Road pavement structure and road heating snow-melting anti-cracking system

Abstract

The invention discloses a heating energy-storage snow-melting anti-cracking pavement structure system for a road. The system comprises a heat-conducting anti-cracking modified asphalt concrete surface layer, a temperature-adjusting emulsified asphalt macadam layer, a heating anti-cracking steel wire reinforced net, a heat-conducting anti-cracking asphalt concrete bottom layer, an energy-storage cement stable base layer, a PLC (Programmable Logic Controller), an energy storage battery, a solar panel and a temperature sensor. Through the heating function of the heating device, the whole road surface is heated, the road surface is uniformly heated, snow accumulation and icing on the road surface are prevented, and the ice and snow removing cost is reduced; the copper-plated steel fibers are added to the surface layer and the bottom layer of the asphalt concrete, so that the conductivity of the asphalt concrete is improved, and the heat-conducting capacity of the asphalt concrete is enhanced; graphite powder in the temperature-adjusting emulsified asphalt macadam layer has better uniform heat conduction performance, so that the emulsified asphalt macadam layer can form a uniform ultrathin heat conduction'panel '; a certain proportion of paraffin is added into the cement-stabilized base layer, the paraffin releases heat in a low-temperature state, and cracking caused by icing of water in the cement-stabilized base layer is prevented.

Description

Technical Field

[0001] The invention relates to a pavement structure, in particular to a road pavement structure and a road heating snow melting and crack prevention system. Background Art

[0002] In recent years, my country has experienced frequent freezing disasters, especially the freezing of asphalt pavements around the Spring Festival, which has caused a large number of returning passengers to be stranded or involved in traffic accidents, affecting social and economic stability. According to the traffic department's accident statistics, there are more traffic accidents at the end of the year and the beginning of the year. The main reason is that the ice layer on the surface of the road surface will cause the friction coefficient of the road surface to be significantly reduced, and the insufficient anti-skid ability of the road surface will cause the vehicle brakes to fail, resulting in accidents. In addition, most materials in nature have the phenomenon of "thermal expansion and contraction". Under the action of freezing, the asphalt pavement structure layer will shrink, and the tensile strength of the asphalt concrete material will decrease. When the tensile stress generated by the shrinkage of the asphalt surface layer exceeds the tensile strength of the material, a large number of cracks will appear in the asphalt surface layer. After the ice and snow melt, rainwater will penetrate into the pavement structure layer through the cracks, causing the asphalt concrete material to loosen and the pavement structure to be damaged.

[0003] Currently, de-icing methods are mainly divided into passive and active types.

[0004] Passive deicing mainly refers to deicing after snowfall and ice formation or when the snow on the road reaches a certain level. Traditional passive deicing methods for roads are mainly manual snow shoveling, mechanical snow scraping, and chemical snow melting. Manual snow shoveling is not only inefficient, but also very difficult to manually remove the ice layer on the road surface, and it is impossible to quickly eradicate the problem of road icing. The mechanical snow scraping method mainly uses machinery such as forklifts to de-ice the road surface. The mechanical deicing construction is rough, which often causes the surface layer of the road surface to be damaged, resulting in failure of the road surface structure. Although it can be opened to traffic in a short period of time, it leaves behind the sequelae of road damage, and a large amount of funds are required for repair in the later stage. Chemical snow melting is to spread chemical snow melting agents on the road surface in order to reduce the melting point of ice and snow, so that ice and snow remain in liquid form at a lower temperature. However, the large-scale use of snow melting agents will cause erosion of the road surface structure and damage the ecological environment such as soil, groundwater and trees.

[0005] Active deicing refers to taking effective measures to increase the temperature of the pavement structure before snowfall or during ice formation to prevent the road from freezing or quickly melting ice, and avoid the formation of an ice layer on the asphalt pavement. Currently, active deicing is mainly electric heating. A heating element is buried in the road structure. After power is turned on, the thermal effect of the heating element is used to increase the temperature of the road structure to prevent the road surface temperature from falling below the freezing point, and the heat inside the structure is transferred to the road surface to achieve the purpose of melting snow and ice. However, there are several typical problems with electric heating pavements: (1) Uneven heating leads to poor deicing effect In cold weather conditions, traditional asphalt pavements use embedded heating devices to prevent ice and snow accumulation. However, these devices often face the problem of uneven heating, resulting in unsatisfactory de-icing effect. This not only fails to effectively prevent ice accumulation on the road, but may also cause local stress concentration on the road surface, leading to damage to the asphalt pavement, further affecting the performance and service life of the pavement.

[0006] (2) Fatigue damage of heating wires When the heating power and heating material are the same, the rate of rise of the road surface temperature is inversely proportional to the burial depth, that is, the deeper the heating material is buried, the slower the road surface temperature rises, and the worse the deicing effect. Therefore, the burial depth of the heating wire should be as shallow as possible. In order to ensure the heating and thermal conductivity efficiency, the heating cables are laid on the asphalt surface. However, due to the large number of heavy loads on the highway, when the heating wire is subjected to the road load, the asphalt road surface is in anisotropy at this time, and the heating wire and the asphalt road surface have poor coordination deformation ability, which is easy to cause damage to the heating wire under repeated road loads.

