A 1994 field survey of pavements containing recycled concrete aggregates (RCA) constructed in Connecticut, Kansas, Minnesota, Wisconsin and Wyomingwas undertaken. These pavements were resurveyed during the summer of 2006 to update their performance after being subjected to 12 more traffic years. 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 recycled pavements higher total mortar content with cracking distresses in either survey, although onerecycled 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 adding dowels for load transfer. These pavements are performing exceptionally well showing rehabilitation techniques normally applied to conventional concrete works effectively on recycled pavements. Laboratory evaluation of field cores showed 10 of the 16 pavements surveyed were found to have alkali silica reaction (ASR), possiblyexplaining why they were originally recycled. Eight of these pavements were shown to have significant remaining expansion potential and are expected to continue expanding. All pavements identified with ASR and D-Cracking showed field performance equivalent to their controls and pavements without distress. The recycled pavements have performed comparably with their controls. For instance, present serviceability rating (PSR) 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.
Samenvatting