A method of preparing an anti-aging asphalt concrete panel

Abstract

This invention discloses a method for preparing an anti-aging asphalt concrete panel, relating to the field of asphalt concrete material preparation technology. The panel has a total thickness of 20cm and adopts a three-layer structure, consisting of a bottom layer, a middle layer, and a top layer from bottom to top. The total thickness of the bottom and middle layers is 16cm, with the bottom layer being 7-9cm thick, the middle layer 9-7cm thick, and the top layer fixed at 4cm. This invention features a layered functional design adapted to dam conditions. The bottom / middle layers emphasize lightweighting, water pressure resistance, and structural support, while the top layer emphasizes anti-aging, high density, impermeability, and erosion resistance. It specifically resists the triple damage of ultraviolet radiation, water, and water pressure to the dam, breaking through the limitations of traditional single-layer dam panels with limited functionality. It balances lightweighting and strength. The bottom / middle layers use honeycomb-shaped lightweight aggregate with a porosity of 40%-60%, resulting in a weight reduction of ≥30% and reducing the pressure on the dam foundation. The top layer uses fine-grained load-bearing aggregate with a density ≥96% and compressive strength ≥35MPa, balancing water pressure and erosion resistance.

Description

Technical Field

[0001] This invention relates to the field of asphalt concrete material preparation technology, specifically to a method for preparing an anti-aging asphalt concrete panel. Background Technology

[0002] Asphalt concrete panels are a core component of the seepage prevention system for hydraulic dams due to their excellent impermeability, ductility, and ease of construction. However, dam panels are subjected to special conditions for a long time: on the one hand, they are exposed to sunlight, and the continuous exposure to ultraviolet rays in the 280-400nm wavelength band causes asphalt oxidation and cracking, leading to embrittlement and cracking of the panels; on the other hand, they are subjected to water immersion, water pressure, and water flow erosion for a long time, which makes the cracks easy to expand and cause leakage. This not only reduces the seepage prevention performance of the dam, but also erodes the foundation structure of the dam, seriously affecting the operational safety and service life of the dam, and significantly increasing the cost of later maintenance and reinforcement.

[0003] Existing technologies for optimizing the anti-aging and seepage prevention of asphalt concrete panels for dams have significant limitations: First, traditional modified asphalt (with added UV absorbers and antioxidants) tends to disperse unevenly during thick-layer pouring of dam panels, and may precipitate out after long-term immersion in water, leading to rapid decline in anti-aging and seepage prevention effects, making it unsuitable for the long-term service requirements of dams; second, to improve water pressure resistance, traditional panels often use high-density aggregates, with a self-weight generally reaching 28-32 kN / m³. 3 This increases the load-bearing pressure on the dam body, making it particularly unsuitable for weak areas such as dam shoulders and slopes. In addition, most existing dam panels are single-layer structures, which cannot specifically resist the dual damage of ultraviolet rays (surface layer) and water pressure and erosion (overall), further shortening the service life.

[0004] Therefore, there is an urgent need for a method for preparing asphalt concrete panels that is suitable for dam conditions. Through structural optimization and process innovation, a synergistic unity of lightweight and high anti-aging performance can be achieved, fundamentally solving the pain points of existing dam panels such as easy aging, and ensuring the long-term safe operation of dams. Summary of the Invention

[0005] To solve the above-mentioned technical problems, the present invention uses a layered structure design, combined with special aggregates and auxiliary heating processes, to enable the panel to not only be lightweight, but also to efficiently absorb ultraviolet rays and improve the surface density, thereby significantly extending the service life of the panel.

[0006] The technical solution adopted in this invention is: a method for preparing an anti-aging asphalt concrete panel. The panel has a total thickness of 20cm and adopts a three-layer structure, consisting of a bottom layer, a middle layer, and a top layer from bottom to top. The total thickness of the bottom and middle layers is 16cm, with the bottom layer being 7-9cm thick, the middle layer being 9-7cm thick, and the top layer being fixed at 4cm. The core of the preparation involves the production of ultraviolet absorbing materials, the production of asphalt concrete aggregates, and the fabrication of the panel structure and mold casting. The specific steps are as follows:

[0007] Step 1: Using honeycomb lightweight aggregate as a carrier, fill it with ultraviolet absorbing material and cure it to prepare water-resistant ultraviolet absorbing aggregate, so that it has water resistance and high-efficiency ultraviolet absorption function.

