Road and bridge deck deicing system and method based on low-freezing-point asphalt concrete and geothermal energy piles

Abstract

The invention provides a road and bridge deck deicing system and method based on low-freezing-point asphalt concrete and geothermal energy piles. Comprising a low-freezing-point asphalt concrete pavement structure and a geothermal energy pile heat supply module. The low-freezing-point asphalt concrete pavement structure comprises an upper surface layer, a lower surface layer, a leveling layer, a waterproof layer and a bridge deck slab, wherein the upper surface layer is low-freezing-point asphalt concrete added with low-freezing-point capsules, phase change capsules and a heat conduction material; the phase change temperature of the phase change capsule is-3.5 DEG C to-2.5 DEG C, a preheating buffer period is provided for the geothermal energy pile heat supply module, the geothermal energy pile heat supply module comprises an energy pile, an underground heat exchange pipeline, a road surface heat exchange pipeline, a first water pump and a ground source heat pump, and the underground heat exchange pipeline and the road surface heat exchange pipeline are filled with heat exchange media and used for circularly conveying geothermal energy to the road surface. The phase change capsule is used for conducting buffering transition on geothermal heat transfer, ice and snow on the bridge floor are actively and rapidly removed, and the device has excellent construction adaptability and long-term use reliability.

Description

Technical Field

[0001] This invention belongs to the field of road construction technology, specifically relating to a road and bridge de-icing system and method based on low-freezing-point asphalt concrete and geothermal energy piles. Background Technology

[0002] In cold winter regions, bridge surfaces are highly susceptible to icing under conditions of low temperatures, snowfall, and rime, severely impacting road safety and frequently causing traffic accidents and structural damage. Compared to ordinary roads, bridge structures experience rapid heat exchange, resulting in faster and more severe icing on bridge surfaces, further threatening winter driving safety and causing traffic accidents.

[0003] Existing bridge de-icing technologies are mainly divided into two categories: passive de-icing technology and active de-icing technology.

[0004] Passive de-icing technologies mainly include manual removal and the spraying of de-icing agents. The former relies on manpower or machinery, resulting in slow response, low efficiency, and difficulty in completely removing ice and snow; while the latter can lower the freezing point, commonly used salt-based de-icing agents are corrosive to bridge structures and pollute the environment, making sustainable use difficult. Although passive de-icing methods are technically mature and simple to implement, they generally suffer from significant drawbacks such as slow response, high labor costs, and severe environmental pollution, making it difficult to meet the requirements of modern bridge safety and green development.

[0005] Active de-icing technologies mainly include elastic pavement de-icing, anti-icing coating technology, self-melting snow pavement technology, and thermal de-icing technology. Elastic pavement de-icing involves incorporating rubber particles into the surface asphalt, causing the ice layer to break up under vehicle load. However, this method suffers from insufficient bonding between the elastic material and the road surface, leading to peeling and poor durability over long-term use. Anti-icing coating technology involves spraying a coating composed of adhesives and snow-melting materials onto the bridge deck, giving it a certain snow-melting ability. However, this type of coating is prone to aging under the combined effects of long-term vehicle traffic, solar radiation, and contaminant adhesion, resulting in rapid performance degradation and a short service life. Self-melting snow pavement technology involves adding additives that release snow-melting components to the asphalt mixture, allowing it to actively release effective components in humid environments to lower the surface freezing point and achieve self-melting snow function. However, this type of low-freezing-point asphalt concrete suffers from low-temperature failure, meaning its de-icing ability is significantly reduced in extremely cold environments, limiting its application prospects in frigid regions. Thermal de-icing and snow removal technology utilizes heat sources such as electricity, solar energy, or geothermal energy to heat the road surface directly by laying heating wires, hot water pipe networks, conductive materials, or using microwaves, thus melting the ice and snow. Although this method has a good de-icing effect, in scenarios with large areas and heavy ice and snow, the heating time is long and the energy consumption is high, affecting its practical application. Clearly, active de-icing technology mainly achieves bridge deck de-icing through material modification or external heating sources, such as elastic pavement, anti-icing coatings, self-melting snow materials, and thermal de-icing systems. While these technologies have a certain degree of automation and intelligence, each individual technology always has issues related to energy consumption, efficiency, or durability.

