Rational Mix-Design Procedure for Cold In-Place Recycling Asphalt Mixtures and Performance Prediction

Abstract

A new volumetric mix-design procedure utilizing the Superpave gyratory compactor (SGC) was developed for cold in-place recycling (CIR) asphalt mixtures with assistance from the Federal Highway Administration (FHWA). It was developed for partial-depth CIR using asphalt emulsions as the recycling additive. This procedure was calibrated using materials from five geographically varied locations in North America: Connecticut, Kansas, Ontario, Arizona, and New Mexico. It required that specimens be prepared at densities similar to those found in the field. The performance of CIR mixtures prepared in accordance with the new mix-design procedure was evaluated in the laboratory with mechanistic-empirical pavement design guide (MEPDG) models as well as in the field. Creep compliance and strength of the mixtures were determined at 0, −10, and −20°C using the Superpave indirect tensile tester (IDT) with satisfactory results. A field test section also had been established with CIR mixtures in Arizona using this procedure and has been performing well with no significant visible cracking or distresses.