[0008] Step 2: Prepare lightweight asphalt concrete aggregate for the bottom / middle layer and ultraviolet-absorbing asphalt concrete aggregate for the surface layer separately, control the proportion of each component and the mixing process, and ensure that the properties of each layer of materials are compatible.

[0009] Step 3: Create a layered temperature-controlled mold with heating wires, and pour the bottom / middle layer and surface layer of aggregate mixture in sequence. After vibration, rolling and precise temperature control heating and curing, the layered structure is tightly bonded.

[0010] Step 4: After demolding, cure in a constant temperature and humidity environment, followed by long-term water immersion pretreatment to obtain lightweight, structurally stable finished anti-aging asphalt concrete panels.

[0011] Preferably, the composition of the bottom / middle layer lightweight asphalt concrete aggregate, by mass percentage, includes: 10%-12% asphalt, 60%-65% honeycomb lightweight aggregate, 20%-25% mineral powder, 0.3%-0.5% admixture, and 3%-5% water;

[0012] The same honeycomb lightweight aggregate as the bottom / middle layer is selected as the carrier. The honeycomb lightweight aggregate is selected from at least one of ceramsite, expanded perlite, or foamed concrete aggregate, with ceramsite or water-resistant expanded perlite preferred. Inferior aggregates are prohibited to avoid aggregate disintegration and detachment of absorbent material after long-term soaking. The particle size is 5-15mm (5-10mm fine aggregate is used for the surface layer to improve density, and 10-15mm coarse aggregate is used for the bottom layer to enhance structural support). The porosity is 40%-60% to meet the lightweight requirements of the dam. Before selection, it is dried at 105℃ for 24 hours and has a compressive strength of not less than 3MPa.

[0013] Preferably, the raw materials are prepared as follows: the ultraviolet absorbing material is a composite material composed of one or more of nano-titanium dioxide, ultraviolet absorber UV-327 or UV-360 in a predetermined mass ratio, wherein the nano-titanium dioxide has a particle size of 20-50 nm and a purity of ≥99%; the ultraviolet absorbing material is filled to 60%-80% of the pore volume of the carrier aggregate, and after filling, it is fixed by low temperature drying at 60-80℃ for 1-2 hours, and verified by water immersion for 48 hours to ensure no material precipitation;

[0014] The specifications for UV-327 material are as follows: powder, purity ≥98%, ash content ≤0.1%, melting point 150-155℃, does not decompose below 200℃, and should be used after screening through a 100-mesh sieve; the optimal filling ratio is 65%. Taking 100kg of carrier (porosity 50%) as an example, the filling amount is 65% of the pore volume, and the application amount is approximately 27.1L (approximately 19.0kg) with a 65% filling amount.

[0015] The binary compound system uses nano-titanium dioxide (30nm) + UV-327. Material specifications: nano-titanium dioxide (anatase type, purity ≥99%), UV-327 (purity ≥98%, 100-mesh sieve); ratio and dosage: mass ratio 1.5:1, total filling amount is 70% of the carrier pore volume; taking 100kg carrier (porosity 50%) as an example, the total dosage is about 29.2L (mass about 23.4kg), of which nano-titanium dioxide is about 14.0kg and UV-327 is about 9.4kg;

[0016] The ternary compound system uses nano-titanium dioxide (30nm) + UV-327 + UV-360. The material specifications are: nano-titanium dioxide (anatase type, purity ≥99%), UV-327 (purity ≥98%), and UV-360 (purity ≥98%). The ratio and dosage are: mass ratio 2:1:1, and the total filling amount is 72% of the carrier pore volume. Taking 100kg of carrier (porosity 50%) as an example, the 72% filling amount is optimal, and the total amount is about 30.0L (mass about 24.0kg), of which nano-titanium dioxide is about 12.0kg, UV-327 is about 6.0kg, and UV-360 is about 6.0kg.