[0007] (3) Durability issues of asphalt pavement Since the heating wire is set in the asphalt surface layer, it is equivalent to adding foreign matter into the asphalt mixture. Under the reciprocating action of load, the asphalt concrete will peel off from the heating wire, or squeeze with the heating wire, resulting in relative displacement inside the asphalt concrete. The relative displacement causes cracks inside, which are finally reflected to the road surface, thus destroying the overall strength of the asphalt concrete. If it is not repaired and replaced for a long time, the function of the asphalt pavement will decline, affecting the road driving safety.

[0008] (4) Temperature stress problem of asphalt pavement When heating and deicing in winter, due to the low temperature, the asphalt pavement structure, which is in a tensile stress state, releases tensile stress as the temperature gradually rises, and the asphalt concrete expands due to the heat, resulting in a large number of temperature cracks of varying sizes on the asphalt pavement. On rainy days, rainwater will penetrate into these cracks, causing the asphalt to separate from the stone surface, and the asphalt pavement to become loose and cracked.

[0009] (5) Cost issues of thermal asphalt pavement Heating asphalt pavement requires the embedding of specific heating elements and cables, and the use of a special asphalt mixture to ensure compatibility with the heating elements and the overall performance of the pavement, so the material cost is high. In addition, the operation of the heating device, especially in cold regions and when it is frequently used in winter, increases the electricity cost significantly. Summary of the invention

[0010] In order to solve the defects existing in the prior art, the present invention discloses a road pavement structure, which is characterized by: comprising, from top to bottom, a heat-conducting and crack-resistant modified asphalt concrete surface layer, a temperature-regulating emulsified asphalt gravel layer, a heat-generating and crack-resistant steel wire reinforcement mesh layer, a heat-conducting and crack-resistant asphalt concrete bottom layer, and an energy-storage cement concrete base layer.

[0011] The present invention also discloses a road heating energy storage snow melting and anti-cracking system, comprising a heat-conducting anti-cracking modified asphalt concrete surface layer, a temperature-adjusting emulsified asphalt gravel layer, a heating anti-cracking steel wire reinforcement mesh, a heat-conducting anti-cracking asphalt concrete bottom layer, an energy storage cement concrete base layer, a PLC programmable logic controller, an energy storage battery, a solar panel, and a temperature sensor, and is characterized by: The heat-generating anti-cracking steel wire reinforcement mesh layer is laid between the heat-conducting anti-cracking modified asphalt concrete surface layer and the heat-conducting anti-cracking asphalt concrete bottom layer, and a layer of temperature-adjusting emulsified asphalt chip seal is laid on the heat-generating anti-cracking steel wire reinforcement mesh; The energy storage cement concrete base is set under the heat-resistant cracking asphalt concrete base, which can store and release heat; The PLC programmable logic controller collects data from the temperature sensor and controls the power supply time and voltage when the temperature reaches below 0°C to achieve autonomous power supply; The energy storage battery stores solar energy, reduces dependence on traditional power grids, and supplies power to the steel wire reinforcement mesh; The solar panels collect the sun's radiant heat energy and convert solar energy into electrical energy; The temperature sensor is arranged in the surface layer of the heat-conductive and crack-resistant modified asphalt pavement to identify the surface temperature of the asphalt pavement, transmit the temperature data to the PLC programmable logic controller, and provide a temperature reference for the power supply time.

[0012] Beneficial Effects The heating function of the heating device can heat the entire road surface and evenly heat the road surface, effectively preventing snow and ice on the road surface and reducing the cost of snow and ice removal; The heat-generating and crack-resistant steel wire reinforcement mesh is made of metal material and galvanized on the surface. Compared with other heat-generating materials, it has high compressive and tensile strength, low strain capacity and corrosion resistance, and the structure has strong resistance to load fatigue damage; The heat-resistant crack-resistant steel wire reinforcement mesh is interlocked with the asphalt mixture and utilizes its own tensile strength to effectively balance the tensile stress generated by temperature, thereby effectively preventing the asphalt pavement from cracking due to internal temperature stress. Graphite powder is evenly distributed in the temperature-adjusting emulsified asphalt gravel layer, and the heat generated by the heat-generating and crack-resistant steel wire reinforcement layer is evenly transferred in the temperature-adjusting emulsified asphalt gravel layer, so that the temperature-adjusting emulsified asphalt gravel layer forms a uniformly heat-conducting "panel"; The energy storage cement concrete base is made by mixing paraffin wax with cement concrete. The paraffin wax is filled in the gaps between the cement concrete, which can store heat at high temperatures and release heat at low temperatures. At the same time, the internal moisture can be discharged through the hydrophobic properties of the paraffin wax.