[0006] In recent years, shallow geothermal energy, as a stable, renewable, and clean energy source, has been gradually introduced into the field of road de-icing. Transferring shallow geothermal energy to bridge deck pavement via a ground source heat pump system can achieve continuous heating without the need for high-power external energy input. Geothermal energy piles, as composite foundation components integrating structural load-bearing and heat exchange functions, have become a solution that combines space efficiency and energy utilization efficiency. Their internal heat exchange loops allow heat to exchange between the pile body, buried in the foundation soil, and the geothermal environment, thereby heating the bridge deck. This method features low energy consumption, high system stability, and good environmental adaptability.

[0007] However, due to the low temperature characteristics of shallow geothermal temperatures (usually 10~30℃), geothermal heating has a relatively slow response speed compared to electric de-icing technology, making it difficult to achieve rapid de-icing in a short time. At the same time, geothermal energy supply capacity is prone to insufficient heat transfer in extremely cold environments, which limits its applicability for independent operation.

[0008] In summary, current bridge de-icing technologies generally suffer from slow response, high energy consumption, and insufficient adaptability, making it difficult to fully meet the demands of modern bridges for efficient, low-carbon, and reliable de-icing systems in extremely cold environments. Especially under complex weather conditions, a single de-icing technology cannot simultaneously meet the requirements of immediacy, energy efficiency, and environmental friendliness. Therefore, there is an urgent need to develop a novel, environmentally friendly, and highly efficient composite bridge de-icing system that integrates multiple de-icing mechanisms to achieve rapid removal and long-term protection of ice and snow under different working conditions, thereby improving road safety. Summary of the Invention

[0009] The purpose of this invention is to provide a road and bridge de-icing system and method based on low-freezing-point asphalt concrete and geothermal energy piles. Phase change capsules and heat-conducting particles are added to the low-freezing-point asphalt concrete material, which works in conjunction with the geothermal de-icing method using energy piles. The geothermal method of energy piles raises the temperature of the bridge deck pavement to the working range of the low-freezing-point asphalt concrete, the heat-conducting particles make the heat transfer more uniform, and the phase change capsules provide a buffer for the geothermal heat transfer, thereby achieving active and rapid removal of ice and snow from the bridge deck and possessing excellent construction adaptability and long-term reliability.

[0010] To achieve the above objectives, the present invention provides a road and bridge de-icing system based on low-freezing-point asphalt concrete and geothermal energy piles, comprising: a low-freezing-point asphalt concrete pavement structure and a geothermal energy pile heating module. The low-freezing-point asphalt concrete pavement structure comprises, from top to bottom, a top layer, a bottom layer, a leveling layer, a waterproof layer, and a bridge deck. The top layer is made of low-freezing-point asphalt concrete with added low-freezing-point capsules, phase change capsules, and thermally conductive materials. The phase change capsules have a phase change temperature of -3.5 to -2.5°C and are used to form a cooling platform to provide a preheating buffer period for the geothermal energy pile heating module. The freezing point of the low-freezing-point capsules is -5.5 to -4.5°C. The geothermal energy pile heating module includes: an energy pile buried underground, an underground heat exchange pipe installed inside the energy pile, a road surface heat exchange pipe installed on the leveling layer, a first water pump, and a ground source heat pump. The underground heat exchange pipe and the road surface heat exchange pipe are filled with heat exchange medium for circulating and transporting geothermal energy to the road surface.

[0011] Furthermore, the shell of the low-freezing-point capsule is made of a hydrophobic material, and the core layer is one or more of an inorganic salt halide or an organic polyol compound. The inorganic salt halide includes one or more of sodium chloride, calcium chloride, potassium chloride, and magnesium chloride, preferably calcium chloride.

[0012] Furthermore, the shell of the phase change capsule is made of paraffin, and the core layer is made of an aqueous sodium chloride solution; The thermally conductive material is composed of graphite particles and alumina particles.

