In the Fall of 1991, a research study was initiated to assess the effectiveness of micro-surfacing as a potential pavement surface rehabilitation technique. Micro-surfacing consists of a polymer modified emulsified asphalt binder, aggregate, mineral filler and water, mixed and spread cold in a thin layer on top of an existing pavement surface. It sets quickly (typically about one hour) so that traffic disruption should be minimized. Micro-surfacing is not intended to provide a structural improvement for the roadway but rather to repair pavements with surficial distresses such as coarse aggregate loss and ravelling or to improve pavement surface frictional resistance. The pavement section selected for the micro-surfacing trial had previously been the subject of an only partially successful hot in-place recycling trial. Although the pavement was considered to be structurally sound, the surface had begun to ravel, rut and was generally inconsistent. Prior to micro-surfacing, a detailed pavement surface distress survey identified the severity and density of all of the observable surface distresses, longitudinal profile and cross section measurements and surface texture characterization were completed. A micro-surfacing design was completed in accordance with the procedures suggested by the International Slurry Surfacing Association (ISSA) and the trial section work performed by a specialist contractor in the fall of 1992 with continuous monitoring during construction and at regular intervals since. The previous measurements have been repeated after micro-surfacing as a part of a multi-year monitoring program. The results of the first year of monitoring are presented in this paper. (A)
Abstract