Validation of mix design procedure for Cold In-Place Recycling with foamed asphalt

Abstract

As Cold-In-place Recycling (CIR) continues to evolve, in order to place the CIR mixture with specific engineering properties, the use of a mix design process is required. In this study, to improve the consistency of the CIR using foamed asphalt (CIR-foam) mix design process, the critical mix design parameters were identified and the laboratory test procedure was modified. To determine optimum foamed asphalt content, the indirect tensile strength test is recommended to be performed on vacuum-saturated and gyratory-compacted CIR-foam mixes. To determine its consistency over the wide range of RAP materials, the CIR-foam mix design process based on the indirect tensile test was validated against seven different RAP sources collected across the state of Iowa. Based on the developed mix design procedure, the optimum foamed asphalt contents were consistently found at values between 1.5 % and 2.5 % for seven different RAP materials.