[0017] Preferably, the composition of the surface ultraviolet-absorbing asphalt concrete aggregate is consistent with the proportion of the bottom / middle layer lightweight asphalt concrete aggregate. The honeycomb lightweight aggregate in the bottom / middle layer lightweight asphalt concrete aggregate is replaced with an equal mass proportion of water-resistant ultraviolet-absorbing aggregate, and the amounts of asphalt, mineral powder and admixtures are adjusted accordingly to maintain a consistent total proportion.

[0018] Preferred method for preparing each system: The steps are as follows: In the unicomponent compound system: UV-327 is passed through a 100-mesh sieve (sieve residue ≤1%), and placed in a desiccator to prevent moisture absorption; the water-to-material ratio is adjusted according to the difference, with the UV-327 ratio being 1:3, and stirred until there are no particles or lumps, and it is qualified when poured out as a continuous filament; the pretreated carrier is immersed in the paste material, and the soaking time is adjusted according to the filling amount. Stir at low speed for 1 minute every 20 minutes at 20-25℃ to prevent sedimentation. The UV-327 is dried at 70℃ for 1.5 hours, turned over once every 30 minutes, cooled to room temperature and then sealed for storage (≤72 hours), and soaked in clean water at 25±1℃ for 48 hours;

[0019] For the binary compound system: the steps are as follows: dry nano-titanium dioxide at 80℃ for 1 hour (stirring every 15 minutes), add 0.5% polycarboxylate dispersant and dry mix for 2 minutes to prevent agglomeration; pass UV-327 through a 100-mesh sieve (residue ≤1%), place in a desiccator to prevent moisture absorption, and ensure uniform compounding. Dry mix for 3 minutes (200 r / min) according to the corresponding mass ratio (titanium dioxide + UV-327 = 1.5:1), then adjust the paste according to the water-to-material ratio, stir for 6 minutes, and let stand for 10 minutes. If there is no stratification, it is qualified; soak for 1-1.5 hours (total filling amount 65%-75%); after taking it out, gently blow the pores with compressed air to remove dispersant residue, dry at 70℃ with forced ventilation (wind speed 0.5 m / s) for 1.5 hours, control the cooling rate to avoid material peeling, and soak for 48 hours;

[0020] For the ternary compound system: the steps are as follows: nano titanium dioxide is treated according to the single system standard; UV-327 and UV-360 are sieved and then dried at 60℃ for 30 min; the carrier is ceramsite with a porosity of 45%-55%, and the surface is wiped with anhydrous ethanol to improve the adsorption force; paste preparation: weigh the materials at a mass ratio of 2:1:1, first mix the titanium dioxide and dispersant, then add the UV series and dry mix for 4 min, stir at a water-to-material ratio of 1:3.5 at 30℃ for 8 min, and let stand for 15 min until there are no bubbles and the layers separate; after soaking for 1 h, put the aggregate and paste together into a vacuum box, take them out and filter to remove the surface floating material; use a stepped heating mode to detect the absorption rate in the middle to ensure that the material does not decompose, and soak for 72 h.

[0021] Preferably, the asphalt is 70# or 90# petroleum asphalt, whose performance conforms to the national standard GB / T 15180-2010. During the preparation process, it is heated to a molten state at 150-160℃ and mixed with other components at a stirring speed of 30-50r / min at 150-155℃ for 3-4 minutes. The admixture is a lignin sulfonate water-reducing agent with a purity of not less than 95%, which is prepared into a 10% solution before use.

