The Influence of Curing Methods on Marshall Stability and Flow

Abstract

The Marshall Mix design is one of the most widely used methods for designing and evaluating hot asphalt mixes globally, and the main Marshall Test focuses are stability and flow. Two standard curing methods are normally followed to elevate the temperature of testing samples; these involve immersing the samples in 60°C water or placing the samples in an oven at 60°C. These standard curing methods may not simulate the actual state of heating of asphalt pavement in the field, however. In this research, a new curing method that includes insulating the samples before immersion in hot water is thus introduced and compared with the two standard curing methods. During immersion, the water temperature is increased to 60°C and the core temperature of the insulated samples determined. Three sets of Marshall Samples were prepared and cured using the outlined methods; each set consisted of 18 specimens of 101 mm diameter and 63.5 mm height. All specimens were tested using the Marshall Test for stability, flow, and Marshall Stiffness. The set mean results showed that the oven cured samples demonstrated the highest stability values, followed by the standard water cured samples, while the insulated samples exhibited the lowest stability values. The oven cured samples also exhibited higher Marshall Stiffness Index (MSI) values than the other curing methods. However, one-way ANOVA (single factor) testing demonstrated that these differences were not statistically significant.