Upcoming Projects

The following are a list of current applied research needs related to concrete pavement airfields. This is only a partial list and is subject to change through discussion with the ACPTP program coordination group and/or technical advisory committee.

ACPTP 2022-5 Best Practices for Concrete Runway Rubber Removal

The object of this effort is to produce a best practices guidance document for the removal of rubber from airport runways. Since the 2008 synthesis on Removal Techniques, the industry approach has evolved to where hydro-blasting has become the primary, although not the only, method that maintenance operations employ for removing rubber from runways.  Although the primary emphasis is on hydro-blast processes, the guidance will also identify and address best practices for other rubber removal processes.

ACPTP- Strength Acceptance Methods for Concrete Pavements

Current standards for pavement acceptance for FAA pavements are based on quality assurance flexural beam testing. Beams are sensitive to various things that can impact their validity. This questionable validity has been the cause of numerous disputes during airfield pavement construction. In 2003 the APTP conducted research looking into using maturity testing for airfield concrete pavement construction and repair. The research showed promise for a new method of pavement acceptance. However, more research must be done to compare the beams and cylinders versus some new, more reliable method of pavement acceptance for strength.

ACPTP- Effects of Diamond Grinding on Airfield Pavements

FAA specifications require a certain level of smoothness for some features such as runways and taxiways. In addition, grade control must be met for pavements to provide safe landing and travel surfaces for aircraft. Tolerances for these requirements can be stringent. Construction issues can sometimes compromise meeting these tolerances and the FAA construction specifications require diamond grinding to bring pavements into compliance with specifications. The FAA also has strict limits on the amount of grinding area that is allowed on projects without penalty. The amount of diamond grinding and these penalties are set arbitrarily. No research exists today to support the technical requirements of grinding contained in specifications. Anecdotal evidence exists where some projects that were diamond ground many years ago are performing as well as, if not better than, pavement placed at the same time with the same materials. Research is needed to determine the effects, if any, of diamond grinding of airfield pavement performance.

ACPTP- Limestone Cements

PLC cements are becoming the norm in many locations, with Type I or Type II cements no longer available. A review is needed to evaluate the potential effects of these changes on airfield specifications and performance.

ACPTP- Load Transfer in Concrete Pavement

Current FAA and Department of Defense standards for airfield pavement are designed for aggregate interlock to provide for load transfer in contraction control joints except for the last three joints at the end of a feature or adjacent to an isolation joint. The thinking is that aggregate interlock will provide for at least the design assumption for load transfer, which is assumed to be 25 percent. However, many engineers question if this assumption is valid during concrete contraction in cold weather or after numerous expansion and contraction cycles. The question remains if the dowels provide increased load transfer efficiency and if they do, does it increase pavement performance enough to justify the increased cost of construction. Applied research is needed to assess the performance and value of dowelled versus un-dowelled contraction joints.

ACPTP- Start/Stop Practices

There are mixed opinions regarding whether it is preferable to start/stop a paving machine or to slow it down if concrete deliveries are insufficient. Guidance is needed to assist contractors and inspectors on how smoothness can be best maintained under varying conditions with regard to materials delivery.