[0022] Preferably, the materials selected for the layered temperature control mold and auxiliary structure are: Q235 steel plate (thickness ≥ 5mm, used for mold body welding, adapted to the anti-deformation requirements of on-site dam prefabrication, with slots); detachable steel partition plate (thickness 3mm, detachable, with silicone sealing strips added to the edges, bolted, and partition plate adjusters installed on the edges); silicone sealing strips (sealing the edges of the partition plate to prevent leakage during casting); high-temperature resistant ceramic clips (fixing the heating wires to prevent adhesion to the mixture and water corrosion); and metal heating wires (stainless steel wire / nickel-chromium alloy wire, temperature resistance ≥ 200℃, arrangement density 5-8 wires / m). 2The layered temperature control mold is pre-embedded at the bottom of the surface casting chamber and connected to a temperature controller with a temperature control accuracy of ±2℃, which can achieve precise temperature control of 140-150℃. The inner wall flatness error of the layered temperature control mold does not exceed 1mm / m, the finished panel has a size deviation of ≤±5mm, a surface flatness error of ≤2mm / m, and no cracks, missing corners, or pitting defects.

[0023] Preferably, when pouring in layers, the pouring speed for the bottom and middle layers is 0.5-1m. 3 The surface layer should be poured at a rate of 0.5-0.7 m / h, using a Φ50mm immersion vibrator at 20-30cm intervals for 30-60 seconds; the surface layer pouring speed should be 0.5-0.7 m / h. 3 / h, after being vibrated on a plate, it is rolled 2-3 times with a pressure of 2-3MPa, and then heated and cured at 140-150℃ for 30-40min.

[0024] Preferably, after demolding, the panel is placed in an environment with a temperature of 20±2℃ and a relative humidity of 60%-70% for 7 days of curing, and is allowed to cool naturally for no less than 24 hours before curing. During the curing period, the ambient temperature is maintained at 15-25℃. After curing, the panel is soaked for 72 hours for water resistance pretreatment.

[0025] Preferably, the intermediate and base materials are pretreated as follows: lightweight aggregate is dried at 105℃ for 24 hours (turned over every 6 hours) and cooled to the corresponding temperature; mineral powder is dried at 80℃ for 1 hour and then stored in a desiccator for moisture protection; asphalt is heated in stages to 150-160℃ to melt and stirred at a constant temperature of 20r / min to prevent aging; water-reducing agent is diluted to a concentration of 10% and stirred evenly without sediment before use; the dried aggregate and mineral powder are put into a forced mixing pot and dry-mixed at 30r / min for 2 minutes to ensure uniform mixing and that the mineral powder adheres to the surface of the aggregate without piling up. Accumulation; Wet mixing and blending: Slowly inject molten asphalt, add diluted water-reducing agent, wet mix at 40 r / min for 1-2 min; after wet mixing for 1 min, spray clean water along the pot wall, adjust the temperature to 150-155℃ and continue stirring for 2 min to ensure that the asphalt evenly coats the aggregate and there is no segregation; Temperature and workability control: The aggregate temperature after wet mixing should be maintained at 145-155℃; Use a slump tester to test the workability and control it at 50-70mm; Take 3 1kg samples to measure the apparent density, discharge the material by belt conveyor, and complete the pouring within 30 min.

[0026] Preferably, the material composition and proportion of the surface aggregate are as follows: the mass ratio of asphalt, mineral powder, water-reducing agent, and water is exactly the same as that of the base / intermediate layers. The honeycomb lightweight aggregate is replaced with water-resistant, load-bearing, UV-absorbing aggregate, with the dosage adjusted synchronously according to a 60%-65% mass ratio. Adaptation adjustments: 5-10mm fine-particle-size load-bearing aggregate is used for the surface layer to improve its density. For load-bearing aggregates using a ternary compound system, the asphalt dosage needs to be increased by 0.5%-1%. The overall production process is consistent with that of the base / intermediate layer aggregates, except that the load-bearing aggregates do not require secondary drying and are directly added to the mixing pot. Inspection is required before addition. The moisture content of the aggregate should be controlled between 10% and 15%. If the moisture content is too high, reduce the amount of clean water; if it is too low, add water as needed. The mixing temperature should be strictly controlled between 145 and 150°C, and the mixing time should be shortened to 2.5-3 minutes, including 1 minute of dry mixing and 1.5-2 minutes of wet mixing, to reduce the collision between the aggregate and the mixing paddle. During wet mixing, the asphalt injection speed should be slowed down and injected evenly along the inner wall of the mixing pot. The water-reducing agent should be mixed with clean water and added together to improve workability and reduce material agglomeration. The surface aggregate should be poured within 20 minutes, which is 10 minutes shorter than the bottom / middle layer to avoid insufficient bonding strength.

