Study On The Application Technologies Of Fog Seal For Asphalt Pavement

As a preventive maintenance technology, Fog seal has been widely used inforeign countries while less in domestic highway. The study for material performanceindex and test methods is few, and there is no systematic regulatory requirements forconstruction technology and quality control. Based on indoor experimental study andphysical engineering verification, this paper is concentrated on the materialperformance index and test methods for fog seal with regenerative function,developing a new type of fog seal product EFS and forming the Fog seal ConstructionTechnology Guide suitable for Chinese situation, the aim is to provide the basis forthe promotion and application of fog seal.Through research in this paper, fog seal is defined as a type of liquid sealinglayer material at normal temperature which is sprayed a little on the road surface inthe form of fog (also be coating method in the small area construction), to form a thinlayer of protective layer in order to protect pavement or recycle the existing asphaltpavement, or a combination of these two functions. Research indicated that Fog sealshould have good properties such as fluidity at normal temperature, adhesion,water-sealing, abrasion-resistance and quick-drying, and it is better to have recyclingagent in Fog seal.Through the indoor contrast test of emulsified asphalt, modified emulsifiedasphalt, recycled asphalt, CAP and ERA-C, the results demonstrated that three Fogseal dedicated sample exhibit excellent performance in different aspects respectively,which is recycled asphalt, CAP and ERA-C. But emulsified asphalt and modifiedemulsified asphalt exhibit poor overall performance. So the choice of materialsdepends on the focus of preventive maintenance requirements by road conditions.Through the follow-up observations of recycled asphalt, CAP and ERA-C in thephysical works, the results demonstrated that one year after Fog seal was used, theissues of slightly loose and water damage in the original pavement was solved and norecurrence of small cracks. Surface consolidation function, sealing water function andfunction to prevent the occurrence of small crack was verified. Fog seal could be basically consistent with the subsided speed of the color of the newly built road,keeping the color basically uniform after revision; Fog seal would reduce theanti-slide performance of the road surface in the initial period, but after a period oftime, or take some measures, the anti-slide performance could meet the regulatoryrequirements.On this basis, a new type of Fog seal products EFS is developed, the indoorexperimental study and physical engineering verification is conducted to study thepavement performance. The results demonstrated that the performance of EFS andERA-C is similar, especially quick-drying, surface consolidation and abrasionresistance is excellent, achieving the research purpose. EFS can improve theperformance of fine sand consolidation, by spreading a small amount of fine sand, thepavement anti-slide performance can be significantly improved. Economic benefitanalysis results showed that compared with micro-surfacing and repair-resurfacing,the cost of EFS is lower calculated by the service life of two years, maintenance costssave77.38%and51.04%, respectively. It has significant economic benefits.