Performance of Rigid Pavements Containing Recycled Concrete Aggregate

Abstract

A 1994 field survey was undertaken of pavements containing recycled concrete aggregate (RCA) constructed in Connecticut, Kansas, Minnesota, Wisconsin, and Wyoming. These pavements were resurveyed during the summer of 2006 to update their performance after they had been subjected to 12 more years of traffic. Additional pavements made with RCA from Illinois and Iowa were also observed in 2006. Although the recycled pavements contain higher mortar contents, there was no clear correlation between the higher total mortar content of RCA concrete pavements and cracking distresses in either survey, although one RCA concrete pavement did exhibit more cracking than the control pavement. Overall there was little difference between the 1994 and 2006 surveys. Several pavements were rehabilitated by the addition of dowels for load transfer. These pavements are performing exceptionally well and show that rehabilitation techniques normally applied to conventional concrete work effectively on recycled pavements. Laboratory evaluation of field cores showed that 10 of the 16 pavements surveyed exhibited evidence of alkali–silica reactivity. Eight of these pavements were shown to have significant remaining expansion potential and are expected to continue expanding. All pavements constructed with RCA from concrete showing alkali–silica reactivity and D-cracking exhibited field performance equivalent to their controls and pavements without distress. The recycled pavements have generally performed comparably with their controls. For instance, the present serviceability rating was found to be similar for the recycled and control sections.