[0013] The power transmission time and voltage are controlled by the PLC programmable logic controller, which effectively reduces the energy cost of power generation. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 This is a schematic diagram of the road heating energy storage snow melting and crack prevention pavement structure system of the present invention; Figure 2 This is a schematic diagram of the road heating snow melting and crack prevention system of the present invention; Figure 3 It is a schematic diagram of the road pavement structure; Figure 4 This is a schematic diagram of steel wire reinforcement; Figure 5 This is the structural dimension drawing of the steel wire reinforcement mesh; Figure 6 For the embedded physical picture; Figure 7 Actual picture of copper-plated steel fiber; Figure 8 Physical picture of graphite powder; Fig. 9 Actual picture of wire reinforcement mesh construction. DETAILED DESCRIPTION

[0015] See also Figure 1 As shown. The road heating energy storage snow melting and anti-cracking pavement structure system buries the heating anti-cracking steel wire reinforcement mesh at a certain depth below the road surface and arranges it in a specific way. After the external electrical energy is converted into thermal energy, the heat is transferred from bottom to top to the road surface and downward to the base layer to achieve the purpose of snow melting and ice melting. This technology buries the heating anti-cracking steel wire reinforcement mesh at the bottom of the thermal conductive anti-cracking modified asphalt surface layer, and the heating anti-cracking steel wire reinforcement mesh is arranged along the driving direction. After the electrical energy is input, the electrical energy is converted into thermal energy through the heating wire, and the road surface temperature is heated to above 0°C to ensure that the road surface does not freeze.

[0016] The electrical conductivity of the heat-generating anti-cracking steel wire reinforced mesh layer determines the heating efficiency. The heating power of the heat-generating anti-cracking steel wire reinforced mesh layer after power is applied can be calculated as follows: P = UI = I 2 R = U 2 / R (1) R =ρ l / s (2) P =( U 2 s ) / ρl (3) In the formula, P is the heating power; U is the applied voltage; I For the passage of current; R is the resistor; ρ is the resistivity; l is the distance between the external electrodes; s is the cross-sectional area of ​​the electrode at the contact point of the conductive functional layer.

[0017] Example 1 See also Figure 3 The present invention discloses a road pavement structure, which includes, from top to bottom, a heat-conducting anti-cracking modified asphalt concrete surface layer, a temperature-adjusting emulsified asphalt gravel layer, a heat-conducting anti-cracking steel wire reinforcement mesh layer, a heat-conducting anti-cracking asphalt concrete bottom layer, and an energy-storing cement concrete base layer.

[0018] Among them: The specific structure of the surface layer of thermal conductive and crack-resistant modified asphalt concrete is: the surface layer is 4cm thick, The material is asphalt mastic asphalt mixture (SMA-10), in which the asphalt is SBS (styrene-butadiene-styrene triblock copolymer) modified asphalt, the coarse aggregate is angular granite, the fiber is basalt fiber, the fine aggregate is limestone, the mineral powder filler is igneous rock, and the steel fiber is copper-plated steel fiber, with a single diameter of 0.2mm and a length of 8mm.

[0019] The dosage of each material (mass percentage of aggregate) is: SBS modified asphalt is 6.0%, basalt fiber is 0.3%, mineral powder filler is 8%, and copper-plated steel fiber is 2%.

[0020] Table 1 Mix ratio of surface stone materials for thermal conductive and crack resistant modified asphalt concrete

[0021] The main function of the surface layer of thermally conductive and crack-resistant modified asphalt concrete is to bear most of the driving dynamic loads and withstand the erosion of rain, ice and snow. In the process of low temperature environment, SBS modified asphalt can play a certain role in self-healing cracks. In addition, SBS modified asphalt has good high-temperature stability and a softening point of 80°C. After power is turned on and the temperature is raised, the asphalt mixture can still remain stable and not easy to soften and deform. It is integrated with the heat-generating and crack-resistant steel wire reinforcement mesh. Under the reinforcement of the steel wire mesh, it can resist the tensile stress caused by temperature and has a high crack resistance. At the same time, the copper-plated steel fibers in the asphalt mixture can better conduct the heat generated by the heating layer to the top surface of the surface layer. There is less loss during the heat transfer process, which has a good transfer effect.

[0022] The structure of the temperature-adjusting emulsified asphalt gravel layer is as follows: the overall thickness of the temperature-adjusting emulsified asphalt gravel layer is 1-2mm, in which the gravel is a single-size basalt with a particle size of 1-3mm; the emulsified asphalt is a PC-1 type cationic emulsified asphalt for spraying, and the graphite powder has an ash content of 0.16%, a water content of 0.10%, D 50 =12μm; the amount of each material (ratio to the total mass of the mixture) is: emulsified asphalt is 10%, basalt gravel is 86%, and graphite powder is 4%. The main function of the temperature-adjusting emulsified asphalt gravel layer is to evenly transfer the heat generated by the heat-generating and crack-resistant steel wire reinforcement mesh layer to the surface of the thermal conductive and crack-resistant modified asphalt concrete, prevent the surface of the thermal conductive and crack-resistant modified asphalt concrete from being unevenly heated and causing local low temperatures, effectively improve the overall heating performance of the surface of the thermal conductive and crack-resistant modified asphalt concrete, and prevent local freezing of the surface of the thermal conductive and crack-resistant modified asphalt concrete. In addition, emulsified asphalt can increase the adhesion strength between the asphalt surface and the bottom layer, so that the upper and lower layers can be more closely combined.

