Development and Evaluation of a Simplified Superpave IDT Testing System for Implementation in Mix Design and Control

Asphalt mixtures designed using modern conventional methods, whether Marshall or Superpave methodologies, fail to address the cracking performance of these mixtures. Research previously conducted at the University of Florida for the Florida Department of Transportation has identified key mixture parameters that control cracking performance. These parameters can be obtained from a series of relatively simple tests performed using the Superpave indirect tension tests (IDT). Traditionally, this equipment is large, heavy, requires fixed utilities, and specialized training. A Simple IDT testing platform has been developed that removes these restrictions. This platform is small, and portable, incorporating all of the most important performance features of the heavier fixed systems. Evaluation of the Simple IDT was conducted, at three different testing temperatures, using a laboratory prepared mixture. The results show equivalent comparison of the key mixture parameters versus two different fixed IDT systems, one at UF and the other at the FDOT State Materials Office. Additionally, software has been developed to aid the operator in performing the tests on the Simple IDT, thereby reducing the need for specialized training. Work continues refining a sensor system to measure the on-specimen deformations, which would eliminate the need to glue targets or gage points on the specimen faces, reducing this additional specimen preparation.