Reliability comparison of two-point and four-point bending tests for coarse aggregate mixtures

Petr Veselý, Ondřej Dašek

Last modified: 2024-04-10

Abstract


This paper investigates the reliability and comparative performance of two European standardized methods for assessing the stiffness and fatigue characteristics of asphalt mixtures with coarse aggregates up to 32 mm in grain size. European standards currently prescribe many various approaches to testing fatigue properties of asphalt mixtures, mainly two distinct methodologies: the two point bending test and the four point bending test. Despite the availability of both methods, certain laboratories predominantly prefer the two point bending test.
The study focuses on a comprehensive set of tests conducted on asphalt mixtures containing coarse aggregates with a maximum grain size of 32 mm, applying both the two point and four point bending tests. The primary objective is to assess the reliability of these methods, particularly in the context of larger aggregate sizes. A crucial consideration arises from the fact that the two point bending test uses smaller specimens, potentially leading to an increased likelihood of test specimen failure in coarse aggregate asphalt mixtures.
The experimental approach involves subjecting asphalt specimens to fatigue loading using both testing methods, systematically analysing the resulting data, and comparing the stiffness and fatigue performance outcomes. The findings contribute valuable insights into the appropriateness and reliability of the chosen testing methodologies, aiding practitioners and researchers in making informed decisions regarding the selection of fatigue testing protocols for asphalt mixtures with coarse aggregates.

Keywords


Coarse asphalt mixture; two-point bending test; four-point bending test; fatigue; stiffness