Cold In-Place Recycling as a Sustainable Pavement Practice

Abstract

Pavement rehabilitation and reconstruction methods with CIR (cold in-place recycling) are alternatives that can effectively reduce the high stresses and waste produced by conventional pavement strategies. An attempt was made to predict the performance, particularly low-temperature cracking resistance characteristics of CIR mixtures. These were prepared with the mix design procedure developed at the URI (University of Rhode Island) for the FHW A (Federal Highway Administration) to reduce wide variations in the application ofCIR mixtures production. This standard was applied to RAP (reclaimed asphalt pavement) to produce CIR mixtures with CSS-lh asphalt emulsion as the additive. By adjusting the number of gyrations of the SGC (Superpave gyratory compactor) for compaction, the field density of 130 pcf was represented accurately. To secure a base line, HMA (hot mix asphalt) samples were produced according to the Superpave volumetric mix design procedure. The specimens were tested using the IDT (indirect tensile) tester according to the procedure of AASHTO T 322 procedure at temperatures of -20, -10 and 0 °C ( -4, 14, and 32 Gp, respectively). The obtained results for the creep compliance and tensile strength were used as input data for the MEPDG (mechanistic empirical pavement design gnide ). 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. Thus, it appears that CIR is a sustainable rehabilitation technique which is also suitable for colder climates, and it is reconunended to conduct further investigation ofload-related distresses such as rotting and fatigue cracking.