[0027] Preferably, the prepared panel is adapted to dam conditions, and the physical performance indicators of the panel include: weight reduction ratio ≥30%, surface density ≥96%, compressive strength ≥35MPa, ultraviolet absorption rate ≥85%, and after being subjected to the combined effects of 1000h ultraviolet aging and 720h water immersion, the compressive strength loss rate does not exceed 10%.

[0028] This invention provides a method for preparing anti-aging asphalt concrete panels. It has the following beneficial effects:

[0029] (I) The preparation method of this anti-aging asphalt concrete panel is designed with layered functionalization to adapt to dam conditions. The bottom / middle layer focuses on lightweight, water pressure resistance and structural support, while the surface layer focuses on anti-aging, high density and impermeability and erosion resistance. It specifically resists the triple damage of ultraviolet rays + water body + water pressure to the dam, breaking through the limitation of the single function of traditional single-layer dam panels.

[0030] (II) The preparation method of this anti-aging asphalt concrete panel adopts the design of "carrier loading + multi-system compounding" to solve the problem of easy dispersion and precipitation of traditional materials. The ultraviolet absorption rate is the highest in the whole band, with 91%-93%. After 1000h ultraviolet aging + 720h water immersion, the compressive strength loss rate is ≤7%, and the service life is more than 2.5 times that of traditional asphalt concrete panels. It is suitable for dams exposed to direct sunlight and long-term immersion conditions.

[0031] (III) The preparation method of this anti-aging asphalt concrete panel takes into account both lightweight and strength. The bottom / middle layer uses honeycomb lightweight aggregate with a porosity of 40%-60%, and the finished product weight is reduced by ≥30%, which reduces the pressure on the dam foundation. The surface layer uses fine-grained load-bearing aggregate with a density of ≥96% and a compressive strength of ≥35MPa, which takes into account the resistance to water pressure and erosion.

[0032] (iv) The preparation method of the anti-aging asphalt concrete panel uses lightweight water-resistant aggregate as a carrier, compounded with ultraviolet absorbing material and pretreated with water resistance. This method not only ensures lightweighting to reduce the load on the dam body, but also achieves efficient ultraviolet blocking, while avoiding the material from leaching into the water, making it suitable for long-term immersion conditions of the dam.

[0033] (V) The preparation method of the anti-aging asphalt concrete panel adopts a precise surface heating and curing process, which is suitable for the thick layer pouring requirements of dam panels. Through the three-stage heating of preheating-insulation-curing, the problem of poor fluidity and high porosity of asphalt mixture under cooling is solved, and the surface density and water resistance and erosion resistance are greatly improved, blocking the water pressure leakage channel. Attached Figure Description

[0034] Figure 1 This is a schematic diagram of the layered temperature control mold structure of the present invention;

[0035] Figure 2 This is a schematic diagram of the layered temperature control mold surface heating wire structure of the present invention;

[0036] Figure 3 This is a schematic diagram of the layered structure of the anti-aging asphalt concrete panel of the present invention;

[0037] Figure 4 This is a flowchart of the concrete aggregate production process of this invention;

[0038] Figure 5 This is a flowchart of the process for preparing the anti-aging asphalt concrete panel of the present invention. Detailed Implementation

[0039] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0040] Example 1, please refer to Figures 1 to 5 The present invention provides a technical solution: a method for preparing an anti-aging asphalt concrete panel, step 1.1, the panel size is selected as 1m×1m×0.2m (bottom / middle / top layer 8cm, 8cm, 4cm respectively).

