An Introduction to Recycling of Concrete Pavement for Professional Engineers: 49

Concrete pavement recycling is a rehabilitation technique that reuses PCC material in an existing concrete pavement structure. Accomplish the reuse through fractured slab technologies including break/crack-and-seat and rubblization. Alternatively, conduct slab demolition, removal, and reprocessing activities to produce RCA. Depending on the technique, the recycled material can serve as a base material or as aggregate in new PCC or lean concrete base. Recycle composite pavements, where HMA overlays PCC, by first milling off the existing HMA. Concrete recycling offers significant savings in the cost of hauling and disposing of old concrete and it saves natural resources and reduces or eliminates the need for new virgin aggregates. In addition, compared to the conventional form of PCC rehabilitation, HMA overlay directly over existing PCC, recycling can provide substantial performance benefits in terms of alleviating or eliminating reflection cracking in the HMA surfacing. Concrete recycling techniques are mostly suitable for existing pavement with substantially reduced structural capacity. Other forms of rehabilitation better serve pavements with functional distresses or limited structural distress such as concrete pavement restoration (CPR) and HMA or bonded PCC overlays. This discyssion presents detailed information and guidance on the four basic forms of concrete recycling: (1) break-and-seat, (2) crack-and-seat, (3) rubblization, and (4) central plant recycling. Following an overview of the applications of each method, topic sections cover structural and mix design considerations, construction details, and QC/QA issues.