Quality Assessment of Mechanical Re-texturing of Road Surface Aggregates

Restoration of a rough texture to a smooth road surface was widely achieved by means of surface treatment. Soon after the Second World War was over, increased interest over the past twenty years in surface treatment by mechanical re-texturing has resulted in the fact that many companies make investments in manufacturing and developing re-texturing machines to operate on the roads and other paved areas. It should be emphasized that there is no need for structural maintenance by the time a road surface becomes slippery. Re-texturing offers the potential for economically increasing a pavement's surface life without the addition of new material. Surface re-texturing of heavy traffic roads often and potentially offers the means of cost effective maintaining adequate resistance to skidding. There are about 14 different ways of mechanical treatment methods among which many of them are based on bush hammering and sand blasting techniques. There is no justification yet on the way one method is more effective than others and why one method is preferred. To overcome this problem, a laboratory apparatus has been designed and a methodology of its operation has been developed by the author of this paper. The apparatus is of a simple design consisting of a table to the side of which the BS 812 road wheel is mounted, exposing one specimen at a time for the use of pendulum for PSV determination, and also for the use of the needle gun and shot blasting treatments.Effective parameters affecting the quality of the end product of the two types of re-texturing treatment i.e. simulated Bush Hammering and Sand Blasting has been evaluated and compared. Robustness of treated aggregate has been examined using thin sections through aggregate and analysis by optical microscope and surface roughness has been assessed using scanning electron microscope.When some aggregates have undergone re-texturing treatments it has been found that some of them end up with significantly higher performance in terms of their re-textured pendulum value, durability of the surface re-textured and its polished stone value (PSV), compared to others. A survey has been carried out in order to determine appropriate methods to retexture samples under laboratory conditions, also find the most suitable ways of aggregates being re-textured and giving enhanced subsequent performance. Parameters affecting the quality of the produced end product of the two types of re-texturing treatment i.e. simulated Bush Hammering and Sand have been evaluated. Robustness of treated aggregates has been examined using thin sections through aggregate and analysis by optical microscope and surface roughness has been assessed using scanning electron microscope.