New and Simpler Cracking Test Method for Asphalt Mix Designs

Because of environmental conservation and sustainability concerns, reclaimed asphalt pavements and recycled asphalt shingles are increasingly used in the asphalt paving industry to replace virgin asphalt and aggregate materials. However, these recycled materials are often highly aged and can cause cracking issues for asphalt pavements. Additionally, other factors such as binder additives, modifiers, and multiple warm-mix asphalt technologies can alter the performance of the mixtures both positively and negatively. The volumetric mix design alone is not sufficient for evaluating the potential cracking behavior of asphalt mixes. Although many cracking test methods are available, there is no widely accepted performance-related cracking test method that is practical enough for routine use in asphalt mix designs. This paper presents a newly developed, simple, and practical cracking test method for asphalt mix designs. The new cracking test method is repeatable, time- and cost-effective, easily implemented, sensitive to mix compositions, and well correlated to field performance. The new cracking test is performed at an intermediate temperature of 25°C and a loading rate of 50 mm/min. Furthermore, a unitless index is proposed as the cracking resistance indicator for evaluation of the cracking resistance of asphalt mixes. Additionally, the effectiveness of the new cracking test was validated with the test results from FHWA’s accelerated loading facility.