Field Evaluation of Recycled Pavement Materials at MnROAD

• Published in: Paving Materials and Pavement Analysis pp. 264 - 269
• Main Authors: Patton, Robert, Clyne, Timothy R, Wen, Haifang, Edil, Tuncer, Martono, Wilfung
• Format: Book Chapter
• Language: English
• Published: American Society of Civil Engineers (ASCE) 2010
• Subjects: Asphalt & Bituminous Materials; Civil Engineering & Construction Materials; Pavements; Recycling
• ISBN: 9780784411049; 0784411042
• DOI: 10.1061/41104(377)32

In-place recycling of asphalt pavement is an inexpensive and sustainable pavement rehabilitation method. Existing Hot Mix Asphalt (HMA) layer is pulverized and blended with some of or the entire base course to form a broadly graded material referred to as recycled pavement material (RPM). RPM can be compacted as the new base course and overlaid by a new layer of HMA. Additives may be added to improve the properties of RPM base course, such as cement or fly ash. In this study, three flexible pavement sections with different base materials were constructed at MnROAD test facility to evaluate the RPM with and without fly ash additive and to compare them with conventional crushed aggregate base course, Minnesota Department of Transportation Class 6 aggregates. The fly ash used was a high carbon and high calcium content off-specification self-cementitious fly ash. Various field tests were conducted, using dynamic cone penetrometer, lightweight deflectometer, soil stiffness gauge, and falling weight deflectometer. The backcalculated modulus of base materials from these field tests were compared with each other and with the resilient modulus from laboratory tests. It was found that there are significant differences in the moduli from different test methods. It is believed that this is due to the stress and strain dependence of these materials. However, in any case, the fly ash stabilized RPM has higher modulus than RPM, followed by Class 6.