[0013] Furthermore, the low freezing point asphalt concrete is made by adding low freezing point capsules, phase change capsules, and thermally conductive materials to hot-mix AC type asphalt mixtures or MSA type anti-icing asphalt mixtures. The amount of the low freezing point capsule added is 4%-6% of the mass of mineral powder in the asphalt mixture, the amount of the phase change capsule added is 0.3%-0.6% of the mass of mineral powder, and the amount of the thermally conductive material added is 0.3%-0.6% of the mass of mineral powder.

[0014] Furthermore, the thickness of the upper layer is ≤5cm; the particle size of the low freezing point capsule is ≤0.075mm; The material of the lower layer is medium-grained asphalt concrete with a thickness of 4-6 cm.

[0015] Furthermore, the road and bridge de-icing system also includes an electric heating module, which includes a second water pump and an electric heating element. The second water pump, the electric heating element, and the road surface heat exchange pipe form a circulating heating pipeline. The electric heating element is used to heat the heat exchange medium in the road surface heat exchange pipe.

[0016] Furthermore, the road and bridge de-icing system also includes a temperature and humidity sensor, an icing sensor, a power supply module, and an intelligent control module. The intelligent control module collects and comprehensively analyzes the road surface temperature, ambient air temperature, inlet and outlet temperatures of the ground source heat pump, and icing status in real time, adjusts the heat pump operation status, and determines whether to activate the electric heating module.

[0017] This invention also provides a method for de-icing road and bridge surfaces based on low-freezing-point asphalt concrete and geothermal energy piles, comprising the following steps: When the road surface temperature sensor detects that the road surface temperature is higher than the phase change temperature of the phase change capsule and no icing occurs, the system shuts down silently, and the road surface is autonomously suppressed by low-freezing-point asphalt concrete to prevent surface icing. When the road surface temperature is detected to drop below the phase change temperature of the phase change capsule, the road surface temperature enters the phase change plateau period. At this time, the ground source heat pump and the first water pump are turned on to preheat the road surface.

[0018] At the same time, the heating capacity of the geothermal energy pile heating module is comprehensively evaluated based on changes in water temperature and road surface temperature. If the following three conditions are met simultaneously: 1. The outlet temperature of the ground source heat pump is ≥ T℃, where T is the preset temperature threshold. 2. The temperature difference between the outlet and inlet of the road surface heat exchange pipeline is ≥A℃, where A is the preset temperature difference threshold. 3. The road surface temperature rise rate is ≥ ΔB℃ / min, where ΔB is the preset temperature rise rate threshold; If the heating capacity of the geothermal energy pile heating module is sufficient, there is no need to turn on the electric heating module. If any of the above conditions are not met, the electric heating module will be activated to heat the heat exchange medium in the road surface heat exchange pipeline.

[0019] Furthermore, when the road surface temperature is less than or equal to the phase change temperature and greater than or equal to the freezing point of the low-freezing-point capsule, the geothermal energy pile heating module is used for heating. If the road surface temperature is still showing a downward trend during this period, the electric heating module is activated for temperature compensation.

[0020] In summary, compared with the prior art, the present invention has the following main technical advantages and beneficial effects: 1. This invention incorporates phase change capsules and heat-conducting particles into low-freezing-point asphalt concrete materials, which, in conjunction with the geothermal de-icing method using energy piles, raises the bridge deck pavement temperature to within the working range of low-freezing-point asphalt concrete. The heat-conducting particles ensure more uniform heat transfer, and the phase change capsules provide a buffer for geothermal heat transfer, enabling active and rapid removal of ice and snow from the bridge deck. This invention also exhibits excellent construction adaptability and long-term reliability.

[0021] 2. The slow release of low-freezing-point active ingredients is controlled through low-freezing-point capsules. The low-freezing-point material lowers the freezing point of the road surface, while the hydrophobic material reduces water penetration into the road surface, improves the wetting state between water and the road surface, and reduces the adhesion of ice to the road surface.