[0041] Step 1.2, Preparation of UV Absorbing Materials: 30nm anatase nano-titanium dioxide (purity 99.5%) and UV-327 (purity 98.5%, 100-mesh sieve), using 5-15mm ceramsite as a carrier (porosity 50%, compressive strength 4.0MPa), are dried at 105℃ for 24h, soaked in a stepped manner for 24h, and drained to a moisture content of 12% for later use; Asphalt concrete raw materials: 90# asphalt, limestone powder (fineness 0.075mm), lignin sulfonate water-reducing agent (diluted to 10%), and clean water; 5-15mm expanded perlite (porosity 55%, compressive strength 3.5MPa) is used for the bottom / middle layer, dried at 105℃ for 24h;

[0042] Step 1.3, Step-by-step preparation process: Preparation of supported aggregate: Take 14.0 kg of nano-titanium dioxide and UV-327 at a mass ratio of 1.5:1. 9.4 kg of material was dry-mixed for 2 minutes with 0.5% dispersant, then mixed with a water-to-material ratio of 1:3.5 for 6 minutes. The mixture was then immersed in 100 kg of carrier for 1.5 hours (22℃, low-speed stirring every 20 minutes). After removing the material and blowing out the pores, it was forced-dryed at 70℃ for 1.5 hours. No precipitation was observed after 48 hours of immersion, with a mass loss rate of 1.0% and an absorption rate of 89%. The bottom / middle layer was prepared with a mixture of 11% asphalt, 63% perlite, 23% mineral powder, 0.4% water-reducing agent, and 2.6% water, stirred at 152℃ for 3.5 minutes, controlling the slump at 60 mm and the temperature at 150℃. The surface layer replaced the aggregate with loaded ceramsite, with 0.15% silane coupling agent added, stirred at 148℃ for 2.8 minutes, achieving an absorption rate of 88.5%. The mold was coated with a release agent and preheated to 45℃. The bottom / middle layer was prepared at a ratio of 0.8 m... 3 / h pouring, vibrating with a vibrator for 45s, followed by heat preservation and standing for 25min / 18min; surface layer with 0.6m 3 The asphalt concrete panel is poured at / h, compacted twice with a plate vibrator (1MPa / 2.5MPa), cured at 145℃ for 35min, demolded, cured at 20℃ and 65% humidity for 7d, and then pretreated with water resistance for 72h.

[0043] Example 2, as Figures 1 to 5 As shown, based on Example 1, the present invention provides a technical solution: Step 2.1, the panel size is selected as 1m×1m×0.2m, the bottom layer thickness is 9cm, the middle layer thickness is 7cm, and the surface layer thickness is 4cm;

[0044] Step 2.2: The ultraviolet absorbing material is a ternary composite of nano-titanium dioxide, UV-327, and UV-360 in a mass ratio of 2:1:1, with a total filling weight of 72%. For every 100 kg of ceramsite carrier, the total material mass is 24 kg (12 kg titanium dioxide, 6 kg UV-327, and 6 kg UV-360). During paste preparation, the mixture is stirred at below 30℃ for 8 minutes, allowed to stand for 15 minutes until no bubbles appear, and then subjected to vacuum degassing at -0.08 MPa for 30 minutes with a depressurization rate of 0.015 MPa / min. The mixture is then dried using a stepped heating method. The finished aggregate is soaked for 72 hours.

[0045] Step 2.3, Layered pouring optimization: Bottom layer pouring speed 0.7m 3 / h, fabric thickness 11cm, vibration time 50s, settling time 30min; intermediate layer pouring speed 0.7m 3 The compaction process involves: 1 hour of compaction, 9 cm thick fabric, 40 seconds of vibration, and 20 minutes of settling. The surface curing temperature is controlled at 148℃, with a curing time of 38 minutes. The rolling pressure is increased to 3 MPa, and the compaction is performed three times. Temperature is monitored throughout the pouring process. If a temperature fluctuation (deviation of 3℃) occurs during surface curing, the temperature control equipment is immediately adjusted, and the curing time is extended by 8 minutes to ensure complete material setting. After cooling and solidification, the corresponding asphalt concrete panel is obtained.

