Rubblization of Airfield Pavements: State of the Practice

With the airlines reporting passenger numbers returning to pre-September 11, 2001, levels, demand for more aircraft operations at the nation's airports is continuing to grow. This growth will continue to stress the nation's older concrete airport pavement infrastructure that has already served beyond its design and service limits for which it was constructed. As a result, a major portion of these concrete airport pavements will require rehabilitation in the very near future. Traditionally, concrete pavement restoration (CPR) procedures have been employed to maintain these pavements in a fair to good condition. With growing demand and rapidly aging pavements, these CPR procedures are becoming more costly and less effective as the present pavement condition ratings are reaching a critical point where major rehabilitation is required. Rubblization and repaving with hot-mix asphalt (HMA) is quickly becoming the portland cement concrete (PCC) pavement rehabilitation technique of choice for old deteriorated PCC airfields. In the past 7 years, well over one-half million square meters of PCC have been rubblized in place, resulting in a stiff unbound granular base layer for new HMA pavements. With the Federal Aviation Administration's (FAA's) recently published guidance and specification for rubblizing airfield PCC, the use of rubblization should continue to grow on both civilian and military airfields. The same benefits that highway agencies realize with rubblization are now being recognized by airfield agencies. This is vital as our airfield pavement infrastructure, much of which is PCC pavement, continues to age beyond the point of restoration. This paper presents the concepts associated with the process of rubblization, equipment development, specification criteria and in-service performance for rubblizing airfield pavements. The focus of this paper is the application of rubblization technology to airfields, designed for both light loads and heavy loads. Discussion items include: rubblization process; characteristics of state-of-the-practice equipment for rubblizing airfields; specifications for rubblizing airfield pavements, including recent FAA guidance; recent projects that demonstrate the ability to successfully rubblize heavy load airfield concrete pavement up to 26 in. thick; recent and upcoming rubblization projects on airfields in the United States; and design/construction issues unique to airfields.