[0022] 3. In cases of light snowfall, the anti-icing pavement of this invention can directly melt the snow on the road surface; in cases of heavy snowfall, it can melt the snow layer in direct contact with the road surface; due to the low freezing point and water-repellent properties of the anti-icing pavement, water will not freeze again on the road surface, and the ice and snow on the road surface can be easily removed, achieving the application effect of "light snow melts, heavy snow is easy to remove".

[0023] 4. This invention collects and analyzes road surface temperature, ambient air temperature, ground source heat pump inlet / outlet water temperature, and bridge deck icing status in real time. Based on preset control logic, it intelligently adjusts the ground source heat pump operation status and dynamically determines whether to activate the electric heating auxiliary system, thereby achieving an efficient and precise control strategy for the coordinated de-icing of "geothermal energy piles + low freezing point asphalt concrete pavement". Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the overall structure of a road and bridge de-icing system based on low-freezing-point asphalt concrete and geothermal energy piles. Figure 2 A schematic diagram of a low-freezing-point asphalt concrete pavement structure; Figure 3 This is a schematic diagram of the layout structure of the road surface heat exchange pipeline; Figure 4 for Figure 1 The left view; Figure 5 for Figure 1 The front view; Figure 6 This is a schematic diagram of the heat exchange structure of a ground source heat pump. Detailed Implementation

[0025] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0026] Please see Figure 1-5 The present invention provides a road and bridge surface de-icing system based on low-freezing-point asphalt concrete and geothermal energy piles, comprising: a low-freezing-point asphalt concrete pavement structure and a geothermal energy pile heating module. The low-freezing-point asphalt concrete pavement structure comprises, from top to bottom, a top layer, a bottom layer, a leveling layer, a waterproof layer, and a bridge deck. The top layer is made of low-freezing-point asphalt concrete with added low-freezing-point capsules, phase change capsules, and thermally conductive materials. The phase change capsules have a phase change temperature of -3.5 to -2.5°C and are used to form a cooling platform to provide a preheating buffer period for the geothermal energy pile heating module. The freezing point of the low-freezing-point capsules is -5.5 to -4.5°C. The geothermal energy pile heating module includes: an energy pile buried underground, an underground heat exchange pipe installed inside the energy pile, a road surface heat exchange pipe installed on the leveling layer, a first water pump, and a ground source heat pump. The underground heat exchange pipe and the road surface heat exchange pipe are filled with heat exchange medium for circulating and transporting geothermal energy to the road surface.

[0027] This operation, by adding phase change capsules and heat-conducting particles to low-freezing-point asphalt concrete materials, and then coordinating with the geothermal de-icing method using energy piles, raises the bridge deck pavement temperature to the working range of low-freezing-point asphalt concrete using the geothermal method of energy piles, makes heat transfer more uniform using the heat-conducting particles, and uses phase change capsules to buffer the transition of geothermal heat transfer, thereby achieving active and rapid removal of ice and snow from the bridge deck, and has excellent construction adaptability and long-term reliability.

[0028] Specifically, such as Figure 2 Low freezing point asphalt concrete pavement structure design: Based on the bridge deck asphalt pavement structure, from top to bottom, the following are the structural designs: Surface layer: The top layer is generally fine-grained asphalt concrete, 3-4cm thick, which plays a role in anti-skid and wear resistance. In this invention, low-freezing-point asphalt concrete is used as the main material. By adding functional low-freezing-point capsules to the traditional asphalt mixture, the surface material has the ability to automatically reduce the freezing point of the bridge surface and melt snow. At the same time, a certain proportion of phase change capsules and heat-conducting particles are added to improve the heat exchange efficiency.

[0029] The lower layer: medium-grained asphalt concrete with a traditional design, typically 4-6cm thick, serves to transmit force and bear load.