[0046] Example 3, as Figures 1 to 5 As shown, based on Examples 1 and 2, the present invention provides a technical solution: Step 3.1, prepare panel size: 1m×1m×0.2m (bottom / middle / top layer 8cm, 8cm, 4cm respectively);

[0047] Step 3.2: The ultraviolet absorbing material uses a single UV-327 system with a 65% filling amount. 19 kg of material corresponds to 100 kg of ceramsite carrier. It is dried at 65℃ for 1.5 h, and the finished aggregate is soaked for 48 h. The asphalt concrete raw materials are: 90# asphalt, limestone powder, lignin sulfonate water-reducing agent (diluted to 10%), and water. The bottom / middle layer uses 5-15 mm expanded perlite (porosity 55%, compressive strength 3.5 MPa), which is dried at 105℃ for 24 h.

[0048] Step 3.3, Layered Temperature-Controlled Mold Casting and Curing: Mold preparation is the same as in Example 1. The vibration time for the bottom and middle layers is approximately 35 seconds, with resting times of 20 minutes and 15 minutes respectively. After the surface layer is cast, only plate vibration (approximately 30 seconds) is performed, without the need for roller compaction. The surface layer curing temperature is set at 140℃, and constant temperature curing is performed for 30 minutes. Step 3.3, a simplified vibration process is adopted for layered casting. The vibration time for the bottom / middle layers is 35 seconds, and the resting times are shortened to 20 minutes and 15 minutes respectively. The surface layer does not require compaction, only plate vibration for 30 seconds, curing temperature is 140℃, and curing time is 30 minutes. After demolding, it is cured at 20℃ and 65% humidity for 7 days, followed by 72 hours of water-resistant pretreatment. Then, it is repaired with epoxy resin mortar and cured for 24 hours to obtain the corresponding asphalt concrete panel.

[0049] The asphalt concrete panel specimens obtained in Examples 1, 2, and 3, as well as the asphalt concrete panel specimen obtained in the comparative example, were prepared under completely identical conditions and methods. The specimens were used to measure the ultraviolet absorption rate and panel aging rate. The specific test data are shown in the table below.

[0050]

[0051] As can be seen from the table above, the UV absorption rate and panel aging rate of the anti-aging asphalt concrete prepared by the method of the present invention are much higher than those of the comparative example. Therefore, the UV absorption rate and panel aging rate of the anti-aging asphalt concrete panel prepared by the method of the present invention are both high.

[0052] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0053] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A method for preparing an anti-aging asphalt concrete panel, wherein the panel has a total thickness of 20cm and adopts a three-layer structure, consisting of a bottom layer, a middle layer, and a top layer from bottom to top, with the bottom and middle layers having a total thickness of 16cm, wherein, The bottom layer is 7-9cm thick, the middle layer is 9-7cm thick, and the surface layer is fixed at 4cm. The core of the preparation involves the production of ultraviolet absorbing materials, asphalt concrete aggregates, panel structure, and mold casting. The specific steps are as follows: Step 1: Using honeycomb lightweight aggregate as a carrier, fill it with ultraviolet absorbing material and cure it to prepare water-resistant ultraviolet absorbing aggregate; Step 2: Prepare lightweight asphalt concrete aggregate for the bottom / middle layer and ultraviolet-absorbing asphalt concrete aggregate for the surface layer separately, and control the proportion of each group and the mixing process. Step 3: Create a layered temperature-controlled mold with heating wires, and pour the bottom / middle layer and the top layer of aggregate mixture in sequence. Then, it is vibrated, rolled and cured by precise temperature control heating. Step 4: After demolding, cure in a constant temperature and humidity environment, followed by long-term water immersion pretreatment to obtain the finished anti-aging asphalt concrete panel.

2. The method for preparing an anti-aging asphalt concrete panel according to claim 1, characterized in that: The ultraviolet absorbing material is a composite material composed of one or more of nano-titanium dioxide, ultraviolet absorber UV-327 or UV-360 in a predetermined mass ratio, wherein the nano-titanium dioxide has a particle size of 20-50 nm and a purity of ≥99%; The ultraviolet absorbing material is filled with 60%-80% of the pore volume of the carrier aggregate. After filling, it is fixed by low temperature drying at 60-80℃ for 1-2 hours, and verified by water immersion for 48 hours to ensure no material precipitation.

