The Research On Reparation And Properties Of Light Screening Preventive Maintenance Agent At Asphalt Pavement In Tibet Plateau Area

Asphalt pavement is vulnerable to the combination of factors such as increscent trafficincrease, growing size of vehicles, serious overloading, channel traffic as well asenvironmental effects like sunshine intensity and water, which will cause various earlydamages like cracks, ruts, loose surface, spalling, pits and impact the performance of thehighway; as a result, asphalt pavement necessarily needs maintenance and repairing. As themileage of asphalt pavement skyrockets and the service time of highway prolongs in China, itrequires huge amount of efforts to maintain them. Preventive maintenance is a kind ofmaintenance method which prevents the development of damage proactively even beforedamage to the surface occurs, it has advantages of early maintenance and low cost. Due tohigh altitude, great day-night temperature difference, long sunshine duration, thin air andstrong ultraviolet radiation, Tibet Plateau area is not only more vulnerable to above damages,but also exposed to photooxidation aging damages like road surface discoloration. Therefore,preventive maintenance becomes very importance for this area due to the specialenvironmental conditions.Considering the special climate conditions and the lack of application of preventivemaintenance technology in Tibet Plateau area, the light screening preventive maintenanceagent was developed based on the current preventive maintenance technology and asphaltaging mechanism and recycling principle, and experimental analyses of its constituentmaterial, constituent quantity, preparation and property were conducted. It was concluded thatthe light screening preventive maintenance agent consists of high-grade petroleum asphalt,organic recycling agent, bonding curing agent, osmotic agent and light screening agent withadvised quantity of20%-40%,20%-30%,30%-40%,15%-20%and3%-5%respectively.The indoor aging experiment under strong ultraviolet and bonding curing experimentshows that light screening preventive maintenance agent has three effects. First, it canpenetrate into asphalt layer to activate and restore the original property of aging asphalt; as aresult, old and new asphalt can merge together and the regenerated old asphalt can reach thestandard of original asphalt. Second, it can not only improve the adhesive strength of asphaltand aggregate and wrap the loose and peeling off aggregate, but also supply asphalt binder for aging and peeling off, seal micro-cracks on pavement and form a new protective surface toprevent water penetration. Last, it can screen ultraviolet radiation and improve the appearanceof pavement by restoring its color, so that the contrast of asphalt pavement and traffic lineswill be increased. The article proposes new ideas and methods to delay the aging process ofnewly constructed asphalt pavement and regenerate old asphalt pavement.