EVALUATING THE STABILITY OF ASPHALTIC CONCRETE ROAD SURFACES UNDER TEMPERATURE VARIATIONS USING MARSHALL TESTING

Abstract

Asphalt binder is a thermoplastic material that exhibits elastic, solid-like behaviour at low service temperatures or under rapid loading rates. Conversely, at high temperatures or under slow loading rates, the asphalt binder transitions to a viscous, liquid-like state. This dual behaviour underscores the importance of evaluating the mechanical properties of asphalt concrete at expected service temperatures to mitigate stress cracking and fatigue at lower temperatures and plastic deformation (rutting) at higher temperatures.

In this study, Marshall tests were utilized effectively to analyze the impact of temperature on the mechanical properties of asphalt mixtures. Limestone aggregate, sourced from the Mahroga Crusher, served as the primary material. Seventy-two Marshall samples were prepared using mixtures optimized for bitumen content, as determined by the Marshall test. These mixtures incorporated 60/70 penetration-grade asphalt cement imported from Italy. Stability test results revealed an increase in stability values at temperatures below 60°C (specifically at 50°C and 55°C), while stability values decreased at higher temperatures (such as 65°C and 70°C).