[0023] The structure of the heat-generating anti-cracking steel wire reinforcement mesh layer is: it is made of a double-twisted metal mesh, and the transverse copper main bars are woven into the mesh at a spacing of 16cm. The length of a single roll of the steel wire reinforcement mesh is 30m, and the roll width is 4m. In order to prevent the steel wire reinforcement mesh from being corroded by rainwater, the surface of the steel wire and the main bars are hot-dip galvanized. The main function of the heat-generating anti-cracking steel wire reinforcement mesh layer is: under power-on conditions, it uses its own resistance to generate heat, and can transfer heat to the surface of the heat-conducting anti-cracking modified asphalt concrete through the three-dimensional mesh structure, which has the effect of preventing the road surface from icing. At the same time, under the condition of large low-temperature stress, the heat-generating anti-cracking steel wire reinforcement mesh can effectively resist tensile stress and improve the anti-cracking ability of the surface of the heat-conducting anti-cracking modified asphalt concrete.

[0024] The bottom layer structure of heat-conducting anti-cracking asphalt concrete is as follows: the bottom layer thickness of heat-conducting anti-cracking asphalt concrete is 8cm, and the material is AC-25 asphalt mixture. Among them, the asphalt uses 70#A-grade road petroleum asphalt, the coarse aggregate is basalt, the fine aggregate is limestone, the mineral powder filler is limestone, and the steel fiber is copper-plated steel fiber, with a single diameter of 0.2mm and a length of 12mm. The dosage of each material (mass percentage of aggregate) is: asphalt is 4%, mineral powder filler is 5%, and copper-plated steel fiber is 1.5%. The function of the bottom layer of heat-conducting anti-cracking asphalt concrete is to transfer the driving dynamic load to the semi-rigid base layer and soil foundation together with the surface layer, and more importantly, to transfer the heat generated by the heat-generating anti-cracking steel wire reinforcement mesh layer downward to the lower structure layer to prevent the current layer and the lower structure layer from freezing at low temperature.

[0025] Table 2 Stone ratio of thermal conductive anti-cracking asphalt concrete base

[0026] The structure of the energy storage cement concrete base layer is as follows: the thickness of the energy storage cement concrete base layer is 18 cm, the cement addition amount is 6% of the total mass of the crushed stone, the melting point of paraffin is 49.45°C, the latent heat of phase change is 252.8 J / g, the paraffin addition amount is 2.5% of the total mass of the crushed stone, the final setting time of cement is less than 10 hours, the initial setting time is greater than 45 minutes, and the PO 42.5 specification is adopted.

[0027] Table 3 Stone ratio of energy storage cement concrete base

[0028] The function of the energy storage cement concrete base structure: it can absorb heat at high temperatures and store it in paraffin, and release the heat in the paraffin at low temperatures to prevent the cement concrete base from freezing and cracking, and it can also transfer heat to the asphalt concrete base to prevent the asphalt concrete base from freezing; at the same time, during the process of absorbing and releasing heat, paraffin can fill the pores in the cement concrete layer with the reciprocating transformation between solid and semi-liquid forms to prevent the rise of capillary water; paraffin has good hydrophobicity, which prevents moisture in the soil layer from migrating into the energy storage cement concrete layer; the energy storage cement concrete base has high compressive strength and flexural strength, which can withstand the load transmitted by the upper asphalt concrete structure, and disperse the load to the lower structure, reducing the stress transfer to the lower roadbed.

[0029] Example 2 Based on the road pavement structure in Example 1, the present invention also discloses a road heating snow melting and crack prevention system to solve the problems of asphalt pavement freezing, asphalt pavement fatigue cracking due to temperature and load stress, heating device fatigue damage and cost.

[0030] 1. Uniform heating of the road surface In traditional road snow melting and heating systems, heating devices usually use electric heating tubes, hot water circulation tubes, etc., but these devices have problems such as uneven heat conduction, high energy consumption and complex installation. Especially in cold areas, common electric heating devices cannot achieve uniform heating of the road surface, which can easily lead to local over-high or over-low temperatures on the road surface, thereby affecting the structural stability and durability of the road surface. Therefore, when designing the present invention, systematic improvements and optimizations were made to the core issue of how to achieve uniform heating of the road surface, and a series of innovative technical means and solutions were proposed, as follows: The innovative role and technical means of the heat-generating and crack-resistant steel wire reinforced mesh layer and the temperature-adjusting emulsified asphalt gravel layer: The present invention adopts a heat-generating anti-cracking steel wire reinforced mesh layer as a heating element, replacing the traditional electric heating tube or electric heating film. The heat-generating anti-cracking steel wire reinforced mesh itself not only has a high electrical conductivity, but can also be evenly distributed in the entire pavement structure, thereby forming a dense heating network. The heat-generating anti-cracking steel wire reinforced mesh layer is laid between the surface layer of the heat-conductive anti-cracking modified asphalt concrete and the bottom layer of the heat-conductive anti-cracking asphalt concrete. A 1-2mm temperature-adjusting emulsified asphalt gravel layer is laid on the heat-generating anti-cracking steel wire reinforced mesh layer. During the construction process, the heat-generating anti-cracking steel wire reinforced mesh layer is embedded in the bottom surface of the heat-conductive anti-cracking modified asphalt concrete surface layer. Through the roller rolling the heat-conductive anti-cracking modified asphalt concrete surface layer, the surface layer asphalt mixture is embedded and interlocked with the steel wire reinforced mesh to form an integral structure. At the same time, the heat-generating anti-cracking steel wire reinforced mesh is evenly laid with high density to cover the entire heating area to ensure the uniformity of heat transfer. The graphite powder added to the temperature-regulating emulsified asphalt gravel layer, after being evenly distributed in the emulsified asphalt, can produce a synergistic thermal response with the emulsified asphalt and gravel when the temperature changes, and regulate the absorption, conduction and dissipation of heat in a relatively consistent rhythm, forming a layer of evenly heated ultra-thin "panel".