[0030] Leveling layer, waterproof layer and bridge deck: The traditional structure remains unchanged. In this invention, the leveling layer serves as the laying layer for the heat exchange pipes. During the laying process, the heat exchange pipes are evenly distributed in the key wheel track area of ​​the bridge deck (i.e., the vehicle's usual driving path). Low-freezing-point asphalt concrete: This low-freezing-point asphalt concrete is a well-known asphalt concrete material. The nominal maximum particle size of the low-freezing-point material is 0.075mm. It is mainly composed of hydrophobic materials and low-freezing-point materials (inorganic halides or organic polyol-based compounds), and has a microscopic core-shell capsule structure (low-freezing-point capsules). The outer layer is wrapped with a thin shell structure, which can control the slow release of the internal low-freezing-point effective components. Among them, the low-freezing-point material plays the role of lowering the freezing point of the road surface; while the hydrophobic material can reduce the ability of water to penetrate into the interior of the road surface, improve the wetting state between water and the road surface, and reduce the adhesion between ice and the road surface.

[0031] In cases of light snowfall, anti-icing pavement can directly melt snow on the road surface; in cases of heavy snowfall, it can directly melt the snow layer in contact with the road surface. Due to the low freezing point and hydrophobic properties of anti-icing pavement, water will not refreeze on the road surface, and ice and snow on the road surface are easily removed. It achieves the effect of "melting light snow and easily removing heavy snow." At the same time, it has no impact on the road structure or surrounding vegetation, with a seed damage rate of less than 15%, exceeding national standards, and resulting in low environmental pollution.

[0032] Anti-icing pavement typically involves adding low-freezing-point materials to the top layer (≤5cm) of ordinary asphalt concrete pavement to achieve the anti-icing effect. Taking winter-temperature zones as an example, the design requirement for low-freezing-point asphalt mixtures is a freezing point not exceeding -5 degrees Celsius. When the ambient temperature drops below -5 degrees Celsius, the anti-icing pavement fails.

[0033] This invention provides a specific implementation method, for example, in the preparation of hot-mix anti-icing asphalt concrete. Based on the original ordinary asphalt concrete, a low-freezing-point material (low-freezing-point capsule) is added in the form of replacing mineral powder. The addition ratio in hot-mix AC and MSA type anti-icing asphalt mixtures is 4% to 6% of the total mass of the mineral aggregate. However, it should be noted that the low-freezing-point pavement involved in this invention refers to all asphalt concrete pavements using this type of de-icing principle, and not to a specific proportion of low-freezing-point asphalt concrete. Commonly used inorganic salts in low-freezing-point asphalt concrete (the core layer of the low-freezing-point capsule) include sodium chloride, calcium chloride, potassium chloride, and magnesium chloride. Generally, calcium chloride is more effective because it has better water absorption, allowing it to absorb and dissolve moisture from the air more quickly, thus lowering the freezing point of water.

[0034] Simultaneously, in the low-freezing-point pavement material described in this invention, 0.5% (relative to the aggregate) of phase change capsules and 0.5% (relative to the aggregate) of thermally conductive particles are incorporated in proportion. The outer layer of the phase change capsule adopts a paraffin shell structure, and the inner layer is a sodium chloride aqueous solution in a certain proportion. Its phase change temperature is controlled at about -3°C, which can form a stable cooling plateau stage before and after the bridge surface temperature approaches the freezing point, and also provide sufficient preheating time for the geothermal system, avoiding a reduction in de-icing efficiency due to system start-up lag. The thermally conductive particles are preferably graphite particles and alumina particles, used to improve the overall thermal conductivity of the low-freezing-point asphalt concrete and ensure the uniform distribution of heat in the pavement structure.

[0035] When the bridge deck temperature drops to -3℃, the heat absorption process of the phase change material forms a "cooling plateau". While maintaining the bridge deck temperature from dropping further rapidly, it provides a valuable time window for the start-up and heating of the geothermal system, thus eliminating the need for additional preheating and significantly improving the system response efficiency.

[0036] Regarding energy piles, ground source heat pumps, and underground heat exchange pipes: This invention uses energy piles to replace the traditional bridge pile foundation structure. The energy piles are driven into the ground, with the specific burial depth determined based on geological conditions. U-shaped or W-shaped underground heat exchange pipes are installed inside the energy piles to fully exchange heat with the surrounding foundation soil, increasing the temperature of the circulating working fluid. The underground heat exchange pipes connect to the first water pump and the ground source heat pump from the pile. The outlet of the ground source heat pump is connected to an intelligent control module, which regulates the start and stop of the water pump and heat pump through control logic. The geothermal heat exchange fluid (i.e., the heat exchange medium, such as a water / ethylene glycol mixture (antifreeze) to prevent freezing in severe cold) is heated by the heat pump and then transported to the U-shaped, flat-paved road surface heat exchange pipes buried within the bridge deck leveling layer, preferably laid along the wheel tracks of the lanes to ensure priority heating of key areas.

