filler to 165℃-175℃, stir evenly, add modified fiber and continue stirring for a total of 2-3 minutes to obtain a uniformly mixed dry material;

[0043] Step 4: Heat the proportion of asphalt to 160°C-170°C, add it to the dry material prepared in step 3, and stir for 3-5 minutes to obtain fiber asphalt concrete.

[0044] Furthermore, in the step 1, the basalt fiber is modified by using a silane coupling agent.

[0045] Furthermore, the specific method of modification is to prepare a silane coupling agent solution according to the mass ratio of water: anhydrous ethanol: silane coupling agent of 20-30: 70-80: 2-5, soak the basalt fiber in the silane coupling agent solution, and dry it after soaking for a preset time to obtain modified fiber.

[0046] Furthermore, the preset soaking time is 20-60 minutes.

[0047] The prepared fiber asphalt concrete was molded by the Marshall compaction method to produce asphalt concrete specimens with a diameter of Φ101.6 mm and a height of 63.5 mm±1.2 mm.

[0048] By adopting the above technical scheme, the slope flow test of asphalt concrete was carried out according to the "Test Procedure for Hydraulic Asphalt Concrete" DL / T5362-2018. The test temperature was 70°C, and after 48 hours, the slope flow value was detected to be 0.15mm, which met the relevant requirements of the "Design Code for Asphalt Concrete Slabs and Core Walls of Earth-Rock Dams" NB / T 11015-2022 (<0.8mm). Therefore, the fiber asphalt concrete prepared by this method has good slope stability.

[0049] Comparative test:

[0050] Example 3: Prepare 35 parts of SBS modified asphalt, 255 parts of coarse aggregate, 245 parts of fine aggregate, and 60 parts of filler.

[0051] Heat the prepared coarse aggregate, fine aggregate and filler to 170°C, stir evenly, add the proportion of modified fiber and continue stirring for a total of 3 minutes to obtain a uniformly mixed dry material; heat the modified asphalt to 165°C, add it to the prepared dry material, stir for 3-5 minutes, and obtain fiber asphalt concrete.

[0052] Example 4: Prepare 35 parts of SBS modified asphalt, 255 parts of coarse aggregate, 245 parts of fine aggregate, 60 parts of filler, and 2.5 parts of unmodified fiber.

[0053] Heat the prepared coarse aggregate, fine aggregate and filler to 165°C, stir evenly, add unmodified fiber and continue stirring for a total of 2 minutes to obtain a uniformly mixed dry material; heat the modified asphalt to 160°C, add it to the prepared dry material, stir for 4 minutes, and obtain fiber asphalt concrete.

[0054] Example 5: Prepare 37 parts of SBS modified asphalt, 230 parts of coarse aggregate, 270 parts of fine aggregate, 70 parts of filler, and 1.5 parts of modified fiber.

[0055] Heat the prepared coarse aggregate, fine aggregate and filler to 175°C, stir evenly, add the modified fiber and continue stirring for a total of 2 minutes to obtain a uniformly mixed dry material; heat the modified asphalt to 170°C, add it to the prepared dry material, stir for 5 minutes, and obtain fiber asphalt concrete.

[0056] Example 6: Prepare 37 parts of SBS modified asphalt, 230 parts of coarse aggregate, 270 parts of fine aggregate, 70 parts of filler, and 2.5 parts of modified fiber.

[0057] Heat the prepared coarse aggregate, fine aggregate and filler to 168°C, stir evenly, add modified fiber and continue stirring for a total of 2 minutes to obtain a uniformly mixed dry material; heat the proportion of modified asphalt to 168°C, add it to the prepared dry material, stir for 4 minutes, and obtain fiber asphalt concrete.

[0058] Example 7: Prepare 37 parts of SBS modified asphalt, 230 parts of coarse aggregate, 270 parts of fine aggregate, 70 parts of filler, and 3.5 parts of modified fiber.

[0059] Heat the prepared coarse aggregate, fine aggregate and filler to 175°C, stir evenly, add the modified fiber and continue stirring for a total of 2 minutes to obtain a uniformly mixed dry material; then heat the modified asphalt to 160°C, add it to the prepared dry material, stir for 5 minutes, and obtain fiber asphalt concrete.

[0060] Example 8: Prepare 35 parts of SBS modified asphalt, 255 parts of coarse aggregate, 245 parts of fine aggregate, 60 parts of filler, and 1.5 parts of modified fiber.

[0061] Heat the prepared coarse aggregate, fine aggregate and filler to 175°C, stir evenly, add the modified fiber and continue stirring for a total of 4 minutes to obtain a uniformly mixed dry material; then heat the modified asphalt to 165°C, add it to the prepared dry material, stir for 4 minutes, and obtain fiber asphalt concrete.

[0062] Example 9: Prepare 35 parts of SBS modified asphalt, 255 parts of coarse aggregate, 245 parts of fine aggregate, 60 parts of filler, and 3.5 parts of modified fiber.

[0063] Heat the prepared coarse aggregate, fine aggregate and filler to 165°C, stir evenly, add the modified fiber and continue stirring for a total of 3 minutes to obtain a uniformly mixed dry material; then heat the modified asphalt to 160°C, add it to the prepared dry material, stir for 3 minutes, and obtain fiber asphalt concrete.

[0064] Example 10: Prepare 35 parts of SBS modified asphalt, 265 parts of coarse aggregate, 235 parts of fine aggregate, 60 parts of filler, and 2.5 parts of modified fiber.

