Experimental Study On Automobile Exhaust Degraded By Photocatalytic Asphalt Mixture With Waste Glass

In recent years,in order to solve the increasingly serious problem of automobile exhaust pollution,the photocatalytic ecological pavement which can degrade automobile exhaust is becoming a research hotspot in the field of roads.The present application of photocatalytic technology on asphalt pavement,which accounts for the vast majority of urban roads,is not ideal.The literature shows that the significant improvement in exhaust degradation efficiency can be achieved by adding an appropriate amount of glass beads as aggregate to the photocatalytic asphalt mixture,but the road performance of the mixture has declined.Therefore,based on the analysis of the technical performance of waste glass particles,waste glass particles of different sizes and shapes were blended into the photocatalytic asphalt mixture in order to study the road performance and the effect of degrading automobile exhaust under various pollution conditions.First of all,the source of waste glass was investigated,and three kinds of waste glass granules were selected to study their particle size range,appearance characteristics,physical properties,mechanical properties and adhesion with asphalt.The results show that the compressive resistance of waste glass and its adhesion with asphalt are lower than those of lineral aggregates commonly used for road engineering,but SBS modified asphalt can significantly improve the adhesiveness.Secondly,the mixing ratios of two gradation photocatalytic asphalt mixtures with waste glass particles of different sizes and shapes were designed,and the optimal asphalt contents were determined.The Marshall indicators under the optimal asphalt content conditions were tested.The results show that the AC-13C photocatalytic asphalt mixture added by waste glass particles with angular edges of larger size demonstrates better Marshall stability.And then,through rutting test,low-temperature bending test,immersion Marshall test,freeze-thaw splitting test,sand patch test and automobile exhaust degradation test,the road performance and degradation capability of two gradation photocatalytic asphalt mixtures with waste glass particles of different sizes and shapes were tested and analyzed.The suitable particle size range and shape requirements of waste glass are proposed.The results show that high-temperature stability and water stability of the photocatalytic asphalt mixture with waste glass particles of larger size are better.But the size of waste glass has little effect on low-temperature cracking resistance and anti-sliding characteristics of the mixture.The road performance of the photocatalytic asphalt mixture with broken glass particles is better than that of the mixture with glass beads of the same particle size,but the latter has a slightly better degradation effect on automobile exhaust..Compared to SMA-13 gradation,the photocatalytic asphalt mixture with broken glass particles of the diameter from 2.36 to 4.75 millimeters is more suitable for using AC-13C gradation.On the basis of considering the natural degradation of NO and other gases in the air and the loss of exhaust gas concentration by the automobile exhaust gas analyzer,combined with the characteristics of the hybrid input of automobile exhaust,a new evaluation index of the degradation of automobile exhaust gas by photocatalytic materials is proposedFinally,three pavement pollutants such as dirt,oil stain and snow-melting salt were selected,and automobile exhaust degradation tests of photocatalytic asphalt mixture samples with different contamination degrees were carried out.Meanwhile,the impact of water flushing were analyzed.The results show that dirt,oil stain,and snow-melting salt contamination could decrease the degradation efficiency of the mixture to the vehicle exhaust.The higher the contamination degree is,the lower degradation efficiency is.But the degradation efficiency can get a greater degree of recovery after water flushing.It is recommended to clean up the pollutants on the photocatalytic pavement on a daily basisThe research results will provide technical support for the further popularization of photocatalytic asphalt pavement,and then contribute to the improvement of China's ecological environment and the construction of a resource-saving and environment-friendly society.