Experimental Study On Photocatalytic Micro-surfacing Mixture With Glass For Degrading Automobile Exhaust

In recent years,in order to solve the increasingly serious air pollution problem caused by automobile exhaust emissions,photocatalytic technology is gradually becoming a research hotspot in the field of road engineering.However,due to poor light transmittance of pavement materials,the application of this technology on micro-surfacing mixture,which used in the road surface pre-maintenance project,is not ideal.In this paper,an appropriate amount of glass particles are used as aggregates and mixed with nano-TiO2 in the micro-surfacing mixture to develop an environment-friendly new material,that is,the photocatalytic glass micro-surfacing mixture,which uses the light transmittance of the glass to introduce Ultraviolet light into the mixture,so as to effectively improve degradation effect of the exhaust gas under the premise of ensuring the road performance,and construction workability,road performance,immediate and long-term exhaust gas degradation efficiency of the mixture under different influencing factors were researched.First of all,the raw materials were screened.Based on the selection of the gradation type and the order of addition,the construction workability of the photocatalytic glass micro-surfacing mixture were analyzed through the mixing test and the cohesion test,and the preparation scheme of the mixture was put forward.The results show that the glass particles meet the basic requirements of light-transmitting aggregates,but are not suitable as coarse aggregates to assume the skeleton function of micro-surfacing mixture,and the mixing of appropriate amounts of cement can provide the mixture a better construction workability and early strength.Then,starting from influencing factors such as glass contents,particle size composition of glass,nano-TiO2 contents and asphalt contents,a four-factor and three-level multi-index orthogonal experiment was designed to carry out range analysis of abrasion resistance,anti-skid,water stability,anti-rutting and other roads performance,also with degradation efficiency of exhaust gas,through comprehensive balance method and experimental verification,the optimal blending plan of the photocatalytic glass micro-surfacing mixture was proposed.The results show that the road performance of photocatalytic glass micro-surfacing mixture gradually declined with the increase of the glass contents.However,under the premise of meeting the current specifications and technical requirements,when a suitable content and particle size of glasses are added,it can greatly improve the instant degradation efficiency of the photocatalytic micro-surfacing mixtureFinally,the actual service conditions of the photocatalytic pavement were investigated,and long-term degradation efficiency test schemes of the photocatalytic pavement materials based on tire abrasion and repeated degradation were designed to simulate the scene where the photocatalytic glass micro-surfacing mixture was affected by some road factors.The long-term degradation efficiency of the material under the conditions of tire abrasion,repeated degradation and water washing has been studied,and compared with the photocatalytic fog seal layer.And on this basis,the application of photocatalytic pavement is proposed.The results show that although the instant degradation efficiency on automobile exhaust of the photocatalytic glass micro-surfacing mixture is slightly lower than that of the photocatalytic fog seal,its long-term degradation efficiency is significantly better than that of the photocatalytic fog seal under repeated wheel wear.As the number of repeated degradation increases,effective degradation rate of the photocatalytic glass micro-surfacing mixture is gradually reduced,due to the accumulation of photocatalytic by-products on the surface,but the high-pressure water gun flushing method and a reasonable flushing cycle can restore the degradation function of mixture to the maximum extent,so as to give full play to its long-term degradation efficiency.The research results can not only improve the degradation efficiency of vehicle exhaust of photocatalytic micro-surfacing road effectively,alleviate air pollution,and improve the ecological environment,but also help expand the resource utilization approach of waste glass and reduce the use of sand and gravel materials.And they play a significant role in the building of a resource-saving and environment-friendly society.