Mechanistic Design and Nondestructive Structural Validation of a “Green Street” Test Section Using Recycled Rubble Materials

The City of Saskatoon, Saskatchewan, Canada, commissioned the “Green Street” Infrastructure Program to investigate the potential of using recycled reclaimed asphalt pavement (RAP) and portland cement concrete (PCC) rubble as structural road layers. This study validated the mechanistic materials characterization and structural design of a field test section constructed using recycled RAP and PCC materials in addition to in situ reclaimed and recycled road materials. This paper presents a summary case study of the Green Street test section on 8th Street in Saskatoon. The rehabilitation of 8th Street consisted of two pavement rehabilitation systems: one incorporated a drainage layer and the other did not. The rehabilitation of the right-turn lane included a drainage system incorporating City of Saskatoon offsite impact-crushed PCC rubble material. The entire right-hand-turn lane and sections of the median lane and the driving lane were rehabilitated by rotomixing hot-mix asphalt concrete (HMAC) and granular base layers and adding offsite impact-crushed RAP to top up the remixed base layer. The top 200 mm of this remixed base layer was stabilized with cement–emulsion. The entire 8th Street test section was surfaced with typical City of Saskatoon HMAC. When subjected to mechanistic triaxial frequency sweep characterization, both the cement–emulsion-stabilized in situ remix material (utilized as a black base course) and the HMAC surfacing materials showed good mechanistic structural material constitutive behavior. The stabilized in situ remix material yielded end-product mechanistic material behavior that exceeded that of the HMAC surfacing.