[0037] Specifically, the road and bridge surface de-icing system also includes an electric heating module, which comprises a second water pump and an electric heating element (such as...). Figure 6The heating element on the right side of the road surface, the second water pump, the electric heating element and the road surface heat exchange pipe form a circulating heating pipeline, and the electric heating element is used to heat the heat exchange medium in the road surface heat exchange pipe.

[0038] like Figure 6 As shown, a ground source heat pump mainly includes a compressor, evaporator, and condenser. The underground heat exchange pipeline connects to a water pump and flows from the underground pipeline inlet through the evaporator, then returns to the underground heat exchange pipeline from the underground pipeline outlet. The surface heat exchange pipeline connects to a water pump and flows from the surface pipeline inlet through the condenser, then returns to the surface heat exchange pipeline from the surface pipeline outlet. Electric heating elements are installed in the surface heat exchange pipeline loop. The two pipelines of the geothermal energy pile heating module and the electric heating module are not interconnected. The ground source heat pump unit is responsible for converting the heat from the underground pipeline heat exchange fluid into the high-temperature heat exchange fluid of the surface pipeline through components such as the compressor, evaporator, and condenser. This is because the temperature of the underground pipeline is relatively low, requiring the ground source heat pump to compress it to a higher temperature to meet the requirements. Additionally, in special circumstances, the heat extracted by the ground source heat pump from underground is limited, resulting in a decrease in heating efficiency. In this case, electric heating serves as an auxiliary heat source, directly heating the circulating fluid in the surface loop to ensure the temperature meets the requirements.

[0039] Specifically, cold water flows in from an underground heat exchange system. The blue arrows in the diagram indicate the direction of water flow. This water originates from underground pipes, absorbing heat from the ground as it flows past the energy piles, becoming warmer water. This warmer water then enters the system's evaporator. In the evaporator, heat is transferred to the working liquid, causing it to evaporate into a gas. At this point, heat is absorbed, and the working liquid transforms from a liquid state into a low-temperature, low-pressure gas.

[0040] Compressor: Low-temperature, low-pressure gases are compressed by the compressor. The function of the compressor is to significantly increase the temperature and pressure of the gas, compressing low-temperature gas into high-temperature, high-pressure gas.

[0041] Condenser: High-temperature, high-pressure gas enters the condenser, where it releases the absorbed heat through heat exchange with the above-ground pipelines, cooling down into a liquid. During this process, water in the above-ground pipelines is heated to increase its temperature and then used to irrigate the road surface, serving as the primary source of heating.

[0042] Expansion valve: The high-pressure liquid from the condenser is depressurized by the expansion valve. The expansion valve reduces the liquid pressure, allowing the liquid to re-enter the evaporator, ready for the next heat exchange process.

[0043] Specifically, the road and bridge de-icing system also includes a sensor module: temperature, humidity, and icing sensors are deployed in several key areas of the bridge surface, while temperature sensors are installed at the outlet of the ground source heat pump and at the inlet and outlet of the road surface heat exchange pipes to ensure comprehensive data collection and real-time response. The sensors interact with the intelligent control module via cables.

[0044] System power supply module: The power required by the water pump unit is provided by the control box, which can be connected to the mains power or connected to a wind-solar hybrid new energy system to enhance system independence.

[0045] Intelligent Control Module: As the system control center, it integrates core components such as a control chip, power management unit, and communication module. By collecting and comprehensively analyzing real-time data on road surface temperature, ambient air temperature, ground source heat pump inlet / outlet water temperature, and bridge deck icing status, it intelligently adjusts the ground source heat pump's operating status according to preset control logic and dynamically determines whether to activate the electric heating auxiliary system. This achieves a highly efficient and precise control strategy for the coordinated de-icing of "geothermal energy piles + low-freezing-point asphalt concrete pavement".

