Development of a rutting index parameter based on the stress sweep rutting test and permanent deformation shift model

ABSTRACT

The use of index parameters to evaluate the performance of asphalt mixtures has become an important process for making informed pavement material decisions. These index parameters are indicators of asphalt mixture performance and thus are widely used in the asphalt paving industry. This paper presents a new rutting index parameter to assess the rutting resistance of asphalt mixtures using the stress sweep rutting test and the permanent deformation shift model. The proposed parameter, referred to as the Rutting Strain Index (RSI), is novel in that it integrates material testing and structural simulations. To develop the RSI index parameter, more than 70 mixtures from different geographical locations that exhibit a wide variety of performance were evaluated. The results show that the RSI is able to capture the effects of mix design factors, such as RAP content, binder content, and volumetric properties. Furthermore, a set of RSI threshold values are proposed for different allowable traffic levels in terms of rutting. The RSI can be employed by agencies as a tool for performance engineered mix design and quality assurance purposes whereby agencies will be able to accept or reject a mixture based on RSI thresholds.

KEYWORDS:

• Asphalt mixture
• rutting
• index parameter
• stress sweep rutting (SSR) test
• shift model
• rutting strain index (RSI)

Acknowledgment

The authors would like to acknowledge the financial support from the Federal Highway Administration under the DTFH61-13-C-00025 and DTFH61-14-D-00008 Projects.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was supported by Federal Highway Administration: [Grant Number DTFH61-13-C-00025,DTFH61-14-D-00008].