[0031] Principle of solving the problem: ·Since the steel wire reinforcement mesh has high thermal conductivity and high heat capacity, when the current passes through the mesh, the heat can quickly diffuse to the entire road surface area. This design avoids the problem of local concentration of traditional heating pipes and can achieve uniform distribution of road surface temperature.

[0032] The reinforced mesh also enhances the structural strength of the pavement, avoiding cracks caused by thermal expansion and contraction due to temperature changes, thereby improving the durability of the pavement.

[0033] The temperature-controlled emulsified asphalt gravel layer can coordinate the absorption, conduction and dissipation of heat through the uniform heat transfer effect of graphite powder, making the asphalt surface layer heated more evenly and avoiding local heating "instability".

[0034] Technical verification and derivation: The heating effect of the steel wire reinforcement mesh was simulated through finite element heat conduction simulation analysis. The simulation results show that under the same power, the temperature distribution uniformity of the steel wire reinforcement mesh is significantly better than that of the traditional heating device. The specific performance is: Reduced temperature difference: The maximum temperature difference in the area covered by the steel wire reinforcement mesh is controlled within the range of ±1°C, while the temperature difference of traditional heating pipes can reach ±5°C.

[0035] Improved heating efficiency: The steel wire reinforced mesh structure can evenly increase the road surface temperature to the preset value in a shorter time (within 15 minutes), while traditional devices take more than 30 minutes.

[0036] Through on-site pavement experiments, the test section with steel wire reinforcement mesh installed can be evenly heated to 2-5°C in a low temperature environment, and no obvious temperature difference changes occur under continuous low temperature conditions (below -10°C), verifying the effect of uniform heating.

[0037] 2. Fine adjustment of intelligent control system (PLC controller).

[0038] Technical means: The PLC programmable logic controller in the present invention works in conjunction with the temperature sensor to monitor the road surface temperature in real time and dynamically adjust the voltage and power supply time according to the temperature change.

[0039] The PLC control system can control the heating power in different zones according to the temperature changes in different zones, achieve precise adjustment, and avoid energy waste and local temperature unevenness.

[0040] Principle of solving the problem: The temperature sensor is installed on the asphalt surface and can provide real-time feedback on the road surface temperature. The PLC controller accurately adjusts the power supply current of the steel wire reinforcement mesh based on the sensor data to achieve fine control of heating.

[0041] Through zone control, the PLC can adjust the voltage and current separately in different pavement areas, automatically compensating for temperature differences, thereby further improving the uniformity and efficiency of pavement heating.

[0042] Technical verification and derivation: Field tests show that the temperature distribution of the pavement system is more uniform after PLC zoning control, and the temperature fluctuation is controlled within ±0.5℃.

[0043] The simulation results further prove that partition control can significantly reduce energy consumption, saving about 20% of electricity compared to the traditional unified power supply mode.

[0044] Differences and advantages from background technologies Compared with the traditional heating device, the innovation of the present invention is mainly reflected in the following aspects: Innovative heating element design: using steel wire reinforced mesh instead of traditional heating tubes or electric heating films, it has higher thermal conductivity and structural strength, achieves uniform heating of the road surface, and enhances the road surface's crack resistance.

[0045] Multi-layer heat-conducting structure design: By laying a temperature-regulating emulsified asphalt gravel layer on the steel wire reinforcement mesh and adding thermal conductive material graphite powder to the temperature-regulating layer, the heat conduction efficiency is significantly improved, avoiding the local overheating problem common in traditional systems.

[0046] Intelligent control technology: integrated PLC controller and temperature sensor to achieve real-time dynamic adjustment of the heating system, further improving the system's response speed and temperature uniformity.

[0047] Energy-saving and environmental protection advantages: Through the design of solar panels and energy storage batteries, energy self-sufficiency is achieved, which greatly reduces the dependence on external electricity and has a higher energy utilization rate In cold regions, the road surface is prone to snow and ice accumulation, which increases the cost and difficulty of snow and ice removal. Through the heating function of the heating device, the road surface can be heated as a whole, the road surface can be evenly heated, and the snow and ice on the road surface can be effectively prevented, the cost of snow and snow removal can be reduced, and the safety and convenience of winter driving can be improved. Traditional electric heating pipes or hot water circulation pipes are usually laid under the roadbed or road surface at certain intervals. This design causes the heat source to be distributed linearly or point-wise rather than surface-wise. Since the heat source does not continuously cover the entire road surface, there are obvious "thermal gaps" in the transfer of heat on the road surface, which can easily cause the temperature in some local areas to be too high or too low. Uneven heat distribution can cause "hot spots" on the road surface, that is, areas with too high temperatures, which may aggravate the aging and softening of the asphalt material of the road surface. Areas with lower temperatures are prone to snow accumulation and ice formation, and the snow cannot be effectively melted, losing the expected effect of the heating device.

