SYMPOSIA PAPER Published: 01 January 1985

The Use of a Gyratory Testing Machine in the Evaluation of Cold-Recycled Asphalt Paving Mixtures


This study evaluated the feasibility of using the gyratory testing machine in the fixed roller mode for evaluating the long-term behavior of cold-recycled asphalt mixtures. Cold recycled asphalt mixtures were compacted with the gyratory machine, and gyratory strain indices were obtained from the gyrograph recorded during the compaction process. The resilient modulus, Hveem stabilometer R value, and Marshall stability were obtained on the compacted recycled mixes at various curing times and were correlated to the gyratory strain indices. The scope of study presented in this paper covered two types of pavement material and five types of added softening agents, which included a high-float asphalt emulsion AE-150, a foamed asphalt and the rejuvenating agents, Reclamite®, Mobilsol®, and Dutrex 739®.

The results of the study indicated that the gyratory stability index (GSI) and the gyratory elasto-plastic index (GEPI) could be used to detect unstable mixtures when the binder content was too high. The GSI and GEPI correlated fairly well with the Hveem stabilometer R value of the recycled mix. However, they correlated poorly with the resilient modulus and Marshall stability of the recycled mix. Similar to the R-value test, the gyratory testing machine can be used to determine the optimum binder content of a cold-recycled mix.

The scope of this study was limited to the use of the gyratory testing machine in the fixed roller mode. Tests using the oil filled roller mode had not been conducted in this investigation.

Author Information

Tia, M
Weil Hall, University of Florida, Gainesville, FL
Wood, LE
School of Civil Engineering, Civil Engineering Building, Purdue University, West Lafayette, IN
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Developed by Committee: D04
Pages: 74–94
DOI: 10.1520/STP32921S
ISBN-EB: 978-0-8031-4945-8
ISBN-13: 978-0-8031-0424-2