Fatigue behavior study of a dense graded HMA using the four point bending beam test aided by an in-situ instrumentation at BR-116/RS, Brazil

Abstract

Fatigue is characterized by structural deterioration of a material when subjected to a state of repeated stress-strain cycles, thus resulting in cracking of the pavement and eventual failure after a sufficient number of cycles. The laboratory test commonly employed in Brazil to analyze the fatigue life is the indirect tensile test (IDT) under controlled stress. An alternative test method is the four-point bending beam test (4PBBT), which leads the material to a more realistic stress-state. This work examined the fatigue behavior of an asphalt mixture with polymer-modified binder (PG76-11) using both IDT and 4PBBT. A road segment at BR-116/RS was instrumented to monitor mechanic responses in the asphalt layer allowing the evaluation of the material under real traffic, and through real-time monitoring, enabling a better understanding of the distress levels in the structure. The results also demonstrate a closer relation between the 4PBB tests with in-service pavement fatigue development.

Keywords

• IDT fatigue test
• Four point bending test
• Pavement instrumentation
• Fatigue performance.