Maintenance Solutions for Bleeding and Flushed Pavements Surfaced with Seal Coat or Surface Treatment
This report summarizes the findings of research directed at identifying maintenance solutions for bleeding and flushed asphalt pavements surfaced with seal coats or surface treatments. Although the basic mechanism associated with both bleeding and flushing has to do with excess asphalt binder filling the voids between aggregate particles, the terms are different ― "flushed" is past tense; whereas, "bleeding" is an active verb. Factors that contribute to bleeding and flushed pavements include aggregate issues, binder issues, traffic issues, environmental issues, and construction issues. There is no better advice for dealing with bleeding and flushed pavements than to avoid the problem from the outset. Bleeding is an immediate maintenance problem that must be addressed using corrective or in some cases, emergency, maintenance. The basic approaches used to treat bleeding either (a) bridge over the liquid asphalt by applying aggregate of various types and gradations, (b) cool off the pavement surface by applying water with or without additives, or (c) remove the bleeding asphalt and rebuild the pavement seal. Flushed asphalt pavement, in contrast to bleeding, is typically not a maintenance problem that must be addressed immediately. The basic approaches used to treat flushed pavements either (a) retexture the existing flushed pavement surface or (b) add a new textured surface over the flushed pavement. Our research suggests that the use of polymer modified and other binders has improved seal coat and surface treatment performance such that bleeding and flushing problems are becoming less common. Three promising areas for further research and implementation relative to bleeding/flushing solutions include (a) use of lime water, (b) ultra high pressure water cutting, and (c) use of the rackedin seal at intersections.
Project PI: William D. Lawson
Project Co-PI's: Sanjaya Senadheera
Project Researcher: Michael Leaverton
Research Associate: Timothy Wood
Research Assistant: Roderick Henderson