[0046] The present invention provides a method for de-icing road and bridge surfaces based on low-freezing-point asphalt concrete and geothermal energy piles, comprising the following steps: When the road surface temperature sensor detects that the road surface temperature is higher than the phase change temperature of the phase change capsule (e.g., -3℃) and no icing occurs, the system shuts down silently, and the road surface is autonomously suppressed by low-freezing-point asphalt concrete to prevent surface icing. When the road surface temperature is detected to drop below the phase change temperature of the phase change capsule, the road surface temperature enters the phase change plateau period. At this time, the system automatically enters the de-icing mode, turns on the ground source heat pump and the first water pump to preheat the road surface: the geothermal circulation system is started, and the fixed frequency water pump runs continuously at the maximum flow rate. Simultaneously assess the heating capacity of the geothermal system. If all three of the following conditions are met: 1. The outlet temperature of the ground source heat pump is ≥ T℃, where T is the preset temperature threshold. 2. The temperature difference between the outlet and inlet of the road surface heat exchange pipeline is ≥A℃, where A is the preset temperature difference threshold. 3. The road surface temperature rise rate is ≥ ΔB℃ / min, where ΔB is the preset temperature rise rate threshold; If the heating capacity of the geothermal energy pile heating module is sufficient, there is no need to turn on the electric heating module. If any of the above conditions are not met, the electric heating module will be activated to heat the heat exchange medium in the road surface heat exchange pipe, increase the inlet water temperature, and ensure that the bridge deck temperature quickly reaches the working temperature of the low freezing point asphalt concrete pavement.

[0047] When the bridge deck temperature rises to between the phase change temperature and the freezing point of the low-freezing capsule (e.g., -5.5℃ to -4.5℃), the system automatically switches to heat preservation mode: maintaining the stable operation of the geothermal system, with the water pump continuously supplying heat at the rated flow rate.

[0048] During this phase, geothermal heating is used to maintain the bridge deck temperature. If the bridge deck temperature is still showing a downward trend, the system will restart electric heating to compensate for the temperature and ensure that the bridge deck temperature remains stable within the effective working temperature range of the low freezing point asphalt concrete material.

[0049] If the bridge deck temperature tends to drop, the system will turn on the electric heating again to ensure that the road surface temperature does not fall below the working critical value of the low freezing point material.

[0050] Those skilled in the art will readily understand that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A road and bridge surface de-icing system based on low-freezing-point asphalt concrete and geothermal energy piles, characterized in that, include: Low freezing point asphalt concrete pavement structure and geothermal energy pile heating module; The low-freezing-point asphalt concrete pavement structure comprises, from top to bottom, a top layer, a bottom layer, a leveling layer, a waterproof layer, and a bridge deck. The top layer is made of low-freezing-point asphalt concrete with added low-freezing-point capsules, phase change capsules, and thermally conductive materials. The phase change capsules have a phase change temperature of -3.5 to -2.5°C and are used to form a cooling platform to provide a preheating buffer period for the geothermal energy pile heating module. The freezing point of the low-freezing-point capsules is -5.5 to -4.5°C. The geothermal energy pile heating module includes: a first water pump, a ground source heat pump, an energy pile buried underground, an underground heat exchange pipe installed inside the energy pile, and a road surface heat exchange pipe installed on the leveling layer. The underground heat exchange pipe and the road surface heat exchange pipe are filled with heat exchange medium for circulating and transporting geothermal energy to the road surface.

2. The road and bridge surface de-icing system based on low-freezing-point asphalt concrete and geothermal energy piles according to claim 1, characterized in that, The shell of the low-freezing-point capsule is made of a hydrophobic material, and the core layer is one or more of inorganic salt halides and organic polyol compounds. The inorganic salt halides include one or more of sodium chloride, calcium chloride, potassium chloride, and magnesium chloride.