[0048] 3. Heating wire damage problem Steel wire reinforcement mesh is used as the heating material. The diameter of the mesh steel wire is 2.2mm, the diameter of the edge steel wire is 3.0mm, and the diameter of the copper main reinforcement is 4.6mm. In order to prevent the corrosion of the steel wire reinforcement mesh, anti-rust galvanized coating is used for protection. The galvanized coating amount is 280g / m 2 . Steel wire reinforcement mesh is a porous three-dimensional structure that can interlock with asphalt concrete, so that the steel wire reinforcement mesh and asphalt mixture can bear the road load together. In addition, the steel wire reinforcement mesh is made of metal material and the surface is galvanized. Compared with other heat-generating materials, it has high compressive and tensile strength, low strain capacity and corrosion resistance, and the structure has strong resistance to load fatigue damage.

[0049] 1 Three-dimensional porous structure design The present invention adopts a heat-generating and crack-resistant steel wire reinforcement mesh with a three-dimensional porous structure. The mesh structure not only provides mechanical strength, but also significantly improves the ability to evenly distribute heat. The specific analysis is as follows: 1.1 Three-dimensional porous structure interlocking principle: The steel wire reinforcement mesh adopts a diamond grid structure. This grid design can form a "mechanical interlocking" effect with asphalt concrete during the paving process. That is, the pores in the grid can be fully filled with concrete, causing friction and bite force between the reinforcement mesh and the concrete interface, thereby enhancing the overall stability of the structure.

[0050] The steel wires of the three-dimensional grid structure are processed by wave-shaped twisting to form more contact points and contact surfaces when combined with concrete, further increasing the interface strength and heat transfer efficiency.

[0051] 1.2 Galvanized steel wire improves durability The surface of the steel wire is treated with hot-dip galvanizing process, the thickness of the galvanized layer is controlled between 60-80 μm, and the galvanized coating amount is 280g / m 2 This thickness range provides good corrosion protection while ensuring that the thermal conductivity of the steel wire is not significantly affected.

[0052] Principles of galvanizing for corrosion protection and enhanced heat transfer: The galvanized layer has excellent anti-oxidation and corrosion resistance, which can prevent the steel wire from being corroded due to contact with moisture and road salt during long-term use. The presence of the galvanized layer can also reduce the formation of oxide layer on the metal surface, thereby reducing the interface thermal resistance and improving the heat transfer efficiency.

[0053] The microstructure of the galvanized surface presents a fine roughness, which can enhance the bonding strength between the steel wire and the concrete, making it difficult to loosen and fall off during thermal expansion and contraction, thus ensuring the long-term stability of the heating layer structure.

[0054] 2. Temperature-controlled emulsified asphalt gravel layer as heat conduction layer 2.1 Selection and optimization of temperature-controlled emulsified asphalt macadam layer materials The invention lays a temperature-adjusting emulsified asphalt gravel layer on the steel wire reinforcement mesh, wherein the material of the temperature-adjusting emulsified asphalt gravel layer is a mixture of graphite powder, PC-1 type cationic emulsified asphalt for spraying and fine-grained gravel.

[0055] The proportion of each material (total mass ratio of the mixture) is: 10% emulsified asphalt, 86% basalt crushed stone, and 4% graphite powder. This ratio ensures that the seal layer has good thermal conductivity (thermal conductivity coefficient is about 1.5-2.0 W / m·K) and good bonding performance, which can be closely combined with the steel wire reinforcement mesh to further improve the heat transfer effect.

[0056] 2.2 Uniform heating mechanism of the thermal conductive layer The existence of the temperature-regulating emulsified asphalt gravel layer not only protects the steel wire reinforcement mesh, but also acts as a heat spreader during the heating process. Since the mixed layer of graphite powder, emulsified asphalt and gravel has a high thermal conductivity, it can quickly absorb and diffuse the heat from the steel wire reinforcement mesh, making the temperature of the road surface more uniform.

[0057] The thickness of the temperature-controlled emulsified asphalt gravel layer is designed to be 1~2 mm, which can provide sufficient thermal conductivity without affecting the bearing capacity of the road surface.

[0058] 3. Multi-layer heat conduction structure design 3.1 Thermal Conductive Layer Structure and Thickness Design A double-layer heat-conducting structure is designed between the bottom layer and the surface layer of the heat-resistant asphalt concrete: The first layer is a heat-generating and crack-resistant steel wire reinforcement mesh and a temperature-regulating emulsified asphalt gravel layer, which is mainly responsible for initial heat conduction.

[0059] The second layer is a thermally conductive, crack-resistant modified asphalt concrete surface layer with a thickness of 4 cm. It has good heat dissipation performance and can further diffuse heat evenly.

[0060] Causes and principles of layered heat conduction: Through the layered design, the resistance to heat transfer in a single layer can be reduced, and the heat can be diffused layer by layer, thereby achieving a uniform heating effect on the entire road surface.

