Surface Preparation on the Dan Ryan Expressway Using High-Speed Scarification

摘要

The Dan Ryan Expressway (1-94) reconstruction project, between 13th Street and the 1-57 interchange in Chicago, IL, involved the reconfiguration of ramps and interchanges, installation of enhanced sewers, construction of new lanes, as well as repair of the existing lanes. Part of the process of repairing the existing bridge lanes was to prepare the surface and install a microsilica concrete overlay. The Illinois Department of Transportation (IDOT) required that equipment must be used to remove the weak concrete at the surface, including the microfractured concrete surface layer remaining as a result of mechanical scarification. IDOT further specified minimum tensile bond strengths on the prepared surface of 175 and 150 psi (1.2 and 1.0 MPa) on the bonded overlay. To achieve this requirement, IDOT required mechanical grinding followed by highspeed hydroscarification or simply high-speed scarification (HSS).