3. The road and bridge de-icing system based on low-freezing-point asphalt concrete and geothermal energy piles according to claim 2, characterized in that, The shell of the phase change capsule is made of paraffin, and the core layer is an aqueous solution of sodium chloride. The thermally conductive material is composed of graphite particles and alumina particles.

4. The road and bridge surface de-icing system based on low-freezing-point asphalt concrete and geothermal energy piles according to claim 3, characterized in that, The low freezing point asphalt concrete is made by adding low freezing point capsules, phase change capsules and thermally conductive materials to hot-mix AC type asphalt mixture or MSA type anti-icing asphalt mixture. The amount of the low freezing point capsule added is 4%-6% of the mass of mineral powder in the asphalt mixture, the amount of the phase change capsule added is 0.3%-0.6% of the mass of mineral powder, and the amount of the thermally conductive material added is 0.3%-0.6% of the mass of mineral powder.

5. The road and bridge de-icing system based on low-freezing-point asphalt concrete and geothermal energy piles according to claim 1, characterized in that, The thickness of the top layer is ≤5cm; the particle size of the low freezing point capsule is ≤0.075mm; The material of the lower layer is medium-grained asphalt concrete with a thickness of 4-6 cm.

6. The road and bridge surface de-icing system based on low-freezing-point asphalt concrete and geothermal energy piles according to any one of claims 1-5, characterized in that, The road and bridge de-icing system also includes an electric heating module, which includes a second water pump and an electric heating element. The second water pump, the electric heating element, and the road surface heat exchange pipe form a circulating heating pipeline. The electric heating element is used to heat the heat exchange medium in the road surface heat exchange pipe.

7. The road and bridge surface de-icing system based on low-freezing-point asphalt concrete and geothermal energy piles according to claim 6, characterized in that, The road and bridge de-icing system also includes a temperature and humidity sensor, an icing sensor, a power supply module, and an intelligent control module. The intelligent control module collects and analyzes in real time the road surface temperature, ambient air temperature, the inlet and outlet temperatures of the ground source heat pump, and the icing status to adjust the heat pump operation status and determine whether to activate the electric heating module.

8. A method for de-icing road and bridge surfaces based on low-freezing-point asphalt concrete and geothermal energy piles, employing the road and bridge surface de-icing system based on low-freezing-point asphalt concrete and geothermal energy piles as described in claim 6 or 7, characterized in that, Includes the following steps: When the road surface temperature is detected to be higher than the phase change temperature of the phase change capsule and no icing occurs, the system shuts down silently, and the road surface is autonomously suppressed by low-freezing-point asphalt concrete to prevent surface icing. When the road surface temperature drops to less than or equal to the phase change temperature of the phase change capsule, the road surface temperature enters the phase change plateau period. At this time, the ground source heat pump and the first water pump are turned on to preheat the road surface.

9. The method for de-icing road and bridge surfaces based on low-freezing-point asphalt concrete and geothermal energy piles according to claim 8, characterized in that, Also includes: The heating capacity of the geothermal energy pile heating module is comprehensively evaluated based on changes in water temperature and road surface temperature. If the following three conditions are met simultaneously:

1. The outlet temperature of the ground source heat pump is ≥ T℃, where T is the preset temperature threshold.

2. The temperature difference between the outlet and inlet of the road surface heat exchange pipeline is ≥A℃, where A is the preset temperature difference threshold.

3. The road surface temperature rise rate is ≥ ΔB℃ / min, where ΔB is the preset temperature rise rate threshold; If the heating capacity of the geothermal energy pile heating module is sufficient, there is no need to turn on the electric heating module. If any of the above conditions are not met, the electric heating module will be activated to heat the heat exchange medium in the road surface heat exchange pipeline.

10. The method for de-icing road and bridge surfaces based on low-freezing-point asphalt concrete and geothermal energy piles according to claim 8, characterized in that, When the road surface temperature is less than or equal to the phase change temperature and greater than or equal to the freezing point of the low freezing point capsule, the geothermal energy pile heating module is used for heating. If the road surface temperature is still showing a downward trend during this period, the electric heating module is turned on for temperature compensation.

Images