[0061] 3.2 Heat conduction model and verification Through heat conduction simulation analysis, the thermal diffusion coefficient of the double-layer heat-conducting structure is 0.85 m² / s, which is about 30% higher than that of traditional heating devices. Verification results show that this structural design can effectively improve the temperature uniformity of the road surface and reduce material aging problems caused by local excessive temperatures.

[0062] 3. Durability of asphalt pavement The technical solution of the present invention: the open grid structure of the steel wire reinforcement mesh fully engages with the asphalt mixture, so that each steel wire is combined with the surrounding asphalt aggregate into a whole, effectively enhancing the overall strength of the asphalt concrete surface layer itself and its ability to transfer loads.

[0063] The spacing S of the copper main reinforcement is 160mm, the horizontal width W of the mesh is 80mm, the longitudinal length L is 120mm, and the twisted edge length H is 40mm.

[0064] 4. Temperature stress problem of asphalt pavement Technical solution of the present invention: Due to the thermal expansion and contraction characteristics of the asphalt pavement material, significant temperature stress will be generated when the temperature changes. Especially in the low temperature environment in winter, when the temperature drops sharply, significant tensile stress effect will be generated inside the asphalt pavement, and the pavement material is prone to low-temperature cracks due to tensile stress exceeding its tensile strength. At the same time, the traditional heating snow melting system cannot ensure uniform heat transfer, which is easy to cause uneven temperature distribution of the pavement, thereby causing local thermal stress concentration, further exacerbating crack formation.

[0065] Material coordination deformation: The steel wire reinforcement mesh is interlocked with the asphalt mixture and uses its own tensile strength to effectively balance the tensile stress generated by temperature, thereby effectively preventing the asphalt pavement from cracking due to internal temperature stress. The steel wire reinforcement mesh structure and the asphalt concrete form an integral mechanical unit through a three-dimensional interlocking effect. The steel wire mesh has a certain degree of ductility and toughness, and can coordinate with the concrete to deform when the temperature changes, thereby reducing the difference in thermal expansion coefficients of different materials (approximately 20×10 -6 / ℃, steel is 11×10 -6 / ℃). Since the wire mesh is distributed in the middle of the pavement structure, it can disperse the temperature stress and spread the local temperature tensile stress to a larger range to avoid stress concentration.

[0066] Stress dispersion mechanism of three-dimensional porous structures:

[0067] The pores in the three-dimensional structure are designed to be 80mm×120mm. The existence of pores provides a spatial buffer for the thermal expansion and contraction of asphalt concrete, reducing stress concentration during expansion. The corrugated twisting design of the wire mesh (twisting angle is 30-45°) can absorb part of the thermal expansion stress and release it through the elastic deformation of the steel wire, thereby reducing the temperature stress of the overall structure.

[0068] The finite element thermal stress analysis model was used to simulate the stress distribution of the traditional asphalt pavement and the structure of the present invention when the temperature dropped to −20°C. The results showed that the temperature tensile stress of the pavement surface in the traditional structure was as high as 3 MPa, while after adopting the structure of the present invention, the temperature tensile stress dropped to 1.8 MPa, a reduction of about 40%.

[0069] 4. Cost issues of thermal asphalt pavement The technical solution of the present invention is as follows: the steel wire reinforcement mesh is mainly made of galvanized steel wires twisted and woven, and galvanized copper rods are added in the middle of the mesh, and the raw material cost is relatively low. In addition, the heating power supply mainly adopts solar power generation, and the power transmission time and voltage are controlled by the PLC programmable logic controller, which effectively reduces the energy cost of power generation.

[0070] The present invention aims at the problem of ice and cracking of asphalt pavement in winter. It adopts heat-generating and crack-resistant steel wire reinforcement mesh to generate heat and reinforce, which can melt ice and snow while preventing the pavement structure from cracking, and effectively solves the problem that related similar products can only melt ice and snow but cause serious cracking of the pavement.

[0071] 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 to the above embodiments. The above embodiments and descriptions only describe the principles of the present invention. The present invention may be subject to various changes and improvements without departing from the spirit and scope of the present invention. These changes and improvements fall within the scope of the present invention. The scope of protection claimed by the present invention is defined by the attached claims and their equivalents.

Claims

1. A road pavement structure, characterized by: It includes, from top to bottom: a heat-conducting and crack-resistant modified asphalt concrete surface layer, a temperature-regulating emulsified asphalt gravel layer, a heat-generating and crack-resistant steel wire reinforcement mesh layer, a heat-conducting and crack-resistant asphalt concrete bottom layer, and an energy-storage cement concrete base layer.

2. The road pavement structure according to claim 1, characterized in that: A certain amount of copper-plated steel fiber is added to the surface layer of the thermally conductive and crack-resistant modified asphalt concrete; a certain amount of copper-plated steel fiber is added to the bottom layer of the thermally conductive and crack-resistant asphalt concrete; the energy storage cement concrete base contains a certain amount of paraffin wax, which releases heat at low temperatures. At the same time, paraffin wax is hydrophobic, which prevents the cement concrete base from freezing while discharging interlayer water out of the layer.

