Material Testing Apparatus and Procedures for Evaluating Freeze-Thaw Resistance of Asphalt Concrete Mixtures

Abstract

This paper presents material testing procedures using an ASTM C666 (Standard Test Method for Resistance of Concrete to Rapid Freezing and Thawing) apparatus to evaluate resistance of asphalt concrete (AC) mixtures with respect to freeze-thaw (F-T) cycles. The ASTM C666 apparatus is mostly used for testing F-T resistance of pervious concrete, but it can be an ideal device to replace the currently used AASHTO T283, Standard Method of Test for Resistance of Compacted Asphalt Mixtures to Moisture-Induced Damage, as it was never intended to simulate F-T resistance for asphalt mixtures. To evaluate the effectiveness of the ASTM C666 apparatus in determination of F-T resistance of asphalt mixtures, two types of AC materials were sampled from an asphalt paving project: rubberized modified asphalt (RMA) and fiber reinforced asphalt (FRA). All specimens were prepared in the Materials Laboratory of Northern Arizona University, and their F-T resistance was tested using an ASTM C666 apparatus at six designed cycles: 0, 100, 150, 200, 250, and 300 cycles. After each desired cycle is complete, specimens were removed from the ASTM C666 apparatus and then tested for their stiffness using a bending beam rheometer (BBR). The viscoelastic reposes of asphalt mixtures tended to be less significant after 150 F-T cycles. The field evaluation of local asphalt paving associated with climatic F-T cycle data and F-T test results indicate that surface conditions and cracking progress of the asphalt pavements do have closer agreement with the increase of F-T cycles. The ASTM C666 apparatus is capable of providing F-T conditioning of the specimens. In combination of the BBR device and the corresponding procedure, the thermal properties of the mix (e.g., stiffness at 60 s or relaxation modulus function) can be measured and determined. The testing procedures and results are promising and prone to the purposes of F-T resistant simulation. The findings presented in this paper provide a positive trend for future research focusing on the evaluation of long-term F-T durability of asphalt mixtures.