| Epoxy asphalt is made of asphalt mixed with epoxy resin,curing agent and other materials at a certain ratio.Because of its excellent physical and mechanical properties,it is widely used in the pavement of steel bridge decks,but most of its related research has focused on epoxy Asphalt preparation,performance and compatibility of epoxy resin and asphalt,the study of epoxy asphalt regeneration has not been involved.Epoxy asphalt recycling technology can not only effectively reduce the use of resources,but also face the high cost,it can also turn waste into treasure,and fully achieve the purpose of saving economy and resource consumption.Therefore,designing a renewable epoxy asphalt is extremely important for the development and sustainable use of epoxy asphalt.Limited to the limitations of experimental research,consider studying the epoxy asphalt curing reaction mechanism and regeneration mechanism from a microscopic molecular perspective.All quantum chemical calculations and molecular dynamics simulations in this thesis are carried out using Materials Studio software.First,the raw material molecules of renewable epoxy asphalt are selected,and the molecular composition of cured epoxy asphalt is analyzed from the principle of chemical reaction.Finally,based on the research results of asphalt aging products,the key parts of the aging molecular structure of renewable epoxy asphalt are inferred.Secondly,molecular dynamics simulation was used to verify the selection of renewable epoxy asphalt molecules.Through the construction and verification of the matrix asphalt molecular dynamics model,it is confirmed that the selected components of the asphalt are reliable and can be used in the next step of the construction of the renewable epoxy asphalt molecular model.Based on the existing molecular dynamics model of epoxy resin curing cross-linking structure,a molecular dynamics model of epoxy asphalt was constructed;the molecular dynamics model of epoxy asphalt material was generated using the selected force field and simulation parameters.It has been verified that the model constructed conforms to the characteristics of epoxy asphalt materials and can basically represent renewable epoxy asphalt materials.All molecules can be applied to the research of the curing mechanism and regeneration mechanism of renewable epoxy asphalt.Then,quantum chemical calculations were used to reveal the curing mechanism of the developed renewable epoxy asphalt.Theoretical research on the mechanism of chemical reaction is to use computational materials science to simulate the process of chemical reaction and find the transition state and energy change of the reaction.According to the general configuration process of epoxy asphalt,as well as the raw materials and the inferred molecular structure,the molecular model of each reactant and reaction product is constructed in the Dmol~3 module,and the structure is optimized.Then,each reactant is matched with the reaction product,and a reaction preview is performed to obtain the transfer of each reaction electron and the breakage and generation of chemical bonds.Finally,a transition state search was performed on each reaction and its finishing treatment was carried out,so that the changes of free energy and activation energy barrier in each reaction were obtained,which provided a theoretical basis for the curing reaction mechanism of regenerated epoxy asphalt.Finally,quantum chemical calculations were used to explain the regeneration mechanism of the designed renewable epoxy asphalt.Theoretically analyzed the aging changes of renewable epoxy asphalt during the regeneration process,and finally found that during the regeneration process of renewable epoxy asphalt imine hydrolysis reaction,resin phase hydrochloric acid reaction,aging asphalt phase concentrated hydrochloric acid reaction,aging asphalt phase reacts with the epoxy group and the reverse reaction of the imine hydrolysis.Then,the quantum chemistry calculation was used to analyze the above reactions,and the changes of free energy and activation energy barrier in each reaction were obtained,which provided a theoretical basis for each reaction mechanism of the epoxy asphalt regeneration.Finally,based on the above analysis,the regeneration mechanism of epoxy asphalt is summarized. |
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