Use of Micro-Surfacing in Highway Pavements (1289-2F)

Micro-surfacing is a complex mixture of polymer modified emulsified asphalt cement, crushed mineral aggregate, mineral filler, water, and other additives. When designed and constructed properly, micro-surfacing can be used in thin layers as preventive maintenance and in thick layers to fill ruts as corrective maintenance treatments. Several Districts are using micro-surfacing to repair pavement in the Texas Department of Transportation. The contractor provides the mixture design, and the Department accepts the mixture. The mixture designs submitted by the contractors are based on tests that the Department has not previously used and that have questionable validity.|This project developed specifications, mixture design procedures, mixture design verification procedures, usage guidelines, and quality assurance requirements for micro-surfacing treatments applied to highway pavements. The mixture design procedure tests were evaluated in the laboratory and modified as needed. Detailed protocols were developed for each test. Micro-surfacing mixture designs and quality assurance procedures were tested in the field. Quality assurance checklists were developed for use by field personnel. This report presents a method for evaluating cost-effectiveness along with preliminary results. An approach for completing forensic analysis of early failures was also prepared.