3. The road pavement structure according to claim 2, characterized in that: The steel wire reinforcement mesh is protected by an anti-rust coating; the steel wire reinforcement mesh is designed as a porous three-dimensional structure and interlocked with the asphalt concrete; the steel wire reinforcement mesh is made of metal material and the surface is galvanized.

4. The road pavement structure according to claim 3, characterized in that: The open grid structure of the steel wire reinforcement mesh fully interlocks with the asphalt mixture, so that each steel wire is combined with the surrounding asphalt aggregate into a whole.

5. The road pavement structure according to claim 4, characterized in that: Graphite powder is evenly distributed in the temperature-controlled emulsified asphalt gravel layer. The graphite powder can evenly transfer the heat generated by the heat-resistant crack-resistant steel wire reinforcement layer in the temperature-controlled emulsified asphalt gravel layer, so that the temperature-controlled emulsified asphalt gravel layer forms an ultra-thin "panel" with uniform heat conduction; in addition, emulsified asphalt can make the asphalt surface layer and the bottom layer adhere together better, and improve the shear resistance of the upper and lower asphalt layer structures.

6. A road heating energy storage snow melting and crack prevention system, which is based on the road pavement structure described in claim 5, and includes a PLC programmable logic controller, an energy storage battery, a solar panel, and a temperature sensor, and is characterized by: The heat-generating anti-cracking steel wire reinforcement mesh layer is laid between the heat-conducting anti-cracking modified asphalt concrete surface layer and the heat-conducting anti-cracking asphalt concrete bottom layer, and is covered with an ultra-thin temperature-adjusting emulsified asphalt gravel layer. During the construction process, the heat-conducting anti-cracking modified asphalt concrete surface layer and the heat-generating anti-cracking steel wire reinforcement mesh layer are embedded together, and the heat-generating anti-cracking steel wire reinforcement mesh layer is embedded in the bottom surface of the asphalt concrete surface layer; The PLC programmable logic controller collects data from the temperature sensor and controls the power supply time and voltage when the temperature reaches below 0°C to achieve autonomous power supply; The energy storage battery stores solar energy to supply power to the heat-generating and crack-resistant steel wire reinforcement mesh; The solar panels collect the sun's radiant heat energy and convert solar energy into electrical energy; The temperature sensor is arranged in the surface layer of the heat-conductive and crack-resistant modified asphalt concrete to identify the surface temperature of the asphalt pavement, transmit the temperature data to the PLC programmable logic controller, and provide a temperature reference for the power supply time.

7. The road heating energy storage snow melting and crack prevention system according to claim 6 is characterized by: Galvanized copper rods are added in the middle of the steel wire reinforcement mesh, and the power transmission time and voltage are controlled by the PLC programmable logic controller to supply power to the copper rods.

8. The road heating energy storage snow melting and crack prevention system according to claim 7 is characterized by: The temperature-adjusting emulsified asphalt gravel layer is covered on the heat-generating anti-cracking steel wire reinforcement mesh layer, and has a thickness of 1 to 2 mm.

9. The road heating energy storage snow melting and crack prevention system according to claim 8 is characterized by: The structure of the reinforced mesh layer is: made of double-twisted metal mesh, with transverse copper main bars woven into the mesh at a spacing of 16cm; the single roll length of the steel wire reinforced mesh is 30m, and the roll width is 4m. In order to prevent the steel wire reinforced mesh from being corroded by rainwater, the surface of the steel wire and the main bars are hot-dip galvanized.

10. The road heating energy storage snow melting and crack prevention system according to claim 9 is characterized by: The surface thickness of the thermal conductive and crack-resistant modified asphalt concrete is 4 cm, and the materials are: asphalt mastic asphalt mixture SMA-10, in which the asphalt is styrene-butadiene-styrene triblock copolymer SBS modified asphalt, the coarse aggregate is angular granite, the fiber is basalt fiber, the fine aggregate is limestone, the mineral powder filler is igneous rock, and the steel fiber is copper-plated steel fiber; the dosage of each material, that is, the mass percentage of the aggregate is: SBS modified asphalt is 6.0%, basalt fiber is 0.3%, mineral powder filler is 8%, and copper-plated steel fiber is 2%; The bottom layer structure of the heat-conducting anti-cracking asphalt concrete is as follows: the bottom layer thickness of the heat-conducting anti-cracking asphalt concrete is 8cm, and the material is AC-25 asphalt mixture; the asphalt is 70#A-grade road petroleum asphalt, the coarse aggregate is basalt, the fine aggregate is limestone, the mineral powder filler is limestone, and the steel fiber is copper-plated steel fiber; the amount of each material, that is, the mass percentage of the aggregate is: asphalt is 4%, mineral powder filler is 5%, and copper-plated steel fiber is 1.5%; The thickness of the energy storage cement concrete base is 18 cm, the cement content is 6% of the total mass of the crushed stone, the melting point of paraffin is 49.45°C, the latent heat of phase change is 252.8 J / g, the paraffin content is 2.5% of the total mass of the crushed stone, the final setting time of cement is less than 10 hours, the initial setting time is greater than 45 minutes, and the PO 42.5 specification is adopted.

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