A survey of the 50 state highway departments on their use of blade-patching as a maintenance technique is summarized. Blade-patchingis defined as cleaning a pavement area, applying tack coat, applying asphalt mix with a motor grader or spreader box, and compacting. On the basis of the information obtained from the survey, a cost analysis comparing blade-patching to a 2-in overlay was made, illustrating the use of an economic model for decisions between maintenance alternatives. Of the 43 states that responded to the survey, 38 use blade-patching. State highway divisions spend more than $175 million ayear on blade-patching, but there is wide disagreement about its usefulness. The best estimate of blade-patch life is 3 years, and economic analysis comparing blade-patching to a 2-in hot-mix overlay indicates that blade-patching should seldom be used if traffic exceeds 1, 500 average daily traffic or if blade-patching required to maintain the pavement exceeds 125 ton/mi/year.
Abstract