Performance of I-57 Recycled Concrete Pavement

摘要

In 1986-1987 the Illinois Department of Transportation (IDOT) constructed a demonstration project on I-57 near Effingham, Illinois, to evaluate the viability of recycling an existing jointed reinforced concrete pavement for use as its primary aggregates in the surface mixture of a 10-in continuously reinforced concrete pavement (CRCP). This CRCP test section on northbound and southbound I-57 contained a 7-in cement-stabilized subbase and a 13.5-ft extended lane width. Longitudinal reinforcement bars were placed using the tube feeding method. Functional and structural data, including falling weight deflectometer testing (FWD), distress surveys, friction testing, surface profile testing, and conditions rating surveys were collected periodically throughout the life of the pavement. Structural test data demonstrates a pavement section that has exhibited excellent load carrying capacity (less than 0.006-in deflection under 9-kip load), and load transfer efficiency across the transverse cracks. Furthermore, the cement-treated subbase and subgrade have performed well over the CRCPs service life. There also was no structural response or cracking difference between the sections with the stabilized base extended under the shoulder versus the base that is only a standard lane width. Few structural distresses are observed except for the prominent amount of longitudinal cracking that appears over the reinforcement bars in all lanes. This abnormal cracking pattern has been noted for many years and has been attributed to settlement cracking associated with the original tube feeding process, the bar size selected, the bulk density of the concrete with recycled concrete aggregate (RCA), and the higher drying shrinkage of RCA concrete. The section has developed a significant amount of localized distresses and patches over the past 5 years as a result of the further deterioration of this longitudinal cracking distress.