Validation of New Mix Design Procedure for Cold In-Place Recycling with Foamed Asphalt

Abstract

The main objective of this study is to validate a new mix design procedure for cold in-place recycling using foamed asphalt (CIR-foam) developed for the Iowa Department of Transportation. First, reclaimed asphalt pavement (RAP) materials were collected from seven different CIR construction sites located across the state of Iowa. To determine the consistency of a new CIR-foam mix design procedure, the mix design was performed seven times using these RAP materials. The test specimens were prepared using gyratory compactor rather than Marshall hammer because it produced more consistent mixtures for various foamed asphalt contents and curing conditions. The indirect tensile strength test was performed on the vacuum-saturated specimens prepared using each of seven RAP material sources for five different foamed asphalt contents (1.0, 1.5, 2.0, 2.5, and 3.0%), given a fixed moisture content of 4.0%. As the foamed asphalt content increased from 1.0 to 3.0% at 0.5% increments, air voids in the CIR-foam mixtures decreased gradually. The indirect tensile strength of CIR-foam specimens cured for two days at