PERFORMANCE PREDICTION OF PAVEMENTS WITH COLD IN-PLACE RECYCLING ASPHALT MIXTURES

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The pavement rehabilitation and reconstruction method with Cold In-Place Recycling (CIR) is an alternative that can effectively conserve materials and energy, preserve the environment and reduce the cost. An attempt was made to predict the performance, particularly low-temperature cracking resistance characteristics of CIR mixtures prepared with the mix design procedure developed at the University of Rhode Island (URI) for the Federal Highway Administration (FHWA). The mix design procedure was developed to reduce wide variations in CIR mixture production and to develop a nation-wide standard. This standard was applied to a Rhode Island (RI) reclaimed asphalt pavement (RAP) to produce CIR mixtures with CSS-1h asphalt emulsion as the additive. By adjusting the number of gyrations of the Superpave Gyratory Compactor (SGC) for compaction, the field density of 130 pcf was achieved in the laboratory. To secure a base line, hot mix asphalt (HMA) samples were produced first according to the Superpave volumetric mix design procedure with an air void content of 4.0%. These were tested and analyzed parallel to the CIR specimens to compare the performances. The specimens were tested using the Indirect Tensile (IDT) tester at temperatures of -20, -10 and 0°C (-4, 14, and 32°F, respectively) in accordance with the AASHTO T 322 procedure. The creep compliance and tensile strength values were used as input data for the Mechanistic Empirical Pavement Design Guide (MEPDG) analysis. This software predicts the performance of roadways with different pavement structures, traffic, environmental conditions, and material properties using several mathematical models for different types of distresses. The analysis results indicated that no thermal or low-temperature cracking is expected over the entire analysis period of 20 years for both HMA and CIR mixtures. It confirms with the field performance in Arizona. Thus, it appears that CIR is a sustainable rehabilitation technique, and it justifies further research on and investigation of load-related distresses such as rutting and fatigue cracking.