01045152

Component

During the conduct of a nine-site field investigation in 1994, it was found that five separate State Highway Agencies (Connecticut, Kansas, Minnesota, Wisconsin and Wyoming) had successfully designed and constructed rigid pavements containing recycled concrete aggregates (RCA). The positive results were attributed, in part, to the minimization of old mortar content in the RCA during recycling processes and/or being able to achieve higher than expected compressive strengths through adjustments in mix proportions. These pavements were resurveyed during the summer of 2006 so as to determine their performance after being subjected to significant traffic. Although the recycled pavements typically contain higher mortar contents, there was no clear correlation between mortar content and cracking distresses in the field investigation during both surveys, although one project did exhibit significantly more slab cracking in the recycled pavement than in the corresponding control pavement (88 percent versus 22 percent, respectively) in 1994 there was little difference in 2006 (92 percent versus 24 percent respectively). The initial cracking may have been due to the large differences in total mortar content between the recycled and control sections (83.6 percent versus 51.5 percent, respectively). Several sections originally evaluated in 1994 were rehabilitated by adding dowels for load transfer. These pavements are performing extremely well showing that rehabilitation techniques normally applied to conventional concrete works effectively on recycled pavements as well. In general, the recycled PCC pavements considered in this study have performed comparably with their conventional PCC pavement counterparts. For instance, decrease of the present serviceability rating (PSR) with time was found to be similar for the recycled and control sections. Likewise the recycled pavements that incorporated RCA derived from D-cracked and alkali-silica reactive (ASR) concrete appears to be performing at least equivalent to the original pavements. There is, however, evidence of surface cracking suggesting recurrent ASR activity in the recycled Wyoming pavement.

01042056

07-2907

English

24p

2007

Transportation Research Board 86th Annual Meeting

CD-ROM

Photos (3) ; References (9) ; Tables (7)

Alkali; Alkali silica reactions; Cracking; Cracking of asphalt concrete pavements; Fracture mechanics; Mixtures; Mortar; Pavement design; Pavement distress; Pavement performance; Pavements; Portland cement concrete; Recycled materials; Rigid pavements

Recycled concrete aggregate; Surface cracking

Design; Highways; Materials; Pavements; I22: Design of Pavements, Railways and Guideways; I32: Concrete

Transportation Research Board Annual Meeting 2007 Paper #07-2907

PRP, TRIS, TRB

Feb 8 2007 7:36PM