[0065] Heat the prepared coarse aggregate, fine aggregate and filler to 170°C, stir evenly, add the modified fiber and continue stirring for a total of 3 minutes to obtain a uniformly mixed dry material; then heat the modified asphalt to 165°C, add it to the prepared dry material, stir for 3 minutes, and obtain fiber asphalt concrete.

[0066] Example 11: Prepare 35 parts of SBS modified asphalt, 230 parts of coarse aggregate, 270 parts of fine aggregate, 60 parts of filler, and 2.5 parts of modified fiber.

[0067] Heat the prepared coarse aggregate, fine aggregate and filler to 165°C, stir evenly, add the modified fiber and continue stirring for a total of 4 minutes to obtain a uniformly mixed dry material; then heat the modified asphalt to 165°C, add it to the prepared dry material, stir for 2 minutes, and obtain fiber asphalt concrete.

[0068] According to the "Test Procedure for Hydraulic Asphalt Concrete" DL / T5362-2018, the slope flow test was carried out on asphalt concrete. The test temperature was 70°C, and the slope flow value was tested after 48 hours. The test results are shown in Table 1.

[0069] Table 1 Experimental results of Example 3 to Example 11

[0070] Test items Embodiment 3 Embodiment 4 Embodiment 5 Embodiment 6 Embodiment 7 Embodiment 8 Embodiment 9 Embodiment 10 Embodiment 11 Slope flow value (mm) 2.69 0.94 0.75 0.55 0.52 0.37 0.16 0.20 0.56

[0071] It can be seen from the above table that Example 4 is an asphalt concrete prepared with unmodified fibers, and its slope flow value is 0.94 mm, which does not meet the relevant requirements of the "Design Specification for Asphalt Concrete Panels and Core Walls of Earth-Rock Dams" NB / T 11015-2022 (<0.8 mm). The slope flow values ​​of the asphalt concrete with modified fibers added are all less than 0.8 mm. Therefore, modified fibers can reduce the slope flow value of asphalt concrete and improve its stability under high temperature conditions.

[0072] In the absence of conflicts, technicians in this field can combine the relevant technical features in the above examples according to actual conditions to achieve corresponding technical effects. The specific combinations are not described here one by one.

[0073] In the present invention, the descriptions of "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" or "second" may explicitly or implicitly include at least one of the features.

[0074] The above are only preferred embodiments of the present invention. The present invention will not be limited to the embodiments shown herein, but should conform to the widest scope consistent with the principles and novel features disclosed herein. Any simple modification, equivalent changes and modifications made to the above embodiments according to the technical essence of the present invention still fall within the scope of the technical solution of the present invention.

Claims

1. A hydraulic fiber asphalt concrete with a low slope flow value, characterized in that: Applicable to the anti-seepage layer structure of the reservoir bank of pumped storage power stations, with low slope flow value under high temperature; 34-43 parts by weight of asphalt; 220-260 parts of coarse aggregate; 240-280 parts of fine aggregate; 50-80 parts of filler; 1-4 parts of fiber; the fiber is modified basalt fiber, the Si-OH bond on the surface of the basalt fiber reacts to generate a large number of Si-O polar bonds, the modified basalt fiber improves the surface roughness of the fiber, increases the mechanical bonding force between the fiber and asphalt, improves the surface activity of the fiber, helps to improve the adhesion between the fiber and asphalt, and has no adverse effect on the single fiber tensile properties of the fiber; The filler is limestone powder; The particle size of the coarse aggregate is 2.36-16 mm; the particle size of the fine aggregate is 0.075-2.36 mm; The fiber has a length of 6-9 mm, a diameter of 10-15 μm, a tensile strength of 1500-3200 MPa, and an elastic modulus of 80-120 GPa, so that the modified basalt fiber can enhance the interfacial bonding between the fiber and asphalt while still maintaining good tensile properties; The asphalt is SBSI-C modified asphalt, with a needle penetration of 7.1 mm, a softening point of 56°C, and an elongation of 62 cm at 5°C; The modified basalt fiber is modified by using a silane coupling agent. The specific modification method is to prepare a silane coupling agent solution according to a mass ratio of water: anhydrous ethanol: silane coupling agent of 20-30: 70-80: 2-5, immerse the basalt fiber in the silane coupling agent solution, and dry the basalt fiber after immersion for a preset time to obtain the modified fiber.

2. The hydraulic fiber asphalt concrete with low slope flow value as claimed in claim 1, characterized in that: The coarse aggregate and the fine aggregate are both limestone.

3. The method for preparing a hydraulic fiber asphalt concrete with a low slope flow value as claimed in claim 1 or 2, characterized in that: The following steps are included: Step 1: modifying basalt fiber; Step 2: Prepare materials according to the ratio; Step 3, preparing dry material; Heat the proportion of coarse aggregate, fine aggregate and filler to 165℃-175℃, stir evenly, add modified fiber and continue stirring for a total of 2-3 minutes to obtain a uniformly mixed dry material; Step 4: Heat the proportion of asphalt to 160°C-170°C, add it to the dry material prepared in step 3, and stir for 3-5 minutes to obtain fiber asphalt concrete; In the step 1, the basalt fiber is modified by using a silane coupling agent; The specific modification method is to prepare a silane coupling agent solution according to the mass ratio of water: anhydrous ethanol: silane coupling agent of 20-30: 70-80: 2-5, soak the basalt fiber in the silane coupling agent solution, and dry it after soaking for a preset time to obtain modified fiber.

4. The method for preparing a hydraulic fiber asphalt concrete with a low slope flow value as claimed in claim 3, characterized in that: The preset soaking time is 20-60 minutes.