Preparation And Application Of Asphalt Cement With Automobile Exhaust Photocatalytic-purification Efficiency

In recent years,the number of automobile ownership has been increasing,and the environmental pollution caused by automobile exhaust has become increasingly serious,so how to carry out green development has become the focus of research.In this context,the use of photocatalytic technology to degrade the exhaust gas at the surface of the load road has become a research hotspot in road engineering.Although TiO₂ has a certain effect on the degradation of nitrogen oxides,the degradation efficiency of traditional TiO₂ photocatalytic materials is not high,only about 50%,and the reaction products may also cause secondary pollution of the environment,so some modifications to TiO₂ need to be made.In this paper,hydrotalcite（LDHs）was modified in combination with TiO₂,and its properties after adding asphalt were studied.In this paper,TiO₂@LDO composite photocatalytic materials were first prepared,the photocatalytic and adsorption efficiency of asphalt cement with photocatalytic efficiency was tested macroscopically,and the molecular characteristics and apparent morphology analysis were carried out by FTIR and AFM at the microscopic level,and the optimal photocatalyst content of asphalt cement was comprehensively determined.Secondly,on this basis,the asphalt slurry with photocatalytic efficiency was studied through three aspects:basic properties,adhesion properties and rheological properties,and the optimal powder ratio of asphalt slurry was determined.Finally,based on the above research,the purification efficiency of asphalt cement,asphalt slurry and asphalt mixture with photocatalytic efficiency was explored,and the interaction between TiO₂@LDO and asphalt was studied through Materials Studio（MS）molecular dynamics simulation to further reveal the mechanism of action,and finally its economic benefits were analyzed.The main research contents and conclusions of this paper are as follows:（1）Based on theoretical research,TiO₂@LDO composite photocatalytic materials were prepared,and the photocatalytic efficiency and adsorption efficiency of asphalt cement after adding photocatalytic material TiO₂ and TiO₂@LDO were evaluated at the macroscopic level,and it was found that the photocatalytic efficiency of the cement was positively correlated with the irradiation intensity,and only the TiO₂@LDO asphalt cement had adsorption effect.Under the same conditions,6%TiO₂@LDO asphalt cement has the highest photocatalytic efficiency and the best adsorption efficiency,and the photocatalytic efficiency of asphalt cement with this ratio can reach up to 53.27%,and the adsorption rate of asphalt cement with 6% TiO₂@LDO can reach 38.4% in four days of testing.From the microscopic level,it is found that the interaction between photocatalytic materials TiO₂ or TiO₂@LDO and bitumen is mainly caused by physical adsorption,and TiO₂@LDO can show stronger adsorption with polar components in asphalt.（2）Based on the obtained optimal ratio of asphalt cement to prepare asphalt slurry with different powder to rubber ratio,the conventional performance found that with the increase of powder to rubber ratio,the softening point of asphalt slurry increased,the adhesion increased,but the ductility and penetration decreased,and when the powder to rubber ratio was 1.0,the high temperature and low temperature were improved.At the same time,the rheological properties test was carried out by DSR,and it was found that the powder rubber ratio had a great influence on the complex shear modulus *,the elastic storage modulus′and the viscous loss modulus ′′at low temperatures,and the high temperature rutting resistance and fatigue cracking resistance of the glue could be effectively increased at lower temperatures.When the powder-to-rubber ratio increases,the ′and ′′of asphalt slurry can be increased accordingly,and the ability of asphalt glue to resist rutting at high temperature can be increased,and the change is obvious when the powder-glue ratio is 1.0.In summary,it can be found that the asphalt slurry with a powder-to-rubber ratio of 1.0 when the photocatalytic material is 6% TiO₂@LDO is the optimal ratio.（3）Based on the determination of the optimal ratio of asphalt cement and asphalt slurry,the nitrogen oxide purification efficiency test of asphalt cement with bitumen slurry and asphalt mixture with photocatalytic purification efficiency was carried out,and it was found that the NO degradation rate of asphalt cement,asphalt slurry and asphalt mixture was affected by light and temperature,and was more sensitive to light.At the test temperature of25 °C and the height of the test set at a height of 15 cm from the light,the degradation rate of asphalt cement and asphalt slurry was 19.8% and 26.9%,respectively.The degradation rate of NO by internal doping method and powder coating method can reach 40.0% and78.6%,respectively.Through MS,the mechanism analysis of TiO₂@LDO bitumen cement was carried out,and it was found that with the increase of the simulated temperature,the greater the diffusion coefficient of the TiO₂@LDO,the higher the high temperature performance can be improved,and the adsorption between asphalt and TiO₂@LDO is the strongest and the bonding strength is the largest at a temperature of 40 °C,which can indicate that the purification efficiency is affected by temperature.Finally,the economic benefits found TiO₂@LDO the environmental benefits of asphalt pavement are much higher than the construction costs.