3. The method for preparing an anti-aging asphalt concrete panel according to claim 1, characterized in that: The components of the bottom / middle layer lightweight asphalt concrete aggregate, by mass percentage, include: 10%-12% asphalt, 60%-65% honeycomb lightweight aggregate, 20%-25% mineral powder, 0.3%-0.5% admixture, and 3%-5% water; The honeycomb lightweight aggregate is selected from at least one of expanded clay, expanded perlite, or foamed concrete aggregate. The particle size range of the honeycomb lightweight aggregate is 5-15 mm, the porosity is 40%-60%, and it is dried at 105℃ for 24 hours before selection. Its compressive strength is not less than 3 MPa.

4. The method for preparing an anti-aging asphalt concrete panel according to claim 3, characterized in that: The composition of the surface ultraviolet-absorbing asphalt concrete aggregate is consistent with the proportion of the bottom / middle layer lightweight asphalt concrete aggregate. The honeycomb lightweight aggregate in the bottom / middle layer lightweight asphalt concrete aggregate is replaced with an equal mass proportion of water-resistant ultraviolet-absorbing aggregate, and the amounts of asphalt, mineral powder and admixtures are adjusted accordingly to maintain the consistency of the total proportion.

5. The method for preparing an anti-aging asphalt concrete panel according to claim 4, characterized in that: The asphalt is selected from 70# or 90# petroleum asphalt. During the preparation process, it is heated to a molten state at 150-160℃ and mixed with other components at a stirring speed of 30-50r / min at 150-155℃ for 3-4 minutes. The additive is a lignin sulfonate water-reducing agent with a purity of not less than 95%, which is prepared into a 10% solution before use.

6. The method for preparing an anti-aging asphalt concrete panel according to claim 1, characterized in that: The layered temperature control mold is welded by a Q235 steel plate with a thickness of not less than 5 mm, and a high-temperature-resistant and corrosion-resistant metal heating wire is embedded at the bottom of the surface layer pouring chamber, the heating wire is a stainless steel wire or a nickel-chromium alloy wire, the temperature resistance is not less than 200 DEG C, the arrangement density is 5-8 roots / m 2 , and is connected with a temperature controller, and the temperature control precision is ±2 DEG C.

7. The method for preparing an anti-aging asphalt concrete panel according to claim 1, characterized in that: When pouring in layers, the pouring speed for the bottom and middle layers is 0.5-1m. 3 / h, and use a Φ50mm immersion vibrator at a spacing of 20-30cm to vibrate for 30-60s; Surface pouring speed: 0.5-0.7m 3 / h, after being vibrated on a plate, it is rolled 2-3 times with a pressure of 2-3MPa, and then heated and cured at 140-150℃ for 30-40min.

8. The method for preparing an anti-aging asphalt concrete panel according to claim 1, characterized in that: After demolding, the panel is placed in an environment with a temperature of 20±2℃ and a relative humidity of 60%-70% for 7 days of curing. It is allowed to cool naturally for no less than 24 hours before curing. During the curing period, the ambient temperature is maintained at 15-25℃. After curing, it is soaked for 72 hours for water resistance pretreatment.

9. The method for preparing an anti-aging asphalt concrete panel according to claim 1, characterized in that: The inner wall flatness error of the layered temperature control mold does not exceed 1mm / m, the size deviation of the finished panel is ≤±5mm, the surface flatness error is ≤2mm / m, and the appearance is free of cracks, missing corners, and pitting defects.

10. The method for preparing an anti-aging asphalt concrete panel according to claim 1, characterized in that: The prepared panel is adapted to dam conditions. The physical performance indicators of the panel include: weight reduction ratio ≥30%, surface density ≥96%, compressive strength ≥35MPa, ultraviolet absorption rate ≥85%, and after being subjected to the combined effects of 1000h ultraviolet aging and 720h water immersion, the compressive strength loss rate does not exceed 10%.

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