CC2 HMA Overlay Test Objective
Rubblization is a method of in situ recycling of deteriorated concrete pavements. The rubblized layer behaves as a tightly keyed, interlocked, high-density unbound base. FAA published guidelines for rubblized Portland cement concrete base courses are summarized in Engineering Brief (EB) 66 (FAA, 2004) and are based on broad industry experience. EB 66 is an interim guidance and full-scale testing is still needed to develop design standards for the use of this technology at airports under heavy aircraft loading. As a start, three rigid airport pavement test items (MRC, MRG, and MRS) at the Federal Aviation Administration’s (FAA) National Airport Pavement Test Facility (NAPTF) with 12-inch (30.5 cm) thick concrete slabs on different support systems (slab on crushed stone base, slab on grade, and slab on stabilized base) were rubblized with a resonant pavement breaker and overlaid with five inches of P-401 hot mix asphalt (HMA). The rigid pavements had been trafficked to complete failure prior to rubblization using dual-tandem and triple-dual-tandem landing gear configurations at wheel loads of 55,000 lbs (25 tonnes). All three test items were constructed on clay subgrades of approximately 7 CBR. The overlaid pavements were subjected to full-scale accelerated traffic loading.
- Conduct a study on the full-scale accelerated pavement testing of rubblized concrete pavements with HMA overlay under heavy aircraft loading.
- Observe the changes in the modulus of the rubblized concrete layer with deterioration in pavement structure backcalculated using BAKFAA.
- Pavement layer characterization tests, pavement structure uniformity from HWD tests, and pavement performance during the traffic tests