| The problem of snow and ice on roads has been plaguing most of China.Snow and ice on roads cause a large number of traffic accidents every year,which hinders traffic operation and seriously affects social public safety.The traditional method of deicing is inefficient,environmental pollution and requires a lot of manpower input,which has been unable to meet the needs of the rapid development of modern society.Aiming at the problems of short life and high energy consumption of heating materials in electric heating active ice and snow removal technology,this paper relies on the key research and development projects of the national key research and development project and the key research and development project of the Science and Technology Department of Jilin Province.By optimizing raw materials such as carbon fiber cloth,vulcanizing agent and graphite,a new type of electric heating conductive rubber composite material with“targeted heat transfer”function was developed and prepared by adopting the method of hierarchical design and recombination.The integrated design of conductive rubber composite material-paving structure was carried out by indoor and outdoor tests and numerical simulation.A new type of active electric heating deicing technology with conductive rubber composite material as heat source was formed,and the technology was successfully applied to actual engineering,aiming at realizing the road green,low energy consumption,real-time,safe,and intelligent deicing target.The main research contents and conclusions are as follows:(1)Preparation and performance test of conductive rubber composite material.A new type of conductive rubber composite material was prepared by plate vulcanization method using 12k carbon fiber cloth as heat producing layer,thermal conductive ethylene propylene diene monomer rubber as heat transfer layer,ethylene propylene diene monomer rubber and aluminum silicate fiber cloth as heat insulation layer.The resistance characteristics,thermal properties,and mechanical properties of the composites were tested by indoor tests.The results showed that the resistance of composite material was less affected by temperature,input voltage and time effect,and the maximum change rate did not exceed 5.25%.When the input power was 1000W/m~2,the surface temperature of composite material was increased by 58.5°C after heating for 60 minutes.The compressive strength of the composite was 3.88MPa,the tensile strength was 6.44MPa,and the tear strength was 16.52k N/m.(2)Durability and deformation stability analysis of conductive rubber composite material.The mechanical and thermal durability of conductive rubber after complex environmental effects such as load,temperature,water and snowfall under multiple working conditions were studied by indoor tests.The results showed that after20h wheel load tests,the compressive strength of composite material increased by14.95%,the tensile strength decreased by 1.09%,the tear strength remained unchanged,and there was no obvious degradation of mechanical properties.After the composite material was subjected to load and complex environment,the elastic modulus changed little,and the maximum elastic modulus was reduced by 10.77%compared with the initial elastic modulus,which had deformation stability.The resistance fluctuation of composite material under the multi-snow melting conditions was small,and the maximum change rate was not more than 4%,which had resistance stability.(3)Performance analysis of conductive rubber composite pavement structure.Through numerical simulation,the composite material was laid inside the pavement structure and bridge deck pavement structure,and the finite element model of three-dimensional conductive rubber composite paving structure was established.The structural response of conductive rubber composite pavement under three different load conditions was analyzed.At the same time,the influence of laying composite materials on the performance of bridge deck pavement structure was evaluated.The results showed that the best laying position of composite material in the road structure was under the asphalt layer.The influence of temperature load on the structural performance of conductive rubber composite pavement was greater than that of vehicle static load.When the thickness of the composite material was 5mm(the heat transfer layer was1.5mm and the heat-insulating layer was 3.5mm),it could ensure both the mechanical properties of the bridge deck pavement structure and its heat-producing properties.(4)Design and operation optimization of conductive rubber snow-melting bridge deck pavement.A two-dimensional heat transfer mathematical model of conductive rubber snow-melting bridge deck was established,and its snow-melting mechanism was analyzed.The heat transfer during the snow-melting process of the bridge deck and the calculation and exchange of energy in each part were clarified.Taking saving time(THT)and reducing energy waste(LE)as optimization objectives,particle swarm optimization algorithm was used to optimize the design and operation of conductive rubber heating system.The results showed that under the environment of outdoor average temperature of-3°C and average wind speed of 3m/s,the input power was 300W/m~2,the laying spacing was 20cm,and the conductive rubber composite bridge deck pavement melting 2cm compacted snow took a total of 5.5h.In the scheme design of conductive rubber heating system,it was inefficient to adjust the input power to obtain lower THT and loss of energy rate(LER),while it was more effective to adjust the laying spacing to obtain lower THT and LER.(5)Analysis of damage characteristics of conductive rubber snow-melting bridge deck pavement.The damage characteristics of conductive rubber composite bridge deck pavement were studied through indoor tests.The results showed that the conductive rubber was basically not damaged after the high temperature rolling construction of the asphalt layer,and its physical and mechanical properties and heating performance were basically unchanged.The PB-II waterproof bonding layer material had the best bonding effect between the layers of the conductive rubber snowmelt bridge deck pavement structure.The optimum dosage was 1.5kg/m~2,and the interlayer shear strength was 0.584MPa.Temperature fatigue damage was observed in the asphalt mixtures as the number of heat-up-temperature-down cycle tests increased.After 20times of heating-cooling cycle tests,the Marshall stability decreased by 3.03%,the low temperature splitting strength decreased by 3.90%,and the residual stability decreased by 4.41%.(6)Engineering application of conductive rubber active melting ice and snow system.Considering the actual situation of the project,construction cost and other factors,the design scheme and construction technology of the bridge deck pavement of conductive rubber snow melting ramp were determined.An intelligent sensing active deicing control system was developed,and an automatic start-stop control method of the conductive rubber heating system was proposed based on the temperature distribution characteristics of the bridge deck surface.The results showed that under the condition that the ambient temperature was-4°C,the ambient wind speed was0.6m/s,and the snow thickness of bridge deck was 5mm,the snow-free ratio of bridge deck was greater than 0.5 after 2.5h of heating by conductive rubber heating system,which could meet the normal traffic operation.The installation cost of the conductive rubber active snow melting system was 266 yuan/m~2,and the snow melting cost was about 0.54 yuan/m~2,which had better technical advantages as well as economic advantages compared with the existing electric heating deicing technology. |
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