| Rubber asphalt is a kind of polymer modified asphalt with excellent performance,but in the process of production,mixing and construction,it will produce malodorous smoke that pollutes the environment,which will harm the physical and mental health of construction workers and surrounding residents.At present,the main measures to reduce the emission of rubber asphalt smoke are to add absorbent or reduce the temperature of construction mixing.Based on this,this paper analyzes the composition of rubber asphalt flue gas by means of test,puts forward the main influencing factors of odor,and evaluates the deodorant’s net effect.In addition,the microstructure and chemical characteristics of rubber powder and rubber asphalt were analyzed based on the microscopic test method,and the influence of deodorant molecules on the components of rubber asphalt was explored in combination with molecular dynamics simulation,so as to reveal the clean taste mechanism of rubber asphalt.Firstly,the flue gas generation and concentration devices are designed for the physical and chemical properties of asphalt flue gas.Based on the chemical test method to test the main components of asphalt flue gas,the main pollutants in rubber asphalt flue gas are analyzed by using the chemical substances database,and the asphalt flue gas evaluation method and evaluation index are proposed.Combined with chromatographymass spectrometry(GMS)and electrochemical sensing technology,the effect of deodorant content on rubber asphalt flue gas was studied.The result shows that there are solid particles,liquid particles and gaseous substances in rubber asphalt flue gas,including organic pollutants and inorganic pollutants,and the ones with foul odor are sulfur-containing organic compounds and hydrogen sulfide,such as benzothiazole,methylthiophene,cyclohexanthiol,etc.After the addition of deodorant,the concentration of sulfur content in the flue gas of clean bitumen is greatly reduced,and with the increase of the content of deodorant,the net odor effect of deodorant is gradually enhanced,while the performance of bitumen is basically not affected.Secondly,based on the modern microscopic test method to explore the rubber asphalt clean taste mechanism.By testing the proportion of rubber asphalt elements,the element composition of flue gas is calculated by subtraction method.For analysis of rubber powder in asphalt degradation degree and nature of change,extraction of asphalt rubber powder and content of insoluble particles was calculated by fluorescence microscopy,scanning electron microscopy,infrared spectroscopy,gel chromatography analysis methods such as rubber powder and microscopic structure and chemical properties of rubber asphalt,based on the chromatography mass spectrometry with spectral method in the test of asphalt chemical composition change,based on theoretical analysis,the main components of the deodorant net flavour of rubber asphalt mechanism.The result shows that the content of carbon and sulfur in the flue gas of pure bitumen is less than that of rubber bitumen,and the main pollution elements are still in rubber bitumen.The proportion of non-degraded rubber powder in the clean flavor asphalt is higher,and the molecular weight is smaller.Both deodorants can accumulate rubber powder in the asphalt.Reducing the degree of degradation of rubber powder in the asphalt is the main deodorant’s clean flavor mechanism.Based on mass spectrometry and spectrometric test,it was found that there was no new component with mutated content in the clean bitumen and no obvious chemical reaction occurred in the deodorant.The main components of deodorant were determined by chromatography-mass spectrometry,and the adsorption of deodorant on flue gas was put forward as a secondary mechanism by lewis acid-base reaction and chemical catalytic reaction theory.Finally,the molecular models of petroleum asphalt,rubber powder and deodorant are established by using molecular dynamics software.Mechanical parameters of forcite module analysis model were used to explore the influence of deodorant on rubber powder and petroleum asphalt.The result shows that the molecular model of each material conforms to the element ratio of the material,and the energy of the system reaches a stable state after being optimized by dynamics.It can be seen from the intermolecular interaction that rubber powder and deodorant have stronger interaction ability and are more likely to attract each other at the molecular level,which is consistent with the observation results of fluorescence microscopy and scanning electron microscopy.By testing the radial distribution function of rubber powder and the diffusion coefficient of four components of asphalt,it was found that deodorant can slow down the interaction between asphalt and rubber powder.Thus,the swelling and dissolution of rubber powder in asphalt is inhibited,which proves that the deodorant reduces the volatilization of odorous smoke by reducing the degradation degree of rubber powder.Finally,a pure bitumen with theoretical support and practical application is obtained. |
